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Quaestiones

Entomologicae

VOLUME 16

1980

CONTENTS

Perkins - Aquatic beetles of the family Hydraenidae in the Western Hemisphere: classification,

biogeography and inferred phylogeny (Insecta:Coleoptera) 5

Pike - Origin of tundra butterflies in Alberta 555

Halffter, Halffter and Huerta - Mating and nesting behavior of Eurysternus (Coleoptera:

Scarabaeinae) 597

Smith and Lehmkuhl - The larvae of four Hydropsyche species with the checkerboard head

pattern (Trichoptera: Hydropsychidae) .621

Smith and Lehmkuhl - Analysis of*two problematic North American caddisfly species: Oecetis

avara (Banks) and Oecetis disjuncta (Banks) ( Trichoptera : Leptoceridae) . 635

Donald and Mutch - The effect of Hydroelectric dams and sewage on the distribution of

stoneflies (Plecoptera) along the Bow River 657

Smith - Sawflies (Hymenoptera: symphyta) from George Lake, Alberta 671

Book Review-Griffiths, G.C.D. 1980. Flies of the Nearctic Region. 676

Book Review-Howden, H.F. and O.P. Young. 1981. Panamanian Scarabaeinae:Taxonomy,

distribution and habits (Coleoptera, Scarabaeidae). 678

Book Review-Reigert, P.W. 1980. From arsenic to DDT: A history of entomology in western

Canada . 679

Book Review-Matthews, E.G. 1980. A guide to the genera of beetles of South Australia. Part

1. 681

Editor’s acknowldgements 683

Index 685

6 13

Ent

y Quaestiones"

Entomologicae

A periodical record of entomological investigations,
published at the Department of Entomology,
University of Alberta, Edmonton, Canada.

VOLUME 16

NUMBERS 1, 2

JANUARY-APRIL 1980

/

QUAESTIONES ENTOMOLOGICAE

ISSN 0033-5037

A periodical record of entomological investigation published at the Department of
Entomology, University of Alberta, Edmonton, Alberta.

Volume 16

Number 1,2

January 1980

CONTENTS

Perkins - Aquatic beetles of the Family Hydraenidae in the Western Hemisphere:

Classification, Biogeography and Inferred Phylogeny (Insecta:Coleoptera) . . 5

Fig. 1. Dorsal habitus of (clockwise from top left) Hydraena marginieollis , Hydraena cuspidicollis, Spanglerina brevis
and Limnebius alutaceus (not to same scale).

AQUATIC BEETLES OF THE FAMILY HYDRAENIDAE IN THE WESTERN
HEMISPHERE: CLASSIFICATION, BIOGEOGRAPHY AND INFERRED PHYLOGENY

(INSECTA: COLEOPTERA)

PHILIP DON PERKINS

c/o Department of Entomology

National Museum of Natural History

Smithsonian Institution Quaestiones Entomologicae

Washington, D.C. 20560 16:3-554 1980

The aquatic beetle family Hydraenidae in the Western Hemisphere includes nine genera
and 206 species. One genus, Spanglerina (type species S. ingens new species ), is described as
new; two genera, Gymnochthebius and Neochthebius, are elevated from subgeneric rank. New
species (142) are described in the following genera: Hydraenida (1), Parhydraenida (5),
Hydraena (77), Spanglerina (3), Limnebius (11), Gymnochthebius (14), Ochthebius (30) and
Meropathus (1). New synonomies are proposed in Hydraena (1), Limnebius (3),
Gymnochthebius (2) and Ochthebius (7).

Taxonomically and phylogenetically significant structures are illustrated with line
drawings or scanning electron micrographs, and geographical distributions are mapped.
Natural history data are noted for genera and, when available, species. Keys to genera, species
groups, and species are given.

Morphological features unique to the family, including abdominal and aedeagal structure,
are discussed with respect to homologies, and illustrated. Internal reproductive systems of
representative species are illustrated and discussed.

Phylogenetic relationships of the genera are proposed using inferred synapotypic character
states of larvae (external) and adults (external and internal). As a result, a new subfamily,
Ochthebiinae, is proposed, the Hydraeninae is redefined and the Limnebiinae is reduced to
subtribal rank. Geographical distributions of genera and species groups are briefly discussed
with respect to continental drift, global distribution and available fossil data.

Phylogenetic relationships of all species and species groups are presented in phylograms,
together with generalized distribution maps to illustrate repetitive vicariance patterns and
serve as a data base for further studies of historical biogeography. Vicariance zones are
proposed based upon coincident sister-group patterns. North American and some Middle
American vicariance zones are discussed relative to paleogeological events. Based upon
coincidence of vicariance zones and paleogeological events, dichotomies are placed in
mid-Cretaceous, Miocene, Pliocene, and Pleistocene times. Endemism is discussed relative to
vicariance zones.

The following new species are described (type localities parenthetic): Hydraenida robusta
(Maule, Chile); Parhydraenida bubrunipes (Nova Teutonia, Santa Catarina, Brazil),
Parhydraenida hygropetrica (Santa Teresa, Espirito Santo, Brazil), Parhydraenida lambda
(Jaguariaiva, Parana, Brazil), Parhydraenida paralonga (Campos do Jordao, Sao Paulo,
Brazil), Parhydraenida pentatenkta (Portoviejo, Manabi, Ecuador); Spanglerina fluvicola
(Oaxaca, Mexico), Spanglerina frondsicola (Nayarit, Mexico), Spanglerina ingens (Mexico,
Mexico); Limnebius arenicolus (Los Angeles Co., California),

6

Perkins

Limnebius aridus ( Hidalgo Co., New Mexico), Limnebius borealis ( British Columbia,
Canada ), Limnebius leechi ( Mendocino Co., California), Limnebius mexicanus ( Oaxaca ,
Mexico), Limnebius mitus ( Zacatecas , Mexico), Limnebius octolaevis (Totonicapan,
Guatemala), Limnebius ozapalachicus ( Bath Co., Virginia), Limnebius richmondi (Lewis Co.,
New York), Limnebius texanus (Culberson Co., Texas), Limnebius utahensis (Wasatch Mts.,
Utah); Gymnochthebius bartyrae (Lima, Peru), Gymnochthebius bisagittatus (Cundinamarca,
Colombia), Gymnochthebius clandestinus (Maule, Chile), Gymnochthebius compactus
(Parana, Brazil), Gymnochthebius curvus (Valdivia, Chile), Gymnochthebius falli (Logan Co.,
Kansas), Gymnochthebius maureenae (George Co., Mississippi), Gymnochthebius octonarius
(Tucuman, Argentina), Gymnochthebius oppositus (Baja California, Mexico),
Gymnochthebius perlabidus (Limon, Costa Rica), Gymnochthebius plesiotypus (Concepcion
region, Chile), Gymnochthebius reticulatissimus (Tucuman, Argentina), Gymnochthebius
seminole (Monroe Co., Florida), Gymnochthebius tectus (Maule, Chile); Meropathus vectis
(Isla de los Estados, Argentina).

New species of Ochthebius are: Ochthebius alpinopetrus (Natrona Co., Wyoming),
Ochthebius angularidus (Coahuila, Mexico), Ochthebius apache (Cochise Co, Arizona),
Ochthebius arenicolus (Colusa Co., California), Ochthebius arizonicus (Gila Co., Arizona),
Ochthebius biincisus (Monterey Co., California), Ochthebius bisinuatus (Trinity Co.,
California), Ochthebius borealis (Glenn Co., California ), Ochthebius brevipennis (Tillamook
Co., Oregon), Ochthebius browni (Mexico, Mexico), Ochthebius californicus (Tulare Co.,
California), Ochthebius crassalus (Ventura Co., California), Ochthebius gruwelli (Baja
California, Mexico), Ochthebius hibernus (Oregon), Ochthebius lecontei (British Columbia,
Canada), Ochthebius madrensis (Cochise Co., Arizona), Ochthebius mesoamericanus (Jalapa,
Guatemala), Ochthebius mexicanus (Mexico, Mexico), Ochthebius mexcavatus (Durango,
Mexico), Ochthebius orbus (Marin Co., California), Ochthebius pacificus (Sonoma Co.,
California), Ochthebius pauli (Oaxaca, Mexico), Ochthebius recticulus (Colusa Co.,
California), Ochthebius rectusalsus (Contra Costa Co., California), Ochthebius reticulocostus
(Mexico, Mexico), Ochthebius richmondi (Humboldt Co., California), Ochthebius sculptoides
(Ventura Co., California), Ochthebius sierrensis (Fresno Co., California), Ochthebius tubus
(Baja California, Mexico), Ochthebius uniformis (San Francisco Co., California).

New species of Hydraena are: Hydraena alternata (Durango, Mexico), Hydraena alterra
(Minas Gerais, Brazil), Hydraena anaphora (Matto Grosso, Brazil), Hydraena ancylis (York
Co., Pennsylvania), Hydraena anisonycha (Cundinamarca, Colombia), Hydraena
appalachicola (Bath Co., Virginia), Hydraena arenicola (Lake Co., California), Hydraena
arizonica (Santa Cruz Co., Arizona), Hydraena argutipes (Durango, Mexico), Hydraena
atlantica (Montgomery Co., Maryland), Hydraena barricula (Chiapas, Mexico), Hydraena
bituberculata (Cochise Co., Arizona), Hydraena bractea (Durango, Mexico), Hydraena
bractoides (Durango, Mexico), Hydraena breedlovei (Durango, Mexico), Hydraena browni
(Guarico, Venezuela), Hydraena californica (Marin Co., California), Hydraena campbelli
(Chiapas, Mexico ), Hydraena canticacollis (Zacatecas, Mexico), Hydraena chiapa (Chiapas,
Mexico), Hydraena circulata (Butte Co., California ), Hydraena colombiana (Cundinamarca,
Colombia), Hydraena colymba (Jalapa, Guatemala), Hydraena costiniceps (Salta, Argentina),
Hydraena crystallina (Jalisco, Mexico), Hydraena cuspidicollis (Oaxaca, Mexico), Hydraena
d-destina (Chiapas, Mexico), Hydraena exilipes (Tamaulipas, Mexico), Hydraena geminya
(Oaxaca, Mexico), Hydraena guatemala (Escuintla, Guatemala), Hydraena haitensis (Etang
Lachaux, Haiti), Hydraena hyalina (Guarico, Venezuela ), Hydraena jivaro (Napo, Ecuador ),

Western Hemisphere Hydraenidae

7

Hydraena leechi ( Coconino Co., Arizona), Hydraena limpidicollis ( Canal Zone, Panama),
Hydraena malkini (Tres Rios, Costa Rica), Hydraena maureenae (Bath Co., Virginia),
Hydraena mazamitla ( Jalisco , Mexico), Hydraena mexicana (Chiapas, Mexico), Hydraena
mignymixys (Lake Co., California), Hydraena nevermanni (Reventazon, Costa Rica),
Hydraena newtoni (Canal Zone, Panama), Hydraena oaxaca (Oaxaca, Mexico), Hydraena
oblio (Baja Verapaz, Guatemala), Hydraena occidentalis (Mendocino Co., California),
Hydraena orcula (Goias, Brazil), Hydraena ozarkensis (McDonald Co., Missouri), Hydraena
pacifica (British Columbia, Canada), Hydraena paeminosa (Zanderij, Surinam ), Hydraena
particeps (Guarico, Venezuela), Hydraena pavicula (Lima, Peru), Hydraena peru (Huanuco,
Peru), Hydraena petila (Tehama Co., California), Hydraena pontequula (Canal Zone,
Panama), Hydraena premordica (Mayaro, Trinidad), Hydraena prieto (Durango, Mexico),
Hydraena pulsatrix (Tamaulipas, Mexico ), Hydraena quadricurvipes (Chattooga Co.,
Georgia), Hydraena quechua (Los Rios, Ecuador), Hydraena sabella (Chiapas, Mexico),
Hydraena scintilla (Oaxaca, Mexico), Hydraena scintillabella (Cundinamarca, Colombia),
Hydraena scintillutea (Minas Gerais, Brazil), Hydraena scolops (Mexico, Mexico), Hydraena
scopula (Jalisco, Mexico), Hydraena sierra (Madera Co., California), Hydraena spangleri
(Montgomery Co., Maryland), Hydraena splecoma (Chiapas, Mexico), Hydraena terralta
(Minas Gerais, Brazil ), Hydraena trinidensis (St. Augustine, Trinidad), Hydraena tucumanica
(Tucuman, Argentina), Hydraena tuolumne (Tuolumne Co., California), Hydraena turrialba
(Turrialba, Costa Rica), Hydraena vela (Nayarit, Mexico), Hydraena yosemitensis (Mariposa
Co., California), Hydraena youngi (Alachua Co., Florida), Hydraena zapatina (Jalisco,
Mexico).

The following new synonymies are proposed (junior names parenthetic): Limnebius
alutaceus (Casey) (L. columbianus Brown, L. congener Casey), L. angustulus (Casey) (L.
coniciventris (Casey)); Gymnochthebius fossatus (LeConte) (G. nitiduloides (d’Orchymont), G.
parvulus (Sharp)); Ochthebius interruptus LeConte (O. aberti Hatch), O. aztecus Sharp (O.
bruesi Darlington), O. marinus (Paykull) (O. holmbergi Maklin), O. discretus LeConte (O.
insulanus Brown), O. lineatus LeConte (O. milleri Hatch), Ochthebius attritus LeConte (O.
schubarti d’Orchymont), Ochthebius similis Sharp (O. wickhami Fall); Hydraena punctata
LeConte (H. needhami d’Orchymont ).

La famille de coleopteres aquatiques des Hydraenidae compte, dans I’hemisph'ere ouest, neuf genres et 206 especes.
Un genre nouveau. Spanglerina (espece type, S. ingens, especes nouveau ). est decrit; les sous-genres Gymnochthebius et
Neochthebius sont eleves au rang de genre. Un total de 142 especes nouvelles sont decrites dans les genres suivants:
Hydraenida (I), Parhydraenida (5), Hydraena (77). Spanglerina (3), Limnebius (II), Gymnochthebius (14), Ochthebius
(30) et Meropathus ( I ). De nouveaux synonymes sont proposes dans les genres Hydraena (1), Limnebius (3),
Gymnochthebius (2) et Ochthebius (7).

Les structures d’une importance taxonomique et phylogenetique particuliere sont illustrees par des dessins ou des
photos prises au microscope a balayage electronique; la repartition geographique des taxons est presentee sur des cartes.
Les donnees d'histoire naturelle sont presentees pour chaque genre et, lorsque disponibles, pour les especes. Des cles
d’ identification sont fournies pour les genres, les groupes d’especes et les especes.

Les caracteres morphologiques uniques a la famille sont illustres et discutes en relation avec leurs homologues, et
incluent des structures de V abdomen et de I’edeage. Les parties internes du systeme reproducteur d’especes
representatives sont illustrees et discutees.

Les relations phylogenetiques des genres sont etablies a partir de synapotypies des larves (caracteres externes
seulement) et des adultes (caracteres externes et internes). En consequence, une nouvelle sous-famille, celle des

Quaest. Ent., 1980, 16 (1,2)

8

Perkins

Ochthebiinae, est proposee, les Hydraeninae sont redefinis et les Limnebiinae sont abaisses an rang de sous-tribu. La
repartition geographique des genres et des groupes d'especes est brievement discutee en relation avec la derive des
continents, la distribution globale de la famille et les fossiles disponibles.

Les relations phylogenetiques de toutes les especes et de tous les groupes d’especes sont illustrees par des
phylogrammes; a celles-ci sont adjointes des cartes illustrant les distributions generalises, qui montrent les patrons
repetitifs de vicariance et qui pourront servir de donnees de base pour des etudes eventuelles sur la biogeographie
historique. Les zones de vicariance sont determinees a partir des distributions co'incidentes de groupes apparentes. Les
zones de vicariance de I’Amerique du Nord et de I’Amerique Centrale sont discutees en rapport avec des evenements
paleontologiques. Suivant la coincidence des zones de vicariance et les evenements paleontologiques qui leur sont
associes, les dichotomies devraient dater du Cretace Moyen, du Miocene, du Pliocene et du Pleistocene. Les cas
d’endemisme sont interprets en rapport avec les zones de vicariance.

Les noms des especes nouvelles (ainsi que les localites types) sont enumer&s dans le resume anglais.

TABLE OF CONTENTS

Introduction 8

Natural History 11

Criteria for Species Level Taxa 13

Methods and Materials . . 14

Morphological Analysis 15

Key to Genera of Western Hemisphere Hydraenidae 34

Checklist of Western Hemisphere Hydraenidae 36

Genus Hydraenida Germain 40

Genus Parhydraenida J. Balfour-Browne 45

Genus Hydraena Kugelann 60

Genus Spanglerina, new genus 212

Genus Limnebius Leach 222

Genus Gymnochthebius d’Orchymont 244

Genus Ochthebius Leach 292

Genus Meropathus Enderlein 406

Genus Neochthebius d’Orchymont 408

Phylogenetic Relationships and Zoogeography 410

Epilogue 481

Appendix A: Paratypes and Material Examined 482

Appendix B: Tabulary Summary 525

Acknowledgements 536

References 537

Index 544

INTRODUCTION

Adults of Hydraenidae are minute aquatic beetles, most of which are slightly less than
2.00 mm long and found at the margins of aquatic habitats, especially streams. They have been

Western Hemisphere Hydraenidae

9

termed “minute moss beetles” by some, but in actuality a very small percentage of species are
associated with moss. Most species live in sandy or gravelly aquatic situations, therefore, a
more appropriate common name for the family might be “micropsammophilous aquatic
beetles”.

Generalities regarding the habits of the family are difficult to make since, as in any
consideration of a rather large evolutionary unit, exceptions abound. Hence, various kinds of
hydraenid beetles live in such diverse aquatic habitats as hot springs, cold mountain streams,
rapid tropical cascades, saline beach pools, cracks in rocks covered at high tide, and vertical
rock faces in hygropetric habitats.

Although the family is relatively small in most respects, including size of individuals,
number of species and generic diversity, from an evolutionary and biogeographic viewpoint it is
one of the most interesting members of the series Staphyliniformia. Hydraenids have a curious
combination of characters and habits which have resulted in their placement with the primitive
Staphylinoidea by some authors, and with the Hydrophiloidea by others.

The family has not been studied in a collective, monographic manner, and none of the
Western Hemisphere genera have been treated in a modern, revisionary context. Most
descriptions of Western Hemisphere species are scattered throughout the literature, and
illustrations of taxonomically important structures are the exception.

This study stems from an earlier investigation in which I attempted to elucidate taxonomic
characters to differentiate larvae of a few species of hydraenids in southern California.
Although I was able to rear larvae and therefore definitely associate the adult and larval forms
of a species, it soon became apparent that taxonomic literature on the adults was quite
inadequate. Consequently, although differentiating characters were found for the larvae, the
taxa they represented remained problematic. This work will correct that situation, and,
hopefully, provide a stimulus and stable basis for future studies on the immature stages.

The family Hydraenidae was first proposed by d’Orchymont (1919) based upon criteria he
had presented previously (1916). These criteria included some considerations of both larval and
adult structures, and resulted in the organization of the included taxa in three subfamilies:
Hydraeninae, Limnebiinae, and Spercheinae. These three groups had originally been placed in
the Hydrophilidae.

Twelve years later, Boving and Craighead (1931) published their extensive work on the
larvae of Coleoptera, in which they concluded that the genera Limnebius , Hydraena and
Ochthebius constituted a family in the “leptinid association” of the Staphylinoidea, and
proposed the name Limnebiidae, whereas Spercheus was afforded familial rank within the
Hydrophiloidea. Apparently Boving and Craighead were unaware of d’Orchymont’s previous
work.

Leech (1948) was the first American entomologist to point out that d’Orchymont’s name
Hydraenidae was published prior to Boving and Craighead’s Limnebiidae; he also indicated
that the name may be credited to Mulsant (1844). Leech (1948) states, “Judging from the
recent work of students in other orders of insects, and their interpretation of the International
Rules and of Opinion 133, the name Limnebiidae should be credited not to Boving but to
Mulsant who proposed it as ’Limnebiaires’ (1844: 88). On the other hand, the name
Hydraenidae has been in use for many years by d’Orchymont, and perhaps should take
precedence. It too may be credited to Mulsant (1844: 27), based on his ‘Hydraenaires’.”

Later, Leech (in Leech and Chandler, 1956) used the name Hydraenidae in his review of
the United States genera and California species. Nevertheless, during the 1960’s the incorrect

Quaest. Ent., 1980, 16 (1,2)

10

Perkins

name Limnebiidae continued to appear in general works by American authors (e.g., Borror and
DeLong, 1964; Arnett, 1968). More recent works by American authors (e.g., Doyen and
Ulrich, 1978) use the name Hydraenidae, and the name has been in use by European authors
since it was proposed by d’Orchymont (1919).

LIST OF ABBREVIATIONS

The following abbreviations in the text indicate collections from which material was
borrowed and the repository of specimens.

AFN

AG

AMNH

ASP

BMNH

CAS

CCW

CFMNH

CMP

CNC

CSQ

CU

DCM

DPW

EJK

FNY

GWF

HM

HNHM

HPB

INHS

IOJ

ISNB

ISU

JEC

JFB

JLC

JLH

JS

KS

LACM

LSU

MCZ

MHNC

MSP

MU

NDSU

NMD

NYSS

ODA

ORSU

OSU

PBPI

PDP

PM

PMNH

PU

A.F. Newton, Jr., Museum of Comparative Zoology, Flarvard University, Cambridge, Massachusetts
A. Gillogly, Fort Baker, California

L.H. Herman, American Museum of Natural History, New York
Academy of Natural Sciences, Philadelphia

P. Hammond, M.E. Bacchus, British Museum (Natural History), London

H.B. Leech, D.H. Kavanaugh, California Academy of Sciences, San Francisco

W.R. Suter, Carthage College, Wisconsin

H. Dybas, Field Museum of Natural History, Chicago

G. Wallace, Carnegie Museum, Pittsburgh

A. Smetana, Canadian National Collection, Ottawa

R. Beique, Complexe scientifique du Quebec

L. L. Pechuman, Cornell University, New York

D. C. Miller, City College of New York

C.P. Wooldridge, Pennsylvania State University, University Park, Pennsylvania

E. J. Kiteley, Quebec

F. N. Young, Univeristy of Indiana, Bloomington, Indiana

G. W. Folkerts, Auburn University, Auburn, Alabama

H. Silfverberg, Helsinki Museum

Z. Kaszab, Hungarian Natural History Museum, Budapest
Harley f\ Brown, University of Oklahoma, Norman, Oklahoma

M. W. Sanderson, Illinois Natural History Survey

T.H. Farr, Science Museum, Institute of Jamaica, Kingston

E. Janssens, G. Demoulin, Institut royal des Sciences Naturelles de Belgique, Brussels

R.E. Lewis, Iowa State University, Ames, Iowa

J.E. Cronin, California

J.F. Brimley, Wellington, Ontario

J.L. Carr, Calgary, Alberta

J.L. Heilman, University of Maryland, College Park, Maryland

J. Schuh Klamath Falls, Oregon

Karl Stephan, Tucson, Arizona

C.L. Hogue, Los Angeles County Museum

J.B. Chapin, Louisiana State University, Baton Rouge, Louisiana

J. Scott, A. Newton, M. Thayer, Museum of Comparative Zoology, Harvard University, Cambridge,
Massachusetts

A. Camousseight, Museo Nacional de Historia Naturale, Santiago, Chile
Hans Reichardt, Cleide Costa, Museu de Zoologia da University de Sao Paulo
V.R. Vickery, McGill University, Montreal, Quebec

R.L. Post, A. Ashworth, North Dakota State University, Fargo, North Dakota

N. M. Downie, Lafayette, Indiana

R.E. Kurczewski, State University of New York, Syracuse
R.L. Westcott, Oregon Department of Agriculture, Salem, Oregon
L. Ryker, Oregon State University, Corvallis, Oregon
C.A. Triplehorn, Ohio State University, Columbus, Ohio

K. R. Valley, Pennsylvania Bureau of Plant Industry

P.D. Perkins, National Museum of Natural History, Washington, D.C.

J. Menier, Museum National d'Historie Naturelle, Paris, France

K. W. Brown, Peabody Museum of Natural History, Connecticut
A. Provonsha, Purdue University, Lafayette, Indiana

Western Hemisphere Hydraenidae

11

RG R. Gordon, Washington, D.C.

RTA R.T. Allen, University of Arkansas, Fayetteville

SC St. Cloud State College, Minnesota

SDSU E.U. Balsbaugh, Jr., South Dakota State University

Sll Staten Island Institute of Arts and Sciences, New York

UA F.G. Werner, University of Arizona, Tucson, Arizona

UBC K.M. Stuart, University of British Columbia, Vancouver

UCB J.A. Chemsak, University of California, Berkeley

UCD R.O. Schuster, University of California, Davis

UCR S. Frommer, University of California, Riverside

UCM U.N. Lanham, University of Colorado Museum, Boulder

UI University of Idaho, Moscow, Idaho

UM M. Coulloudon, University of Montreal, Montreal

UMA P.J. Clausen, University of Minnesota, Minneapolis, Minnesota

UM1 T.E. Moore, University of Michigan, Ann Arbor, Michigan

UNH University of New Flampshire, Durham, New Flampshire

USNM P.J. Spangler, National Museum of Natural History, Washington, D.C.

UW L.J. Bayer, University of Wisconsin, Madison, Wisconsin

UWA S. Rohwer, University of Washington, Seattle, Washington

VMK V.M. Kirk, South Dakota Insect Laboratory

WRS Walter R. Suter, Carthage College, Wisconsin

WSUP W.J. Turner, Washington State University, Pullman.

NATURAL HISTORY

Members of the family Hydraenidae in the Western Hemisphere are most frequently found
at the margins of clear, sandy streams (Figs. 191A,192A). In such habitats they are easily
collected by stirring the sand and gravel at the waterline and waiting for the beetles to float to
the surface, where they remain suspended, upside-down, in the surface film. Since they cannot
swim, these tiny beetles become trapped in the surface film, appearing as silvery specks due to
their ventral air bubble. While in this inverted position, a beetle is able to walk about on the
underside of the surface film, and when near an emergent object the floating beetle is
immediately pulled to the object by surface tension, and rapidly crawls beneath the surface.

In streams of western North America one can frequently find Hydraena, Ochthebius and
Limnebius adults in microsympatry with adults of such hydrophilid genera as Laccobius and
Chaetarthria. Elsewhere (Perkins, 1976) I described a sampling technique which can be used
to study the different microhabitat zones used by these psammophilous aquatic beetles, and
factors which limit their microhabitat distributions. I refer the reader to that paper for details
on this topic, and restrict my comments to more generalized aspects of habitat use by
hydraenids.

Generally speaking, the adaptation of species to margins of lentic habitats, such as ponds,
lakes and rock pools, sees its greatest expression in Ochthebius and allied genera, a decidedly
smaller percentage of Hydraena species being typical of such habitats, whereas New World
Limnebius species are known only from flowing water. Ochthebius is also the only genus of
these three which has species adapted to margins of saline and alkaline aquatic habitats, such
as salt marshes and mineralized hot springs.

Certain other genera are quite specialized in their use of aquatic habitats. Neochthebius
adults are found only in cracks and crevices of intertidal rocks (Figs. 198A-C), whereas
Parhydraenida adults are madicolous and Spanglerina adults live on plant debris trapped
behind emergent rocks in rapid tropical streams (Figs. 196A,B).

Quaest. Ent., 1980, 16 (1,2)

12

Perkins

Although members of Hydraenidae in the Western Hemisphere are less frequently collected
than those of many other families of aquatic insects, they are extremely abundant locally if the
physical conditions are appropriate (e.g., Hydraena anisonycha, Ochthebius attritus,
Limnebius ozapalachicus, among others).

Where along a drainage system hydraenids live, and densities attained by the localized
populations, are determined to a large extent by particle and interstitial space size of shoreline
substrate; if particle size is too small, and consequently also interstitial space size, such as in
muddy areas (or silty streams), hydraenids will usually not be present. Conversely, if the
shoreline substrate consists of large stones and boulders, a few specimens of hydraenids may be
found, but not dense populations (an exception to this statement are those species well adapted
to lentic habitats, such as potholes, which can develop dense populations when conditions are
favorable).

Population densities are also intimately related to slope and permanence of the stream bank
(Perkins, 1976). Relatively permanent streambanks with well sorted particles provide living
space and permanence necessary for larvae to complete their development. Larvae have thin
cuticles, requiring that they be in moist situations. However, hydraenid larvae are not aquatic
in the strict sense, and drown if kept beneath the water’s surface for extended periods. Their
small size makes even a drop of water potentially dangerous in the proper circumstances.

Slope of a streambank, its permanence, and degree of saturation of the psammic zone are all
intimately related. Relatively saturated banks generally have a much lower slope angle and are
much more frequently washed downstream and redeposited, whereas relatively unsaturated
banks are generally much more permanent and have a higher slope angle. Frequent mixing of
particles in the relatively saturated and impermanent banks results in more uniform particle
size and prevents vertical sorting of particles. Relatively permanent banks, however, do not
have the particles mixed frequently and the banks are high enough above the water level of the
stream to allow percolation of rain water and water splashing from the stream, with the
consequent sorting of particles (Perkins, 1976). Along streams and creeks with relatively
permanent, sandy shorelines high population densities of hydraenids are usually encountered
(again, these generalizations do not pertain to species typical of standing water).

My experiences collecting in Mexico and Central America revealed habitat preferences
which were quite unexpected. Specimens of a few hydraenids, including all species of
Spanglerina, were found almost exclusively on leaves and twigs which had become trapped
behind stones in rapid tropical streams and cascades (Figs. 196A,B).

These tropical streams typically have a fast flow rate and lack relatively permanent
sand-gravel banks of moderate slope angle and consisting of well sorted particles. Instead, these
rapid tropical streams generally have large boulders behind which first limbs then leaves and
twigs of the plentiful tropical vegetation become trapped.

Two species of Hydraena have also been found in these Spanglerina type habitats,
Hydraena cuspidicollis and Hydraena geminya, as I have collected the former in association
with Spanglerina ingens and the latter with Spanglerina brevis The common habitat of
Hydraena geminya and Spanglerina perhaps explains the widely separated pro- and mesocoxae
of adults of Hydraena geminya and of the other two species of Hydraena closely related to it
(geminya Subgroup). One of the distinctive characteristics of Spanglerina adults is the widely
spread coxae (Figs. 63A,65B) which, as in the Elmidae, are probably an adaptation to allow the
beetles to cling tightly to leaves and twigs in habitats where water flows rapidly.

Data on the immature stages of Hydraenidae, other than that presented in the section on

Western Hemisphere Hydraenidae

13

phylogeny, will be published separately. More specific natural history data pertaining to adults,
when available, is presented in the individual species sections.

CRITERIA FOR SPECIES LEVEL TAXA

The common notion of reproductive isolation is central to the biological species concept,
which I accept (see Mayr, 1969). In practice, determination of reproductive isolation in most
groups is based almost entirely upon indirect, anatomical evidence. Therefore, although it is
possible to demonstrate reproductive isolation, in actuality it is inferred in most taxonomic
work. However, anatomical features upon which inferences are based when predicting species
limits differ markedly from those used in phylogeny reconstruction in that autapomorphous
characters (unique to a species), which do not provide information for phylogeny
reconstruction, are the primary basis for inferring reproductive isolation. Conversely,
synapomorphic (see Hennig, 1966) anatomical features are most useful in phylogeny
reconstruction, but of little aid when attempting to determine species limits.

In most insect groups, including the Hydraenidae, the taxonomist is provided with a
powerful tool of species limits inference in the male genitalia. In Hydraenidae the aedeagus
provides the single most dependable structure upon which to base species level inferences.
Consequently, I have placed a great deal of emphasis upon this structure and am confident it
justifies the “weighting” it has been given. I have made an attempt, when possible, to not only
display the aedeagal differences between species, but also indicate infraspecific aedeagal
variation (e.g., Figs. 91 A-F, 104,1 13A, etc.). After examination of the adeagus in excess of
5200 males, I am confident of the diagnostic importance of this structure. Other external
characteristics are important and they have been carefully studied and described in detail.
However, the most important features in determining closely related sister-species are provided
by the aedeagus.

Because of the highly diagnostic nature of the male genitalia, I have refrained almost
entirely from describing new species when males were not available. Thus, of the 142 new
species described herein, only four of these are known at present from female specimens alone.
These four species are very distinct externally and have been described because they contribute
significantly to our knowledge of either generic distributions ( Meropathus vectis,
Parhydraenida pentatenkta) or species group phylogeny ( Gymnochthebius maureenae,
Gymnochthebius perlabidus ). Additional species in the genera Parhydraenida , Hydraena,
Ochthebius and Gymnochthebius are apparent in the material studied, but I prefer to await
capture of males before describing these species.

For supraspecific categories, subgenera are recognized only for Ochthebius (see
classification section for rationale). Other aggregates of species (below the generic level) are
ranked in informal categories of “species group”, “species subgroup” or “species complex”. As
is discussed in the classification sections on Hydraena and Ochthebius , subgeneric taxa
recognized by earlier workers are generally found to be linked to one another by transitional
stages, and hence, in this family at least, serve principally to burden the nomenclature.

Quaest. Ent., 1980, 16 (1,2)

14

Perkins

METHODS AND MATERIALS

I have examined more than 21,250 adult New World hydraenids plus a significant number
of specimens from other regions of the globe during this study (see Appendix B). Of the New
World specimens, more than 5,218 males were dissected to remove the aedeagus, and numerous
females were dissected to remove the spermatheca (see following section). To attach beetles to
paper “points”, I used common fingernail polish which dissolves with amyl acetate or fingernail
polish remover. A “Wild M5” stereomicroscope was used throughout the study, and
measurements were made with an ocular micrometer fitted to the microscope.

Dissecting techniques

The aedeagus of hydraenid beetles is best removed by opening the elytra and making an
incision along one side in the tergal-sternal membrane from the fourth to the sixth segments,
plus severing the intersegmental membranes between the third and fourth and between the
sixth and seventh terga. The flap of terga thus formed is then laid back, exposing the abdominal
contents, and the aedeagus is extracted with a fine probe. Once the aedeagus has been removed,
the flap of terga is replaced and the elytra returned to the closed position.

For study of the gut and internal reproductive system, it is generally necessary to remove the
elytra entirely, then make an incision along the length of the pleural membrane so that all of
the terga may be lifted. The gut is severed where it enters the abdominal cavity, and the
intersegmental membrane between the fifth and sixth sterna is ruptured, allowing the
abdominal cavity contents to be removed intact.

Once removed, aedeagus and/or abdominal contents are transferred to glycerin from the
water or alcohol in which the dissections were made. For adeagi dissected in alcohol, the
transfer must be made very rapidly so that partial drying does not occur. Drying allows the
formation of air pockets, which in turn obscure internal structure. Once the sclerites are in
glycerin, this is no longer a problem because of the low evaporative rate.

For storage, aedeagi were placed in a tiny drop of glycerin inside a small glass vial which is
cork stoppered. The vial is then affixed to the pin by inserting the pin through the cork, and the
vial is oriented so that the aedeagus is visible through the upper surface of the vial when the
beetle is being studied. Storage in a vial not only provides protection for the aedeagus, but also
affords a degree of protection for the beetle since some of the glass vial projects slightly beyond
the beetle.

I view the method used by d’Orchymont and some others of gluing the aedeagus by its base
to the corner of the card upon which the beetle is also glued as improper since it places this
singularly important structure in a very precarious position. Additionally, it allows the
aedeagus to dry which makes it very brittle and further subject to damage.

Equally improper is the preparation of permanent slide mounts of aedeagi in this group.
This treatment forces the apical portion to be twisted from its proper place in relation to
surrounding surfaces, resulting also in distortion of the midregion. In addition, oval structures
are flattened, the aedeagus is seen in only one view, and the microslide must be placed in a
collection separate from the beetle, thereby increasing the probability of loss. The results of
distortion by microslide mounting are apparent in the illustration of the aedeagus of Hydraena
insularis d’Orchymont (Fig. 53D). Ochthebius kaszabi Janssens is an example of the problems
that can develop when the holotype aedeagus is slide mounted.

Western Hemisphere Hydraenidae

15

Illustrations

All drawings were made by me. Aedeagi were drawn with the aid of a microprojector, which
presents the specimen’s exact image. Highly asymmetrical structures such as the aedeagi of
hydraenids must be illustrated in two views to allow adequate conceptualization of contours.
Consequently, all of the aedeagal illustrations were made in two views, one dorsal and one of
the left lateral aspect. Additionally, partial drawings were made when slight rotation of the
apical portion provides significant additional information.

The more complex aedeagi of Hydraena, and portions of aedeagi of other genera where
contours are especially well developed and important, are stippled in an attempt to reveal these
contours and internal structures.

All aedeagi are at the same scale to make comparison easy. Representative scale lines are
given for most genera (Figs. 13,18,19,22,72,84,100,138,144). Likewise, all body outline
illustrations, drawn with a camera lucida mounted to the microscope, are at the same scale.

Internal reproductive structures were also drawn with the aid of a microprojector.

MORPHOLOGICAL ANALYSIS

Certain morphological features of various genera in the family are worthy of special
comparative discussion, which is presented here. Morphological features used in the taxonomic
treatment are not treated in detail here, but are discussed and illustrated within each generic
unit under the “Discussion” and “Pronotal features” sections.

Sexual dimorphism

Sexual differences are expressed in several external morphological trends within the family.
Because of the highly diagnostic nature of the male genitalia, these sexual differences assume a
significant practical importance since they permit ready recognition of males.

The apex of the abdomen differs between sexes in all species: males with the last sternum
narrower and the penultimate tergum “wrapped around” the sides of the abdomen so that this
tergum is readily visible from ventral view (Figs. 3A,B,63D); females have the last sternum
broader and the penultimate tergum not wrapped around to the extent seen in males
(Figs. 3D,35C). In addition, males of certain species have the last abdominal segments
elongate, this applies primarily to species of the leechi and marginicollis Groups of Hydraena
(Figs. 54B,63B). However, since males of many species do not have elongate segments, and
because the last sternum and part of the last tergum are concealed in some individuals due to
contraction (Figs. 63A,C), it is convenient to have recourse to other sexual differentiating
structures.

Females of Hydraena and Spanglerina have a row of long setae across the anterior portion
of the fifth abdominal sternum (Figs. 35C,48B); this fringe probably functions to prevent
collapse of the ventral air bubble during oviposition. Males have sparse, random, shorter setae
on this sternum (Figs. 63A-D).

Males of many species of Hydraena and Spanglerina (but not including the circulata Group
of Hydraena other than Hydraena quadricurvipes), have distinctive modifications of the pro-
and metatibiae which take a great many forms, some of which are species specific. Protibiae
are excavated near the apex (Figs. 54G,H) or are swollen in many shapes on the inner surface
(Figs. 61C,D,G,H). The metatibiae of some males are enlarged

Quaest. Ent., 1980, 16 (1,2)

16

Perkins

i

Figs. 2A - F (A) diagrammatic representation of abdominal sclerites of Hydraena d-destina <3. (B) aedeagus, homologues
of sterna 9 and 10 and associated muscles of Ochthebius puncticollis. (C) ventral view of terga 9 and 10 (numbered to left)
and sterna (numbered to right) of Hydraena anisonycha. (D) sterna 9 and 10 and associated membrane of Ochthebius
puncticollis. (E) as above, Hydraena anisonycha. (F) hypothetical hydraenid aedeagus.

(Figs. 32D-G,57C,E,F,61A,B,E,F), or have distinctive “brushes” of setae which are stiff and
therefore do not lie flat against the leg in dry specimens (Figs. 32D-G). The extensive variation
in form of the metatibiae suggests a high mutation rate for genes controlling this structure.
Indeed, the only obvious deformity I have seen in the many specimens of Hydraena studied was
a bifurcate metatibia in Hydraena pontequula (Fig. 63D).

Among the more unusual sexual differences in Hydraena are the highly asymmetrical
middle claws of Hydraena anisonycha males (Fig. 57D) and the stridulatory ridges on the
occiptial area of the head in males of the leechi Group (Fig. 3 ID) (discussed in a later section).

In sharp contrast to Hydraena , males of Ochthebius, Gymnochthebius and related genera do
not display obvious differences in tibiae between sexes and females do not have the distinctive
row of long setae on the fifth abdominal sternum. Instead, males of Ochthebius generally (but
not invariably) have distinctive suction setae on protarsal segments (Figs. 98C,128E).
Additionally, males of many species of Ochthebius and Gymnochthebius have the anterior
margin of the labrum upturned and emarginate. Within the emargination are sensilla of various
shapes, generally trumpet-shaped or spatuliform (Figs. 98B,D,103F,1 1 1 A,1 15B,128D,F).
Females also have these sensilla, but they are less developed and the labral margins are not

Western Hemisphere Hydraenidae

17

upturned at all or to the extent seen in males. The greater development of these sensilla in
males (plus upturned margin which would presumably allow them to be placed closer to. the
object sensed) suggest that they may, at least in part, serve for mate recognition.

Males of Gymnochthebius species have two distinctive, longitudinal rows of setae on the last
abdominal sternum.

Males of many Meropathus species have the labrum extended anteriorly into two
remarkably long processes (e.g., M. campbellensis). The only Western Hemisphere species ( M .
vectis ) is known only from females, but males are expected to possess these processes.

Hydraenida males are easily recognized by large pads of protarsal suction setae.
Parhydraenida males, however, lack these pads of suction setae, but many have the labrum
strongly upturned (Figs. 15B-D) and the abdominal differences between sexes described above
generally are obvious.

Limnebius males are easily differentiated, possessing large pads of suction setae on the pro-
and mesotarsi (Fig. 69C). Additionally, males generally have the elytral apices truncate
slightly, and frequently have a median oval depression on the sixth abdominal sternum.

Aedeagus

In most species of hydraenids the aedeagus is a tubular structure, more or less curved at the
base and has two lateral parameres (Figs. 2F,22A-E,60A-D). It differs from the typical four
lobed (basal piece + median lobe + two parameres) aedeagus of most polyphagan males in
that it lacks (in many species) an obvious, distinct demarcation between basal piece and median
lobe.

Lack of a distinctive demarcation between basal piece and median lobe has prompted some
authors to postulate that the basal piece, as such, is absent from Hydraenidae, and therefore
the entire aedeagus, with the exception of the parameres, consists of a structure homologous to
the median lobe of other beetles. Thus, Crowson (1955) states, “Not the least remarkable
feature of these perplexing insects is their abdominal structure. Assuming that, as is general in
Haplogastran beetles, the first complete visible sternite belongs to the third abdominal segment
and that the second is represented only by lateral pleural vestiges and perhaps some trace in the
middle between the hind coxae, the adult in both sexes would appear to have complete tergites
and sternites up to and including the ninth segment and a distinct tergite for the tenth. The
presence of a distinct ninth sternite seems here, as in the Staphylinidae, to be correlated with
the absence of a basal piece of the aedeagus; in fact it seems quite possible that the basal piece
of the aedeagus is the ninth sternite”.

Specialists in the Hydraenidae, however, have contended that the main tube of the aedeagus
actually represents the basal piece and that the structure at the apex of this heavily sclerotized
tube is homologous to the median lobe of the plesiomorphic state. This terminal structure is
frequently movable (mobile) and structurally very complex. D’Orchymont (1929c) was
apparently the first to present this view, as he compared the hydraenid aedeagus to that of the
hydrophilid, Spercheus : “II se compose d’une partie rigide et fortemont sclerifiee en form de
coin, de forme tres variee, ordinairement en courbe plus or moins prononcee dont la concavite es
dorsale. C’est l’equivalent du lobe basal des Spercheus et des Hydrophilidae ( sensu stricto ); de
a lobe basal a une certain distance de sa base et avant son extreemite se detache a droite un lobe
median....”.

F. Balfour-Browne (1958: 45), after mentioning the comments of d’Orchymont, states, “My
son has come to the same conclusion, that the main-piece is the basal piece and in this I agree”.

Quaest. Ent., 1980, 16 (1,2)

18

Perkins

It is also possible that the basal piece and median lobe have fused. If so, the major portion of
the main-piece could be homologous to the median lobe, and perhaps the terminal or
pre-terminal process of hydraenid aedeagi is homologous to the internal sac of staphylinoids.
This interpretation has its problems, however. For instance, in Limnebius (Figs. 70,71) the
enlarged base has an internal, coiled duct. In addition, the aedeagus has a well developed,
articulated terminal process. If the terminal process is considered the internal sac homologue,
then what is the homology of the coiled duct? If however the coiled duct is considered the
internal sac homologue, then the terminal process could be considered the median lobe
homologue, and the basal portion becomes homologous to the basal piece.

Returning to Crowson’s (1955) suggestion that the basal piece of hydraenids has become the
ninth sternum, I must disagree with this notion since, as is explained further in the following
section on the abdomen, it appears to me that the last abdominal sternum is actually the tenth,
whereas the ninth sternum has become the rod-like, internal strut (Figs. 2A-E) which is
attached to this last sternum. In many males there is a small swelling near the midregion of this
strut, and a minute fragment of membrane attached at this swelling; these possibly represent
the vestiges of the intersegmental membrane which separated the ancestral ninth and tenth
sterna.

Further, large, short muscles join the end of the strut to the base of the aedeagus (Fig. 2B).
If the strut actually represented the basal piece, these strong muscles would therefore be
between the basal piece and the median lobe, a highly unlikely arrangement.

These strong, short muscles connecting the end of the strut and the base of the aedeagus
present an interesting problem, since they are obviously too short to permit protrusion of the
aedeagus beyond the abdominal apex during copulation. Another group of muscles also attach
at the base of the aedeagus, but these muscles are long and originate on the ninth tergum, and
presumably are those which function to extend the aedeagus. One explanation to resolve this
problem is that the slender strut is flexible and bends to permit extrusion of the aedeagus, then
provides the force, due to its elasticity, to return the aedeagus to its position in the abdomen
when the long muscles relax following copulation.

If one looks closely at the short muscles connecting the strut and the aedeagal base
(Fig. 2B), they are seen to be attached to the aedeagus in two groups, one on each side of the
base. Contraction of these muscles, therefore, would not only cause the aedeagus to be very
slightly drawn closer to the end of the strut, but would also cause extensive rotation of the
aedeagus.

How do these muscles function? I have observed Hydraena marginicollis adults during
copulation, and have seen the following sequence in aedeagal extension: 1) the aedeagus
extends in a straight line posteriorly out of the abdomen, until all, or nearly all, of the aedeagus
(except the curved basal portion) is outside the abdomen; 2) the aedeagus tilts upward so that
its apex is pointed dorsally: 3) the aedeagus swings to the left side of the beetle and continues
this arc until it is directly beneath the midline of the abdomen, in the copulatory position. This
sequence of events is followed in reverse during retraction of the aedeagus, but differs in that
retraction is generally more rapid than extension.

Apparently the muscles and strut function in the following manner: 1) at rest in the
abdomen, the aedeagus is dorsal to the strut, with the curved basal portion (and therefore the
basal opening of the aedeagus) directed dorsally (tilted to the side slightly in some species); 2)
the long muscles connecting the aedeagal base and ninth tergum contract, causing the aedeagus
to emerge from the abdomen on a straight line until the curved base reaches the abdominal

Western Hemisphere Hydraenidae

19

apex, and also causing the strut to bend; 3) further contraction of the long muscles cause the
aedeagus to tilt upward so that it points dorsally; 4) one of the two muscle bundles joining the
aedeagus and strut contracts, causing the aedeagus to swing to the side and then ventrally to
the horizontal, copulatory position; 5) following copulation, contraction of the other of the two
short muscle bundles (and concurrent relaxation of the first) connecting the aedeagal base and
the strut returns the aedeagus to the vertical position; and 6) the long muscles relax, permitting
elasticity of the strut to return the aedeagus to the horizontal resting position within the
abdomen.

In Hydraena marginicollis males the slender tube at the apex of the aedeagus (Fig. 5 5 A) is
inserted into the female and the small, slightly elastic globose portion at the base of the slender
tube comes in contact with the tenth tergum of the female. After insertion of the slender tube,
the male pulsates the aedeagus against the female at a frequency of about two pulsations per
second. It seems likely that this pulsation might cause the bulb at the base of the slender tube to
act as a pump mechanism in sperm transfer. Such a bulb is seen in several species of Hydraena-.
Hydraena pontequula (Fig. 60D); Hydraena guatemala , (Fig. 51 A); Hydraena browni,
(Fig. 53A); Hydraena pulsatrix, (Fig. 55C); etc.

I have observed copulation in a number of Hydraena species, and suspect that
parthenogenesis is quite rare in the family, if it exists at all. F. Balfour-Browne (1958), based
upon the bizarre appearance of some hydraenid aedeagi, concluded that parthenogenesis was
widespread in the family, stating (p. 149), “These Hydraena- group beetles, of which some or
many may still be capable of mating, are in the early stage of a process which has gone much
farther in the sawflies, but my son argues against there being any parthenogenesis among them
and relies upon his work with some of the species in aquaria where he was unable to obtain eggs
until he introduced males. He does not, however, claim to have seen the mating and he does not
attempt to explain how the deformed aedeagus of many of the species can make the contact
with the female”, and regarding the four species of British Limnebius (p. 132), “To suggest
that this type of armature is functional is stretching the imagination too far (reference is to
truncatellus and papposus). Even in nitidus, in which the aedeagophore can still be recognized
as trilobed, the aedeagus has such an elaborate expansion at or near the apex that it also is
probably ornamental and otherwise functionless and I regard all our species as
parthenogenetic”.

Ratios of male/female specimens generally are indicative of bisexual reproduction (see
Appendix A for figures). Two exceptions might be Spanglerina brevis and Hydraena
puncticollis , both of which have very low male/female ratios which might be interpreted as
reflecting facultative parthenogenesis. At one locality in Guatemala, near La Tinta (see
Spangler and Perkins, 1977, figure 20), my wife and I collected 85 specimens of S. brevis , all
female. There were also numerous larvae present, indicating excellent biotic potential for the
site. However, the male/female ratio for a locality in Oaxaca, Mexico (see Spangler and
Perkins, 1977, figure 19) approximated that seen in other species. Hydraena puncticollis , and
what appear to be a few closely related, undescribed species, are only represented in collections
by female specimens. Further field study is needed to determine the causes of low, sporadic
male/female ratios in these species.

Males of some species appear to have developed an internal, sclerotized, protrusible tube
which possibly is the primary intromissive portion of the aedeagus. Gymnochthebius males have
an obvious internal sclerotized tube (Figs. 84A-D,88C) which differs in shape from species to
species. I have seen one specimen which has this tube extended (Fig. 85D) and suspect that

Quaest. Ent., 1980, 16 (1,2)

20

Perkins

males of most other species have the ability to extend this tube during copulation (see
discussion section of Gymnochthebius for additional comments). Likewise, Limnebius males
(Figs. 70A,71A,75D) have an internal tube, but it is much different than Gymnochthebius ,
being coiled in the globose base of the aedeagus. As in Gymnochthebius , I have seen only a
single specimen with the tube extended, but suspect it is extended in all species during
copulation.

Males of certain species of Hydraena, such as H. prieto (Fig. 47 A) and H. punctata
(Fig. 44B) have a slender, weakly sclerotized flagellum attached to the terminal portion of the
aedeagus, but it is not known if these structures are retractile. Indeed, the supposition that the
gonopore is located at the apex of these flagella requires verification.

Intraspecific variation in shape of the aedeagus is generally quite slight compared to
interspecific differences . I have illustrated aedeagal morphs where they are significant
{Ochthebius lineatus, Figs. 104,108C,D; Ochthebius discretus, Fig. 134A; Gymnochthebius
fossatus Figs. 91 A-F; etc.). Convergence in shape of the aedeagal “terminal piece” (see below),
which is generally the most species-specific diagnostic portion of the structure, between
distantly related species occurs very infrequently, an example being Ochthebius batesoni and
Neochthebius vandykei (Figs. 143D,146D).

Concerning convergences, one development, loss of parameres, is a commonly derived
condition, appearing in every major phylogenetic lineage within the family (see phylogram,
Fig. 147). Hence, parameres are absent from males of Limnebius (Bilimneus) Hydraena
(Haenydra), and Meropathus. Likewise, J. Balfour-Browne (1976) reported that a species
within the Ochthebius (sensu stricto) lineage (as used herein) also is devoid of parameres.

Partial loss of parameres within certain lineages raises the question of mode of reduction of
these structures. In most species of New World Limnebius the aedeagus has setose
enlargements or patches of setae which probably represent the vestiges of parameres
(Figs. 70A,71A), but these vestiges are located toward the distal end of the “main-piece” (see
below), not near the base, the point of paramere insertion for those aedeagi with well developed
parameres (Fig. 22A).

Likewise, parameres of Hydraena paeminosa males (Fig. 95D) have setose swellings near
the apex of the main-piece, obviously derived from parameres.

Similarly, the aedeagi of Parhydraenida males (Figs. 18A-D) have a very small left
paramere and a spike-like process (which I regard as the remnant of the right paramere - see
discussion section of that genus), both of which are located near the apex of the main-piece, not
attached to the base as in the closely related Hydraenida.

How, then, is paramere loss accomplished, and is the method of reduction the same in the
diverse genera in which this trend is expressed? Two obvious possible modes of reduction come
to mind: 1) loss of the parameres due to reduction in size or the more immediate loss due to
one-step mutation; and 2) gradual fusion of the parameres to the main-piece.

The first explanation appears to apply to Hydraena (Haenydra) species, Ochthebius
lindbergi J. Balfour-Browne (1976; mentioned above), and Meropathus species as males of
these groups have a relatively slender main-piece (no indications of paramere fusion or
remnants of setae) and generally have a small swelling at the base of the aedeagus where
parameres generally originate in other species.

The second explanation, fusion of parameres to the main-piece, might be attributed to those
species of Limnebius whose males have remnants of lobes and patches of setae near the distal
end of the main-piece, the latter being relatively thickened. This mode might also apply to

Western Hemisphere Hydraenidae

21

Parhydraenida, where there is a strong indication of paramere reduction on one side, with the
other paramere showing various degrees of reduction {Parhydraenida paralonga, Fig. 20A;
Parhydraenida reichardti, Fig. 18A; and Parhydraenida lambda , Fig. 18D).

Another explanation might be advanced which relates to the question of the derivation of
the main-piece which was discussed above, i.e., whether this part of the aedeagus is the
homologue of the basal piece or median lobe of other beetles. If one accepts the theory
supported above, as do I, that the main-piece is derived from the basal piece, then it can be
supposed that a lengthening of the ancestral basal piece was necessary to form the heavily
sclerotized, relatively long tube now seen in hydraenids. Therefore, it is possible that in certain
lineages the basal piece elongated distal to the insertion of the parameres, resulting in the
parameres being attached closer to the base of the aedeagus, whereas in other lineages the basal
piece might have elongated proximal to the insertion of the parameres, resulting in parameres
attached near the distal end of the sclerotized tube.

Such evolution of the basal piece might also explain the differences in basic plan of
Gymnochthebius and Ochthebius, as the basal piece in males of the former surrounds the
internal sclerotized tube (presumed homologue of the median lobe) (Fig. 84A), whereas in
Ochthebius males the median lobe (terminal mobile piece) is outside the basal piece and
attached subapically (Fig. 100A).

One cannot deny the great plasticity of the aedeagus in this family, as the illustrations
herein attest. Because of this great variation, I have generally deferred to more descriptive
terminology in reference to the aedeagus, as the hydraenid homologue of the “median lobe” is
generally not median, and the “basal piece” is usually the major portion of the aedeagus
(Fig. 2F). Instead, I have generally used “main-piece” for the basal piece homologue and
“terminal mobile piece” or “terminal piece” for the median lobe homologue (or, as in the case
of Gymnochthebius , the median lobe homologue is termed the “internal tube”).

Abdomen

The abdomen in hydraenids is unusual in a number of respects. First and second terga are
without corresponding sterna (the first tergum is incomplete, represented by two divided,
sclerotized plates). The third tergum, however, does have a sternal counterpart so I assume that
the first complete sternum actually represents the third abdominal segment. Adults of most
genera have a small sclerite between the hind coxae (Fig. 2 ID) which must be derived from the
second abdominal segment (this sclerite is referred to herein as the “intercoxal sternum”).

Counting from the first tergum, therefore, abdominal segments 3-8 are complete and
unambiguous. The sternal counterparts of terga 9 and 10, however, provide a source of
controversy since there is only one obvious sternum which can be associated with the two terga
(Fig. 2A).

As discussed earlier, Crowson (1955) suggested that this small, last sternum was derived
from the ancestral basal piece of the aedeagus. In the previous section on the aedeagus I have
presented my reasons for considering the aedeagus of hydraenids as possessing a basal piece,
therefore, the nature of the last sternum must be explained differently.

This last sternum is unusual in that in males it is prolonged anteriorly into a thin, rod-like
strut (Figs. 2A-E) in the abdomen, joined to the aedeagus by muscles (see previous section).
This strut frequently has a small enlargement near midlength to which attaches a small
fragment of tissue which could be the vestige of the intersegmental membrane separating the
ancestral ninth and tenth sterna. I propose, therefore, that the rod-like strut is the modified

Quaest. Ent., 1980, 16 (1,2)

22

Perkins

ancestral ninth sternum and the last sternum present today is the counterpart of the last
tergum, that is, the tenth.

The manner in which the ninth tergum “wraps around” the abdomen (Figs. 2C,3A,B) in
hydraenid males seems to support this hypothesis since its enlargement ventrally would
presumably be associated with an equal reduction in size of the ninth sternum.

In males of hydraenids, the “wrapped around” portions of the ninth tergum are more
developed than in females and in some groups this apparatus is withdrawn into the abdomen,
being concealed by the sixth visible (true eighth) sternum. Consequently, in these groups
inspection of the ventral surface reveals only six sterna. In other groups, especially those such as
the marginicollis Group of Hydraena in which males have the apical (especially ninth tergite)
segments elongate, the “wrapped around” portion of the ninth tergum plus the last sternum are
clearly visible. Hence, in these groups inspection of the ventral surface reveals seven sterna
(Figs. 63A-D).

In females the “wrapped around” portion of the ninth tergum is much less developed and
the last sternum is larger than in males and is exposed. Hence, females always have seven

Western Hemisphere Hydraenidae

23

visible abdominal sterna (Figs. 35C,48B).

In the species descriptions that follow, sterna are referred to in an anatomical sense,
numbering them beginning with the first complete sternum visible (visible #1, true #3) and
ending with the last visible sternum (visible #7, true #10).

Internal Reproductive System

The male reproductive system of hydraenids (Fig. 4A), which has not been previously
described, consists of paired testes, vasa deferentia, lateral accessory glands, median accessory
gland, ejaculatory duct, and aedeagus.

Each testis is a single mass (Figs. 4D,8A) or two separate masses (Figs. 4B,5A,6C).
Differentiation of sperm tubes is (Figs. 7C,8C) or is not apparent.

Ochthebius and Gymnochthebius males differ from one another in that males of
Gymnochthebius (Figs. 4A,B,D,) have a distinct, globose posterior enlargement of the median
accessory gland and the lateral accessory glands are globose also, whereas males of Ochthebius
(Figs. 5,6A,B) lack a posterior enlargement of the median accessory gland and the lateral
accessory glands are generally tubular. In addition, most Ochthebius males have the proximal
end of the vas deferens enlarged which, presumably, serves as a sperm storage area, whereas in
the Gymnochthebius males studied, the vas deferens is not enlarged at the proximal end, but
empties into the globose anterior enlargement of the median accessory gland where sperm
storage probably occurs. The anterior enlargement of the median accessory gland in
Ochthebius assumes remarkable size in some males ( O . tubus , Figs. 6A,B).

Within Ochthebius, I have studied only a single member of the subgenus Asiobates ( O .
discretus , Fig. 5A), which appears to differ from the nominal subgenus in that the proximal
ends of the vas deferens are not enlarged and the median accessory gland is completely tubular,
lacking an anterior enlargement (males of Ochthebius (sensu stricto) studied include O.
lineatus of the interruptus Group, Fig. 5C; O. californicus of the bisinuatus Group, Fig. 5D; O.
gruwelli and O. tubus of the biincisus Group, Figs. 5B,6A,B).

In Hydraena males, the median accessory gland and lateral accessory glands differ
markedly among species groups. The median accessory gland has an anterior enlargement,
but form of the enlargement and manner in which the enlargement and lateral accessory glands
are joined varies. Unlike Ochthebius males, where the anterior enlargement appears simply a
continuation of the median accessory gland, in Hydraena males the anterior enlargement,
although generally small, appears more as an entity distinct from the median accessory gland,
which generally joins its anterior enlargement at the same location as does the common duct of
the lateral accessory glands (Figs. 7A,C).

In males of Hydraena anisonycha (Fig. 8D), the major glandular region of the median
accessory gland is situated more toward the proximal end, whereas the anterior enlargement is
relatively small. Males of this species are unique among those studied in possession of distinct
lacunae formed by a tight loop of the vas deferens.

Hydraena d-destina males (Fig. 8C), by contrast, have the anterior enlargement of the
median accessory gland very large and quite complex, with the lateral accessory glands
adpressed to its surface, the entire complex mass being topped by a twisted portion of the
median accessory gland. Males of this species are also unusual in form of the sperm tubes,
which are frequently coiled into flat discs.

In Hydraena bituberculata males, (Fig. 8A) the anterior enlargement of the median
accessory gland is well developed, as are the lateral accessory glands.

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Perkins

Figs. 4A - D, Internal reproductive structures. (A) Gymnochthebius nitidus, 3 (testes omitted). (B) G.fossatus, 3. (C)
nitidus, 9. (D) G. clandestinus, 3 (plus abdominal ganglion). (B-D at same scale).

Western Hemisphere Hydraenidae

25

Figs. 5A - D, Male internal reproductive structures. (A) Ochthebius discretus. (B) O. gruwelli. (C) O. lineatus. (D) O.
californicus. (testes omitted from B, C and D).

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Perkins

Figs. 6A - C, Male internal reproductive structures. (A) Ochthebius tubus , specimen from Monterey County, California.
(B) O. tubus, specimen from San Luis Potosi, Mexico. (C) Limnebius sinuatus.

Western Hemisphere Hydraenidae

27

Figs. 7 A - E, Internal reproductive structures. (A) Hydraena atlantica, 6. (B) H. circulata $ (C) H. marginicollis , <3.
(D) H. spangleri <3. (E) H. spangleri, 2. (testes omitted from A, B and D).

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Perkins

Figs. 8 A - D, Internal reproductive structures. (A) Hydraena bituberculata , <?. (B) H. atlantica, 9. (C) H. d-destina, 6.
(D) H. anisonycha, <3 (part of testis illustrated).

Western Hemisphere Hydraenidae

29

In males of Hydraena atlantica and Hydraena circulata (Figs. 7A,B) the anterior
enlargement of the median accessory gland is weakly to moderately developed, the lateral
accessory glands being well developed and united to the anterior enlargement by a common
duct.

The reproductive system of Limnebius sinuatus (Sharp) males (Fig. 6C) is relatively simple,
but differs from the others mentioned in that the vas deferens are quite short and the median
accessory gland is rather elongate, having a distinct, slightly expanded portion between the
highly glandular anterior enlargement and the vas deferens. The lateral accessory glands are
well developed.

Preliminary study suggests that at least some differences are detectable in the male
reproductive system of closely related species. These differences relate to shape of the anterior
enlargement and manner in which the vas deferens and lateral accessory glands join this
enlargement. Thus, in Hydraena circulata and Hydraena atlantica males, differences in this
region illustrated (Figs. 7A,B) are constant in the few specimens of each species studied.
Differences in shape of the lateral accessory glands illustrated, however, are not constant, as
males of Hydraena atlantica with curled apical portions of the lateral accessory glands have
been seen. Differences are also evident between the two males of Ochthebius tubus illustrated
(Figs. 6A,B). These may, in fact, represent two species, as the form from Mexico (Fig. 6B)
differs also in aedeagal structure (see Fig. 124C) from the California form (Figs. 6A,124D).
Further study is needed to determine reliability of internal reproductive structures as indicators
of specific distinction.

The female reproductive system (Figs. 4C,8B,9,10) consists of ovaries (4-6 egg tubes),
bursa copulatrix, spermatheca, spermathecal accessory gland and spermathecal duct. Also
illustrated (Fig. 8B) are the presumed silk producing glands.

Females of New World hydraenids have a sclerotized spermatheca provided with an
accessory gland and connected to the bursa copulatrix by a spermathecal duct. The
spermathecal duct is very short, in Gymnochthebius females, or quite elongate, in Limnebius
females. Generally, the spermatheca has a lightly sclerotized, flexible central region and
muscles connecting the more heavily sclerotized proximal and distal portions (Figs. 9I,10B,H).
Contraction of these muscles presumably causes the central region to flex, thereby acting as a
pump mechanism.

Spermathecae vary considerably in shape between females of most genera, and between
some species groups (cf. G. oppositus and G. germaini. Figs. 9E,I). Females of a few closely
related species differ in spermathecae form, (cf. G. laevipennis G. perlabidus and G.
maureenae. Figs. 93H-J). Such differences between sister-species, however, are exceptional.

Representative spermathecae are illustrated (Figs. 9A-I,10K). The highly convoluted
spermatheca of Meropathus vectis (Fig. 146C) is the most unusual.

Stridulatory Structures

Adults of a number of species in the leechi Group of New World Hydraena (all of the leechi
and alternata Subgroups plus certain species in the scintillabella Subgroup) have a flat,
smooth, generally oval and totally impunctate surface at the midpoint of the anterior pronotal
margin (Figs. 31C,E,G,32B,40D). Viewed with the intense light of the microscope, this
previously unreported structure appears as a small, brassy reflection; hence it is termed a
“scintilla” (Latin for spark). I am grateful to Hugh B. Leech for bringing this structure to my

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Perkins

Figs. 9A - I, Spermathecae of Gymnochthebius species. (A) G. clandestinus. (B) G. topali. (C) G. bartyrae. (D) G.
compact us. (E) G. germaini. (F) G. curvus. (G) G. chilenus. (H) G. tectus. (I) G. oppositus.

Western Hemisphere Hydraenidae

31

Figs. 10A - K, Spermathecae. (A) Ochthebius tubus. (B) O. californicus. (C) O. lineatus. (D) O. crenatus. (E) O.
benefossus (F) O. obscurus. (G) Parhydraenida reichardti. (FI) Spanglerina brevis. (I) Hydraena circulata. (J) H.
arizonica. (K) Limnebius sinuatus.

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Perkins

attention at the outset of this study.

Viewed with the scanning electron microscope, the scintilla is seen to be an extremely thin
shelf above a specialized area on the occipital region of the head (Figs. 31 A,D,32A,C,40A,C).
This region is transverse ridged in males, but these ridges are absent from females. There is
little doubt that these interesting structures function together as a stridulatory device.

Figs. 1 1 A - D. (A) Metacoxal sensillum, Ochthebius tubus. (B) Metacoxal sensillum, Limnebius sinuatus. (C) Metacoxal
sensillum, Parhydraenida reichardti. (D) Surface of eye, P. reichardti.

Presence of debris on each side of the occipital ridges in the specimen of Hydraena arizonica
illustrated (Figs. 32A,C) nicely confirms the supposition that the scintilla is rubbed against
these ridges; absence of debris clearly indicates the area of contact. Absence of ridges from
females suggests that perhaps stridulation functions as a recognition signal between opposite
sexes of a species, rather than merely a warning signal. Apparently females, which have a
smaller scintilla than their respective male counterparts, have either lost the ridges, or the
influence of the genes which cause expression of the scintilla in males is so pervasive that the
scintilla is also formed in females although it is without function (a similar phenomenon with
respect to sexual dimorphism appears in species of Hydraena , such as Hydraena d-destina , in
which the male metatibiae are greatly expanded and the females slightly so).

Western Hemisphere Hydraenidae

33

Interspecific variation in number, spacing and shape of ridges has been seen on the few
species which have been studied with the scanning electron microscope, and I suspect these
differences to result in a different pitch for each species.

Adults of seven species of the leechi Subgroup, the single species of the alternata Subgroup,
plus most of the 17 species in the scintillabella Subgroup, have the scintilla well developed.
Adults of a few species in the scintillabella Subgroup, such as Hydraena exilipes and
Hydraena ozarkensis , have the scintilla very narrow (Fig. 40D). It reaches minimum
expression in Hydraena colombiana adults.

Pronotal sensilla

Adults of Limnebius have four moderately distinctive, short setae near the anterior margin
of the pronotum, and six similarly sized and spaced setae near the posterior margin (Fig. 69 A).
Brown (1932), in his description of L. columbianus, was the first author to mention these setae.
Later, d’Orchymont (1945b) noted that these setae were present in all of the Limnebius
material he had studied, and suggested that perhaps they were of generic significance.

Examination by scanning electron microscopy has revealed these setae on the pronota of
adults of certain species of Hydraena , Parhydraenida , Gymnochthebius, and Ochthebius
(Figs. 15E,F,48C,82C,106C,128A). I have not searched for these setae in all species, but this
preliminary survey indicates that these structures are generally found in adults with relatively
smooth surfaces, but are frequently absent from or obscured in adults with coarsely sculptured
surfaces.

The constant morphological location of these setae and their presence in species from all of
the major phylogenetic lineages indicates that their presence is a plesiotypic character state,
and also suggests that they serve some sensory function. Discovery of these pronotal sensilla in
a sublineage of either the Hydrophiloidea or Staphylinoidea would aid in determining the
phylogenetic relationships of the family Hydraenidae.

Metacoxal sensilla

Adults of Parhydraenida , Hydraena , Spanglerina, Limnebius, Gymnochthebius and
Ochthebius possess a curious, disc-shaped structure on the hind coxa
(Figs. 1 1A-C,16C,21D,57B,65C). This “pad”, a previously unreported morphological feature
of the family, appears to be situated on the hind coxae so that flexure of the metatibia causes
contact between the anterior surface of the metatibia (and/or the trochanter) and the “pad”.

Function of this pad is a matter of conjecture; I can only suggest that perhaps it serves as a
pressure sensor. Water flowing over the beetle (from anterior toward posterior as the insect
faces into the current) would force the body backward slightly, causing the anterior surface of
the metatibia to contact the metacoxal pad sensilla. Pressure on these sensilla might possibly,
therefore, be directly proportional to flow rate and serve to monitor the beetle’s position.
Lateral water flow might cause pressure on only one sensillum, and therefore not only detect
flow rate, but also direction relative to the beetle.

I have not found these sensilla in Meropathus adults (using light microscopy), which may
indicate secondary loss associated with terrestrial habits.

These metacoxal pad sensilla are probably a primitive character for the family, as they are
found in diverse lineages. Discovery of these structures in a sublineage of the Hydrophiloidea or
Staphylinoidea would aid in phylogenetic placement of the family Hydraenidae.

Quaest. Ent., 1980, 16 (1,2)

34 Perkins

KEY TO GENERA OF WESTERN HEMISPHERE HYDRAENIDAE

1 Antenna with eleven articles (Figs. 16B,148B); maxillary palpomeres 2 and 4

subequal in length, 3 about one-half length of 4 (Figs. 16A,148B); venter of

head grooved for reception of antennae (Fig. 16A); South America 2

T Antennae with nine articles (Figs. 69H,148A,C,D); maxillary palpus various,
not as above (Figs. 21 A,69B,128C,148A,C,D); venter of head not grooved for

reception of antennae (Figs. 21 H,128C); North and South America 3

2 (1 ) Pronotum subcordate, sides sinuate near posterior angles (Figs. 15A,17A-H);
elytra with serial rows of punctures in sulcate impressions, intervals costate or
subcostate (Fig. 16F); aedeagus with left paramere inserted near apex, right
paramere absent or reduced to small spike near apex (Figs. 18A-D)

Parhydraenida J. Balfour-Browne, p. 45

2' Pronotum with sides straight near posterior angles (Figs. 12A,C); elytra with
serial rows of punctures not in sulcate impressions, intervals flat or slightly
rounded; aedeagus with both parameres elongate, inserted near base
(Figs. 13 A, B) Hydraenida Germain, p. 40

3 (T) Maxillary palpomere 3 longer and broader than 4 (Figs. 98B,103C,148A);

pronotum with transparent or semi-transparent borders at anterior and posterior
margins, with or without transparent lateral margins also (Figs. 96A-F) .... 4

3' Maxillary palpomeres 3 and 4 subequal in length (Figs. 69B,148D), or with 3
much shorter than 4 (Figs. 48A,148C); pronotum without transparent borders
7

4 (3 ) Elytra interlocked, wings absent; eyes reduced, facets very convex

(Figs. 145A-C,146A,B); pronotum without lateral transparent borders;

intertidal or coastal species 5

4' Elytra not interlocked, wings present; eyes not reduced, facets less convex
(Fig. 103B); pronotum with lateral transparent borders more or less developed

(Figs. 96A-F); primarily fresh or brackish water species 6

5 (4 ) Size large (ca. 2.30 mm long) with well developed dorsal pubescence
(Fig. 146A); aedeagus without parameres; one species from Isla de los Estados

and Falkland Islands Meropathus Enderlein, p. 406

5' Size small (ca. 1.65 mm long) without well developed dorsal pubescence
(Figs. 145A-C); aedeagus with parameres (Fig. 146D); one intertidal species,

found on the Pacific coast from British Columbia to California

Neochthebius d’Orchymont, p. 408

6 (4') Aedeagus with apex of main-piece bifid; single process between lobes, extended
or not beyond main-piece. Parameres longer than main-piece
(Figs. 81 A,B,84A-D). Pronotum of many specimens with sides of sclerotized
part deeply emarginate in both anterior and posterior 0.50; between these
emarginations sides produced in sharp point (Figs. 80A,96B); anterior margin
of pronotum deeply emarginate in front of lateral fossulae; anterior angles
lobate, markedly so in some specimens less so in others (North, Central and
South America). In other South American specimens anterolateral
emargination less developed (Fig. 80C), anterior angles less lobate; in still

Western Hemisphere Hydraenidae

35

others (Fig. 80E) anterolateral emargination very shallow, pronotum similar to
that of some adults of Ochthebius ( sensu stricto). In few adults, angulation
between antero- and posterolateral emarginations very large, exceeding in size
lobe formed by anterior angles of pronotum (Figs. 89D,E); North and Central

America Gymnochthebius d’Orchymont, p. 244

6' Aedeagus with main-piece not bifid at apex; single, preterminal, articulated
process extended beyond apex of main-piece. Parameres shorter than main-piece
(Figs. 100A-D). Pronotum with sclerotized part of diverse forms
(Figs. 96A,C-F), but not with markedly lobate anterior angles as described
above. Pronotum of some specimens very transverse, sides gradually rounded
from anterior angles to behind the middle, then deeply notched (Subgenus
Asiobates , Figs. 133A-F). Pronotum of many specimens with sides sinuate and

convergent to base ( Ochthebius ( sensu stricto), Figs. 1 19A-H)

Ochthebius Leach, p. 292

7 (30 Maxillary palpus with second segment very elongate, much longer than third

(Fig. 148C) 8

T Maxillary palpus with second and third segments subequal in length

(Fig. 148D); sides of body evenly arcuate (Fig. 69A) . . . Limnebius Loach, p. 222

8 (7 ) Pronotum markedly angulate in middle, with median ridge and anterointernal

foveolae (Fig. 65E); labium with depressions near anterior margin (Fig. 65F);
procoxae as widely separated as mesocoxae (Fig. 65D); metacoxae widely

separated (Fig. 65C) Spanglerina , new genus, p. 212

8' Pronotum very weakly to moderately angulate in middle, without a median
ridge and anterointernal foveolae (Figs. 21C,48C,54C); labium without
depressions near anterior margin (Figs. 21H,48E,54D); procoxae closer together
than mesocoxae (Figs. 21D,E,48H,54B); metacoxae usually not widely
separated (Figs. 21D,48D,54B) Hydraena Kugelann, p. 60

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CHECKLIST OF WESTERN HEMISPHERE HYDRAENIDAE

Hydraenida Germain

new species

p. 88

11.

H. petila, new species . .

p. 91

1.

H. ocellata Germain

p. 41

12.

H. mignymixys.

2.

H. robusta, new species .

p. 43

new species

P- 92

13.

H. quadricurvipes.

Parhydraenida J. Balfour-Browne

new species

P- 93

The reichardti Group

14.

H. yosemitensis.

new species

p. 94

1.

P. quadraticeps

J. Balfour-Browne

p. 49

The pennsylvanica Complex

2.

P. bubrunipes.

new species

p. 51

15.

H. pennsylvanica

3.

P. reichardti

Kiesenwetter

p. 96

J. Balfour-Browne

P- 52

16.

H. ancylis, new species

p. 99

4.

P. lambda, new species

p. 54

17.

H. vandykei

5.

P. effeminata

d’Orchymont

p. 100

J. Balfour-Browne

p. 54

18.

H. sierra, new species .

p. 101

6.

P. paralonga.

new species

p. 56

The leech i Group

7.

P. alida

The leechi Subgroup

J. Balfour-Browne

p. 57

8.

P. hygropetrica,

19.

H. leechi, new species . . .

p. 103

new species

P- 57

20.

H. breedlovei.

new species

p. 106

The pentatenkta Group

21.

H. arizonica.

new species

p. 108

9.

P. pentatenkta.

22.

H. bituberculata.

new species

p. 59

new species

p. 1 09

23.

H. scintilla.

Hydraena Kugelann

new species

p. 11 1

The circulata Group

24.

H. canticacollis.

The circulata Complex

new species

p. 1 13

25.

H. scopula, new species

p. 1 1 5

1.

H. circulata.

new species

p. 74

The alternata Subgroup

2.

H. arenicola.

new species

P-75

26.

H. alternata ,

3.

H. occidentalis.

new species

p. 1 16

new species

p. 78

4.

H. tuolumne.

The scintillabella Subgroup

new species

P- 79

27.

H. scintillabella.

The angulicollis Complex

new species

p. 1 18

28.

H. scintillutea.

5.

H. angulicollis

new species

p. 1 19

Notman

p. 82

29.

H. alterra, new species

p. 121

6.

H. appalachicola.

30.

H. terralta, new species

p. 122

new species

p. 83

31.

H. pavicula,

7.

H. nigra Hatch

p. 84

new species

p. 123

32.

H. costiniceps.

The atlantica Complex

new species

p. 124

33.

H. germaini

8.

H. atlantica.

d’Orchymont

p. 126

new species

p. 85

34.

H. colombiana.

9.

H. pacifica.

new species

p. 127

new species

p. 86

35.

H. paraguayensis

10.

H. californica.

Janssens

p. 128

Western Hemisphere Hydraenidae

37

36.

H. plaumanni

new species

P-

169

d’Orchymont

p. 129

67.

H. haitensis.

37.

H. sordida Sharp

p. 1 29

new species

P-

171

38.

H. puncticollis

68.

H. mexicana ,

Sharp

p. 130

new species

P-

171

39.

H. zapatina ,

69.

H. perkinsi Spangler

P-

172

new species

p. 131

40.

H. campbelli.

The jivaro Complex

new species

p. 132

41.

H. exilipes.

70.

H. grouvellei

new species

p. 133

d’Orchymont

p.

174

42.

H. ozarkensis,

71.

H. premordica ,

new species

p. 136

new species

P-

175

43.

H~. maureenae.

72.

H. jivaro , new species . .

P-

176

new species

p. 138

73.

H. anaphora ,

new species

P-

178

The particeps Subgroup

74.

H. hyalina , new species .

P-

179

44.

H. orcula, new species

p. 140

The trinidensis Complex

45.

H. sahlbergi

d’Orchymont

p. 141

75.

H. browni , new species

P-

180

46.

H. particeps ,

76.

H. trinidensis ,

new species

p. 142

new species

P-

182

47.

H. decui Spangler

p. 144

77.

H. insularis

48.

H. guadelupensis

d’Orchymont

p.

183

d’Orchymont

p. 145

49.

H. spangleri ,

The marginicollis Complex

new species

p. 146

50.

H. punctata LeConte

p. 148

78.

H. marginicollis

51.

H. oblio , new species

p. 149

Kiesenwetter

P-

184

52.

H. youngi, new species

p. 150

79.

H. turrialba ,

new species

P-

186

The argutipes Subgroup

80.

H. pulsatrix.

new species

P-

187

53.

H. oaxaca, new species

p. 152

81.

H. longicollis Sharp

p.

190

54.

H. scolops , new species

p. 153

82.

H. peru, new species

P-

190

55.

H. crystallina.

new species

p. 155

The anisonycha Complex

56.

H. mazamitla ,

new species

p. 156

83.

H. anisonycha ,

57.

H. prieto , new species . . . .

p. 157

new species

P-

191

58.

H. argutipes ,

The colymba Complex

new species

p. 158

59.

H. bractea , new species .

p. 1 60

84.

H. colymba ,

60.

H. bractoides ,

new species

p.

193

new species

p. 161

85.

H. nevermanni.

61.

H. cuspidicollis.

new species

P-

195

new species

p. 162

86.

H. malkini.

new species

P-

196

The marginicollis Group

87.

H. pontequula.

The marginicollis Subgroup

new species

P-

198

The mexicana Complex

88.

H. sabella , new species

P-

199

89.

H. d-destina.

62.

H. tucumanica.

new species

P-

200

new species

p. 165

90.

H. barricula.

63.

H. quechua ,

new species

P-

202

new species

p. 166

91.

H. splecoma.

64.

H. limpidicollis.

new species

p.

204

new species

p. 167

65.

H. newtoni, new species

p. 168

66.

H. guatemala ,

Quaest. Ent., 1980, 16 (1,2)

38

Perkins

The geminya Subgroup

92. H. vela , new species p. 206

93. H. chiapa, new species p. 207

94. H. geminya ,

new species p. 209

The paeminosa Group

95. H. paeminosa ,

new species p. 211

Genus Spanglerina, new genus
The ingens Group

1. S', ingens, new species p. 216

2. S. fluvicola,

new species p. 218

The brevis Group

3. S. brevis (Sharp) p. 220

4. S. frondsicola,

new species p. 220

Genus Limnebius Leach

1 . L. discolor Casey p. 227

2. L. richmondi,

new species p. 227

3. L. ozapalachicus,

new species p. 230

4. L. piceus (Horn) p. 230

5. L. alutaceus (Casey) p. 230

6. L. arenicolus,

new species p. 234

7. L. leechi, new species p. 235

8. L. borealis

, new species p. 235

9. L. utahensis,

new species p. 236

10. L. sinuatus (Sharp) p. 236

11. L. angustulus (Casey) p.238

12. L. mitus, new species p. 238

13. L. texanus, new species . p. 241

14. L. aridus, new species p. 241

15. L. mexicanus,

new species p. 243

16. L. octolaevis,

new species p. 243

Genus Gymnochthebius d’Orchymont
The plesiotypus Group

1 . G. plesiotypus,

new species p. 251

2. G. jensenhaarupi

(Knisch) p. 253

3. G. octonarius,

new species p. 254

The germaini Group
The germaini Subgroup

4. G. germaini (Zaitzev) p. 256

5. G. chilenus

(J. Balfour-Browne) p. 257

6. G. clandestinus,

new species p. 258

7. G. tectus, new species p. 261

8. G. curvus, new species p. 262

9. G. bisagittatus,

new species p. 264

10. G. francki (Bruch) p.264

11. G. topali

(J. Balfour-Browne) p. 265

12. G. compactus,

new species p. 267

13. G. peruvianus

(J. Balfour-Browne) p. 268

14. G. bartyrae,

new species p. 270

The reticulatus Subgroup

15. G. reticulatus

(d’Orchymont) p. 271

16. G. reticulatissimus,

new species p. 273

The nitidus Group
The nitidus Subgroup

17. G. nitidus (LeConte) p. 274

18. G. fossatus (LeConte) p. 277

1 9. G. falli, new species p. 28 1

The laevipennis Subgroup

20. G. laevipennis

(LeConte) p. 283

21. G. crassipes (Sharp) p.284

22. G. perlabidus,

new species p. 286

23. G. maureenae,

new species p. 287

The oppositus Subgroup
24. G. oppositus.

new species p. 289

25. G. seminole,

new species p. 290

Genus Ochthebius Leach
Subgenus Ochthebius (sensu stricto)

The interrupt us Group
The interruptus Subgroup

1 . O. pacificus,

new species p. 306

2. O. arenicolus.

Western Hemisphere Hydraenidae

39

new species

p. 307

34. O. obscurus Sharp

p. 372

3.

0. lecontei , new species .

p. 308

35. O. mesoamericanus ,

4.

0. interruptus LeConte

p. 311

new species

p. 373

5.

0. sierrensis.

new species

p. 313

The benefossus Group

The borealis Subgroup

36. O. benefossus LeConte

p. 374

6.

0. lineatus LeConte

p. 314

Subgenus Ochthebius (Asiobates)

7.

0. marinus (Paykull)

p. 318

The discretus Group

8.

0. uniformis.

The discretus Subgroup

new species

p. 321

9.

0. borealis

37. O. discretus LeConte

. p. 377

, new species

p. 322

38. O. hibernus ,

10.

0. kaszabi Janssens

p. 325

new species

p. 381

39. O. orbus, new species .

. p. 382

The rectus Subgroup

40. O. mimicus Brown

p. 383

41. O. putnamensis

11.

0. rectus LeConte

p. 329

Blatchley

. p. 385

12.

0. rectusalsus,

new species

p. 331

The similis Subgroup

13.

0. recticulus.

new species

p. 332

42. O. similis Sharp

. p. 385

The bisinuatus Group

The cribricollis Subgroup

14.

O. bisinuatus ,

43. O. cribricollis LeConte

. p. 388

new species

p. 336

44. O. brevipennis.

15.

0. californicus.

new species

p. 389

new species

p. 338

16.

0. richmondi ,

The reticulocostus Subgroup

new species

p. 339

17.

0. costipennis Fall

p. 341

45. O. apache , new species

p. 391

18.

0. crenatus Hatch

p. 343

46. O. browni, new species

p. 393

19.

0. crassalus.

47. O. mexicanus.

new species

p. 343

new species

p. 394

48. O. reticulocostus ,

The biincisus Group

new species

p. 394

49. O. apicalis Sharp

. p. 397

20.

0. attritus LeConte

p. 346

21.

0. batesoni Blair

p. 349

The puncticollis Group

22.

0. sculptoides.

new species

p. 351

50. O. puncticollis

23.

0. sculptus LeConte

p. 352

LeConte

p. 399

24.

0. tubus , new species .

p. 355

51. O. martini Fall

p. 400

25.

0. alpinopetrus.

52. O. angularidus.

new species

p. 357

new species

p. 402

26.

O. spanglerorum

53. O. leechi

Wood and Perkins

p. 359

Wood and Perkins

p. 403

27.

0. aztecus Sharp

p. 359

28.

0. biincisus ,

Genus Meropathus Enderlein

new species

p. 361

29.

0. gruwelli.

1 . M. vectis, new species

p. 407

new species

p. 365

30.

O. arizonicus ,

Genus Neochthebius d’Orchymont

new species

p. 366

31.

0. madrensis.

1. TV. vandykei (Knisch)

p. 410

new species

p. 366

32.

0. pauli, new species

p. 368

33.

0. mexcavatus ,

new species

p. 368

Quaest. Ent., 1980, 16 (1,2)

40

Perkins

GENUS HYDRAENIDA GERMAIN

Hydraenida Germain, 1901: 531 (type species: Hydraenida ocellata Germain, 1901: 536). - d’Orchymont, 1929: 96. -

J. Balfour-Browne, 1975: 44.

Discussion. - As d’Orchymont (1929) pointed out, the eleven segmented antenna is the
unusual structure of adults of this genus, not the ocelli as Germain(1901) had thought. Also of
significance, but not mentioned by d’Orchymont or J. Balfour-Browne (1975) is form of the
ventral surface of the head, which is grooved laterally for reception of the antennae.
Hydraenida adults share this feature with the adults of Parhydraenida (Fig. 16A) and of the
African genus Coelometopon. A discussion of relationships of Hydraenida are developed more
fully in the section on phylogeny.

Specimens of this genus are still exceedingly rare in collections, although 77 years have
elapsed since its description. In fact, only eight specimens other than those which Germain
studied have been seen by subsequent specialists.

Figs. 12A - C, Body outlines. (A) Hydraenida robusta. (B) Parhydraenida alida. (C) Hydraenida ocellata.

The scant information available about habitat preferences of Hydraenida members consists
of that given by Germain (1901), “de los arroyuelos que bajan por las quebradas de Quillota,
Aculeo, Lo Aquila, etc.”, plus H.P. Brown’s label citation, “tributary to Rio Maule”, the latter
referring to the specimens of H. robusta. These notes suggest that adults of this genus are not

Western Hemisphere Hydraenidae

41

hygropetric as are adults of closely the related Parhydraenida. However, P. Spangler collected
six specimens of H. robusta from a “roadside seep”, a label citation which frequently identifies
madicoles. Further field work is necessary to clearly establish habitat preferences of
Hydraenida species.

Pronotal features. - Pronota of Hydraenida adults (Fig. 12A,C) are similar to those of
Parhydraenida adults (Fig. 15 A) in possession of lateral depressions and lateral fossulae.
Hydraenida adults differ in that the anterior foveae and posterior foveae are not united to form
U-shaped depressions as they are in Parhydraenida adults. Also, the pronotum of
Parhydraenida adults is cordiform whereas that of Hydraenida adults is not.

Diagnosis. - Adults of this genus shares with those of Parhydraenida : 1 ) antennomeres 1 1 ,
(Fig. 16B); 2) grooves on venter of head into which the antennae are inserted, (Fig. 16A); 3)
form of the maxillary palpus (Fig. 16A); 4) form of the metasternum, and most other
characteristics. Differences are in the elytral sculpture, which has the primary serial rows of
punctures very weakly striate-impressed, if at all, and the intervals very slightly rounded. In
Parhydraenida adults the primary rows are sulcate-impressed (Fig. 16F) and the intervals
subcostate or costate. Additionally, pronota of Hydraenida adults have the sides straight at the
rear (Fig 12A,C) whereas the sides are sinuate in Parhydraenida (Fig. 15A,17A-H), forming a
subcordate shape. The aedeagi of Hydraenida males have the parameres attached at the base
and elongate (Fig. 13A,B), whereas those of Parhydraenida males are usually very short and
attached near the apex, the right reduced to a spike or absent (Fig. 18A-D) (refer to the
discussion section of Parhydraenida for further comments).

Description. — Form: Elongate-oval, moderately convex (Fig. 12B, 17A-H) Size: Length 2.00-2.20 mm, width
0.85-0.95 mm. Most females slightly larger than males. Color Dark brown. Head: Moderately punctate, markedly
microreticulate dorsally. Interocular foveae shallow. Interocular tuberculi (ocelli) present. Clypeus transverse, sides
convergent. Labrum with anterior margin weakly upturned in males, shallowly emarginate in females. Maxillary palpus
moderately long, last three segments with approximate ratio of 2:1:2. Mentum trapezoidal, width at base equal length;
microreticulate; anterior margin straight. Genae swollen in midregion, grooved laterally for reception of antennae.
Antennae 1 1 segmented (6 + 5). Thorax: Pronotal sides straight at rear. Anterior margin markedly bisinuate, middle 0.20
straight or nearly so, anterior angles produced. Lateral depression with moderately impressed longitudinal fossula, strongly
microreticulate. Disc with two pairs of moderately impressed foveae, anterior pair joined to one another by shallow
depression. Posterior margin of pronotum slightly arcuate to rear in midregion. Prosternum slightly elevated transversely,
coxae contiguous. Metasternum entirely hydrofuge pubescent, longitudinally depressed in midline. Elytra: Disc with six
rows of small punctures, each puncture with a seta; rows very slightly striate-impressed near suture, not striate elsewhere.
Intervals rounded slightly or flat, nearly three times width of primary serial punctures; each interval with row of punctures
nearly equal in size to those of primary rows; each puncture with seta subequal to those of primary rows. Declivity
beginning near posterior 0.33. Explanate margin weakly developed. Abdomen: Basal four sterna and anterior 0.25 of fifth
sternum hydrofuge pubescent, remainder shiny, finely sparsely pubescent. Legs: Of moderate length and build. Genitalia:
Aedeagus with parameres attached near base.

1 . Hydraenida ocellata Germain
(Figs. 12C,13B,14A)

Hydraenida ocellata Germain, 1901: 531 (lectotype male deposited in MHNC; type-locality: Quillota, Chile). -

d’Orchymont, 1929:96. -J. Balfour-Browne, 1975:44.

A lectotype for this species has been designated by J. Balfour-Browne (1975).

Diagnosis. - Adults of this species are slightly smaller and have the dorsal microreticulation
slightly more developed than have adults of the very similar H. robusta. The only totally
reliable means of differentiating these two species is by referral to the remarkably dissimilar
aedeagal forms (Figs. 13A,B)of males.

Description. — Form: Elongate, oval, moderately convex (Fig. 12C). Size: Approximately 2.00 mm long, 0.85 mm
wide. Color Dark brown. Head: Length 0.38 mm; width 0.56 mm. Frons markedly microreticulate, punctures obsolete.

Quaest. Ent., 1980, 16 (1,2)

42

Perkins

Figs. 13A - B, Aedeagi of Hydraenida species. (A) H. robusta , holotype. (B) H. ocellata.

interocular foveae shallow, width of each nearly 0.66 distance separating them; interocular tuberculi large; basomedial
fovea absent. Frontoclypeal suture bisinuate. Clypeus length slightly less than 0.50 width; markedly microreticulate.
Labroclypeal suture straight. Labrum length 0.50 width, strongly microreticulate; anterior margin weakly emarginate,
but weakly upturned margin gives the appearance of a nearly straight anterior edge in habitus view. Maxillary
palpomere 4 (apical) slightly longer than 2 (pseudobasal); palpomere 3 about 0.50 length of 4. Mentum trapezoidal,
width at base equal length; microreticulate finely punctate,; anterior margin straight. Submentum punctulate. Genae
swollen, dull, punctulate, grooved laterally. Postgena finely punctulate. Thorax: Pronotum length at midline 0.46 mm;
maximum width (near anterior 0.33) 0.76 mm. Anterior margin bisinuate, anterior angles produced. Lateral depressions
markedly microreticulate, punctures nearly obscured by microreticulation; sides not apparently crenulate, straight from
near anterior 0.33 to posterior angles. Lateral fossulae very shallow, with same sculpture as lateral depressions. Pronotal
disc markedly microreticulate, densely punctate, dull except for small shiny area in midline slightly behind middle; with
anterior and posterior pair of moderately impressed foveae, anterior pair joined to one another by shallow depression.
Posterior margin weakly arcuate to rear in midregion. Prosternum slightly elevated along anterior margin; coxae
contiguous. Metasternum longitudinally impressed at midline, entirely hydrofuge pubescent. Elytra: Length 1.36 mm;
maximum width (near midlength) 0.85 mm. Disc shiny, much more reflective than pronotum. shallowly depressed in
midregion, with six rows of small punctures between suture and humeri, rows extremely slightly striate impressed on
disc; each puncture with short seta. Intervals flat or very slightly rounded, nearly three times width of punctures in
shallow striae; each interval with row of punctures nearly equal in size to those of primary rows; each puncture with
seta subequal to those of primary rows. Declivity beginning near posterior 0.33. Explanate margin slightly developed.
Abdomen: Basal four sterna and anterior 0.25 of fifth sternum hydrofuge pubescent, remainder shiny, finely sparsely
pubescent. Legs: Of moderate length and build. Genitalia: Male (Fig. 13B) (1 examined).

Natural History. - Germain (1901) states: “Este insecto es anchamente oblongo i
deprimido; i se halla, por los meses de verano, pegado en la parte inferior de las piedras medio

Western Hemisphere Hydraenidae

43

sumerjidas de los arroyuelos que bajan por las quebradas de Quillota, Aculeo, Lo Aguila, etc.”.

Distribution. - (Fig. 14A). Central Chile, in Valpariso Province (Quillota) and, according
to J. Balfour-Browne (1975) Santiago Province (Aculeo and Hospital).

Remarks. - It is remarkable that neither d’Orchymont (1929) nor J. Balfour-Browne
(1975) nor myself have seen specimens other than those which were before Germain at the time
of the original description (1901).

2. Hydraenida robust a new species
(Figs. 12A,13A,14A)

Type-locality. - Tributary to Rio Maule, Maule Province, Chile.

Type-specimens. - The holotype male is deposited in USNM. This specimen was collected
by Harley P. Brown on November 2, 1971. The allotype, collected by H.P. Brown on November
1, 1971, is from Colchagua Province, e. Aguas Buenas, and is also deposited in USNM. One
male and one female paratype from Valpariso Province, Quillota (originally part of Germain’s
type series of H. ocellata ), are deposited in MHNC. Six paratypes (three of each sex) deposited
in USNM have the following data: Chile, Bio-Bio Prov., Santa Barbara (1 km S.) roadside
seep, 25-Jan.-1978, P.J. Spangler.

Diagnosis. - Males of this species are distinguished from those of H. ocellata by
differences in the aedeagus. Females of the two species cannot be distinguished from one
another by structural characteristics.

Description. — Form: Elongate oval, moderately convex (Fig. 12A). Size: Holotype 2.20 mm long, 0.92 mm wide.
Color Head and pronotum dark brown, remainder brown. Head: Length 0.40 mm; width 0.62 mm. Frons markedly
microreticulate, punctures nearly obscured; interocular foveae shallow, width of each nearly 0.66 distance separating
them; interocular tuberculi large; basomedial fovea shallow, transverse. Frontoclypeal suture bisinuate. Clypeus length
slightly less than 0.50 width; small anteromedial area shiny, remainder dull, markedly microreticulate. Labroclypeal
suture straight. Labrum length 0.50 width; markedly microreticulate, moderately densely pubescent; anterior edge
straight, upturned. Maxillary palpomere 4 (apical) slightly longer than 2 (pseudobasal); palpomere 3 0.50 length of 4.
Mentum trapezoidal, concave, width at base equal length; microreticulate, finely punctate; anterior margin straight.
Submentum concave, markedly microreticulate. Genae swollen, dull, punctulate, grooved laterally for reception of
antennae. Postgena punctulate. Thorax: Pronotum length at midline 0.50 mm; maximum width (near anterior 0.33)
0.82 mm. Anterior margin bisinuate, anterior angles produced. Lateral depressions markedly microreticulate, moderately
punctate; sides apparently. not crenulate, or extremely finely so, straight from near midlength to posterior angles. Lateral
fossulae with sculpture as lateral depressions. Pronotal disc markedly microreticulate, densely punctate, dull except for
shiny relief in middle; with an anterior and a posterior pair of well impressed foveae, the anterior pair joined one to the
other by a shallow depression to form a V-shaped figure. Posterior margin arcuate to rear in midregion. Prosternum very
slightly elevated in midline; coxae contiguous, metasternum longitudinally depressed in midline, entirely hydrofuge
pubescent. Elytra: Length 1.48 mm; maximum width (near midlength) 0.92 mm. Disc shiny, much more reflective than
pronotum, shallowly depressed in midregion, with six rows of small punctures between suture and humeri, rows extremely
slightly striate impressed; each with a distinctive short seta. Intervals flat or very slightly rounded, nearly three times width
of punctures in shallow striae; each interval with a row of punctures about 0.50 the size of punctures in primary rows; each
puncture with a seta subequal in size to those of primary rows. Declivity beginning near posterior 0.33. Explanate margin
weakly developed. Abdomen: Basal four sterna and anterior 0.25 of fifth hydrofuge pubescent, remainder shiny, finely
sparsely pubescent. Legs: All legs of moderate length and build. Protarsi with large pad of suction setae on basal three
segments. Mesotarsi also apparently with suction setae on basal three segments, although not forming pads. All claws with
a small tooth on lower surface near base, those of protarsi slightly larger than others. Genitalia: Male (Fig. 13A) (two
examined).

Variation. - Females lack pro- and mesotarsal suction setae and do not have the anterior
margin of the labrum upturned.

Distribution. - (Fig. 14A) Central Chile, in the provinces of Valpariso, Colchagua, Bio-Bio,
and Maule.

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Figs. 14A - B, Geographical distributions. (A) Hydraenida robusta • and H. ocellata ★.(B) Parhydraenida reichardti
• and P. effeminata ★ .

Western Hemisphere Hydraenidae

45

Etymology. - Latin, robusta (strongly built). I refer to the very stout aedeagus.

Remarks. - J. Balfour-Browne (1975) illustrated the aedeagus of a species of Hydraenida
which he preferred not to describe because the adult body had been fragmented due to
“treatment with caustic potash”. The illustration he provides agrees well with that of H.
robusta except for the shape of the apical piece; it seems likely that the caustic potash
mentioned above deformed the aedeagus of his specimen.

GENUS PARHYDRAENIDA J. BALFOUR-BROWNE

Parhydraenida J. Balfour-Browne, 1975:39 (type species: Parhydraenida reichardti, 1975: 40).

Discussion. - This interesting genus was recently described by J. Balfour-Browne (1975) for
four species of hydraenids found in the mountains of southeastern Brazil. In justifying
establishment of this genus, Balfour-Browne states, “By the 11 -segmented antennae, distinct
ocelli and most other characters this group might well be attached to Hydraenida Germain but
the almost cordate pronotum and the absence of aedeagal parameres demand that they be
separated therefrom.”

Close inspection of the aedeagus, however, reveals that it invariably has a left paramere, and
most have a spike-like process which I regard as a remnant of the right paramere. This is true
for the three species Balfour-Browne described (one species is known only by females) and for
the four new species described herein.

The left paramere has apical setae, typical for this structure, in all species except one, P.
lambda. In this species the left paramere is greatly reduced in size (Fig. 18D) and somewhat
spike-like. It is the shape of the left paramere in P. lambda males that suggests that the other
spike-like process, near the apex of the aedeagus, is the vestigial right paramere. This proposed
vestigial, spike-like paramere characterizes males of the following four species: P. reichardti , P.
lambda , P. quadraticeps, and P. hygropetrica. The aedeagus of P. bubrunipes males has a
setose swelling near the apex which is probably derived, at least in part, from the right
paramere (Fig. 19).

P. paralonga males have a relatively long left paramere, about 0.33 the total length of the
aedeagus (Fig. 20A). In males of other species this paramere is much smaller relative to
aedeagal length.

In contrast to the parameres of Hydraenida , however, those of Parhydraenida are inserted
near the apex of the aedeagus and are very short; those of Hydraenida are long and inserted
near the base (Figs. 13A,B). Additionally, the aedeagus of Hydraenida males is straight,
whereas that of Parhydraenida males appears to be twisted. This twisting is reflected in the
shape of the aedeagal base where the ejaculatory duct enters, which is displaced to the left.

The subcordate pronotum emphasized by Balfour-Browne has been found to be consistently
present in the adults of the new species described herein. Additionally, all of the known adults
have the elytral series sulcate impressed, which presents a much different appearance from the
elytra characteristic of the two species currently known for Hydraenida. Based upon the
aedeagal differences, mentioned above, plus the pronotal and elytral differences, I am
considering this group worthy of generic status.

However, area and habitats which remain to be sampled in South America are so very
extensive, and the morphological gap separating these two genera is so narrow, that the
probability of intermediates being discovered would appear to be less than remote.

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Figs. 15A - F, Parhydraenida reichardti, 6. (A) head and pronotum (AUD = anterior U-shaped depression, LD =
lateral depression, LF = lateral fossula, PUD = posterior U-shaped depression). (G) anterior aspect of head. (C,D)
labral emargination. (E) ocelli and anteromedian region of pronotum (arrows indicate pronotal sensilla). (F)
posteromedian region of pronotum.

Western Hemisphere Hydraenidae

47

Figs. I6A - F, Parhydraenida reichardti, 6. (A) head, lateral aspect, (arrow indicates antennal groove). (B) antenna. (C)
metasternum. (D) mesosternum. (E) abdomen. (F) elytra.

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Perkins

Judging from the unusual hydrofuge pubescence of P. pentatenkta adults from Ecuador,
which is geographically quite removed from the remaining eight species of southeastern Brazil,
even the discovery of the male of that species will add considerably to our knowledge of the
genus.

I have seen two females of a species from Paraguay, which suggests that further collecting
may eventually provide geographical intermediates between the southeastern Brazilian and
Ecuadorian components of Parhydraenida. These two females probably represent an
undescribed species. However, they are not sufficiently distinct to warrant formal description
without the diagnostic features of the aedeagi that males would provide. Based upon ventral
pubescence, these two females are members of the reichardti Group.

Pronotal Features. - The major relief features of Parhydraenida pronota (Fig. 15 A) consist
of an anterior (AUD) and posterior (PUD) U-shaped depression, rather broad lateral
depressions (LD), and lateral fossulae (LF). In adults of most species the posterior U-shaped
depression does not join the lateral fossulae, and the lateral fossulae are not divided into distinct
anterior and posterior foveae (Figs. 17F-H). P. reichardti adults (Figs. 15A,17C), however, are
an exception in both respects. Infrequently, as in adults of P. effeminata (Fig. 17E), the
pronotal sculpture is very obsolete, with only a suggestion of the depressions seen in the other
species.

Diagnosis. - Combination of eleven segmented antennae (Fig. 16B) and form of the
maxillary palpus, which has the apical (fourth) segment about twice as long as the third and
subequal that of the second (pseudobasal) (Fig. 148B), readily distinguish Parhydraenida
adults from all those of New World genera of Hydraenidae except Hydraenida. Adults of these
two genera are also unique in form of the ventral surface of the head, which is grooved laterally
for reception of the antennae (Fig. 16A). The subcordate pronotum of Parhydraenida adults
(Figs. 15A,17A-H), plus sulcate impressed elytral series (Fig. 16F) and aedeagal form, which
has the left paramere inserted close to the apex and the right paramere absent or reduced to a
spike, serve to distinguish them from adults of Hydraenida. In Hydraenida adults the pronotal
sides are straight in the rear, the elytral series are not sulcate impressed, and the aedeagus has
two long parameres which insert near the base.

Description. — Form: Generally elongate-oval, some adults somewhat truncate (Figs. 17A-H), moderately convex.
Size: Length 1.50 to 2.20 mm, width 0.68 to 1.05 mm. Most females slightly larger than males. Color Most adults black, a
few brown. Head: Moderately finely punctate to rugulose, generally with well developed microreticulation dorsally.
Interocular foveae moderately to well developed. Interocular tuberculi (ocelli) prominent. Clypeus transverse, parallel
sided to convergent anteriorly, some specimens with anterior angles deflexed. Labrum commonly with anterior margin
straight and upturned in males, remarkably so in some species; females shallowly emarginate. Maxillary palpus
moderately long, last three segments with approximate ratio of 2:1:2. Mentum trapezoidal, width at base approximately
equal to length; generally finely microreticulate; anterior margin straight. Genae swollen in midregion, grooved laterally
for reception of antennae. Antennae 1 1 segmented (6 + 5). Thorax: Pronotum with sides weakly to moderately sinuate at
rear, subcordate in shape. Anterior margin very slightly to moderately bisinuate in habitus view, trisinuate in anterior
view, anterior angles generally produced. Lateral depressions of most adults with moderately impressed fossula between
lateral depression and disc, fossula infrequently interrupted in midlength in form of two separate depressions ( reichardti );
area between fossula and side of pronotum generally slightly convex; sides crenulate. Disc with two U-shaped depressions,
well formed in most adults; posterior extremely shallow in few adults, generally well formed, in few adults joined to lateral
fossulae by shallow depression; anterior U-shaped depression extended to anterior margin of pronotum, deepest near
anterior margin in many adults. Posterior margin of pronotum arcuate to rear of midregion. Prosternum of most adults
elevated in midregion, not carinate; anterior coxae contiguous. Metasternum entirely hydrofuge pubescent, longitudinally
depressed in midline. Elytra: Disc with six rows of deeply impressed punctures between suture and humeri, each puncture
with prominent seta; rows weakly to markedly sulcate impressed. Intervals subcostate to costate, each with row of
setiferous punctures, punctures smaller than those of primary rows; first interval extended to apex in some adults,
terminated near apical 0.25 in others. Explanate margin moderately developed. Sides at anterior angles serrate. Abdomen:
Generally with basal four sterna plus anterior 0.25 of fifth sternum hydrofuge pubescent, remainder shiny. Hydrofuge
pubescence in few specimens restricted to first two sterna plus anterior 0.25 of third ( P . pentatenkta). Legs: Of moderate

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49

length, rather stout, without apparent sexual dimorphism. Genitalia: Aedeagus with left paramere, although very small
in many males, inserted near apex; right paramere absent or reduced to spike-like process, inserted near apex.

Key to Western Hemisphere species of Parhydraenida

1 Hydrofuge pubescence of abdominal sterna restricted to basal two plus anterior

portion of third, remaining sterna shiny, very sparsely pubescent; Ecuador
(Fig. 17B) P. pentatenkta, new species, p. 59

V Hydrofuge pubescence on sterna 1-4 plus anterior portion of fifth; southeastern

Brazil 2

2 (1') Clypeus with parallel sides P . quadraticeps J. Balfour-Browne, p. 49

2 ' Clypeus with convergent sides 3

3 ( 2') Lateral fossulae of pronotum discontinuous, divided by elevated portion of

lateral depressions in form of deep depression near each angle of pronotum

(Figs. 15A,17C) P. reichardti J. Balfour-Browne, p. 52

3' Lateral fossulae not discontinuous 4

4 ( 3') Large, ca. 2.20 mm long; brownish; fifth abdominal sternum with transverse

band of short setae; clypeus markedly transverse (Figs. 17H, 19)

P. bubrunipes , new species, p. 51

4' Smaller, ca. 1.90 mm long or less; blackish; fifth abdominal sternum with

sparse, random setae; clypeus not markedly transverse 5

5 (4') Elytron with first interval (from suture) extended to just slightly before apex . 6

5' Elytron with first interval ending near posterior 0.25 7

6 ( 5 ) Pronotum with posterior U-shaped depression well developed (Figs. 17G,18D)

P. lambda , new species, p. 54

6' Posterior U-shaped depression absent or nearly imperceptible (Fig. 17E)

P. effeminata J. Balfour-Browne, p. 54

7 (50 Pronotal reliefs moderately shiny, punctate, not microreticulate (Figs. 12B,20B)

P. alida J. Balfour-Browne, p. 57

7' Pronotal reliefs dull, microreticulate 8

8 ( 70 Elytral rows deeply sulcate impressed; size larger, ca. 1.72 mm long; aedeagus

as illustrated (Figs. 17D, 20A) P. paralonga, new species, p. 56

8' Elytral rows shallowly sulcate impressed; size smaller, ca. 1.52 mm long;

aedeagus as illustrated (Figs. 17F,18B)

P. hygropetrica, new species, p. 57

1. Parhydraenida quadraticeps J. Balfour-Browne
(Figs. 17A,18C,162)

Parhydraenida quadraticeps J. Balfour-Browne, 1975:42. (holotype male, unique, deposited in MSP; type-locality:

Morretes, Parana, Brazil).

Diagnosis. - The parallel sided clypeus and aedeagal form serve as diagnostic features for
this species. The strongly upturned labrum of males is also distinctive.

Description. — Form: Slightly truncate, moderately convex (Fig. 17A). Size: Holotype 1.76 mm long, 0.78 mm
wide. Color Dorsum and venter black; legs, palpi and antennae brown. Head: Length 0.40 mm; width 0.52 mm. Frons
finely microreticulate, moderately coarsely punctate in middle, very sparsely pubescent; interocular foveae moderately
deep, subrugulose, width of each 0.66 distance between them; interocular tuberculi prominent; basomedial foveae absent.
Frontoclypeal suture evenly arcuate. Clypeus length 0.33 width, sides parallel; anterior angles prominent, rounded;

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Figs. 17A - H, Parhydraenida species, body outlines. (A) P. quadratieeps. (B) P. pentatenkta. (C) P. reichardti. (D) P.
paralonga. (E) P. effeminata. (F) P. hygropetrica. (G) P. lambda. (H) P. bubrunipes. (to same scale).

sculpture as frons. Labroclypeal suture slightly arcuate to rear. Labrum length nearly 0.33 width; anterior margin
straight, strongly upturned along entire width; sculpture as clypeus, although slightly more pubescent. Maxillary
palpomere 4 (apical) slightly longer than 2 (pseudobasal); palpomere 3 shorter than 2. Mentum trapezoidal, width at
base equal length, dull, finely microreticulate, very finely punctulate, anterior margin straight. Submentum finely
microreticulate, finely punctulate. Genae dull, finely microreticulate finely punctulate, swollen; grooved laterally for
reception of antennae. Postgena finely punctulate. Thorax: Pronotum length at midline 0.42 mm; maximum width (near
anterior 0.33) 0.68 mm. Anterior margin shallowly bisinuate. Lateral depressions slightly convex, coarsely punctate,
each puncture with short seta, finely microreticulate; sides crenulate, sinuate, not strongly produced laterally. Lateral

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51

fossulae much deeper at anterior and posterior extremes, in form of four large foveae, posterior slightly larger than
anterior. Pronotal disc rounded, sculptured as lateral depressions, with anterior and posterior, wide U-shaped depression;
anterior depression extended to anterior margin; posterior depression with “arms” terminated on disc, clearly separated
from lateral fossulae by convex area on each side of disc. Posterior margin of pronotum arcuate posteriorly in
midregion. Prosternum elevated in midline, not carinate; coxae contiguous. Metasternum with large, longitudinal,
median depression; entirely hydrofuge pubescent. Elytra: Length 1.06 mm; maximum width (near midlength) 0.78 mm.
Disc shallowly depressed in middle, shiny, with six rows of large, deep punctures between suture and humeri, rows
sulcate impressed. Declivity in posterior 0.33. Intervals subcostate, width less than puncture width; each with row of
decumbent setae; first interval (from suture) extended to apex. Explanate margin moderately developed, terminated
near posterior 0.25. Apices slightly truncate. Abdomen: Basal four sterna with hydrofuge pubescence. Sternum 5
hydrofuge pubescent in anterior 0.33, remainder shiny. Sternum 6 shiny, very sparsely pubescent, posterior margin
arcuate to anterior in midline. Apical segment shiny, very sparsely pubescent. Legs: Moderately short and stout.
Genitalia: Male (Fig. 18C) (one examined).

Variation. - I have tentatively identified two females, with the following data, as P.
quadraticeps : Morretes, PR, km 37, Est. da Graciosa, Rio Cascata, 20-VI-1975,
H. & B. Reichardt. The pronotal and elytral features of these females agree very well with
those of the holotype. The sides of the clypeus, however, are slightly, but distinctly convergent,
not parallel as in the holotype male. The labrum is emarginate and not strongly upturned.
When series consisting of both sexes become available, they will probably reveal that the
differences in clypeal shape are sex-associated as are differences in the labrum.

Distribution (Fig. 162). - Known only from the type locality, Morretes, Parana, Brazil.

Remarks. - In the original description, J. Balfour-Browne (1975) states that the labrum has
the “anterior edge in males straight, strongly raised with a sharply impressed transverse
impression immediately behind....”. By way of clarification, although the markedly upturned
anterior margin forms a sharp angle with the remainder of the labrum, there is, however, no
transverse sulcus distinct from the sloping, basal portion of the labrum.

2. Parhydraenida bubrunipes new species
(Figs. 17H,19,162)

Type-locality. - Nova Teutonia, Santa Catarina, Brazil.

Type-specimen. - The holotype male (unique) is deposited in MCZ. Fritz Plaumann
collected this specimen in February, 1954.

Diagnosis. - Large size (2.20 mm long), brown color and strongly transverse clypeus are
diagnostic features for this species. Additionally, the holotype is unique among the known
species of Parhydraenida in possession of a transverse band of short setae on the fifth
abdominal sternum in males, at least; females are unknown.

Description. — Form: Elongate oval, moderately convex (Fig. 17H). Size: Holotype 2.20 mm long, 1.04 mm wide.
Color: Dorsum and venter dark brown; legs bright brown, contrasting well with venter; palpi teslaceus in basal 0.50, apical
0.50 dark brown. Head: Length 0.40 mm; width 0.66 mm. Frons in middle coarsely closely punctate, interstices shining,
very finely microreticulate, very sparsely pubescent; interocular foveae subrugulose, deep and large, width of each nearly
0.66 distance separating them; interocular tuberculi prominent; basomedial fovea absent. Frontoclypeal suture evenly
arcuate. Clypeus length slightly less than 0.33 width, sides slightly convergent, anterior margin arcuate to rear, anterior
angles prominent, rounded; surface subrugulose; viewed anteriorly fr-ont edge of clypeus markedly arcuate. Labrum length
0.33 width; anterior margin moderately upturned, arcuate in habitus view. Maxillary palpomere 4 (apical) slightly longer
than 2 (pseudobasal); palpomere 3 slightly less than 0.50 length of 4. Mentum trapezoidal, dull, finely microreticulate.
Submentum finely microreticulate. Genae swollen, shiny in midregion, microreticulate and grooved laterally for reception
of antennae. Postgena finely punctulate. Thorax: Pronotum length at midline 0.50 mm; maximum width (near midlength)
0.90 mm. Anterior margin bisinuate in habitus view, trisinuate in anterior view. Lateral depressions convex, coarsely
closely punctate, each puncture with a short but very apparent seta, finely microreticulate; sides crenulate, sinuate,
strongly produced laterally. Lateral fossulae sinuate, posterior portion slightly deeper than remainder. Pronotal disc
sculptured as lateral depressions, with anterior and posterior U-shaped depression; anterior U-shaped depression extended
to anterior margin, anterior extremes connected to anterior portion of lateral fossulae by shallow depression; posterior

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U-shaped depression with “arms” terminated on disc, not connected to lateral fossulae. Posterior margin arcuate to rear
in midregion. Prosternum elevated in midline, not carinate; coxae contiguous. Metasternum broadly depressed in
midregion, hydrofuge pubescent except for very small, shiny area anterior to and between posterior coxae. Elytra:
Length 1.40 mm; maximum width (near midlength) 1.04 mm. Disc shiny, broadly depressed in middle, with six rows of
large, deep punctures between suture and humeri, rows sulcate impressed. Declivity extended through posterior 0.33.
Intervals costate, width slightly less than puncture width; first interval (from suture) extended to apices. Explanate
margin well developed, ending near apical 0.16. Apices slightly truncate. Abdomen: Basal four sterna with hydrofuge
pubescence. Sternum 5 hydrofuge pubescent in anterior 0.16, middle of sternum with transverse band of short setae in
very shallow depression. Sternum 6 shiny, sparsely pubescent, posterior margin arcuate to front in midregion. Apical
segment shiny, sparsely pubescent. Legs: Moderately long and stout. Genitalia: Male (Fig. 19) (one examined).

Distribution (Fig. 162). - Known only from the type locality of Nova Teutonia in the state
of Santa Catarina, Brazil.

Etymology. - Latin, bu (large) plus brun (brown) plus ipes (foot). I refer to large size and
brownish legs which contrast well with the remainder of the venter of the holotype.

3. Parhydraenida reichardti J. Balfour-Browne

(Figs. 1 0G, 1 1 C,D, 1 4B, 1 5 A-F, 1 6 A-F, 1 7C, 1 8 A, 1 48 B, 1 49E,F, 1 5 1 C, 1 52E,F, 1 53D,E, 1 62)

Parhydraenida reichardti J. Balfour-Browne, 1975: 42. (holotype male deposited in MSP; type-locality: Itatiaia, Rio de

Janeiro, Brazil).

Diagnosis. - The pronotum is very distinctive, having the depressions deeper than in adults
of other species. Additionally, the microreticulation of the pronotum is developed to the
extreme, totaly obscuring the punctation. P. reichardti adults are unique among the known
species of this genus in the form of the lateral fossulae, each of which is divided by an elevated
region to form a deep, comparatively large depression near each pronotal angle (Fig. 15A).

Description. — Form: Ovate, moderately convex (Fig. 17C). Size: Holotype 1.74 mm long, 0.80 mm wide. Color:
Dorsum and venter black; legs, palpi and antennae dark brown. Head: Length 0.38 mm; width 0.52 mm. Frons markedly
microreticulate, punctation obscured, very sparsely pubescent; interocular foveae deep and large, width of each equal to
distance between them; interocular tuberculi prominent; basomedial foveae absent. Frontoclypeal suture evenly arcuate.
Clypeus length 0.33 width, markedly microreticulate. Labroclypeal suture slightly arcuate to rear. Labrum length 0.14
width; anterior margin arcuate in habitus view, moderately upturned. Maxillary palpomeres 2 (pseudobasal) and 4
(apical) subequal in length; palpomere 3 0.50 length of 4. Mentum trapezoidal, width at base equal length, dull, finely
microreticulate, anterior margin straight. Submentum finely microreticulate. Genae swollen, dull, finely microreticulate,
grooved laterally for reception of antennae. Postgena finely punctulate. Thorax: Pronotum length at midline 0.42 mm;
maximum width (near midlength) 0.70 mm. Anterior margin deeply bisinuate. Lateral depressions convex in middle,
markedly microreticulate, setae indistinct; sides crenulate, sinuate, markedly produced laterally. Lateral fossula distinctly
divided by convex portion of lateral depression in form of very deep, large fovea at posterior and anterior. Pronotal disc
markedly microreticulate, punctation obscured, with anterior and posterior U-shaped depression joined by extremely
shallow depression; anterior U-shaped depression with distinctive, deep fovea at each anterior extreme, these foveae
separated, from the anterior foveae of lateral depressions by ridge; posterior U-shaped depression with anterior extremes
contiguous with posterior fovea of lateral depressions. Prosternum elevated in midline; coxae contiguous. Metasternum
totally hydrofuge pubescent; middle region shallowly depressed. Elytra: Length 1.10 mm; maximum width (near
midlength) 0.80 mm. Disc moderately shiny, with six rows of large, deep punctures between suture and humeri, rows
sulcate impressed. Declivity extended through posterior 0.33. Intervals costate, width less than puncture width; each with
row of decumbent setae; first interval (from suture) ending near apical 0.25. Explanate margin moderately developed
ending near posterior 0.25. Apices slightly truncate. Abdomen: Basal four sterna with hydrofuge pubescence. Sterna 5, 6
and 7 subnitid, sparsely pubescent. Legs: Moderately short and stout. Genitalia: Male (Fig. 18A) (seven examined).

Variation. - Specimens from Santa Catarina have the pronotal depressions deeper than
specimens from Sao Paulo. Females have the labrum emarginate anteriorly and not strongly
upturned.

Natural History. - Adults have been collected in hygropetric habitats.

Distribution (Figs. 14B.162). - Presently known to be distributed in the mountains of
southeastern Brazil from the state of Espirito Santo south to the state of Santa Catarina.
Sixteen specimens have been studied in addition to the holotype (see Appendix A).

Western Hemisphere Hydraenidae 53

Figs. 18A - D, Aedeagi of Parhydraenida holotypes. (A) P. reichardti. (B) P. hygropetrica. (C) P. quadraticeps. (D) P.
lambda.

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4. Parhydraenida lambda new species
(Figs. 17G,18D,162)

Type-locality. - Jaguariaiva, 950 meters, Parana, Brazil.

Type-specimen. - The holotype male (unique) is deposited in MSP. This specimen was
collected by Reichardt and Martins, August 30, 1974.

Diagnosis. - The pronotum has the sides strongly arcuate posteriorly and fossulae and
U-shaped depressions moderately deep. The first elytral interval continues posteriorly to near
the apices. The aedeagus is highly diagnostic.

Description. — Form: Ovate, moderately convex (Fig. 17G). Size: Holotype 1.88 mm long, 0.84 mm wide. Color:
Dorsum and venter black; legs, palpi and antennae dark brown. Head: Length 0.38 mm; width 0.50 mm. Frons in middle
coarsely, closely punctate, microreticulation well developed in punctures, less apparent on interstices; very sparsely
pubescent; interocular foveae deep and large, subrugulose, width of each nearly 0.66 distance separating them; interocular
tuberculi prominent; basomedial fovea absent. Frontoclypeal suture evenly arcuate. Clypeus length slightly less than 0.50
width, punctation obscured by well developed microreticulation. Labroclypeal suture straight. Labrum length 0.33 width;
anterior margin strongly upturned, arcuate in habitus view. Maxillary palpomeres 2 (pseudobasal) and 4 (apical) subequal
in length; palpomere 3 0.50 length of 2. Mentum trapezoidal, width at base equal length, dull, finely punctulate, finely
microreticulate, anterior margin straight. Submentum finely microreticulate. Genae swollen, shiny in midregion, dull and
grooved for reception of antennae laterally. Postgena finely punctulate. Thorax: Pronotum length at midline 0.42 mm;
maximum width (near anterior 0.33) 0.68 mm. Anterior margin bisinuate in habitus view. Lateral depressions convex,
coarsely closely punctate, microreticulate within punctures, each puncture with a short but very apparent seta; sides
crenulate, sinuate, moderately produced laterally. Lateral fossulae sinuate, slightly deeper at anterior and posterior than in
midregion. Pronotal disc sculpture as lateral depressions, with anterior and posterior U-shaped depression; anterior
U-shaped depression extended to anterior margin, shape of anterior pronotal margin trisinuate when viewed from the
front; posterior U-shaped depression with “arms” terminated on disc, not connected to lateral fossulae. Posterior margin of
pronotum arcuate to posterior in midregion. Prosternum elevated in midline, not carinate; coxae contiguous. Metasternum
with longitudinal, oval depression in midline; this depression surrounded by non-pubescent area, (but I believe the
hydrofuge hairs are usually present here, being abraded in holotype). Elytra: Length 1.14 mm; maximum width (near
midlength) 0.84 mm. Disc shallowly depressed in middle, shiny, with six rows of large, deep punctures between suture and
humeri, rows deeply sulcate impressed. Origin of declivity near posterior 0.33. Intervals subcostate, width less than
puncture width, each with row of decumbent setae; first interval (from suture) extended to apices. Explanate margin well
developed, terminated near posterior 0.17. Apices rounded. Abdomen: Basal four sterna with hydrofuge pubescence (some
abraded). Sternum 5 pubescent in anterior 0.25, remainder shiny. Sterna 6 and 7 shiny, sparsely pubescent. Legs:
Moderately short and stout. Genitalia: Male (Fig. 18D) (one examined).

Natural History. - Hans Reichardt (in lift.) gives the following information concerning the
type locality: “in typical hygropetric habitat, collected together with different species of
Torridincolidae, genus Ytu ”.

Distribution. (Fig. 162). - Known only from the type locality at Jaguariaiva in the state of
Parana, Brazil.

Etymology. - The aedeagus resembles the Greek letter lambda.

5. Parhydraenida effeminata J. Balfour-Browne
(Figs. 14B,17E,162)

Parhydraenida effeminata J. Balfour-Browne, 1975:43 (holotype female deposited in MSP; type locality: Nova Petropolis,

Rio Grande do Sul, Brazil).

Diagnosis. - The pronotum is comparatively shiny, with fossulae and U-shaped depressions
extremely shallow, especially the barely perceptible posterior U-shaped depression. The first
elytral interval is extended the full length of the elytron. The body form is rather distinctive, as
a comparison between the illustrations will reveal (Fig. 17E).

Description. — Form: Ovate, moderately convex (Fig. 14B). Size: Holotype 1.84 mm long, 0.82 mm wide. Color:
Dorsum and venter black; legs, palpi and antennae light brown. Head: Length 0.38 mm; width 0.54 mm. Frons in middle
moderately coarsely, closely punctate, punctures microreticulate, interstices obsoletely so; sparsely pubescent; interocular

Western Hemisphere Hydraenidae

55

Fig. 1 9. Aedeagus of Parhydraenida bubrunipes, holotype.

foveae shallow and broad, width of each equal to intervening distance; interocular tuberculi not prominent; basomedial
fovea absent. Frontoclypeal suture evenly arcuate. Clypeus width 2.5 times length, sides convergent, sculpture as middle
of frons. Labroclypeal suture straight. Labrum length 0.33 width; anterior angles rounded; middle of anterior margin
narrowly, moderately deeply emarginate. Maxillary palpomere 4 (apical) wider than a tarsal apex, slightly longer than
palpomere 2 (pseudobasal); palpomere 3 slightly less than 0.50 length of 4. Mentum trapezoidal, width at base equal
length, microreticulate, dull, anterior margin straight. Submentum evenly, finely punctulate. Genae swollen, dull, finely
punctulate, grooved laterally for reception of antennae. Postgena finely punctulate. Thorax: Pronotum length at midline
0.40; maximum width (near anterior 0.33) 0.66 mm. Anterior margin bisinuate. Lateral depressions deflexed slightly at
anterior angles, not convex, moderately coarsely, very closely punctate, each puncture with short but very apparent seta;

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Perkins

strongly microreticulate in punctures, interstices shiny, very obsoletely microreticulate; sides crenulate, sinuate, not
markedly produced laterally. Lateral fossulae sinuate, shallow for entire length. Pronotal disc sculptured as lateral
depressions, with very shallow anterior and posterior U-shaped depression, latter nearly imperceptible; anterior
U-shaped depression deepest and well marked at anterior margin. Posterior margin very slightly arcuate to rear in
midregion. Prosternum slightly elevated in midline, not carinate; coxae contiguous. Metasternum entirely hydrofuge
pubescent, depressed in midregion. Elytra: Length 1.16 mm; maximum width (near midlength) 0.82 mm. Disc shiny,
with six rows of large, deep punctures between suture and humeri, rows very shallowly sulcate impressed. Declivity
beginning near posterior 0.33. Intervals subcostate, width less than puncture width; each with row of decumbent setae;
first interval (from suture) extended to apices. Explanate margin moderately developed. Apices very slightly dehiscent
at suture. Abdomen: Basal four sterna with hydrofuge pubescence. Sternum 5 hydrofuge pubescent in anterior 0.25,
remainder shiny. Sternum 6 shiny, posterior margin strongly arcuate to front, sparsely pubescent. Sternum 7 ovate,
shiny, sparsely pubescent. Legs: Moderately short and stout. Genitalia: Male unknown.

Distribution. (Figs. 14B, 162). - Presently known from the states of Rio Grande do Sul and
Santa Catarina, Brazil. Refer to J. Balfour-Browne (1975) for locality data.

6. Parky dr aenida paralonga new species
(Figs. 17D, 20A,162)

Type-locality. - Campos do Jordao, 1650 meters, Sao Paulo, Brazil.

Type-specimens. - The holotype male and allotype with identical data are deposited in
MSP. Paratypes from the same locality, all females, are deposited in MSP (15), USNM (2)
and PDP (2). These specimens were collected by Hans and Bartyra Reichardt, January, 1976.

Diagnosis. - Adults are quite similar externally to those of P. hygropetrica in that both
groups have the first elytral interval ending at the posterior 0.25. Additionally, pronota of both
groups have dull reliefs and rather shallow depressions. P. paralonga adults differ in larger size
(ca. 1.75 vs. 1.55 mm long), body form (Figs. 17D,F), more deeply sulcate impressed elytra and
aedeagal form (Figs. 18B,20A).

Description. — Form: Ovate, moderately convex (Fig. 17D). Size: Holotype 1.72 mm long, 0.76 mm wide. Color
Dorsum and venter black; legs, palpi and antennae dark brown. Head: Length 0.34 mm; width 0.48 mm. Frons in middle
coarsely punctate, markedly microreticulate, very sparsely pubescent; interocular foveae deep, subrugulose, width of each
nearly 0.50 distance separating them; interocular tuberculi prominent; basomedial fovea absent. Frontoclypeal suture
evenly arcuate. Clypeus length 0.50 width, markedly microreticulate, sides convergent. Labroclypeal suture straight.
Labrum length 0.33 width; anterior margin moderately upturned, arcuate in habitus view. Maxillary palpomere 2
(pseudobasal) and 4 (apical) subequal in length: palpomere 4 swollen; palpomere 3 0.50 length of 2. Mentum trapezoidal,
dull, finely microreticulate; anterior margin straight. Submentum evenly, finely punctulate, punctures contiguous. Genae
swollen, dull, finely punctulate, grooved laterally for reception of antennae. Postgena finely punctulate. Thorax: Pronotum
length at midline 0.40 mm; maximum width (near anterior 0.33) 0.64 mm. Anterior margin bisinuate. Lateral depressions
slightly convex, coarsely punctate, markedly microreticulate; sides slightly crenulate, sinuate not markedly produced
laterally. Lateral fossulae slightly sinuate, posterior 0.50 slightly deeper than remainder. Pronotal disc sculptured as
lateral depressions, with posterior and anterior U-shaped depression; anterior U-shaped depression wider than posterior,
extended to anterior margin, deepest near margin; posterior U-shaped depression with “arms” terminated on disc not
extended to lateral fossulae. Posterior margin arcuate to rear in midregion. Prosternum elevated in midline, not carinate;
coxae contiguous. Metasternum entirely pubescent, depressed in midregion. Elytra: Length 1.08 mm; maximum width
(near midlength) 0.76 mm. Disc moderately dull, with six rows of large deep punctures between suture and humeri, rows
deeply sulcate impressed. Declivity not well defined. Intervals subcostate, width less than puncture width; first interval
(from suture) ended near apical 0.25. Explanate margin moderately developed, ending near apical 0.20. Apices slightly
truncate. Abdomen: Basal four sterna with hydrofuge pubescence. Sternum 5 hydrofuge pubescence in anterior 0.25,
remainder shiny. Sterna 6 and 7 shiny, sparsely pubescent. Legs: All legs moderately short and stout. Genitalia: Male
(Fig. 20A) (one examined).

Variation. - Females have the labrum emarginate and not strongly upturned.

Distribution. - (Fig. 162) Known only from the type-locality at Campos do Jordao in the
state of Sao Paulo, Brazil.

Etymology. - Latin, para (beside) plus longa (long). This name refers to the single long
paramere of the aedeagus.

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57

7. Parhydraenida alida J. Balfour-Browne
(Figs. 12B,20B,162)

Parhydraenida alida J. Balfour-Browne, 1975: 40. (holotype male deposited in MSP; type-locality: Barra da Tejuca, Rio

de Janeiro, Guanabara, Brazil).

Diagnosis. - Combination of small size (about 1.46 mm long), shiny, non-microreticulate
pronotal reliefs, first elytral interval terminated near the posterior 0.25, and aedeagal form
serve as diagnostic characteristics. Similarities in aedeagal structure (Figs. 18B, 20B) and body
size and form (Figs. 12B,17F) indicate that P. alida and P. hygropetrica form a sister-species
pair. Adults of the two species are differentiated externally by the pronotal reliefs, which are
non-microreticulate and shiny in P. alida specimens; dull and microreticulate in P.
hygropetrica specimens.

Description. — Form: Ovate, moderately convex (Fig. 12B). Size: Holotype 1.46 mm long, 0.64 mm wide. Color
Dorsum and venter black; legs, palpi and antennae brown. Head: Length 0.30 mm; width 0.42 mm. Frons in middle
moderately coarsely punctate, microreticulate in punctures, interstices obsoletely so, moderately shiny; very sparsely
pubescent; interocular foveae strongly microreticulate, deep and large, width of each nearly 0.66 distance separating them;
interocular tuberculi prominent; basomedial fovea absent. Frontoclypeal suture evenly arcuate. Clypeus length 0.33 basal
width, sides convergent, microreticulate, punctures somewhat obscured. Labroclypeal suture straight. Labrum length 0.25
width; anterior border shallowly emarginate, strongly upturned. Maxillary palpomere 2 (pseudobasal) and 4 (apical)
subequal in length; palpomere 3 0.50 length of 2. Mentum trapezoidal, width at base equal length, finely microreticulate,
anterior margin straight. Submentum finely microreticulate. Genae swollen, dull, finely microreticulate, grooved laterally
for reception of antennae. Postgena finely punctulate. Thorax: Pronotum length at midline 0.36 mm; maximum width
(near anterior 0.33) 0.54 mm. Anterior margin slightly bisinuate. Lateral depressions with edges rounded but remainder
not convex, with short but very apparent setae; sides crenulate, sinuate, not markedly produced laterally. Lateral fossulae
much broader in anterior than posterior, shining, finely microreticulate, setae much less apparent than those of lateral
depressions. Pronotal disc with well developed anterior and posterior U-shaped depressions, anterior broadest and extended
to anterior margin; posterior U-shaped depression ended on disc, not connected to lateral fossulae. Posterior margin
arcuate to rear in midregion. Prosternum elevated in midline, not carinate; coxae contiguous. Metasternum entirely
hydrofuge pubescent, median region depressed. Elytra: Length 0.88 mm; maximum width (near midlength) 0.64 mm. Disc
moderately shiny, with six rows of moderately large, deep punctures between suture and humeri, rows sulcate impressed.
Origin of declivity near posterior 0.33. Intervals subcostate, width slightly less than puncture width; each with row of
decumbent setae; first interval (from suture) terminated at apical 0.25. Explanate margin moderately developed. Apices
slightly truncate. Abdomen: Basal four sterna plus anterior 0.33 of sternum 5 hydrofuge pubescent. Posterior 0.66 of
sterna 5 and 6 subnitid, sparsely pubescent. Legs: Relatively stout. Genitalia: Male (Fig. 20B) (one examined).

Variation. - The labrum is more deeply emarginate in females, the edge of the emargination
being upturned slightly. Maxillary palpomere 4 is larger in males, the lateral surface more
arcuate, the medial sinuate; in females the medial is slightly arcuate.

Distribution. - (Fig. 162) Presently known only from the state of Rio de Janeiro, Brazil.

8. Parahydraenida hygropetrica new species
(Figs. 17F,18B,162)

Type-locality. - Santa Teresa, Espirito Santo, Brazil.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in MSP. These specimens and four paratypes from the same locality (two MSP; one USNM;
one PDP) were collected by S. Vanin and O. Flint, April 23, 1977.

Diagnosis. - Small size (about 1.55 mm long), dull, microreticulate pronotal reliefs, first
elytral interval ending near posterior 0.25, and aedeagal form (Fig. 18B) serve as diagnostic
characteristics. The pronotal microreticulation is similar to that of P. paralonga adults; refer to
the diagnosis of that species for further comments. Body form and size plus aedeagal structure
indicate that P. hygropetrica and P. alida are sister-species. The pronotal reliefs of P. alida
adults, however, are shiny, non-microreticulate.

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Figs. 20A - B, Aedeagi of Parhydraenida holotypes. (A) P. paralonga. (B) P. alida.

Western Hemisphere Hydraenidae

59

Description. — Form: Ovate, moderately convex (Fig. 17F). Size: Flolotype 1.52 mm long, 0.68 mm wide. Color:
Dorsum and venter black; legs, palpi and antennae dark brown. Head: Length 0.30 mm; width 0.44 mm. Frons
microreticulate, moderately coarsely punctate, punctures obscured by microreticulation, very sparsely pubescent;
interocular foveae deep and large, width of each nearly 0.66 distance separating them; interocular tuberculi prominent;
basomedial fovea absent. Frontoclypeal suture evenly arcuate. Clypeus length 0.33 width, microreticulate, sides
convergent. Labroclypeal suture straight. Labrum length 0.25 width; anterior margin upturned, arcuate in habitus view.
Maxillary palpomere 4 slightly swollen, slightly longer than palpomere 2; palpomere 3 shorter than 2. Mentum
trapezoidal, width at base equal length, shining, very finely microreticulate, anterior margin straight. Submentum shiny,
finely punctulate. Genae swollen, very shiny in midregion, dull and microreticulate laterally; grooved laterally for
reception of antennae. Thorax: Pronotum length at midline 0.36 mm; maximum width (near anterior 0.33) 0.56 mm.
Anterior margin very shallowly bisinuate. Lateral depressions very slightly convex, microreticulate, coarsely closely
punctate; sides crenulate, sinuate, moderately produced laterally. Lateral fossulae slightly sinuate, of equal depth along
entire length. Pronotal disc microreticulate, moderately coarsely, closely punctate, with anterior and posterior U-shaped
depression; anterior U-shaped depression extended to anterior margin; posterior U-shaped depression with “arms” ended
on disc, not connected to lateral fossulae. Posterior margin of pronotum arcuate posteriorly in midregion. Prosternum
elevated in midregion; coxae contiguous. Metasternum entirely hydrofuge pubescent; midline with narrow groove. Elytra:
Length 0.88 mm; maximum width (near midlength) 0.68 mm. Disc moderately flat, shiny, with six rows of large, deep
punctures between suture and humeri, rows shallowly sulcate impressed. Declivity origin near posterior 0.33. Intervals
subcostate, width less than puncture width; each with row of decumbent setae; first interval(from suture) ended at apical
0.25. Explanate margin moderately developed, ended near posterior 0.17. Apices rather broad, arcuate. Abdomen: Basal
four sterna with hydrofuge pubescence. Sternum 5 pubescent in anterior 0.25, remainder shiny. Sterna 6 and 7 shiny,
moderately produced posteriorly. Legs: Moderately short and stout. Genitalia: Male (Fig. 18B) (five examined).

Variation. - The labrum is emarginate and not markedly upturned in females. Other sexual
dimorphism includes size and shape of maxillary palpomere 4. In males this article is longer
and wider than in females; the width being greater than the apical width of the last tarsomere
in males, less than this width in females.

Natural History. - The type-series were collected from a hygropetric habitat.

Distribution. - (Fig. 162). Known only from the type-locality at Santa Teresa in the State of
Espirito Santo, Brazil.

Etymology. - Latin, hygro (wet) plus petrus (rock).

9. Parhydraenida pentatenkta new species
(Figs. 17B,50A,162)

Type-locality. - 38 km E. of Portoviejo, Manabi Province, Ecuador.

Type-specimen. - The holotype female (unique) is deposited in USNM. This specimen was
collected by P. Spangler, A. Langley and J. Cohen, May 11, 1975.

Diagnosis. - Adults of this species are unique in reduction of hydrofuge pubescence of the
abdomen to the first two sterna plus the anterior 0.33 of sterna 3. The remaining sterna are
shiny and with very sparse, non-hydrofuge hairs. Adults of all other currently known species in
the genus Parhydraenida have the first four sterna plus the anterior portion of sternum 5
hydrofuge pubescent. P. pentatenkta adults are also quite distinctive dorsally, as the pronotum
is comparatively large and quite transverse (Fig. 17B). The deflexed anterior clypeal angles and
labrum are worthy of note.

Description. — Form: Ovate, moderately convex (Fig. 17B). Size: Holotype 1.56 mm long, 0.80 mm wide. Color:
Brown. Head: Length 0.30 mm; width 0.54 mm. Frons rugulose, strongly microreticulate, very sparsely pubescent;
interocular foveae deep and large, width of each nearly equal distance separating them; interocular tuberculi prominent;
basomedial fovea very slightly apparent. Frontoclypeal suture evenly arcuate. Clypeus length 0.33 width, finely rugulose,
moderately pubescent, anterior angles deflexed. Labroclypeal suture straight in habitus view; viewed anteriorly it is
arcuate due to deflexed anterior angles of clypeus. Labrum length 0.33 width; very markedly deflexed, nearly at right
angle to major plane of clypeus; anterior margin emarginate and prominently pubescent. Maxillary palpus very short;
palpomeres 2 and 4 subequal in length, palpomere 3 0.50 length of 2. Mentum markedly punctulate, pubescent.
Submentum punctulate. Genae swollen, dull, punctulate, grooved laterally for reception of antennae. Postgena punctulate.
Thorax: Pronotum length at midline 0.42 mm; maximum width (near anterior 0.33) 0.76 mm. Anterior margin bisinuate,

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anterior angles produced. Lateral depressions broad, very slightly convex, rugulose; sides crenulate, very slightly sinuate
at posterior, moderately produced laterally. Lateral fossulae slightly deeper at anterior and posterior than in midregion.
Pronotal disc rugulose, with anterior and posterior U-shaped depression connected by narrow median groove. Posterior
margin arcuate to rear in midregion. Prosternum slightly elevated in midregion. Metasternum hydrofuge pubescent;
longitudinally depressed in middle. Elytra: Length 1.04 mm; maximum width (near midlength) 0.80 mm. Disc dull,
with six rows of large, deep punctures between suture and humeri, rows deeply sulcate impressed. Declivity origin near
posterior 0.33. Intervals costate, width less than puncture width; each with row of decumbent setae; first interval (from
suture) ended near posterior 0.20. Explanate margin moderately developed, markedly serrate in anterior 0.20. Apices
slightly truncate. Abdomen: Basal two sterna plus anterior 0.33 of sternum 3 hydrofuge pubescence, remainder shiny,
very sparsely pubescent. Legs: Short and stout. Genitalia: Male unknown.

Natural History. - The following label description accompanies the holotype: “collected in splash zone at
waterfall”.

Distribution. - (Fig. 50A) Known only from the type-locality near Portoviejo in western
Ecuador.

Etymology. - Greek, penta (five) plus tenkta (wettable). This name refers to the five
abdominal sterna which lack hydrofuge pubescence and are, therefore, wettable.

GENUS HYDRAENA KUGELANN

Hydraena Kugelann 1794:579 (type-species: Hydraena riparia Kugelann 1794:579). - d’Orchymont, 1916:96. -

d’Orchymont, 1923:33. - Knisch, 1924:33. - F. Balfour-Browne, 1958:178. - Janssens, 1965).

Discussion. - Hydraena is markedly diverse, the total number of species described for the

world being about 400, of which 95 are now known for the Western Hemisphere. It is the most
diverse genus in the family, Ochthebius being second, with about 300 species. Judging from the
number of new species described in this paper and those by Janssens (1965, 1972) and Zwick
(1977), one must suppose that the actual number of Hydraena species is considerably greater
than the present figure.

Members of Hydraena are on all continents, but are notably absent from New Zealand
(d’Orchymont, 1936a), where they are apparently replaced by members of Orchymontia Broun
1919 (d’Orchymont 1936a; Zwick, 1975). In the Western Hemisphere, Hydraena members are
in most areas, being absent from Alaska, the Great Plains region of the United States, Chile,
Uruguay, and all of Argentina except extreme northernmost (Fig. 160).

Current data indicate that the greatest concentration of species is in California and
Mexico-Central America, but more field work remains to be done, especially in South America.
Distributional considerations are discussed in more detail in the section on zoogeography.

During the 1800’s, students of the genus organized the species into a number of subgenera,
based in large part upon rather insignificant and unstable characteristics. Consequently, most
of these subgenera have been found to be of species-group rank when studied rigorously.

Rey (1884) was the first worker to use the number of elytral striae between the suture and
humeral callus as a means of subgeneric separation. Species with more than six striae (usually
10) he placed in Hydraena (sensu stricto ), whereas those with six were placed into his
subgenera Haenydra or Hadrenya , depending upon shape of metasternal plaques.

Kuwert (1888) erected the subgenera Taenhydraena, Phothydraena, Hoplydraena,
Holcohydraena, Sphaenhydraena and Grammhydraena. These names were either new for
groups already proposed by Rey (F. Balfour-Browne, 1958), or the groups were based upon
insignificant features.

D’Orchymont (1930) was the first to discover that aedeagi of males of species with six
elytral striae lacked parameres, whereas males of species with more than six striae had

Western Hemisphere Hydraenidae

61

parameres. On this basis he accepted Rey’s (1884) Hydraena (sensu stricto ) (with parameres)
and Haenydra (lacking parameres). He also recognized Kuwert’s (1888) subgenus
Phothydraena , which was erected for the single species H. testacea because of the unusually
large punctures at the margin of the elytron in adults. This appears to be inconsistent, as the
aedeagus and elytral striae of H. testacea clearly place it in Hydraena (sensu stricto).

In a paper on the phylogeny of Hydraena , d’Orchymont (1936a) tabulated those characters
which he deemed significant, and recognized the subgenera Hydraena ( sensu stricto ),
Holcohydraena, Taenhydraena, Phothydraena and Haenydra.

Kuwert (1888) erected Holcohydraena for Hydraena rugosa Mulsant 1884, of Europe and
the Iberian Peninsula, because of lack of metasternal plaques. Adults of some species of New
World Hydraena also lack plaques, but these species are related to others from this
geographical area whose adults have plaques. Plaque loss occurs in species which are of
different lineages and is obviously not of subgeneric significance. Zwick (1977) has found the
same to be true for Australian Hydraena.

Kuwert’s (1888) Taenhydraena, which contains only Hydraena exarata Kiesenwetter 1865
of the Iberian Peninsula, was established because of the elevated alternate elytral intervals of
adults of that species. Adults of Hydraena alternata from Mexico also have this trait, but this
species is probably of a different lineage, the similarities of the two being convergent. Aedeagi
of H. exarata males (d’Orchymont, 1936b) do not indicate any obvious relationship to H.
alternata. Further study is needed here, but I suspect that the characteristics upon which
Taenhydraena is based will eventually be considered of only species-group significance.

More recently, Janssens (1972), in a paper describing one new species from Vietnam, two
from Ghana, and one from Paraguay, has proposed a new genus, which he names
Hydraenopsis. The principal basis for this proposed taxon is form of the aedeagus, more
specifically, location of the insertion of the parameres. He states, “Parmi ces caracteres, l’un
m’a paru suffisant pour creer une coupe generique groupant la majorite des especes
intertropicales connues et prenant le nom d’ Hydraenopsis n. g. II s’agit de la structure des
genitalia: au lieu d’etre attaches a la base, les parameres du nouveau genre, plus courtes que
chez Hydraena (sensu stricto), sont attaches au centre du corps basal, ainsi qu’on le verra dans
les figures 2, 4 et 5.”

Emphasizing form of the aedeagus further, he states, “....le caractere determinant pour
conclure a la validite du nouveau genre Hydraenopsis reside dans la structure tres particulere
des genitalia et notamment dan la mode d’insertion de parameres.”

I have found during this study that insertion of the parameres varies greatly from species to
species in the Neotropical fauna, and virtually all intermediate types are seen between those
whose males have parameres inserted at the base and those whose males have parameres near
the apex. For instance, one could cite the following species as examples in a sequence of from
base to apex insertion: chiapa - scintillabella - alternata - maureenae - orcula - colymba -
youngi - paeminosa.

Further, males of several species have one paramere closer to the base than the other, some
examples being trinidensis, turrialba, spangleri and browni. Clearly, this great variation of
paramere insertion precludes using this character for generic separation.

The following external characteristics were cited by Janssens (1972) as significant, “....la
form du pronotum et l’article apical des palpes maxillaires toujours depourvu de noircessement
a l’apex sont des caracteres dont la Constance corrobore la stabilite du nouveau genre qu’on
reconnaitra ainsi assez commodement a premiere vue.” These characteristics are also highly

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variable within neotropical Hydraena, even within the aggregate of species herein presented as
the leechi Group.

Consequently, I do not recognize Hydraenopsis Janssens as a valid genus, and consider all of
the Hydraena in the Western Hemisphere as members of Hydraena (sensu stricto). However,
relative ranking of primarily temperate vs. primarily tropical components of Hydraena would
require additional thought if and when constant differentiating characteristics were elucidated.

Relative to amount of published data regarding Palearctic Hydraena , available information
on New World forms is scant indeed. This is due in large part to the lack of material available
to earlier workers such as d’Orchymont who, in 1923, had only about 100 specimens
representing the nine species known at that time. Through the efforts of recent American
students of aquatic Coleoptera, most notably Hugh B. Leech and Paul J. Spangler, specimens
have gradually accumulated in collections; as a result of these efforts, more than 10,000
specimens were available for this study.

Publications concerning Western Hemisphere Hydraena began with Kiesenwetter’s
description of H. pennsylvanica and H. marginicollis in 1849. Subsequent to that work, 16 taxa
have been described in the following sequence: H. punctata LeConte 1855; H. longicollis, H.
puncticollis , H. sordida Sharp, all 1882; H. angulicollis Notman 1921; H. grouvellei, H.
sahlbergi, H. germaini, H. vandykei, H. guadelupensis, all d’Orchymont 1923; Hydraena
needhami d’Orchymont 1929; H. plaumanni d’Orchymont 1937; H. insularis d’Orchymont
1945; Hydraena vandykei niger Hatch 1965; H. paraguayensis Janssens 1972.

Despite relatively few descriptions, attempts to obtain types did not meet with complete
success. Although a number of European museums were contacted, Kiesenwetter’s types of H.
pennsylvanica and H. marginicollis were not found. D’Orchymont (1945), despite his extensive
knowledge of the genus, was apparently unable to find the type of H. marginicollis as he based
his concept of the species upon a specimen in the Institut royal des Sciences Naturelles de
Belgique collection labelled “cotype?” of H. marginicollis. The above suggests that the types of
H. marginicollis have been destroyed or irrevocably lost. However, combination of small size
and type locality (“Westindien” and New Orleans) leave little doubt as to the identify of H.
marginicollis. To firmly establish the identity of H. marginicollis a neotype is designated
herein. Likewise, I believe that the single type-specimen of H. pennsylvanica has reached a
similar fate; therefore a neotype is designated to insure stability.

Efforts to obtain holotypes of d’Orchymont’s H. insularis , H. grouvellei and H. germaini
also failed. However, paratypes of each of thse species have been studied and there is no
confusion concerning their identities. I believe that futher search at European museums (where
I have already enquired) will result in location of these holotypes, therefore no lectotypes are
designated for these species.

The type series of Sharp’s Neotropical species H. longicollis , H. puncticollis , and H.
sordida have been studied and lectotypes are designated for each.

Holotypes of the following species have been seen: H. sahlbergi d’Orchymont; ; H.
plaumanni d’Orchymont; H. guadelupensis d’Orchymont; ; H. punctata LeConte; H.
angulicollis Notman; H. needhami d’Orchymont; H. vandykei d’Orchymont; H. vandykei
niger Hatch.

The holotype and two paratypes of H. paraguayensis Janssens were requested from the
Institut royal des Sciences Naturelles de Belgique (through E. Janssens). However, when the
material was received, it was found to contain the pin with holotype label and locality label, but
the specimen was no longer glued to the card. A search of the box proved fruitless. Therefore, a

Western Hemisphere Hydraenidae

63

lectotype is herein designated.

Of the 18 previously described species, only one instance of new synonomy was encountered.
H. needhami d’Orchymont 1929 was found to be conspecific with H. punctata 1855.

Pronotal features. - The major relief features of Hydraena pronota (Fig. 2 1C) consist of
anteroexternal foveolae (AEF), margins (M), posteroexternal foveolae (PEF) and
posterointernal fovelae (PIF). In adults of certain species, such as H. circulata (Fig. 21C), the
antero- and posteroexternal foveolae are markedly confluent and form a longitudinal depression
similar to the “lateral fossulae” of Ochthebius (Fig. 98A). In adults of other species, such as H.
bituberculata (Fig. 3 1C) and H. cuspidicollis (Fig. 48C), the antero- and posteroexternal
foveolae are distinct, although joined by a shallow depression. In adults of species of the
marginicollis Group, most pronotal depressions are obsolete, only the anteroexternal foveolae
being apparent (e.g. marginicollis , (Fig. 54C)).

Diagnosis. - Elongate maxillary palpi (Fig. 148C) readily distinguish Hydraena adults from
those of all other Western Hemisphere Hydraenidae except Spanglerina. From Spanglerina
adults, Hydraena adults are distinguished by 1) the less markedly angulate pronotum
(cf. Figs. 21C,54C,65E), which lacks a median ridge or anterointernal foveolae, 2) absence of
foveae near the anterior margin of the labrum (cf. Figs. 54D,65F), 3) procoxae not as widely
separated as mesocoxae (cf. Figs. 21D,E,65D), 4) without metacoxae widely separated
(cf. Figs. 21D,65C), and 5) males with aedeagus of a different basic plan
(cf. Figs. 22A,45A,67A-D).

Description. — Form: Generally elongate and relatively depressed, adults of a few species elongate-oval. Size:
Length about 1.00-2.00 mm, width about 0.47-0.85 mm. Females generally larger than males. Color: Adults of some
species black, some brown, a few with testaceous or ochraceous legs contrasted with darker body color, many with black
pronotal fascia or macula bordered by testaceous area. Head: Very finely, sparsely punctate to coarsely punctate, adults of
many species with well developed microreticulation. Interocular fovea and interocular tuberculi (ocelli) absent. Clypeus
transverse, sides convergent anteriorly. Labrum bilobed, without apparent sexual dimorphism. Maxillary palpus elongate,
palpomere 2 generally as long as 3 and 4 combined. Mentum generally very slightly longer than wide, finely
microreticulate or punctulate. Genae smooth or with a posterior ridge. Antennae of nine articles (4 + 5). Thorax:
Pronotum with sides slightly to moderately produced at middle, denticulate; anterior angles produced in one species only.
Lateral areas of pronotum with more or less developed anteroexternal foveolae, posteroexternal foveolae in many adults
also. Disc with posterointernal foveolae present or absent; anterior region of many adults with shallow transverse
depression. Sculpture of disc varied from extremely finely sparsely punctate to coarsely punctate and with microreticulate
interstices. Prosternum of most adults with coxae separated by thin carina, of few adults separated from carina by thin
shelf. Mesosternum of most adults with internal and external carinae divergent from anterior to posterior; intercoxal
process of most adults quite narrow, few adults as wide as long; apex varied from blunt to acute, of few adults elevated to
form ridge contiguous with same on metasternum. Metasternum with glabrous plaques present or absent; plaques of
various shapes including elongate, oval, totally carinate, carinate at lateral extremes and arcute. Elytra: Most adults with
10 rows of punctures between suture and humeral callus, few adults with punctures random on disc or on entire elytron.
Intervals varied from flat to subcarinate, in few adults with alternate intervals elevated. Explanate margin very narrow to
broad. Elytral apices, in posterior aspect, in most adults turned upward in form of angle with one another; in few adults,
angles not formed. Abdomen: Intercoxal segment flat or concave. First four sterna and anterior region of 5 with hydrofuge
pubescence. Posterior region of sterna 5 very sparsely pubescent in males, with relatively long setae in females. Sternum 6
sparsely pubescent. Apical sternum (actual tenth) retracted in some adults. Legs: Protarsi without obvious expanded pads
of suction setae. Protibiae of many adults enlarged or excavate near apex. Mesotarsi with symmetrical claws except for
adults of one species. Mesotibiae straight in most, arcuate in few adults. Metatibiae varied from slender to markedly
enlarged, adults of some species with brush of hairs, prominent spines, or tubercles. Genitalia: Aedeagus varied markedly,
paramere insertion varied from at base to near apex. Paramere shape varied from slender to lobate, males of few species
with one paramere bifid. Right paramere of most males larger than left, but not in form of cup into which remainder of
aedeagus rests. Central portion of aedeagus varied from slender to nearly oval. Apex of few males with flagellum.

Quaest. Ent., 1980, 16 (1,2)

64

Perkins

Key to the groups of Western Hemisphere Hydraena

1 (0) Posterior ridge of genae well developed (Fig. 21H); intercoxal segment of

abdomen concave, with posterior margin markedly arcuate (Fig. 2 ID); scintilla

absent 2

T Posterior ridge of genae absent (Figs. 48E,54D,57A,63G) or nearly
imperceptible; intercoxal segment flat, with posterior margin straight or weakly

arcuate (Figs. 48D,57B,63A,B); scintilla present or absent 3

2 ( 1 ) Pronotum widest near midlength (Fig. 2 1C); elytral punctures serial or, in few
adults, with few random punctures on disc (Figs. 21A,G); prosternal carina not
produced anteriorly into a short spine, or very weakly so (Fig. 2 IE); species

from Canada and the United States circulata Group, p. 72

2' Pronotum widest before midlength; elytral punctures entirely random on disc;
prosternal carina produced anteriorly into a short spine; one species from

Surinam paeminosa Group, p. 210

3 ( 1') Pronotum with posterointernal foveolae; scintilla present or absent

(Figs. 31C,32B,48C) leechi Group, p. 102

y Pronotum without posterointernal foveolae (Figs. 54A,C); scintilla absent ....

marginicollis Group, p. 164

Key to circulata Group species of Western Hemisphere Hydraena

1 ( 0 ) Meso- and metatibiae arcuate H. quadricurvipes, new species p.

V Meso- and metatibae not arcuate

2 ( 1 ) Elytral disc with some random punctures

2' ( 1 ) Elytral disc with punctures in series

3 (2) Plaques arcuate, separated by twice plaque width; Appalachian Mountains . . .

H. appalachicola , new species, p.

y Plaques straight, separated by plaque width; Lake County, California

H. mignymixys, new species, p.

4 ( 2') Species from eastern United States and adjacent Canada (including angulicollis

Notman, see distribution map, (Fig. 25A)

4' Species from western United States and adjacent Canada

5 ( 4 ) Pronotum with dark brown macula on disc, not extended into lateral depressed

areas; aedeagus as illustrated (Fig. 26B) H. atlantica, new species, p.

5' Pronotum dark brown except for narrow brownish or testaceous border;
aedeagus otherwise

6 ( 5') Elytral intervals not elevated; plaques separated anteriorly by more than plaque

width; pronotal punctation more widely separated; average size smaller;

aedeagus as illustrated (Fig. 24D) H. angulicollis Notman, p.

6' Elytral intervals slightly elevated; plaques separated anteriorly by plaque width;
pronotal punctation more closely spaced; average size larger; aedeagus
otherwise

7 ( 60 Plaques separated posteriorly by plaque width; aedeagus as illustrated

(Fig. 29B) H. ancylis, new species, p.

1' Plaques separated posteriorly by less than plaque width; aedeagus as illustrated
(Fig. 29A) H. pennsylvanica Kiesenwetter, p.

93

2

3

4

83

92

5
8

85

6

82

7

99

96

Western Hemisphere Hydraenidae

65

8 ( 40 Plaques elevated, carinate at posterior in most specimens, separated at posterior

by about four times plaque width or more; black; aedeagus as illustrated

(Fig. 29D) H. nigra Hatch, p.

8' Plaques not elevated, separated by twice plaque width, or less;

black or brownish

9 ( 8') Body form broad, 1.78 mm x 0.88 mm; legs short, stout; palpi relatively short;

aedeagus as illustrated (Fig. 28 A); Yosemite Falls, California

H. yosemitensis, new species, p.

9' Characters not as above

10 (90 Metasternum with distinctive long and dense pubescence lateral to each plaque;

pronotum smaller, more incised at rear; Pacific coast states

10' Metasternum without unusual long and dense pubescence lateral to plaques,
pronotum larger, less incised at rear

11 (10 ) Aedeagus as illustrated (Fig. 29C) H. vandykei d’Orchymont, p.

1 1' Aedeagus as illustrated (Figs. 30A,B) H. sierra , new species, p.

12 (100 Legs and lateral borders of pronotum ochraceus; aedeagus as illustrated

(Fig. 28C) H. californica, new species , p.

12' Legs and lateral borders of pronotum brown or black

13 (120 Aedeagus with setae of parameres short, sparse

13' Aedeagus with setae of parameres long, dense

14 (13 ) Aedeagus as illustrated (Figs. 26A,C,D) H. pacifica , new species, p.

14' Aedeagus as illustrated (Fig. 28D) H. petila, new species, p.

15 (130 Aedeagus with parameres broad in lateral view

15' Aedeagus with parameres slender in lateral view

16 (15 ) Aedeagus as illustrated (Fig. 22A) H. tuolumne, new species, p.

16' Aedeagus as illustrated (Fig. 22B) H. occidentalism new species, p.

17 (150 Aedeagus as illustrated (Fig. 22C) H. arenicola, new species p.

17' Aedeagus as illustrated (Fig. 22D) H. circulata, new species, p.

Key to leechi Group species of Western Hemisphere Hydraena

1 ( 0 ) Pronotal scintilla present (Figs. 31C,32B,40D)

V Pronotal scintilla absent

2 ( 1 ) Male metatibial brush present (Figs. 32D-G)

2' Male metatibial brush absent; female specimens

3 ( 2 ) Plaques oval or absent

3' Plaques carinate

4 (3) Tubercle lateral to each plaque (Figs. 31H,35B); aedeagus as illustrated

(Fig. 33D); southern Arizona H. bituberculata , new species, p.

4' Tubercle absent

5 ( 40 Size larger, about 1.92 - 2.02 mm long; protibia excavate near apex; profemoral

prominence cariniform; aedeagus as illustrated (Figs. 36B,D); Oaxaca and

Hidalgo, Mexico H. scintilla , new species, p.

5" Size smaller, about 1.85 mm long or less; protibia not excavate near apex;
profemoral prominence tuberculate

6 ( 50 Size larger, about 1.80 x 0.76 mm; aedeagus as illustrated (Fig. 33A); Arizona,

84

9

94

10

11

12

100

101

88

13

14

15

86

91

16

17

79

78

75

74

2

30

3

9

4

7

109

5

111

6

Quaest. Ent., 1980, 16 (1,2)

66

Perkins

New Mexico, Texas, northern Mexico H. leechi, new species, p. 103

6' Size smaller, about 1.76 x 0.76 mm; aedeagus as illustrated (Fig. 36A); Jalisco,

Mexico H. scopula, new species, p. 115

7 ( 3') Plaques truncate posteriorly; aedeagus as illustrated (Fig. 36C); Zacatecas,

Mexico H. canticacollis, new species, p. 113

7/ Plaques not truncate posteriorly 8

8 ( 7 ) Plaques arcuate; protibia parallel sided; aedeagus as illustrated (Fig. 33B);

Durango, Mexico H. breedlovei, new species, p. 106

8' Plaques straight; protibia expanded; aedeagus as illustrated (Fig. 33C);

southern Arizona H. arizonica , new species, p. 108

9 ( 2 ') Tubercle lateral to each plaque; southern Arizona; females of

H. bituberculata, new species, p. 109

9' Tubercle absent 10

10 (9') Elytral punctures on disc random 11

10' Elytral punctures on disc in series 12

11 (10 ) Form narrow, length about 2.92 times width; longer, about 1.46 mm; aedeagus

as illustrated (Fig. 4 1C); Appalachian Mountains of Virginia

H. maureenae, new species, p. 138

11' Form wider, length about 2.02 - 2.30 times width; shorter, about 1.38 mm;

aedeagus as illustrated (Figs. 41A,B); Ozark Plateau of Missouri, Oklahoma,
Tennessee, Indiana H. ozarlcensis, new species, p. 136

12 (10') Procoxae separated from median carina by narrow shelf; Paraguay

H. paraguay ensis Janssens, p. 128

12' Procoxae not separated from median carina by narrow shelf 13

13 (12') Elytron with alternate intervals elevated; aedeagus as illustrated (Fig. 37 A);

Durango, Mexico H. alternata, new species, p. 116

13' Elytron with alternate intervals not elevated 14

14 (13') Elytral margin, viewed posteriorly, not elevated obliquely toward suture, not in

form of angle with opposite elytron; Guatemala .... H. puncticollis Sharp, p. 130
14' Elytral margin, viewed posteriorly, elevated obliquely toward suture, in form of

angle with opposite elytron (Fig. 54E) 15

15 (14') Profemur with carina on inner surface near base 16

1 5' Profemur without carina on inner surface near base 18

16 (15 ) Pronotum shiny, finely sparsely punctate, punctures separated by two to three

times puncture diameter; plaques absent; aedeagus as illustrated (Fig. 38B);

Colombia H. scintillabella, new species, p. 118

16' Pronotum dull, coarsely densely punctate, punctures separated by less than

puncture diameter; plaques present 17

17 (16') Pronotum unicolorous dark brown, lateral depressed areas microreticulate;

aedeagus as illustrated (Fig. 39A); Peru H. pavicula, new species, p. 123

17' Pronotum with dark brown, rectangular macula on disc, remainder testaceous,
lateral depressed areas not microreticulate; aedeagus as illustrated (Fig. 38A);
highlands of southeastern Brazil H. scintillutea , new species, p. 119

18 (15') Plaques various shapes other than small ovals at posterior 0.20 of metasternum

19

18' Plaques absent or reduced to small ovals at posterior 0.20 of metasternum ... 23

Western Hemisphere Hydraenidae 67

19 (18 ) Plaques arcuate 20

19' Plaqes straight 21

20 (19) Plaques separated posteriorly by four times plaque width; aedeagus as

illustrated (Fig. 39D); Colombia H. colombiana, new species, p. 127

20' Plaques separated posteriorly by twice plaque width; Brazil

H. plaumanni d’Orchymont, p. 129

21 (19') Plaques subtriangular, each plaque tapered from posterior to anterior 22

2 1' Plaques oval or subrectangular; aedeagus as illustrated (Fig. 37B); Chiapas,

Mexico H. campbelli, new species, p. 132

22 (21 ) Pronotal punctures on disc separated by less than puncture diameter; aedeagus

as illustrated (Fig. 39B); Argentina H. costiniceps, new species, p. 124

22' Pronotal punctures on disc separated by one to two times puncture diameter;

Bolivia H. germaini d’Orchymont, p. 126

23 (180 Plaques absent 24

23' Plaques reduced to small ovals at posterior 0.20 of metasternum 25

24 (23 ) Pronotal and elytral pubescence apparent; Durango, Mexico; females of

H. breedlovei , new species, p. 106

24' Pronotal and elytral pubescence obsolete; aedeagus as illustrated (Fig. 38C);

highlands of southeastern Brazil H. alterra, new species, p. 121

25 (230 Head with occipital area slightly emarginate in midline to receive scintilla . 27

25' Head lacking emargination in midline of occipital area to receive scintilla;

Arizona; females of H. arizonica, new species, p. 108

26 (25 ) Protibia stout, enlarged in apical 0.66; Oaxaca and Hidalgo, Mexico; females of

H. scintilla , new species, p. Ill

26' Protibia not stout, gradually enlarged from base to apex 27

27 (26') Pronotal punctation finer, sparser; Guatemala H. sordida Sharp, p. 129

27' Pronotal punctation coarser, denser, 28

28 (27 ) Size smaller, 1.36 mm or less; aedeagus as illustrated (Fig. 38D); highlands of

southeastern Brazil H. terralta, new species p. 122

28' Size larger, 1.68 mm or more; Arizona, Mexico 29

29 (28') Pronotal lateral margins more arcuate; size larger, about 1.88 mm; Arizona,

New Mexico, Texas, northern Mexico; females of H. leechi, new species p. 103
29' Pronotal lateral margins less arcuate; size smaller, about 1.68 mm; Jalisco,

Mexico; females of H. scopula, new species, p. 115

30 (1') Elytral punctures on disc random 31

30' Elytral punctures on disc serial 32

31 (30 ) Pronotal disc shiny, punctures separated by two to four times puncture

diameter; interstices smooth; aedeagus as illustrated (Fig. 39C); Mexico

H. zapatina, new species, p. 131

31' Pronotal disc dull; interstices rough; aedeagus as illustrated (Fig. 45B);

primarily coastal, Maryland to Florida H. youngi, new species, p. 1 50

32 (30') Pronotal reliefs dull, microreticulate; aedeagus as illustrated (Fig. 44A);

Chiapas, Mexico and Guatemala H. oblio, new species, p. 149

32' Pronotal reliefs shiny, non-microreticulate or extremely faintly so 33

33 (32') Metasternum with an anterior, median ridge (Fig. 48D) 34

33' Metasternum lacking an anterior, median ridge 42

Quaest. Ent., 1980, 16 (1,2)

68

Perkins

34 (33 ) Pronotum with anterior angles produced (Fig. 48C); broad, flat body: aedeagus

as illustrated (Fig. 45 A); Mexico, Nayarit to Oaxaca

H. cuspidicollis , new species, p. 162

34' Anterior angles of pronotum not produced 35

35 (34") Mesosternal intercoxal process narrow, width about 0.25 distance between

internal and median carinae; Durango, Mexico 36

35' Mesosternal intercoxal process broad, width subequal to distance between

internal and median carinae 37

36 (35 ) Pronotum with posterointernal foveolae more deeply impressed; elytra less

rounded at sides; aedeagus as illustrated (Fig. 47D)

H. bractoides, new species, p. 161

36' Pronotum with posteroexternal foveolae less deeply impressed; elytra more

rounded at sides; aedeagus as illustrated (Fig. 47C)

H. bractea, new species, p. 160

37 (35') Plaques separated by more than twice plaque width 38

31' Plaques separated by less than twice plaque width 39

38 (37 ) Plaques elevated; depression between plaques well developed; pronotal discal

punctures separated by two to three times puncture diameter; aedeagus as
illustrated (Fig. 47 A); Durango and Jalisco, Mexico

H. prieto, new species, p. 157

38" Plaques not elevated; depression between plaques slightly developed; pronotal
discal punctures separated by puncture diameter; aedeagus as illustrated
(Fig. 46A); Jalisco, Mexico H. crystallina, new species, p. 155

39 (370 Plaques separated by plaque width or less; aedeagus as illustrated (Fig. 46C);

Mexico, Mexico H. scolops, new species, p. 153

39' Plaques separated by more than plaque width 40

40 (390 Plaques elevated at lateral margins, relative to remainder of plaque; aedeagus as

illustrated (Fig. 47B); Durango, Mexico H. argutipes, new species, p. 158

40' Plaques not elevated at lateral margins, relative to remainder of plaque 41

41 (400 Metasternal ridge well developed, acute in cross-section; pronotal discal

punctures separated by puncture diameter; size larger, about 1.70 x 0.72 mm;

aedeagus as illustrated (Fig. 46D); Oaxaca, Mexico

H. oaxaca, new species, p. 152

41' Metasternal ridge weakly developed, rounded in cross-section; pronotal discal
punctures separated by twice puncture diameter; size smaller, about 1.36 x

0.60 mm; aedeagus as illustrated (Fig. 46B); Jalisco, Mexico

. ... H. mazamitla, new species, p. 1 56

42 (330 Plaques reduced to small ovals at posterior 0.17 of metasternum; aedeagus as

illustrated (Fig. 4 ID); Tamaulipas, Mexico H.exilipes, new species, p. 133

42' Plaques various, not reduced to small ovals at posterior 0.17 of metasternum . 43

43 (420 Plaques convergent anteriorly 44

43' Plaques parallel 47

44 (43 ) Plaques separated at anterior by about four times greatest width of plaque;

aedeagus as illustrated (Fig. 44B); northeastern United States

H. punctata LeConte, p. 148

44' Plaques separated at anterior by about twice greatest width of plaque 45

Western Hemisphere Hydraenidae

69

45 (44') Elytral intervals about 0.25 puncture diameter in width; size larger, about 1.57

x 0.68 mm; Brazil H. sahlbergi d’Orchymont, p.

45' Elytral intervals about puncture diameter in width; size smaller, about 1.30 x
0.58 mm

46 (450 Elytral margins, viewed posteriorly, turned slightly upward toward suture; body

form slightly broader; aedeagus as illustrated (Fig. 44C); primarily coastal,

eastern United States, Maryland to Texas H. spangleri, new species, p.

46' Elytral margins, viewed posteriorly, not turned upward toward suture; body
form slightly narrower; aedeagus as illustrated (Fig. 44D); Guadeloupe,
Jamaica, Costa Rica H. guadelupensis d’Orchymont p.

47 (43') Pronotal lateral margins not convergent from middle to anterior angles;

posterointernal foveolae very slightly developed; aedeagus as illustrated

(Fig. 64A); Venezuela, Guyana and Brazil H. hyalina, new species, p.

47' Pronotal lateral margins convergent from middle to anterior angles;

posteroexternal foveolae generally more apparent

48 (47') Pronotal posterointernal foveolae very lightly impressed or absent; form broad,

about 1.18 x 0.52 mm; pronotum finely, moderately densely punctate; aedeagus

as illustrated (Fig. 43C); Cuba H. decui Spangler, p.

48' Pronotal posterointernal foveolae well developed; pronotum more coarsely and
densely punctate

49 (48') Size smaller, about 1.16 mm long; aedeagus as illustrated (Fig. 43D); Brazil

H. orcula, new species, p.

49' Size larger, about 1.40 mm long; aedeagus as illustrated (Figs. 43A,B);

Honduras to Trinidad via mainland H. particeps, new species, p.

Key to marginicollis Group species of Western Hemisphere Hydraena

1 ( 0 ) Prosternal carina separated from procoxae by a narrow shelf; mesosternal

intercoxal process broad, width slightly greater than distance separating internal

and median carinae (Figs. 63 A, F ){geminya Subgroup)

1' Prosternal carina not separated from procoxae by a narrow shelf; mesosternal
intercoxal process narrow, width less than distance separating internal and
median carinae (Figs. 54B,I,63B) ( marginicollis Subgroup)

2 ( 1 ) Pronotal fascia occupying median 0.33; plaques very narrow, separated

posteriorly by eight times plaque width; aedeagus as illustrated (Fig. 64B);

Nayarit, Mexico H. vela , new species, p.

2' Pronotal fascia occupying median 0.50; plaques separated posteriorly by less
than three times plaque width

3 ( 2') Plaques less convergent anteriorly, nearly parallel, separated at anterior by

more than plaque length; aedeagus as illustrated (Fig. 64C); Chiapas, Mexico

H. chiapa , new species, p.

3' Plaques more convergent anteriorly, separated at anterior by less than plaque

length; aedeagus as illustrated (Fig. 64D); Oaxaca, Mexico

H. geminya, new species, p.

4 (1') Pronotum entirely testaceous or with testaceous borders and very faint light

brown macula on disc

141

46

146

145

179

48

144

49

140

142

2

4

206

3

207

209

5

Quaest. Ent., 1980, 16 (1,2)

70

Perkins

4'

5 (4)

5'

6 (5')

6'

7 (40

7

8 (7)

8'

9 (70
9'

10 (9)
10'

11 (10)

11'

12 (100

12'

13 (12)
13'

14 (130
14'

15 (120
15'

16 (150

Pronotal disc dark brown or black, usually with anterior and posterior margins

light brown or testaceous 7

Elytra with fine, close-set punctures in series; metasternum shallowly depressed
between plaques; aedeagus as illustrated (Fig. 43C); Cuba . . . H. decui Spangler, p.

144

Elytra with fine, sparse punctures which do not form definite rows;

metasternum deeply impressed between plaques; Panama 6

Metasternal plaques located at border of inverted, V-shaped depression; elytra

entirely brown; aedeagus as illustrated (Fig. 49C)

H. limpidicollis, new species, p. 167

Metasternal plaques located at border of inverted, U-shaped depression; elytra
brown with faint ochraceous macula on disc; aedeagus as illustrated (Fig. 49D)

H. newtoni, new species, p. 168

Elytra with at least some punctures on disc random, not forming discrete rows

8

Elytra with discal punctures in rows 9

Elytra of males greatly truncate, posterior margin of each elytron sinuate;
plaques not carinae at lateral margins; aedeagus as illustrated (Fig. 52B);

Trinidad, Guyana H. premordica, new species, p. 175

Elytra not truncate, posterior margin of each elytron not sinuate; plaques

carinate at lateral margins; aedeagus as illustrated (Fig. 58B); Colombia

H. anisonycha , new species, p. 191

Plaques absent or reduced to small ovals at posterior 0.20 or metasternum ... 10

Plaques various, not reduced to small ovals at posterior 0.20 of metasternum 17

Plaques absent 11

Plaques small ovals 12

Elytral intervals and punctures equal in width; size smaller, about
1.48 x 0.60 mm; aedeagus as illustrated (Fig. 55A); eastern United States,

primarily coastal, from New Jersey to Louisiana

H. marginicollis Kiesenwetter, p. 184

Elytral intervals 0.50 puncture width; size larger, about 1.56 x 0.56 mm;
aedeagus as illustrated (Fig. 55C); eastern North America from Texas to

southern Mexico H. pulsatrix, new species, p. 187

Size about 1.40 - 1.45 mm 13

Size about 1.26 - 1.35 mm 15

Aedeagus as illustrated (Fig. 49 A); Argentina

H. tucumanica, new species, p. 165

Aedeagus not as above; Central America 14

Aedeagus as illustrated (Fig. 55D); southern Mexico and Guatemala

H. longicollis Sharp, p. 190

Aedeagus as illustrated (Fig. 55B); Costa Rica

H. turrialba, new species, p. 186

Elytral intervals and punctures equal in width; aedeagus as illustrated

(Fig. 51 A); Guatemala H. guatemala, new species, p. 169

Elytral intervals about 0.50 puncture diameter 16

Aedeagus as illustrated (Fig. 58 A); Peru H. peru, new species, p. 190

Western Hemisphere Hydraenidae

71

16' Aedeagus as illustrated (Fig. 60B); Costa Rica

H. nevermanni, new species, p. 195

17 (9') Plaques elevated at anterior or along entire length 18

17' Plaques not elevated 20

18 (17 ) Plaques carinate along entire length; pronotal discal punctures separated by

three to six times puncture diameter; very shiny species; aedeagus as illustrated

(Fig. 52A); Mexico H. grouvellei d’Orchymont, p. 174

18' Plaques elevated at anterior; pronotal discal punctures separated by one to three

times puncture diameter 19

19 (180 Metatibiae of males greatly expanded (Figs. 61A,B); metatibiae of females

widest at midlength; aedeagus as illustrated (Fig. 62B); Chiapas, Mexico ....

H. d-destina , new species, p. 200

19' Metatibiae of both sexes gradually enlarging from base to apex; aedeagus as

illustrated (Fig. 52D); Matto Grosso, Brazil

H. anaphora , new species, p. 178

20 (170 Metatibiae of males expanded; metatibiae of females widest at midlength;

aedeagus as illustrated (Fig. 62C); Chiapas, Mexico

H. barricula, new species, p. 202

20' Metatibiae of both sexes gradually enlarged from base to apex 21

21 (200 Plaques separated posteriorly by greatest width of a plaque; aedeagus as

illustrated (Fig. 5 IB); Haiti H. haitensis, new species, p. 171

21' Plaques separated posteriorly by more than greatest width of a plaque 22

22 (2T) Plaques triangular 23

22' Plaques oval or elongate 24

23 (22 ) Size larger, about 1.54 x 0.68 mm; aedeagus as illustrated (Fig. 53D);

Guadeloupe H. insularis d’Orchymont, p. 183

23' Size smaller, about 1.48 x 0.64 mm; aedeagus as illustrated (Fig. 5 ID); Cuba .

H. per kinsi Spangler, p. 172

24 (220 Aedeagus with parameres originating below midlength of main-piece 25

24' Aedeagus with parameres originating above midlength of main-piece 30

25 (24 ) Aedeagus with left paramere as long as main-piece (Fig. 64A); Venezuela,

Guyana and Brazil H. hyalina, new species, p. 179

25' Aedeagus with left paramere shorter than main-piece 26

26 (250 Aedeagus with left paramere originating at same distance from base as right

paramere 27

26' Aedeagus with left paramere originating above insertion of right paramere . . 28

27 (26 ) Aedeagus with right paramere extended to apex of main-piece (Fig. 49B);

Ecuador H. quechua, new species, p. 166

27 ' Aedeagus with right paramere not extending to apex of main-piece (Fig. 5 1C);

Mexico H. mexicana, new species, p. 171

28 (260 Aedeagus expanded in lateral view (Fig. 53C); Trinidad

H. trinidensis, new species, p. 182

28' Aedeagus not expanded in lateral view 29

29 (280 Aedeagus with terminal-piece shorter than distance separating base of

main-piece and insertion of right paramere (Fig. 52C); Ecuador

H. jivaro, new species, p. 176

Quaest. Ent., 1980, 16 (1,2)

72

Perkins

29' Aedeagus with terminal-piece longer than distance separating base of
main-piece and insertion of right paramere (Figs. 53A,B); Brazil and Venezuela
H. browni, new species, p.

30 (24') Aedeagus without a slender apical process (Fig. 62D); Chiapas, Mexico

H. splecoma, new species, p.

30' Aedeagus with a slender apical process

31 (300 Aedeagus with left paramere longer than right

3 V Aedeagus with right paramere longer than left

32 (31 ) Size larger, about 1.60 x 0.68 mm; aedeagus as illustrated (Fig. 60A); Central

America H. colymba, new species, p.

32' Size smaller, about 1.30 x 0.52 mm; aedeagus as illustrated (Fig. 62A);
southern Mexico and Guatemala H. sabella, new species, p.

33 (3F) Size larger, about 1.44 x 0.60 mm; aedeagus as illustrated (Fig. 60C); Costa

Rica H. malkini, new species, p.

33' Size smaller, about 1.14 x 0.48 mm; aedeagus as illustrated (Fig. 60D); Panama
H. pontequula, new species, p.

180

204

31

32

33

193

199

196

198

The circulata Group

Members of the circulata Group are characterized by form of the ventral surface of the
head, which has the posterior margin of the genae in the form of a transverse ridge (Fig. 21 H).
Additionally, adults have the intercoxal segment of the abdomen (Fig. 2 ID) concave, with the
posterior margin arcuate. These characteristics are in contrast to those of the leechi and
marginicollis Groups whose adults lack the genal ridge and have a flat intercoxal segment (cf.
Figs. 48 D,E).

The aedeagus, which corroborates the proposed monophyly of circulata Group species, is
very simple compared to that of males in the leechi and marginicollis Groups. The parameres
originate at base of the median piece and are generally slender and with the apex enlarged very
slightly, although they are flattened in males of a few species. The main-piece is tubular for
most of its length, flattened at apex. Interspecific variation generally involves shape of the apex,
in males of a few species also shape of the main-piece, and density and length of the setae on
the parameres(cf. Figs. 22A, 24A, 28A).

Externally this group is quite uniform, requiring referral to the male genitalia for positive
species assignment of adults. Those of most species have well developed plaques and relatively
coarse, microreticulate pronotum and head. Adults of a number of species show a tendency
toward subcarinate elytral intervals. Adults of only a single species, H. quadricurvipes , has
modified legs, the legs of the other species being straight and lacking the various expansions,
excavations, or processes seen in the leechi and marginicollis Groups.

Geographically, the circulata Group is entirely Nearctic, with the greatest concentration of
species in the mountains of the Pacific coast states of the United States. A few species have a
circular distribution pattern around the Great Basin, with the circular pattern interrupted by
the barrier imposed by the arid regions of southeastern California and southwestern Arizona
(see for example Hydraena circulata , Fig. 23 A).

I have arranged the circulata Group in four complexes: circulata , angulicollis, atlantica
and pennsylvanica. These complexes are based upon similarity of aedeagal structure, discussed

Western Hemisphere Hydraenidae

73

Figs. 21 A - H, Hydraena circulata. (A) dorsal habitus. (B) ventral habitus. (C) pronotum (AEF = anteroextemal
foveola, M = margin, PEF = posteroexternal foveola, P1F = posterointernal foveola). (D) metasternum (arrows indicate
metacoxal sensillum and intercoxal sternite). (E) prosternum. (F) protibia. (G) elytra, posterior aspect. (H) head, ventral
aspect (arrow indicates genal ridge).

Quaest. Ent., 1980, 16(1,2)

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Perkins

in the phylogeny section.

The circulata Complex

1 . Hydraena circulata new species
(Figs. 101,21 A-H,22D,E,23A,148C,164A)

Type-locality. - Little Chico creek at School road, E. of Forest Ranch, 2300 feet, Butte
County, California.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. Hugh B. Leech collected these specimens September 1, 1961. Paratypes (790) are
listed in the appendix.

Diagnosis. - Only males can be reliably assigned to Hydraena circulata , on the basis of
genitalic features.

Description. — Form : Elongate. Size: Holotype 1.80 mm long, 0.72 mm wide. Color. Dorsal surface dark brown.
Maxillary palpi brown; antennae testaceous. Ventral surface dark brown except legs, elytral epipleura and inflexed margin
of pronotum, brown. Head : Length 0.24 mm. Width 0.44 mm. Frons punctation coarse, punctures separated by 0.50
puncture diameter, or less; microreticulation both in punctures and on interstices; surface dull. Frontoclypeal suture
arcuate to rear. Clypeus microreticulate except at anterior margin. Labroclypeal suture straight across middle when
viewed from above. Labrum bilobed, microreticulate, each lobe asymmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2,3 and 4, respectively:
0.26/0.12/0.20; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral and medial surfaces arcuate, widest slightly past midlength. Mentum wider than long,
surface moderately shining, microreticulate. Submentum microreticulation similar to mentum. Genae moderately dull,
finely microreticulate, lateral area of each gena with well developed foveola; posterior ridge well developed. Postgena
microreticulation slightly smaller than that of submentum. Last five antennomeres pubescent. Eyes 0.20 interocular
distance in width. Thorax: Pronotum length at midline 0.36 mm; maximum width (at approximately midlength) 0.52 mm;
sides margined, denticulate; sides moderately produced at middle, slightly sinuate and slightly convergent to anterior
angle, sinuate and convergent to posterior; anterior border 0.44 mm wide, straight and nearly perpendicular to midline in
lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.48 mm wide, slightly arcuate to rear.
Posterointernal foveolae moderately developed; punctures in foveola closer together than those on disc. Antero- and
posteroexternal foveolae confluent, sides of pronotum explanate. Transverse foveola moderately developed, punctures
closer together than punctures on disc. Disc dull, punctation coarse, punctures deeply impressed, separated by 0.50
puncture diameter; microreticulation both in larger punctures and on interstices; most punctures with seta extended above
cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina not produced anteriorly as very short spine; coxae
separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae
divergent from anterior to posterior; median carina not extended to base of intercoxal process; intercoxal process relatively
narrow, sides tapered, apex subacute, width near apex 0.33 distance between internal and median carinae. Metasternum
with low ridge posterior to intercoxal process; plaques well developed, straight, convergent moderately from posterior to
anterior; plaques 0.50 length of metasternum in midline; width of each plaque slightly less than width of intercoxal process
at its mid-length; plaques separated posteriorly by approximately twice plaque width; plaques separated anteriorly by
plaque width; plaques flat in cross section. Elytra : Length 1.20 mm. Maximum width (at midlength) 0.72 mm. Surface
moderately shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most punctures
rectangular; intervals elevated, width approximately equal to 0.33 puncture width, also interstices between adjacent
punctures of a row; each puncture with seta. Explanate margin moderately developed, ended near apices, with extremely
fine, well separated serrations along entire margin; serrations larger near anterior angles. Elytral apices, in dorsal aspect,
gradually rounded; in posterior aspect, elytral margin elevated very slightly obliquely toward suture, in form of slight angle
with opposite elytron. Abdomen. Intercoxal segment concave. Glabrous segments at apex only moderately produced.
Sternum 7 very slightly emarginate at apex. Legs: Without apparent modification. Genitalia : Aedeagus as illustrated
(Figs. 22D,E). (353 examined).

Variation. - Throughout most of its extensive range, adults of this species have the pronotal
punctation coarse, the punctures separated by thin walls. In Arizona specimens, however, the
pronotum is much smoother and more reflective, the punctures separated by about 0.50 the

Western Hemisphere Hydraenidae

75

diameter of a puncture. Many of these Arizona specimens are light brown, although some are
dark brown or black. Specimens from parts of the range other than Arizona are generally dark
brown or black. The parameres of specimens from Arizona and Colorado (Fig, 22E) are blunt
at the apex and have the setae denser and distributed further down the paramere. From the
external and genitalic details, apparently gene exchange rate between the Arizona and southern
California populations (Fig. 23A) is very low, due to the barrier imposed by the southwestern
deserts.

Natural History. - Most records cite “stream”, “creek” or “river” as part of the locality
description. More unusual habitat descriptors include “pool in drying up stream”, “foul pool,
dried bed of creek” “puddle in grassy slope”, “ephemeral stream”, “pond”, “Ranunculus pool”,
“seepage trickle over gravelly soil”, “seepage over rocks and small cliffs”, “clear water pools in
gravel and stones of otherwise dry and shaded creek”, “ex seepage full of dead conifer leaves”,
“along lake shore”, and “bog”. Elsewhere (Perkins, 1976) I discussed the microhabitat
preferences and associates of Hydraena circulata in southern California ( Hydraena circulata
and H. vandykei are discussed in that paper under the designation “ Hydraena sp.”). My
research revealed that Hydraena circulata is primarily a psammolotic species. The descriptors
cited above probably represent those microhabitats which are secondary, being used at times of
overpopulation, or those microhabitats that the beetles are forced into as streams become dry.

Distribution. - (Figs. 23A,162A). Hydraena circulata is the most widespread and one of the
most common western species of the circulata Group. Distribution forms a circular pattern,
from southern California and northern Baja California northward to British Columbia, then
southward in the Rocky Mountains to southern Arizona.

Etymology. - Latin, circulata (forming a circle). The name refers to the geographical
distribution pattern.

2. Hydraena arenicola new species
(Figs. 22C,27D,164A)

Type-locality. - 6.9 miles N. Middletown, on highway 29, Lake County, California.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. Hugh B. Leech collected these specimens February 20, 1955. Paratypes (433) are
listed in the appendix.

Diagnosis. - The aedeagus must be studied to reliably recognize males of H. arenicola.

Description. — Form: Elongate. Size: Holotype 1 .76 mm long, 0.72 mm wide. Color: Dorsal surface dark brown.
Maxillary palpi and antennae brown. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of
pronotum, brown. Head: Length 0.24 mm. Width 0.42 mm. Frons punctation coarse, punctures separated by 0.50
puncture diameter, or less; microreticulation present both in punctures and interstices; surface dull. Frontoclypeal suture
arcuate to rear. Clypeus microreticulate except at anterior margin. Labroclypeal suture straight across middle in dorsal
aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at approximately
midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.26/0.10/0.20; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral and medial surfaces arcuate, widest near midlength. Mentum wider than long, surface
moderately shining, microreticulate. Submentum microreticulate. Genae moderately shining, punctulate; lateral area of
each gena with well developed foveola; posterior ridge well developed. Postgena with microreticulation slightly larger than
that of submentum. Last five antennomeres pubescent. Eyes 0.20 interocular distance in width. Thorax: Pronotum length
at midline 0.36 mm; maximum width (at approximately midlength) 0.52 mm; sides margined, denticulate; sides
moderately produced at middle, slightly sinuate and slightly convergent to anterior angle, sinuate and convergent to
posterior; anterior border 0.42 mm wide, straight and nearly perpendicular to midline in lateral 0.25 moderately arcuate to
rear in middle 0.50; posterior border 0.44 mm wide, slightly arcuate to rear. Posterointernal foveolae well developed;

Quaest. Ent., 1980, 16 (1,2)

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Perkins

Figs. 22A - E, Aedeagi of Hydraena holotypes. (A) H. tuolumne. (B) H. oecidentalis. (C) H. arenicola. (D) H. circulata.
(E) parameres of H. circulata (from (top to bottom) Blaine County, Montana; Huerfano County, Colorado; and Cochise
County, Arizona).

Western Hemisphere Hydraenidae

77

Figs. 23 A - F, Geographical distributions of Hydraena species. (A) H. circulata. (B) H. occidentalis. (C) H. vandykei.
(D) H. calif ornica • and H. yosemitensis ★ . (E) H. tuolumne • and H. mignymixys ★ . (F) H. sierra.

Quaest. Ent., 1980, 16 (1,2)

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punctures in foveola closer together than those on disc. Antero- and posteroexternal foveolae confluent, sides of
pronotum explanate. Transverse foveola moderately developed, punctures closer together than punctures on disc. Disc
dull, punctures separated by 0.50 puncture diameter, or less; microreticulation present in large punctures only, absent
from interstices; most punctures with distinctive seta extended above cuticle in dry specimens. Scintilla absent.
Prosternum carinate, carina not produced anteriorly as very short spine; coxae separated by thin, median carina; carina
sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior;
median carina not extended to base of intercoxal process; intercoxal process relatively broad, sides tapering, apex
subacute, width near apex 0.50 distance separating internal and median carinae. Metasternum with plaques well
developed, straight, convergent moderately from posterior to anterior; plaques 0.50 length of metasternum in midline;
width of each plaque 0.50 width of intercoxal process at its midlength; plaques separated posteriorly by slightly greater
than plaque width; plaques separated anteriorly by slightly less than plaque width; plaques flat in cross section. Elytra:
Length 1.12 mm Maximum width (at midlength) 0.72 mm. Surface dull, disc with 10 rows of punctures between suture
and humeral callus, rows quite regular; most punctures rectangular; intervals elevated, width approximately equal to
0.50 puncture width, as are interstices between adjacent punctures of a row; each puncture with seta. Explanate margin
moderately developed, ended near apices, with serrations near anterior angles and apices. Elytral apices, in dorsal
aspect, gradually rounded; in posterior aspect elytral margin elevated obliquely toward suture, in form of angle with
opposite elytron. Abdomen: Intercoxal segment concave. Glabrous segments at apex weakly produced. Sternum 7 very
slightly emarginate at apex. Legs: Without apparent modification. Genitalia: Aedeagus as illustrated (Fig. 22C) (195
examined).

Natural History. - The great majority of locality records cite “stream” or “creek” as the
macrohabitat. More unusual notations include “pool in drying up stream”, “foul pool dried bed
of creek”, “ephemeral stream”, “moss-edged rock pools in running stream, open area”, “clear
water pools in gravel and stones of otherwise dry and shaded creek bed”, and “small pool in
drying Darlingtonia bog”.

Distribution. - (Figs. 27D,164A). Northern Oregon south to southern California. Greatest
population density in coastal mountain ranges of northern California.

Etymology. - Latin, arena (sand) plus icola (dweller). This name refers to the psammolotic
habits of this species.

3. Hydraena Occident alis new species
(Figs. 22B, 23B, 164A)

Type-locality. - Bloody Run Creek, 7 miles E. of Route 101 on Longvale-Covelo road, 1 100
feet, Mendocino County, California.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. These specimens were collected by Hugh B. Leech July 18, 1968. Paratypes (221) are
listed in the appendix.

Diagnosis. - Aedeagi must be studied to identify males of this species.

Description. — Form: Elongate. Size: Holotype 2.04 mm long, 0.88 mm wide. Color: Dorsal surface dark brown
except narrow border of pronotum and explanate margin of elytra testaceous. Maxillary palpi testaceous; antennae
testaceous. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum brown. Head:
Length 0.28 mm Width 0.48 mm. Frons dull, punctation coarse, punctures separated by 0.50 puncture diameter, or less.
Clypeus microreticulate. Labroclypeal suture straight across middle in dorsal aspect. Labrum bilobed, microreticulate,
each lobe symmetrical arc; median emargination ended well above midlength of labrum. Maxillary palpus with following
lengths(mm.) of palpomeres 2, 3 and 4, respectively: 0.32/0.12/0.26; second segment bending outward at approximately
midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly straight in basal
0.33 arcuate in apical 0.66 median surface arcuate; apical segment widest near apical 0.33, Mentum wider than long,
surface moderately shining, finely microreticulate. Submentum microreticulate. Genae weakly shining; lateral area of
each gena with well developed foveola; posterior ridge well developed. Postgena with microreticulation smaller than that of
submentum. Last five antennomeres pubescent. Eyes slightly less than 0.20 interocular distance in width. Thorax:
Pronotum length at midline 0.44 mm; maximum width (at approximately midlength) 0.62 mm; sides margined,
denticulate; sides moderately produced at middle, sinuate and slightly convergent to anterior angle, sinuate and convergent
to posterior; anterior border 0.52 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately
arcuate to rear in middle 0.50; posterior border 0.5 2 mm wide, slightly arcuate to rear. Posterointernal foveolae slightly
developed; punctures in foveola similar to those on disc. Antero- and posteroexternal foveolae confluent, in form of

Western Hemisphere Hydraenidae

79

explanate sides. Transverse foveola slightly developed, with punctures separated by thin walls. Disc dull, punctures
relatively large and deeply impressed, separated by thin walls; most punctures finely microreticulate; most punctures
with distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina not produced
anteriorly as very short spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect.
Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to base of
intercoxal process; intercoxal process relatively broad, sides tapered, apex rounded, width near apex 0.66 distance
between internal and median carinae. Metasternum with carina in midline between anterior region of plaques and
intercoxal process; plaques well developed, straight, convergent from posterior to anterior; plaques 0.57 length of
metasternum in midline; width of each plaque 0.66 width of intercoxal process at its midlength; plaques separated
posteriorly by approximately plaque width; plaques separated anteriorly by 0.50 plaque width; plaques flat in cross
section; slightly elevated, oblique ridge lateral to each plaque. Elytra: Length 1.40 mm. Maximum width (at midlength)
0.88 mm. Surface dull, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most
punctures rectangular; intervals well elevated, width approximately 0.50 puncture width, as are interstices between
adjacent punctures of a row; each puncture with seta. Explanate margin well developed, ended near apices, with
serrations near anterior angles and in posterior 0.33. Elytral apices in dorsal aspect gradually rounded; posteriorly,
elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment
concave. Glabrous segments at apex very weakly produced. Segment 7 without emargination at apex. Legs: Without
apparent modification. Genitalia: Aedeagus as illustrated (Fig. 22B) (100 examined).

Natural History. - Stream or creek habitats are mentioned in most locality records.
Unusual habitat notations include “ex moss in bed of dried-up woodland pool”, “margin of
Typha pool”, and “ephemeral pond”.

Distribution. - (Figs. 23B,164A). British Columbia, Washington, Oregon and California.

Etymology. - Latin, occidentalis (of the west). This name refers to the geographical
distribution.

4. Hydraena tuolumne new species
(Figs. 22A, 23E, 164 A)

Type-locality. - Tributary of Niagara Creek, Forest Campground, Tuolumne County,
California.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. Hugh B. Leech collected these specimens September 21, 1963. Paratypes (46) are
listed in the appendix.

Diagnosis. - Male genitalic characteristics are the only totally reliable diagnostic features.

Description. — Form: Elongate. Size: Holotype 1.88 mm long, 0.84 mm wide. Color: Head with dorsal surface and
labrum dark brown; maxillary palpi testaceous except apices brown; antennae testaceous. Pronotum brown except dark
brown macula on disc. Elytra brown. Ventral surface dark brown except legs, elytral epipleurae and inflexed margin of
pronotum, brown. Head: Length 0.24 mm. Width 0.44 mm. Frons dull, punctation coarse, punctures separated by 0.33
puncture diameter, or less; microreticulation both in punctures and on interstices. Frontoclypeal suture straight across
middle in dorsal aspect. Labrum bilobed, microreticulate, each lobe asymmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.32/0.12/0.24; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface nearly straight in basal 0.33 arcuate in apical 0.66 median surface evenly
arcuate; palpomere 4 widest slightly past midlength. Mentum wider than long, surface moderately shining,
microreticulate. Submentum microreticulation similar to mentum. Genae dull, finely microreticulate, lateral area of each
gena with well developed foveola; posterior ridge well developed. Postgena with microreticulation slightly smaller than that
of submentum. Last five antennomeres pubescent. Eyes 0.20 interocular distance in width. Thorax: Pronotum length at
midline 0.44 mm; maximum width (at approximately midlength) 0.58 mm; sides margined, denticulate; sides moderately
produced at middle, slightly sinuate and slightly convergent to anterior angle, sinuate and convergent to posterior; anterior
border 0.46 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle
0.50; posterior border 0.50 mm wide, slightly arcuate to rear. Posterointernal foveolae weakly developed; punctures in
foveola similar to those on disc. Antero- and posteroexternal foveolae confluent. Transversal foveola moderately developed,
many punctures in this area confluent. Disc dull, punctation coarse, punctures deeply impressed, many confluent;
microreticulation quite evident in larger punctures, absent from interstices; most punctures with a distinctive seta which
extends above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina not produced anteriorly as very short
spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and

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Figs. 24A - D, Aedeagi of Hydraena species. (A) H. quadricurvipes , holotype. (B) H. quadricurvipes , variant from
Monroe County, Indiana. (C) H. appalachicola, holotype. (D) H. angulicollis , Hamilton County, New York.

Western Hemisphere Hydraenidae

81

external carinae divergent from anterior to posterior; median carina not extended to base of intercoxal process;
intercoxal process relatively narrow, sides tapered, width near apex 0.50 distance between internal and median carinae.
Metasternum with plaques well developed, straight, covergent moderately from posterior to anterior; plaques 0.50 length
of metasternum in midline; greatest width of each plaque subequal to width of intercoxal process at its midlength;
plaques separated posteriorly by slightly less than plaque width; plaques separated anteriorly by 0.50 basal width of
plaque; plaques flat in cross section; each plaque narrowed anteriorly. Elytra: Length 1.30 mm. Maximum width (at
midlength) 0.84 mm. Surface dull, disc with 10 rows of punctures between suture and humeral callus, rows quite
regular; most punctures rectangular; intervals elevated, width approximately equal to 0.50 puncture width, as are
interstices between adjacent punctures of a row; each puncture with a seta. Explanate margin moderately developed,
ended near apices, with serrations near anterior angles and apices. Elytral apices, in dorsal aspect, gradually rounded; in
posterior aspect elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen:
Intercoxal segment concave. Glabrous segments at apex weakly produced. Segment 7 almost truncate at apex. Legs:
Without apparent modification. Genitalia: Aedeagus as illustrated (Fig. 22A) (26 examined).

Natural History. - Most locality records mention flowing water habitats.

Distribution. - (Figs. 23E,164A). Restricted to the Sierra Nevada Mountains of California.
Etymology. - tuolumne , in reference to the type-locality.

Figs. 25 A - D, Geographical distributions of Hydraena species. (A) H. angulicollis. (B) H. atlantica • and Hr
appalachicola ★ . (C) H. pennsylvanica. (D) H. quadricurvipes • and H. ancylis ★ .

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The angulicollis Complex

5. Hydraena angulicollis Notman
(Figs. 24D,25A,164B)

Hydraena angulicollis Notman 1921:146 (holotype female in SI I; type-locality: Westfield, Chautauqua County, New

York).

Diagnosis. - Adults are generally darker, smaller and the pronotal punctures are more
widely separated than in adults of H. pennsylvanica and H. ancylis the other species from
eastern North America with which it can be confused. Additionally, H. angulicollis adults
generally do not have the elytral intervals elevated, whereas adults of the aforementioned
species do, more or less. Specimens with external characteristics approaching those of H.
pennsylvanica and H. ancylis can be reliably discerned only by referral to the aedeagus.

Description. — Form: Elongate oval. Size: Holotype 1 .80 mm long, 0.80 mm wide. Color: Head with dorsal surface
dark brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum dark brown except for narrow
testaceous border. Elytra dark brown. Ventral surface dark brown except legs, elytral epipleura and indexed margin of
pronotum, brown. Head: Length 0.24 mm. Width 0.44 mm. Frons punctation coarse, interstices between punctures thin
walls to 0.50 puncture diameter; microreticulation in punctures only, absent from interstices; interstices shining.
Frontoclypeal suture arcuate. Clypeus microreticulate except at anterior margin. Labroclypeal suture straight across
middle when viewed from above. Labrum bilobed, microreticulate; each lobe an asymmetrical arc; median emargination
ending at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4,
respectively: 0.30/0.10/0/20; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not
especially expanded; palpomere 4 with lateral and medial surfaces arcuate, widest near midlength. Mentum wider than
long, surface moderately shining, finely and closely punctulate except middle, impunctulate. Submentum evenly, finely
punctulate, punctures contiguous. Genae dull, finely punctulate; lateral area of each gena with well developed foveola;
posterior ridge well developed. Postgena with punctation smaller than that of submentum. Last five
antennomeres pubescent. Eyes 0.20 interocular distance in width. Thorax: Pronotum length at midline 0.42 mm;
maximum width (at approximately midlength) 0.58 mm; sides margined, denticulate; sides relatively slightly produced at
middle, slightly sinuate and slightly convergent to anterior angle, sinuate and convergent to posterior; anterior border
0.48 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50;
posterior border 0.50 mm wide, slightly arcuate to rear. Posterointernal foveolae slightly developed; punctures in foveola
closer together than those on disc, separated by thin walls. Antero- and posteroexternal foveolae confluent, in form of
explanate sides. Transverse foveola not developed, punctures in this area closer together than punctures on disc, separated
by thin walls. Disc moderately dull, interstices shining, punctures separated by thin walls to puncture diameter,
microreticulation only in punctures, absent from interstices; most punctures with distinctive seta extended above cuticle in
dry specimens. Scintilla absent. Prosternum carinate, carina not produced anteriorly as very short spine; coxae separated
by thin, median carina; carina imperceptible anterior to coxae; carina sinuate line in lateral aspect. Mesosternum with
internal and external carinae parallel; median carina not extended to base of intercoxal process; intercoxal process
relatively narrow, sides tapered; apex subacute, width near apex 0.50 distance between internal and median carinae.
Metasternum with plaques well developed, straight, converging moderately from posterior to anterior; plaques 0.50 length
of metasternum in midline; greatest width of each plaque subequal to width of intercoxal process at its midlength; each
plaque tapered slightly from posterior to anterior; plaques separated posteriorly by approximately plaque width; plaques
separated anteriorly by approximately plaque width; plaques flat in cross section. Elytra: Length 1.24 mm. Maximum
width (at midlength) 0.80 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows
quite regular; most punctures hexagonal; intervals not elevated, width approximately equal to 0.50 puncture width, as are
interstices between adjacent punctures of a row; each puncture with seta. Explanate margin moderately developed, ended
near apices, with serrations near anterior angles and in posterior 0.33. Elytral apices in dorsal aspect gradually rounded; in
posterior aspect elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen:
Intercoxal segment concave. Glabrous segments at apex not produced. Segment 7 not emarginate at apex. Legs: Legs
without apparent modification. Genitalia: Aedeagus as illustrated (Fig. 24D) (98 examined).

Variation. - Density of the pronotal punctures varies considerably. Most specimens have the
punctures more widely separated than that seen in H. pennsylvanica adults. As stated in the
diagnosis, H. angulicollis adults are also generally darker and smaller than those of H.
pennsylvanica. However, I have studied collections from various localities, especially from

Western Hemisphere Hydraenidae

83

Michigan, each of which I judged all of the specimens to be H. pennsylvanica on the basis of
external characteristics. Upon dissection these series were found to be composite. The aedeagi
of males of the two species are highly dissimilar and cannot be confused. I have examined 184
specimens (see appendix).

Natural History. - Locality descriptors include “leaf litter using a Berlese funnel”, “sifting
leaves”, “sphagnum, streamside alder swamp”, “in shore debris”, and “small lake edge”. I have
collected H. angulicollis in Maine, at the margin of a small stream. The microhabitat at that
locality consisted of sand and gravel which was bordered by sphagnum moss. Further study is
necessary to definitely demonstrate an affinity for sphagnum moss, which would be an unusual
habitat preference for a member of the circulata Group, and for the genus in general.

Distribution. - (Figs. 25 A, 164B). H. angulicollis is the only Hydraena with a
trans-Canadian distribution, ranging from Fort Simpson, Northwest Territories in Canada
southeastward to Maryland.

Remarks. - Although the holotype is a female, it is the externally distinctive form (see
variation), and I have no reservations concerning its identity.

6. Hydraena appalachicola new species
(Figs. 24C,25B,164B)

Type-locality. - Two miles S. Mountain Grove, Blowing Springs public camp, Bath County,
Virginia.

Type-specimens. - The holotype male is deposited in USNM. My wife Maureen and I
collected this specimen June 3, 1973. The allotype, which is also deposited in USNM is
labelled: 12 miles S. Williamsville, Bath County, Virginia, M. E. and P. D. Perkins. One male
paratype with same data as the holotype is in PDP. Two male and one female paratypes, also
deposited in my collection, are labelled: 5 miles NE New Paltz, Ulster County, New York, P.
D. Perkins.

Diagnosis. - These attractive specimens are easily distinguished from other members of the
circulata Group by the non-serial arrangement of the punctures on the elytral disc. Only adults
of H. mignymixys , a California species, also have some non-serial elytral punctures, but differ
greatly in body form, color and sculpture. The following features make the pronotum of H.
appalachicola adults very distinctive: (1) the disc has a rectangular, black or dark brown
macula which is surrounded by, and contrasts with, the testaceous borders, (2) the punctures
are rather coarse, but are apparently not microreticulate and are well separated by the very
shiny interpunctal areas, and (3) the sides in the posterior are deeply incised.*

Description. — Form: Elongate oval. Size: Holotype 1.56 mm long, 0.76 mm wide. Color: Head with dorsal surface
dark brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous except for
transverse, rectangular, dark brown macula on disc. Elytra brown. Ventral surface dark brown except legs, elytral
epipleura and inflexed margin of pronotum, testaceous. Head: Length 0.22 mm. Width 0.42 mm. Frons punctation coarse,
punctures separated by 0.50 puncture diameter; microreticulation on interstices and in punctures; surface moderately dull.
Frontoclypeal suture arcuate to rear. Clypeus finely microreticulate. Labroclypeal suture straight across middle in dorsal
aspect. Labrum bilobed, microreticulate; each lobe asymmetrical arc; median emargination ended at approximately
midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2,3 and 4, respectively: 0.24/0.08/0.18;
palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4
with lateral and medial surfaces arcuate, widest near basal 0.33. Mentum wider than long, surface moderately shining,
punctures fine, contiguous except in middle. Submentum evenly, finely punctulate, punctures contiguous. Genae
moderately shining, finely punctulate; area of each gena with a well developed foveola; posterior ridge well developed.
Postgena with punctation similar in size to that of submentum. Last five antennomeres pubescent. Eyes slightly less than
0.25 interocular distance in width. Thorax: Pronotum length at midline 0.40 mm; maximum width (at approximately
midlength) 0.56 mm; sides margined, denticulate; sides moderately produced at middle, slightly sinuate and slightly

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84

Perkins

convergent to anterior angle, sinuate and convergent to posterior; anterior border 0.48 mm wide, straight and nearly
perpendicular to midline in lateral 0.25 moderately arcuate to rear in middle 0.50 posterior border 0.44 mm wide,
slightly arcuate to rear. Posterointernal foveolae moderately developed; punctures in foveola closer together than those
on disc. Posteroexternal foveola moderately developed. Interfoveolar depression moderately developed. Area between
external foveolae moderately elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped,
extended across slightly less than 0.33 width of anterior region of pronotum. Transverse foveola moderately developed,
punctures closer together than punctures on disc. Disc shining, punctures deeply impressed, separated by thin walls to
0.50 puncture diameter; some punctures with seta extended above cuticle in dry specimens. Scintilla absent. Prosternum
carinate, carina not produced anteriorly as very short spine; coxae separated by thin, median carina; carina a sinuate
line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median
carina not extended to base of intercoxal process; intercoxal process relatively narrow, sides tapered apex subacute,
width near apex 0.50 distance between internal and median carinae. Metasternum with plaques well developed, slightly
arcuate; plaques 0.50 length of metasternum in midline; width of each plaque subequal to width of intercoxal process at
its midlength; plaques separated by approximately twice plaque width; plaques flat in cross section. Elytra: Length
1.08 mm. Maximum width (at midlength) 0.76 mm. Surface shining, disc with 10 rows of punctures between suture
and humeral callus, however, rows somewhat irregular with serial arrangement of punctures ceasing in places; punctures
large, intervals reduced to thin, irregular walls, interstices between adjacent punctures of a row much larger, frequently
equal puncture diameter; most punctures with seta. Explanate margin moderately developed, ended near apices, with
fine serrations in anterior and posterior 0.33. Elytral apices, in dorsal aspect gradually rounded; in posterior aspect
elytral margin not elevated obliquely towards suture, not in form of angle with opposite elytron. Abdomen: Intercoxal
segment concave. Glabrous segments at apex weakly produced. Segment 7 without emargination at apex. Legs: Without
apparent modification. Genitalia: Aedeagus as illustrated (Fig. 24C)(4 examined).

Variation. - No significant variation was noted in the six specimens studied.

Natural History. - The specimens collected at the type-locality were in a sandy area of a
stream outwash in the mountains of Virginia (Fig. 189A). The specimen from Bath County, 12
miles S. Williamsville, was collected at the margin of a small stream, the substratum of which
consisted primarily of small, smooth slate fragments; this specimen was found in association
with a large population of Limnebius, primarily L. ozapalachicus , but also including L.
discolor Casey and L. richmondi, new species (Fig. 193B). The three specimens from Ulster
County, New York, were in a small sandy area at the margin of a very rapid, very cold brook
during winter.

Distribution. - (Figs. 25B,164B). Presently known from the Appalachian Mountains in the
states of Virginia and New York.

Etymology. - appalachian plus icola (dweller). Named in reference to the geographical
distribution.

7. Hydraena nigra Hatch, new status
(Figs. 27F,29D,164B)

Hydraena vandykei niger Hatch, 1965:20 (holotype male in UWA; type-locality: Galena, Blaine County, Idaho).

Diagnosis. - The carinate metasternal plaques serve as diagnostic features for these black,
relatively smooth members of the circulata Group. Refer to the section on variation for further
comments.

Description. — Form: Elongate oval. Size: Holotype 2.00 mm long, 0.76 mm wide. Color: Dorsal surface black.
Maxillary palpi testaceous; antennae testaceous. Ventral surface dark brown except legs, elytral epipleura and inflexed
margin of pronotum, brown. Head: Length 0.24 mm. Width 0.42 mm. Frons punctation moderately coarse, punctures
separated by 0.50 puncture diameter, or greater; microreticulation only in punctures, absent from interstices; interstices
shining. Frontoclypeal suture arcuate to rear. Clypeus microreticulate except at anterior margin. Labroclypeal suture
straight across middle when viewed from above. Labrum bilobed, microreticulate, each lobe symmetrical arc; median
emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively; 0.28/0.10/0.22; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral and medial surfaces slightly arcuate, widest past
midlength. Mentum wider than long, surface moderately shining, microreticulate. Submentum microreticulation similar to
mentum. Genae dull, microreticulate, lateral area of each gena with a well developed foveola; posterior ridge well

Western Hemisphere Hydraenidae

85

developed. Postgena with microreticulation slightly smaller than that of submentum. Last five antennomeres pubescent.
Eyes 0.20 interocular distance in width. Thorax: Pronotum length at midline 0.40 mm; maximum width (at
approximately midlength) 0.56 mm; sides margined, denticulate; sides moderately produced at middle, straight and
slightly convergent to anterior angle, sinuate and convergent to posterior; anterior border 0.46 mm wide, straight and
nearly perpendicular to midline in lateral 0.25, moderately arcuate in rear in middle 0.50; posterior border 0.46 mm
wide, slightly arcuate to rear. Posterointernal foveolae well developed; punctures in foveola closer together than those on
disc. Posteroexternal foveola moderately developed. Interfoveolar depression moderately developed. Area between
external foveolae moderately elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped,
extended across slightly less than 0.33 width of anterior region of pronotum. Transverse foveola weakly developed, with
punctures separated by thin walls. Disc moderately shining, punctures microreticulate, generally separated by 0.50
puncture diameter although few in middle confluent; most punctures with distinctive seta extended above cuticle in dry
specimens. Scintilla absent. Prosternum carinate, carina not produced anteriorly into very short spine; coxae separated
by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent
from anterior to posterior; median carina extended to base of intercOxal process; intercoxal process relatively broad,
sides tapered, apex round, width near apex 0.66 distance between internal and median carinae. Metasternum with
plaques well developed, straight, carinate at posterior, convergent moderately from posterior to anterior; plaques 0.50
length of metasternum in midline; greatest width of each plaque 0.25 width of intercoxal process at its midlength;
plaques separated posteriorly by approximately six times plaque width; plaques separated anteriorly by twice plaque
width. Elytra: Length 1.24 mm. Maximum width (at midlength) 0.76 mm. Surface moderately shining, disc with 10
rows of punctures between suture and humeral callus, rows quite regular; most punctures irregularly shaped; intervals
not elevated, surface quite irregular, reflections interrupted, width approximately equal to 0.50 puncture diameter, as
are interstices between adjacent punctures of row; each puncture with seta. Explanate margin moderately developed,
ended near apices, with extremely fine, well separated serrations along entire margin, those near anterior and posterior
larger. Elytral apices, in dorsal aspect, gradually rounded; viewed posteriorly, elytral margin elevates slightly, obliquely
toward suture, in form of slight angle with opposite elytron. Abdomen: Intercoxal segment concave. Glabrous segments
at apex slightly produced. Segment 7 without emargination at apex. Legs: Without apparent modification. Genitalia:
Aedeagus as illustrated (Fig. 29D)(50 examined).

Variation. - Of the 116 specimens studied, only 13 from a single locality in Tuolumne
County, California did not have the metasternal plaques carinate. The plaques of these 13
specimens were, however, narrow and widely separated as is seen in the carinate forms. The
aedeagi from this locality did not differ significantly from those of the remaining specimens
studied.

Natural History. - Most locality descriptors mention “creek”, “stream” or “headwaters”,
although there is one citation each of “bog” and “in moss”. This suggests that this species is
primarily a lotic, psammophilous form. The fact that it has been collected at high elevations, as
much as 9500 feet in Colorado, plus its absence from the coastal ranges of California, Oregon
and Washington causes me to suspect that perhaps H. nigra is a cold adapted species.

Distribution. - (Figs. 27F,164B). Found in the Sierra Nevada Mountains of California
south to the San Gabriel Mountains and north to southern Oregon, and in the Rocky
Mountains from southern British Columbia south to New Mexico.

The atlantica Complex

8. Hydraena atlantica new species
(Figs. 25B,26B,150D,153A-C,165A)

Type-locality. - Plummers Island, Montgomery County, Maryland.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. Paul J. Spangler collected these specimens May 19, 1972. Paratypes (199) are
listed in the appendix.

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Perkins

Diagnosis. - Adults are readily distinguished from those of other members of the circulata
Group found in eastern North America by the dark brown pronotal macula which does not
extend into the lateral explanate areas. The aedeagus (Fig. 26B) must be studied to identify
teneral specimens.

Description. — Form: Elongate oval Size: Holotype 1.86 mm long, 0.80 mm wide. Color: Head with dorsal surface
very dark brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum with dark brown macula
on disc, not extended into lateral explanate areas; remainder of pronotum testaceous-orange. Elytra brown. Ventral surface
dark brown except legs, elytral epipleura and inflexed margin of pronotum brown. Head: Length 0.24 mm. Width
0.44 mm. Frons punctation coarse, microreticulate, interstices between punctures 0.50 puncture diameter; interstices
shining. Frontoclypeal suture weakly arcuate to rear. Clypeus microreticulate. Labroclypeal suture straight when viewed
from above. Labrum bilobed, microreticulate, each lobe asymmetrical arc; median emargination ending above midlength
of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively; 0.32/0.12/0.24;
palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4
with lateral and medial surfaces slightly arcuate, widest near midlength. Mentum wider than long, surface moderately
shining, finely punctulate. Submentum finely punctulate. Genae moderately shining with transverse impressions, lateral
area of each gena with well developed foveola, posterior ridge well developed. Postgena with punctation slightly larger than
that of submentum. Last five antennomeres pubescent. Eyes slightly less than 0.20 interocular distance in width. Thorax:
Pronotum length at midline 0.44 mm; maximum width (at approximately midlength) 0.58 mm; sides margined,
denticulate; sides moderately produced at middle, slightly sinuate and very slightly convergent to anterior angle, markedly
sinuate and markedly convergent to posterior; anterior border 0.50 mm wide, straight and nearly perpendicular to midline
in lateral 0.12, moderately arcuate to rear in middle 0.50, posterior border 0.48 mm wide, rather markedly arcuate to rear.
Posterointernal foveolae extremely slightly developed; punctures in foveola similar to those on disc. Antero- and
posteroexternal foveolae confluent, sides explanate and disc elevated, parallel-sided. Transverse foveola not developed,
punctures in this area somewhat closer together than punctures on disc. Disc relatively dull, but with interstices shining,
punctures large and deeply impressed, separated by narrow walls; most punctures with distinctive seta extended above
cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina not produced anteriorly as very short spine; coxae
separated by a thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae
divergent from anterior to posterior; median carina not extended to base of intercoxal process; intercoxal process relatively
narrow, sides tapered apex round, width near apex 0.33 distance between internal and median carinae. Metasternum with
plaques well developed, straight, convergent moderately from posterior to anterior; plaques 0.50 length of metasternum in
midline; width of each plaque subequal to width of intercoxal process at its midlength; plaques separated posteriorly by
approximately plaque width; plaques separated anteriorly by slightly less than plaque width; plaques flat in cross section;
shallow furrow lateral to each plaque. Elytra: Length 1.24 mm. Maximum width (at midlength) 0.80 mm. Surface
shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most punctures longer than
wide; intervals very slightly elevated, width approximately equal to 0.50 puncture diameter, as are interstices between
adjacent punctures of row; each puncture with seta. Explanate margin moderately developed, ended near apices, with well
develpped serrations near anterior angles and extremely fine, well separated serrations along remainder of margin. Elytral
apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin not elevated obliquely toward suture, not in
form of angle with opposite elytron. Abdomen: Intercoxal segment concave. Glabrous segments at apex very slightly
produced. Segment 7 without emargination at apex. Legs: Without apparent modification. Genitalia: Aedeagus as
illustrated (Fig. 26B)(106 examined).

Natural History. - Habitat descriptors include “woodland pond”, “pothole”, and “pasture
pool”, indicating that H. atlantica may be primarily a lentic adapted species. Most collections,
however, do not indicate habitat and the few mentioned above may or may not represent those
macrohabitats where H. atlantica reaches its greatest reproductive potential. A detailed study
of the natural history of this species is necessary to firmly establish its preferred habitat and
limiting environmental factors.

Distribution. - (Figs. 25B,165A). Eastern North America from Maine south to Virginia.

Etymology. - Latin, atlantica , in reference to geographical distribution and presumed
relationship to H. pacifica as indicated by aedeagal form.

9. Hydraena pacifica , new species
(Figs.26A,C-D,27A-C,165A)

Western Hemisphere Hydraenidae

87

Type-locality. - Tributary to Vance Creek, Trinity Valley, British Columbia, Canada.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. Hugh B. Leech collected these specimens October 3, 1946. Paratypes (634) are listed
in the appendix.

Diagnosis. - Aedeagal form is the only feature which can be consistently relied upon to
discriminate males of this species.

Description. — Form: Elongate-oval. Size: Holotype 1.96 mm long, 0.84 mm wide. Color: Head with dorsal surface
black; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum black except extremely narrow,
testaceous border at anterior and posterior. Elytra very dark brown, virtually black. Ventral surface dark brown except
legs, elytral epipleura and inflexed margin of pronotum, brown. Head: Length 0.26 mm. Width 0.6 mm. Frons moderately
coarsely punctate, surface moderately dull. Frontoclypeal suture arcuate to rear. Clypeus microreticulate at sides, shining
in midline. Labroclypeal suture straight when viewed from above. Labrum bilobed, microreticulate, each lobe symmetrical
arc; median emargination ended above midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.32/0.12/0.22; palpomere 2 bent outward at approximately midlength; apex of
palpomere 2 more expanded than norm; palpomere 4 with lateral surface slightly angulate, median surface evenly arcuate;
palpomere 4 widest slightly past midlength. Mentum wider than long, surface shining, finely microreticulate. Submentum
with punctation similar to mentum. Genae shining; lateral area of each gena with well developed foveola; posterior ridge
well developed. Postgena with punctation much smaller than that of submentum. Last five antennomeres pubescent. Eyes
0.20 interocular distance in width. Thorax: Pronotum length at midline 0.44 mm; maximum width (at approximately
midlength) 0.62 mm; sides margined, denticulate; sides moderately produced at middle, slightly arcuate and convergent to
anterior angle, sinuate and convergent to posterior; anterior border 0.48 mm wide, straight and nearly perpendicular to
midline in lateral 0.25, moderately arcuate to rear in middle 0.50 posterior border 0.52 mm wide, slightly arcuate to rear.
Posterointernal foveolae moderately developed; punctures in foveola closer together than those on disc. Posteroexternal
foveola well developed. Interfoveolar depression well developed. Area between external foveolae moderately elevated.
Anteroexternal foveolae well developed, each foveola slightly crescent shaped, occupying slightly less than 0.33 width of
anterior region of pronotum. Transverse foveola moderately developed, punctures separated by thin walls. Disc shining,
punctures moderate sized, deeply impressed, separated by thin walls near anterior and posterior borders, by puncture
diameter in middle; most punctures with distinctive seta extended above cuticle in dry specimens. Scintilla absent.
Prosternum very weakly carinate, carina not produced anteriorly as very short spine; coxae separated by thin, median
carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae parallel; median carina not
extended to base of intercoxal process; intercoxal process relatively narrow, sides tapered, apex acute, width near apex 0.25
distance between internal and median carinae. Metasternum with plaques well developed, straight, convergent moderately
from posterior to anterior; plaques 0.57 length of metasternum in midline; width of each plaque subequal to width of
intercoxal process at its midlength; plaques separated posteriorly by approximately plaque width; plaques separated
anteriorly by 0.50 plaque width; plaques flat in cross section. Elytra: Length 1.32 mm. Maximum width (at midlength)
0.84 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most
punctures rectangular; intervals elevated, width slightly less than 0.50 puncture diameter, interstices between adjacent
punctures of row generally narrower; each puncture with seta. Explanate margin moderately developed, ended near
posterior 0.10, with fine serrations near anterior angles and apices. Elytral apices in dorsal aspect gradually rounded; in
posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen:
Intercoxal segment concave. Glabrous segments at apex very slightly produced. Segment 7 without emargination at apex.
Legs: Without apparent modification. Genitalia: Aedeagus as illustrated (Figs. 26A, C-D)(393 examined).

Variation. - Color varies from brown to black. There is also some variation in density of
pronotal punctation, but no distinct geographical trends were noted. I have studied the
aedeagus of more than 390 males and have found that there are three rather distinct forms,
which I refer to as aedeagal morphs “A”, “B” and “C” (Figs. 26A, C-D). Aedeagal morph
“A”, which is the morph of the holotype, has a very wide distribution (Fig. 27A) ranging from
Los Angeles County, California northward through the Pacific coast states to British
Columbia, then southward in the Rocky Mountains to Colorado, with a few localities in
Nevada connecting the California and Rocky Mountain components. Aedeagal morph “B” is
known only from the Pacific coast states and British Columbia, apparently absent from the
Rocky Mountains in the United States (Fig. 27B). Aedeagal morph “C” (Fig. 27C) has a very
restricted distribution, being found only in the inland mountains of northern California. I have
seen a total of 89 males of the “B” morph and 26 males of the “C” morph. The localities of
these latter two morphs are entered in the appendix, separately from the “A” morph localities

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88

Perkins

(which are designated paratypes). I am not totally convinced that one and not two or possibly
three species are truly represented here. However, the genitalia are quite similar and could very
well represent three stages in a morphocline. I have therefore decided to treat them as forms of
a single species and hope that pointing out these differences will stimulate additional research
into this problem. A total of 848 specimens of this species were studied (see appendix).

Natural History. - The vast majority of locality descriptors include the terms “stream” or
“creek”, indicating that H. pacifica is primarily a lotic species. Unusual citations include
“pools in drying streambed”, “streambed by sifting”, “ex waterlogged limb in stream”, “bog”,
“pools, small stream in Darlingtonia bog”, and “moss”.

Distribution. - (Figs. 27A-C). Western North America.

Etymology. - Latin pacifica , in reference to geographical distribution.

10. Hydraena calif ornica new species
(Figs. 23D, 28C, 165A)

Type-locality. - Mill Valley, Marin County, California.

Type-specimens. - The holotype male is deposited in CAS. This specimen was collected by
Hugh B. Leech, April 25, 1957. The allotype, which is also deposited in CAS, was collected at
Redwood Park, Humboldt County, California by J. O. Martin in 1918. Paratypes (14) are
listed in the appendix.

Diagnosis. - Aedeagal form plus ochraceous legs and lateral areas of the pronotum serve as
diagnostic features for H. californica .

Description. — Form: Elongate-oval. Size: Holotype 1.76 mm long, 0.78 mm wide. Color: Head with dorsal surface
brown; labrum brown; maxillary palpi testaceous; antennae testaceous. Pronotum with explanate sides ochraceous,
remainder brown. Elytra brown except testaceous explanate margin. Ventral surface brown except legs, elytral epipleura
and inflexed margin of pronotum, ochraceous. Head: Length 0.24 mm. Width 0.42 mm. Frons punctation lightly
impressed, punctures separated by 0.50 puncture diameter; microreticulation both in punctures and on interstices, very
lightly impressed on latter; surface dull. Frontoclypeal suture arcuate to rear. Clypeus microreticulate. Labroclypeal
suture straight across middle when viewed from above. Labrum bilobed, microreticulate, each lobe asymmetrical arc;
median emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.30/0.1 0/0. 22;palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not expecially expanded; palpomere 4 with lateral surface weakly arcuate, median surface more
markedly arcuate, palpomere 4 widest near midlength. Mentum wider than long, surface moderately shining,
microreticulate. Submentum microreticulate as mentum. Genae shining, microreticulate, lateral area of each gena with
well developed foveola; posterior ridge well developed. Postgena microreticulate. Last five antennomeres pubescent. Eyes
0.17 interocular distance in width. Thorax: Pronotum length at midline 0.40 mm; maximum width (at approximately
midlength) 0.58 mm; sides margined, denticulate; sides moderately produced at middle, slightly sinuate and slightly
convergent to anterior angle, sinuate and convergent to posterior; anterior border 0.46 mm wide, straight and nearly
perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.48 mm wide, slightly
arcuate to rear. Posterointernal foveolae moderately developed; punctures in foveola closer together than those on disc.
Antero- and posteroexternal foveolae confluent, sides of pronotum explanate. Area between external foveolae slightly
elevated. Transverse foveola slightly developed, punctures separated by thin walls. Disc dull, punctures moderately small,
separated by thin walls; most punctures without distinctive seta extended above cuticle in dry specimens. Scintilla absent.
Prosternum carinate, carina not produced anteriorly as very short spine; coxae separated by thin, median carina; carina
sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median
carina extended to base of intercoxal process; intercoxal process relatively narrow, sides tapered, apex subacute, width near
apex 0.33 distance between internal and median carinae. Metasternum with plaques well developed, straight, convergent
moderately from posterior to anterior; plaques 0.50 length of metasternum in midline; width of each plaque subequal to
width of intercoxal process at its midlength; plaques separated posteriorly by approximately twice plaque width; plaques
separated anteriorly by plaque width; plaques flat in cross section. Elytra: Length 1.16 mm. Maximum width (at
midlength) 0.78 mm. Surface moderately shining, disc with 10 rows of punctures between suture and humeral callus, rows
and puncture shape quite irregular; intervals not elevated, reduced to narrow, irregular walls, as are interstices between
adjacent punctures of row; each puncture with seta. Explanate margin well developed, ended near apices, with extremely
fine, well separated serrations along entire margin. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect,

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elytral margin elevated slightly obliquely toward suture, in form of slight angle with opposite elytron. Abdomen:
Intercoxal segment concave. Glabrous segments at apex slightly produced. Segment 7 slightly emarginate at apex.
Legs: Without apparent modification. Genitalia: Aedeagus as illustrated (Fig. 28C)(12 examined).

Figs. 26A - D, Aedeagi of Hydraena species. (A) H. pacifica, holotype. (B) H. atlantica , holotype. (C) H. pacifica, morph
“B”, Marin County, California. (D) H. pacifica , morph “C”, Shasta County, California.

Natural History. - Two locality citations include the term “creek”, the remaining citations
give no information about habitat.

Distribution. - (Figs. 23D, 165A). Restricted to the coastal ranges of northern California
from Humboldt County south to Santa Cruz County.

Etymology. - H. californica , in reference to the geographical distribution.

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Figs. 27A - F, Geographical distributions of Hydraena species. (A) H. pacifica, morph “A”. (B) H. pacifica , morph “B”.
(C) H. pacifica , morph “C”. (D) H. arenicola. (E) H. petila. (F) H. nigra.

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11. Hydraena petila new species
(Figs. 27E,28D,165A)

Type-locality. - Dead Mule spring, 3 km by road N. of Paskenta-Covelo road, 1570 meters,
Tehama County, California.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. Hugh B. Leech collected these specimens August 29, 1972. Paratypes (96) are listed in
the appendix.

Diagnosis. - Aedeagal form is the only totally reliable diagnostic feature for males of this
species.

Description. — Form: Elongate-oval. Size: Holotype 1.90 mm long, 0.80 mm wide. Color: Dorsal surface black.
Maxillary palpi testaceous; antennae testaceous. Ventral surface dark brown except legs, elytral epipleura and inflexed
margin of pronotum, brown. Head: Length 0.24 mm. Width 0.46 mm. Frons punctation coarse, punctures separated by
0.33 puncture diameter or less, microreticulation present both in punctures and on interstices; surface dull. Frontoclypeal
suture arcuate to rear. Clypeus microreticulate except at anterior border. Labroclypeal suture straight across middle when
viewed from above. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.32/0.12/0.22; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not expecially
expanded; palpomere 4 with lateral and medial surfaces arcuate; widest slightly past midlength. Mentum wider than long,
surface moderately shining, microreticulate. Submentum microreticulation similar to mentum. Genae dull,
microreticulate, lateral area of each gena with well developed foveola; posterior ridge well developed. Postgena with
punctation slightly smaller than that of submentum. Last five antennomeres pubescent. Eyes 0.20 interocular distance in
width. Thorax: Pronotum length at midline 0.40 mm; maximum width (at approximately midlength) 0.60 mm; sides
margined, denticulate; sides moderately produced at middle, slightly sinuate and slightly convergent to anterior angle,
sinuate and convergent to posterior; anterior border 0.48 mm wide, straight and nearly perpendicular to midline in lateral
0.25, moderately arcuate to rear in middle 0.50; posterior border 0.52 mm wide, slightly arcuate to rear. Posterointernal
foveolae well developed; punctures in foveola closer together than those on disc. Anteroexternal and posteroexternal
foveolae confluent; sides of pronotum explanate. Transverse foveola moderately developed, punctures separated by thin
walls. Disc dull, punctures separated by 0.33 puncture diameter to thin walls; microreticulation in punctures, absent from
interstices; each puncture with distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum
carinate, carina not produced anteriorly as very short spine; coxae separated by thin, median carina; carina sinuate line in
lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median carina not
extended to base of intercoxal process; intercoxal process relatively narrow, sides tapered, apex subacute, width near apex
0.33 distance between internal and median carinae. Metasternum with low ridge posterior to intercoxal process; plaques
well developed, straight, convergent moderately from posterior to anterior; plaques 0.57 length of metasternum in midline;
width of each plaque 0.66 width of intercoxal process at its midlength; plaques separated posteriorly by approximately
twice plaque width; plaques separated anteriorly by plaque width; plaques flat in cross section. Elytra: Length 1.28 mm.
Maximum width (at midlength) 0.80 mm. Surface dull, disc with 10 rows of punctures between suture and humeral callus,
rows quite regular; most punctures rectangular; intervals elevated, width approximately equal to 0.50 puncture diameter,
as are interstices between adjacent punctures of row; each puncture with seta. Explanate margin moderately developed,
ended near apices, with serrations along entire margin, those near anterior angles and apices larger than remainder.
Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in
form of angle with opposite elytron. Abdomen: Intercoxal segment concave. Glabrous segments at apex weakly produced.
Segment 7 without emargination at apex. Legs: Without apparent modification. Genitalia: Aedeagus as illustrated
(Fig. 28D)(52 examined).

Natural History. - Nearly all of the locality records indicate “creek” or “stream”. Unusual
habitat descriptions include “moss-edged rock pools in running stream, open area”, and “clean
water pools in gravel and stones of otherwise dry and shaded creek bed”.

Distribution. - (Figs. 27E,165A). Coastal mountain ranges of central and northern
California plus one locality at Vancouver, British Columbia.

Etymology. - Latin, petila (slender). This name refers to the slender aedeagus.

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12. Hydraena mignymixys new species
(Figs. 23E,28B,165A)

Type-locality. - Dried bed of Cottage City creek, Lucerne, Lake County, California.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. Paratypes (11) from the same locality are deposited in CAS, USNM and PDP. Hugh
B. Leech collected these specimens July 30, 1955.

Diagnosis. - Small, narrow body (1.56 x 0.60 mm) and non-serial arrangement of punctures
on the elytral disc serve to distinguish adults of this species from other members of the circulata
Group in western North America. H. appalachicola adults from eastern North America also
have some non-serial elytral punctures on the disc but differ in body form, color and sculpture.

Description. — Form: Elongate. Size: Holotype 1.56 mm long, 0.60 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous except for dark brown
macula on disc. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum,
brown. Head: Length 0.20 mm. Width 0.38 mm. Frons punctation coarse, punctures confluent; microreticulation
prominent within punctures; surface dull. Frontoclypeal suture slightly arcuate to rear. Clypeus microreticulate except at
anterior border, very smooth. Labroclypeal suture straight across middle in dorsal aspect. Labrum bilobed,
microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary
palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:0.26/0. 10/0.20; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly
straight in basal 0.33, arcuate in apical 0.66, median surface arcuate; palpomere 4 widest near midlength. Mentum wider
than long, surface moderately shining, microreticulate. Submentum with punctation similar to mentum. Genae dull,
microreticulate, lateral area of each gena with well developed foveola; posterior ridge well developed. Postgena with
microreticulation smaller than that of submentum. Last five antennomeres pubescent. Eyes slightly less than 0.17
interocular distance in width. Thorax: Pronotum length at midline 0.34 mm; maximum width (at approximately
midlength) 0.44 mm; sides margined, denticulate; sides moderately produced at middle, slightly arcuate and slightly
convergent to anterior angle, sinuate and convergent to posterior; anterior border 0.38 mm wide, straight and nearly
perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.38 mm wide, slightly
arcuate to rear. Posterointernal foveolae moderately developed; punctures in foveola confluent. Posteroexternal foveola
weakly developed, lnterfoveolar depression slightly developed. Area between external foveolae moderately elevated.
Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33
width of anterior region of pronotum. Transverse foveola weakly developed. Disc dull, punctures confluent; interstices in
form of irregular patterns; microreticulation quite evident within punctures, but absent from interstices; most large
punctures with distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina not
produced anteriorly as very short spine; coxae separated by thin, median carina sinuate line in lateral aspect. Mesosternum
with internal and external carinae divergent from anterior to posterior; median carina not extended to base of intercoxal
process; intercoxal process relatively narrow, sides tapered, apex round, width near apex 0.33 distance between internal
and median carinae. Metasternum with plaques well developed, straight, parallel; plaques 0.50 length of metasternum in
midline; width of each plaque subequal to width of intercoxal process at its midlength; plaques separated by plaque width;
plaques sloped slightly toward midline, each plaque very slightly concave. Elytra: Length 0.98 mm. Maximum width (at
midlength) 0.60 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus at extreme
anterior and in posterior 0.50, punctures in middle more deeply impressed and random; intervals in posterior 0.50 slightly
elevated, width approximately equal to 0.33 puncture width, interstices between adjacent punctures of row generally
narrower; each puncture with perceptible seta. Explanate margin quite narrow, ended near apices, with serration near
anterior angles and in apical 0.25. Elytral apices, in dorsal aspect, gradually rounded; viewed posteriorly, elytral margin
rises very slightly, obliquely towards suture, in form of very slight angle with opposite elytron. Abdomen: Intercoxal
segment concave. Glabrous segments at apex weakly produced. Segment 7 without emargination at apex. Legs: Without
apparent modification. Genitalia: Aedeagus as illustrated (Fig. 28B)(6 examined).

Distribution. - (Figs. 23E,165A). Known only from the type-locality at Lucerne, Lake
County, California.

Etymology. - Greek, mignymi (mix up, mingle) plus ixys (the small of the back). This
name refers to the non-serial arrangement of some punctures on the elytral disc.

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13. Hydraena quadricurvipes new species
(Figs. 24A-B,25D,165A)

Type-locality. - 2 miles NE Subligna, outside Parker Cave, Chattooga County, Georgia.

Type-specimens. - The holotype male is deposited in CFMNH. This specimen was collected
by S. Peck and A. Fiske June 20, 1967. The allotype, which is also deposited in CFMNH, has
the following data; Alabama, St. Claire Co., 3 miles NE Whitney Junction, outside McGlendon
Cave, June 15, 1967, S. Peck and A. Fiske collectors. Paratypes (7) are listed in the appendix.

Diagnosis. - Adults of this distinctive species are easily recognized by form of the meso- and
metatibiae, which are very markedly arcuate in males and weakly arcuate in females. All other
species in the circulata Group have straight meso- and metatibiae. Both sexes have the elytra
broadly explanate and relative length of the ultimate segment of the maxillary palpus is greater
than that seen in other species, more than twice the length of the penultimate article. H.
quadricurvipes includes the most robust members of the circulata group.

Description. — Form: Moderately ovate, convex. Size: Holotype 1 .90 mm long, 0.90 mm wide. Color: Head with
dorsal surface dark brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum brown except
dark brown macula on disc. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of
pronotum, brown. Head: Length 0.26 mm. Width 0.46 mm. Frons punctation coarse, microreticulate; interstices between
punctures 0.33 puncture diameter or less; microreticulation quite evident in larger punctures, present, but lightly
impressed on interstices; surface dull. Frontoclypeal suture slightly arcuate to rear. Clypeus microreticulate. Labroclypeal
suture straight across middle when viewed from above. Labrum bilobed, microreticulate; each lobe asymmetrical arc;
median emargination ending slightly before midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.26/0.10/0.24; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface slightly arcuate; median surface sinuate;
palpomere 4 widest slightly before midlength. Mentum wider than long, surface moderately dull, microreticulate.
Submentum with microreticulation similar to mentum. Genae dull, with large, irregular punctures; lateral area of each
gena with well developed foveola;posterior ridge well developed. Postgena with microreticulation similar to that of
submentum. Last five antennomeres pubescent. Eyes 0.16 interocular distance in width. Thorax: Pronotum length ai
midline 0.44 mm; maximum width (at approximately midlength) 0.64 mm;sides margined, denticulate; sides moderately
produced at middle, slightly sinuate and very slightly convergent to anterior angle, sinuate and convergent to posterior;
anterior border 0.54 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in
middle 0.50; posterior border 0.54 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal
foveolae well developed. Interfoveolar depression well developed, disc elevated. Area between external foveolae moderately
elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across slightly less
than 0.33 width of anterior region of pronotum. Transverse foveola not developed, punctures in this area somewhat closer
together than punctures on disc. Disc dull, punctures large and deeply impressed, separated by 0.33 puncture diameter or
less; microreticulation well impressed in large punctures, very lightly impressed on interstices; most punctures without
distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina not produced
anteriorly as very short spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum
with internal and external carinae divergent from anterior to posterior; median carina not extended to base of intercoxal
process; intercoxal process relatively narrow, sides tapered, apex acute, width near apex 0.25 distance separating internal
and median carinae. Metasternum with low ridge in midline between anterior region of plaques and intercoxal process;
plaques well developed, medial margins convergent, lateral margins parallel, therefore each plaque wider at anterior than
posterior; plaques 0.50 length of metasternum in midline; greatest width of each plaque 0.33 again larger than width of
intercoxal process at its midlength; plaques separated posteriorly by approximately twice plaque width; plaques separated
anteriorly by less than 0.50 plaque width; plaques flat in cross setion. Elytra: Length 1.28 mm. Maximum width (at
midlength) 0.90 mm. Surface moderately dull, disc with 10 rows of punctures between suture and humeral callus, rows
quite regular; most punctures rectangular; intervals not elevated, width approximately equal to 0.50 puncture width, as are
interstices between adjacent punctures of a row; most punctures without perceptible seta. Explanate margin quite broad,
ended near apices, with serrations along entire margin, those near anterior angles well developed. Elytral apices, in dorsal
aspect, gradually rounded; viewed posteriorly, elytral margin not elevated obliquely toward suture, not in form of angle
with opposite elytron. Abdomen: Intercoxal segment concave. Glabrous segments at apex weakly produced. Segment 7
without apical emargination. Legs: Meso- and metatibiae markedly arcuate; apical 0.33 of each expanded. Genitalia:
Aedeagus as illustrated (Figs. 24A-B)(4 examined).

Variation. - As noted in the diagnosis, the meso- and metatibiae of females are very slightly
arcuate, whereas those of males are markedly so. Males from Indiana have the aedeagus

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slightly different than that seen in the holotype and other southern specimens. I have illustrated
the aedeagus of a specimen from Monroe County, Indiana for comparative purposes
(Fig. 24B). No significant, non-sexual external variation was noted in the nine specimens
studied.

Natural History. - The specimens from Alabama and Georgia were taken at or near the
entrance to caves. The specimen from Marshall County, Alabama has the label notations,
“River Cave” and “floor debris light zone at entrance”. The holotype and one male paratype
from Chattooga County, Georgia are from “outside Parker Cave” while the paratype from St.
Claire County in the same state has the label reading, “outside McGlendon Cave”. The latter
three specimens were taken in berlese samples. One of the examples from Indiana was taken
from a “small stream near Needmore”, according to the label notation of F. N. Young. Label
data of the remaining specimens do not describe habitat. Whether H. quadricurvipes truly has
an affinity for cave entrance habitats, and whether the unusual legs of this species are causually
related to that habitat are questions which require further study to clarify.

Distribution. - (Figs. 25D,165A). Presently known from the states of Indiana, Maryland,
Alabama and Georgia.

Etymology. - Latin, quadri (four) plus curv (bend) plus ipes (foot). Named in reference to
the arcuate meso- and metatibiae.

14. Hydraena yosemitensis new species
(Figs. 23D,28A,165A)

Type-locality. - Yosemite Falls, Mariposa County, California.

Type-specimen. - The holotype male (unique) is deposited in CAS. This specimen was
collected by F. Vaillant, August 28, 1962.

Diagnosis. - Broad body form (1.78 x 0.88 mm) with very transverse pronotum, plus the
short, stout legs and relatively short palpi serve to distinguish adults of H. yosemitensis from
those of other species of the circulata Group.

Description. — Form: Broad. Size: Holotype 1.78 mm long, 0.88 mm wide. Color: Dorsal surface dark brown,
nearly black. Maxillary palpi and antennae brown. Ventral surface dark brown except legs, elytral epipleura and inflexed
margin of pronotum, brown. Head: Length 0.24 mm. Width 0.48 mm. Frons punctation coarse, interstices between
punctures 0.50 puncture diameter of less; microreticulation present in punctures only, absent from interstices; surface dull.
Frontoclypeal suture arcuate to rear. Clypeus microreticulate. Labroclypeal suture straight across middle when viewed
from above. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at approximately
midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.22/0.08/0.14; palpomere 2 bent outward at approximately midlength; apex of palpomere 2 relatively broad; palpomere 4
broad, lateral surface slightly arcuate, medial surface more strongly arcuate, widest near midlength. Mentum wider than
long, surface dull, microreticulate. Submentum microreticulate. Genae dull, microreticulate, lateral area of each gena with
a well developed foveola; posterior ridge well developed. Postgena microreticulate. Last five antennomeres pubescent. Eyes
slightly less than 0.20 interocular distance in width. Thorax: Pronotum length at midline 0.40 mm; maximum width (at
approximately midlength) 0.62 mm; sides margined, denticulate; sides moderately produced at middle, straight and
slightly convergent to anterior angle, sinuate and convergent to posterior; anterior border 0.52 mm wide, straight and
nearly perpendicular to midline in lateral 0.33, slightly arcuate to rear in middle 0.33 posterior border 0.54 mm wide,
slightly arcuate to rear. Posterointernal foveolae moderately developed; punctures in foveola closer together than those on
disc. Posteroexternal foveola strongly developed. Interfoveolar depression weakly developed. Area between external
foveolae moderately elevated. Anteroexternal foveolae well developed, each foveola somewhat cresent shaped, extended
across slightly less than 0.33 width of anterior region of pronotum. Transverse foveola moderately developed, punctures
somewhat closer together than punctures on disc. Disc dull, punctures separated by 0.50 puncture diameter,
microreticulation only in punctures, absent from interstices; each puncture with distinctive seta extended above cuticle in
dry specimens. Scintilla absent, prosternum carinate, carina not produced anteriorly as very short spine; coxae separated
by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae parallel;
median carina not extended to base of intercoxal process; intercoxal process relatively narrow, sides tapered; apex

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petila.

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subacute, width near apex 0.33 distance between internal and median carinae. Metasternum with low ridge posterior to
intercoxal process; plaques well developed, straight, convergent moderately from posterior to anterior; plaques 0.50
length of metasternum in midline; width of each plaque subequal to width of intercoxal process at its midlength; plaques
separated posteriorly by approximately plaque width; plaques separated anteriorly by 0.50 plaque width; plaques flat in
cross section. Elytra: Length 1.20 mm; maximum width (at midlength) 0.88 mm. Surface dull, disc with 10 rows of
punctures between suture and humeral callus, rows quite regular; most punctures irregular in shape, intervals not
elevated, width approximately equal to puncture diameter, as are interstices between adjacent punctures of row; each
puncture with seta. Explanate margin moderately developed, ended near apices, with serrations near anterior angles.
Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin not elevated obliquely toward
suture, not in form of angle with opposite elytron. Abdomen: Intercoxal segment concave. Glabrous segments at apex
weakly produced. Segment 7 without emargination at apex. Legs: Legs relatively short and stout. Genitalia: Aedeagus
as illustrated (Fig. 28A)(1 examined).

Distribution . - (Figs. 23D,165A). Known only from the type-locality at Yosemite Falls,
Yosemite National Park, Mariposa County, California.

Etymology. - Latin yosemitensis, in reference to the geographical distribution.

The pennsylvanica Complex

15. Hydraena pennsylvanica Kiesen wetter
(Figs. 25C,29A,165B)

Hydraena pennsylvanica Kiesenwetter 1849:166 (Neotype male deposited in USNM, here designated; type-locality:

Bryant Road, Emmet County, Michigan). - d’Orchymont, 1923:41.

Despite inquiries at various European museums, I was unable to find the holotype of this
species, and believe that it has been destroyed. To insure taxonomic stability a neotype is herein
designated.

Diagnosis. - This species is most easily confused with H. ancylis and H. angulicollis, two
species with which it is sympatric in the eastern United States. Specimens of H. pennsylvanica
can be distinguished from those of H. ancylis by aedeagal form and the more widely separated
metasternal plaques of the latter. Most specimens of H. pennsylvanica can be distinguished
from most specimens of H. angulicollis by the latter’s dark color, smoother pronotum, smaller

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97

size and non-elevated elytral intervals. However, as discussed in the diagnosis and variation
sections of H. angulicollis, certain specimens can be distinguished only by referral to aedeagal
characteristics.

Description. — Form: Elongate oval. Size: Neotype 1.80 mm long, 0.80 mm wide. Color: Head with dorsal surface
dark brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum dark brown except narrow
testaceous border at anterior and posterior. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and
inflexed margin of pronotum, brown. Head: Length 0.24 mm. Width 0.40 mm. Frons punctation coarse, interstices equal
to 0.50 puncture diameter; interstices shining. Frontoclypeal suture slightly arcuate to rear. Clypeus finely punctulate.
Labroclypeal suture straight when viewed from above. Labrum bilobed; surface punctulate; each lobe symmetrical arc;
median emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.28/0.12/0.20; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral and medial surfaces weakly arcuate, widest near
midlength. Mentum wider than long, surface slightly shining, finely punctulate. Submentum evenly, finely punctulate,
punctures contiguous. Genae weakly shining, with several large pits; lateral area of each gena with well developed foveola;
posterior ridge well developed. Postgena with punctation similar to that of submentum. Last five antennomeres pubescent.
Eyes 0.20 interocular distance in width. Thorax: Pronotum length at midline 0.40 mm; maximum width (at approximately
midlength) 0.56 mm; sides margined, denticulate; sides moderately produced at middle, slightly sinuate and slightly
convergent to anterior angle, sinuate and convergent to posterior; anterior border 0.46 mm wide, straight and nearly
perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.56 mm wide, slightly
arcuate to rear. Posterointernal foveolae very slightly developed; punctures in foveola closer together than those on disc.
Posteroexternalfoveola moderately developed. Area between external foveolae nearly flat. Anteroexternal foveolae well
developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior region of
pronotum. Transverse foveola weakly developed. Disc relatively dull, but with interstices shining, punctures large and
deeply impressed, separated by 0.50 puncture diameter or less; each puncture with distinctive seta extended above cuticle
in dry specimens. Scintilla absent. Prosternum carinate, carina not produced anteriorly as very short spine; coxae separated
by thin, median carina, carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent
from anterior to posterior; median carina continued to base of intercoxal process; intercoxal process relatively narrow, sides
tapered, apex acute, width near apex 0.25 distance between internal and median carinae. Metasternum with plaques well
developed, straight, converging moderately from posterior to anterior; plaques 0.57 length of metasternum in midline;
width of each plaque slightly greater than width of intercoxal process at its midlength; plaques separated posteriorly by
slightly less than plaque width; plaques separated anteriorly by 0.50 plaque width; plaques flat in cross section; shallow
furrow lateral to each plaque. Elytra: Length 1.20 mm. Maximum width (at midlength) 0.80 mm. Surface moderately
shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most punctures rectangular;
intervals very slightly elevated, width approximately equal to 0.50 puncture diameter, interstices between adjacent
punctures of row generally narrower; each puncture with seta. Explanate margin moderately developed, ended near apices,
with serrations near anterior angles and apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect,
elytral margin not elevated obliquely toward suture, not in form of angle with opposite elytron. Abdomen: Intercoxal
segment concave. Glabrous segments at apex weakly produced. Segment 7 extremely weakly emarginate at apex. Legs:
Without apparent modification. Genitalia: Aedeagus as illustrated (Fig. 29A)(252 examined).

Variation. - Most specimens have the pronotal puncture density midway between the more
dense H. ancylis and the less dense H. angulicollis. However, at the rough extreme of its
sculpture cline H. pennsylvanica duplicates the form seen in H. ancylis. Likewise, at the
smooth extreme of the cline it duplicates the rough extreme of H. angulicollis. The aedeagus
characteristic of H. pennsylvanica males does not vary significantly. I have examined 610
specimens (see appendix).

Natural History. - Habitat descriptors include “brook”, “bog”, “sifting moss”, “swamp”,
“leaf litter using a Berlese funnel”, “lake shore litter”, “swamp, sphagnum”, “moss on willow
buttress”, and “Berlese, clumps of moss and grass from swampy area overgrown with willows”.
The repeated occurrence of “bog” and “ sphagnum” in the locality data suggest that this is the
preferred habitat of H. pennsylvanica. detailed study of the natural history of this species is
necessary to confirm this assertion.

Distribution. - (Figs. 25C,165B). Northeastern United States and adjacent Canada west to
Minnesota.

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Figs. 29A - D, Aedeagi of Hydraena species. (A) H. pennsylvanica , neotype. (B) H. ancylis, holotype. (C) H. vandykei.
(D) H. nigra , holotype.

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16. Hydraena ancylis new species
(Figs. 25D,29B,165B)

Type-locality. - Five miles NW Davidsburg, York County, Pennsylvania.

Type-specimens. - The holotype male is deposited in USNM. Paul Spangler and I collected
this specimen, September 3, 1972. The allotype, which is also deposited in USNM, was
collected by Paul Spangler at the same locality, July 7, 1962. Paratypes (21) are listed in the
appendix.

Diagnosis. - Most adults have the pronotum slightly more coarsely punctate and the sides
slightly more angulate than have adults of other eastern species of the circulata Group.
Additionally, the plaques are usually slightly closer together than that seen in the other species
with which H. ancylis is sympatric. Positive identification, however, should only be made after
study of the aedeagus (Fig. 29B).

Description. — Form: Elongate oval. Size: Holotype 1.80 mm long, 0.76 mm wide. Color: Head with dorsal surface
dark brown; labrum dark brown; maxillary palpi brown; antennae testaceous. Pronotum dark brown except for narrow
testaceous border at anterior and posterior. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and
inflexed margin of pronotum, brown. Head: Length 0.24 mm. Width 0.46 mm. Frons punctation coarse, narrow walls
separating punctures; microreticulation in punctures only, absent from interstices; surface dull. Frontoclypeal surface
slightly arcuate to rear. Clypeus microreticulate. Labroclypeal suture straight across middle in dorsal aspect. Labrum
bilobed, microreticulate; each lobe asymmetrical arc; median emargination ended at approximately midlength of labrum.
Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.32/0.12/0.24; palpomere 2 bent
outward at approximately midlength; apices of palpomeres 2 and 3 not especially expanded; apical segment with lateral
and medial surfaces slightly arcuate; apical segment widest near apical 0.33. Mentum wider than long, surface dull, finely
microreticulate. Submentum microreticulation similar to mentum. Genae dull, finely microreticulate; area of each gena
with well developed foveola; posterior ridge well developed. Postgena with microreticulation smaller than that of
submentum. Last five antennomeres pubescent. Eyes slightly greater than 0.25 interocular distance in width. Thorax:
Pronotum length at midline 0,42 mm; maximum width (at approximately midlength) 0.60 mm; sides margined,
denticulate; sides moderately produced at middle, slightly sinuate and slightly convergent to anterior angle, sinuate and
convergent to posterior; anterior border 0.50 mm wide, straight and nearly perpendicular to midline in lateral 0.25,
moderately arcuate to rear in middle 0.50; posterior border 0.52 mm wide, slightly arcuate to rear. Posterointernal foveolae
slightly developed; punctures in foveola closer together than those on disc. Posteroexternal foveola moderately developed.
Interfoveolar depression slightly developed. Area between external foveolae nearly flat. Anteroexternal foveolae well
developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior region of
pronotum. Transverse foveola very slightly developed, with punctures somewhat closer together than punctures on disc.
Disc dull, punctures separated by thin walls; each puncture with distinctive seta extended above cuticle in dry specimens.
Scintilla absent. Prosternum carinate, carina not produced anteriorly as very short spine; coxae separated by thin, median
carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to
posterior; median carina not extended to base of intercoxal process; intercoxal process relatively narrow, sides tapered,
apex subacute, width near apex 0.50 distance between internal and median carinae. Metasternum with plaques well
developed, lateral margins parallel, medial margins weakly arcuate away from midline; plaques 0.50 length of
metasternum in midline; width of each plaque subequal to width of intercoxal process at its midlength; plaques separated
anteriorly and posteriorly by approximately plaque width; plaques flat in cross section. Elptra: Length 1.24 mm.
Maximum width (at midlength) 0.76 mm. Surface dull, disc with 10 rows of punctures between suture and humeral callus,
rows quite regular; most punctures rectangular, intervals elevated, width approximately equal to 0.33 puncture width, as
are interstices between adjacent punctures of a row; surface of each interval uneven, reflections interrupted; each puncture
with seta. Explanate margin moderately developed, ended near apices, with serrations along entire margin, those in
anterior and posterior 0.33 quite prominent. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral
margin not elevated obliquely toward suture, not in form of angle with opposite elytron. Abdomen: Intercoxal segment
concave. Glabrous segments at apex slightly produced. Segment 7 without emargination at apex. Legs: Without apparent
modification. Genitalia: Aedeagus as illustrated (Fig. 29B)(13 examined).

Variation. - Some specimens have a rather distinctive ochraceous coloration of the
pronotum.

Natural History. - The stream at the type-locality was very small, probably spring-fed. The
margin, where the beetles were found, was composed mostly of gravel and had slightly elevated,
grassy banks. Other locality data indicate “pond” and “ Sphagnum ” habitats.

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Distribution. - (Figs. 25D,165B). From Maryland west to Indiana and Missouri, then south
to Louisiana and southeasternmost Texas.

Etymology. - Greek ankylis (hook). This name refers to the hook-shaped apex of the
aedeagus.

Remarks. - The Texas locality of H. ancylis represents the southernmost known point of
distribution for the circulata Group.

17. Hydraena vandykei d’Orchymont
(Figs. 23C,29C,165B)

Hydraena vandykei d’Orchymont 1923:42 (holotype male in 1SNB; type-locality: Rossvail, Marin County, California). -

Leech and Chandler, 1956:333.

Diagnosis. - Distinguished from other members of the circulata Group, except H. sierra , by
the generally lighter color, slightly smaller pronotum with the lateral depressed areas more
explanate and the sides slightly more incised at the rear, and, especially, the rather long, dense
pubescence lateral to each metasternal plaque. The aedeagus is distinctive and must be studied
to differentiate males of H. vandykei and H. sierra.

Description. — Form: Elongate. Size: Holotype 1.88 mm long, 0.76 mm wide. Color: Dorsal surface brown.
Maxillary palpi and antennae testaceous. Ventral surface dark brown except legs, elytral epipleurae and inflexed margin of
pronotum, brown. Head: Length 0.24 mm. Width 0.42 mm. Frons dull, punctation coarse, some punctures confluent,
microreticulation most evident near eyes and in punctures. Frontoclypeal suture arcuate to posterior. Clypeus
microreticulate. Labroclypeal suture straight in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical
arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively;0.28/0. 12/0.24; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly straight in basal 0.33, arcuate in
apical 0.66, median surface arcuate; apical segment widest near apical 0.33. Mentum wider than long, surface moderately
shining, finely microreticulate. Submentum microreticulate. Genae moderately shining, microreticulate, lateral area of
each gena with well developed foveola; posterior ridge well developed. Postgena microreticulate. Last five
antennomeres pubescent. Eyes 0.17 interocular distance in width. Thorax: Pronotum length at midline 0.40 mm;
maximum width (at approximately midlength) 0.54 mm; sides margined, denticulate; sides well produced at middle,
slightly sinuate and slightly convergent to anterior angle, strongly sinuate and convergent to posterior; anterior border
0.44 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50;
posterior border 0.44 mm wide, slightly arcuate to rear. Posterointernal foveolae well developed; anterior region of each
foveola nearly confluent with interfoveolar depression; punctures in foveola confluent. Antero- and posteroexternal
foveolae confluent; side of pronotum explanate. Transversal foveola well developed, with some punctures confluent. Disc
dull, punctures microreticulate, large, separated by thin walls, most punctures with seta extended above cuticle in dry
specimens. Scintilla absent. Prosternum carinate, carina not produced anteriorly as very short spine; coxae separated by
median carina slightly wider than norm; carina sinuate line in lateral aspect. Mesosternum with internal and external
carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process
relatively broad, sides tapered; apex round, width near apex 0.66 distance between internal and median carinae.
Metasternum with plaques well developed, weakly arcuate in posterior 0.50, convergent from posterior to anterior; plaques
0.57 length of metasternum in midline; width of each plaque 0.33 width of intercoxal process at midlength; plaques
separated posteriorly by approximately three times plaque width; plaques separated anteriorly by plaque width; plaques
round in cross section; area lateral to each plaque with relatively dense and long pubescence which overlaps lateral margin
of each plaque slightly. Elytra: Length 1.24 mm, maximum width (at midlength) 0.76 mm. Surface dull, disc with 10 rows
of punctures between suture and humeral callus, rows quite regular; most punctures rectangular; intervals not elevated,
width approximately equal to 0.33 puncture diameter, as are interstices between adjacent punctures of a row; each
puncture with seta. Explanate margin moderately developed, ended near apices, with extremely fine, well separated
serrations along entire margin; serrations somewhat closer near apices. Elytral apices, in dorsal aspect, gradually rounded;
in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen:
Intercoxal segment concave. Glabrous segments at apex very weakly produced. Segment 7 without emargination at apex.
Legs: Without apparent modification. Genitalia: Aedeagus as illustrated (Fig. 29C)(176 examined).

Natural History. - Most locality records cite “stream” or “creek” as habitat. This species is
primarily a psammophilous lotic form; for a detailed discussion of the microhabitat preferences
of H. vandykei and its habitat associates, refer to Perkins (1976)(7/. vandykei and H. circulata

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101

are discussed in that paper under the designation “ Hydraena sp.”). Unusual habitat descriptors
seen during this study include the following, all due to the careful observation of Hugh B.
Leech: “foul pool, dried bed of creek”, “roadside seepage”, “clear water pools in gravel and
stones of otherwise dry and shaded creekbed”, and “moss-edged rock pools in running stream,
open area”.

Distribution. - (Figs. 23C,165B). Coastal mountain ranges of California. One locality is
known from Vancouver, British Columbia, but no specimens are yet known from the
intervening states of Washington and Oregon. A total of 378 specimens were examined (see
appendix).

Remarks. - The aedeagus of the holotype is distorted due to being mounted on a microslide
by a previous worker. I have therefore used another specimen to prepare the illustration.

Figs. 30A - B, Aedeagi of Hydraena sierra. (A) holotype (B) variant from Portland, Oregon.

18. Hydraena sierra new species
(Figs. 23F,30A,B,165B)

Type-locality. - North Fork San Joaquin River, at Sheep Crossing, 6000 feet, Madera
County, California.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. Hugh B. Leech collected these specimens, August 22, 1971. Paratypes (16) are listed
in the appendix.

Diagnosis. - Adults of H. sierra are distinguished from all members of the circulata Group,
except H. vandykei, by the relatively long and dense hydrofuge pubescence lateral to each
metasternal plaque. Aedeagi must be studied to differentiate males of H. sierra and H.
vandykei.

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Perkins

Description. — Form: Elongate. Size: Holotype 1.84 mm long, 0.76 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi brown; antennae testaceous. Pronotum dark brown except narrow brown
border. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum, brown.
Head: Length 0.24 mm. Width 0.44 mm. Frons dull, punctation coarse, punctures separated by narrow walls;
microreticulation in punctures, absent from interstices. Frontoclypeal suture straight across middle in dorsal aspect.
Labrum bilobed, microreticulate, each lobe asymmetrical arc; median emargination ended at approximately midlength of
labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.30/0.12/0.24;
palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4
with lateral surface nearly straight in basal 0.33, arcuate in apical 0.66, median surface arcuate, apical segment widest
near apical 0.33. Mentum wider than long, surface moderately shining, microreticulate. Submentum microreticulate.
Genae dull, finely microreticulate, lateral area of each gena with a well developed foveola; posterior ridge well developed.
Postgena with microreticulation slightly smaller than that of submentum. Last five antennomeres pubescent. Eyes 0.20
interocular distance in width. Thorax: Pronotum length at midline 0.40 mm; maximum width (at approximately
midlength) 0.54 mm; sides margined, denticulate; sides well produced at middle, slightly sinuate and slightly convergent to
anterior angle, sinuate and convergent to posterior; anterior border 0.46 mm wide, straight and nearly perpendicular to
midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.46 mm. wide, slightly arcuate to rear.
Posterointernal foveolae well developed, anterior region of each foveola nearly confluent with interfoveolar depression;
punctures in foveola confluent. Antero- and posteroexternal foveolae confluent, producing explanate sides of pronotum.
Disc dull, punctation coarse, punctures separated by thin walls; microreticulation in larger punctures, absent from
interstices; most punctures with distinctive seta extended above cuticle in dry specimens. Scintilla absent, prosternum
carinate, carina not produced anteriorly as very short spine; coxae separated by thin, median carina; carina sinuate line in
lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median carina not
extended to base of intercoxal process; intercoxal process relatively broad, sides tapered, apex round, width near apex 0.66
distance between internal and median carinae. Metasternum with plaques well developed, slightly arcuate away from
midline in posterior 0.50, convergent moderately from posterior to anterior; plaques 0.57 length of metasternum in midline;
width of each plaque 0.33 width of intercoxal process at its midlength; plaques separated posteriorly by approximately
three times plaque width; plaques separated anteriorly by twice plaque width; plaques round in cross section; area lateral to
each plaque with relatively dense and long pubescence which overlaps lateral margin of each plaque slightly. Elytra:
Length 1.24 mm. Maximum width (at midlength) 0.76 mm. Surface dull, disc with 10 rows of punctures between suture
and humeral callus, rows quite regular; most punctures rectangular; intervals not elevated, width approximately equal to
0.33 puncture diameter, as are interstices between adjacent punctures of a row; intervals and interstices with uneven
surface, reflections interrupted; punctures with seta. Explanate margin moderately developed, ended near apices, with
serrations near anterior angles and apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect elytral
margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment concave.
Glabrous segments at apex weakly produced. Segment 7 without emargination at apex. Legs: Without apparent
modification. Genitalia: Aedeagus as illustrated (Figs. 30A-B)(9 examined).

Variation. - The specimens from the Sierra Nevada Mountains are quite homogeneous. I
have seen one male from Portland, Oregon which I am tentatively assigning to this species. The
aedeagus of this specimen (Fig. 30B) differs slightly from the aedeagi of the Sierran specimens.
Externally, this specimen is shorter, slightly broader, darker and has the elytral series less
regular. This specimen may represent another species, but such a decision must be deferred
until more material becomes available from Oregon and Washington.

Natural History. - H. sierra , like its putative sister-species H. vandykei, is probably a lotic
psammophile. Its distribution in the Sierra Nevada Mountains and its close relationship to H.
vandykei justifies this supposition; available locality data are not definitive in regard to habitat.

Distribution. - (Figs. 23F,165B). Sierra Nevada Mountains of California. One questionable
specimen known from Portland, Oregon.

Etymology. - Spanish (but seemingly Latin) noun in apposition, sierra , in reference to the
Sierra Nevada Mountains of California.

The leechi Group

Leechi Group adults are characterized by possession of posterointernal foveolae on the
pronotum (Figs. 31C,48C). In addition, the genae lack a posterior ridge ((Fig. 48E), and the
intercoxal segment of the abdomen is flat and generally with a straight posterior margin

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103

(Fig. 48D).

The aedeagus is extremely varied among males of the leechi Group, variations including
origin of parameres, shape of parameres, shape of main-piece, and shape of terminal mobile
piece, when present.

Externally the group is quite diverse also, variations including shape of the pronotum,
development of a scintilla, development of microsculpture, patterns of elytral punctation, shape
of plaques, distance separating coxae, and various leg modifications (among others).

Geographically the group is very widespread, ranging from northern Argentina to southern
and northeastern United States (Fig. 160).

The leechi Subgroup

Adults included in the leechi Subgroup are relatively large, about 1.50 to 2.05 mm long,
and both sexes have a well developed scintilla (Figs. 31C,E). Males have occipital ridges
(Figs. 31D,32C), above which extends the scintilla, and also have arcuate hind tibiae which are
provided with a prominent brush of hairs in the distal 0.50 (Figs. 32D-G). Infrequently the
hind tibiae are expanded in addition to having the brush of hairs. Similarity of the basic
aedeagal form (Figs. 33A-D), which is broad in both views and has flat, lobate parameres,
provides further corroboration for the monophyly here proposed.

Individuals of this group are known from the mountains of the southwestern United States
south through the ranges of the Sierra Madre Occidental to the mountains of Oaxaca, Mexico.
Seven species are currently included in the leechi Subgroup.

19. Hydraena leechi new species
(Figs. 33A,34A, 166)

Type-locality. - Oak Creek Canyon, Midgley Bridge, Coconino County, Arizona.

Type-specimens. - The holotype male and allotype with same data are deposited in CAS.
These specimens were collected by Hugh B. Leech, August 25, 1952. Paratypes (180) are listed
in the appendix.

Diagnosis. - Specimens of H. leechi from the eastern part of its range (Fig. 34A) are easily
distinguished, being the only Hydraena with posterointernal foveolae, a large scintilla, and
males with a brush of hairs on the metatibiae. In Arizona, H. leechi is readily distinguished
from H. bituberculata and H. arizonica, both of which have posterointernal foveolae and a
large scintilla, by the form of the plaques, which are absent or reduced to small ovals in H.
leechi , tuberculate laterally in H. bituberculata (Figs. 31H,35B), and carinate in H. arizonica
(Fig. 35A). Additionally, the metatibiae of H. arizonica males are expanded in the region of
the brush of hairs (Figs. 32D,G); males of H. leechi have the metatibiae gradually enlarged
from base to apex (Figs. 32E-F). To reliably differentiate males of H. leechi from those of H.
scopula , the aedeagi must be removed and studied. H. scopula, however, is known only from
Jalisco, Mexico, which is far south of the known southwestern distributional limit of H. leechi.

Description. — Form: Elongate-oval. Size: Holotype 1.80 mm long, 0.76 mm wide. Color: Head with dorsal surface
dark brown; labrum dark brown; maxillary palpi brown; antennae brown. Pronotum dark brown except anterior and
posterior borders slightly lighter. Elytra brown, near color of anterior and posterior borders of pronotum. Ventral surface
dark brown. Head: Length 0.24 mm. Width 0.44 mm. Frons coarsely punctured, interstices approximately 0.50 puncture
diameter; interstices shining; posterior margin emarginate in midline to receive scintilla. Frontoclypeal suture straight.

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Figs. 31 A - H, Hydraena bituberculata. (A) head of <3, dorsal aspect. (B) dorsal habitus. (C) pronotum of <3. (D) occipital
ridges of <3. (E) pronotum of 9. (F) head of 9, dorsal aspect. (G) pronotal scintilla, anterior view. (H) metasternum, oblique
view.

Western Hemisphere Hydraenidae

105

Figs. 32A - G, Hydraena arizonica and H. bituberculata. (A) H. arizonica , dorsum of head, <5. (B) H. arizonica, 3
pronotum. (C) H. arizonica , occipital ridges of <3. (D) H. arizonica, hind leg of 3. (E) H. bituberculata, hind leg of 3. (F)
H. bituberculata, hind tibia of 3. (G) H. arizonica, hind tibia of 3.

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Clypeus microreticulate. Labroclypeal suture nearly straight across middle in dorsal aspect. Labrum bilobed,
microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of labrum.
Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.32/0.16/0.20; palpomere 2 bent
outward at approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral
surface arcuate in basal 0.33, slightly expanded at apical 0.66, median surface sinuate; apical segment widest at
midlength. Mentum wider than long, surface moderately shining, finely punctulate. Submentum microreticulate. Genae
shining; lateral area of each gena with well developed foveola; posterior ridge very slightly developed. Postgena with
microreticulation slightly larger than that of submentum. Antennae with last 5 segments pubescent. Eyes slightly less
than 0.20 interocular distance in width. Thorax: Pronotum length at midline 0.44 mm; maximum width (slightly before
midlength) 0.56 mm; sides margined, denticulate; sides moderately produced at middle, slightly arcuate and convergent
to anterior angles, very slightly sinuate and moderately convergent to posterior; anterior border 0.46 mm wide, straight
and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.50 mm
wide, slightly arcuate to rear. Posterointernal foveolae moderately developed; punctures in foveola similar to those on
disc. Posteroexternal foveola well developed. Interfoveolar depression well defined, discal area elevated. Area between
external foveolae moderately elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped,
extends across slightly less than 0.33 width of anterior region of pronotum. Transverse foveola slightly developed, with
punctures somewhat closer together than punctures on disc. Disc moderately shining, punctures relatively large and
deeply impressed, separated by thin ridges near anterior and posterior borders, by 0.50 puncture diameter in middle;
punctures with distinctive setae extended above cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with
arcuate anterior and posterior margins. Prosternum carinate, carina produced anteriorly as very short spine; coxae
separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae
divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively
narrow, sides parallel, apex rounded, width 0.33 distance between internal and median carinae. Metasternum without
plaques. Elytra: Length 1.20 mm. Maximum width (at midlength) 0.76 mm. Surface shining, disc with 10 rows of
punctures between suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width
approximately equal to 0.50 puncture diameter, interstices between adjacent punctures of row generally narrower;
punctures each with seta. Explanate margin quite narrow, with extremely fine, well separated serrations near anterior
angles and apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated
obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long,
posterior margin arcuate. Glabrous segments at apex moderately produced, length subequal to that of metasternum in
midline. Apical segment slightly emarginate at apex. Legs: Profemur with small tubercle on inner surface near basal
0.33. Protibia very slightly arcuate, prominent spine on inner surface at apical 0.33. Metafemur broad, lateral surface
markedly arcuate, median surface sinuate. Metatibiae gradually enlarged from base to apex; arcuate in basal 0.50; with
prominent brush of hairs at apical 0.33. Genitalia: Aedeagus as illustrated (Fig. 33A)(92 examined).

Variation. - No significant variation was noted in the 180 specimens studied.

Natural History. - The scant habitat data available include the notations, “in moss and
grass roots along stream”, “along creek edge”, “spring”, and “pools, bed below Yank’s Spring”.

Distribution. - (Figs. 34A,166). Southeastern Arizona south to northwestern Mexico and
east to southern Oklahoma.

Etymology. - It is with great pleasure that I dedicate this species to Hugh B. Leech, in
recognition of his many contributions to the study of aquatic beetles in general, and to this
study in particular.

20. Hydraena breedlovei new species
(Figs. 33B, 166)

Type-locality. - Two miles E. of Durango-Sinaloa boundary on highway MEX. 40, 7000
feet, Durango, Mexico.

Type-specimens. - The holotype male and allotype with same data are deposited in CAS.
These specimens were collected by D.E. Breedlove and J.F. Copp on December 30, 1962.
Paratypes (34) are listed in the appendix.

Diagnosis. - Small size (1.48 mm long), strongly arcuate metatibiae which are provided
with a brush of hairs in males, and moderately broad form serve to characterize this species.
Plaques are thin arcuate lines, barely distinguishable, not shiny and therefore not contrasting

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with remainder of metasternum; they are, however, very slightly elevated in males.

Figs. 33A - D, Aedeagi of Hydraena holotypes. (A) H. leechi. (B) H. breedlovei. (C) H. arizonica. (D) H. bituberculata.

Description. — Form: Subovate. Size: Holotype 1.48 mm long, 0.64 mm wide. Color: Head with dorsal surface
dark brown; labrum dark brown; maxillary palpi brown; antennae brown. Pronotum with disc dark brown, lateral areas
lighter. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum, brown.
Head: Length 0.20 mm. Width 0.40 mm. Frons coarsely punctured, interstices less than puncture diameter; interstices
shining; posterior margin emarginate in midline to receive scintilla. Frontoclypeal suture straight. Clypeus microreticulate.

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Labroclypeal suture nearly straight across in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc;
median emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively; 0.24/0.10/0.16; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly straight; median surface arcuate;
apical segment widest at midlength. Mentum wider than long, surface moderately shining, microreticulate. Submentum
microreticulate. Genae shining; lateral area of each gena with well developed foveola; posterior ridge imperceptible.
Postgena with punctation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly less
than 0.25 interocular distance in width. Thorax: Pronotum length at midline 0.40 mm; maximum width (slightly before
midlength) 0.54 mm; sides margined, denticulate; sides moderately produced at middle, slightly arcuate and moderately
convergent to anterior angle, very slightly sinuate and moderately convergent to posterior; anterior border 0.42 mm
wide, straight and nearly perpendicular to midline in lateral 0.25; slightly arcuate to rear in middle 0.50; posterior
border 0.46 mm wide, slightly arcuate to rear. Posterointernal foveolae slightly developed; punctures in foveola similar
to those on disc. Posteroexternal foveola well developed. Interfoveolar depression relatively shallow. Area between
external foveolae moderately elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped,
occupying slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not developed, punctures in
this area somewhat closer together than punctures on disc. Disc slightly shining, punctures coarse, separated by thin
ridges near anterior and posterior borders, and 0.50 puncture diameter or less in middle; punctures with distinctive setae
extended above cuticle in dry specimens. Larger interstices with minute reflections, cuticle with appearance of tiny
reflecting surfaces within. Scintilla distinct, flat, impuntate shelf with arcuate anterior and posterior margins.
Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin, median carina; carina
sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior;
median carina extended to base of intercoxal process; intercoxal process relatively narrow, sides nearly parallel, apex
blunt, width at apex 0.33 distance separating internal and median carinae. Metasternum with plaques weakly developed,
arcuate, convergent rather markedly from posterior to anterior; plaques nearly 0.50 length of metasternum in midline;
each plaque thin, moderately elevated ridge. Elytra: Length 1.00 mm. Maximum width (at midlength) 0.64 mm.
Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most punctures
round; intervals not elevated, width approximately 0.50 puncture diameter, interstices between adjacent punctures of
row generally narrower; punctures each with seta. Explanate margin quite narrow, ended near posterior 0.17, with
extremely fine, well separated serrations near anterior angles and apices. Elytral apices, in dorsal aspect, gradually
rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite elytron.
Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous segments at apex moderately
produced. Apical segment without emargination at apex. Legs: Profemur with minute tubercle on inner surface near
basal 0.33. Protibia slightly arcuate, prominent spine on inner surface at apical 0.33. Metafemur broad; lateral surface
markedly arcuate; median surface sinuate. Metatibia slightly expanded, with prominent brush of hairs at apical 0.33;
basal 0.50 arcuate. Genitalia: Aedeagus as illustrated (Fig. 33B)( 1 7 examined)

Natural History. - I have collected adults of this species from sand and gravel at the margin
of a stream flowing through a pine forest in the mountains of Durango, Mexico.

Distribution. - (Fig. 166). As presently known, restricted to the mountains of Durango,
Mexico.

Etymology. - It is my pleasure to acknowledge the request of Hugh Leech, who had
recognized this species as undescribed, and to dedicate it to D. E. Breedlove, Chairman of the
Department of Botany, California Academy of Sciences.

21. Hydraena arizonica new species
(Figs. 10J,32A-D,G,33C,34A,35A,166)

Type-locality. - Madera Canyon, 6200 feet, Santa Rita Mountains, Santa Cruz County,
Arizona.

Type-specimens. - The holotype male and allotype with identical data are deposited in
CAS. These specimens were collected by Hugh B. Leech, August 1, 1952. Paratypes (47) are
listed in the appendix.

Diagnosis. - Straight, carinate plaques (Fig. 3 5 A) serve to readily distinguish specimens of
Hydraena arizonica from other species whose adults also possess a well developed scintilla.
Additionally, males have the metatibiae expanded and with a brush of hairs (Figs. 32D,G).

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109

Description. — Form: Elongate. Size: Holotype 1.76 mm long, 0.72 mm wide. Color: Dorsal surface dark brown;
maxillary palpi brown; antennae brown. Ventral surface dark brown except legs brown. Head: Length 0.20 mm. Width
0.40 mm. Frons coarsely punctured, interstices usually less than 0.50 puncture diameter; interstices shining; posterior
margin emarginate in midline to receive scintilla. Labroclypeal suture straight. Clypeus microreticulate. Labroclypeal
suture weakly arcuate when viewed from above. Labrum bilobed, microreticulate, each lobe symmetrical arc; median
emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.24/0.12/0.18; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface arcuate in basal 0.33, slightly expanded at
apical 0.66, median surface sinuate; palpomere 4 widest at midlength. Mentum wider than long, surface moderately
shining, finely punctulate. Submentum microreticulate. Genae shining; lateral area of each gena with well developed
foveola; posterior ridge nearly imperceptible. Postgena with microreticulation slightly larger than that of submentum. Last
five antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width. Thorax: Pronotum length at
midline 0,44 mm; maximum width (slightly before midlength) 0.56 mm; sides margined, denticulate; sides moderately
produced at middle, slightly arcuate and slightly convergent to anterior angle, very slightly sinuate and convergent to
posterior; anterior border 0.46 mm wide, straight and nearly perpendicular to midline in lateral 0.25, slightly arcuate to
rear in middle 0.50; posterior border 0.48 mm wide, slightly arcuate to rear. Posterointernal foveolae well developed;
punctures in foveola similar to those on disc. Posteroexternal foveola well developed. Interfoveolar depression well defined,
discal area elevated. Area between external foveolae moderately elevated. Anteroexternal foveolae well developed, each
foveola somewhat crescent shaped, extended across less than 0.33 width of anterior region of pronotum. Transverse foveola
not developed, punctures in this area somewhat closer together than punctures on disc. Disc slightly shining, punctures
relatively large and deeply impressed, separated by thin ridges near anterior and posterior borders, and 0.50 puncture
diameter or less in middle; punctures with setae extended above cuticle in dry specimens. Larger interstices with minute
reflections, cuticle apparently with tiny reflecting surfaces within. Scintilla distinct, flat, impunctate shelf with arcuate
anterior and posterior margins. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by
thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from
anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively narrow, sides
parallel, apex blunt, width at apex 0.33 distance between internal and median carinae. Metasternum with plaques
moderately developed, straight, convergent very slightly from posterior to anterior; plaques nearly 0.50 length of
metasternum in midline; each plaque thin, moderately elevated ridge. Elytra: Length 1.12 mm. Maximum width (at
midlength) 0.72 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite
regular; most punctures round; intervals not elevated, width approximately equal to 0.50 puncture diameter, as are
interstices between adjacent punctures of a row; punctures each with perceptible seta. Explanate margin quite narrow,,
ended near posterior 0.17, with extremely fine, well separated serrations near anterior angles and apices. Elytral apices, in
dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with
opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous segments at apex
moderately produced. Apical segment without emargination at apex. Legs: Profemur with small tubercle on inner surface
near basal 0.33. Protibia very slightly arcuate, prominent spine on inner surface at apical 0.33. Metafemur broad, lateral
surface markedly arcuate, median surface sinuate. Metatibia expanded and with brush of hairs on inner surface near
apical 0.25, basal 0.50 arcuate. Genitalia: Aedeagus as illustrated (Fig. 33C)(27 examined).

Natural History. - Locality data include the notations “along creek edge” and “ex under
stones in small creek in mountains, 2500 meters”.

Distribution. - (Figs. 34A,166). Known from the mountains of southeastern Arizona and
Durango, Mexico.

Etymology. - Latin, arizonica , in reference to location of the type locality.

22. Hydraena bituberculata new species
(Figs. 31 A-H,32E-F,33D,34B,35B-C,166)

Type-locality. - South Fork Cave Creek, 4.5 miles W. Portal, Cochise County, Arizona.

Type-specimens. - The holotype male is deposited in CAS. This specimen was collected by
Hugh B. Leech, July 30, 1965. The allotype, also deposited in CAS, was collected by P. H.
Arnaud, Jr. at the Southwest Research Station in the same county, October 24, 1964.
Paratypes (52) are listed in the appendix.

Diagnosis. - Among those species with a well developed scintilla, H. bituberculata is unique
in possession of a tubercle lateral to each metasternal plaque. (Figs. 31H,35B). Males have a
well developed brush of hairs on the metatibiae.

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Figs. 34A - B, Geographical distributions of Hydraena species. (A) H. leechi • , H. arizonica ★ and H. scopula A •
(B) H. bituberculata • , H. alternata ★ and H. scintilla A •

Figs. 35A - C. (A) Hydraena arizonica, metasternum. (B) H. bituberculata, metasternum. (C) H. bituberculata, 2
abdominal apex.

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111

Description. — Form: Elongate. Size: Holotype 1 .92 mm long, 0.76 mm wide. Color: Head with dorsal surface dark
brown; labrum brown; maxillary palpi brown; antennae testaceous. Pronotum with disc dark brown, lateral areas lighter.
Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum, brown. Head:
Length 0.24 mm. Width 0.44 mm. Frons coarsely punctured, interstices in midline equal to or slightly greater than
puncture diameter; surface shining; posterior margin emarginate in midline to receive scintilla. Frontoclypeal suture
straight. Clypeus finely microreticulate at sides, glabrous in midline. Labroclypeal suture nearly straight across middle in
dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended slightly before
midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.28/0.16/0.20; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface very slightly arcuate 0.33, very slightly expanded at apical 0.66, median very
slightly sinuate; palpomere 4 widest slightly past midlength. Mentum wider than long, surface moderately shining,
microreticulate. Submentum microreticulate. Genae shining; lateral area of each gena with well developed foveola;
posterior ridge slightly developed. Postgena with microreticulation slightly larger than that of submentum. Last five
antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width. Thorax: Pronotum length at midline
0.44 mm; maximum width (at approximately midlength) 0.60 mm; sides margined, denticulate; sides moderately produced
at middle, nearly straight and convergent to anterior angle, very slightly concave and convergent to posterior; anterior
border 0.48 mm wide, straight and nearly perpendicular to midline in lateral 0.20, moderately arcuate to rear in middle
0.60; posterior border 0.52 mm wide, slightly arcuate to rear. Posterointernal foveolae moderately developed; punctures in
foveola similar to those on disc. Posteroexternal foveola well developed. Interfoveolar depression well defined, discal area
elevated. Area between external foveolae moderately elevated. Anteroexternal foveolae well developed, each foveola
somewhat crescent shaped, extended across slightly less than 0.33 width of anterior region of pronotum. Transverse foveola
slightly developed, punctures separated by narrow ridges. Disc shining, punctures relatively large and deeply impressed,
separated by thin ridges near anterior and posterior borders, by puncture diameter in middle; punctures with distinctive
seta extended above cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate hind margin.
Prosternum carinate, carina produced anteriorly into very short spine; coxae separated by thin, median carina; carina
sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent slightly from anterior to posterior;
median carina extended to base of intercoxal process; intercoxal process relatively narrow, increased very slightly in width
from base to apex, apex blunt, width at apex 0.50 distance between internal and median carinae. Metasternum with
prominent tubercle immediately lateral to each plaque; each plaque small oval at posterior 0.25 of metasternum. Elytra:
Length 1.22 mm. Maximum width (at midlength) 0.76 mm. Surface shining, disc with 10 rows of punctures between
suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width approximately equal to
0.50 puncture diameter, interstices generally narrower; punctures each with perceptible seta. Explanate margin quite
narrow, ending near posterior 0.17, with extremely fine, well separated serrations near anterior angles and apices. Elytral
apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of
angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin arcuate. Glabrous
segments at apex moderately produced. Apical segment slightly emarginate at apex. Legs: Profemur with carinate tubercle
on inner surface near basal 0.20; prominent spine on inner surface at apical 0.33. Metafemur broad; lateral surface
markedly arcuate; median surface sinuate. Metatibia slightly expanded with prominent brush of hairs at apical 0.33; basal
0.50 arcuate. Genitalia: Aedeagus as illustrated (Fig. 33D)(33 examined).

Natural History. - Apart from the notation “stream banks”, nothing is known concerning
the habitat of this species.

Distribution. - (Figs. 34B,166). Known only from Cochise County in Arizona and Dona
Ana County in New Mexico.

Etymology. - Latin, bi (two) plus tuberculum (small swelling). Named in reference to the
two metasternal tubercles.

23. Hydraena scintilla new species
(Figs. 34B,36B,D,166)

Type-locality. - One mile N. Ixtlan de Juarez, Oaxaca, Mexico.

Type-specimens. - The holotype male and allotype with same data are deposited in USNM.
These specimens were collected by my wife and I, July 5, 1974. One male paratype (PDP) has
the following data: Intermittent desert stream, 2 miles N. Zimapan, Hidalgo, Mexico, May 21,
1974, M.E. and P.D. Perkins. One paratype of each sex (CAS) has the following data: Mexico,
San Luis Potosi, Ciudad del Maiz, 9-1-1971, J.T. Polhemus.

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Diagnosis. - Large size (1.92-2.02 mm), males with an excavation at the apex of the
protibiae and a cariniform prominence on the inner surface of the profemora, plus aedeagal
form (Figs. 36B,D), serve to distinguish this species from others whose adults also possess a
brush of hairs on the metatibiae (males) and a well developed scintilla (both sexes).

Description. — Form: Elongate. Size: Holotype 1.92 mm long, 0.82 mm wide. Color: Dorsal surface dark brown;
labrum dark brown; maxillary palpi brown except apices dark brown; antennae testaceous. Ventral surface dark brown
except legs, elytral eipipleura and inflexed margin of pronotum brown. Head: Length 0.24 mm. Width 0.44 mm. Frons
coarsely punctured, interstices approximately 0.50 puncture diameter, or less; surface shining; posterior margin
emarginate to receive scintilla. Frontoclypeal suture straight. Clypeus microreticulate laterally, shining in midline.
Labroclypeal suture nearly straight across middle in dorsal aspect. Labrum bilobed, microreticulate, each lobe
symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with following
lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.32/0.16/0.20; palpomere 2 bent outward at approximately
midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 arcuate in basal 0.17, straight in remainder,
median surface sinuate; palpomere 4 widest slightly past midlength. Mentum wider than long, surface moderately shining,
finely punctulate. Submentum microreticulate. Genae shining; lateral area of each gena with well developed foveola;
posterior ridge very slightly developed. Postgena with punctation slightly larger than that of submentum. Last five
antennomeres pubescent. Eyes slightly greater than 0.20 interocular distance in width. Thorax: Pronotum length at
midline 0.48 mm; maximum width (at approximately midlength) 0.62 mm. sides margined, denticulate; sides moderately
produced at middle, slightly arcuate and convergent to anterior angle, very slightly sinuate and moderately convergent to
posterior; anterior border 0.48 mm wide, straight and nearly perpendicular to midline in lateral 0.25, slightly arcuate to
rear in middle 0.50; posterior border 0.54 mm wide, slightly arcuate to rear. Posterointernal foveolae moderately
developed; punctures in foveola similar to those on disc. Posteroexternal foveola well developed. Interfoveolar depression
well defined, discal area elevated. Area between external foveolae well elevated. Anteroexternal foveolae well developed,
each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior region of pronotum.
Transverse foveola slightly developed, with punctures separated by thin walls. Disc moderately shining, punctures
relatively large and deeply impressed, separated by thin walls; punctures with distinctive setae extended above cuticle in
dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate hind margin. Prosternum carinate, carina produced
anteriorly as very short spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum
with internal and external carinae divergent from anterior to posterior; median carina extended to base of intercoxal
process; intercoxal process relatively narrow, sides nearly parallel, apex blunt, width at apex nearly 0.66 distance between
internal and median carinae. Metasternum with plaques weakly developed, of small ovals at posterior 0.20 of
metasternum. Elytra: Length 1.28 mm. Maximum width (at midlength) 0.82 mm. Surface shining, disc with 10 rows of
punctures between suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width
approximately equal to 0.50 puncture diameter, interstices between adjacent punctures of row generally narrower;
punctures each with seta. Explanate margin quite narrow, with extremely fine, well separated serrations near anterior
angles and apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely
toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin
arcuate. Glabrous segments at apex moderately produced. Apical segment slightly emarginate at apex. Legs: Profemur
with cariniform tubercle on inner surface near basal 0.33. Protibia excavate on inner surface at apex; prominent spine on
inner surface at apical 0.33. Metafemur broad, lateral surface markedly arcuate, median surface sinuate. Metatibia
gradually enlarged from base to apex; arcuate in basal 0.50; with prominent brush of hairs near apical 0.33. Genitalia:
Aedeagus as illustrated (Figs. 36B,D)(3 examined).

Variation. - The aedeagus of the male from Hidalgo differs slightly from that of the
holotype (Fig. 36D).

Natural History. - Specimens from the type-locality were removed from leaves which had
become trapped behind water-soaked branches in a moderately large stream (Fig. 195B). Also
taken from the leaves were specimens of H. cuspidicollis. The single male from Hidalgo was
collected from sand and gravel at the margin of a very small, intermittent desert stream;
Ochthebius obscurus adults were also taken at this locality.

Distribution. - (Figs. 34B,166). Known from the states of San Luis Potosi, Hidalgo and
Oaxaca, Mexico.

Etymology. - Latin, scintilla (spark). Named in reference to the well developed pronotal
scintilla.

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113

24. Hydraena canticacollis new species
(Figs. 36C,166)

Type-locality. - Thirteen miles S. Jalpa, Zacatecas, Mexico.

Type-specimen. - The holotype male (unique) is deposited in USNM. My wife and I
collected this specimen, July 16, 1974.

Diagnosis. - Readily distinguished by form of the metasternal plaques which are short but
very markedly carinate. Each plaque is very sharp, nearly as high as long, and has the anterior
extreme gradually tapered to the level of the remainder of the metasternum while the posterior
extreme is extended abruptly above the surrounding area. The pronotum is also distinctive by
virtue of its coarse, widely spaced punctures on the disc; some punctures are separated by twice
their diameters.

Description. — Form: Elongate. Size: Holotype 1.76 mm long, 0.76 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi testaceous except apices brown; antennae testaceous. Pronotum dark brown
except anterior and posterior borders, slightly lighter. Elytra brown. Ventral surface dark brown except legs, elytral
epipeura and inflexed margin of pronotum brown. Head: Length 0.24 mm. Width 0.42 mm. Frons coarsely punctured,
interstices less than puncture diameter; surface moderately shining; posterior margin emarginate in midline to receive
scintilla. Frontoclypeal suture straight. Clypeus microreticulate in lateral areas, shining in midline. Labroclypeal suture
arcuate in dorsal aspect. Labrum bilobed; surface punctulate; each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.32/0.16/0.22; palpomere 2 bent outward at approximately midlength; apex of palpomere 3 relatively expanded;
palpomere 4 with lateral surface arcuate in basal 0.17, straight in remainder, median surface sinuate; apical segment
widest slightly past midlength. Mentum wider than long, surface moderately shining, finely punctulate. Submentum
microreticulate. Genae shining; lateral area of each gena with well developed foveola; posterior ridge nearly imperceptible.
Postgena with microreticulation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly
less than 0.20 interocular distance in width. Thorax: Pronotum length at midline 0.44 mm; maximum width (at
approximately midlength) 0.60 mm; sides margined, denticulate; sides moderately produced at middle, slightly arcuate
and moderately convergent to anterior angles, very slightly sinuate and moderately convergent to posterior; anterior border
0.48 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50;
posterior border 0.52 mm wide, slightly arcuate to rear. Posterointernal foveolae moderately developed; punctures in
foveola closer together than those on disc. Posteroexternal foveola well developed. Interfoveolar depression well defined,
discal area elevated. Area between external foveolae moderately elevated. Anteroexternal foveolae well developed, each
foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior region of pronotum. Transverse
foveola slightly developed, punctures somewhat closer together than punctures on disc. Disc moderately shining, punctures
relatively large and deeply impressed, separated by 0.33 puncture diameter near anterior and posterior borders, punctures
in middle, very unevenly spaced, some interstices thin walls, other equal to twice puncture diameter; punctures without
distinctive setae extended above cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate hind
margin. Prosternum carinate, carina produced anteriorly into a very short spine; coxae separted by thin median carina;
carina a sinuate line when viewed laterally. Mesosternum with internal and external carinae diverging from anterior to
posterior; median continuing to base of intercoxal process; intercoxal process relatively narrow, wider at apex than at base,
apex blunt, width at base 0.33 distance between internal and median carinae. Metasternum with plaques small, carinate,
moderately well elevated, posterior margin truncate. Elytra: Length 1.14 mm. Maximum width (at midlength) 0.76 mm.
Surface moderately shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular;
punctures round; intervals not elevated, width approximately 0.50 puncture diameter, interstices between adjacent
punctures of row approximately 0.25 puncture diameter; punctures each with seta. Explanate margin quite narrow, ended
near posterior 0.20, with extremely fine, well separated serrations along entire margin; serrations somewhat closer near
apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytrai margin extended obliquely toward
suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin
arcuate. Glabrous segments at apex well produced. Apical segment slightly emarginate at apex. Legs: Profemur with small
tubercle on inner surface near basal 0.33. Protibia excavate on inner surface at apex. Metafemur broad, lateral surface
strongly arcuate, median surface sinuate. Metatibia gradually enlarged from base to apex; arcuate in basal 0.50; with
prominent brush of hairs at apical 0.33. Genitalia: Aedeagus as illustrated (Fig. 36C)(1 examined).

Natural History. - This specimen was collected from loose sand at the margin of a stream
outwash area (Fig. 189C). The stream was flowing through a desert habitat. The microhabitat
also contained adults of Limnebius sinuatus.

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Figs. 36A - D, Aedeagi of Hydraena species. (A) H. scopula, holotype. (B) H. scintilla , holotype. (C) H. canticacollis,
holotype. (D) H. scintilla , variant from Hidalgo, Mexico.

Distribution. - (Fig. 166). Known only from type-locality near Jalpa in Zacatecas, Mexico.
Etymology. - Latin, cantica (musical) plus collis (neck). This name refers to the scintilla of
the pronotum and its supposed stridulatory function. It is also an attempt at onomatopoeia.

Western Hemisphere Hydraenidae

115

25. Hydraena scopula new species
(Figs. 34A,36A,166)

Type-locality. - Seven miles S. Mazamitla, Jalisco, Mexico.

Type-specimens. - The holotype male and allotype with same data are deposited in USNM.
My wife and I collected these specimens July 15, 1974; two male paratypes (PDP) were also
taken at that time. Other paratypes include specimens collected by Hugh B. Leech (CAS):
type-locality, December 1, 1948 (2 females); 20 miles W. Jiquilpan, November 30, 1948 (1
male).

Diagnosis. - Among those species whose males have a well developed scintilla and a
metatibial brush of hairs, H. scopula is very similar, externally, to H. leechi. The only reliable
way to differentiate specimens of these two species is by characters of the male genitala
(Fig. 36A).

Description. — Form: Elongate. Size: Holotype 1.76 mm long, 0.74 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi brown; antennae brown. Pronotum with disc dark brown, lateral areas lighter.
Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum brown. Head:
Length 0.24 mm. Width 0.42 mm. Frons coarsely punctured, interstices less than puncture diameter; interstices shining;
posterior margin emarginate in midline to receive scintilla. Frontoclypeal suture straight. Clypeus microreticulate.
Labroclypeal suture nearly straight across middle in dorsal aspect. Labrum bilobed, microreticulate, each lobe
symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with following
lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.28/0.14/0.18; palpomere 2 bent outward at approximately
midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface slightly arcuate in basal
0.25, nearly straight in apical 0.75, median surface sinuate; palpomere 4 widest slightly past midlength. Mentum wider
than long, surface moderately shining, finely punctulate. Submentum microreticulate. Genae shining; lateral area of each
gena with well developed foveola; posterior ridge very slightly developed. Postgena with microreticulation on slightly larger
than that of submentum. Last five antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width.
Thorax: Pronotum length at midline 0.44 mm; maximum width (at approximately midlength) 0.58 mm; sides margined,
denticulate; sides moderately produced at middle, nearly straight and slightly convergent to anterior angle, very slightly
concave and convergent to posterior; anterior border 0.48 mm wide, straight and nearly perpendicular to midline in lateral
0.20, moderately arcuate to rear in middle 0.60, posterior border 0.52 mm wide, slightly arcuate to rear. Posterointernal
foveolae moderately developed; punctures in foveola similar to those on disc. Posteroexternal foveola well developed.
Interfoveolar depression well defined, discal area elevated. Area between external foveolae slightly elevated.
Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across 0.25 width of anterior
region of pronotum. Transverse foveola slightly developed, punctures separated by thin walls. Disc moderately shining,
punctures relatively large and deeply impressed, separated by thin walls near anterior and posterior borders, and by 0.50
puncture diameter in middle; some punctures with distinctive seta extended above cuticle in dry specimens. Scintilla
distinct, flat, impunctate shelf with arcuate anterior and posterior margins. Prosternum carinate, carina produced
anteriorly as very short spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum
with internal and external carinae divergent from anterior to posterior; median carina extended to base of intercoxal
process; intercoxal process relatively narrow, sides nearly parallel, apex blunt, width at apex 0.33 distance between internal
and median carinae. Metasternum with plaques weakly developed, of small ovals at posterior 0.20 of metasternum. Elytra:
Length 1.10 mm. Maximum width (at midlength) 0.74 mm. Surface shining, disc with 10 rows of punctures between
suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width approximately equal to
0.33 puncture diameter, interstices generally narrower; punctures each with perceptible seta. Explanate margin quite
narrow, ending near posterior 0.17 with extremely fine, well separated serrations near anterior angles and apices. Elytral
apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of
angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin arcuate. Glabrous
segments at apex moderately produced. Segment 7 without emargination at apex. Legs: Profemur with small tubercle on
inner surface near basal 0.33. Protibia with prominent spine on inner surface at apical 0.33. Metafemur moderately broad,
lateral surface arcuate, median surface sinuate. Metatibia gradually enlarged from base to apex; arcuate in basal 0.50;
prominent brush of hairs on inner surface at apical 0.33. Genitalia: Aedeagus as illustrated (Fig. 36A)(4 examined).

Natural History. - The type-locality consists of a moderately fast, pine forest stream. The
substratum at the margin of the stream contained a higher percentage of mud than is usually
seen in hydraenid streams. Consocies included H. mazamitla , H. cuspidicollis and H.
crystallina.

Quaest. Ent., 1980, 16 (1,2)

116

Perkins

Distribution. - (Figs. 34A,166). Known only from the state of Jalisco, Mexico.

Etymology. - Latin, scopula (small broom). I refer to the brush of hairs present on the
metatibiae of males.

The alternata Subgroup

This subgroup presently consists of a single unusual species, H. alternata , from the
mountains of Durango, Mexico. The elytra are broadly explanate and have alternate intervals
elevated slightly. The latter feature is unique among Western Hemisphere Hydraena. As in the
lee chi Subgroup, both sexes have a well developed scintilla, and the hind tibiae of males are
arcuate. However, the brush of hairs found on the hind tibiae of leechi Subgroup adults is
replaced by two stiff spines in H. alternata adults. Further, the hind femora of H. alternata
males have a group of prominent, curved hairs on the inner surface; these hairs are not as well
developed in members of the leechi Subgroup.

The aedeagus of H. alternata males (Fig. 37A) is of a different basic form than that of the
leechi Subgroup, providing additional justification for placing it in a separate subgroup.

According to d’Orchymont (1936:18), Kuwert’s (1888) subgenus Taenhydraena has
elevated alternate elytral intervals also. The aedeagal illustration presented by d’Orchymont
(1936:39) for the single species of this subgenus, H. exarata Kiesenwetter, differs greatly from
that of H. alternata. Most likely the elytral charac eristics of these two species have been
independently derived, and are of species-group significance only.

26. Hydraena alternata new species
(Figs. 34B,37A)

Type-locality. - Three miles E. La Ciudad, Durango, Mexico.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. Paul J. Spangler collected these specimens, July 1, 1964. Paratypes (27) are listed
in the appendix.

Diagnosis. - Readily distinguished from all other Western Hemisphere Hydraena by the
broadly explanate elytra which have elevated alternate intervals. The pronotum is coarsely
punctate, each puncture with a short but distinctive seta; the interstices are very convex and
shiny. Males have the metatibiae arcuate and with two spines on the inner surface near the
distal 0.25; the metafemora are prominently pubescent on the inner surface.

Description. — Form: Elongate-oval. Size: Holotype 1.92 mm long, 0.84 mm wide. Color: Dorsal surface and
labrum dark brown; maxillary palpi and antennae testaceous. Ventral surface dark brown except legs, elytral eipileura and
inflexed margin of pronotum brown. Head: Length 0.24 mm. Width 0.44 mm. Frons coarsely punctured, some punctures
nearly confluent; interstices shining; posterior margin slightly emarginate to receive scintilla. Frontoclypeal suture
straight. Clypeus microreticulate. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate and
setose; each lobe symmetrical arc; median emargination ended above midlength of labrum. Maxillary palpus with
following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.32/0.14/0.22; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly
straight, median surface evenly, extremely slightly arcuate; palpomere 4 widest slightly past midlength. Mentum wider
than long, surface moderately shining, finely punctulate. Submentum microreticulate. Genae shining; lateral area of each
gena with well developed foveola; posterior ridge weakly developed. Postgena with microreticulation slightly larger than
that of submentum. Last five antennomeres pubescent. Eyes slightly less than 0.17 interocular distance in width. Thorax:
Pronotum length at midline 0.44 mm; maximum width (at approximately midlength) 0.62 mm; sides margined,
denticulate; sides moderately produced at middle, slightly arcuate and convergent to anterior angle, sinuate and
convergent to posterior; anterior border 0.48 mm wide, straight and nearly perpendicular to midline in lateral 0.25,

Western Hemisphere Hydraenidae

117

Figs. 37 A - B, Aedeagi of Hydraena holotypes. (A) H. alternata. (B) H. campbelli.

moderately arcuate to rear in middle 0.50, posterior border 0.52 mm wide, slightly arcuate to rear. Posterointernal
foveolae well developed; punctures in foveola similar to those on disc. Posterointernal, anteroexternal foveolae and
interfoveolar depression all confluent, in form of distinct, explanate surface. Anteroexternal foveolae well developed,
each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior region of pronotum.
Transverse foveola slightly developed, punctures separated by thin walls. Disc relatively dull, punctures large, deep and
close set; interstices approximately 0.50 puncture diameter, rounded, on various levels, appearance somewhat rugulose,
punctures each with seta extended above cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate
hind margin, prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin, median
carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to
posterior; median carina extended to base of intercoxal process; intercoxal process relatively narrow, sides tapered, apex
blunt, width at apex 0.33 distance between internal and median carinae. Metasternum with plaques moderately
developed, triangular, median surfaces nearly parallel; 0.38 length of metasternum in midline; plaques flat in cross
section. Elytra: Length 1.32 mm. Maximum width (at midlength) 0.84 mm. Surface shining, disc with 10 rows of
punctures between suture and humeral callus, rows quite regular; most punctures round; intervals 2, 4, 6, 8 and 10
(numbered from suture) markedly elevated; width of all intervals approximately equal to puncture diameter; adjacent
punctures of row nearly contiguous; each puncture with seta. Explanate margin broad, extended to apices, with
serrations along entire margin; serrations slightly closer near apices. Elytral apices, in dorsal aspect, gradually rounded;
in posterior aspect, elytral margin elevated very slightly, obliquely toward suture, in form of angle with opposite elytron.
Abdomen: Intercoxal segment flat, nearly equilateral triangle, posterior margin arcuate. Glabrous segments at apex
weakly produced. Segment 7 with emargination at apex. Legs: Protibia excavate on inner surface at apex. Metatibia
arcuate, with two prominent spines on inner surface at apical 0.25. Metafemur prominently pubescent on inner surface.
Genitalia: Aedeagus as illustrated (Fig. 37A)(14 examined).

Natural History. - Hans Reichardt collected this species in association with Hydraena
prieto “ex under stones in a small creek in the mountains”. I have collected it at the margin of a

Quaest. Ent., 1980, 16 (1,2)

118

Perkins

stream flowing through a pine forest meadow in the mountains of Durango, Mexico. The
margins of this stream were composed of rather hard-packed gravel; consocies included
Ochthebius madrensis and O. mexcavatus.

Distribution. - (Fig. 34B). The mountains of Durango, Mexico.

Etymology. - Latin, alternata (alternating). This name refers to the elevated alternate
intervals of the elytra.

The scintillabella Subgroup

Most members of this subgroup, like those of the leechi and alternata Subgroups, have a
well developed scintilla. However, males have the metatibiae straight, without a brush of hairs
or prominent spines. Males of the leechi Subgroup have the metatibiae markedly arcuate and
with a brush of hairs (Fig. 32D), whereas those of the alternata Subgroup are likewise arcuate
but have two prominent spines near the distal 0.25.

Adults of a few species of the scintillabella Subgroup, such as H. terralta and H. alterra,
have the scintilla quite narrow, while in others, such as H. colombiana and H. exilipes , it is
barely perceptible. In H. ozarkensis adults, the scintilla is apparent in males, barely perceptible
in certain females, and imperceptible in other females. In H. zapatina adults a scintilla is not
apparent, although the pronotum is very smooth in the appropriate location, in males.

Aedeagal affinities, which form morphoclines, help “tie” problem species characterized by
absence of a scintilla, to their close relatives which have the scintilla more apparent. A
discussion of this topic is developed in more detail in the section on phylogeny.

The scintillabella Subgroup, which currently consists of 17 species, ranges from the eastern
United States (Ozark Plateau and Appalachian Mountains) south through Mexico to
Paraguay.

27. Hydraena scintillabella new species
(Figs. 38B, 167)

Type-locality. - 23 km. E. El Colegio, Cundinamarca, Colombia.

Type-specimen. - The holotype male (unique) is deposited in USNM. Paul and Phyllis
Spangler collected this specimen, March 9, 1969.

Diagnosis. - The well developed scintilla, absence of plaques, plus the dark coloration and
smooth, shiny dorsum combine to make adults of this attractive species very distinctive. The
pronotal fascia and head are a deep, rich dark brown, contrasting attractively with the
testaceous palpi. The reflected light passing through the scintilla produces an amber glow. The
hydrofuge pubescence of the metasternum appears to be slightly longer in the region usually
occupied by plaques.

Description. — Form: Elongate. Size: Holotype 1 .64 mm long, 0.66 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum light brown at anterior and
posterior 0.25, dark brown in center 0.50; sides slightly lighter than center. Elytra brown. Ventral surface dark brown
except legs, elytral epipleura and inflexed margin of pronotum brown. Head: Length 0.20 mm. Width 0.40 mm. Frons
finely and sparsely punctured, many interstices five times puncture diameter; surface very shiny; posterior margin not
emarginate. Frontoclypeal suture straight. Clypeus finely and sparsely punctulate, very shiny except at extreme sides.
Labroclypeal suture slightly arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median
emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.28/0.12/0.22; palpomere 2 bent outward at approximately midlength; apices of

Western Hemisphere Hydraenidae

119

palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly straight in basal 0.33, arcuate in
apical 0.66, median surface evenly, extremely slightly arcuate; palpomere 4 widest slightly past midlength. Mentum
wider than long, surface shining, finely punctulate. Submentum microreticulate. Genae shining; lateral area of each
gena with well developed foveola; posterior ridge absent. Postgena with microreticulation slightly larger than that of
submentum. Last five antennomeres pubescent. Eyes slightly less than 0.17 interocular distance in width. Thorax:
Pronotum length at midline 0.40 mm; maximum width (at approximately midlength) 0.54 mm; sides margined,
denticulate; sides moderately produced at middle, slightly arcuate and convergent to anterior angle, slightly sinuate and
convergent to posterior; anterior border 0.44 mm wide, straight and nearly perpendicular to midline in lateral 0.25,
moderately arcuate to rear in middle 0.50; posterior border 0.48 mm wide, slightly arcuate to rear. Posterointernal
foveolae moderately developed; punctures in foveola similar to those on disc. Posteroexternal foveolae moderately
developed. Interfoveolar depression slightly developed. Area between external foveolae weakly elevated. Anteroexternal
foveolae well developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of
anterior region of pronotum. Transverse foveola not developed, punctures in this area somewhat closer together than on
disc. Disc extremely shiny, punctures fine, separated by puncture diameter near anterior and posterior borders, and by
two to three times puncture diameter in middle; punctures with seta extended above cuticle in dry specimens. Scintilla
distinct, flat, impunctate shelf with arcuate hind margin. Prosternum carinate, carina produced anteriorly as very short
spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and
external carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal
process relatively broad, sides parallel in apical 0.50, apex blunt, width at apex subequal distance separating internal
and median carinae. Metasternum lacking plaques. Small, cariniform tubercle just lateral to normal location of plaques
but on right side only, left side without tubercle. Elytra: Length 1.06 mm. Maximum width (at midlength) 0.66 mm.
Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most punctures
round; intervals not elevated, width approximately equal to puncture diameter, as are interstices between adjacent
punctures of row; punctures each with seta. Explanate margin quite narrow, ended near posterior 0.20, with extremely
fine serrations near apices. Elytral apices, in dorsal aspect, slightly truncate; in posterior aspect, elytral margin elevated
obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly equilateral
triangle; posterior margin straight. Glabrous segments at apex moderately produced, arched markedly to venter.
Segment 7 emarginate at apex, and asymmetrical. Legs: Profemur with prominent cariniform tubercle on inner surface
at base. Protibia arcuate, expanded in apical 0.33, with prominent group of setae at base of enlargement. Mesotibia
flattened on inner surface in apical 0.33. Metatibia with lateral surface straight, medial surface slightly arcuate, widest
near apical 0.33. Genitalia: Aedeagus as illustrated (Fig. 38B)(1 examined).

Distribution. - (Fig. 167). Known only from type-locality near El Colegio in Cundinamarca,
Colombia.

Etymology. - Latin, scintilla (spark) plus bella (beautiful). This name refers to the
attractiveness of adults and their pronotal scintilla.

Remarks. - The holotype has a small, cariniform prominence on the metasternum just
lateral to the area usually occupied by plaques (but which are absent from adults of this
species). This cariniform prominence is present on the right side only. No other Western
Hemisphere Hydraena now known has such a metasternal modification.

28. Hydraena scintillutea new species
(Figs. 38A,167)

Type-locality. - Jaboticatubas, km 117, Serra do Cipo, Minas Gerais, Brazil.

Type-specimens. - The holotype male is deposited in MSP. One male paratype, with same
data, is deposited in USNM. These specimens were collected by Vanin and Froehlich, October
7, 1975.

Diagnosis. - Coarsely, densely punctate pronotum with a well demarcated, rectangular,
dark brown macula on the disc which is nicely highlighted by the surrounding testaceous
borders, plus a large scintilla serve to distinguish adults of H. scintillutea. The scintilla is very
apparent not only because of its large size, but also because its shiny surface contrasts with the
duller pronotum.

Description. — Form: Ovate. Size: Holotype 1.36 mm long, 0.58 mm wide. Color: Head black except maxillary
palpi and antennae testaceous. Pronotum with rectangular dark brown macula on disc, remainder testaceous. Elytra

Quaest. Ent., 1980, 16 (1,2)

Figs. 38A - D, Aedeagi of Hydraena holotypes. (A) H. scintillutea. (B) H. scintillabella. (C) H. alterra. (D) H. terralta.

Western Hemisphere Hydraenidae

121

brown. Venter dark brown. Legs, inflexed margin of pronotum and elytral epipleura testaceous. Head: Length 0.22 mm;
width 0.36 mm. Frons densely, closely punctate. Frontoclypeal suture slightly arcuate. Clypeus microreticulate,
moderately punctate. Labroclypeal suture straight. Labrum microreticulate, bilobed, median emargination ended at
midlength. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4 respectively: 0.20/0.09/0.16;
palpomere 4 asymmetrical, widest near midlength. Mentum wider than long, dull, microreticulate. Submentum
microreticulate. Genae shining, foveolate laterally; posterior ridge absent. Postgena microreticulate. Thorax: Pronotum
length at midline 0.32 mm; maximum width (slightly behind midlength) 0.48 mm; sides margined, denticulate,
moderately produced at middle, slightly arcuate and convergent to anterior angles, sinuate and convergent to posterior
angles; anterior border 0.40 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate
to rear in middle 0.50; posterior border 0.43 mm wide, slightly arcuate to rear. Posterointernal foveolae well developed,
punctation similar to that on disc. Posteroexternal foveolae slightly developed. Interfoveolar depression moderately
developed. Anteroexternal foveolae well developed, extended over slightly more than 0.25 width of anterior region of
pronotum. Transverse foveola not developed, punctures in this area closer together than those on disc. Disc dull, densely,
moderately coarsely punctate, punctures apparently without setae. Scintilla large, posterior margin markedly arcuate.
Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin carina; carina sinuate in
lateral view. Mesosternum with internal and external carinae divergent from anterior to posterior; median carina
extended to base of intercoxal process; intercoxal process relatively narrow, apex blunt, width at apex 0.33 distance
between internal and median carinae. Metasternum with plaques narrow, slightly elevated, microreticulate, slightly
convergent anteriorly; plaques separated at base by three times plaque width; width of each plaque less than that of
intercoxal process. Elytra: Length 0.88 mm; maximum width (slightly behind midlength) 0.58 mm. Disc moderately
dull, with 10 rows of large punctures between suture and humeral callus, rows slightly irregular near suture in basal
0.25; intervals very narrow, zig-zag; interstices between punctures of row equally narrow. Explanate margin well
developed, ended near posterior 0.14, edge extremely finely serrate. Elytral apices, in dorsal aspect, slightly truncate; in
posterior aspect, elytral margin elevated obliquely toward suture, in form of slight angle with opposite elytron.
Abdomen: Intercoxal segment flat, nearly an equilateral triangle; posterior margin straight. Glabrous segments at apex
markedly produced, arched ventrad; sternum 6 with oval depression in middle; tergum 7 not emarginate at apex. Legs:
Profemur slightly excavate on inner surface in basal 0.50. Protibia slightly arcuate, inner surface expanded in apical
0.33. Other legs slender, unmodified. Genitalia: Aedeagus as illustrated (Fig. 38A)(2 examined).

Natural History. - The label notation, “riacho temporario” accompanies the specimens.

Distribution. - (Fig. 167). Presently known only from type-locality near Jaboticatubas in
the state of Minas Gerais, Brazil.

Etymology. - Latin, scintilla (spark) plus lutea (yellow). This name refers both to the well
developed scintilla and the distinctive testaceous borders of the pronotum which contrast
attractively with the black macula.

29. Hydraena alt err a new species
(Figs. 38C,167)

Type-locality. - Jaboticatubas, km 121, Serra do Cipo, Minas Gerais, Brazil.

Type-specimens. - The holotype male and allotype with identical data are deposited in
MSP. Paratypes (2 males, 2 females) are deposited in MSP, USNM and PDP. These
specimens were collected by Vanin and Froehlich, October 7, 1975.

Diagnosis. - Small size (1.28 mm long), dark color, absence of plaques, small scintilla, and
rather coarsely punctate pronotum serve to distinguish H. alterra from other Brazilian
members of the leechi group. The aedeagus should be studied to reliably distinguish males of
this species from those of H. terralta.

Description. — Form: Ovate. Size: Holotype 1.28 mm long, 0.56 mm wide. Color: Dorsum of head and pronotal
disc black, remainder brown. Head: Length 0.22 mm; width 0.34 mm. Frons closely, moderately coarsely punctate,
pubescence rather apparent. Frontoclypeal suture slightly arcuate. Clypeus microreticulate. Labroclypeal suture straight.
Labrum microreticulate, bilobed, median emargination ended at midlength. Maxillary palpus with following lengths (mm)
of palpomeres 2, 3 and 4 respectively: 0.22/0.08/0.14; palpomere 4 slightly asymmetrical, widest near midlength. Mentum
wider than long, microreticulate, punctulate. Submentum microreticulate. Genae shiny, foveolate laterally; posterior ridge
absent, Postgena microreticulate. Thorax: Pronotum length at midline 0.30 mm; Maximum width (slightly behind
midlength) 0.43 mm; sides margined, denticulate, moderately produced at middle, slightly arcuate and convergent to
anterior angles, slightly sinuate and convergent to posterior angles; anterior border 0.36 mm wide, straight and nearly

Quaest. Ent., 1980, 16 (1,2)

122

Perkins

perpendicular to midline in lateral 0.25, slightly arcuate to rear in middle 0.50; posterior border 0.40 mm wide, very
slightly arcuate to rear. Posterointernal foveolae moderately developed, punctate as disc. Posteroexternal foveolae
moderately developed. Interfoveolar depression moderately developed. Anteroexternal foveolae well developed, each
extended across 0.25 width of anterior region of pronotum. Transverse foveola shallow, densely punctate, punctures
closer together than those on disc. Disc dull, densely, moderately coarsely punctate, setae unapparent. Scintilla small,
very narrow. Prosternum carinate, thin carina between coxae. Mesosternum with internal and external carinae divergent
from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process narrow, apex blunt,
width at apex 0.50 distance between internal and median carinae. Metasternum without plaques. Elytra: Length
0.68 mm; maximum width (slightly past midlength) 0.56 mm. Disc dull, with 10 rows of large, deep punctures between
suture and humeral callus; intervals narrow, zig-zag; interstices between punctures of row equally narrow. Explanate
margin well developed, ended near posterior 0.14, finely serrate. Elytral apices rounded in dorsal view; in posterior
aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal
segment flat, nearly an equilateral triangle, posterior border straight. Glabrous segments at apex moderately produced.
Legs: Protibia very slightly excavate, widest near distal 0.20, not expanded. Other legs slender, unmodified. Genitalia:
Aedeagus as illustrated (Fig. 38C).(3 examined).

Natural History. - The label notation, “EM Leiothrix” accompanies the specimens.

Distribution. - (Fig. 167). Presently known only from the type-locality near Jaboticatubas
in the highlands of Minas Gerais, Brazil.

Etymology. - Latin, alta (high) plus terra (land). I refer to the highlands of Brazil, the
habitat of this species. The name alterra is also meant to symbolize the close relationship to H.
terralta, and the shorter word, alterra , serves as a reminder that adults of this species are
shorter in body length and aedeagal length than are those of terralta.

30. Hydraena terralta new species
(Figs. 38D,167)

Type-locality. - Jaboticatubas, km 121, Serra do Cipo, Minas Gerais, Brazil.

Type-specimen. - The holotype male (unique) is deposited in MSP. This specimen was
collected by Vanin and Froehlich, October 7, 1975.

Diagnosis. - The aedeagus should be studied to reliably distinguish members of this species
from those of H. alterra. H. alterra lacks plaques whereas the one specimen of H. terralta now
known has very small, oval plaques. The very small size of the plaques, however, suggests that
this feature may prove unreliable for identification purposes.

Description. — Form: Ovate. Size: Holotype 1.36 mm long, 0.58 mm wide. Color: Dorsum of head and pronotal
disc black, remainder brown. Head: Length 0.22 mm; width 0.34 mm. Frons closely, moderately coarsely punctate.
Frontoclypeal suture slightly arcuate. Clypeus microreticulate. Labroclypeal suture straight. Labrum microreticulate,
bilobed, median emargination ended at midlength. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4
respectively: 0.20/0.08/0.14; palpomere 4 slightly asymmetrical, widest near midlength. Mentum wider than long,
microreticulate, punctulate. Submentum microreticulate. Genae shiny, foveolate laterally; posterior ridge absent. Postgena
microreticulate. Thorax: Pronotum length at midline 0.32 mm; maximum width (at midlength) 0.45 mm; sides margined,
denticulate, moderately produced at middle, slightly arcuate and convergent to anterior angles, slightly sinuate and
convergent to posterior angles; anterior border 0.36 mm wide, straight and nearly perpendicular to midline in lateral 0.25,
slightly arcuate to rear in middle 0.50; posterior border 0.40 mm wide, very slightly arcuate to rear. Posterointernal
foveolae moderately developed, punctate as disc. Posteroexternal foveolae moderately developed. Interfoveolar depression
moderately developed. Anteroexternal foveolae well developed, each occupying about 0.25 width of anterior region of
pronotum. Transverse foveola shallow, densely punctate, punctures closer together than those on disc. Disc dull, densely,
moderately coarsely punctate, setae unapparent. Scintilla small, very narrow. Prosternum carinate, thin carina between
coxae. Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to
base of intercoxal process, intercoxal process narrow, apex blunt, width at apex 0.50 distance between internal and median
carinae. Metasternum with plaques very small, nearly indistinguishable ovals near hind margin. Elytra: Length 0.88 mm;
maximum width (near midlength) 0.58 mm. Disc dull, with 10 rows of large, deep punctures between suture and humeral
callus; intervals narrow, zig-zag; interstices between punctures of row equally narrow. Explanate margin well developed,
ended near posterior 0.14, finely serrate. Elytral apices rounded in dorsal view; in posterior aspect, elytral margin elevated
obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly an equilateral
triangle, posterior border straight. Glabrous segments at apex moderately produced. Legs: Profemur with very small

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tubercle on inner surface near midlength. Protibia slightly excavate on inner surface in distal 0.25. Other legs slender,
unmodified. Genitalia: Aedeagus as illustrated (Fig. 38D)(1 examined).

Natural History. - The label notation, “EM Leiothrix ” accompanies the specimen.

Distribution. - (Fig. 167). Presently known only from the type-locality near Jaboticatubas
in the highlands of Minas Gerais, Brazil.

Etymology. - Latin, terra (land) plus alta (high). I refer to the highlands of Brazil, where
this species is found. The name terralta is also meant to symbolize the close relationship to H.
alterra, the putative sister-species. Additionally, since terralta is a longer word than alterra , it
serves as a reminder that adults of this species are longer in aedeagal and body length than are
those of H. alterra.

31. Hydraena pavicula new species
(Figs. 39A,167)

Type-locality. - Above Huinco, 8400 feet, Lima, Peru.

Type-specimen. - The holotype male (unique) is deposited in USNM. Harley P. Brown
collected this specimen, November 12, 1971.

Diagnosis. - Distinguished from other members of the leechi Group which have a well
developed scintilla by the markedly microreticulate lateral depressed areas of the pronotum and
the microreticulation in and surrounding the elytral punctures. Adults are uniformly dark
brown, nearly black on the dorsal surface, the legs and palpi being slightly lighter. The plaques
are small, indistinctive ovals at the posterior 0.20 of the metasternum. Males have the protibiae
expanded in the distal 0.50; the metatibiae are very slender, their greatest width being less than
that of the protibiae.

Description. — Form: Elongate. Size: Holotype 1.80 mm long, 0.76 mm wide. Color: Dorsal surface dark brown.
Maxillary palpi and antennae testaceous. Ventral surface dark brown except legs, elytral epipleurae and inflexed margin
of pronotum brown. Head: Length 0.24 mm. Width 0.42 mm. Frons microreticulate, punctation coarse, punctures
separated by 0.50 puncture diameter, or less; surface moderately dull. Frontoclypeal suture weakly arcuate to rear.
Clypeus finely microreticulate at sides, very shiny in middle. Labroclypeal suture arcuate in dorsal aspect. Labrum
bilobed, microreticulate, each lobe symmetrical arc; median emargination ended slightly above midlength of labrum.
Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.28/0.12/0.20; palpomere 2 bent
outward at approximately midlength; palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly
straight in basal 0.33, arcuate in apical 0.66, median surface arcuate; palpomere 4 widest near apical 0.33. Mentum wider
than long, surface moderately shining, microreticulate. Submentum microreticulation similar to mentum. Genae shining;
lateral area of each gena with well developed foveola; posterior ridge slightly developed. Postgena with microreticulation
similar to that of submentum. Last five antennomeres pubescent. Eyes 0.20 interocular distance in width. Thorax:
Pronotum length at midline 0.42 mm; maximum width (at approximately midlength) 0.56 mm; sides margined,
denticulate; sides moderately produced at middle, slightly arcuate and convergent to anterior angle, sinuate and
convergent to posterior; anterior border 0.44 mm wide, straight and nearly perpendicular to midline in lateral 0.25,
moderately arcuate to rear in middle 0.50; posterior border 0.52 mm wide, slightly arcuate to rear. Posterointernal foveolae
well developed; punctures in foveola closer together than those on disc, some confluent. Anteroexternal and posteroexternal
foveolae confluent, producing explanate sides of pronotum; microreticulation in this area well developed. Transversal
foveola moderately developed, punctures closer together than punctures on disc. Disc moderately dull, microreticulate,
punctures separated by one-two times puncture diameter, microreticulation extremely lightly impressed on interstices,
reflections interrupted; each puncture with distinctive seta extended above cuticle in dry specimens. Scintilla distinct, flat,
impunctate shelf with arcuate hind margin. Prosternum carinate, carina produced anteriorly as very short spine; coxae
separated by thin, median carina, latter sinuate line in lateral aspect. Mesosternum with internal and external carinae
divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively
broad, sides nearly parallel, apex blunt, width at apex 0.66 distance between internal and median carinae. Metasternum
with low ridge posterior to intercoxal process; plaques small ovals at posterior 0.20. Elytra: Length 1.18 mm. Maximum
width (at midlength) 0.76 mm. Surface dull, disc with 10 rows of punctures between suture and humeral callus, rows quite
regular; most punctures with irregular margins, microreticulate within punctures; surface uneven, reflections interrupted;
intervals not elevated, width slightly greater than puncture diameter, interstices between adjacent punctures of row
generally smaller; each puncture with seta. Explanate margin quite narrow, ended near posterior 0.20, with prominent

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serrations near anterior angles. Elytral apices, in dorsal aspect gradually rounded; in posterior aspect, elytral margin
elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than
long, posterior margin straight. Glabrous segments at apex moderately produced. Segment 7 with deep, oblique
meargination on left side near apex. Legs: Profemur with oblique carina on inner surface at base. Protibia enlarged on
inner surface in apical 0.50. Metatibia gradually enlarged from base to apex. Genitalia: Aedeagus as illustrated
(Fig. 39A)(1 examined).

Distribution. - (Fig. 167). Presently known only from the type-locality near Huinco in the
department of Lima, Peru.

Etymology. - Latin, pavicula (rammer). Named in reference to the ram-like appearance of
the aedeagus (lateral view).

32. Hydraena costiniceps new species
(Figs. 39B,167)

Type-locality. - Salta, Salta, Argentina.

Type-specimen. - The holotype male (unique) is deposited in USNM. Paul and Phyllis
Spangler collected this specimen, May 18, 1969.

Diagnosis. - Males of H. costiniceps are distinguished from those of other species which
have a pronotal scintilla by the unmodified legs, densely punctate pronotum, plaque shape and
aedeagal form (Fig. 39B). The pronotum is densely punctate, most punctures separated by less
than puncture diameter; the surface is relatively shiny, however, due to the very smooth, flat
interstices. The plaques are triangular, the anterior ends being ill-defined, not well demarcated.

Description. — Form: Elongate. Size: Holotype 1.60 mm long, 0.72 mm wide. Color: Head with dorsal surface and
labrum dark brown; maxillary palpi and antennae testaceous. Pronotum testaceous at anterior and posterior 0.25, dark
brown in center 0.50; sides slightly lighter than center. Elytra brown approximately midway in color between extremes of
pronotum. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum brown. Head:
Length 0.20 mm. Width 0.40 mm. Frons moderately punctured, interstices equal to or slightly greater than puncture
diameter; setae quite distinctive; surface shining; posterior margin emarginate in midline to receive scintilla. Surface
posterior to emargination with transverse ridges. Frontoclypeal suture straight. Clypeus microreticulate. Labroclypeal
suture arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended
at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4,
respectively: 0.30/0.12/0.22; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not
especially expanded; palpomere 4 with lateral surface slightly expanded at apical 0.33, median surface arcuate;
palpomere 4 widest slightly past midlength. Mentum wider than long, surface moderately shining, microreticulate.
Submentum microreticulate. Genae shining; lateral area of each gena with well developed foveola; posterior ridge nearly
imperceptible. Postgena with microreticulation slightly larger than that of submentum. Last five antennomeres pubescent.
Eyes slightly less than 0.25 interocular distance in width. Thorax: Pronotum length at midline 0.40 mm; maximum width
(at approximately midlength) 0.54 mm; sides margined, denticulate; sides relatively weakly produced at middle, slightly
arcuate and slightly convergent to anterior angle, very slightly sinuate and slightly convergent to posterior; anterior border
0.44 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50;
posterior border 0.48 mm wide, slightly arcuate to rear. Posterointernal foveolae moderately developed; punctures in
foveola similar to those on disc. Posteroexternal foveola delimited by a very shallow depression with punctation somewhat
closer than that of disc. Interfoveolar depression absent. Area between external foveolae weakly elevated. Anteroexternal
foveolae well developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior
region of pronotum. Transverse foveola not developed, punctures in this area somewhat closer together than punctures on
disc. Disc shining, punctures close together and fine, separated by less than puncture diameter to thin walls; punctures
each with distinctive seta extended above cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate
anterior and posterior margins. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by
thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from
anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively narrow, sides
parallel, apex blunt, width 0.66 distance between internal and median carinae. Metasternum with plaques moderately
developed, triangular, median margins divergent moderately from posterior to anterior; plaques nearly 0.50 length of
metasternum in midline; width of each plaque at posterior 0.66 width of intercoxal process; plaques flat in cross section.
Elytra: Length 1.07 mm. Maximum width (at midlength) 0.72 mm. Surface shining, disc with 10 rows of punctures
between suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width approximately
equal to 0.66 puncture diameter, as are interstices between adjacent punctures of a row; punctures each with a seta.

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125

Figs. 39A - D, Aedeagi of Hydraena holotypes. (A) H. pavicula. (B) H. costiniceps. (C) H. zapatina. (D) H. colombiana.

Explanate margin quite narrow, ended near posterior 0.10, with extremely fine serrations near apices. Elytral apices, in
dorsal aspect, moderately truncate; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle
with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin arcuate. Glabrous segments
at apex moderately produced. Apical segment semi-circular, slightly emarginate at apex. Legs: Without apparent
modification. Genitalia: Aedeagus as illustrated (Fig. 39B)(1 examined).

Distribution. - (Fig. 167). Presently known only from the type-locality, Salta, Argentina.

Etymology. - Latin, costa (ridge) plus ina (diminutive) plus ceps (head). I refer to the very
small ridges on the occipital region of the head, above which is the scintilla.

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33. Hydraena germaini d’Orchymont
(Fig. 167)

Hydraena germaini d’Orchymont, 1923:38. (holotype depository uncertain; type-locality: Cochabamba, Bolivia).

According to d’Orchymont (1923) the holotype is deposited in the Museum National
d’Histoire Naturelle, Paris. Through the courtesy of that institution I have received for study a
single female paratype from the type-locality. There is a distinct possibility that further search
may result in finding the holotype, consequently I am not designating a lectotype at this time.

Diagnosis. - Adults are very similar to those of H. costiniceps, differing primarily in less
dense pronotal punctation. A more definitive diagnosis must await discovery of males and
description of the aedeagus.

Description. — Form: Elongate. Size: Paratype female studied 1.64 mm long, 0.74 mm wide. Color: Head with
dorsal surface dark brown except almost black areas near eyes; labrum dark brown; maxillary palpi testaceous; antennae
testaceous. Pronotum testaceous except transverse, rectangular, brown (lighter than head) macula on disc approximately
0.20 mm long, 0.38 mm wide; macula at borders blended into surrounding testaceous areas. Elytra brownish, intermediate
in darkness between pronotal macula and pronotal lateral areas. Ventral surface dark brown except maxillae, legs, elytral
epipleura and inflexed margin of pronotum light brown. Head: Length 0.23 mm. Width 0.41 mm. Frons moderately
punctured, interstices equal to or slightly greater than puncture diameter; surface shining. Frontoclypeal suture arcuate to
rear. Clypeus microreticulate. Labroclypeal suture straight across middle when in dorsal aspect. Labrum bilobed,
microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary
palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.29/0.1 1/0.21; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly
straight in basal 0.33, arcuate in apical 0.66, median surface evenly, extremely slightly arcuate; palpomere 4 widest at
distal 0.33. Mentum wider than long, surface moderately shining, microreticulate. Submentum microreticulate. Genae
shining; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with microreticulation
slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly less than 0.25 interocular distance
in width. Thorax: Pronotum length at midline 0.40 mm; maximum width (at approximately midlength) 0.56 mm; sides
margined, denticulate; sides relatively weakly produced at middle, slightly arcuate and slightly convergent to posterior;
anterior border 0.46 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in
middle 0.50; posterior border 0.54 mm wide, slightly arcuate to rear. Posterointernal foveolae slightly developed; punctures
in foveola slightly closer together than those on disc. Posteroexternal foveola delimited by very shallow depression with
punctation somewhat closer than that of disc. Interfoveolar depression absent. Anteroexternal foveolae well developed,
each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior region of pronotum.
Transverse foveola not developed, punctures in this area somewhat closer together than punctures on disc. Disc shining,
punctures fine and deeply impressed, separated by one-two times puncture diameter; most punctures with distinctive seta
extended above cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate hind margin. Prosternum
carinate, carina produced anteriorly as very short spine; coxae separated by thin, median carina; carina sinuate line in
lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median carina
extended to base of intercoxal process; intercoxal process relatively narrow, sides nearly parallel, apex blunt, width at apex
0.66 distance between internal and median carinae. Metasternum with plaques well developed, straight, parallel, tapered
from posterior to anterior; plaques 0.50 length of metasternum in midline; greatest width of each plaque subequal to width
of intercoxal process at its midlength; plaques separated posteriorly by twice plaque width; plaques separated anteriorly by
approximately six times plaque width; plaques flat in cross section. Elytra: Length 1 .06 mm. Maximum width (at
midlength) 0.74 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite
regular; most punctures round; intervals not elevated, width approximately equal to 0.66 puncture diameter, interstices
between adjacent punctures of row generally smaller; each puncture with seta. Explanate margin quite narrow, ended near
posterior 0.20, with serrations near anterior angles and in posterior 0.33. Elytral apices, in dorsal aspect, truncate; in
posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen:
Intercoxal segment flat, wider than long, posterior margin arcuate. Legs: Protibia weakly arcuate in apical 0.50. Genitalia:
Male unknown.

Distribution. - (Fig. 167). Presently known only from the type-locality, Cochabamba,
Bolivia.

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127

34. Hydraena colombiana new species
(Figs. 39D,167)

Type-locality. - 1 1 km. N. Bogota, Cundinamarca, Colombia.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. Paratypes with same data are in USNM(2) and PDP(2). These specimens were
collected by Paul and Phyllis Spangler, March 1-8, 1969.

Diagnosis. - Plaques are narrow, slightly arcuate, tapered to an acute apex anteriorly;
basally they are separated by about four times the width of a plaque. Males have the pronotal
scintilla slightly developed, the legs lacking modifications. The scintilla of females is extremely
narrow, nearly imperceptible. The aedeagus (Fig. 39D) is very distinctive.

Description. — Form: Elongate. Size: The holotype is 1.60 mm long, 0.64 mm wide. Color: Head with dorsal
surface dark brown; labrum dark brown; maxillary palpi brown; antennae brown. Pronotum brown at anterior and
posterior 0.25, dark brown in center 0.50. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and
inflexed margin of pronotum brown. Head: Length 0.20 mm. Width 0.38 mm. Frons moderately punctured, interstices
equal to or slightly greater than puncture diameter; surface shining, posterior margin emarginate to receive scintilla.
Frontoclypeal suture straight. Clypeus microreticulate at sides, sparsely in midline. Labroclypeal suture arcuate in dorsal
aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at approximately
midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.26/0.10/0.20; palpomere 2 bent outward at approximately midlength; apices palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface nearly straight in basal 0.33, arcuate in apical 0.66, median surface evenly,
extremely slightly arcuate; palpomere 4 widest near midlength. Mentum wider than long, surface moderately shining,
finely microreticulate. Submentum microreticulate. Genae moderately shining; lateral area of each gena with well
developed foveola; posterior ridge nearly imperceptible. Postgena with punctation slightly larger than that of submentum.
Last five antennomeres pubescent. Eyes slightly less than 0.20 interocular distance in width. Thorax: Pronotum length at
midline 0.38 mm; maximum width (at approximately midlength) 0.52 mm; sides margined, denticulate; sides relatively
slightly produced at middle, slightly arcuate and slightly convergent to anterior angle, very slightly sinuate and slightly
convergent to posterior; anterior border 0.42 mm wide, straight and nearly perpendicular to midline in lateral 0.25;
moderately arcuate to rear in middle 0.50; posterior border 0.48 mm wide, slightly arcuate to rear. Posterointernal foveolae
weakly developed; punctures in foveola somewhat closer together than those on disc. Posteroexternal foveola delimited by
very shallow depression with punctation somewhat closer than that of disc. Interfoveolar depression shallow and broad.
Area between foveolae not elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped,
extended across slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not developed, punctures
in this area somewhat closer together than punctures on disc. Disc shining, punctures fine, separated by 0.50 puncture
diameter near anterior and posterior borders by puncture diameter in middle; punctures each with distinctive seta extended
above cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate hind margin. Prosternum carinate,
carina produced anteriorly as very short spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect.
Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to base of
intercoxal process; intercoxal process relatively narrow, sides nearly parallel, apex rounded, width slightly less than 0.50
distance between internal and median carinae. Metasternum with plaques well developed, slightly arcuate, triangular,
converging strongly from posterior to anterior; plaques 0.50 length of metasternum in midline; greatest width of each
plaque subequal to width of intercoxal process at its midlength; plaques separated posteriorly by approximately four times
greatest width of a plaque; plaques separated anteriorly by twice plaque width; plaques flat in cross section. Elytra: Length
1.06mm. Maximum width (at midlength) 0.64 mm. Surface shining, disc with 10 rows of punctures between suture and
humeral callus, some rows quite irregular, some punctures random at most anterior, most punctures round; intervals not
elevated, width approximately equal to puncture diameter, as are interstices between adjacent punctures of a row;
punctures each with a seta. Explanate margin quite narrow, ended near posterior 0.20, with extremely fine serrations near
apices. Elytral apices, in dorsal aspect, slightly truncate; in posterior aspect, elytral margin elevated obliquely toward
suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin
straight. Glabrous segments at apex moderately produced. Segment 7 emarginate at apex. Legs: Without apparent
modification. Genitalia: Aedeagus as illustrated (Fig. 39D)(3 examined).

Distribution. - (Fig. 167). Presently known only from the type-locality near Bogota,
Colombia.

Etymology. - Latin, colombiana , in reference to the geographical distribution.

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35. Hydraena paraguayensis Janssens
(Fig. 167)

Hydraena paraguayensis Janssens, 1972:259 (lectotype female deposited in 1SNB, here designated; type-locality: Acaray

waterfall, Puerto Presidente Stroessner, Alto Parana, Paraguay).

Diagnosis. - Among the South American species of the leechi group whose adults possess a
pronotal scintilla, H. paraguayensis adults are distinguished by the prosternum, which has a
small shelf between the procoxae and the median carina. Males are not yet known for this
species.

Description. — Form: Elongate-oval. Size: Lectotype 1.40 mm long, 0.62 mm wide. Color: Head with dorsal
surface dark brown; labrum brown; maxillary palpi and antennae testaceous. Pronotum light brown except macula
extended as transverse band from side to side from anterior 0.42 to posterior 0.14, macula lighter at margins. Elytra
midway in color between lighter and darker areas of pronotum. Ventral surface dark brown except legs, elytral epipleura
and inflexed margin of pronotum, brown. Head: Length 0.24 mm. Width 0.36 mm. Frons moderately punctured,
interstices equal to or slightly less than puncture diameter; surface moderately shining. Frontoclypeal suture straight.
Clypeus microreticulate. Labroclypeal suture slightly arcuate when in dorsal aspect. Labrum bilobed, microreticulate,
each lobe asymmetrical arc; median emargination ended slightly above midlength of labrum. Maxillary palpus with
following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.24/0.08/0.16; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly
straight in basal 0.33, arcuate in apical 0.66, median surface arcuate; apical segment widest near distal 0.33. Mentum
nearly quadrangular, surface shining, finely and sparsely punctulate. Submentum microreticulate. Genae shining; lateral
area of each gena with well developed foveola; posterior ridge absent. Postgena with microreticulation slightly larger than
that of submentum. Last five antennomeres pubescent. Eyes 0.16 interocular distance in width. Thorax: Pronotum length
at midline 0.32 mm; maximum width (at approximately midlength) 0.48 mm; sides margined, denticulate; sides
moderately produced at middle, slightly arcuate and slightly convergent to anterior angle, sinuate and convergent to
posterior; anterior border 0.40 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate
to rear in middle 0.50; posterior border 0.44 mm wide, slightly arcuate to rear. Posterointernal foveolae moderately
developed; punctures in foveola similar to those on disc. Posteroexternal foveola delimited by very shallow depression with
punctation somewhat closer than that of disc. Interfoveolar depression very slightly developed. Area between external
foveolae not elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across
slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not developed, punctures in this area
somewhat closer together than punctures on disc. Disc shining, punctures fine, separated by puncture diameter near
anterior and posterior borders, and by twice puncture diameter in middle; most punctures with seta extended above cuticle
in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate hind margin. Prosternum carinate, carina produced
anteriorly into short spine; coxae separated from median carina by thin shelf; carina sinuate line in lateral aspect.
Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to base of
intercoxal process; intercoxal process relatively broad, sides nearly parallel, apex blunt, width at apex equal distance
between internal and median carinae. Metasternum with plaques moderately developed, straight, convergent moderately
from posterior to anterior; each plaque subtriangular, widest at base; plaques 0.43 length of metasternum in midline;
greatest width of each plaque 0.33 width of intercoxal process at its midlength; plaques separated posteriorly by
approximately three times plaque width; plaques flat in cross section. Elytra: length 0.88 mm. Maximum width (at
midlength) 0.62 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite
regular; most punctures round; intervals not elevated, width approximately equal to puncture diameter, as are interstices
between adjacent punctures of row; each puncture without seta. Explanate margin quite narrow, ended near posterior 0.20,
with extremely fine, well separated serrations along entire margin; serrations somewhat closer near apices. Elytral apices,
in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle
with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Legs: Protibia very
slightly arcuate; other legs without apparent modification. Genitalia: Males unknown.

Distribution. - (Fig. 167). Known only from the type-locality near Puerto Presidente
Stroessner in the Department of Alto Parana, Paraguay.

Remarks. - The holotype and two paratypes of H. paraguayensis were requested from the
Institut royal des Sciences Naturelles de Belgique (through E. Janssens). When the shipping
box arrived, however, it was found to contain the pin with holotype label and locality labels, but
the specimen was no longer glued to the card. A search of the box proved fruitless. Therefore,
one of the paratypes was selected to serve as the lectotype, and is herein so designated.

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36. Hydraena plaumanni d’Orchymont
(Fig. 167)

Hydraena plaumanni d’Orchymont, 1937:457. (holotype female in 1SNB; type-locality: Nova Teutonia, Santa Catarina,

Brazil).

Diagnosis. - Distinguished from other Brazilian members of the leechi Group which have a
pronotal scintilla by form of the metasternal plaques, which are arcuate and separated
posteriorly by three times the width of a plaque. Males are not yet known for this species.

Description. — Form: Elongate. Size: Holotype 1.44 mm long, 0.56 mm wide. Color: Head with dorsal surface and
labrum dark brown; maxillary palpi and antennae testaceous. Pronotum testaceous except for transverse, rectangular,
brown (lighter than head) macula on disc approximately 0.10 mm long, 0.30 mm wide; macula at anterior and posterior
borders abruptly disappearing, at sides blended into surrounding testaceous areas. Elytra same color as pronotal macula.
Ventral surface dark brown except maxillae, legs, plaques, elytral epipleura and inflexed margin of pronotum testaceous.
Head: Length 0.20 mm. Width 0.35 mm. Frons coarsely punctured, interstices less than puncture diameter; surface dull.
Frontoclypeal suture straight. Clypeus finely punctulate. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed,
microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary
palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.26/0.08/0.20; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly
straight, medial surface arcuate, widest slightly past midlength. Mentum wider than long, surface shining, punctures fine,
sparse. Submentum microreticulate. Genae moderately shining, punctulate; lateral area of each gena with well developed
foveola; posterior ridge absent. Postgena with microreticulation similar to that of submentum. Last five
antennomeres pubescent. Eyes 0.17 interocular distance in width. Thorax: Pronotum length at midline 0.34 mm;
maximum width (at approximately midlength) 0.47 mm; sides margined, denticulate; sides relatively weakly produced at
middle, slightly arcuate and slightly convergent to anterior angle, slightly sinuate and slightly convergent to posterior;
anterior border 0.39 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in
middle 0.50; posterior border 0.42 mm wide, slightly arcuate to rear. Posterointernal foveolae very slightly developed;
punctures in foveola closer together than those on disc. Posteroexternal foveola delimited by very shallow depression with
punctation somewhat closer than that of disc. Interfoveolar depression absent. Area between external foveolae flat.
Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33
width of anterior region of pronotum. Transverse foveola not developed, although punctures in this area are somewhat
closer together than punctures on disc. Disc moderately shining, punctures fine and deeply impressed, separated by narrow
walls near anterior and posterior borders, and by 0.5- 1.0 times puncture diameter in middle; most punctures with seta
extended above cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate hind margin. Prosternum
carinate, carina produced anteriorly as very short spine; coxae separated by thin, median carina; carina sinuate line in
lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median carina
extended to base of intercoxal process; intercoxal process relatively narrow, sides nearly parallel, apex blunt, width at apex
0.50 distance between internal and median carinae. Metasternum with plaques well developed, slightly arcuate, with
concave side toward midline; 0.50 length of metasternum in midline; greatest width of each plaque subequal to width of
intercoxal process at its midlength; plaques separated posteriorly by approximately twice plaque width; plaques separated
anteriorly by basal width of a plaque; plaques flat in cross section. Elytra: Length 0.92 mm. Maximum width (at
midlength) 0.60 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite
regular; most punctures round; intervals not elevated, width 0.50 puncture diameter, as are interstices between adjacent
punctures of row; each puncture with seta. Explanate margin quite narrow, ended near posterior 0.20, with extremely fine,
well separated serrations along entire margin; serrations somewhat closer near apices. Elytral apices, in dorsal aspect,
gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite
elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous segments at apex
moderately produced. Legs: Without apparent modification. Genitalia: Males unknown.

Distribution. - (Fig. 167). Known only from the type-locality at Nova Teutonia in the state
of Santa Catarina, Brazil.

Remarks. - The holotype is the only specimen I have studied.

37. Hydraena sordida Sharp
(Fig. 167)

Hydraena sordida Sharp, 1882:94 (lectotype female in BMNH, here designated; type-locality: San Joaquin, Baja

Verapaz, Guatemala).

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Perkins

Diagnosis. - The finely, densely punctate pronotum with its well developed scintilla, plus
shape of plaques, which are reduced to small ovals at the posterior 0.20 of the metasternum,
must serve as the characteristics, albeit rather unsatisfactory, to distinguish H. sordida adults.
A more complete diagnosis must await discovery of males.

Description. — Form: Elongate. Size: Lectotype 1 .67 mm long, 0.74 mm wide. Color: Head with dorsal surface
brown; labrum brown; maxillary palpi brown; antennae testaceous. Pronotum brown, lighter toward lateral areas. Elytra
brown. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum brown. Head: Length
0.24 mm. Width 0.42 mm. Frons moderately punctured, most interstices less than puncture diameter; surface moderately
shining. Frontoclypeal suture arcuate to rear. Clypeus microreticulate. Labroclypeal suture arcuate in dorsal aspect.
Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of
labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.28/0.11/0.19;
palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4
with lateral surface nearly straight, medial surface arcuate, widest near midlength. Mentum wider than long, surface
moderately shining, microreticulate. Submentum microreticulation similar to mentum. Genae shining; lateral area of each
gena with well developed foveola; posterior ridge absent. Postgena with microreticulation slightly larger than that of
submentum. Last five antennomeres pubescent. Eyes slightly less than 0.17 interocular distance in width. Thorax:
Pronotum length at midline 0.40 mm; maximum width (at approximately midlength) 0.57 mm; sides margined,
denticulate; sides moderately produced at middle, slightly arcuate and convergent to anterior angle, sinuate and
convergent to posterior; anterior border 0.46 mm wide, straight and nearly perpendicular to midline in lateral 0.25,
moderately arcuate to rear in middle 0.50; posterior border 0.46 mm wide, slightly arcuate to rear. Posterointernal foveolae
well developed; punctures in foveola closer together than those on disc. Posteroexternal foveola well developed.
Interfoveolar depression well developed, disc elevated. Area between external foveolae elevated. Anteroexternal foveolae
well developed, each foveola somewhat crescent shaped, occupying slightly less than 0.33 width of anterior region of
pronotum. Transverse foveola slightly developed, punctures closer together than punctures on disc. Disc moderately dull,
punctures fine, deeply impressed, separated by puncture diameter to nearly confluent; most punctures with seta extended
above cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate hind margin. Prosternum carinate,
carina produced anteriorly into very short spine; coxae separated by thin, median carina; carina sinuate line in lateral
aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to
base of intercoxal process; intercoxal process relatively broad, sides nearly parallel; apex blunt, width at apex nearly 0.66
distance between internal and median carinae. Metasternum with plaques very small ovals at posterior 0.20. Elytra:
Length 1.07 mm. Maximum width (at midlength) 0.74 mm. Surface shining, disc with 10 rows of punctures between
suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width approximately equal to
0.50 puncture diameter, as are interstices between adjacent punctures of a row; each puncture with a seta. Explanate
margin quite narrow, ended near posterior 0.14, with extremely fine, well separated serrations along entire margin;
serrations slightly closer near apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin
elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than
long, posterior margin straight. Legs: Protibiae very slightly arcuate; other legs without apparent modification. Genitalia:
Males unknown.

Distribution. - (Fig. 167). Baja Verapaz, Guatemala.

Remarks. - Other than the lectotype I have seen only four females, two from the
type-locality, and two from San Geronimo. These four specimens are herein designated
paralectotypes.

38. Hydraena puncticollis Sharp
(Fig. 167)

Hydraena puncticollis Sharp, 1882:93 (lectoype female in BMNH, here designated; type-locality: Paso Antonio, 400 feet,

Guatemala).

Diagnosis. - Small size (1.46 mm long), coarse pronotal punctation, and elytral apices,
which do not form an angle with one another in posterior aspect, serve as the diagnostic
features available at this time. Males are unknown. Refer to the remarks section for futher
comments.

Description. — Form: Elongate-oval. Size: Lectotype 1.46 mm long, 0.66 mm wide. Color: Head with dorsal
surface and labrum dark brown; maxillary palpi and antennae brown. Pronotum dark brown except for transverse,
rectangular, black macula on disc approximately 0.16 mm long, 0.34 mm wide; macula at borders blended into
surrounding brownish areas. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed margin

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131

of pronotum, brown. Head: Length 0.19 mm. Width 0.35 mm. Frons coarsely punctured, interstices less than puncture
diameter; surface shining. Frontoclypeal suture straight. Clypeus microreticulate. Labroclypeal suture arcuate when
viewed from above. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4,
respectively: 0.26/0.10/0.20; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not
especially expanded; palpomere 4 with lateral surface nearly straight; median surface evenly, extremely slightly arcuate;
palpomere 4 widest slightly past midlength. Mentum longer than wide, surface moderately shining, finely punctulate.
Submentum evenly, finely microreticulate. Genae shining; lateral area of each gena with well developed foveola;
posterior ridge absent. Postgena with microreticulation slightly larger than that of submentum. Last five
antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width. Thorax: Pronotum length at midline
0.35 mm; maximum width (at approximately midlength) 0.48 mm; sides margined, denticulate; sides moderately
produced at middle, slightly arcuate and slightly convergent to anterior angle, arcuate and slightly convergent to
posterior; anterior border 0.40 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately
arcuate to rear in middle 0.50; posterior border 0.44 mm wide, slightly arcuate to rear. Posterointernal foveolae well
developed; punctures in foveola similar to those on disc. Posteroexternal foveola delimited by very shallow depression
with punctation somewhat closer than that of disc. Anteroexternal foveolae well developed, each foveola somewhat
crescent shaped, extended across slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not
developed, punctures in this area somewhat closer together than punctures on disc. Disc shining, punctures fine,
separated by puncture diameter; each puncture with seta extended above cuticle in dry specimens. Scintilla distinct, flat,
impunctate shelf with arcuate hind margin. Prosternum carinate, carina produced anteriorly as very short spine; coxae
separated by thin median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae
divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively
narrow, sides nearly parallel, apex blunt, width at apex 0.50 distance between internal and median carinae.
Metasternum with plaques well developed, slightly arcuate, convergent moderately from posterior to anterior; plaques
separated posteriorly by approximately three times plaque width; plaques separated anteriorly by plaque width; plaques
slightly rounded in cross section. Elytra: Length 0.92 mm. Maximum width (at midlength) 0.68 mm. Surface shining,
disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most punctures round; intervals
not elevated, width approximately equal to puncture diameter, as are interstices between adjacent punctures of a row;
each puncture with a seta. Explanate margin quite narrow, ended near posterior 0.10, with extremely fine, well
separated serrations along entire margin; serrations somewhat closer near apices. Elytral apices, in dorsal aspect,
gradually rounded; in posterior aspect, elytral margin does not elevate obliquely toward suture, not in form of angle
with opposite elytron. Abdomen: Intercoxal segment flat, nearly an equilateral triangle, posterior margin straight.
Glabrous segments at apex moderately produced. Segment 7 emarginate at apex. Legs: Protibia slightly concave on
inner surface. Other legs without apparent modification. Genitalia: Males unknown.

Distribution. - (Fig. 167). Guatemala.

Remarks. - Among specimens I collected in the summer of 1974 are more than 200
Hydraena from various localities in Guatemala, Honduras and Mexico, some of which I believe
may be conspecific with H. puncticollis. Although these specimens make up series from many
localities and several different types of streams, all of the series include females only. Further
study is necessary to determine whether absence of males is a sampling artifact or a result of
parthenogenesis. These specimens appear to represent more than one species, based upon
pronotal sculpture and body size, but without males I am unwilling to assign any of them to H.
puncticollis or to describe them as new. A more precise diagnosis of H. puncticollis must await
further material.

39. Hydraena zapatina new species
(Figs. 39C,167)

Type-locality. - Seven miles S. Mazamitla, Jalisco, Mexico.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. My wife Maureen and I collected these specimens, August 15, 1974.

Diagnosis. - Combination of absence of a pronotal scintilla and random (non-serial)
punctures on the elytral disc serve as diagnostic features for this species. The dorsal surface is
very shiny, the pronotum being sparsely punctate and with a dark brown fascia which contrasts

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132

Perkins

well with the surrounding testaceous area. The plaques are well developed, convergent slightly
anteriorly, separated at their bases by about plaque width; each plaque is about 0.50 the length
of the metasternum and as wide as the mesosternal process. The metatibiae of males are
expanded, but very slightly so, at midlength to form a small point, then tapered to the apex to
form a slight indentation; within the indentation there are some stiff spines which contact the
leg.

Description. — Form: Elongate. Size: Holotype 1.46 mm long, 0.62 mm wide. Color: Head with dorsal surface dark
brown; labrum testaceous; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior and posterior
0.25, dark brown in middle 0.50. Elytra brown. Ventral surface dark brown except legs, elytral epipleura, mentum and
inflexed margin of pronotum testaceous. Head: Length 0.20 mm. Width 0.34 mm. Frons moderately punctured, interstices
equal to or slightly greater than puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus finely
microreticulate. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc;
median emargination ended slightly above midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.24/0.12/0.20; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface slightly arcuate, median surface evenly
arcuate; palpomere 4 widest near midlength. Mentum wider than long, surface shining, finely punctulate. Submentum
microreticulate. Genae shining; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with
microreticulation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes 0.25 interocular
distance in width. Thorax: Pronotum length at midline 0.32 mm; maximum width (at approximately midlength) 0.44 mm;
sides margined, denticulate; sides moderately produced at middle, slightly sinuate and convergent to anterior angle,
sinuate and convergent to posterior; anterior border 0.36 mm wide, straight and nearly perpendicular to midline in lateral
0.25, moderately arcuate to rear in middle 0.50; posterior border 0.38 mm wide, slightly arcuate to rear. Posterointernal
foveolae moderately developed; punctures in foveola similar to those on disc. Posteroexternal foveola delimited by very
shallow depression with punctation somewhat closer than that of disc. Interfoveolar depression moderately developed. Area
between external foveolae moderately elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent
shaped, extended across slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not developed,
punctures in this area somewhat closer together than punctures on disc. Disc shining, punctures fine, separated by two to
four times puncture diameter; each puncture with distinctive seta which extended cuticle in dry specimens. Scintilla
absent, although this region very shiny. Prosternum carinate, carina produced anteriorly as very short spine; coxae
separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae
divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively
broad, sides nearly parallel, apex blunt, width at apex 0.66 distance between internal and median carinae. Metasternum
with plaques well developed, straight, convergent moderately from posterior to anterior; plaques 0.50 length of
metasternum in midline; width of each plaque subequal to width of intercoxal process; plaques separated posteriorly by
slightly less than plaque width; plaques flat in cross section. Elytra: Length 0.88 mm. Maximum width (at midlength)
0.64 mm. Surface shining, disc with punctures somewhat serial near suture, randomly arranged on most of disc; most
punctures separated by puncture diameter; punctures each with seta. Explanate margin quite narrow, ended near posterior
0.20. with extremely fine serrations near anterior angles. Elytral apices, in dorsal aspect, gradually rounded; in posterior
aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal
segment flat, longer than wide, posterior margin straight. Glabrous segments at apex moderately produced. Segment 7
slightly emarginate at apex. Legs: Protibia slightly expanded on inner surface near midlength. Metatibiae gradually
enlarged from base to midlength, then gradually tapered to apex, hence widest at midlength; posterior 0.50 with small stiff
spines on inner surface in contact with leg. Genitalia: Aedeagus as illustrated (Fig. 39C)(1 examined).

Natural History. - Refer to H. scopula.

Distribution. - (Fig. 167). Presently known only from the type-locality near Mazamitla in
the state of Jalisco, Mexico.

Etymology. - zapatina , from Spanish in reference to the shoe-shaped process of the
aedeagus (lateral view).

40. Hydraena campbelli new species
(Figs. 37B,167)

Type-locality. - Junction of highways 190 and 195, Chiapas, Mexico.

Type-specimens. - The holotype male and allotype with identical data are deposited in
CNC. J. M. Campbell collected these specimens, June 11, 1969. Paratypes from the same

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133

locality are deposited in CNC (12), USNM (2) and PDP (2).

Diagnosis. - The only totally satisfactory characteristic to distinguish males of this species is
aedeagal form (Fig. 37B), which is quite singular. H. campbelli adults are moderately small,
about 1.45 mm long, with well developed scintilla in both sexes, and males lack a metatibial
brush of hairs. The plaques are oval, occupy about the posterior 0.33 of the metasternum, and
are very slightly convergent anteriorly.

Description. — Form: Elongate. Size: Holotype 1.44 mm long, 0.64 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior and posterior
0.25, dark brown in middle 0.50; sides lighter than middle, Elytra brown. Ventral surface dark brown except legs, elytral
epipleura, mentum and inflexed margin of pronotum brown. Head: Length 0.20 mm. Width 0.38 mm. Frons moderately
punctured, interstices equal to or slightly greater than puncture diameter; surface moderately shining; posterior margin
weakly emarginate to receive scintilla. Frontoclypeal suture straight. Clypeus microreticulate. Labroclypeal suture arcuate
when viewed from above. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.26/0.10/0.16; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface nearly straight in basal 0.33, arcuate in apical 0.66, median surface evenly,
slightly arcuate; palpomere 4 widest slightly past midlength. Mentum wider than long, surface moderately shining, finely
punctulate. Submentum microreticulate. Genae moderately shining; lateral area of each gena with well developed foveola;
posterior ridge nearly imperceptible. Postgena with microreticulation slightly larger than that of submentum. Last five
antennomeres pubescent. Eyes slightly greater than 0.20 interocular distance in width. Thorax: Pronotum length at
midline 0.36 mm; maximum width (at approximately midlength) 0.52 mm; sides margined, denticulate; sides moderately
produced at middle, slightly arcuate and slightly convergent to anterior angle, sinuate and moderately convergent to
posterior; anterior border 0.42 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate
to rear in middle 0.50; posterior border 0.44 mm wide, slightly arcuate to rear. Posterointernal foveolae very slightly
developed; punctures in foveola somewhat closer together than those on disc. Posteroexternal foveola delimited by very
shallow depression with punctation somewhat closer than that of disc. Interfoveolar depression slightly developed. Area
between external foveolae rather noticeably elevated. Anteroexternal foveolae well developed, each foveola somewhat
crescent shaped, extended across slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not
developed, punctures in this area somewhat closer together than punctures on disc. Disc moderately shining, punctures
separated by thin walls near anterior and posterior borders, by 0.50 puncture diameter in middle; punctures without
distinctive seta extended above cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate hind margin.
Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin, median carina; carina
sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median
carina extended to base of intercoxal process; intercoxal process relatively narrow, sides nearly parallel, apex round, width
nearly 0.50 distance between internal and median carinae. Metasternum with plaques moderately developed, somewhat
oval, convergent moderately from posterior to anterior; plaques 0.33 length of metasternum in midline; greatest width of
each plaque slightly less than width of intercoxal process at its midlength; plaques separated posteriorly by approximately
twice plaque width; plaques flat in cross section. Elytra: Length 0.98 mm. Maximum width (at midlength) 0.64 mm.
Surface moderately shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most
punctures round; intervals not elevated, width approximately 0.50 puncture diameter, as are interstices between adjacent
punctures of a row; most punctures with a seta. Explanate margin quite narrow, ended near posterior 0.20, with fine
serrations near anterior angles and apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral
margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly
an equilateral triangle, posterior margin arcuate. Glabrous segments at apex moderately produced. Segment 7 without
emargination at apex. Legs: Protibia slightly arcuate. Metatibia very slightly arcuate. Genitalia: Aedeagus as illustrate
(Fig. 37B)(4 examined).

Distribution. - (Fig. 167). Known only from the type-locality in the mountains of Chiapas,
Mexico.

Etymology. - I am pleased to dedicate this species to J. M. Campbell, who collected the only
known specimens.

41. Hydraena exilipes new species
(Figs. 41D, 167)

Type-locality. - Two miles SW Ciudad Victoria, Tamaulipas, Mexico.

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134

Perkins

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. These specimens plus two male and three female paratypes (PDP) from the same
locality were collected by my wife Maureen and I, July 27, 1974.

Diagnosis. - Distinguished from adults of other species of the leechi Group, which also lack
a scintilla and do not have the anteromedian region of the metasternum elevated, by the small,
oval plaques. The plaques are widely separated, the distance being about equal to four times the
width of a plaque. The pronotum is distinctively produced at the sides, being nearly equally
convergent to the anterior and posterior angles. The legs are exceptionally long and slender.

Description. — Form: Elongate. Size: Holotype 1.74 mm long, 0.74 mm wide. Color: Dorsal surface dark brown,
except border of pronotum slightly lighter; maxillary palpi brown; antennae brown. Ventral surface dark brown except
legs; elytral epipleura, mentum and inflexed margin of pronotum brown. Head: Length 0.24 mm. Width 0.40 mm. Frons
moderately punctured, interstices equal to or slightly less than puncture diameter; setae quite prominent; surface dull.
Clypeus microreticulate. Labroclypeal suture nearly straight across middle in dorsal aspect. Labrum bilobed,
microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary
palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.30/0.14/0.20; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly
straight, median surface arcuate; palpomere 4 widest slightly past midlength. Mentum wider than long, surface dull,
microreticulate. Submentum microreticulate. Genae moderately shining; lateral area of each gena with well developed
foveola; posterior ridge moderately developed at sides, absent from midline. Postgena with microreticulation slightly
smaller than that of submentum. Last five antennomeres pubescent. Eyes 0.50 interocular distance in width. Thorax:
Pronotum length at midline 0.40 mm; maximum width (at approximately midlength) 0.58 mm; sides margined,
denticulate; sides rather markedly produced at middle, slightly arcuate and markedly convergent to anterior angle, sinuate
and convergent to posterior; anterior border 0.42 mm wide, straight and nearly perpendicular to midline in lateral 0.25,
moderately arcuate to rear in middle 0.50; posterior border 0.48 mm wide, slightly arcuate to rear. Posterointernal foveolae
well developed; punctures in foveola similar to those on disc. Posteroexternal foveola well developed. Interfoveolar
depression slightly developed. Area between external foveolae slightly elevated. Anteroexternal foveolae well developed,
each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior region of pronotum.
Transverse foveola slightly developed, with punctures separated by thin walls. Disc dull, punctures moderately large,
generally separated by puncture diameter or less; each puncture with very distinctive seta extended above cuticle in dry
specimens. Scintilla apparently absent; thin, much longer than wide, transparent shelf present in this region, but posterior
margin indistinctly defined. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin,
median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from
anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively narrow, sides
nearly parallel, apex blunt, width at apex 0.66 distance between internal and median carinae. Metasternum with plaques
weakly developed, oval in shape, approximately three times as long as wide, located at posterior 0.17, convergent
moderately from posterior to anterior; plaques 0.17 length of metasternum in midline; plaques separated by about four
times plaque width; plaques flat in cross section. Elytra: Length 1.14 mm. Maximum width (at midlength) 0.74 mm.
Surface dull, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most punctures round;
intervals not elevated, width approximately equal to 0.50 puncture diameter, as are interstices between adjacent punctures
of a row; each puncture with a distinctive seta. Explanate margin rather well developed, ended near apices, with serrations
near anterior angles and apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin not
elevated obliquely toward suture, not in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than
long, posterior margin weakly arcuate. Glabrous segments at apex moderately produced. Segment 7 somewhat conical;
apex slightly emarginate. Legs: Profemur with tubercle on inner surface near basal 0.33. Protibia expanded on inner
surface near apical 0.33, lateral surface straight. Metafemur relatively thin. Metatibia straight, gradually enlarged from
base to apex, relatively long and thin. Genitalia: Aedeagus as illustrated (Fig. 41D)(3 examined).

Natural History. - These beetles were collected at the sand-gravel margin of a semi-arid
stream. Limnebius angustulus adults were also found at this locality.

Distribution. - (Fig. 167). Presently known only from the type-locality near Ciudad Victoria
in the state of Tamaulipas, Mexico.

Etymology. - Latin, exilis (thin) plus ipes (foot). This species has very slender legs.

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Figs. 40A - F, Hydraena ozarkensis. (A) head of <3, dorsal aspect. (B) head of 9, dorsal aspect. (C) occipital ridges of 6.
(D) 6 pronotum. (E) metasternum. (F) prosternum and venter of head.

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42. Hydraena ozarkensis new species
(Figs. 40A-F,41 A-B,42B, 1 67)

Type-locality. - Rush Creek, 2 miles E. Jane, McDonald Co., Missouri.

Type-specimens. - The holotype male and allotype with same locality data are deposited in
USNM. I collected these specimens, August 8, 1972. Paratypes (61) are listed in the appendix.

Diagnosis. - Random, non-serial arrangement of punctures on the elytral disc plus small
size, about 1.36 mm long, serve to readily distinguish H. ozarkensis adults from all other
members of the leechi Group which have a pronotal scintilla, except H. maureenae. From this
latter species H. ozarkensis is distinguished by broader form (with the sides of the elytra being
rounded, not parallel), distribution (Fig. 42B), and aedeagus (Figs. 41 A-C).

Description. — Form: Elongate-oval. Size: Holotype 1.36 mm long, 0.60 mm wide. Color: Head with dorsal surface
dark brown, nearly black; labrum dark brown; maxillary palpi and antennae testaceous. Pronotum testaceous at anterior
and posterior 0.33, reddish brown in center 0.33; elevated areas between external foveolae somewhat lighter than disc.
Elytra brown. Ventral surface brown except legs, elytral epipleura, and inflexed margin of pronotum, light brown. Head:
Length 0.20 mm. Width 0.36 mm. Frons moderately punctured, interstices equal to or slightly greater than puncture
diameter; surface shining; Frontoclypeal suture straight. Clypeus microreticulate. Labroclypeal suture nearly straight
across middle in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.24/0.12/0.20; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface nearly straight in basal 0.33, arcuate in apical 0.66, median surface arcuate;
palpomere 4 widest slightly past midlength. Mentum wider than long, microreticulate. Submentum microreticulate. Genae
shining; lateral area of each gena with well developed foveola; posterior ridge nearly imperceptible. Postgena with
microreticulation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly greater than
0.20 interocular distance in width. Thorax: Pronotum length at midline 0.36 mm; maximum width (at approximately
midlength) 0.46 mm; sides margined, denticulate; sides moderately produced at middle, very slightly sinuate and slightly
convergent to anterior angle, sinuate and convergent to posterior; anterior border 0.38 mm wide, straight and nearly
perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.40 mm wide, slightly
arcuate to rear. Posterointernal foveolae well developed; punctures in foveola closer together than those on disc.
Posteroexternal well developed. Interfoveolar depression moderately developed. Area between external foveolae
moderately elevated. Anteroexternal foveolae well developed, each foveola some what crescent shaped, extended across
slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not developed, punctures in this area
somewhat closer together than punctures on disc. Disc shining, punctures well impressed, separated by puncture diameter;
many punctures with seta extended above cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate
hind margin. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated from median carina by
thin shelf; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to
posterior; median carina extended to base of intercoxal process; intercoxal process relatively broad, sides tapered, apex
blunt, width at apex nearly 0.66 distance between internal and median carinae. Metasternum with plaques well developed,
somewhat triangular, convergent moderately from posterior to anterior; plaques 0.40 length of metasternum in midline;
greatest width of each plaque slightly less than width of intercoxal process at its apex; plaques separated posteriorly by
approximately twice plaque width; plaques flat in cross section (Fig. 40E). Elytra: Length 0.88 mm. Maximum width (at
midlength) 0.60 mm. Surface shining, disc with well impressed randomly arranged puncture; sutural and second row of
punctures somewhat serial, other punctures randomly arranged; punctures rather well impressed; most punctures with
seta. Explanate margin rather well developed, ended near posterior 0.10, with extremely fine serrations near anterior
angles and apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely
toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin
arcuate. Glabrous segments at apex moderately produced. Segment 7 without emargination at apex. Legs: Protibia very
slightly excavate on inner surface in apical 0.33. Metatibia nearly parallel in apical 0.66. Genitalia: Aedeagus as
illustrated (Figs. 41 A-B) (20 examined).

Variation. - Males from Indiana have the apex of the aedeagus shaped slightly differently
from that of the holotype. I have illustrated an example (Fig. 40B).

Natural History. - The stream at the type-locality is very small, the beetles being taken
from the sand at the margin. Consocies included Limnebius ozapalachicus and Paracymus sp.
H.S. Dybas has collected adults during their dispersal flight, between 4:45 and 5:15 pm,
August 14, 1971.

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137

Figs. 41 A - D, Aedeagi of Hydraena species. (A) H. ozarkensis, holotype. (B) H. ozarkensis, variant from Monroe
County, Indiana. (C) H. maureenae , holotype. (D) H. exilipes , holotype.

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Distribution. - (Figs. 42B,167). Ozark Plateau of Missouri, Tennessee, Indiana and
Oklahoma.

Etymology. - Latin, ozarkensis, in reference to the geographical distribution.

43. Hydraena maureenae new species
(Figs. 41C,42B, 167)

Type-locality. - Twelve miles S. Williamsville, Bath County, Virginia.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. I collected these specimens, October 6, 1973. The following seven paratypes (PDP)
were taken at the same locality: 1 female, April 21, 1974; 1 male, June 4, 1974; 1 male, 4
females, April 21, 1975.

Diagnosis. - H. maureenae adults are readily distinguished from all other members of the
lee chi Group which have a scintilla, except H. ozarkensis , by the random, non-serial
arrangement of the punctures on the elytral disc plus its small size, about 1.46 mm long. From
H. ozarkensis adults, those of H. maureenae are distinguished by slightly greater length,
narrower body form, distribution (Fig. 42B), and aedeagus (Figs. 41 A-C).

Description. — Form: Elongate. Size: Holotype 1.46 mm long, 0.58 mm wide. Color: head with dorsal surface and
labrum dark brown; maxillary palpi and antennae testaceous. Pronotum testaceous at anterior and posterior 0.25, reddish
brown in center 0.33; elevated areas between external foveolae somewhat lighter than disc. Elytra testaceous, slightly
darker than testaceous areas of pronotum. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of
pronotum testaceous. Head: Length 0.20 mm. Width 0.38 mm. Frons moderately punctured, interstices equal to or slightly
greater than puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus finely microreticulate.
Labroclypeal suture nearly straight across middle in dorsal aspect. Labrum bilobed, microreticulate, each lobe
symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with following
lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.28/0.12/0.20; palpomere 2 bent outward at approximately
midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly straight in basal
0.33; arcuate in apical 0.66, median surface similarly shaped; palpomere 4 widest at apical 0.33. Mentum wider than long,
surface moderately shining, finely punctulate. Submentum microreticulate. Genae shining; lateral area of each gena with
well developed foveola; posterior ridge nearly imperceptible. Postgena with microreticulation slightly larger than that of
submentum. Last five antennomeres pubescent. Eyes slightly less than 0.17 interocular distance in width. Thorax:
Pronotum length at midline 0.36 mm; maximum width (at approximately midlength) 0.50 mm; sides margined,
denticulate; sides well produced at middle, very weakly sinuate and convergent to anterior angle, sinuate and convergent to
posterior; anterior border 0.40 mm. wide, straight and nearly perpendicular to midline in lateral 0.20, moderately arcuate
to rear in middle 0.60; posterior border 0.40 mm wide, slightly arcuate to rear. Posterointernal foveolae well developed;
punctures in foveola closer together than those on disc. Posteroexternal foveolae well developed. Interfoveolar depression
well developed. Area between external foveolae clearly elevated. Anteroexternal foveolae well developed, each foveola
somewhat crescent shaped, occupying slightly less than 0.33 width of anterior region of pronotum. Transverse foveola
slightly developed, punctures separated by thin walls. Disc shining, punctures well impressed, separated by 0.50 puncture
diameter near anterior and posterior borders, by puncture diameter in middle; some punctures with seta extended above
cuticle in dry specimens. Scintilla distinct, flat, impunctate shelf with arcuate anterior and posterior margins. Prosternum
carinate, carina produced anteriorly as very short spine; coxae separated by thin, median carina; carina sinuate line in
lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior median carina
extended to base of intercoxal process; intercoxal process relatively broad, sides nearly parallel, apex blunt, width at apex
nearly 0.66 distance between internal and median carinae. Metasternum with plaques well developed, triangular, medial
margins parallel; plaques 0.40 length of metasternum in midline; greatest width of each plaque 0.66 width of intercoxal
process at its midlength; plaques separated posteriorly by approximately twice plaque width; plaques flat in cross section.
Elytra: Length 0.94 mm. Maximum width (at midlength) 0.58 mm. Surface shining, disc with sutural, second, third and
fourth rows of punctures somewhat serial, other punctures randomly arranged; most punctures with seta. Explanate
margin narrow, ended near posterior 0.10; with extremely fine serrations near anterior angles and apices. Elytral apices, in
dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with
opposite elytron. Abdomen : Intercoxal segment flat, width twice length; anterior angle rounded; posterior margin arcuate.
Glabrous segments at apex moderately produced. Segment 7 without emargination at apex. Legs: Protibia with arcuate
lateral surface, nearly straight medial surface. Metatibia very slightly wider at midlength than at apex. Genitalia:
Aedeagus as illustrated (Fig. 41C)(3 examined).

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139

Figs. 42A - B, Geographical distributions of Hydraena species. (A) H. cuspidicollis • , H. prieto ★ and H. mexicana
A (B) H. ozarkensis • , H. maureenae ★ , H. punctata A and H. youngi ■ .

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Natural History. - The substratum at the margin of the small stream at the type-locality
(Fig. 193B) consisted of small to moderately large, smooth slate fragments. Consocies included
a very large population of Limnebius ozapalachicus plus a few specimens of L. discolor and L.
richmondi.

Distribution. - (Figs. 42B,167). Presently known only from the type-locality in the
Appalachian Mountains of Virginia.

Etymology. - I am very pleased to dedicate this species to my wife Maureen Ellen, who has
assisted me in collecting aquatic Coleoptera throughout North and Central America, and who
has been a constant source of encouragement during the course of this study.

The particeps Subgroup

Members of the particeps Subgroup lack a pronotal scintilla and do not have the
anteromedial region of the metasternum elevated to form a ridge (cf. the argutipes Subgroup).
Adults of most of the nine species presently known for this subgroup are quite small.

Geographically, this group ranges from Brazil northward through Central America and the
Antilles to southern Mexico and the eastern United States as far north as Massachusetts.

44. Hydraena orcula new species
(Figs. 43D,168)

Type-locality. - Ria Chim, Mosquito, Goias, Brazil.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. Harley P. Brown collected these specimens, June 17, 1968.

Diagnosis. - Small size, about 1.16 mm long, and plaque shape serve to distinguish H.
orcula adults from adults of other species of the leechi Group which lack a scintilla and have
well developed posterointernal foveolae. The plaques are narrow, about 0.33 the length of the
metasternum; the distance separating the plaques being four times the width of a plaque, and
equal to the length of a plaque. The aedeagus (Fig. 43D) is unique.

Description. — Form: Ovate. Size: Holotype 1.16 mm long, 0.50 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior and posterior
0.25, dark brown in center 0.50; sides slightly lighter than center. Elytra brown, approximately midway in color between
extremes of pronotum. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum
testaceous. Head: Length 0.16 mm. Width 0.32 mm. Frons moderately punctured, interstices equal to or slightly greater
than puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus microreticulate. Labroclypeal suture
arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpi missing from holotype, allotype with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.22/0.08/0.16; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral and median surfaces slightly arcuate; palpomere 4
widest at apical 0.33. Mentum wider than long, surface moderately shining, microreticulate. Submentum microreticulate.
Genae shining; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with
microreticulation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly less than 0.25
interocular distance in width. Thorax: Pronotum length at midline 0.28 mm; maximum width (at approximately
midlength) 0.40 mm; sides margined, denticulate; sides relatively slightly produced at middle, slightly arcuate and slightly
convergent to anterior angle, slightly sinuate and slightly convergent to posterior; anterior border 0.34 mm wide, straight
and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.36 mm
wide, slightly arcuate to rear. Posterointernal foveolae moderately developed; punctures in foveola closer together than
those on disc, some confluent. Posteroexternal foveola delimited by very shallow depression with punctation somewhat
closer than that of disc. Interfoveolar depression slightly developed. Area between external foveolae weakly elevated.
Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33

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141

width of anterior region of pronotum. Transverse foveola slightly developed, with punctures closer together than
punctures on disc. Disc shining, punctures moderately fine, separated by 0.25 puncture diameter near anterior and
posterior borders, by puncture diameter in middle; punctures each with distinctive seta extended above cuticle in dry
specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by
thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent
from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively narrow,
sides parallel, apex rounded, width 0.66 distance between internal and median carinae. Metasternum with plaques well
developed, somewhat triangular, median margins nearly parallel; plaques 0.33 length of metasternum in midline;
plaques separated posteriorly by approximately plaque length, which is equal to four times plaque width; plaques flat in
cross section. Elytra: Length 1.16 mm. Maximum width (at midlength) 0.50 mm. Surface shining, disc with 10 rows of
punctures between suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width
approximately equal to puncture diameter, as are interstices between adjacent punctures of a row; punctures each with
seta. Explanate margin quite narrow, ending near posterior 0.20, with extremely fine serrations at anterior angles.
Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated very slightly, obliquely
toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly an equilateral triangle,
posterior margin weakly arcuate. Glabrous segments at apex weakly produced. Apical segment without emargination at
apex. Legs: Without apparent modification. Genitalia: Aedeagus as illustrated (Fig. 43D)(1 examined).

Distribution. - (Fig. 168). Known only from the type-locality in the state of Goias, Brazil.
Etymology. - Latin, orca (whale) plus ula (diminutive). Named in reference to the shape of
the aedeagus.

45. Hydraena sahlbergi d’Orchymont
(Fig 168)

Hydraena sahlbergi d’Orchymont, 1923:40 (holotype female in HM; type-locality: Santa Rita, Minas Gerais, Brazil).

Diagnosis. - Readily distinguished from other members of the leechi Group found in the

same geographical area, (mountains of southeastern Brazil), by absence of a pronotal scintilla.
Refer to the diagnosis of H. spangleri for additional comments.

Description. — Form: Elongate. Size: Holotype 1 .57 mm long, 0.68 mm wide. Color: Head with dorsal surface dark
brown; labrum brown; maxillary palpi and antennae testaceous. Pronotum dark brown except testaceous band at anterior
and posterior borders; width of band about 0.17 length of pronotum. Elytra brown. Ventral surface brown except legs,
elytral epipleura and indexed margin of pronotum testaceous. Head: Length 0.27 mm. Width 0.39 mm. Frons shiny,
moderately punctate, interstices one-two times puncture diameter. Frontoclypeal suture straight. Clypeus microreticulate.
Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median
emargination ended at about midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4
respectively: 0.26/0.09/0.19; palpomere 2 bent outward at about midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface nearly straight, medial surface arcuate, widest near midlength. Mentum wider
than long, surface moderately shining, microreticulate. Submentum microreticulation similar to mentum. Genae shining,
finely punctulate; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with
microreticulation similar to that of submentum. Last five antennomeres pubescent. Eyes 0.17 interocular distance in
width. Thorax: Pronotum length at midline 0.41 mm; maximum width (at approximately midlength) 0.51 mm; sides
margined, denticulate; sides relatively slightly produced at middle, nearly straight and convergent to anterior angle, very
slightly sinuate and convergent to posterior; anterior border 0.44 mm wide, straight and nearly perpendicular to midline in
lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.48 mm wide, slightly arcuate to rear.
Posterointernal foveolae weakly developed; punctures in foveola closer together than those on disc. Posteroexternal foveola
delimited by very shallow depression with punctation somewhat closer than that of disc. Interfoveolar depression absent.
Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extneded across slightly less than 0.33
width of anterior region of pronotum. Transverse foveola not developed, punctures in this area somewhat closer together
than punctures on disc. Disc dull, punctures moderately sized, very deeply impressed, separated by narrow walls near
anterior and posterior borders, and by 0.50 puncture diameter in middle; most punctures without distinctive seta extended
above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae
separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae
divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively
narrow, sides nearly parallel, apex blunt, width at apex 0.66 distance between internal and median carinae. Metasternum
with plaques well developed, slightly arcuate, convergent moderately from posterior to anterior; each plaque tapered from
posterior to anterior; plaques 0.50 length of metasternum in midline; greatest width of each plaque 0.66 width of intercoxal
process at its midlength; plaques separated posteriorly by approximately three times plaque width; plaques flat in cross
section. Elytra: Length 1.02 mm. Maximum width (at midlength) 0.68 mm. Surface shining, disc with 10 rows of

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markedly impressed punctures between suture and humeral callus; puncture shape irregular; intervals not elevated,
width approximately equal to 0.25 puncture diameter, somewhat irregular due to displacement by punctures; interstices
between adjacent punctures of row approximately 0.25 puncture diameter; each puncture with seta. Explanate margin
quite narrow, ended near posterior 0.20 with extremely fine, well separated serrations along entire margin. Elytral
apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form
of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Legs:
Without apparent modification. Genitalia: Males unknown.

Distribution. - (Fig. 168). Known only from the type-locality, Santa Rita, Minas Gerais,
Brazil.

Remarks. - Other than the holotype I have seen only a single female from the type-locality
(BMNH).

46. Hydraena particeps new species
(Figs. 43A-B,59,168)

Type-locality. - Calabozo, 32 km. SW, Guarico, Venezuela.

Type-specimens. - The holotype male, which was collected by Paul J. Spangler, February
11, 1969, is deposited in USNM. The allotype, from Albrook Forest Site, Canal Zone, Panama,
is also deposited in USNM. Paratypes (22) are listed in the appendix.

Diagnosis. - The plaques are moderately long and narrow, separated by about four times
the width of a plaque. Additionally, the pronotum lacks a scintilla and has well developed
posterointernal foveolae, and the metasternum does not have the anteromedial region elevated.
These features, plus the distinctive aedeagus (Figs. 43A-B), serve as the diagnostic
characteristices for H. particeps.

Description. — Form: Elongate. Size: Holotype 1.40 mm long, 0.48 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior and posterior
0.25, dark brown in center 0.50; sides slightly lighter than center. Elytra brown, approximately midway in color between
extremes of pronotum. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum brown.
Head: Length 0.20 mm. Width 0.38 mm. Frons moderately punctured, interstices equal to or slightly less than puncture
diameter; surface moderately shining; posterior margin very slightly emarginate in midline. Frontoclypeal suture straight.
Clypeus microreticulate. Labroclypeal suture nearly straight across middle in dorsal aspect. Labrum bilobed,
microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary
palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.26/0.10/0.18; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral and median
surfaces slightly arcuate, widest near midlength. Mentum wider than long, surface moderately shining, microreticulate.
Submentum microreticulate. Genae shining; lateral area of each gena with well developed foveola; posterior ridge absent.
Postgena with microreticulation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes 0.25
interocular distance in width. Thorax: Pronotum length at midline 0.38 mm; maximum width (at approximately
midlength) 0.50 mm; sides margined, denticulate; sides moderately produced at middle, slightly sinuate and convergent to
anterior angle, slightly sinuate and convergent to posterior; anterior border 0.42 mm wide, straight and nearly
perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.46 mm wide, slightly
arcuate to rear. Posterointernal foveolae moderately developed; punctures in foveola similar to those on disc.
Posteroexternal foveola delimited by very shallow depression with punctation somewhat closer than that of disc.
Interfoveolar depression weakly developed. Area between external foveolae nearly flat. Anteroexternal foveolae well
developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior region of
pronotum. Transverse foveola weakly developed, with punctures somewhat closer together than punctures on disc. Disc
shining, punctures fine, separated by 0.50 puncture diameter near anterior and posterior borders, by puncture diameter in
middle; punctures each with distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum
carinate, carina produced anteriorly into very short spine; coxae separated by a thin, median carina; carina sinuate line in
lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior ; median carina
extended to base of intercoxal process; intercoxal process relatively narrow, sides nearly parallel, apex blunt, width at apex
0.50 distance between internal and median carinae. Metasternum with plaques well developed, straight, convergent
moderately from posterior to anterior; plaques 0.36 length of metasternum in midline: width of each plaque 0.66 width of
intercoxal process; plaques separated posteriorly by approximately four times plaque width; plaques flat in cross section.
Elytra: Length 1.00 mm. Maximum width (at midlength) 0.48 mm. Surface shining, disc with 10 rows of punctures

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143

Figs. 43 A - D, Aedeagi of Hydraena species. (A) H. particeps , holotype. (B) H. particeps variant from Honduras. (C) H.
decui , holotype. (D) H. orcula, holotype.

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between suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width
approximately equal to puncture diameter, interstices between adjacent punctures of a row slightly smaller; punctures
each with seta. Explanate margin quite narrow, ended near posterior 0.20, with extremely fine serrations near apices.
Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture,
in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin arcuate.
Glabrous segments at apex moderately produced. Apical segment without emargination at apex. Legs: Protibia with
slight emargination on inner surface near midlength. Other legs without apparent modification. Genitalia: Aedeagus as
illustrated (Figs. 43A-B) (13 examined).

Natural History . - The notation, “pocket of damp leaves in dry streambed”, is the only
microhabitat information presently available.

Distribution. - (Figs. 59,168). From Honduras south to Panama and east through
Venezuela to Trinidad and Grenada.

Variation. - The single male I have seen from Honduras, the northernmost locality known to
date, has an aedeagus (Fig. 43B) of slightly different form than the other males studied
(Fig. 43 A). Externally this specimen is noticably more densely punctate on the pronotum, but
agrees quite well in other respects. This specimen might represent another species, but I prefer
to treat it as an aedeagal morph until more material from Central America becomes available
for study.

Etymology. - Latin, particeps (comrade, partner, sharing). Named in reference to the
phylogenetic relationship of this species to H. decui, as indicated by the aedeagus.

47. Hydraena decui Spangler
(Figs. 43C,168)

Hydraena decui Spangler, 1980:329 (holotype male in USNM; type-locality: Arroyo de la Poa, Sabanilla, Cuba).

Diagnosis. - Transverse pronotum, widely separated plaques and aedeagal form serve as
diagnostic characteristics for adults of this small, rather broad Cuban species.

Description. — Form: Ovate, moderately broad. Size: Holotype 1.18 mm long, 0.52 mm wide. Color: Entirely
testaceous except for dark brown frons and light brown, indistinct pronotal macula. Head: Length 0.18 mm, width
0.30 mm. Frons finely, moderately densely punctate, interstices shiny. Frontoclypeal suture slightly arcuate. Clypeus
finely punctulate, faintly microreticulate laterally. Labroclypeal suture straight. Labrum microreticulate, bilobed, median
emargination ending near midlength. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4 respectively:
0.20/0.08/0. 1 5; palpomere 4 unusually slender, widest near midlength, outer edge straight. Mentum wider than long, dull,
microreticulate. Submentum microreticulate. Genae shiny, foveolate laterally. Postgena microreticulate. Thorax:
Pronotum length at midline 0.29 mm; maximum width (at midlength) 0.43 mm; sides margined, very finely denticulate,
distinctly produced at middle, slightly arcuate and convergent to anterior angles, sinuate and convergent to posterior
angles; anterior border 0.34 mm wide, straight and perpendicular to midline in lateral 0.25, slightly arcuate to rear in
posterior 0.50; posterior border 0.35 mm wide, very slightly arcuate to rear. Posterointernal and posteroexternal foveolae
absent. Anteroexternal foveolae well developed, each somewhat crescent shaped, extended across slightly less than 0.33
width of anterior region of pronotum. Transverse foveola absent. Disc shiny, finely moderately densely punctate, punctures
separated by one-two times puncture diameter; punctures without apparent setae. Scintilla absent. Prosternum carinate;
carina between coxae, sinuate in lateral view. Mesosternum with internal and external carinae divergent from anterior to
posterior; median carina extended to base of intercoxal process; intercoxal process of moderate width, apex blunt, width at
apex 0.50 distance between internal and median carinae. Metasternum with plaques small, narrow, length about equal to
width of intercoxal process, width 0.50 length; plaques separated by about five times plaque width. Elytra: Length
0.73 mm. Maximum width (at midlength) 0.52 mm. Disc shiny, with 10 rows of small, close-set punctures between suture
and humeral callus; intervals not elevated, width less than puncture diameter, as are interstices between punctures of a
row; most punctures with very fine seta. Explanate margin well developed, ending near posterior 0.20, finely serrate.
Elytral apices very slightly dehiscent, in posterior aspect elytral margin elevated obliquely toward suture, in form of angle
with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Legs: Profemur with
low carina on inner surface near base. Protibia slightly arcuate. Other legs moderately slender, unmodified. Genitalia:
Aedeagus as illustrated (Fig. 43C)(1 examined).

Distribution. - (Fig. 168). Cuba.

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145

48. Hydraena guadelupensis d’Orchymont
(Figs. 44D,59,168)

Hydraena guadelupensis d’Orchymont, 1923:37 (holotype male in 1SNB; type-locality: Guadeloupe). - d’Orchymont,

1945a: 1-4.

Diagnosis. - Small size, about 1.30 mm long, and the elytral apices which, when viewed
posteriorly, do not turn upwards toward the suture serve to distintuish H. guadelupensis adults
from other members of the leechi Group occupying the same geographical area (Fig. 59). Refer
to the diagnosis of H. spangleri for further comments.

Description. — Form: Elongate-oval. Size: Holotype 1.30 mm long, 0.55 mm wide. Color: Head with dorsal surface
dark brown; labrum brown; maxillary palpi and antennae testaceous. Pronotum testaceous except for transverse,
rectangular brown (lighter than head) macula on disc approximately 0.18 mm long, 0.30 mm wide; macula at borders
blended into surrounding testaceous areas. Elytra same color as pronotal macula. Ventral surface dark brown except legs,
plaques, elytral epipleurae and inflexed margin of pronotum brown. Head: Length 0.19 mm. Width 0.32 mm. Frons finely
and sparsely punctate, interstices one to three times puncture diameter; surface shining. Frontoclypeal suture arcuate to
rear. Clypeus microreticulate. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe
symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with following
lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.23/0.10/0.16; palpomere 2 bent outward at approximately
midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly straight in basal
0.33, arcuate in apical 0.66, median surface arcuate; apical segment widest near distal 0.33. Mentum wider than long,
surface moderately shining, microreticulate. Submentum microreticulation similar to mentum. Genae shining; lateral area
of each gena with a well developed foveola; posterior ridge absent. Postgena with microreticulation similar to that of
submentum. Last five antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width. Thorax:
Pronotum length at midline 0.32 mm; maximum width (at approximately midlength) 0.55 mm; sides margined,
denticulate; sides moderately produced at middle, arcuate and convergent to anterior angle, sinuate and convergent to
posterior; anterior border 0.37 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate
to rear in middle 0.50; posterior border 0.40 mm wide, slightly arcuate to rear. Posterointernal foveolae moderately
devloped; punctures in foveola similar to those on disc. Posteroexternal foveola delimited by very shallow depression with
punctation somewhat closer than that of disc. Interfoveolar depression weakly developed. Area between external foveolae
not elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across less than
0.33 width of anterior region of pronotum. Transverse foveola not developed, punctures in this area somewhat closer
together than punctures on disc. Disc shining, punctures fine, separated by twice puncture diameter; most punctures with
seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very
short spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and
external carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal
process relatively narrow, sides nearly parallel; apex blunt, width at apex 0.50 distance between internal and median
carinae. Metasternum with plaques well developed, straight, convergent moderately from posterior to anterior; plaques
0.43 length of metasternum in midline; width of each plaque subequal to width of intercoxal process at its midlength;
plaques separated posteriorly by approximately twice plaque width; plaques separated anteriorly by 1.50 plaque width;
plaques flat in cross section. Elytra: Length 0.83 mm. Maximum width (at midlength) 0.55 mm. Surface shining, disc with
10 rows of punctures between suture and humeral callus, rows quite Regular; most punctures round; intervals not elevated,
width approximately equal to puncture diameter, as are interstices between adjacent punctures of a row; most punctures
without perceptible seta. Explanate margin quite narrow, ended near posterior 0.20, with extremely fine, well separated
serrations along entire margin; serrations slightly closer near apices. Elytral apices, in dorsal aspect, gradually rounded; in
posterior aspect, elytral margin not elevated obliquely toward suture, not in form of angle with opposite elytron. Abdomen:
Intercoxal segment flat, wider than long, posterior margin straight. Glabrous segments at apex only moderately produced.
Segment 7 without emargination at apex. Legs: Protibia slightly arcuate; other legs without apparent modification.
Genitalia: Aedeagus as illustrated (Fig. 44D)(21 examined).

Variation. - The aedeagus of the single male I have seen from Costa Rica has the apex
slightly different from that of other specimens (Fig. 44D). Length and general proportions of
this aedeagus are virtually identical to aedeagi of specimens from Guadeloupe and Jamaica.
Externally, this beetle is very slightly smoother than those from the remainder of the
distribution. I have examined 59 specimens (see appendix).

Natural History. - The only microhabitat notations present in the locality data are “sifted
from swamp litter” and “ex small pool in narrow gully”.

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Distribution. - (Figs. 59,168). Guadeloupe, Jamaica and Costa Rica.

49. Hydraena spangleri new species
(Figs. 44C,56B,168)

Type-locality. - Plummer’s Island, Montgomery County, Maryland.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. Paul J. Spangler collected these specimens, November 1, 1960. Paratypes (150) are
listed in the appendix.

Diagnosis. - Small size, about 1.30 mm long, and lack of a distinct pronotal scintilla readily
distinguish adults of H. spangleri from those of all other species of the leechi Group which
occupy the same geographical area (Fig. 56B). H. spangleri adults are externally very similar
to those of the putative sister-species, H. guadelupensis from the Antilles and Costa Rica. H.
guadelupensis adults are slightly narrower, generally less densely punctate and do not have the
elytral margins turned upwards toward the suture, in posterior aspect. Aedeagi of males of the
two species (Figs. 44C-D) are distinct, but obviously markedly similar. Adults of these two
species are similar to those of H. sahlbergi in that all three species have (1) serial elytral
punctures, (2) lack a median metasternal ridge posterior to the mesosternal process, and (3)
have the metasternal plaques convergent anteriorly. H. sahlbergi adults however, are larger
(about 1.57 mm long), with narrower elytral intervals and are known only from southeastern
Brazil.

Description. — Form: Elongate-oval. Size: Holotype 1.30 mm long, 0.55 mm wide. Color: Head with dorsal surface
dark brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior and
posterior 0.25, brown in middle 0.50, sides slightly lighter than center. Elytra brown. Ventral surface dark brown except
legs, elytral epipleura, apex of abdomen and inflexed margin of pronotum, testaceous. Head: Length 0.16 mm. Width
0.32 mm. Frons moderately punctate, interstices equal to or slightly greater than puncture diameter; surface shining.
Frontoclypeal suture straight. Clypeus microreticulate. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed,
microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary
palpus with following lengths (mm) of palpomeres 2, 3, and 4, respectively: 0.20/0.08/0.16; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral and medial
surfaces slightly arcuate. Mentum longer than wide, surface moderately shining, finely punctulate. Submentum
microreticulate. Genae shining; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with
microreticulation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly greater than
0.25 interocular distance in width. Thorax: Pronotum length at midline 0.32 mm; maximum width (at approximately
midlength) 0.46 mm; sides margined, denticulate; sides moderately produced at middle, slightly arcuate and slightly
convergent to anterior angle, sinuate and convergent to posterior; anterior border 0.36 mm wide, straight and nearly
perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.40 mm wide, slightly
arcuate to rear. Posterointernal foveolae moderately developed; punctures in foveola closer together than those on disc.
Posteroexternal foveola delimited by very shallow depression with punctation somewhat closer than that of disc.
Interfoveolar depression slightly developed. Area between external foveolae nearly flat. Anteroexternal foveolae well
developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior region of
pronotum. Transverse foveola slightly developed, with punctures separated by thin walls. Disc shining, punctures fine and
close, separated by less than puncture diameter; most punctures with seta extended above cuticle in dry specimens.
Scintilla absent, represented by narrow, reflective, impunctate area. Prosternum carinate, carina produced anteriorly as
very short spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal
and external carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal
process relatively narrow, sides parallel, apex somewhat rounded, width near apex 0.50 distance between internal and
median carinae. Metasternum with plaques well developed, straight, convergent from posterior to anterior; plaques 0.50
length of metasternum in midline; plaques separated posteriorly by approximately twice plaque width; plaques separated
anteriorly by approximately plaque width; plaques flat in cross section. Elytra: Length 0.86 mm. Maximum width (at
midlength) 0.58 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite
regular; most punctures round; intervals not elevated, width approximately equal to puncture diameter; interstices between
adjacent punctures of row 0.50 puncture diameter; punctures each with seta. Explanate margin quite narrow, ended near
posterior 0.20, with extremely fine serrations near anterior angles and apices. Elytral apices, in dorsal aspect, gradually

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147

Figs. 44A - D, Aedeagi of Hydraena holotypes. (A) H. oblio. (B) H. punctata. (C) H. spangleri. (D) H. guadelupensis
(inset: specimen from Costa Rica).

rounded; in posterior aspect, elytral margin not elevated obliquely toward suture, not in form of angle with opposite
elytron. Abdomen: Intercoxal segment flat, nearly an equilateral triangle, posterior margin very weakly arcuate.
Glabrous segments at apex moderately produced. Segment 7 without emargination at apex. Legs: Protibia arcuate,
enlarged gradually from base to apex. Metatibia straight, gradually enlarged from base to apex. Genitalia: Aedeagus as
illustrated (Fig. 44C)(72 examined).

Natural History. - H. spangleri appears to be primarily a pond species. Habitat notations in
the locality data include “pothole”, “pond”, “debris at swamp edge”, “hardwood hammock”,
“Palmetto-Mahogany swamp”, “under water hyacinth”, “grassy compost mixed with Cypress

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Perkins

needles”, “litter in sinkhole”, and “sphagnum”. Adults of H. spangleri are frequently collected
in association with H. atlantica adults in Maryland and with those of H. marginicollis in
Florida. In one locality record provided by W. Suter, adults were found living in sphagnum with
H. ancylis adults in Hardin County, Texas.

Distribution. - (Figs. 56B,168). Generally found in, but not restricted to, coastal areas;
eastern United States, Maryland to Texas.

Etymology. - It is with pleasure that I dedicate this species to Paul J. Spangler in
recognition of his significant contributions to the knowledge of aquatic Coleoptera.

50. Hydraena punctata LeConte
(Figs. 42B,44B,168)

Hydraena punctata LeConte, 1855:362 (holotype male in MCZ; type-locality: Pennsylvania).

Hydraena needhami d’Orchymont, 1929:79 (holotype female in ISNB; type-locality: Ithaca, New York; new synonomy).

D’Orchymont’s type-specimen does not differ significantly from LeConte’s type-specimen.
Refer to the remarks section for additional comments.

Diagnosis. - Among those species of the leechi Group whose adults lack a scintilla, lack a
median, anterior ridge on the metasternum, and have the elytral punctures in series, H.
punctata adults are distinguished by moderately elongate, widely separated plaques. The
plaques converge slightly with one another anteriorly, being separated anteriorly by about four
times the width of a plaque. H. punctata is distinct also in its distribution, being the only
member of the leechi Group living in northeastern United States (Fig. 42B).

Description. — Form: Elongate. Size: Holotype 1.48 mm long, 0.70 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi testaceous except apices brown; antennae testaceous. Pronotum testaceous
except for transverse, rectangular, brown (lighter than head) macula on disc which occupies approximately middle 0.56 of
pronotum; macula lighter near sides of pronotum and blended into anterior and posterior testaceous areas. Elytra same
color as testaceous areas of pronotum. Ventral surface dark brown except legs, elytral epipleura and indexed margin of
pronotum brown. Head: Length 0.20 mm. Width 0.40 mm. Frons punctation coarse, deeply impressed, interstices equal to
puncture diameter or less; surface moderately shining. Frontoclypeal suture straight. Clypeus microreticulate.
Labroclypeal suture arcuate when viewed from above. Labrum bilobed, microreticulate, each lobe symmetrical arc;
median emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.28/0.10/0.20; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly straight in basal 0.33, arcuate in
apical 0.66, median surface arcuate; apical segment widest near distal 0.33. Mentum wider than long, surface moderately
shining, microreticulate laterally. Submentum microreticulate. Genae shining, finely microreticulate, lateral area of each
gena with well geveloped foveola; posterior ridge absent. Postgena with microreticulation similar to that of submentum.
Last five antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width. Thorax: Pronotum length at
midline 0.40 mm; maximum width (at approximately midlength) 0.52 mm; sides margined, denticulate; sides moderately
produced at middle, sinuate and convergent to anterior angle, sinuate and convergent to posterior; anterior border 0.44 mm
wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior
border 0.46 mm wide, slightly arcuate to rear. Posterointernal foveolae moderately developed; punctures in foveola similar
to those on disc. Posteroexternal foveola moderately developed. Interfoveolar depression moderately developed. Area
between external foveolae moderately elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent
shaped, extended across slightly less than 0.33 width of anterior region of pronotum. Transverse foveola slightly developed,
punctures closer together than punctures on disc. Disc moderately shining, punctures fine and close together, separated by
thin walls near anterior and posterior borders, and by puncture diameter in middle; most punctures with seta extended
above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae
separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae
divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively
narrow, sides nearly parallel, apex blunt, width at apex 0.50 distance between internal and median carinae. Metasternum
with plaques moderately developed, straight, convergent from posterior to anterior; plaques slightly less than 0.50 length of
metasternum in midline; width of each plaque subequal to width of intercoxal process at its midlength; plaques separated
anteriorly by approximately four times plaque width; plaques flat in cross section. Elytra: Length 1.10 mm. Maximum
width (at midlength) 0.55 mm. Surface moderately shining, disc with 10 rows of punctures between suture and humeral
callus, rows quite regular; most punctures round; intervals not elevated, width approximately equal to 0.50 puncture

Western Hemisphere Hydraenidae

149

diameter, as are interstices between adjacent punctures of a row; each puncture with seta. Explanate margin quite
narrow, ended near posterior 0.17, with extremely fine, well separated serrations along entire margin; serrations
somewhat closer near apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin
elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen : Intercoxal segment flat, wider than
long, posterior margin straight. Glabrous segments at apex moderately produced. Segment 7 without emargination at
apex. Legs: Metatibia gradually enlarged from base to apex. Genitalia: Aedeagus as illustrated (Fig. 44B)( 1 3
examined).

Distribution. - (Figs. 42B,168). Northeastern United States: Massachusetts, Connecticut,
New York, New Jersey and Pennsylvania.

Remarks. - In the original description of H. punctata , LeConte (1855) gives the length of
his specimen as “Long. .95”, which is equivalent to about 2.40 mm. This is apparently a
typographical error, as the specimen is actually only 1.48 mm long. D’Orchymont (1923) in his
early paper on American Hydraena comments that he had not seen the type-specimen of H.
punctata , and states further, “Je n’ai vu aucune Hydraena americaine de taille ausse grande.”
This probably explains why d’Orchymont later (1929) mistakenly described a specimen of H.
punctata as H. needhami. Including the two types, a total of 26 specimens were examined (see
appendix).

5 1 . Hydraena oblio new species
(Figs. 44A,59,168)

Type-locality. - Four miles S. Rabinal, Baja Verapaz, Guatemala.

Type-specimens. - The holotype male and allotype with same data are deposited in USNM.
My wife Maureen and I collected these specimens, June 10, 1974. Paratypes (13) are listed in
the appendix.

Diagnosis. - Small size and ovate body form (about 1.24 x 0.56 mm), plus pronotal
sculpture, which lacks a scintilla and has the interstices microreticulate, serve as diagnostic
characteristics for this distinctive species. The pronotum is very dull due to the
microreticulation.

Description. — Form: Ovate. Size: Holotype 1.24 mm long, 0.56 mm wide. Color: Dorsal surface dark brown
except head and disc of pronotum nearly black; maxillary palpi and antennae brown. Ventral surface dark brown except
legs, elytral epipleura and inflexed margin of pronotum brown. Head: Length 0.20 mm. Width 0.34 mm. Frons
microreticulate, punctures separated by less than their own diameters, microreticulation more evident in punctures than on
interstices; surface dull. Frontoclypeal suture straight. Clypeus microreticulate. Labroclypeal suture nearly straight when
viewed from above. Labrum bilobed, microreticulate, each lobe slightly asymmetrical; median emargination ending at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.20/0.08/0.14; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface very slightly arcuate, median surface moderately arcuate; palpomere 4 widest
slightly past midlength. Mentum wider than long, surface moderately shining, microreticulate. Submentum
microreticulate. Genae shining; lateral area of each gena with well developed foveola; posterior ridge very slightly
developed. Postgena with punctation slightly smaller than that of submentum. Last five antennomeres pubescent. Eyes
0.17 interocular distance in width. Thorax: Pronotum length at midline 0.32 mm; maximum width (at approximately
midlength) 0.46 mm; sides margined, denticulate; sides moderately produced at middle, very slightly sinuate and slightly
convergent to anterior angle, markedly sinuate, and convergent to posterior; anterior border 0.36 mm wide, straight and
nearly perpendicular to midline in lateral 0.17, moderately arcuate to rear in middle 0.50; posterior border 0.40 mm wide,
slightly arcuate to rear. Posterointernal foveolae well developed; punctures in foveola less distinct than those on disc.
Posteroexternal foveola well developed. Interfoveolar depression moderately developed. Area between external foveolae
moderately elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across
slightly less than 0.33 width of anterior region of pronotum. Transverse foveola moderately developed, punctures similar to
those on disc. Disc dull, microreticulate, punctures separated by 0.50 puncture diameter or less, some punctures with seta
extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short
spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and
external carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal
process relatively narrow, sides nearly parallel; apex round, width 0.50 distance between internal and median carinae.

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150

Perkins

Metasternum with plaques weakly developed, consisting of small ovals at posterior 0.20. Elytra: Length 0.82 mm.
Maximum width (at midlength) 0.56 mm. Surface dull, disc with 10 rows of punctures between suture and humeral
callus, rows quite regular; most punctures round but limits difficult to discern, surface uneven; intervals not elevated,
width approximately equal to 0.50 puncture diameter, as are interstices between adjacent punctures of row; each
puncture with seta. Explanate margin quite narrow, ended near posterior 0.12, with fine serrations near anterior angles.
Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture,
in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly an equilateral triangle, posterior
margin straight. Glabrous segments at apex moderately produced. Segment 7 without emargination at apex. Legs:
Protibia arcuate, very slightly expanded in apical 0.33. Metatibia with straight inner surface, outer surface very slightly
arcuate. Genitalia: Aedeagus as illustrated (Fig. 44A)(6 examined).

Natural History. - The stream at the type-locality is in a transition xeric-tropical zone, the
beetles being collected at the sand-gravel margins (Figs. 191 B-C).

Distribution. - (Figs. 59,168). Inhabits the mountains of Guatemala and Chiapas, Mexico.

Etymology. - oblio , a miscellaneous assemblage of letters.

52. Hydraena youngi new species
(Figs. 42B,45B,168)

Type-locality. - San Felasco Hammock, Alachua County, Florida.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CFMNH. Paratypes with same data (12) are deposited in FNY, USNM, and PDP. Frank

N. Young collected these specimens, October 28, 1947. One additional male paratype (PDP)
has the following data: Maryland, Worcester County, Pokomoke City, October 16, 1977, H. E.
Sprance. One additional female paratype (PDP), collected by Hubbard and Schwarz, is from
Ft. Monroe, Virginia.

Diagnosis. - Immediately distinguished from other Western Hemisphere Hydraena adults
by narrow body form (1.96 x 0.56 mm) and rugulose, dull pronotum. The aedeagus (Fig. 45b)
is extremely unusual.

Description. — Form: Narrow, elongate. Size: Holotype 1.96 mm long, 0.56 mm wide. Color: Head with dorsal
surface dark brown; labrum brown; maxillary palpi and antennae testaceous. Pronotum with an indistinctly defined, brown
macula on disc, remainder testaceous. Elytra brown. Ventral surface brown except legs, elytral epipleurae and inflexed
margins of pronotum ochraceous. Head: Length 0.20 mm. Width 0.34 mm. Frons moderately finely and closely punctured;
interstices equal to or slightly less than puncture diameter, surface dull, extremely uneven, limits of punctures difficult to
see with light reflected from surface. Frontoclypeal suture straight. Clypeus microreticulate. Labroclypeal suture arcuate
in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc, median emargination ended at
approximately midlength of labrum. Maxillary palpus with follqwing lengths (mm) of palpomeres 2, 3 and 4, respectively:

O. 26/0.12/0.20; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface nearly straight in basal 0.33, arcuate in apical 0.66, median surface arcuate;
palpomere 4 widest past midlength. Mentum wider than long, surface dull, microreticulate. Submentum microreticulate.
Genae dull, lateral area of each gena with well developed foveola; posterior ridge nearly imperceptible. Postgena with
microreticulation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly less than 0.20
interocular distance in width. Thorax: Pronotum length at midline 0.38 mm; maximum width (at approximately
midlength) 0.48 mm; sides margined, denticulate; sides relatively weakly produced at middle, very slightly arcuate and
slightly convergent to anterior angle, markedly sinuate and slightly convergent to posterior; anterior border 0.40 mm wide,
straight and nearly perpendicular to midline in lateral 0.14, markedly arcuate to rear in middle 0.71; posterior border
0.44 mm wide, slightly arcuate to rear. Posterointernal foveolae moderately developed; punctures in foveola similar to
those on disc. Posteroexternal foveola delimited by very shallow depression with punctation somewhat closer than that of
disc. Interfoveolar depression very slightly developed. Area between external foveolae not elevated. Anteroexternal
foveolae well developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior
region of pronotum. Transverse foveola not developed, punctures in this area somewhat closer together than punctures on
disc. Disc dull, punctures fine, separated by 0.50 puncture diameter near anterior and posterior borders, by puncture
diameter in middle; interstices extremely uneven, limits of punctures difficult to see with light reflected from surface;
punctures with distinctive setae extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina
produced anteriorly as very short spine; coxae separated by thin, median carina; carina arcuate line in lateral aspect.
Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to base of

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151

B

Figs. 45 A - B, Aedeagi of fiydraena holotypes. (A) H. cuspidicollis. (B) H. youngi (inset: specimen from Worcester
County, Maryland).

intercoxal process; intercoxal process relatively narrow, tapered from base to apex, apex blunt, width at apex slightly
less than 0.50 distance between internal and median carinae. Metasternum with plaques well developed, triangular,
median margins parallel; plaques nearly 0.50 length of metasternum in midline; plaques flat in cross section. Elytra:
Length 1.04 mm. Maximum width (at midlength) 0.56 mm. Surface dull, disc with 10 rows of punctures between
suture and humeral callus, rows 2-5 (from suture) somewhat irregular; most punctures round; intervals not elevated,
width approximately equal to puncture diameter, as are interstices between adjacent punctures of a row; surface of
interstices somewhat uneven; punctures each with seta. Explanate margin quite narrow, ended near posterior 0.20, with
fine serrations near anterior angles. Elytral apices, in dorsal aspect, somewhat produced; in posterior aspect, elytral
margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat,
nearly an equilateral triangle, posterior margin arcuate. Glabrous segments at apex well produced, somewhat flat on
ventral surface. Apical segment without emargination at apex. Legs: Profemur with a small tubercle on inner surface at
midlength. Protibia very slightly arcuate. Genitalia: Aedeagus as illustrated (Fig. 45B)(7 examined).

Variation. - The aedeagus of the single male known from Maryland (Fig. 45B, inset) differs
slightly from that of specimens from Florida. Externally, this specimen agrees well with the
Floridian individuals.

Distribution. - (Figs. 42B,168). Known only from the type-locality in Florida and one
locality in Maryland.

Etymology. - I am pleased to dedicate this species to Frank N. Young, in recognition of his
many contributions to the knowledge of way of life and systematics of aquatic Coleoptera.

The argutipes Subgroup

Adults of this subgroup are characterized by absence of a pronotal scintilla, absence of a
brush of hairs on the metatibiae of males, and the presence of an elevated ridge, more or less

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Perkins

developed, on the anteromedial region of the metasternum (e.g .H. cuspidicollis ), (Fig. 48D).
Adults of several of the eight included species have the pronotum distinctively incised on the
sides in the posterior 0.50. Two of the species, H. bractea and H. bractoides , have the male
metatibiae arcuate and expanded.

As is currently known, the subgroup is restricted to montane areas of Mexico from Oaxaca
to Durango.

53. Hydraena oaxaca new species
(Figs. 46D,169)

Type-locality. - One mile N. Ixtlan de Juarez, Oaxaca, Mexico.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. Paratypes consist of two specimens, one of each sex, from the same locality (PDP).
These specimens were collected by my wife Maureen and I, July 5, 1974.

Diagnosis. - The metasternal plaques are well developed, subtriangular, separated by
slightly more than the greatest width of a plaque. This characteristic plus the well developed
median ridge on the anterior portion of the metasternum and the moderately large size, about
1.70 mm long, serve to distinguish H. oaxaca adults from the other members of the leechi
Group which have serial punctures on the elytra and lack a pronotal scintilla.

Description. — Form: Elongate. Size: Holotype 1.70 mm long, 0.72 mm wide. Color: Dorsal surface dark brown
except border of pronotum, slightly lighter. Maxillary palpi testaceous; antennae testaceous. Ventral surface dark brown
except legs, elytral epipleura and inflexed margin of pronotum brown. Head: Length 0.22 mm. Width 0.40 mm. Frons
moderately punctured, interstices equal to or slightly less than puncture diameter; surface shining. Frontoclypeal suture
straight. Clypeus microreticulate, Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, each lobe symmetrical
arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.28/ 0.10/0.22; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface straight, median surface arcuate; apical
segment widest near midlength. Mentum wider than long, surface moderately shining, microreticulate. Submentum
microreticulate. Genae shining; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with
microreticulation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly less than 0.25
interocular distance in width. Thorax: Pronotum length at midline 0.40 mm; maximum width (at approximately
midlength) 0.56 mm; sides margined, denticulate; sides moderately produced at middle, slightly arcuate and slightly
convergent to anterior angle, slightly sinuate and convergent to posterior; anterior border 0.44 mm wide, straight and
nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.48 mm wide,
slightly arcuate to rear. Posterointernal foveolae weakly developed; punctures in foveola similar to those on disc.
Posteroexternal foveola delimited by very shallow depression with punctation somewhat closer than that of disc.
Interfoveolar depression moderately developed. Area between external foveolae moderately elevated. Anteroexternal
foveolae well developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior
region of pronotum. Transverse foveola slightly developed, with punctures somewhat closer together than punctures on
disc. Disc shining, punctures moderately large and deeply impressed, separated by thin walls near anterior and posterior
borders, by puncture diameter or slightly less in middle; each puncture with distinctive seta extended above cuticle in dry
specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin,
median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from
anterior to posterior; median median carina extended to base of intercoxal process; interocoxal process relatively broad,
sides parallel, apex blunt, width at apex subequal to distance between internal and median carinae. Metasternum with
ridge posterior to intercoxal process; plaques well developed, somewhat triangular, parallel; plaques 0.50 length of
metasternum in midline, greatest width of each plaque subequal to width of intercoxal process; plaques separated
posteriorly by approximately 1.50 times plaque width; plaques flat in cross setion. Elytra: Length 1.08 mm. Maximum
width (at midlength) 0.72 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows
quite regular; most punctures round; intervals not elevated, width approximately equal to puncture diameter, interstices
between adjacent punctures of row generaly smaller than puncture diameter; punctures each with seta. Explanate margin
quite narrow, ended near posterior 0.20, with extremely fine, well separated serrations along entire margin; serrations
somewhat closer near apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin
elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly an
equilateral triangle, posterior margin straight. Glabrous segments at apex only moderately produced. Segment 7

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153

emarginate at apex. Legs: Profemur with small tubercle on inner surface at basal 0.50. Protibia arcuate in basal 0.50,
expanded on inner surface near apical 0.33. Metatrochanter with small tubercle. Metatibia gradually enlarged from
base to apex; basal 0.25 slightly arcuate. Genitalia: Aedeagus as illustrated (Fig. 46D)(2 examined).

Natural History. - The type-series was removed from leaves and other debris which had
become trapped behind rocks in a moderately large stream. This stream was in a pine-oak
transition area (Fig. 195B). Consocies included H. scintilla and H. cuspidicollis.

Distribution. - (Fig. 169). Known only from the type-locality at the base of the mountains
just north of the small village of Ixtlan de Juarez. This village is approximately 25 miles north
of the city of Oaxaca.

Etymology. - Latin-like noun in apposition, oaxaca, in reference to the type-locality.

54. Hydraena scolops new species
(Figs. 46C,169)

Type-locality. - Real de Arriba, Temescaltepec, Mexico, Mexico.

Type-specimen. - The holotype male (unique) is deposited in BMNH. This specimen was
collected by H. E. Hinton and R. L. Usinger in 1932.

Diagnosis. - Differentiated from other species in the leechi Group whose adults also lack a
pronotal scintilla, have a low ridge on the metasternum posterior to the mesosternal intercoxal
process, have a relatively broad intercoxal process, and have the elytral punctures in series, by
shape and size of the plaques, which are shaped as elongate triangles. The inner margins are
parallel, while the outer margins converge anteriorly so that the anterior extreme of each
plaque is acute. The plaques are separated by slightly less than the basal width of a plaque.
Males have a very small, pointed process on the posterior margin of the metatrochanter.

Description. — Form: Elongate-oval. Size: Holotype 1.48 mm long, 0.64 mm wide. Color: Head with dorsal surface
dark brown; labrum dark brown; maxillary palpi brown; antennae brown. Pronotum brown at anterior and posterior 0.50,
dark brown in center 0.50; sides slightly lighter than center. Elytra brown. Ventral surface dark brown except legs, elytral
epipleura and inflexed margin of pronotum brown. Head: Length 0.20 mm. Width 0.36 mm. Frons moderately punctured,
most interstices slightly greater than puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus
microreticulate. Labroclypeal suture nearly straight across middle in dorsal aspect. Labrum bilobed, microreticulate, each
lobe symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with following
lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.26/0.12/0.20; palpomere 2 bent outward at approximately
midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly straight in basal
0.33, arcuate in apical 0.66, median surface arcuate; apical segment widest near midlength. Mentum wider than long,
surface moderately shining, microreticulate. Submentum microreticulate. Genae shining; lateral area of each gena with
well developed foveola; posterior ridge absent. Postgena with microreticulation slightly larger than that of submentum.
Last five antennomeres pubescent. Eyes slightly less than 0.20 interocular distance in width. Thorax: Pronotum length at
midline 0.36 mm; maximum width (at approximately midlength) 0.48 mm; sides margined, denticulate; sides moderately
produced at middle, slightly arcuate and convergent to anterior angle, slightly sinuate and convergent to posterior; anterior
border 0.38 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle
0.50; posterior border 0.42 mm wide, slightly arcuate to rear. Posterointernal foveolae moderately developed; punctures in
foveola closer together than those on disc. Posteroexternal foveola delimited by very shallow depression with punctation
somewhat closer than that of disc. Interfoveolar depression slightly developed. Area between foveolae weakly elevated.
Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33
width of anterior region of pronotum. Transverse foveola slightly developed, with punctures closer together than punctures
on disc. Disc shining, punctures fine, separated by 0.50 puncture diameter near anterior and posterior borders by puncture
diameter or slightly greater in middle; punctures each with seta extended above cuticle in dry specimens. Scintilla absent.
Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin, median carina; carina
sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median
carina extended to base of intercoxal process; intercoxal process relatively broad, sides nearly parallel, apex round, width
slightly less than distance between internal and median carinae. Metasternum with prominent ridge immediately posterior
to intprcoxal process; plaques well developed, triangular, medial surfaces parallel; plaques nearly 0.50 length of
metasternum in midline; greatest width of each plaque subequal to width of intercoxal process; plaques separated by
approximately greatest width of plaque; plaques flat in cross section. Elytra: Length 0.96 mm. Maximum width (at

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154

Perkins

Figs. 46A - D, Aedeagi of Hydraena holotypes. (A) H. crystallina. (B) H. mazamitla. (C) H. scolops. (D) H. oaxaca.

midlength) 0.64 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite
regular; most punctures round; intervals not elevated, width slightly less than puncture diameter, as are interstices
between adjacent punctures of a row; punctures each with seta. Explanate margin quite narrow, ended near posterior
0.20, with extremely fine serrations near apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect,
elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment
flat, nearly an equilateral triangle, posterior margin straight. Glabrous segments at apex moderately produced. Segment
7 without emargination at apex. Legs: Profemur with minute tubercle on inner surface at midlength. Protibia expanded
on inner surface near apical 0.33. Metatrochanter with acute tubercle on posterior margin. Metatibia parallel sided in

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155

apical 0.66. Genitalia: Aedeagus as illustrated (Fig. 46C)(1 examined).

Distribution. - (Fig. 169). Known only from the type-locality near Temescaltepec in the
state of Mexico, Mexico.

Etymology. - Greek, skolops (thorn). This name refers to the small, pointed process on the
hind margin of the metatrochanters.

55. Hydraena crystallina new species
(Figs. 46A,169)

Type-locality. - Seven miles S. Mazamitla, Jalisco, Mexico.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. These specimens were collected by my wife Maureen and I, July 15, 1974. Paratypes
consist of one male and two females (PDP) with same data as holotype plus five males and
eight females (CAS) collected by Hugh B. Leech at the type-locality, December 1, 1948.

Diagnosis. - Among those species of the leechi Group whose adults have an anterior median
ridge on the metasternum and have the mesosternal intercoxal process relatively broad, adults
of H. crystallina are distinguished by the plaques, which are narrow, non-elevated and
separated by more than twice the width of a plaque.

Description. — Form: Elongate. Size: Holotype 1 .38 mm long, 0.60 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior and posterior
0.25, dark brown in middle 0.50; sides slightly lighter than center. Elytra brown. Ventral surface dark brown except legs,
elytral epipleura mentum and inflexed margin of pronotum testaceous. Head: Length 0.20 mm. Width 0.34 mm. Frons
moderately punctured, interstices equal to or slightly greater than puncture diameter; surface shining. Frontoclypeal
suture straight. Clypeus finely punctulate. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed; surface
punctulate; each lobe symmetrical arc; median emargination ended above midlength of labrum. Maxillary palpus with
following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.26/0.10/0.20; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface very
slightly arcuate; median surface evenly arcuate; palpomere 4 widest slightly past midlength. Mentum wider than long,
surface moderately shining, finely punctulate. Submentum microreticulate. Genae shining; lateral area of each gena with
well developed foveola; posterior ridge absent. Postgena with microreticulation slightly larger than that of submentum.
Last five antennomeres pubescent. Eyes slightly greater than 0.25 interocular distance in width. Thorax: Pronotum length
at midline 0.34 mm; maximum width (at approximately midlength) 0.48 mm; sides margined, denticulate; sides
moderately produced at middle, slightly arcuate and convergent to anterior angle, slightly sinuate and convergent to
posterior; anterior border 0.38 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate
to rear in middle 0.50; posterior border 0.42 mm wide, slightly arcuate to rear. Posterointernal foveolae weakly developed;
punctures in foveola closer together than those on disc. Posteroexternal foveola delimited by very shallow depression with
punctation somewhat closer than that of disc. Interfoveolar depression slightly developed. Area between external foveolae
slightly elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across slightly
less than 0.33 width of anterior region of pronotum. Transverse foveola not developed, punctures in this area somewhat
closer together than punctures on disc. Disc shining, punctures fine, separated by approximately puncture diameter;
punctures each with distinctive seta extended above cuticle in dry specimens. Scintilla absent, margin very slightly
produced in this area. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin,
median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from
anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively broad, sides nearly
parallel in apical 0.50, apex blunt, width at apex subequal distance between internal and median carinae. Metasternum
with ridge posterior to intercoxal process; plaques well developed, somewhat triangular, convergent slightly from posterior
to anterior; plaques 0.41 length of metasternum in midline; width of each plaque 0.33 width of intercoxal process at its
midlength; plaques separated posteriorly by approximately three times plaque width; plaques flat in cross section. Elytra:
Length 0.90 mm. Maximum width (at midlength) 0.60 mm. Surface shining, disc with 10 rows of punctures between
suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width approximately equal to
-puncture diameter, as are interstices between adjacent punctures of a row; punctures each with seta. Explanate margin
quite narrow, ended near posterior 0.10, with extremely fine, well separated serrations along entire margin; serrations
somewhat closer near apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin
elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly an
equilateral triangle, posterior margin straight. Glabrous segments at apex moderately produced. Segment 7 emarginate at

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Perkins

apex. Legs: Profemur with minute tubercle on inner surface near midlength. Protibia slightly expanded on inner surface
near apical 0.33. Metatibia slightly wider at middle than at apex. Genitalia: Aedeagus as illustrated (Fig. 46A)(7
examined).

Natural History. - Refer to H. scopula.

Distribution. - (Fig. 169). Known only from the type-locality near Mazamitla in the state of
Jalisco, Mexico.

Etymology. - Latin, crystallina (of crystal). Named in reference to the transparency of the
aedeagus.

56. Hydraena mazamitla new species
(Figs. 46B,169)

Type-locality. - Seven miles S. of Mazamitla, Jalisco, Mexico.

Type-specimens. - The holotype male and allotype with same data are deposited in CAS.
Hugh B. Leech collected these specimens, December 1, 1948.

Diagnosis. - Small size, about 1.36 mm long, moderately shiny pronotum, lack of a scintilla,
weakly elevated anteromedial ridge on the metasternum, and plaque form are the primary
differentiating external features of this species. The plaques are well developed, convergent
anteriorly, separated posteriorly by nearly twice plaque width, and rounded in cross-section.
The aedeagus (Fig. 46B) is very distinctive.

Description. — Form: Elongate. Size: Holotype 1.36 mm long, 0.60 mm wide. Color: Head with dorsal surface
brown, darker near eyes; labrum brown; maxillary palpi testaceous; antennae testaceous. Pronotum with brown macula on
disc, surrounding areas testaceous. Elytra brown. Ventral surface brown except legs, elytral epipleura and inflexed margin
of pronotum light brown. (This specimen appears to be slightly teneral.) Head: Length 0.20 mm. Width 0.34. Frons
moderately punctured, interstices equal to or slightly greater than puncture diameter; surface shining. Frontoclypeal
suture straight. Clypeus microreticulate. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate,
each lobe symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with
following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.24/0.12/0.18; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly
straight in basal 0.33, arcuate in apical 0.66, median surface evenly arcuate; palpomere 4 widest slightly past midlength.
Mentum wider than long, surface shining, finely punctulate. Submentum microreticulate. Genae shining; lateral area of
each gena with well developed foveola; posterior ridge absent. Postgena with microreticulation slightly larger than that of
submentum. Last five antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width. Thorax:
Pronotum length at midline 0.32 mm; maximum width (at approximately midlength) 0.48 mm; sides margined,
denticulate; sides moderately produced at middle, slightly arcuate and slightly convergent to anterior angle, slightly
sinuate and convergent to posterior; anterior border 0.38 mm wide, straight and nearly perpendicular to midline in lateral
0.25; moderately arcuate to rear in middle 0.50; posterior border 0.42 mm wide, slightly arcuate to rear. Posterointernal
foveolae slightly developed; punctures in foveola closer together than those on disc. Posteroexternal foveola delimited by
very shallow depression with punctation somewhat closer than that of disc. Interfoveolar depression slightly developed.
Area between external foveolae weakly elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent
shaped, occupying slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not developed,
punctures in this area somewhat closer together than punctures on disc. Disc shining, punctures fine, separated by
puncture diameter near anterior and posterior borders, and by twice puncture diameter in middle; most punctures with
seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very
short spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and
external carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal
process relatively narrow, sides nearly parallel, apex blunt, width at apex 0.66 distance between internal and median
carinae. Metasternum with median, anterior ridge; plaques well developed, triangular, convergent very slightly from
posterior to anterior; plaques nearly 0.50 length of metasternum in midline, greatest width of each plaque subequal to
width of intercoxal process; plaques separated posteriorly by slightly greater than plaque width; plaques slightly rounded in
cross section. Elytra: Length 0.84 mm. Maximum width (at midlength) 0.60 mm. Surface shining, disc with 10 rows of
punctures between suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width
approximately equal to 0.50 puncture diameter, as are interstices between adjacent punctures of a row; punctures each
with a seta. Explanate margin quite narrow, ended near posterior 0.20, with extremely fine serrations near apices. Elytral
apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of

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157

angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous
segments at apex moderately produced. Segment 7 without emargination at apex. Legs: Profemur with tubercle on inner
surface near basal 0.33. Protibia slightly expanded on inner surface near apical 0.33. Mesotibia flattened on inner
surface near apex. Metatibia nearly parallel sided in apical 0.50. Genitalia: Aedeagus as illustrated (Fig. 46B)(1
examined).

Natural History. - Refer to Hydraena scopula.

Distribution. - (Fig. 169). Known only from the type-locality near Mazamitla, Jalisco,
Mexico.

Etymology. - Latin-like noun in apposition, mazamitla , in reference to the type-locality.

57. Hydraena prieto new species
(Figs. 42A,47A,169)

Type-locality. - One mile W. Los Bancos, Durango, Mexico.

Type-specimens. - The holotype male and allotype with same data are deposited in USNM.
My wife Maureen and I collected these specimens, July 17, 1974. Paratypes (29) are listed in
the appendix.

Diagnosis. - The metasternal plaques are very narrow, slightly elevated, and widely
separated, the distance being about five times the width of a plaque. Form of the plaques plus
the shiny, moderately sparsely punctate pronotum serve to distinguish H. prieto adults from
other members of the leechi Group which lack a scintilla and have the anteromedial region of
the metasternum elevated.

Description. — Form: Elongate. Size: Holotype 1.50 mm long, 0.66 mm wide. Color: Dorsal surface dark brown,
nearly black, except narrow brownish border around pronotum; maxillary palpi testaceous; antennae testaceous. Ventral
surface dark brown except legs, elytral epipleura and inflexed margin of pronotum brown. Head: Length 0.22 mm. Width
0.40 mm. Frons finely and sparsely punctured, interstices two-three times puncture diameter; surface shining,
Frontoclypeal suture straight. Clypeus finely microreticulate, shiny. Labroclypeal suture arcuate when viewed from above.
Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of
labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.24/0.12/0.20;
palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4
with lateral surface nearly straight, median surface evenly arcuate; palpomere 4 widest near midlength. Mentum wider
than long; surface moderately shining, finely microreticulate. Submentum microreticulate. Genae shining; lateral area of
each gena with well developed foveola; posterior ridge absent. Postgena with microreticulation slightly larger than that of
submentum. Last five antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width. Thorax:
Pronotum length at midline 0.36 mm; maximum width (at approximately midlength) 0.54 mm; sides margined,
denticulate; sides moderately produced at middle, slightly arcuate and convergent to anterior angle, sinuate and
convergent to posterior; anterior border 0.44 mm wide, straight and nearly perpendicular to midline in lateral 0.25,
moderately arcuate to rear in middle 0.50; posterior border 0.46 mm wide, slightly arcuate to rear. Posterointernal foveolae
moderately developed; punctures in foveola similar to those on disc. Posteroexternal foveola moderately developed, with
punctation somewhat closer than that of disc. Interfoveolar depression moderately developed. Area between external
foveolae weakly elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across
slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not developed. Disc shining, punctures fine,
separated by two-three times puncture diameter; punctures each with distinctive seta extended above cuticle in dry
specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly into very short spine; coxae separated by thin,
median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from
anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively broad, sides nearly
parallel; apex blunt, width at apex slightly less than distance between internal and median carinae. Metasternum with
ridge posterior to intercoxal process; plaques moderately developed, thin, very slightly carinate, convergent moderately
from posterior to anterior; plaques 0.50 length of metasternum in midline; width of each plaque 0.33 width of intercoxal
process at its midlength; plaques separated posteriorly by nearly four times plaque width; plaques located on sides of
median depression, therefore sloped toward midline. Elytra: Length 0.96 mm. Maximum width (at midlength) 0.66 mm.
Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most punctures
round; intervals not elevated, width approximately equal to puncture diameter or slightly greater, as are interstices
between adjacent punctures of a row; punctures each with a seta. Explanate margin quite narrow, ended near posterior
0.20, with extremely fine, well separated serrations near anterior angles and apices. Elytral apices, in dorsal aspect,

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gradually rounded; viewed posteriorly, elytral margin rises obliquely towards suture, forming an angle with opposite
elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous segments at apex
moderately produced. Segment 7 apparently not emarginate at apex (obscured by pubescence). Legs: Protibia expanded
on inner surface at apical 0.33. Mesotibia flattened on inner surface at apex. Metatibia gradually expanded from base
to apex. Genitalia: Aedeagus as illustrated (Fig. 47A)(19 examined).

Natural History. - The stream at the type-locality is rather rapid, flowing through a pine
forest. The beetles were taken at the sand-gravel margin, as were a few specimens of
Ochthebius mexcavatus. Adults of this species were also found in association with Hydraena
alternata, “ex under stones in a small creek in the mountains”.

Distribution. - (Figs. 42A,169). Found in the mountains of Durango and Jalisco, Mexico.

Etymology. - prieto, in reference to Prieto Mountain in the mountains of Durango near the
type-locality. The name also refers to the dark coloration of this species.

Remarks. - Los Bancos is a small village near the type-locality, which is about 100 miles
west of Durango, on highway MEX. 40.

58. Hydraena argutipes new species
(Figs. 47B,169)

Type-locality. - Two miles E. of Durango-Sinaloa boundary on highway MEX. 40, 7000
feet, Durango, Mexico.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. These specimens plus 10 paratypes (8 CAS; 2 PDP) from the same locality were
collected by D. E. Breedlove and J. F. Copp, December 30, 1962.

Diagnosis. - The metasternal plaques are well developed, have the lateral margins elevated
slightly, and are separated by slightly more than the width of a plaque. This feature, plus the
ochraceous legs and palpi serve to distinguish H. argutipes adults from those of other species of
the leechi Group which also lack a pronotal scintilla and have the anteromedial region of the
metasternum elevated.

Description. — Form: Elongate. Size: Holotype 1.46 mm long, 0.64 mm wide. Color: Dorsal surface dark brown,
nearly black, except narrow brownish border around pronotum; maxillary palpi testaceous, nearly yellow; antennae
testaceous. Ventral surface dark brown except legs, elytral epipleura, mentum and inflexed margin of pronotum,
brownish-orange. Head: Length 0.20 mm. Width 0.36 mm. Frons sparsely punctured, interstices twice puncture diameter;
surface shining. Frontoclypeal suture straight. Clypeus microreticulate. Labroclypeal suture arcuate when viewed from
above. Labrum bilobed, microreticulate, each lobe a symmetrical arc; median emargination ended at approximately
midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.28/0.12/0.20; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface slightly arcuate, median surface much more arcuate; apical segment widest
near midlength. Mentum wider than long, surface shining, finely microreticulate. Submentum microreticulate. Genae
shining; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with microreticulation
slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly less than 0.25 interocular distance
in width. Thorax: Pronotum length at midline 0.36 mm; maximum width (at approximately midlength) 0.50 mm; sides
margined, denticulate; sides moderately produced at middle, slightly arcuate and convergent to anterior angle, slightly
sinuate and convergent to posterior; anterior border 0.40 mm wide, straight and nearly perpendicular to midline in lateral
0.25, moderately arcuate to rear in middle 0.50; posterior border 0.44 mm wide, slightly arcuate to rear. Posterointernal
foveolae moderately developed; punctures in foveola closer together than those on disc. Posteroexternal foveola delimited
by very shallow depression with punctation somewhat closer than that of disc. Interfoveolar depression weakly developed.
Area between external foveolae weakly elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent
shaped, extended across slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not developed,
punctures in this area somewhat closer together than punctures on disc. Disc shining, punctures moderately fine, separated
by thin walls near anterior and posterior borders, and by puncture diameter or less in middle; many punctures with seta
extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as short spine;
coxae separated by thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external
carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process

Western Hemisphere Hydraenidae

Figs. 47A - D, Aedeagi of Hydraena holotypes. (A) H. prieto. (B) H. argutipes. (C) H. bractea. (D) H. bractoides.

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Perkins

relatively broad, sides nearly parallel in apical 0.50, apex blunt, width at apex subequal to distance between internal
and median carinae. Metasternum with prominent ridge posterior to intercoxal process; plaques well developed,
somewhat triangular, remarkably reflective, medial margins parallel; plaques 0.50 length of metasternum in midline;
greatest width of each plaque 0.66 width of intercoxal process at its midlength; plaques separated posteriorly by slightly
less than twice plaque width; plaque lateral margin elevated, each plaque sloped toward midline. Elytra: Length
0.94 mm. Maximum width (at midlength) 0.64 mm. Surface shining, disc with 10 rows of punctures between suture
and humeral callus, rows quite regular; most punctures round; intervals not elevated, width approximately equal to
puncture diameter, as are interstices between adjacent punctures of a row; punctures each with a seta. Explanate
margin narrow, ended near posterior 0.20, with extremely fine serrations near apices. Elytral apices, in dorsal aspect,
gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite
elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous segment at apex
moderately produced. Segment 7 emarginate at apex. Legs: Profemur with small tubercle on inner surface near
midlength. Protibia expanded on inner surface near apical 0.33. Mesotibia flattened on inner surface at apex. Metatibia
gradually expanded from base to apex. Genitalia: Aedeagus as illustrated (Fig. 47 B)(3 examined).

Distribution. - (Fig. 169). Known only from the type-locality in the mountains of Durango,
Mexico.

Etymology. - Latin, arguta (bright) plus ipes (foot). This name refers to the brightly
colored, ochraceous legs which contrast attractively with the dark brown dorsum and venter.

59. Hydraena brae tea new species
(Figs. 47C,169)

Type-locality. - Two miles E. of Durango-Sinaloa boundary on highway MEX. 40,
Durango, Mexico.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. One female paratype with same data is in PDP. These specimens were collected by D.
E. Breedlove and J. F. Copp, December 30, 1962.

Diagnosis. - The metasternal plaques of adults of this species are very distinctive due to
their large size and very smooth, extremely shiny surfaces. They lie on the sides of a shallow
median depression, occupying about 0.20 of the posterior part of the metasternum. Each plaque
is slightly wider than the distance separating them, much wider than the mesosternal process,
and tapers slightly anteriorly. The mesosternal process is very narrow, the width of its apex
being about 0.20 the distance separating the internal and median carinae. There is a sharp
elevated ridge on the metasternum posterior to the mesosternal process, and the pronotum lacks
a scintilla. Externally, H. bractea males are very similar to those of H. bractoides, but the
aedeagi are quite dissimilar (Figs. 47C-D). Refer to the diagnosis of H. bractoides for further
comments.

Description. — Form: Ovate. Size: Holotype 1.36 mm long, 0.64 mm wide. Color: Dorsal surface very dark brown,
nearly black, except anterior 0.25 and posterior 0.12 of pronotum brown. Maxillary palpi brown; antennae brown. Ventral
surface dark brown except legs, elytral epipleura and inflexed margin of pronotum brown. Head: Length 0.20 mm. Width
0.36 mm. Frons coarsely punctate, interstices less than puncture diameter; surface shining. Frontoclypeal suture straight.
Clypeus microreticulate. Labroclypeal suture straight in dorsal aspect. Labrum bilobed, microreticulate, each lobe
symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with following
lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.24/0.12/0.16; palpomere 2 bent outward at approximately
midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface arcuate in basal 0.25,
nearly straight in apical 0.75, median surface arcuate; palpomere 4 widest slightly past midlength. Mentum wider than
long, surface moderately shining, microreticulate. Submentum microreticulate. Genae shining; lateral area of each gena
with a well developed foveola; posterior ridge absent. Postgena with microreticulation similar to that of submentum. Last
five antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width. Thorax: Pronotum length at
midline 0.36 mm; maximum width (at approximately midlength) 0.50 mm; sides margined, denticulate; sides moderately
produced at middle, slightly arcuate and slightly convergent to anterior angle, sinuate and rather markedly convergent to
posterior; anterior border 0.40 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate
to rear in middle 0.50; posterior border 0.42 mm wide, slightly arcuate to rear. Posterointernal foveolae well developed;

Western Hemisphere Hydraenidae

161

punctures in foveola closer together than those on disc, some confluent. Posteroexternal foveolae well developed, with
punctation closer than that of disc. Interfoveolar depression moderately developed. Area between external foveolae
moderately elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, occupying slightly
less than 0.33 width of anterior region of pronotum. Transverse foveola well developed. Disc dull, punctures of moderate
size and deeply impressed; interstices with surfaces somewhat uneven varied from thin walls to puncture diameter; most
punctures with distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina
produced anteriorly as very short spine: coxae separated by thin, median carina; carina a sinuate line in lateral aspect.
Mesosternum with internal and external carinae divergent from anterior to posterior; median carina continued to base
of intercoxal process; intercoxal process extremely narrow, sides tapered, apex somewhat carinate, width at apex 0.20
distance between internal and median carinae. Metasternum with median keel posterior to intercoxal process; plaques
markedly developed, straight, median margins parallel; plaques 0.54 length of metasternum in midline; width of each
plaque four-five times width of intercoxal process at its apex; plaques separated by approximately 0.66 plaque width;
plaques highly reflective. Elytra: Length 0.92 mm. Maximum width (at midlength) 0.64 mm. Surface shining, disc with
10 rows of punctures between suture and humeral callus, rows quite regular; most punctures round; intervals not
elevated, width approximately equal to 0.50 puncture diameter, as are interstices between adjacent punctures of a row;
each puncture with a seta. Explanate margin moderately developed, ended near apices, without perceptible serrations
along margin. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin not elevated
obliquely toward suture, not in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly an
equilateral triangle, posterior margin straight. Glabrous segments at apex missing from specimen. Legs: Protibia
arcuate; apical 0.33 expanded on inner surface. Metatrochanter with carina. Metafemur broad, lateral surface arcuate,
medial surface sinuate. Metatibia arcuate; apical 0.50 expanded. Genitalia: Aedeagus as illustrated (Fig. 47C)(1
examined).

Distribution. - (Fig. 169). Known only from the type-locality in the mountains of Durango,
Mexico.

Etymology. - Latin, bractea (thin metal plate, gold leaf). This name refers to the smooth,
very reflective plaques.

60. Hydraena bractoides new species
(Figs. 47D,169)

Type-locality. - 24 miles W. La Ciudad, Durango, Mexico.

Type-specimens. - The holotype male (unique) is deposited in CNC. This specimen was
collected by H. F. Howden, June 15, 1964.

Diagnosis. - H. bractoides adults are very similar to those of H. bractea in habitus
appearance and form of the metasternal plaques (refer to the diagnosis of H. bractea for a
description of the plaques). Additionally, they share the following features: (1) absence of a
pronotal scintilla, (2) very thin mesosternal process, its width being about 0.20 the distance
separating the internal and median carinae, and (3) presence of an anteromedial ridge on the
metasternum. H. bractoides adults differ from those of H. bractea in their more deeply
impressed posterointernal foveolae, less rounded elytral sides, and, in males, the more strongly
expanded hind tibiae. These differences are very minor indeed when compared to the
differences in aedeagi (Figs. 47C-D).

Description. — Form: Ovate. Size: Holotype 1.34 mm long, 0.60 mm wide. Color: Dark brown. Head: Length
0.24 mm; width 0.34 mm. Frons coarsely punctate; interstices equal to or less than puncture diameter; shining.
Frontoclypeal suture arcuate. Clypeus finely punctulate in middle, microreticulate laterally. Labroclypeal suture straight.
Labrum bilobed, microreticulate; median emargination ending at about midlength. Maxillary palpus with following
lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.20/ 0.10/0.14; palpomere 4 with medial surface more markedly
arcuate than lateral. Mentum width equal length, moderately shiny, finely microreticulate. Submentum microreticulate.
Genae shiny, lateral area of each gena with well developed foveola; posterior ridge absent. Postgena microreticulate.
Thorax: Pronotum length at midline 0.34 mm; maximum width (slightly before midlength) 0.48 mm; sides margined,
denticulate, moderately produced at middle, slightly arcuate and slightly convergent to anterior angles, sinuate and rather
markedly convergent to posterior angles; anterior border 0.38 mm wide, straight and nearly perpendicular to midline in
lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.40 mm wide, slightly arcuate to rear.
Posterointernal foveolae well developed, deep; punctures in foveola closer together than those on disc, some confluent.

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Perkins

Posteroexternal foveolae well developed, punctation similar to that on disc. Interfoveolar depression moderately
developed. Area between external foveolae moderately elevated. Anteroexternal foveolae well developed, each extended
slightly less than 0.33 width of anterior region of pronotum. Transverse foveola well developed, punctures closer
together than those on reliefs. Disc moderately dull, densely, moderately coarsely punctate, most punctures with
distinctive seta; interstices shiny. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine;
coxae separated by thin median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external
carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process
narrow, carinate, width at apex 0.33 distance between internal and median carinae. Metasternum with low median
carina behind intercoxal process; plaques large, parallel, very shiny, in slight depression; each plaque width three times
that of intercoxal process, length 0.60 that of metasternum in midline; plaques separated by 0.66 plaque width. Elytra:
Length 0.88 mm. Maximum width (at midlength) 0.60 mm. Surface dull, disc with 10 rows of punctures between
suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width about equal to 0.50
puncture diameter, as are interstices between adjacent punctures of a row; each puncture with an indistinct seta.
Explanate margin rather well developed, ended near apices, without perceptible serrations along margin. Elytral apices,
in dorsal aspect, gradually rounded; in posterior aspect, elytral margin not elevated obliquely toward suture, not in form
of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly an equilateral triangle, posterior margin
straight. Glabrous segments at apex not distinctively produced. Legs: Protibia arcuate, apical 0.33 expanded on inner
surface. Metafemur moderately broad, lateral surface arcuate, median surface sinuate. Metatibia arcuate, apical 0.50
expanded. Genitalia: Aedeagus as illustrated (Fig. 47D)(1 examined).

Distribution. - (Fig. 169). Known only from the type-locality near La Ciudad in the state of
Durango, Mexico.

Etymology. - Latin, bractoides , in reference to the similarity to Hydraena bractea.

61. Hydraena cuspidicollis new species
(Figs. 42A,45 A,48 A-I,6 1 E-H, 1 69)

Type-locality. - One mile N. Ixtlan de Juarez, Oaxaca, Mexico.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. My wife Maureen and I collected these specimens, July 5, 1974. Paratypes (72) are
listed in the appendix.

Diagnosis. - Immediately distinguished from adults of other Western Hemisphere
Hydraena by the broad, depressed body form and pronotal shape, with anterior angles
produced (Figs. 48 A, C).

Description. — Form: Ovate. Size: Holotype 1.60 mm long, 0.80 mm wide. Color: Dorsal surface dark brown,
except pronotum with faint testaceous border. Maxillary palpi testaceous; antennae testaceous. Ventral surface dark
brown except legs, elytral epipleura and inflexed margin of pronotum orange-brown. Head: Length 0.20 mm. Width
0.42 mm. Frons moderately punctured, interstices equal to or slightly greater than puncture diameter; surface moderately
shining, setae quite prominent. Frontoclypeal suture straight. Clypeus finely punctulate. Labroclypeal suture nearly
straight across middle in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination
ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4,
respectively; 0.24/0.10/0.16; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not
especially expanded; palpomere 4 with lateral surface nearly straight, median surface arcuate; palpomere 4 widest near
midlength. Mentum wider than long, surface moderately shining, finely microreticulate. Submentum microreticulate.
Genae shining; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with punctation
similar to that of submentum. Last five antennomeres pubescent. Eyes 0.20 interocular distance in width. Thorax:
Pronotum length at midline 0.36 mm; maximum width (at approximately midlength) 0.62 mm; sides with furrow,
denticulate at sides, upper surface finely, extremely densely punctured; rather markedly produced at middle, slightly
arcuate and slightly convergent to anterior angle, markedly sinuate and markedly convergent to posterior; anterior border
0.48 mm wide, angles produced anteriorly, lateral 0.20 arcuate to rear, in form of recessed area, receptacle for posterior
margin of eye, middle 0.60 slightly arcuate to rear; posterior border 0.52 mm wide, slightly arcuate to rear. Posterointernal
foveolae markedly developed; punctures in foveola similar to those on disc. Posteroexternal foveola well developed, with
punctation somewhat less distinct than that of disc. Interfoveolar depression moderately developed. Area between external
foveolae well elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, occupying 0.33
width of anterior region of pronotum. Transverse foveola moderately developed, with punctures somewhat closer together
than punctures on disc. Disc shining, punctures moderately large and deeply impressed, separated by puncture diameter;
most punctures with distinctive seta extended above cuticle in dry specimens, scintilla absent. Prosternum carinate, carina

Western Hemisphere Hydraenidae

163

Figs. 48 A - I, Hydraena cuspidicollis, 9. (A) dorsal habitus. (B) ventral habitus. (C) pronotum (arrows indicate pronotal
sensilla). (D) metasternum (arrow indicates ridge posterior to intercoxal process). (E) head, ventral aspect. (F) labrum,
dorsal aspect. (G) protibia. (H) pro- and mesosternum. (1) detail of inflexed pronotal margin.

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Perkins

produced anteriorly as very short spine; coxae separated from median carina by thin shelf; carina sinuate line in lateral
aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to
base of intercoxal process; intercoxal process relatively broad, sides nearly parallel, apex blunt, width at apex 0.66
distance between internal and median carinae. Metasternum with median ridge posterior to intercoxal process; plaques
well developed, somewhat triangular, nearly parallel; plaques 0.41 length of metasternum in midline; greatest width of
each plaque subequal to width of intercoxal process; plaques separated posteriorly by approximately twice plaque width;
plaques on sides of median depression, sloped toward midline. Elytra: Length 1.08 mm. Maximum width (at midlength)
0.80 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most
punctures round; intervals not elevated, width slightly greater than puncture diameter, interstices between adjacent
punctures of row generally smaller than puncture diameter; each puncture with seta. Explanate margin relatively broad,
extended nearly to apices, with fine serrations near anterior angles. Elytral apices, in dorsal aspect, gradually rounded;
in posterior aspect, elytral margin elevated extremely slightly, obliquely toward suture, in form of slight angle with
opposite elytron. Abdomen: Intercoxal segment flat, nearly an equilateral triangle, posterior margin arcuate. Glabrous
segments at apex slightly produced. Segment 7 without emargination at apex. Legs: Protibia arcuate, enlarged in apical
0.50. Metatrochanter with small tubercle. Metatibia arcuate in basal 0.50, enlarged and with brush of hairs in apical
0.50 (Figs. 61E-H). All tarsi with prominent setae. Genitalia: Aedeagus as illustrated (Fig. 45A)(3 examined).

Natural History. - Refer to Hydraena scintilla for notes concerning the type-locality. Refer
also to the natural history notes of Hydraena scopula and Spanglerina ingens.

Distribution. - (Figs. 42A,169). Central Mexico, in the states of Jalisco, Nayarit, Mexico,
Veracruz and Oaxaca.

Etymology. - Latin, cuspidis (pointed end) plus collis (neck). This epithet refers to the
produced anterior angles of the pronotum.

Remarks. - Of the 73 specimens known to date, only three are males.

The marginicollis Group

Adults of marginicollis Group are quite similar to those of the lee chi Group in many
respects, but lack the posterointernal foveolae of the pronotum seen in the latter.

Many species in this group are comprised of quite small members that are very similar to
one another externally. The aedeagi, however, are very complex in many instances, and
generally differ greatly between species.

The group is very widespread, found from northern Argentina to the southern United States
(Fig. 160).

The marginicollis Subgroup

Adults of species included in the marginicollis Subgroup have the procoxae separated by a
thin carina and the mesosternal process is relatively narrow compared to that of adults of the
geminya Subgroup (cf. Figs. 54B,I,63A-B,F). Except for a very few species, such as H.
anisonycha , H. d-destina and H. barricula, the metatibiae of males are unmodified. Male
protibiae, however, are usually modified in some manner, generally with an excavation on the
inner surface near the apex (Figs. 54G-H). Males of many species have the last abdominal
segments greatly produced (e.g. Fig. 63B).

Many of the species included in this subgroup are small and very similar to one another
externally. The aedeagus, however, shows remarkable differences between species, and should
be examined when members of this Subgroup are studied. The species complexes used herein
are based upon aedeagal affinities. Most of these complexes are quite consistent with
biogeographical data (see section on phylogeny).

Western Hemisphere Hydraenidae

165

The marginicollis Subgroup, which currently consists of 30 species, ranges from the eastern
United States south through Mexico, Central America and the Antilles to northern Argentina.
The greatest species diversity is in the mountains of southern Mexico (Chiapas) and
Guatemala, where eight species are found. This statistic should be viewed with some scepticism,
however, since this geographical area has seen more specialized collecting than some other
areas, especially the highlands of South America.

The mexicana Complex

62. Hydraena tucumanica new species
(Figs. 49A,170)

Type-locality. - 20 kilometers S. Tucuman, Tucuman Province, Argentina.

Type-specimens. - The holotype male, allotype and one female paratype, all with identical
locality data, are deposited in USNM. Paul and Phyllis Spangler collected these specimens,
May 23, 1969.

Diagnosis. - The aedeagus must be used to reliably distinguish H. tucumanica males from
those of other species of the marginicollis Subgroup which also have serial elytral punctures
and small oval plaques.

Description. — Form: Elongate. Size: Holotype 1.40 mm long, 0.60 mm wide. Color: Dorsum of head black;
pronotum brown at margins, diffuse black macula on disc; elytra brown. Venter dark brown, nearly black. Legs with basal
0.50 of femur brown, remainder testaceous. Maxillae, antennae, inflexed margin of pronotum, and elytral epipleura
testaceous. Head: Length 0.22 mm; width 0.36 mm. Frons closely, moderately coarsely punctate, punctures separated by
about 0.50 puncture diameter, interstices shiny. Frontoclypeal suture slightly arcuate. Clypeus punctate in midline,
microreticulate laterally. Labroclypeal suture straight. Labrum bilobed, microreticulate, median emargination ended at
about midlength. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4 respectively: 0.22/0.10/0.18;
palpomere 4 asymmetrical, widest near distal 0.33. Mentum width equal length, densely, finely punctulate. Submentum
microreticulate. Genae shiny, foveolate laterally; posterior ridge absent. Postgena microreticulate. Thorax: Pronotum
length at midline 0.36 mm; maximum width (at midlength) 0.46 mm; sides margined, denticulate, slightly produced at
middle, slightly arcuate and slightly convergent to anterior angles, very slightly sinuate and slightly convergent to posterior
angles; anterior border 0.38 mm wide, straight and nearly perpendicular to midline in lateral 0.17, moderately arcuate to
rear in middle 0.66; posterior border 0.42 mm wide, very slightly arcuate to rear. Posterointernal foveolae absent.
Posteroexternal foveolae extremely shallow, nearly imperceptible. Interfoveolar depression shallow. Anteroexternal
foveolae well developed, each somewhat crescent shaped, extended across 0.25 width of anterior region of pronotum.
Transverse foveola absent. Disc moderately shiny, densely, deeply, moderately coarsely punctate, most punctures
separated by less than puncture width; each puncture with fine seta. Scintilla absent. Prosternum carinate, coxae separated
by thin carina, carina sinuate in lateral view. Mesosternum with internal and external carinae divergent from anterior to
posterior; median carina extended to base of intercoxal process; intercoxal process relatively narrow, apex blunt, width at
apex 0.50 distance between internal and median carinae. Metasternum with small oval plaques at posterior 0.20. Elytra:
Length 0.88 mm. Maximum width (at midlength) 0.60 mm. Disc moderately shiny, with 10 slightly irregular rows of deep,
moderately large punctures between suture and humeral callus; intervals not elevated, width about 0.50 puncture width;
interstices between punctures of row about 0.25 puncture width; each puncture with seta. Explanate margin narrow, ended
near posterior 0.20. Elytral border very finely serrate. Elytral apices slightly truncate in dorsal view; in posterior aspect
elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat,
nearly an equilateral triangle, posterior margin straight. Glabrous segments at apex produced. Tergum 7 emarginate at
apex. Legs: Protibia slightly arcuate, gradually increased in size from base to apex. Other legs without apparent
modification, slender. Genitalia: Aedeagus as illustrated (Fig. 49A)(1 examined).

Distribution. - (Fig. 170). Known only from the type-locality near Tucuman, Tucuman
Province, Argentina.

Etymology. - Latin, tucumanica , in reference to the known distribution.

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63. Hydraena quechua new species
(Figs. 49B,50B,170)

Type-locality. - Babahoyo, Los Rios Province, Ecuador.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. Paratypes (8 males, 7 females) from the same locality, collected by A. Langley and J.
Cohen, June 21, 1975, are deposited in USNM and PDP. Additional paratypes (10 males, 11
females) are deposited in USNM: 5.5 miles N. Nobel, Guayas Province, Ecuador, January 12,
1978, P. J. Spangler collector.

Diagnosis. - Readily distinguished from Hydraena jivaro, the only other Hydraena now
known from Ecuador, by smaller size (1.22 vs 1.48 mm) and black labrum of its adults. The
labrum of Hydraena jivaro is testaceous. The aedeagus must be studied to reliably distinguish
males of Hydraena quechua from other similarly sized and sculptured members of the
marginicollis Subgroup.

Description. — Form: Elongate. Size: Holotype 1.22 mm long, 0.54 mm wide. Color: Dorsum with labrum, clypeus
and frons black; pronotum with transverse black macula occupying area from anterior 0.28 to posterior 0.14, remainder
testaceous; elytra brown. Venter dark brown. Legs with basal 0.50 of femur brown, remainder testaceous. Maxillae,
inflexed. margin of pronotum, and elytral epipleura testaceous. Head: Length 0.20 mm; width 0.32 mm. Frons moderately
punctate, most punctures separated by puncture diameter, interstices shiny. Frontoclypeal suture slightly arcuate. Clypeus
shiny in midline, microreticulate and dull laterally. Labroclypeal suture straight. Labrum bilobed, median emargination
ending at midlength, microreticulate. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4 respectively:
0.22/0.10/0.16; palpomere 4 asymmetrical, greatest width near apical 0.33. Mentum width equal length, shiny, finely
punctulate. Submentum microreticulate. Genae shiny, foveolate laterally; posterior ridge absent. Postgena microreticulate.
Thorax: Pronotum length at midline 0.30 mm; maximum width (at midlength) 0.42 mm; sides margined, denticulate,
slightly produced at middle, slightly sinuate and slightly convergent to posterior angles; anterior border 0.36 mm wide,
straight and nearly perpendicular to midline in lateral 0.17, moderately arcuate to rear in middle 0.66; posterior border
0.38 mm wide, very slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal foveolae extremely shallow,
nearly imperceptible. Interfoveolar depression very shallow. Anteroexternal foveolae well developed, each somewhat
crescent shaped, extended across about 0.25 width of anterior region of pronotum. Transverse foveola absent. Disc shiny,
punctures slightly elongate, separated by puncture diameter near anterior and posterior borders, by twice this distance in
middle; punctures without apparent setae. Scintilla absent. Prosternum carinate; coxae separated by thin median carina,
carina sinuate line in lateral view. Mesosternum with internal and external carinae divergent from anterior to posterior;
median carina extended to base of intercoxal process; intercoxal process relatively narrow, apex blunt, width at apex 0.50
distance between internal and median carinae. Metasternum with well developed parallel plaques, separated by about
three times plaque width, 0.33 length of metasternum; each plaque about as wide as apex of intercoxal process. Elytra
Length 0.78 mm. Maximum width (at midlength) 0.54 mm. Disc shiny, with 10 rows of moderate sized punctures between
suture and humeral callus; intervals not elevated, width slightly less than puncture width, as are interstices between
punctures of a row; punctures with very fine seta. Explanate margin slightly developed, ended near posterior 0.20. Elytral
border from posterior 0.20 to apices finely serrate. Elytral apices somewhat truncate in dorsal view; viewed posteriorly,
elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat,
nearly an equilateral triangle, posterior margin straight. Glabrous segments at apex produced. Tergum 7 emarginate at
apex. Legs: Protibia slightly arcuate, increased gradually in size from base to apex. Other legs slender, apparently
unmodified. Genitalia: Aedeagus as illustrated (Fig. 49B)( 10 examined).

Natural History. - The specimens from Babahoyo were taken at ultraviolet light and most
are teneral, indicating pupation occurs in June, at least. The specimens from Nobol were
collected from a roadside pool (January).

Distribution. - (Figs. 50B,170). Presently known from Los Rios and Guayas Provinces,
Ecuador.

Etymology. - Noun in apposition, Latin in form, in reference to the Quechua Indians of
Ecuador.

Figs. 49A - D, Aedeagi of Hydraena holotypes. (A) H. tucumanica. (B) H. quechua. (C) H. limpidicollis. (D) H.
newtoni.

64. Hydraena limpidicollis new species
(Figs. 49C,170)

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168

Perkins

Type-locality. - Rio Frijoles, 4.1 miles NW Gamboa, Canal Zone, Panama.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. Paratypes (6 males, 7 females) from same locality are deposited in MCZ, USNM and
PDP. These specimens were collected by A. F. Newton, February 19, 1976.

Diagnosis. - Testaceous pronotum, small size, metasternal depression shape and aedeagus
serve as diagnostic features. Adults differ from those of Hydraena newtoni, the only other
species characterized by a testaceous pronotum, by the unicolorous elytra, smaller size, smaller
metasternal depression and aedeagal form.

Description. — Form: Ovate. Size: Holotype 1.00 mm long, 0.48 mm wide. Color: Pronotum testaceous, contrasting
markedly with dark brown head and elytra; legs, maxillae, deflexed margin of pronotum and elytral epipleura testaceous;
venter dark brown. Head: Length 0.18 mm; width 0.28 mm. Frons finely sparsely punctate, interstices one-two times
puncture diameter, shining. Frontoclypeal suture straight. Clypeus transversely depressed, shiny in middle, microreticulate
laterally. Labroclypeal suture arcuate. Labrum bilobed, median emargination ended at about midlength. Maxillary palpus
with following lengths (mm) of palpomeres 2, 3 and 4 respectively: 0.18/0.06/0.14; palpomere 4 very slightly
asymmetrical. Mentum wider than long, shiny, very finely punctulate. Submentum shiny, finely sparsely punctulate.
Genae shiny, foveolate laterally; posterior ridge absent. Postgena microreticulate. Thorax: Pronotum length at midline
0.24 mm; maximum width (at midlength) 0.34 mm; sides margined, denticulate, straight in middle, arcuate to anterior
angles, slightly sinuate to posterior angles; anterior border 0.30 mm wide, straight and nearly perpendicular to midline in
lateral 0.17, slightly arcuate to rear in middle 0.66; posterior border 0.30 mm wide, slightly arcuate to rear. Posterointernal
and posteroexternal foveolae absent. Anteroexternal foveolae well developed, crescent shaped, each occupying about 0.25
width of anterior region of pronotum. Transverse foveola absent. Disc shiny, finely, moderately sparsely punctate. Scintilla
absent. Prosternum carinate; coxae separated from carina by very thin shelf; carina sinuate line in lateral aspect.
Mesosternum with internal and external carinae divergent from anterior to posterior; median carina absent; intercoxal
process broad, width at apex equal distance between internal carina and midline. Metasternum with triangular depression
extended across posterior 0.50 in midline; plaques small, thin, on sides of triangular depression. Elytra: Length 0.62 mm.
Maximum width (at midlength) 0.48 mm. Disc shiny, with 10 indistinct rows of shallow punctures between suture and
humeral callus; intervals not elevated, width one-two times puncture diameter, like interstices between punctures of row;
punctures with very fine seta. Explanate margin narrow, ended near posterior 0.20; without apparent serrations. Elytral
apices, in dorsal aspect, rounded; in posterior aspect, elytral margin not elevated obliquely toward suture, not in form of
angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly an equilateral triangle; posterior margin straight.
Glabrous segments not produced. Legs: Protibia very slightly arcuate, other legs apparently unmodified, very slender.
Genitalia: Aedeagus as illustrated (Fig. 49C)(7 examined).

Natural History. - These specimens were extracted (using a Berlese funnel) from wet leaves
and flood debris collected at the margin of the Rio Frijoles.

Distribution. - (Fig. 170). Known only from the type-locality near Gamboa in the Canal
Zone, Panama.

Etymology. - Latin, limpid (transparent) plus collis (neck). Specimens of Hydraena
limpidicollis, when in alcohol, have the pronotum very transparent, so much so that the front
legs and posterior part of the head are visible through the marginal areas. The pronotum
becomes more opaque upon drying.

65. Hydraena newtoni new species
(Figs. 49D,170)

Type-locality. - Rio Frijoles, 4.1 miles NW Gamboa, Canal Zone, Panama.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. Paratypes (6 males, 10 females) from same locality are deposited in MCZ, USNM,
and PDP. These specimens were collected by A. F. Newton, February 19, 1976.

Diagnosis. - Distinguished from all Western Hemisphere Hydraena , except Hydraena
limpidicollis, by the testaceous pronotum; differs from the latter by (1) slightly larger size, (2)
presence of a diffuse light brown area on elytral disc, (3) broader, deeper, U-shaped
metasternal depression, (4) presence of a protibial tooth in males, and (5) aedeagal form

Western Hemisphere Hydraenidae

169

(Fig. 49D).

Description. — Form: Ovate. Size: Holotype 1.12 mm long, 0.50 mm wide. Color: Pronotum testaceous, head and
elytra dark brown except for diffuse light brown area on disc; venter dark brown; legs, palpi, mentum and apex of abdomen
testaceous. Head: Length 0.20 mm; width 0.29 mm. Frons finely moderately sparsely punctate, interstices 0. 5-2.0 times
puncture diameter, shining. Frontoclypeal suture straight. Clypeus transversely depressed, shiny in middle, microreticulate
laterally. Labroclypeal suture arcuate. Labrum bilobed, median emargination ended at about midlength. Maxillary palpus
with following lengths (mm) of palpomeres 2, 3 and 4 respectively: 0.19/ 0.08/0.16; palpomere 4 very slightly
asymmetrical. Mentum wider than long, shiny, very finely punctulate. Submentum shiny, finely sparsely punctulate.
Genae shiny, foveolate laterally; posterior ridge absent. Postgena microreticulate. Thorax: Pronotum length at midline
0.30 mm; maximum width (at midlength) 0.35 mm; sides margined, denticulate, parallel just before middle, arcuate to
anterior angles, slightly sinuate and convergent to posterior angles; anterior border 0.32 mm wide, straight and nearly
perpendicular to midline in lateral 0.17, slightly arcuate to rear in middle 0.66; posterior border 0.33 mm wide, slightly
arcuate to rear. Posterointernal and posteroexternal foveolae absent. Anteroexternal foveolae well developed, cresent
shaped, each extended across about 0.25 width of anterior region of pronotum. Transverse foveola absent. Disc shiny,
finely, moderately sparsely punctate. Scintilla absent. Prosternum carinate; coxae separated from carina by very thin shelf;
carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior;
median carina absent; intercoxal process broad, width at apex equal distance between internal carina and midline.
Metasternum with deep, wide U-shaped depression extended across posterior 0.50 in midline; plaques small, thin, at border
of U-shaped depression. Elytra: Length 0.70 mm; maximum width (at midlength) 0.50 mm. Disc moderately convex,
shiny, with 10 indistinct rows of shallow punctures between suture and humeral callus; intervals not elevated, width
one-two times puncture diameter as are interstices between punctures of row; punctures with very fine but quite evident
seta. Explanate margin narrow, ending near posterior 0.20; without apparent serrations. Elytral apices, in dorsal aspect,
rounded; viewed posteriorly, elytral margin not elevated obliquely toward suture, not in form of angle with opposite
elytron. Abdomen: Intercoxal segment flat, nearly an equilateral triangle; posterior margin straight. Glabrous segments
not produced. Legs: Protibia slightly arcuate, inner surface slightly enlarged and with tooth near apical 0.33; other legs
very slender, apparently unmodified. Genitalia: Aedeagus as illustrated (Fig. 49D)(7 examined).

Natural History. - These specimens were extracted (using a Berlese funnel) from wet leaves
and flood debris collected at the margin of the Rio Frijoles. Also found in this material were
specimens of Hydraena limpidicollis and H. pontequula.

Distribution. - (Fig. 170). Known only from the type-locality near Gamboa in the Canal
Zone, Panama.

Etymology. - I am pleased to dedicate this attractive and unusual new species to Alfred F.
Newton, Jr., who collected the only specimens known to date.

66. Hydraena guatemala new species
(Figs. 51A,170)

Type-locality. - 17 miles E. Escuintla, Escuintla, Guatemala.

Type-specimen. - The holotype male (unique) is deposited in USNM. Paul J. Spangler
collected this specimen, July 8, 1965.

Diagnosis. - The aedeagus should be used to distinguish Hydraena guatemala males from
those of other species of the marginicollis Subgroup which also have small oval plaques and are
relatively small in body length (about 1.26 mm).

Description. — Form: Elongate Size: Holotype 1 .26 mm long, 0.52 mm wide. Color: Head with dorsal surface dark
brown, nearly black; labrum dark brown; maxillary palpi and antennae testaceous. Pronotum testaceous at anterior and
posterior 0.20, dark brown in middle 0.60; sides slightly lighter than disc. Elytra brown. Ventral surface dark brown except
legs, elytral epipleura and inflexed margin of pronotum brown. Head: Length 0.18 mm. Width 0.34 mm. Frons moderately
punctate, interstices equal to or slightly less than puncture diameter; surface shining. Frontoclypeal suture straight.
Clypeus microreticulate at sides, shiny in middle. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed,
microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary
palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.24/0.10/0.16; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface slightly
arcuate, median more markedly arcuate; palpomere 4 widest near apical 0.33. Mentum wider than long, surface shining,
finely and sparsely punctulate. Submentum finely, rather sparsely punctulate. Genae shining; lateral area of each gena
with well developed foveola; posterior ridge absent. Postgena with punctation slightly larger than that of submentum. Last

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170

Perkins

Figs. 50A - B, Geographical distributions. (A) Gymnochthebius peruvianus • , G. bartyrae ★ and Parhydraenida
pentatenkta ■ . (B) Hydraena quechua • , H. premordica ★ , H. jivaro A and H. anisonycha ■ .

five antennomeres pubescent. Eyes slightly less than 0.33 interocular distance in width. Thorax: Pronotum length at
midline 0.32 mm; maximum width (at approximately midlength) 0.42 mm; sides margined, denticulate; sides relatively
slightly produced at middle, straight and very slightly convergent to anterior angle, very slightly concave and slightly
convergent to posterior; anterior border 0.38 mm wide, straight and nearly perpendicular to midline in lateral 0.25,
moderately arcuate to rear in middle 0.50; posterior border 0.40 mm wide, slightly arcuate to rear. Posterointernal
foveolae absent. Posteroexternal foveola absent. Interfoveolar depression absent. Anteroexternal foveolae well developed,
each foveola somewhat crescent shaped, extended across slightly less than 0.33 width of anterior region of pronotum.
Transverse foveola absent. Disc shining, punctures fine, separated by one-three times puncture diameter; most punctures
with seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as
very short spine; coxae separated by thin, median carina, latter sinuate line in lateral aspect. Mesosternum with internal
and external carinae divergent from anterior to posterior ; median carina extended to base of intercoxal process;
intercoxal process relatively narrow, sides tapered, apex blunt, width at apex 0.33 distance between internal and median
carinae. Metasternum with plaques slightly developed, of small ovals at posterior 0.20; width of each plaque subequal to
width of intercoxal process at its apex; plaques separated posteriorly by approximately twice plaque width; plaques flat
in cross section. Elytra: Length 0.78 mm. Maximum width (at midlength) 0.52 mm. Surface shining, disc with 10 rows
of punctures between suture and humeral callus; most punctures round; intervals not elevated; width approximately
equal to puncture diameter, as are interstices between adjacent punctures of row; each puncture with seta. Explanate
margin quite narrow, ended near posterior 0.20, with fine serrations in posterior 0.33; serrations closer near apices.
Elytral apices, in dorsal aspect, truncate; in posterior aspect, elytral margin extended obliquely toward suture, in form
of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous
segments at apex moderately produced. Segment 7 emarginate at apex. Legs: Profemur with minute tubercle on inner
surface near midlength. Protibia enlarged gradually from base to apex, slightly arcuate, very slightly expanded on inner
surface near base. Metatibia nearly parallel sided in apical 0.66. Genitalia: Aedeagus as illustrated (Fig. 5 1 A)( 1
examined).

Distribution. - (Fig. 170). Presently known only from the type-locality near Escuintla,
Guatemala.

Etymology. - Noun in apposition, Latin in form, guatemala, in reference to the known
distribution.

Western Hemisphere Hydraenidae

171

67. Hydraena haitensis new species

(Figs. 5 IB, 170)

Type-locality. - Etang Lachaux, SW peninsula, under 1000 feet, Haiti.

Type-specimen. - The holotype male (unique) is deposited in MCZ. P.J. Darlington
collected this specimen, October 26-27 , 1934.

Diagnosis. - The geographical distribution (Haiti), small size (about 1.28 mm), and
moderately developed plaques, which are separated by the greatest width of a plaque, are of
some aid in assigning specimens to this species. The aedeagus must be used to reliably
distinguish males of this species from others in the marginicollis Subgroup which are of
approximately the same body size and plaque configuration.

Description. — Form: Elongate. Size: Holotype 1.28 mm long, 0.52 mm wide. Color: Head with dorsal surface dark
brown, nearly black; labrum dark brown; maxillary palpi brown; antennae brown. Pronotum dark brown, nearly black,
except for narrow, testaceous border at anterior and posterior margins. Elytra brown. Ventral surface dark brown except
legs, elytral epipleura, apex of abdomen and inflexed margin of pronotum brown. Head: Length 0.20 mm. Width 0.34 mm.
Frons moderately punctured, interstices equal to or slightly greater than puncture diameter; surface shining. Frontoclypeal
suture straight. Clypeus finely microreticulate at sides, shining in midline. Labroclypeal suture arcuate in dorsal aspect.
Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of
labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively; 0.20/0.08/0.16;
palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4
with lateral suface nearly straight, median surface rather markedly arcuate; palpomere 4 widest slightly past midlength.
Mentum wider than long, surface shining, finely and sparsely punctulate. Submentum microreticulate. Genae shining:
lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with fine, contiguous punctation.
Last five antennomeres pubescent. Eyes slightly less than 0.20 interocular distance in width. Thorax: Pronotum length at
midline 0.34 mm; maximum width (at anterior 0.33 mm) 0.44 mm; sides margined, denticulate; sides relatively weakly
produced at anterior 0.33, slightly arcuate and slightly convergent to anterior angle, sinuate and convergent to posterior;
anterior border 0.38 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in
middle 0.50; posterior border 0.42 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal
foveola absent. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across slightly
less than 0.33 width of anterior region of pronotum. Transverse foveola absent. Disc shining, punctures fine, separated by
puncture diameter; most punctures with distinctive seta extended above cuticle in dry specimens. Scintilla absent.
Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin, median carina; carina
sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median
carina extended to base of intercoxal process; intercoxal process relatively narrow, sides tapered; apex blunt, width at apex
0.50 distance between internal and median carinae. Metasternum with plaques well developed, triangular; plaques 0.33
length of metasternum in midline; width of each plaque subequal to width of intercoxal process at its apex; plaques
separated posteriorly by approximately plaque width; plaques flat in cross section. Elytra: Length 0.84 mm. Maximum
width (at midlength) 0.52 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows
quite regular; most punctures round; intervals not elevated, width approximately equal to 0.50 puncture diameter, as are
interstices between adjacent punctures of a row; each puncture with seta. Explanate margin quite narrow, ended near
posterior 0.20, with fine, well separated serrations in apical 0.33; serrations closer near apices. Elytral apices, in dorsal
aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture in form of angle with
opposite elytron. Abdomen: Intercoxal segment flat, longer than wide, posterior margin straight. Glabrous segments at
apex moderately produced. Segment 7 emarginate at apex. Legs: Protibia arcuate. Genitalia: Aedeagus as illustrated
(Fig. 5 1 B)( 1 examined).

Distribution. - (Fig. 170). Presently known only from Haiti.

Etymology. - Latin, haitensis , in reference to the known geographical distribution.

68. Hydraena mexicana new species

(Figs. 42A,51C,170)

Type-locality. - Four miles N. Bochil, Chiapas, Mexico.

Type-specimens. - The holotype male is deposited in USNM. My wife Maureen and I
collected this specimen, May 28, 1974. The allotype, collected by Hugh B. Leech, is deposited

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172

Perkins

with the holotype and has the following data: Clear stream at Palitla, 5 mi. N. of
Tamazunchale, 22-XII-1948, San Lusi Potosi, Mexico. Paratypes (5) are listed in the
appendix.

Diagnosis. - The plaques are elongate, parallel, separated from one another by two-three
times the width of a plaque. The aedeagus must be studied to reliably discriminate males of
Hydraena mexicana from others in the marginicollis Subgroup with similar plaque
configuration.

Description. — Form: Elongate. Size: Holotype 1.42 mm long, 0.58 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum with subquadrate, dark brown
macula; lateral areas testaceous. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed
margin of pronotum brown. Head: Length 0.18 mm. Width 0.34 mm. Frons moderately punctured, interstices equal to or
slightly greater than puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus finely punctulate.
Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median
emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.24/0.14/0.16; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface very slightly arcuate, median surface
moderately arcuate; palpomere 4 widest near midlength. Mentum length equal width, surface markedly shining, punctures
fine and sparse. Submentum punctation similar to mentum. Genae moderately elevated, shining; lateral area of each gena
with well developed foveola; posterior ridge absent. Postgena with punctation much finer and closer than that of
submentum. Last five antennomeres pubescent. Eyes slightly greater than 0.25 interocular distance in width. Thorax:
Pronotum length at midline 0.36 mm; maximum width (at approximately midlength) 0.44 mm; sides margined,
denticulate; sides relatively slightly produced at middle, slightly arcuate and slightly convergent to anterior angle, slightly
sinuate and slightly convergent to posterior; anterior border 0.38 mm wide, straight and nearly perpendicular to midline in
lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.40 mm wide, slightly arcuate to rear.
Posterointernal foveolae absent. Posteroexternal foveola delimited by very shallow depression with punctation somewhat
closer than that of disc. Interfoveolar depression slightly developed. Area between external foveolae weakly elevated.
Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across slightly less than 0.33
width of anterior region of pronotum. Transverse foveola slightly developed, with punctures closer together than punctures
on disc. Disc shining, punctures fine, separated by one-two times puncture diameter; most punctures with distinctive seta
extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short
spine; coxae separated by thin, median carina, latter sinuate line in lateral aspect. Mesosternum with internal and external
carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process
moderately broad, sides tapered, apex blunt, width at apex slightly greater than 0.50 distance between internal and median
carinae. Metasternum with plaques moderately developed, straight, parallel; plaques 0.40 length of metasternum in
midline; width of each plaque subequal to width of intercoxal process at its apex; plaques separated posteriorly by
approximately twice plaque width; plaques on side of median depression, sloped very slightly toward midline. Elytra:
Length 0.86 mm. Maximum width (at midlength) 0.58 mm. Surface shining, disc with 10 rows of punctures between
suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width approximately equal to
nearly twice puncture diameter, as are interstices between adjacent punctures of a row; punctures each with seta.
Explanate margin quite narrow, ended near posterior 0.12, with prominent serrations in posterior 0.33; serrations smaller
near apices. Elytral apices, in dorsal aspect, weakly truncate; in posterior aspect, elytral margin elevated obliquely toward
suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly an equilateral triangle, posterior
margin straight. Glabrous segments at apex moderately produced. Tergum 7 emarginate at apex; sternum with small,
circular excavation on inner surface. Legs: Protibia with inner surface straight, lateral surface slightly arucate. Metatibia
markedly enlarged in basal 0.17, gradually enlarged for remainder of length. Genitalia: Aedeagus as illustrated
(Fig. 51C)(5 examined).

Natural History. - Refer to H. splecoma .

Distribution. - (Figs. 42A,170). Presently known from the Mexican states of San Luis
Potosi, Veracruz and Chiapas.

Etymology. - Adjective, Latin form, mexicana , in reference to the geographical
distribution.

69. Hydraena perkinsi Spangler
(Figs. 51D,170)

Hydraena perkinsi Spangler, 1980:331 (holotype male in USNM; type-locality: Quenado de Pineda, Cuba).

Western Hemisphere Hydraenidae

173

Diagnosis. - Adults are moderately large, about 1 .48 mm long, with plaques subtriangular
in shape. The aedeagus must be used to differentiate Hydraena perkinsi males from those of
other members of the marginicollis Subgroup of similar body size and plaque configuration.

Figs. 51 A - D, Aedeagi of Hydraena holotypes. (A) H. guatemala. (B) H. haitensis. (C) H. mexieana. (D) H. perkinsi.

Quaest. Ent., 1980, 16 (1,2)

174

Perkins

Description. — Form: Elongate. Size: Holotype 1.48 mm long, 0.64 mm wide. Color: Head with dorsum black,
venter dark brown, palpi and antennae testaceous. Pronotum with anterior and posterior 0.25 testaceous, middle 0.50 with
black macula, macula lighter near sides. Elytra brown. Venter dark brown. Legs, inflexed margin of pronotum and elytral
epipleura testaceous. Head: Length 0.22 mm, width 0.36 mm. Frons moderately densely, moderately coarsely punctate,
most punctures separated by less than puncture diameter. Frontoclypeal suture slightly arcuate. Clypeus shiny, very finely
punctulate in middle, microreticulate laterally. Labroclypeal suture straight. Labrum microreticulate, bilobed, median
emargination ended near midlength. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4 respectively:
0.26/0.12/0.18; palpomere 4 asymmetrical, widest near distal 0.33. Mentum width equal length, punctulate,
microreticulate. Submentum microreticulate. Genae shiny, foveolate laterally. Postgena microreticulate. Thorax:
Pronotum length at midline 0.36 mm; maximum width (slightly before midlength) 0.48 mm; sides margined, finely
denticulate, very slightly produced, straight and slightly convergent to anterior angles, slightly sinuate and slightly
convergent to posterior angles; anterior border 0.40 mm wide, straight and nearly perpendicular to midline in lateral 0.20,
slightly arcuate in middle 0.60; posterior border very slightly arcuate to rear. Posterointernal and posteroexternal foveolae
absent. Anteroexternal foveolae well developed, each extended across 0.25 width of anterior region of pronotum. Disc
shiny, moderately densely, moderately coarsely punctate, most punctures separated by less than puncture diameter;
punctures without apparent seta. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine;
coxae separated by thin median carina, latter sinuate in lateral view. Mesosternum with internal and external carinae
divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively
narrow, apex blunt, width at apex 0.50 distance between internal and median carinae. Metasternum with plaques well
developed, flat, 0.50 length of metasternum, median margins parallel, lateral margins slightly convergent anteriorly; each
plaque tapered from posterior to anterior, width at base subequal width of intercoxal process; plaques separated at base by
twice plaque width. Elytra: Length 0.94 mm; Maximum width (at midlength) 0.64 mm. Disc shiny, with 10 rows of
moderately large punctures between suture and humeral callus; intervals not elevated, width subequal puncture diameter,
interstices between punctures of row slightly less. Explanate margin slightly developed, ended near posterior 0.20, border
finely serrate in posterior 0.33. Elytral apices slightly dehiscent in dorsal view; viewed posteriorly, elytral margin elevated
obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly an equilateral
triangle; posterior margin straight. Glabrous segments at apex produced. Tergum 7 emarginate at apex. Legs: Protibia
slightly expanded and with two rows of short spines in distal 0.33. Other legs slender, unmodified. Genitalia: Aedeagus as
illustrated (Fig. 5 1 D)( 1 examined).

Variation. - Females lack the protibial modifications seen in males.

Distribution. - (Fig. 170). Cuba.

The jivaro Complex

70. Hydraena grouvellei d’Orchymont
(Figs. 52A.171B)

Hydraena grouvellei d’Orchymont, 1923:35 (holotype depository uncertain; type-locality: “Mexique (tabacs)”).

According to d’Orchymont (1923) the holotype is in the Paris Museum. Through the
courtesy of that institution I have been able to study a male paratype. There is a possibility that
further search will reveal the holotype, therefore I am not designating a lectotype at this time.

Diagnosis. - Distinguished from other members of the marginicollis Subgroup by the
extremely shiny dorsum and the arcuate, carinate plaques. The punctures on the pronotum are
very fine and widely spaced, interstices being three-six times puncture diameter. The elytra are
truncate in males (I have not seen females).

Description. — Form: Elongate-oval. Size: The paratype male 1 have studied is 1.43 mm long, 0.64 mm wide.
Color: Head with dorsal surface dark brown, black near eyes; labrum brown; maxillary palpi and antennae testaceous.
Pronotum dark brown except narrow testaceous anterior and posterior border. Elytra brown. Ventral surface dark brown
except legs, elytral epipleura and inflexed margin of pronotum, light brown. Head: Length 0.19 mm. Width 0.36 mm.
Frons finely and sparsely punctate, interstices two-four times puncture diameter; surface shining. Frontoclypeal suture
slightly arcuate to rear. Clypeus finely microreticulate at sides, impunctate and shining in midline. Labroclypeal suture
arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:

Western Hemisphere Hydraenidae

175

0.28/0.12/0.20; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface straight, median surface arcuate; palpomere 4 widest at anterior 0.33.
Mentum wider than long, surface shining, finely punctulate. Submentum microreticulate. Genae shining; lateral area of
each gena with well developed foveola; posterior ridge absent. Postgena microreticulate. Last five
antennomeres pubescent. Eyes 0.20 interocular distance in width. Thorax: Pronotum length at midline 0.42 mm;
maximum width (at approximately midlength) 0.52 mm; sides margined, not denticulate in anterior 0.50, extremely
finely denticulate in posterior 0.50; sides relatively slightly produced at middle, very slightly arcuate and slightly
convergent to anterior angle, very slightly arcuate and slightly convergent to posterior; anterior border 0.44 mm wide,
straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border

O. 50 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal foveola absent. Anteroexternal
foveolae well developed, each foveola somewhat crescent shaped, extended across slightly less than 0.20 width of
anterior region of pronotum. Transverse foveola absent. Disc brilliantly shining, punctures extremely fine, separated by
three-six times puncture diameter; punctures without distinctive setae extended above cuticle in dry specimens. Scintilla
absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin, median carina;
carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to
posterior; median carina extended to base of intercoxal process; intercoxal process relatively narrow, sides tapered, apex
blunt, width at apex 0.50 distance separating internal and median carinae. Metasternum with plaques well developed,
carinate, markedly arcuate, 0.50 length of metasternum in midline; plaques separated posteriorly by approximately six
times plaque width. Elytra: Length 0.93 mm. Maximum width (at midlength) 0.64 mm. Surface shining, disc with 10
rows of punctures between suture and humeral callus, rows quite regular; most punctures round; intervals not elevated,
width approximately equal to twice puncture diameter, as are interstices between adjacent punctures of a row;
punctures without perceptible setae. Explanate margin moderately developed, ended near posterior 0.10, with extremely
fine, well separated serrations along anterior 0.66, quite large and distinct in posterior 0.33; serrations obsolete near
apices. Elytral apices, in dorsal aspect, truncate; in posterior aspect, elytral margin elevated obliquely toward suture, in
form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly an equilateral triangle, posterior margin
straight. Glabrous segments at apex well produced. Tergum 7 emarginate at apex; sternum with oval excavation on
inner surface in midline. Legs: Profemur with minute tubercle on inner surface near midlength. Protibia excavate on
inner surface near apex. Metatibia enlarged gradually from base to apex. Genitalia: Aedeagus as illustrated
(Fig. 52A)(2 examined).

Distribution. - (Fig. 17 IB). Exact location within Mexico uncertain. The single specimen I
have seen in addition to the paratype described above is also labelled “Mexique, tabacs”, which
is the only information given by d’Orchymont (1923) in the original description.

7 1 . Hydraena premordica new species
(Figs. 50B,52B,171B)

Type-locality. - Mayaro, Trinidad.

Type-specimens. - The holotype male is deposited in MCZ. This specimen was collected by

P. J. Darlington, April 28, 1929. The allotype, which is deposited in BMNH, has the following
data: British Guiana, Kanuku Mts., Rupununi, 61-2-21, T. Clay. Paratypes (24) have the same
data as the allotype and are deposited in BMNH, USNM and PDP.

Diagnosis. - Males are instantly recognized by the markedly truncate elytra; each elytron
has the posterior margin sinuate. Both sexes have a few punctures on the elytral disc random,
not in serial rows as are the remaining punctures. The elytra of females are slightly angulate on
the sides in the posterior, but the apices are not truncate. Plaques are well developed,
non-carinate.

Description. — Form: Elongate-oval. Size: Holotype 1.76 mm long, 0.76 mm wide. Color: Head with dorsal surface
brown, dark brown near eyes; labrum brown; antennae testaceous. Pronotum testaceous at anterior and posterior 0.20,
dark brown in middle 0.60. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of
pronotum brown. Head: Length 0.20 mm. Width 0.42 mm. Frons moderately punctured, interstices generally less than
puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus finely punctulate. Labroclypeal suture straight
in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpi missing from specimen. Mentum wider than long, surface moderately
shining, microreticulate. Submentum microreticulate. Genae shining; lateral area of each gena with well developed
foveola; posterior ridge absent. Postgena with microreticulation similar to that of submentum. Last five

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176

Perkins

antennomeres pubescent. Eyes slightly less than 0.20 interocular distance in width. Thorax: Pronotum length at midline
0.46 mm; maximum width (at approximately midlength) 0.58 mm; sides margined, denticulate; sides moderately
produced at middle, slightly arcuate and convergent to anterior angle, slightly sinuate and convergent to posterior;
anterior border 0.44 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear
in middle 0.50; posterior border 0.52 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal
foveola absent. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across slightly
less than 0.33 width of anterior region of pronotum. Transverse foveola not developed, punctures in this area closer
together than punctures on disc. Disc moderately shining, punctures fine, separated by thin walls near anterior and
posterior borders, by puncture diameter in middle; most punctures with distinctive seta extended above cuticle in dry
specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by
thin, median carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent
from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively narrow,
sides nearly parallel, apex blunt, width at apex 0.33 distance between internal and median carinae. Metasternum with
plaques well developed, straight, convergent moderately from posterior to anterior; plaques 0.50 length of metasternum
in midline; width of each plaque subequal to width of intercoxal process at its apex; plaques separated posteriorly by
approximately twice plaque width; plaques flat in cross section. Elytra: Length 1.04 mm. Maximum width (at
midlength) 0.76 mm. Surface shining, anterior 0.66 with random punctures gradually arranged into rows in posterior
0.33 of elytra; most punctures round; interstices generally less than puncture diameter; most punctures with seta.
Explanate margin quite narrow, ended at apices, with extremely fine, well separated serrations along entire margin.
Elytral apices, in dorsal aspect, truncate, apex of each elytron sinuate line; in posterior aspect, elytral margins together
in form of a half oval. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous segments
at apex moderately produced. Tergum 7 emarginate at apex; sternum with oval excavation on inner surface in midline.
Legs: Profemur with oblique carina on inner surface near basal 0.33. Protibia weakly arcuate; posterior surface with
prominent, tooth-like expansion at apical 0.33. Metafemur relatively narrow. Metatibia thin, parallel sided. Genitalia:
Aedeagus as illustrated (Fig. 52B)(2 examined).

Natural History. - Specimens from the Kanuku Mountains of Guyana have the label
notation: “debris edge of forest creek”.

Distribution. - (Figs. 50B,171B). Presently known from Trinidad and Guyana.

Etymology. - Latin, premordica (bitten off at the end). This name refers to the truncate
elytra of males.

72. Hydraena jivaro new species
(Figs. 50B,52C,171B)

Type-locality. - 3 kilometers S. Tena, Napo Province, Ecuador.

Type-specimens. - The holotype male, allotype and one female paratype are deposited in
USNM. These specimens were collected by P. J. Spangler and D. R. Givens, May 13, 1977.

Diagnosis. - Readily distinguished from Hydraena quechua adults, the only other
Hydraena now known from Ecuador, by larger size (1.48 vs 1.22 mm) and testaceous labrum.
The labrum of Hydraena quechua adults is black. Separation from other similarly sized and
sculptured members of the marginicollis Subgroup, however, must be based on the aedeagus.

Description. — Form: Elongate. Size: Holotype 1.48 mm long, 0.64 mm wide. Color: Dorsum with labrum
testaceous; clypeus brown in middle, testaceous laterally; frons black; pronotum with transverse black macula extended
from anterior 0.28 to posterior 0.14, remainder testaceous; elytra brown. Venter dark brown. Legs with basal 0.50 of femur
brown, remainder testaceous. Maxillae testaceous. Head: Length 0.22 mm; width 0.36 mm. Frons moderately punctate,
most punctures separated by puncture diameter, interstices shining. Frontoclypeal suture slightly arcuate. Clypeus shiny in
midline, microreticulate and dull laterally. Labroclypeal suture straight. Labrum bilobed, median emargination ended at
midlength, microreticulate. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4 respectively:
0.27/0.10/0.18; palpomere 4 asymmetrical, greatest width near apical 0.33. Mentum width equal length, shiny, finely
punctulate. Submentum microreticulate. Genae shiny, foveolate laterally; posterior ridge absent. Postgena microreticulate.
Thorax: Pronotum length at midline 0.40 mm; Maximum width (at midlength) 0.50 mm; sides margined, denticulate,
slightly produced at middle, slightly arcuate and slightly convergent to anterior angles, very slightly sinuate and slightly
convergent to posterior angles; anterior border 0.40 mm wide, straight and nearly perpendicular to midline in lateral 0.17,
moderately arcuate to rear in middle 0.66; posterior border 0.46 mm wide, very slightly arcuate to rear. Posterointernal
foveolae absent. Posteroexternal foveolae extremely shallow, nearly imperceptible. Interfoveolar depression shallow.
Anteroexternal foveolae well developed, each somewhat crescent shaped, extended about 0.25 width of anterior region of

Western Hemisphere Hydraenidae

Figs. 52 A - D, Aedeagi of Hydraena species. (A) H. grouvellei, paratype. (B) H. premordica , holotype. (C) H.
holotype. (D) H. anaphora , holotype.

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178

Perkins

pronotum. Transverse foveola absent. Disc shiny, punctures slightly elongate, separated by thin walls near anterior and
posterior borders, by two-three times puncture width in middle; punctures without apparent setae. Scintilla absent.
Prosternum carinate; coxae separated by thin median carina, latter sinuate in lateral aspect. Mesosternum with internal
and external carinae divergent from anterior to posterior; median carina extended to base of intercoxal process;
intercoxal process relatively narrow, apex blunt, width at apex 0.50 distance between internal and median carinae.
Metasternum with well developed parallel plaques, separated by twice plaque width, 0.50 length of metasternum; each
plaque about as wide as apex of intercoxal process. Elytra: Length 0.96 mm; maximum width (at midlength) 0.64 mm.

. Disc shiny, with 10 rows of moderate sized punctures between suture and humeral callus; intervals not elevated, width
slightly less than puncture width, as are interstices between punctures of a row; punctures with very fine seta. Explanate
margin moderately developed, ended near posterior 0.20. Elytral border from posterior 0.20 to apices finely serrate.
Elytral apices nearly truncate in dorsal view; viewed posteriorly, elytral margin elevated obliquely toward suture, in
form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly equilateral triangle, posterior margin
straight. Glabrous segments at apex produced. Tergum 7 emarginate at apex. Legs: Profemur with small carina on inner
surface near basal 0.33. Protibia excavate on inner surface from basal 0.25 to apex, small tooth at base of excavation.
Other legs apparently unmodified. Genitalia: Aedeagus as illustrated (Figure 52C) (1 examined).

Distribution. - (Figs. 50B,171B). Known only from the typelocality near Tena in Napo
Province of Ecuador.

Etymology. - Noun in apposition, Latin in form, jivaro, in reference to the Jivaro Indians of
Ecuador.

73. Hydraena anaphora new species
(Figs. 52D.171B)

Type-locality. - Cuyaba, Matto Grosso, Brazil.

Type-specimen. - The holotype male (unique) is deposited in CMP. The collector and date
are unknown.

Diagnosis. - The arcuate plaques which are elevated in the anterior, plus non-modified
metatibiae of males serve to distinguish H. anaphora adults from other members of the
marginicollis Subgroup. Plaques are widest at their bases, about as wide as the mesosternal
process; three times this distance separates the plaques at their bases. Each plaque narrows
anteriorly to form an elevated, subcariniform prominence.

Description. — Form: Elongate. Size: Holotype 1 .60 mm long, 0.64 mm wide. Color: Head with dorsal surface dark
brown, nearly black adjacent to eyes; labrum testaceous; maxillary palpi brown; antennae testaceous. Pronotum testaceous
at anterior and posterior 0.20, dark brown in middle 0.60; sides slightly lighter than disc. Elytra brown. Ventral surface
dark brown except legs, elytral epipleura and inflexed margin of pronotum brown. Head: Length 0.20 mm. Width
0.36 mm. Frons moderately punctured, interstices equal to or slightly greater than puncture diameter; surface shining.
Frontoclypeal suture straight. Clypeus finely punctulate. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed,
microreticulate, each lobe symmetrical arc; median emargination ended slightly above midlength of labrum. Maxillary
palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.26/ 0.12/0.20; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly
straight in basal 0.33, arcuate in apical 0.66, median surface more markedly arcuate; tarsomere 4 widest slightly past
midlength. Mentum wider than long, surface moderately shining, finely and sparsely punctulate. Submentum
microreticulate. Genae shining; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with
microreticulation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly greater than
0.25 interocular distance in width. Thorax: Pronotum length at midline 0.40 mm; maximum width (at approximately
midlength) 0.48 mm; sides margined, denticulate; sides moderately produced at middle, slightly arcuate and slightly
convergent to anterior angle, sinuate and convergent to posterior; anterior border 0.40 mm wide, straight and nearly
perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.44 mm. wide,
slightly arcuate to rear. Posterointernal foveolae absent. Interfoveolar depression moderately developed. Posteroexternal
foveolae absent. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended across slightly
less than 0.33 width of anterior region of pronotum. Transverse foveola not developed, punctures in this area somewhat
closer together than punctures on disc. Disc shining, punctures fine, separated by one-three times puncture diameter; most
punctures without distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina
produced anteriorly as very short spine; coxae separated by thin, median carina; carina sinuate line in lateral aspect.
Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to base of
intercoxal process; intercoxal process relatively narrow, sides nearly parallel in apical 0.50, apex blunt, width at apex 0.33

Western Hemisphere Hydraenidae

179

distance between internal and median carinae. Metasternum with plaques well developed, slightly arcuate, convergent
from posterior to anterior; plaques 0.50 length of metasternum in midline; greatest width of each plaque subequal to
width of intercoxal process at its apex; plaques separated posteriorly by approximately three times plaque width; each
plaque narrowed to thin elevated, subcariniform prominence at anterior. Elytra: Length 0.96 mm. Maximum width (at
midlength) 0.64 mm. surface shining, disc with 10 rows of punctures between suture and humeral callus, rows
somewhat irregular; most punctures round; intervals not elevated, width approximately equal to puncture diameter, as
are interstices between adjacent punctures of row; each puncture with seta. Explanate margin quite narrow, ended near
posterior 0.20, with extremely fine, well separated serrations along entire margin; serrations somewhat closer near
apices. Elytral apices, in dorsal aspect, truncate; in posterior aspect, elytral margin elevated obliquely toward suture, in
form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight.
Glabrous segments at apex moderately produced. Tergum 7 emarginate at apex; sternum with a round excavation on
inner surface in midline. Legs: Profemur with oblique, cariniform protuberance on inner surface near basal 0.33.
Protibia very slightly arcuate; inner surface expanded in apical 0.33. Metafemur broad; anterior surface markedly
arcuate; posterior sinuate. Metatibia slender, nearly parallel sided in apical 0.66. Genitalia: Aedeagus as illustrated
(Fig. 52D) (1 examined).

Distribution. - (Fig. 17 IB). Presently known only from the type-locality in Matto Grosso,
Brazil.

Etymology. - Latin, anaphora (a rising). Named in reference to the raised anterior region
of the plaques.

74. Hydraena hyalina new species
(Figs. 64A,92A,171B)

Type-locality. - 32 km. SW Calabozo, Guarico, Venezuela.

Type-specimens. - The holotype male is deposited in USNM. The allotype, also deposited in
USNM, has the following data: 15 km. S. Calabozo, Guarico, Venezuela. These specimens
were collected by Paul and Phyllis Spangler, February 9-11, 1969. Paratypes (70) are listed in
the appendix.

Diagnosis. - This species cannot be adequately characterized on the basis of external
features at this time. The aedeagus must be studied to reliably distinguish males of Hydraena
hyalina from others in the marginicollis Subgroup. The pronotum is relatively coarsely
punctate and has very shallow posterointernal foveolae, which would indicate that this species
should be placed in the lee chi Group. The aedeagus, however, appears to be most similar to
males of the marginicollis Group, hence its placement here.

Description. — Form: Elongate. Size: Holotype 1.44 mm long, 0.56 mm wide. Color: Head with dorsum and
labrum black; maxillary palpi and antennae testaceous. Pronotum testaceous at anterior and posterior 0.25, black in
middle 0.50; black of disc blending into brown at sides. Elytra brown. Ventral surface dark brown except legs, elytral
epipleura and inflexed margin of pronotum brown. Head: Length 0.20 mm. Width 0.36 mm. Frons moderately punctured,
interstices equal to or slightly less than puncture diameter; surface shining. Frontoclypeal suture, straight. Clypeus finely
punctulate. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc;
median emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.20/0.08/0.16; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface weakly arcuate, median surface more
markedly arcuate; palpomere 4 widest slightly past midlength. Mentum wider than long, surface shining, moderately and
sparsely punctulate. Submentum microreticulate. Genae shining; lateral area of each gena with well developed foveola;
posterior ridge absent. Postgena with microreticulation similar to that of submentum. Last five antennomeres pubescent.
Eyes slightly less than 0.25 interocular distance in width. Thorax: Pronotum length at midline 0.32 mm; maximum width
(at approximately midlength) 0.46 mm; sides margined, denticulate; sides relatively slightly produced at middle, slightly
arcuate and slightly convergent to anterior angle, very slightly sinuate and slightly convergent to posterior; anterior border
0.40 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50;
posterior border 0.44 mm wide, slightly arcuate to rear. Posterointernal foveolae very shallow. Posteroexternal foveola
absent. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended slightly less than 0.33
width of anterior region of pronotum. Transverse foveola slightly developed, punctures separated by thin walls. Disc
moderately shining, punctures fine, close and rather deeply impressed, separated by 0.50 puncture diameter near anterior
and posterior borders, by puncture diameter in middle; most punctures with seta extended above cuticle in dry specimens.

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180

Perkins

Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin, median
carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to
posterior; median carina extended to base of intercoxal process; intercoxal process relatively narrow, sides tapered; apex
rounded, width near apex 0.33 distance between internal and median carinae. Metasternum with plaques moderately
developed, straight, convergent very slightly from posterior to anterior; plaques 0.43 length of metasternum in midline;
width of each plaque subequal to width of intercoxal process at its midlength; plaques separated posteriorly by
approximately twice plaque width; plaques flat in cross section. Elytra: Length 0.88 mm. Maximum width (at
midlength) 0.56 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite
regular; most punctures round; intervals not elevated, width approximately equal to 0.50 puncture diameter, as are
interstices between adjacent punctures of a row; each puncture with seta. Explanate margin quite narrow, ending near
posterior 0.20, with extremely fine, well separated serrations along entire margin; serrations somewhat closer near
apices. Elytral apices, in dorsal aspect, almost truncate; viewed posteriorly, elytral margin elevated obliquely toward
suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly equilateral triangle, posterior
margin straight. Glabrous segments at apex well produced. Tergum 7 emarginate at apex; sternum with round
excavation on inner surface in midline. Legs: Protibiae rather markedly arcuate. Metatibia gradually enlarged to apex.
Genitalia: Aedeagus as illustrated (Fig. 64A)(37 examined).

Distribution. - (Figs. 92A,171B). Presently known from southeastern Brazil, Guyana, and
Venezuela.

Etymology. - Latin, hyalina (glassy, transparent). This name refers to the major process of
the aedeagus.

The trinidensis Complex

75. Hydraena browni new species
(Figs. 53A-B,92A,172A)

Type-locality. - San Fernando, Guarico, Venezuela.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. One male and one female paratype, same data as holotype, are also deposited in
USNM. Paul and Phyllis Spangler collected these specimens, February 12, 1969. One male
and two female paratypes (PDP) are from Para, Brazil.

Diagnosis. - The aedeagus must be used to reliably differentiate H. browni males from
other members of the marginicollis Subgroup of similar size, about 1.16 mm, and with plaques
elongate, separated by three times plaque width.

Description. — Form: Elongate. Size: Holotype 1.16 mm long, 0.50 mm wide. Color: Head with dorsal surface
black, with vague purple reflections; labrum black; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous
at anterior and posterior 0.25, black in middle 0.50; black blending into brown at sides. Elytra brown. Ventral surface dark
brown except legs, elytra epipleura and inflexed margin of pronotum brown. Head: Length 0.18 mm. Width 0.32 mm.
Frons finely and sparsely punctured, interstices twice puncture diameter; surface shining. Frontoclypeal suture straight.
Clypeus finely punctulate. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe
symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with following
lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.20/0.08/0.16; palpomere 2 bent outward at approximately
midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface slightly arcuate, median
surface more markedly arcuate. Mentum wider than long, surface shining, finely and sparsely punctulate. Submentum
sparsely, finely punctulate. Genae shining; lateral area of each gena with well developed foveola; posterior ridge absent.
Postgena with punctation slightly smaller than that of submentum. Last five antennomeres pubescent. Eyes slightly less
than 0.25 interocular distance in width. Thorax: Pronotum length at midline 0.30 mm; maximum width (at approximately
midlength) 0.42 mm; sides margined, denticulate; sides relatively slightly produced at middle, slightly arcuate and slightly
convergent to anterior angle, very slightly sinuate and slightly convergent to posterior; anterior border 0.36 mm wide,
straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border
0.38 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal foveola absent. Anteroexternal
foveolae well developed, each foveola somewhat cresent shaped, extended slightly less than 0.33 width of anterior region of

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Figs. 53A - D, Aedeagi of Hydraena species. (A) H. browni, holotype. (B) H. browni variant from Para, Brazil. (C) H.
trinidensis, holotype. (D) H. insular is, holotype.

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pronotum. Transverse foveola absent. Disc shining, punctures fine, separated by one-three times puncture diameter;
most punctures with distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate,
carina produced anteriorly as very short spine; coxae separated by thin, median carina, latter sinuate line in lateral
aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to
base of intercoxal process; intercoxal process relatively narrow, sides tapered, apex blunt, width at apex 0.50 distance
between internal and median carinae. Metasternum with plaques moderately developed, straight, convergent moderately
from posterior to anterior; plaques 0.57 length of metasternum in midline; width of each plaque subequal to width of
intercoxal process at its apex; plaques separated posteriorly by approximately three times plaque width; plaques flat in
cross section. Elytra: Length 0.76 mm. Maximum width (at midlength) 0.50 mm. surface shining, disc with 10 rows of
punctures between suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width
approximately equal to 0.50 puncture diameter, as are interstices between adjacent punctures of a row; each puncture
with a seta. Explanate margin quite narrow, ending near posterior 0.20, with extremely fine serrations in posterior 0.33.
Elytral apices, viewed from above, truncate; in posterior aspect, elytral margin rises obliquely toward suture, in form of
angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly equilateral triangle, posterior margin straight.
Glabrous segments at apex moderately produced, directed ventrad. Tergum 7 emarginate at apex; sternum with oval
excavation on inner surface at apex. Legs: Protibia excavate on inner surface at apex. Metafemur gradually enlarged
from base to apex. Genitalia: Aedeagus as illustrated (Figs. 53A-B)(16 examined).

Variation. - I have illustrated the aedeagus of a male from Para, Brazil (Fig. 53B), which
differs slightly from specimens from Venezuela. Externally, specimens from the two areas
compare very well.

Distribution. - (Figs. 92A,172A). Presently known from San Fernando, Venezuela, which is
in the Orinoco drainage system, and Para (Belem), Brazil, at the mouth of the Amazon River.

Etymology. - I am pleased to dedicate this species to Harley P. Brown in recognition of his
contributions to this study and to the study of aquatic Coleoptera in general.

76. Hydraena trinidensis new species
(Figs. 53C,172A)

Type-locality. - St. Augustine, Trinidad.

Type-specimens. - The holotype male is deposited in MCZ. The allotype and four female
paratypes from Mayaro, Trinidad, are also deposited in MCZ. These specimens were collected
by P. J. Darlington, April, 1929.

Diagnosis. - Difficult to differentiate from other members of the marginicollis Subgroup
which are about the same size (1.34 mm) and have the plaques moderately developed. The
aedeagus (Fig. 53C) must be studied to reliably assign males to this species.

Description. — Form: Elongate. Size: Holotype 1.34 mm long, 0.56 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior and posterior
0.25, dark brown in middle 0.50; sides slightly lighter than middle. Elytra brown. Ventral surface dark brown except legs,
elytral epipleura and inflexed margin of pronotum testaceous. Head: Length 0.18 mm; width 0.34 mm. Frons moderately
punctured, interstices one-two times puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus finely
microreticulate at sides, shining in midline. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate,
each lobe symmetrical arc; median emargination ending at approximately midlength of labrum. Maxillary palpus with
following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.24/0.08/0.16; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface slightly
arcuate, median surface rather markedly arcuate; palpomere 4 widest slightly past midlength. Mentum wider than long,
surface shining, finely and sparsely punctulate. Submentum finely punctulate, many punctures contiguous. Genae shining;
lateral area of each gena with well developed foveola; posterior ridge absent. Postgena microreticulate. Last five
antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width. Thorax: Pronotum length at midline
0.36 mm; maximum width (at approximately midlength) 0.44 mm; sides margined, denticulate; sides relatively slightly
produced at middle, slightly arcuate and slightly convergent to anterior angle, very slightly sinuate and slightly convergent
to posterior; anterior border 0.38 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately
arcuate to rear in middle 0.50; posterior border 0.40 mm wide, slightly arcuate to rear. Posterointernal foveolae absent.
Posteroexternal foveola absent. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended
slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not developed, punctures in this area
somewhat closer together than punctures on disc. Disc shining, punctures fine, separated by one-three times puncture

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diameter; most punctures with distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum
carinate, carina produced anteriorly as very short spine; coxae separated by thin, median carina, latter sinuate line in
lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior; median carina
extended to base of intercoxal process; intercoxal process relatively narrow, sides nearly parallel; apex blunt, width at
apex 0.50 distance between internal and median carinae. Metasternum with plaques moderately developed, triangular,
convergent moderately from posterior to anterior; plaques 0.43 length of metasternum in midline; greatest width of each
plaque subequal to width of intercoxal process at its apex; plaques separated posteriorly by approximately twice plaque
width; plaques on sides of median depression, sloped slightly toward midline. Elytra: Length 0.84 mm. Maximum width
(at midlength) 0.56 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite
regular; most punctures round; intervals not elevated, width approximately equal to puncture diameter, as are interstices
between adjacent punctures of a row; most punctures with a seta. Explanate margin quite narrow, ended near posterior
0.20, with extremely fine, well separated serrations in apical 0.33. Elytral apices, in dorsal aspect, almost truncate; in
posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen:
Intercoxal segment flat, longer than wide, posterior margin straight. Glabrous segments at apex moderately produced.
Tergum 7 emarginate at apex; sternum with oval excavation on inner surface in midline. Legs: Protibia slightly arcuate,
excavate on inner surface near apex. Genitalia: Aedeagus as illustrated (Fig. 53C)(1 examined).

Distribution. - (Fig. 172A). Presently known only from the island of Trinidad.

Etymology. - Latin adjective, trinidensis, in reference to the geographical distribution.

77. Hydraena insularis d’Orchymont
(Figs. 53D,172A)

Hydraena insularis d’Orchymont, 1945a:2 (holotype depository uncertain; type-locality: Guadeloupe).

Through the courtesy of the Institut Royal des Sciences Naturelles de Belgique, Brussels, I
have studied a male paratype of H. insularis. I am of the opinion that additional search may
reveal the holotype; therefore a lectotype is not designated herein.

Diagnosis. - Plaques of adults are well developed, triangular, separated at their bases by
about twice the greatest width of a plaque. Positive identifications of males must be based upon
the aedeagal form (Fig. 53D).

Description. — Form: Elongate. Size: Paratype 1.54 mm long, 0.68 mm wide. Color: Head with dorsal surface dark
brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior and posterior
0.25, dark brown in middle 0.50. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed
margin of pronotum brown. Head: Length 0.22 mm. Width 0.38 mm. Frons finely and sparsely punctured, interstices
one-three times puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus finely microreticulate at sides,
shining in midline. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical
arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively; 0.28/0.12/0.18; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly straight, median surface arcuate,
widest slightly past midlength. Mentum wider than long, surface moderately shining, punctures fine, separated by
puncture diameter. Submentum microreticulate. Genae shining; lateral area of each gena with well developed foveola;
posterior ridge absent. Postgena with punctation slightly larger than that of submentum. Last five
antennomeres pubescent. Eyes 0.25 interocular distance in width. Thorax: Pronotum length at midline 0.40 mm;
maximum width (at approximately midlength) 0.50 mm; sides margined, denticulate; sides relatively slightly produced at
middle, slightly arcuate and slightly convergent to anterior angle, slightly sinuate and slightly convergent to posterior;
anterior border 0.42 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in
middle 0.50; posterior border 0.46 mm wide, slightly arcuate to rear. Posterointernal and posteroexternal foveolae absent.
Transverse foveola not developed, punctures in this area closer together than punctures on disc. Disc shining, punctures
fine, separated by puncture diameter near anterior and posterior borders, and by two-three times puncture diameter in
middle; punctures without distinctive setae extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate,
carina produced anteriorly as short spine; coxae separated by thin, median carina, latter sinuate line in lateral aspect.
Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to base of
intercoxal process; intercoxal process relatively broad, sides nearly parallel, apex blunt, width at apex nearly 0.66 distance
separating internal and median carinae. Metasternum with plaques well developed, triangular, straight; plaques 0.50
length of metasternum in midline; greatest width of each plaque slightly greater than width of intercoxal process at its
midlength; plaques separated posteriorly by approximately twice plaque width; each plaque tapered from posterior to
anterior; plaques on sides of median depression, sloped slightly toward midline. Elytra: Length 1 .00 mm. Maximum width
(at midlength) 0.68 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite

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regular; most punctures round; intervals not elevated, width slightly greater than puncture diameter, as are interstices
between adjacent punctures of row; punctures without perceptible setae. Explanate margin quite narrow, ended near
posterior 0.20, with extremely fine, well separated serrations along entire margin; serrations somewhat closer near
apices. Elytral apices, in dorsal aspect, nearly truncate; in posterior aspect, elytral margin extended obliquely toward
suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly equilateral triangle, posterior
margin straight. Glabrous segments at apex moderately produced. Tergum 7 emarginate at apex; sternum with oval
excavation on inner surface to left of midline. Legs: Protibiae with a very small excavation on inner surface at apex.
Metatibiae gradually enlarging from base to apex. Genitalia: Aedeagus as illustrated (Fig. 53D)(2 examined).

Distribution. - (Fig. 172A). Presently known from Guadeloupe and Dominica (1 specimen
from the latter; see appendix).

Remarks. - The aedeagus I have illustrated from a paratype agrees well with the partial
illustration presented by d’Orchymont (1945). The aedeagus appears flattened because it had
been mounted on a microslide by a previous worker.

The marginicollis Complex

78. Hydraena marginicollis Kiesen wetter
(Figs. 54A-I,55A,56A,172B)

Hydraena marginicollis Kiesenwetter, 1849:177 (neotype deposited in USNM, herein designated; type-locality: three

miles S. Sopchoppy, Wakulla County, Florida). - d’Orchymont, 1923:36. - d’Orchymont 1945:1 Young, 1954:204.

Attempts to determine the location of the holotype of H. marginicollis have been

unsuccessful. I believe that this specimen has been destroyed. To insure taxonomic stability a
neotype is designated herein.

Diagnosis. - H. marginicollis is the only member of the marginicollis Group now known
from eastern North America (Fig. 56 A). H. marginicollis adults are distinguished from most
members of the marginicollis Subgroup by the moderate body size, about 1 .48 mm long, and
absence of metasternal plaques; the aedeagus must be used to differentiate males of this species
from others, such as H. pulsatrix, which also lack plaques.

Description. — Form: Elongate. Size: Neotype 1.48 mm long, 0.60 mm wide. Color: Head with dorsal surface dark
brown, nearly black; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior
and posterior 0.19, dark brown in middle 0.66; testaceous areas slightly larger at anterior and posterior angles; macula
slightly lighter at sides of pronotum. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed
margin of pronotum testaceous. Head: Length 0.20 mm. Width 0.32 mm. Frons finely and sparsely punctured, interstices
one-two times puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus finely punctulate. Labroclypeal
suture arcuate when viewed from above. Labrum bilobed, each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.24/0.12/0.16; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface straight, median surface arcuate; palpomere 4 widest near midlength. Mentum
width equal length, surface shining, finely and sparsely punctulate. Submentum finely punctulate, surface somewhat
irregular. Genae shining; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with
punctation much closer than those of mentum, contiguous. Last five antennomeres pubescent. Eyes 0.25 interocular
distance in width. Thorax: Pronotum length at midline 0.36 mm. maximum width (at approximately midlength) 0.46 mm;
sides margined, denticulate; sides relatively slightly produced at middle, slightly arcuate and slightly convergent to
anterior angle, very slightly sinuate and slightly convergent to posterior; anterior border 0.40 mm wide, straight and nearly
perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.42 mm wide, slightly
arcuate to rear. Posterointernal foveolae absent. Posteroexternal foveola absent. Anteroexternal foveolae well developed,
each foveola somewhat crescent shaped, extended slightly less than 0.25 width of anterior region of pronotum. Transverse
foveola absent. Disc shining, punctures fine, separated by puncture diameter near anterior and posterior borders, and by
twice puncture diameter in middle; punctures without distinctive setae extended above cuticle in dry specimens. Scintilla
absent. Prosternum carinate, carina produced anteriorly into very short spine; coxae separated by thin, median carina,
latter sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior;

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185

Figs. 54A - I, Hydraena marginicollis, <3. (A) dorsal habitus. (B) ventral habitus. (C) pronotum. (D) head, ventral aspect.
(E) elytra, posterior aspect. (F) metatibia. (G) prothoracic leg. (H) apex of protibia. (I) prosternum with leg removed.

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median carina extended to base of intercoxal process; intercoxal process relatively narrow, sides nearly parallel, apex
blunt, width at apex 0.50 distance between internal and median carinae. Metasternum with plaques absent. Elytra:
Length 0.89 mm. Maximum width (at midlength) 0.60 mm. Surface shining, disc with 10 rows of punctures between
suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width approximately equal
to puncture diameter, as are interstices between adjacent punctures of a row; most punctures with perceptible seta.
Explanate margin quite narrow, ended near posterior 0.20, with extremely fine, well separated serrations along entire
margin; serrations somewhat closer near apices. Elytral apices, in dorsal aspect, almost truncate; in posterior aspect,
elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment
flat, nearly equilateral triangle; anterior angle rounded; posterior margin straight. Glabrous segments at apex greatly
produced. Tergum 7 emarginate at apex; sternum with oval excavation on inner surface to left of midline. Legs:
Profemur with small tubercle on inner surface near midlength. Protibia excavate on inner surface near apex. Metatibia
nearly parallel sided in apical 0.66. Genitalia: Aedeagus as illustrated (Fig. 55A)(60 examined).

Natural History. - H. marginicollis is primarily a lowland pond species (Fig. 194C). It is
quite common in Florida, being collected in such areas as, “emergent vegetation at lake shore”,
“small pools adjacent to reservoir”, “litter under water hyacinth at creek”, and “debris, lake
shore”. There is also some indication that it may be slightly salt tolerant. I have examined 177
specimens (see appendix).

Distribution. - (Figs. 56A,172B). Eastern North America, primarily coastal, from New
Jersey south to Louisiana.

79. Hydraena turrialba new species
(Figs. 55B,172B)

Type-locality. - Turrialba, Costa Rica.

Type-specimens. - The holotype male, allotype and one female paratype with same locality
data are deposited in USNM. Paul J. Spangler collected these specimens, July 15, 1965.

Diagnosis. - Aedeagal form is the only reliable means of distinguishing males of H.
turrialba from those of other species of the marginicollis Subgroup which have small, oval
plaques and are of approximately the same body size (1.40 x 0.64 mm).

Description. — Form: Elongate. Size: Holotype 1.40 mm long, 0.64 mm wide. Color: Head with dorsal surface
black except for brown area near eyes; labrum dark brown; maxillary palpi and antennae testaceous. Pronotum testaceous
at anterior and posterior 0.25, black in middle 0.50; black blending into dark brown at sides. Elytra brown. Ventral surface
dark brown except legs, elytral epipleura and indexed margin of pronotum brown. Head: Length 0.20 mm. Width
0.36 mm. Frons finely punctured, interstices one-three times puncture diameter; surface shining. Frontoclypeal suture
straight. Clypeus finely microreticulate at sides, shining in middle. Labroclypeal suture arcuate in dorsal aspect. Labrum
bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of labrum.
Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.24/0.10/0.16; palpomere 2 bent
outward at approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral
surface slightly arcuate, median surface more markedly arcuate; palpomere 4 widest slightly past midlength. Mentum
wider than long, surface shining, finely and sparsely punctulate. Submentum finely and sparsely punctulate. Genae
moderately shining; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with punctation
slightly smaller than that of submentum. Last five antennomeres pubescent. Eyes slightly less than 0.25 interocular
distance in width. Thorax: Pronotum length at midline 0.38 mm; maximum width (at approximately midlength) 0.48 mm;
sides margined, denticulate; sides relatively weakly produced at middle, slightly arcuate and slightly convergent to anterior
angle, very slightly sinuate and slightly convergent to posterior; anterior border 0.40 mm wide, straight and nearly
perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.44 mm wide, slightly
arcuate to rear. Posterointernal foveolae absent; punctures in foveola similar to those on disc. Posteroexternal foveola
absent. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended slightly less than 0.33
width of anterior region of pronotum. Transverse foveola absent. Disc shining, punctures fine, separated by puncture
diameter near anterior and posterior borders, and by two-three times puncture diameter in middle; most punctures with
distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly
as very short spine; coxae separated by thin, median carina, latter sinuate line in lateral aspect. Mesosternum with internal
and external carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal
process relatively narrow, sides tapered, apex blunt, width at apex 0.33 distance between internal and median carinae.
Metasternum with plaques very slightly developed, small ovals at posterior 0.20; width of each plaque 0.50 width of

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187

intercoxal process at its apex; plaques separated posteriorly by approximately four times plaque width; plaques flat in
cross section. Elytra: Length 0.92 mm. Maximum width (at midlength) 0.64 mm. Surface shining, disc with 10 rows of
punctures between suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width
approximately equal to puncture diameter, as are interstices between adjacent punctures of row; each puncture with
seta. Explanate margin quite narrow, ended near posterior 0.20, with fine serrations near anterior angles and in
posterior 0.33; serrations somewhat closer near apices. Elytral apices, in dorsal aspect, truncate; in posterior aspect,
elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment
flat, wider than long, posterior margin straight. Glabrous segments at apex clearly produced, arched ventrad. Tergum 7
emarginate at apex; sternum with small, oval excavation on inner surface distinctly to left of midline. Legs: Profemur
with tubercle on inner surface near midlength. Protibia slightly arcuate, excavate at apex. Metatibia nearly
parallel-sided in apical 0.80. Genitalia: Aedeagus as illustrated (Fig. 55B)(1 examined).

Distribution. - (Fig. 172B). Presently known only from the type-locality, Turrialba, Costa
Rica.

Etymology. - Latin in form, noun in apposition, turrialba in reference to the type-locality.

80. Hydraena pulsatrix new species
(Figs. 55C,56A,172B)

Type-locality. - Ciudad Mante, Tamaulipas, Mexico.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. Paul J. Spangler collected these specimens, August 22, 1964. Paratypes (32) are listed
in the appendix.

Diagnosis. - The aedeagus must be used to distinguish males of this species from others in
the marginicollis Subgroup which are in its size range (about 1.56 mm long) and lack
metasternal plaques. It is very closely related to H. longicollis.

Description. — Form: Elongate. Size: Holotype 1.56 mm long, 0.56 mm wide. Color: Head with dorsal surface dark
brown, nearly black; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior
and posterior 0.22, dark brown in middle 0.56; testaceous areas slightly larger at anterior and posterior angles; macula
slightly lighter at sides of pronotum. Elytra brown. Ventral surface dark brown except legs, elytral epipleura, apex of
abdomen, and inflexed margin of pronotum testaceous. Head: Length 0.20 mm. Width 0.36 mm. Frons finely and sparsely
punctured, interstices one-two puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus finely
punctulate. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc;
median emargination ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.24/0.10/0.16; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface very slightly arcuate, median surface more
markedly arcuate; palpomere 4 widest near midlength. Mentum width equal length, surface moderately shining, finely and
sparsely punctulate. Submentum microreticulate. Genae shining; lateral area of each gena with well developed foveola;
posterior ridge absent. Postgena with punctation similar to that of submentum. Last five antennomeres pubescent. Eyes
0.25 interocular distance in width. Thorax: Pronotum length at midline 0.36 mm. maximum width (at approximately
midlength) 0.46 mm; sides margined, denticulate; sides relatively slightly produced at middle, slightly arcuate and slightly
convergent to anterior angle, very slightly sinuate and slightly convergent to posterior; anterior border 0.40 mm wide,
straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border
0.44 mm wide, slightly arcuate to rear. Posterointernal, posteroexternal and transverse foveolae absent. Anteroexternal
foveolae well developed, each foveola somewhat crescent shaped, extended slightly less than 0.33 width of anterior region
of pronotum. Disc shining, punctures fine, separated by one-two times puncture diameter; each puncture with distinctive
seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very
short spine; coxae separated by thin, median carina, latter sinuate line in lateral aspect. Mesosternum with internal and
external carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal
process relatively narrow, sides nearly parallel, apex blunt, width at apex 0.50 distance between internal and median
carinae. Metasternum with plaques absent. Elytra: Length 0.96 mm. Maximum width (at midlength) 0.56 mm. Surface
shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most punctures round;
intervals not elevated, width approximately equal to 0.50 puncture diameter, as are interstices between adjacent punctures
of a row; each puncture with seta. Explanate margin quite narrow, ended near posterior 0.20, with fine serrations near
anterior angles and posterior 0.33. Elytral apices, in dorsal aspect, almost truncate; viewed posteriorly, elytral margin
extended obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than
long, posterior margin straight. Glabrous segments at apex greatly produced. Tergum 7 emarginate at apex; sternum with

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Figs. 55A - D, Aedeagi of Hydraena species. (A) H. marginicollis , neotype (inset: apex rotated slightly). (B) H. turrialba ,
holotype. (C) H. pulsatrix, holotype (inset: apex rotated slightly). (D) H. longicollis, lectotype (inset: apex rotated
slightly).

oval excavation on inner surface to left of midline. Legs: Profemur with small tubercle on inner surface near midlength.
Protibia excavate on inner surface at apex. Metatibia nearly parallel sided in apical 0.66. Genitalia: Aedeagus as
illustrated (Fig. 55C)(19 examined).

Natural History. - Locality data include the habitat notations, “mucky dead grass mat,
margin of small lake”, “streamside litter under cypress”, and “floor, willow swamp”.

Distribution. - (Figs. 56A,172B). Texas to southern Mexico.

Etymology. - Latin, pulsator (striker, beater). I have observed that H. marginicollis males,
during copulation, pulsate the aedeagus forward and backward at a frequency of approximately
two pulsations per second. In light of the structural similarity of the aedeagi of H. pulsatrix

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189

Figs. 56A - B, Geographical distributions of Hydraena species. (A) H. marginicollis • , H. pulsatrix ★ and H.
longicollis A • (B) H. spangleri.

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and H. marginicollis, I predict that this behavior will also be found in the former species.

Remarks. - The differences in the aedeagi of H. pulsatrix and H. longicollis are slight but
apparently constant.

8 1 . Hydraena longicollis Sharp

(Figs. 55D,56A,172B)

Hydraena longicollis Sharp, 1882:93 (lectotype male deposited in BMNH, here designated; type-locality: San Geronimo,

Baja Verapaz, Guatemala).

Diagnosis. - The aedeagus must be used to differentiate males of H. longicollis from those
of other species in the marginicollis Subgroup which are of approximately the same size, about
1 .44 mm long, and have the plaques reduced to small ovals.

Description. — Form: Elongate. Size: Lectotype 1.44 mm long, 0.53 mm wide. Color: Head with dorsal surface and
labrum black; maxillary palpi and antennae brown. Pronotum black except anterior angles and posterior border brown.
Elytra brown. Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum brown. Head:
Length 0.18 mm. Width 0.34 mm. Frons moderately punctured, interstices one-four times puncture diameter; surface
shining. Frontoclypeal suture straight. Clypeus finely punctulate at sides, shining in middle. Labroclypeal suture arcuate
when viewed from above. Labrum bilobed; surface punctulate; each lobe symmetrical arc; median emargination ended
slightly before midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively;
0.26/0.12/0.16; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface nearly straight, median surface arcuate; palpomere 4 widest slightly past
midlength. Mentum wider than long, surface moderately shining, finely punctulate. Submentum punctation coarser and
closer than mentum. Genae shining with irregular sculpture in form of transverse lines; lateral area of each gena with well
developed foveola; posterior ridge absent. Postgena with close and fine punctation. Last five antennomeres pubescent. Eyes
0.25 interocular distance in width. Thorax: Pronotum length at midline 0.34 mm; maximum width (at approximately
midlength) 0.44 mm; sides margined, denticulate; sides relatively slightly produced at middle, slightly arcuate and slightly
convergent to anterior angle, very slightly sinuate and slightly convergent to posterior; anterior border 0.38 mm wide,
straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border
0.41 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal foveola absent. Anteroexternal
foveolae well developed, each foveola somewhat crescent shaped, extended slightly less than 0.33 width of anterior region
of pronotum. Transverse foveola not developed, punctures in this area somewhat closer together than punctures on disc.
Disc shining, punctures fine, separated by two-four times puncture diameter; most punctures without distinctive seta
extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short
spine; coxae separated by thin, median carina, latter sinuate line in lateral aspect. Mesosternum with internal and external
carinae diverging from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process
relatively narrow, sides tapered; apex blunt, width at apex 0.50 distance between internal and median carinae.
Metasternum with plaques moderately developed, straight, parallel; plaques 0.50 length of metasternum in midline;
greatest width of each plaque subequal to width of intercoxal process at its apex; plaques separated posterior by
approximately three times plaque width; plaques flat in cross section. Elytra: Length 1.00 mm. Maximum width (at
midlength) 0.53 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite
regular; most punctures round; intervals not elevated, width approximately equal to puncture diameter, as are interstices
between adjacent punctures of row; most punctures with seta. Explanate margin quite narrow, ended near posterior 0.20,
with extremely fine, well separated serrations along anterior 0.66, serrations quite large and distinct in posterior 0.33,
serrations somewhat closer near apices. Elytral apices, in dorsal aspect, truncate; in posterior aspect, elytral margin
elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, nearly
equilateral triangle; posterior margin straight. Glabrous segments at apex moderately produced. Tergum 7 emarginate at
apex; sternum with oval excavation on inner surface to left of midline. Legs: Profemur with tubercle on inner surface near
midlength. Protibia excavate on inner surface at apex. Metatibia gradually enlarging to apex. Genitalia: Aedeagus as
illustrated (Fig. 55D)(8 examined).

Distribution. - (Figs. 56A,172B). Presently known from southern Mexico, Guatemala, and
Nicaragua. I have examined 15 specimens (see appendix).

82. Hydraena peru new species

(Figs. 58A,172B)

Type-locality. - Tingo Maria, Huanuco, Peru.

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191

Type-specimens. - The holotype male, allotype and one female paratype with same data are
deposited in USNM. Paul and Phyllis Spangler collected these specimens, April 19-24, 1969.

Diagnosis. - Moderately small body size plus geographical distribution (Peru) is of some aid
in assigning specimens to this species. Positive identifications should be based upon the
aedeagus (Fig. 58A).

Description. — Form: Elongate. Size: Holotype 1.32 mm long, 0.60 mm wide. Color: Head with dorsal surface
black; labrum black; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior and posterior 0.25,
very dark brown in middle 0.50; sides much lighter brown than disc. Elytra brown. Ventral surface dark brown except legs,
elytral epipleura and inflexed margin of pronotum brown. Head: Length 0.18 mm. Width 0.34 mm. Frons finely and
sparsely punctured, interstices one-three times puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus
finely microreticulate at sides, shining in midline. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed,
microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary
palpus with follwing lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.22/0.08/0.16; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface slightly
arcuate, median surface more markedly arcuate; palpomere 4 widest slightly past midlength. Mentum wider than long,
surface shining, finely and sparsely punctulate. Submentum finely and sparsely punctulate. Genae shining; lateral area of
each gena with well developed foveola; posterior ridge absent. Postgena with punctation slightly smaller than that of
submentum. Last five antennomeres pubescent. Eyes slightly less than 0.25 intercular distance in width. Thorax:
Pronotum length at midline 0.34 mm. maximum width (at approximately midlength) 0.44 mm; sides margined,
denticulate; sides relatively weakly produced at middle, slightly arcuate and slightly convergent to anterior angle, very
slightly sinuate and slightly convergent to posterior; anterior border 0.36 mm wide, straight and nearly perpendicular to
midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.42 mm wide, slightly arcuate to rear.
Posterointernal foveolae absent. Posteroexternal foveola absent. Anteroexternal foveolae well developed, each foveola
somewhat crescent shaped, extended slightly less than 0.33 width of anterior region of pronotum. Transverse foveola
absent. Disc shining, punctures fine; separated by one-three times puncture diameter; most punctures with seta extended
above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly into very short spine;
coxae separated by thin, median carina, latter sinuate line in lateral aspect. Mesosternum with internal and external
carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process
relatively broad, sides tapered, apex blunt, width at apex 0.66 distance between internal and median carinae. Metasternum
with plaques slightly developed, of small ovals at posterior 0.20; width of each plaque 0.50 width of intercoxal process at its
midlength; plaques separated posteriorly by approximately three times plaque width; plaques flat in cross section. Elytra:
Length 0.84 mm. Maximum width (at midlength) 0.60 mm. Surface shining, disc with 10 rows of punctures between
suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width approximately equal to
0.50 puncture diameter, as are interstices between adjacent punctures of row; each puncture with seta. Explanate margin
quite narrow, ended near posterior 0.20, with extremely fine, well separated serrations along entire margin; serrations
closer near apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely
toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin
straight. Glabrous segments at apex well produced, directed ventrad. Tergum 7 emarginate at apex; sternum with oval
excavation on inner surface in midline. Legs: Profemur with small tubercle on inner surface near midlength. Protibia
excavate on inner surface at apex. Metatibia nearly parallel sided in apical 0.80. Genitalia: Aedeagus as illustrated
(Fig. 58A)(1 examined).

Distribution. - (Fig. 172B). Presently known only from the type-locality, Tingo Maria,
Peru.

Etymology. - Noun in apposition, peru, in reference to the geographical distribution.

The anisonycha Complex

83. Hydraena anisonycha new species
(Figs. 2C,E,50B,57A-F,58B,153H)

Type-locality. - Eleven km. N. Bogota, Cundinamarca, Colombia.

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Figs. 57A - F, Hydraena anisonycha, 3. (A) head, ventral aspect. (B) metasternum. (C) metathoracic leg. (D) mesotarsal
claw. (E-F) Metatibia.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. Paul and Phyllis Spangler collected these specimens, March 1-8, 1969. Paratypes
(1714), all also collected by the Spanglers, are listed in the appendix.

Diagnosis. - Adults of this very unusual species are characterized by the non-serial elytral
punctation, plaques (Fig. 57B), which are carinate at the lateral margins, and large size, about
2.00 mm long. Males have the following autapomorphous features: 1) Shape of the hind tibiae
(Figs. 57C,E-F); 2) very asymmetrical mesotarsal claws (Fig. 57D); 3) a median tubercle on
abdominal sternum 2; and 4) aedeagal form (Fig. 58B).

Description. — Form: Elongate-oval. Size: Holotype 1.98 mm long, 0.84 mm wide. Color: Head with dorsal surface
dark brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior and
posterior 0.20, dark brown in middle 0.60. Elytra brown. Ventral surface dark brown except legs, elytral epipleura and
inflexed margin of pronotum brown. Head: Length 0.24 mm. Width 0.44 mm. Frons rather coarsely punctured, most
interstices less than puncture diameter; surface shining. Frontoclypeal suture bisinuate. Clypeus microreticulate at sides.

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193

shining in midline. Labroclypeal suture straight across middle in dorsal aspect. Labrum bilobed, microreticulate, each
lobe symmetrical arc; median emargination ended at approximately midlength of labrum Maxillary palpus with
following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.34/0.16/0.24; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly
straight in basal 0.33, arcuate in apical 0.66, median surface arcuate; palpomere 4 widest near apical 0.33. Mentum
wider than long, surface moderately shining, finely microreticulate. Submentum microreticulate. Genae shining; lateral
area of each gena with a well developed foveola; posterior ridge absent. Postgena with microreticulation similar to that
of submentum. Last five antennomeres pubescent. Eyes 0.20 interocular distance in width. Thorax: Pronotum length at
midline 0.48 mm; maximum width (at approximately midlength) 0.64 mm; sides margined, denticulate; sides
moderately produced at middle, slightly arcuate and convergent to anterior angle, very slightly sinuate and slightly
convergent to posterior; anterior border 0.48 mm wide, straight and nearly perpendicular to midline in lateral 0.25,
moderately arcuate to rear in middle 0.50; posterior border 0.60 mm wide, slightly arcuate to rear. Posterointernal
foveolae absent. Posteroexternal foveola extremely weakly developed. Interfoveolar depression weakly developed.
Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended slightly less than 0.33 width
of anterior region of pronotum. Transverse foveola not developed, punctures in this area somewhat closer together than
punctures on disc. Disc shining, punctures moderately sized, generally separated by less than puncture diameter; each
puncture with distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina
produced anteriorly as very short spine; coxae separated by thin, median carina, latter sinuate line in lateral aspect.
Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to base of
intercoxal process; intercoxal process relatively narrow, slightly wider at apex than at midlength, apex blunt, width at
apex 0.50 distance between internal and median carinae. Metasternum with plaques well developed, arcuate; plaques
0.50 length of metasternum in midline; width of each plaque subequal to width of intercoxal process at its midlength;
plaques separated posteriorly by approximately three times plaque width; each plaque with lateral margin carinate.
Elytra: Length 1.36 mm. Maximum width (at midlength) 0.84 mm. Surface shining, disc with first two rows (from
suture) somewhat distinct, other punctures randomly arranged; punctures with seta. Explanate margin moderately
developed, ended near posterior 0.50, without distinctive serrations. Elytral apices, in dorsal aspect, gradually rounded;
in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen:
Intercoxal segment flat, nearly equilateral triangle; posterior margin straight. Second complete sternum with tubercle in
midline. Glabrous segments at apex well produced. Tergum 7 asymmetrical, emarginate and markedly concave at apex.
Legs: Profemur with small carina on inner surface at base. Protibia arcuate, expanded in apical 0.50. Mesotibia slightly
arcuate. Mesotarsal claws markedly asymmetrical; apical article of mesotarsus with prominent setae on inner surface.
Metafemur broad, lateral surface markedly arcuate, medial surface sinuate. Metatibia markedly expanded on inner
surface near apical 0.33. Genitalia: Aedeagus as illustrated (Fig. 58B)(60 examined).

Natural History . - Most of the known specimens were collected at the margins of ponds.
Distribution. - (Fig. 50B). Presently known only from the vicinity of Bogota, Colombia.
Etymology. - Greek, anios (unequal) plus onycha (claw). This name refers to the markedly
asymmetrical claws of the male mesotarsi.

The colymba Complex

84. Hydraena colymba new species
(Figs. 59,60A,173)

Type-locality. - Six miles N. Jalapa, Jalapa, Guatemala.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. My wife Maureen and I collected these specimens, June 15, 1974. Paratypes (55)
are listed in the appendix.

Diagnosis. - Moderately large size (about 1.60 mm long) and elongate plaques which are
separated by three-four times the width of a plaque are of aid in distinguishing specimens of H.
colymba from others in the marginicollis Subgroup . The very distinctive aedeagus (Fig. 60A)
should be used for totally reliable identifications.

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Figs. 58A - B, Aedeagi of Hydraena holotypes. (A) H. peru. (B) H. anisonycha.

Fig. 59. Geographical distributions of Hydraena guadelupensis # , H. oblio ★ , H. colymba A , H. particeps A and H.
sabella ■ .

Western Hemisphere Hydraenidae

195

Description. — Form: Elongate. Size: Holotype 1 .60 mm long, 0.68 mm wide. Color: Head with dorsal surface
black; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at anterior and posterior
0.14, dark brown in middle 0.71; testaceous margin at sides as wide as anterior testaceous border. Elytra brown. Ventral
surface dark brown except legs, elytral epipleura and inflexed margin of pronotum brown. Head: Length 0.22 mm. Width
0.40 mm. Frons moderately punctured, interstices equal to or slightly greater than puncture diameter; surface shining.
Frontoclypeal suture straight. Clypeus finely punctulate at sides, shining in midline. Labroclypeal suture arcuate in dorsal
aspect. Labrum bilobed; surface punctulate, each lobe symmetrical arc; median emargination ended at approximately
midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.28/0.12/0.18; palpomere 3 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface nearly straight, median surface arcuate; palpomere 4 widest slightly past
midlength. Mentum wider than long, surface shining, evenly and moderately finely punctulate. Submentum punctures
unevenly distributed, forming aggregates. Genae shining; lateral area of each gena with well developed foveola; posterior
ridge absent. Postgena with punctation smaller than that of submentum, punctures contiguous. Last five
antennomeres pubescent. Eyes 0.25 interocular distance in width. Thorax: Pronotum length at midline 0.44 mm;
maximum width (at approximately midlength) 0.54 mm; sides margined, denticulate; sides relatively slightly produced at
middle, slightly arcuate and slightly convergent to anterior angle, very slightly sinuate and slightly convergent to posterior;
anterior border 0.44 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in
middle 0.50; posterior border 0.50 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal
foveola absent. Interfoveolar depression very slightly developed. Anteroexternal foveolae well developed, each foveola
somewhat crescent shaped, extended slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not
developed, punctures in this area somewhat closer together than punctures on disc. Disc shining, punctures fine, separated
by one-three times puncture diameter; most punctures with distinctive seta extended above cuticle in dry specimens.
Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin, median
carina; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to
posterior; median carina extended to base of intercoxal process; intercoxal process relatively broad, sides nearly parallel;
apex blunt, width at apex 0.66 distance between internal and median carinae. Metasternum with plaques moderately
developed, straight, parallel; plaques 0.50 length of metasternum in midline, but anterior 0.50 of each plaque somewhat
diffuse with pubescence; width of each plaque slightly less than width of intercoxal process at its apex; plaques separated
posteriorly by approximately twice plaque width; plaques on sides of median depression, sloped slightly toward midline.
Elytra: Length 1.00 mm. Maximum width (at midlength) 0.68 mm. Surface shining, disc with 10 rows of punctures
between suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width approximately
equal to puncture diameter, as are interstices between adjacent punctures of a row; most punctures with seta. Explanate
margin quite narrow, ended near posterior 0.10, with extremely fine serrations in apical 0.33. Elytral apices, in dorsal
aspect, truncate; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite
elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous segments at apex
moderately produced. Tergum 7 emarginate at apex; sternum with circular excavation on inner surface. Legs: Protibia
arcuate, gradually enlarged from base to apex. Metatibia gradually enlarged from base to apex. Genitalia: Aedeagus as
illustrated (Fig. 60A)(26 examined).

Natural History. - The stream at the type-locality is rather slow, in an open, slightly arid
area (Fig. 195A). Limnebius sinuatus adults were also collected at the margin of this stream.
The only other habitat information available is the label notation, “in algae, rain pond”.

Distribution. - (Figs. 59,173). From the mountains of Chiapas, Mexico south through
Guatemala and Honduras to Costa Rica.

Etymology. - Latin, colymba (a diving bird). This name refers to the aedeagus, which has
the apex shaped like a bird’s head; and to the aquatic habits.

85. Hydraena nevermanni new species
(Figs. 60B,173)

Type-locality. - Hamburgfarm, Reventazon, Costa Rica.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. F. Nevermann collected these specimens, February 23, 1933. Paratypes (57) are
listed in the appendix.

Diagnosis. - The small plaques of adults of this species are widely separated, the distance
between them being about five-six times the width of a plaque. The pronotum is relatively

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finely and sparsely punctate for a species of the marginicollis Subgroup , and the body size is
moderate, about 1.34 mm long. The aedeagus is very distinctive, and should be used for totally
reliable specimen assignment.

Description. — Form: Elongate. Size: Holotype 1 .34 mm long, 0.56 mm wide. Color: Head with dorsal surface dark
brown, nearly black; labrum dark brown; maxillary palpi and antennae testaceous. Pronotum testaceous at anterior and
posterior 0.25, dark brown in middle 0.50; sides distinctly lighter than disc. Elytra brown. Ventral surface dark brown
except legs, elytral epipleura and inflexed margin of pronotum brown. Head: Length 0.20 mm. Width 0.36 mm. Frons
moderately finely punctured, interstices one-three times puncture diameter; surface shining. Frontoclypeal suture straight.
Clypeus finely punctulate at sides, shining in midline. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed;
surface punctulate; each lobe symmetrical arc; median emargination at approximately midlength of labrum. Maxillary
palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.24/0.12/0.16; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface slightly
arcuate, median surface more markedly arcuate; palpomere 4 widest slightly past midlength. Mentum wider than long,
surface shining, finely and sparsely punctulate. Submentum punctures uneven, in form of aggregates. Genae shining;
lateral area of each gena with well developed foveola; posterior ridge absent. Postgena with punctures fine and contiguous.
Last five antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width. Thorax: Pronotum length at
midline 0.36 mm; maximum width (at approximately midlength) 0.46 mm; sides margined, denticulate; sides relatively
weakly produced at middle, slightly arcuate and slightly convergent to anterior angle, very slightly sinuate and slightly
convergent to posterior; anterior border 0.40 mm wide, straight and nearly perpendicular to midline in lateral 0.25,
moderately arcuate to rear in middle 0.50; posterior border 0.42 mm wide, slightly arcuate to rear. Posterointernal foveolae
absent. Posteroexternal foveola absent. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped,
extended slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not developed, punctures in this
area closer together than punctures on disc. Disc shining, punctures fine, separated by two-three times puncture diameter;
most punctures with seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced
anteriorly as very short spine; coxae separated by thin, median carina, latter sinuate line in lateral aspect. Mesosternum
with internal and external carinae divergent from anterior to posterior; median carina extended to base of intercoxal
process; intercoxal process relatively narrow, sides nearly parallel, apex blunt, width at apex slightly less than 0.50 distance
between internal and median carinae. Metasternum with plaques very slightly developed, of small ovals at posterior 0.20;
width of each plaque 0.33 width of intercoxal process at its apex; plaques separated posteriorly by approximately six times
plaque width; plaques flat in cross section. Elytra: Length 0.84 mm. Maximum width (at midlength) 0.56 mm. Surface
shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most punctures round;
intervals not elevated, width approximately equal to 0.50 puncture diameter, as are interstices between adjacent punctures
of a row; most punctures with a seta. Explanate margin quite narrow, ended near posterior 0.20, without perceptible
serrations. Elytral apices, in dorsal aspect, truncate; in posterior aspect, elytral margin elevated obliquely toward suture, in
form of angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight.
Glabrous segments at apex moderately produced. Tergum 7 emarginate at apex, sternum with round excavation on inner
surface in midline. Legs: Protibia arcuate; inner surface expanded in apical 0.33. Metatibia gradually enlarged from base
to apex. Genitalia: Aedeagus as illustrated (Fig. 60B)(26 examined).

Distribution. - (Fig. 173). Presently known only from the type-locality in Costa Rica.

Etymology. - Dedicated to the collector.

86 Hydraena malkini new species
(Figs. 60C,173)

Type-locality. - Tres Rios, Costa Rica.

Type-specimens. - The holotype male is deposited in CAS. One male paratype (USNM) is
labelled: Palmares, tiny pool in hard shale, high on riverbank, 7-XII-1955. Both of these
specimens were collected by Borys Malkin.

Diagnosis. - Adults are moderately large, about 1 .44 mm long, with plaques narrow, about
three times as long as wide; a distance equal to about two-three times the width of a plaque
separates them. The aedeagus must be employed to discriminate males of H. malkini from
males of other members of the marginicollis Subgroup of similar body size and plaque
configuration.

Description. — Form: Elongate. Size: Holotype 1.44 mm long, 0.60 mm wide. Color: Head with dorsal surface
black, faint purple reflections apparent; labrum black; maxillary palpi and antennae testaceous. Pronotum testaceous at

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197

Figs. 60A - D, Aedeagi of Hydraena holotypes. (A) H. colymba. (B) H. nevermanni. (C) H. malkini. (D) H. pontequula.

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anterior and posterior 0.25, dark brown in middle 0.50; sides lighter than disc. Elytra brown. Ventral surface dark
brown except legs, elytral epipleura and indexed margin of pronotum testaceous. Head: Length 0.20 mm. Width
0.34 mm. Frons finely and sparsely punctured, interstices two-three times puncture diameter; surface shining.
Frontoclypeal suture straight. Clypeus finely microreticulate at sides, shining in midline. Labroclypeal suture arcuate in
dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4,
respectively: 0.24/0.12/0.14; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not
especially expanded; palpomere 4 with lateral surface nearly straight, median surface arcuate; palpomere 4 widest
slightly past midlength. Mentum wider than long, surface shining, finely and extremely sparsely punctulate.
Submentum shining, nearly impunctate. Genae moderately elevated, shining; lateral area of each gena with well
developed foveola; posterior ridge absent. Postgena punctures fine and contiguous. Last five antennomeres pubescent.
Eyes slightly less than 0.20 interocular distance in width. Thorax: Pronotum length at midline 0.36 mm; maximum
width (at approximately midlength) 0.46 mm; sides margined, denticulate; sides relatively slightly produced at middle,
slightly arcuate and slightly convergent to anterior angle, slightly sinuate and convergent to posterior; anterior border
0.40 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50;
posterior border 0.42 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal foveola absent.
Interfoveolar depression very slightly developed. Anteroexternal foveolae well developed, each foveola somewhat crescent
shaped, extended slightly less than 0.33 width of anterior region of pronotum. Transverse foveola not developed,
punctures in this area somewhat closer together than punctures on disc. Disc extremely shiny, punctures fine and sparse,
separated by two-four times puncture diameter; punctures without distinctive setae extended above cuticle in dry
specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by
thin, median carina, latter sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from
anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively broad, sides
parallel; apex blunt, width at apex 0.66 distance between internal and median carinae. Metasternum with plaques
moderately developed, straight, parallel; plaques 0.40 length of metasternum in midline; width of each plaque subequal
to width of intercoxal process at its apex; plaques separated posteriorly by approximately twice plaque width; plaques on
sides of median depression, sloped toward midline. Elytra: Length 0.88 mm. Maximum width (at midlength) 0.60 mm.
Surface shining, disc with 10 rows of punctures between suture and humeral callus, rows quite regular; most punctures
round; intervals not elevated, width approximately equal to twice puncture diameter, as are interstices between adjacent
punctures of row; most punctures with seta. Explanate margin quite narrow, ended near posterior 0.20, with extremely
fine, well separated serrations along entire margin; serrations slightly closer near apices. Elytral apices, in dorsal aspect,
gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite
elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous segments at apex
moderately produced. Tergum 7 emarginate at apex; sternum with oval excavation on inner surface in midline. Legs:
Protibia expanded on inner surface in apical 0.33. Meso- and metatibia slightly arcuate in apical 0.33. Genitalia:
Aedeagus as illustrated (Fig. 60C)(2 examined).

Variation. - The paratype from Palmares has the pronotal and mental punctation decidedly
more dense than that of the holotype.

Distribution. - (Fig. 173). Presently known only from Costa Rica.

Etymology. - I am pleased to dedicate this species to its collector, Borys Malkin, in
recognition of the many specimens made available to this study due to his excellent field work.

87. Hydraena pontequula new species
(Figs. 60D,173)

Type-locality. - Albrook Forest Site, Canal Zone, Panama.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. These specimens were collected by Hutton, January 19-20, 1968. Paratypes (165)
are listed in the appendix.

Diagnosis. - Small body size, about 1.14 mm long, and plaques elongate and separated from
one another by about four times the width of a plaque, help to distinguish specimens of H.
pontequula. The very distinctive aedeagus (Fig. 60D) must be used to reliably distinguish
between males of this species and others in the marginicollis Subgroup of similar body size and
plaque configuration.

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199

Description. — Form: Elongate. Size: Holotype 1.14 mm long, 0.48 mm wide. Color: Head with dorsal surface
brown; labrum dark brown; maxillary palpi and antennae testaceous. Pronotum testaceous except for transverse,
rectangular, brown (lighter than head) macula on disc. Elytra brown. Ventral surface dark brown except legs, elytral
epipleura and inflexed margin of pronotum testaceous. Head: Length 0.16 mm. Width 0.32 mm. Frons moderately
punctate, interstices equal to or slightly greater than puncture diameter; surface shining. Frontoclypeal suture arcuate to
rear. Clypeus finely microreticulate at sides, shining in midline. Labroclypeal suture arcuate in dorsal aspect. Labrum
bilobed, microreticulate, each lobe symmetrical arc; median emargination ended slightly above midlength of labrum.
Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.20/0.08/0.14; palpomere 2 bent
outward at approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral
surface nearly straight, median surface arcuate; palpomere 4 widest slightly past midlength. Mentum wider than long,
surface shining, finely and sparsely punctulate. Submentum finely and sparsely punctulate. Genae shining; lateral area of
each gena with well developed foveola; posterior ridge absent. Postgena microreticulate. Last five antennomeres pubescent.
Eyes slightly less than 0.20 interocular distance in width. Thorax: Pronotum length at midline 0.28 mm; maximum width
(at approximately midlength) 0.40 mm; sides margined, denticulate; relatively weakly produced at middle, slightly arcuate
and slightly convergent to anterior angle, very slightly sinuate and slightly convergent to posterior; anterior border
0.32 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50;
posterior border 0.36 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal foveola absent.
Anteroexternal foveolae well developed, each foveola somewhat cresent shaped, extended slightly less than 0.33 width of
anterior region of pronotum. Transverse foveola not developed, punctures in this area somewhat closer together than
punctures on disc. Disc shining, punctures fine, separated by puncture diameter; most punctures with seta extended above
cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae
separated by thin, median carina, latter sinuate line in lateral aspect. Mesosternum with internal and external carinae
divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively
narrow, sides nearly parallel; apex blunt, width at apex 0.50 distance between internal and median carinae. Metasternum
with plaques moderately developed, straight, parallel; plaques 0.43 length of metasternum in midline; width of each plaque
less than width of intercoxal process at its apex; plaques separated posteriorly by approximately four times plaque width;
plaques flat in cross section. Elytra: Length 0.72 mm. Maximum width (at midlength) 0.48 mm. Surface shining, disc with
10 rows of punctures between suture and humeral callus; most punctures round; intervals not elevated, width
approximately equal to puncture diameter, as are interstices between adjacent punctures of row; most punctures with seta.
Explanate margin quite narrow, ended near posterior 0.20, without perceptible serrations. Elytral apices, in dorsal aspect,
almost truncate; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite
elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous segments at apex only
moderately produced. Tergum 7 emarginate at apex; sternum with oval excavation on inner surface in midline. Legs:
Protibia very slightly expanded on inner surface in apical 0.33. Genitalia: Aedeagus as illustrated (Fig. 60D)(40
examined).

Natural History. - H. S. Dybas provides the label notation, “damp pockets of leaves and
debris in streambed”. Most of the specimens taken at ultraviolet light are teneral.

Distribution. - (Fig. 173). Panama, according to currently available data.

Etymology. - Latin, pontus (the open sea) plus equula (a small horse). The aedeagus has a
form reminiscent of a sea horse.

88. Hydraena sabella new species
(Figs. 59,62A,173)

Type-locality. - Eight miles W. Teapa, Chiapas, Mexico.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. My wife Maureen and I collected these specimens, May 26, 1974. Paratypes (140)
are listed in the appendix.

Diagnosis. - Adults are small, about 1.30 mm long, with plaques narrow and long, separated
by twice the width of a plaque. The aedeagus must be used to distinguish H. sabella males from
other members of the marginicollis Subgroup of similar body size and plaque configuration.

Description. — Form: Elongate. Size: Holotype 1.30 mm long, 0.52 mm wide. Color: Head with dorsal surface
black, with slight purple relections; labrum black; maxillary palpi testaceous; antennae testaceous. Pronotum testaceous at
anterior and posterior 0.22, dark brown (nearly black) in middle 0.56; sides slightly lighter than disc. Elytra brown.
Ventral surface dark brown except legs, elytral epipleura and inflexed margin of pronotum testaceous. Head: Length
0.20 mm. Width 0.35 mm. Frons moderately punctured, interstices equal to or slightly greater than puncture diameter;

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200

Perkins

surface shining. Clypeus finely microreticulate at sides, shining in middle. Labroclypeal suture straight across middle in
dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4,
respectively: 0.24/0.12/0.14; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not
especially expanded; palpomere 4 with lateral surface nearly straight, median surface arcuate; palpomere 4 widest
slightly past midlength. Mentum width equal length, surface shining, finely and sparsely punctulate. Submentum
microreticulate. Genae shining, moderately elevated; lateral area of each gena with well developed foveola; posterior
ridge absent. Postgena with punctation nearly equal that of submentum. Last five antennomeres pubsescent. Eyes
slightly larger than 0.25 interocular distance in width. Thorax: Pronotum length at midline 0.36 mm; maximum width
(at approximately midlength) 0.44 mm; sides margined, denticulate; relatively slightly produced at middle, slightly
arcuate and slightly convergent to anterior angle, very slightly concave and slightly convergent to posterior; anterior
border 0.36 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle
0.50; posterior border 0.40 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal foveola
absent. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended slightly less than 0.33
width of anterior region of pronotum. Transverse foveola absent. Disc shining, punctures fine, separated by two-three
times puncture diameter; punctures with distinctive seta extended above cuticle in dry specimens. Scintilla absent.
Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin, median carina, latter
sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to posterior;
median carina extended to base of intercoxal process; intercoxal process relatively narrow, sides tapered, apex blunt,
width at apex 0.33 distance between internal and median carinae. Metasternum with plaques well developed, straight,
nearly parallel; plaques 0.50 length of metasternum in midline; width of each plaque subequal to width of intercoxal
process at its apex; plaques separated posteriorly by approximately twice plaque width; plaques flat in cross section.
Elytra: Length 0.84 mm. Maximum width (at midlength) 0.52 mm. Surface shining, disc with 10 rows of punctures
between suture and humeral callus, rows quite regular; most punctures round; intervals not elevated, width
approximately equal to 0.50 puncture diameter, as are interstices between adjacent punctures of a row; punctures each
with seta. Explanate margin quite narrow, ended near posterior 0.12, with fine serrations near apices. Elytral apices, in
dorsal aspect, almost truncate; in posterior aspect, elytral margin elevated obliquely towards suture, in form of angle
with opposite elytron. Abdomen: Intercoxal segment flat, nearly equilateral triangle, posterior margin straight. Glabrous
segments at apex well produced. Tergum 7 emarginate at apex, sternum with internal, circular depression. Legs:
Profemur broad, with minute tubercle on inner surface near apical 0.33. Protibia excavate on inner surface at apex.
Metatibia straight, gradually enlarged to apex. Genitalia: Aedeagus as illustrated (Fig. 62A)(10 examined).

Natural History. - The stream at the type-locality is moderately large and swift,
surrounded by dense tropical vegetation (Fig. 193 A). The beetles were removed from the
sand-gravel margin.

Distribution. - (Figs. 59,173). According to the data presently available, found in the
mountains of Chiapas, Mexico and Guatemala.

Etymology. - Greek, sabella (small sand, gravel). This name refers to the microhabitat
substratum at the type-locality.

89. Hydraena d-destina new species
(Figs. 6 1 A-D,62B, 173,1 94A-B)

Type-locality. - 27 miles N. Comitan, Chiapas, Mexico.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. Two male paratypes with same data are deposited in PDP. These specimens were
collected by my wife Maureen and I, July 1, 1974.

Diagnosis. - Both sexes are characterized by their large size, about 2.00 mm long, and
plaque form, with anterior portion elevated slightly. Females are also distinguished by their
metatibiae, which are slightly expanded at midlength. Males are instantly recognized by their
greatly modified hind legs (Figs. 61A-D) which have massive femora and incredibly expanded,
triangular tibiae.

Description. — Form: Elongate. Size: Holotype 2.02 mm long, 0.86 mm wide. Color: Dorsal surface dark brown
except narrow border at anterior and posterior margins of pronotum and at elytral apices testaceous; maxillary palpi
brown; antennae brown. Ventral surface dark brown except legs, elytral epipleura and indexed margin of pronotum brown.

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201

Head: Length 0.24 mm. Width 0.46 mm. Frons moderately punctured, interstices equal to or slightly greater than
puncture diameter; surface slightly shining. Frontoclypeal suture straight. Clypeus microreticulate. Labroclypeal suture
straight across middle in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median
emargination ended slightly above midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2,
3 and 4, respectively: 0.34/0.16/0.24; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2
and 3 not especially expanded; palpomere 4 with lateral surface arcuate at base, slightly expanded at apical 0.33,
median surface sinuate; apical segment widest at apical 0.33. Mentum wider than long, surface moderately shining,
punctures relatively large and widely spaced. Submentum microreticulate. Genae shining; lateral area of each gena with
well developed foveola; posterior ridge absent. Postgena with microreticulation slightly larger than that of submentum.

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202

Perkins

Last five antennomeres pubescent. Eyes slightly less than 0.20 interocular distance in width. Thorax: Pronotum length
at midline 0.48 mm; maximum width (at approximately midlength) 0.66 mm; sides margined, denticulate; sides
moderately produced at middle, slightly arcuate and convergent to anterior angle, very slightly sinuate and convergent
to posterior; anterior border 0.50 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately
arcuate to rear in middle 0.50; posterior border 0.58 mm wide, slightly arcuate to rear. Posterointernal foveolae absent.
Interfoveolar depression weakly developed. Area between external foveolae slightly elevated. Anteroexternal foveolae
well developed, each foveola somewhat crescent shaped, extended slightly less than 0.33 width of anterior region of
pronotum. Transverse foveola not developed, punctures in this area somewhat closer together than punctures on disc.
Disc shining, punctures small and deeply impressed, separated by 0.50 puncture diameter near anterior and posterior
borders, by puncture diameter in middle; punctures with distinctive setae extended above cuticle in dry specimens.
Scintilla absent. Prosternum carinate, carina produced anteriorly into very short spine; coxae separated by thin, median
carina, latter sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to
posterior; median carina extended to base of intercoxal process; intercoxal process moderately narrow, slightly wider at
apex than at midlength, apex blunt, width at apex 0.50 distance between internal and median carinae. Metasternum
with plaques narrow, straight, convergent moderately from posterior to anterior; plaques 0.43 length of metasternum in
midline; width of each plaque 0.50 width of intercoxal process at its apex; plaques separated posteriorly by
approximately five times plaque width; most anterior limits of plaques elevated. Elytra: Length 1 .40 mm. Maximum
width (at midlength) 0.86 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus,
rows quite regular; most punctures round; intervals not elevated, width approximately equal to 0.50 puncture diameter,
as are interstices between adjacent punctures of a row; punctures each with seta. Explanate margin quite narrow, ended
near posterior 0.20, with fine, well separated serrations near anterior angles and apical 0.33; serrations closer near
apices. Elytral apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward
suture, in form of angle with opposite elytron. Right elytron distinctly shorter than left. Abdomen: Intercoxal segment
flat, wider than long, posterior margin straight. Glabrous segments at apex markedly produced, with shallow depression
in midline. Segment 7 deeply emarginate at apex. Sternum 7 with circular excavation on inner surface. Legs: Profemur
with oblique carina on inner surface near basal 0.33. Protibia expanded on inner surface in apical 0.33. Metafemur very
broad, lateral surface extremely arcuate. Metatibia greatly expanded on inner surface. Genitalia: Aedeagus as
illustrated (Fig. 62B)(3 examined).

Natural History. - These beetles were collected at the margin of a moderately rapid stream
in the mountains of Chiapas, Mexico. The substratum contained a higher percentage of mud
than is generally seen in streams supporting hydraenid populations (Figs. 194A-B).

Distribution. - (Fig. 173). Presently known only from the type-locality in the state of
Chiapas, Mexico.

Etymology. - Latin, d- (Latin equivalent of the Greek delta, i.e. triangular) plus destina
(support, prop). This name refers to the triangular metatibiae of the males (Figs. 61A-B),
which must surely serve as props during copulation.

90. Hydraena barricula new species
(Figs. 62C,173)

Type-locality. - San Cristobal de las Casas, Chiapas, Mexico.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. Paul J. Spangler collected these specimens, July 17-21, 1964.

Diagnosis. - In addition to the distinctive aedeagus (Fig. 62C), this species is characterized
by large size, about 1.84 mm long, and non-elevated plaques. Females have the metatibiae
slightly wider at the middle than at either end. Males have the inner surface of the metatibiae
angularly expanded, about 0.33 the size of that seen in H. d-destina (Fig. 61A); the outer
surface is straight, not arcuate as in H. d-destina.

Description. — Form: Elongate. Size: Holotype 1.84 mm long, 0.80 mm wide. Color: Dorsal surface of head and
disc of pronotum dark brown. Lateral areas of pronotum and elytra brown. Maxillary palpi testaceous; antennae
testaceous. Ventral surface dark brown except legs; elytral epipleura, mentum and indexed margin of pronotum brown.
Head: Length 0.24 mm. Width 0.42 mm. Frons moderately punctured, interstices equal to or slightly greater than
puncture diameter; surface shining. Frontoclypeal suture very slightly arcuate to rear. Clypeus finely microreticulate at
sides, shining in middle. Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate; each lobe

Western Hemisphere Hydraenidae

203

Figs. 61 A - H. (A-B) Hydraena d-destina, metathoracic leg of <3. (C-D) H. d-destina, prothoracic leg of <3. (E-F) H.
cuspidicollis, metathoracic leg of 3. (G-H) H. cuspidicollis, prothoracic leg of <3.

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204

Perkins

symmetrical arc; median emargination ended at approximately midlength of labrum. Maxillary palpus with following
lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.28/0.12/0.22; palpomere 2 bent outward at approximately
midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface nearly straight in
basal 0.33, slightly arcuate in apical 0.66, median surface arcuate; palpomere 4 widest near apical 0.33. Mentum wider
than long, surface moderately shining, finely punctulate. Submentum microreticulate. Genae shining; lateral area of
each gena with well developed foveola; posterior ridge absent. Postgena with microreticulation slightly larger than that
of submentum. Last five antennomeres pubescent. Eyes 0.20 interocular distance in width. Thorax: Pronotum length at
midline 0.44 mm; maximum width (at approximately midlength) 0.60 mm; sides margined, denticulate, moderately
produced at middle, slightly arcuate and convergent to anterior angle, slightly sinuate and convergent to posterior;
anterior border 0.48 mm wide, straight and nearly perpendicular to midline in lateral 0.33, moderately arcuate to rear
in middle 0.33; posterior border 0.56 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal
foveola absent. Interfoveolar depression absent. Anteroexternal foveolae well developed, each foveola somewhat crescent
shaped, extended slightly less than 0.33 width of anterior region of pronotum. Transverse foveola slightly developed,
punctures separated by approximately 0.50 puncture diameter. Disc shining, punctures moderately large and deeply
impressed, separated by puncture diameter; many punctures with short seta extended above cuticle in dry specimens.
Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated by thin, median
Carina, latter sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent from anterior to
posterior; median carina extended to base of intercoxal process; intercoxal process relatively broad, slightly wider at
apex than at midlength, apex blunt, width at apex 0.66 distance between internal and median carinae. Metasternum
with plaques well developed, curved toward midline in apical 0.33; plaques 0.50 length of metasternum in midline;
greatest width of each plaque less than width of intercoxal process at its apex; plaques separated posteriorly by
approximately three times plaque width; plaques flat in cross section. Elytra: Length 1.24 mm. Maximum width (at
midlength) 0.80 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus rows quite
regular; most punctures round; intervals not elevated, width slightly less than puncture diameter, as are interstices
between adjacent punctures of row; each puncture with seta. Explanate margin quite narrow, ended near posterior 0.17,
with fine serrations near anterior angles and apical 0.33. Elytral apices, in dorsal aspect, gradually rounded; in posterior
aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite elytron. Abdomen: Intercoxal
segment flat, nearly equilateral triangle, posterior margin very weakly arcuate. Glabrous segments at apex well
produced, arching ventrally. Tergum 7 emarginate at apex; sternum with rounded excavation on inner surface, and
corresponding rounded elevation on outer surface. Legs: Profemur with low, oblique carina on inner surface near basal
0.33. Protibia excavate on inner surface at apex. Metafemur broad, lateral surface markedly arcuate, medial surface
sinuate. Metatibia expanded on inner surface slightly past midlength. Genitalia: Aedeagus as illustrated (Fig. 62C)(1
examined).

Distribution. - (Fig. 173). Presently known only from the type-locality in the mountains of
Chiapas, Mexico.

Etymology. - Latin, barra (elephant) plus icula (diminutive). Named in reference to the
proboscis-like process of the aedeagus.

9 1 . Hydraena splecoma new species
(Figs. 62D,173,190A-B)

Type-locality. - Four miles N. Bochil, Chiapas, Mexico.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. Paratypes (12) with same data are deposited in USNM and PDP. These specimens
were collected by my wife Maureen and I, May 28, 1974.

Diagnosis. - The aedeagus must be studied to assign males to this species with complete
confidence. The plaques are well developed, on the sides of a median depression, sloped toward
the midline. Each plaque is about as wide as the mesosternal process; about twice this distance
separates the plaques from one another. Males have the protibiae expanded in the distal 0.50,
with a notch near the distal 0.33; the metatibiae are gradually enlarged from base to apex; the
abdominal apex is decidely emarginate and has a group of hairs on each side of the
emargination. The moderately large size of H. splecoma adults, about 1.78 mm long, is also of
some diagnostic aid.

Western Hemisphere Hydraenidae

205

Description. — Form: Elongate. Size: Holotype 1.78 mm long, 0.72 mm wide. Color: Head with dorsal surface and
labrum dark brown; maxillary palpi and antennae testaceous. Pronotum dark brown except for narrow testaceous border;
dark brown areas blending into testaceous areas. Elytra brown. Ventral surface dark brown except legs, elytral epipleura,
mentum and inflexed margin of pronotum brown. Head: Length 0.22 mm. Width 0.40 mm. Frons moderately punctured,
interstices equal to or slightly greater than puncture diameter; surface shining. Frontoclypeal suture straight. Clypeus
finely punctulate in middle, microreticulate at sides. Labroclypeal suture arcuate, nearly straight across middle in dorsal
aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended slightly above midlength
of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.28/0.12/0.20;
palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4
with lateral surface nearly straight, median surface arcuate; palpomere 4 widest slightly past midlength. Mentum wider
than long, surface moderately shining; punctures relatively large, separated by puncture diameter. Submentum
microreticulate. Genae moderately elevated, shining; lateral area of each gena with well developed foveola; posterior ridge
absent. Postgena with microreticulation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes
slightly less than 0.17 interocular distance in width. Thorax: Pronotum length at midline 0.44 mm; maximum width (at
approximately midlength) 0.56 mm; sides margined, denticulate; sides moderately produced at middle, slightly arcuate
and convergent to anterior angle, slightly sinuate and convergent to posterior; anterior border 0.44 mm wide, straight and
nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.52 mm wide,
slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal foveola delimited by very shallow depression with
punctation somewhat closer than that of disc, lnterfoveolar depression very slightly developed. Area between external
foveolae very weakly elevated. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended
slightly less than 0.33 width of anterior region of pronotum. Transverse foveola absent. Disc shining, punctures moderately
large, separated by 0.50 puncture diameter near anterior and posterior borders, by puncture diameter in middle; each
puncture with distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina
produced anteriorly as very short spine; coxae separated by thin, median carina, latter sinuate line in lateral aspect.
Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to base of
intercoxal process; intercoxal process relatively broad; very slightly wider at apex than at midlength, apex blunt, width at
apex slightly less than distance between internal and median carinae. Metasternum with plaques well developed, straight,
parallel; each plaque slightly wider at base than at apex; plaques 0.50 length of metasternum in midline; greatest width of
each plaque slightly less than width of intercoxal process at its apex; plaques separated posteriorly by approximately twice
plaque width; plaques on sides on median depression, sloped toward midline. Elytra: Length 1.14 mm. Maximum width (at
midlength) 0.72 mm. Surface shining, disc with 10 rows of punctures between suture and humeral callus rows quite
regular; most punctures round; intervals not elevated, width approximately equal to puncture diameter, interstices between
adjacent punctures of row slightly smaller; each puncture with distinctive seta. Explanate margin quite narrow, ended near
posterior 0.17, with prominent serrations; serrations near anterior angles and in apical 0.33; smaller near apices. Elytral
apices, in dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of
angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, posterior margin straight. Glabrous
segments at apex moderately produced. Segment 7 deeply emarginate at apex, pubescent. Legs: Profemur with oblique
carina on inner surface near basal 0.33. Protibia expanded on inner surface in apical 0.50, notched near apical 0.33.
Metatibia gradually enlarged from base to apex, extremely slightly arcuate. Genitalia: Aedeagus as illustrated
(Fig. 62D)(1 1 examined).

Natural History. - These beetles were collected at the margin of a small back water (stream
overflow) area in the mountains of Chiapas (Figs. 190A-B). The stream, which was flowing
through a pine forest, also contained Hydraena mexicana and Limnebius sinuatus.

Distribution. - (Fig. 173). Presently known only from the type-locality in the mountains of
Chiapas, Mexico.

Etymology. - Greek, splecoma (sexual intercourse). When the type-series was collected
they were placed directly into a rearing chamber in hope that they would eventually copulate
and larval stages could be obtained in due course. Much to my surprise, when the rearing
chamber was placed beneath the microscope for sorting of individuals, many of the beetles were
already in copulo. During the days that followed, each time the rearing chamber was checked a
number of copulating pairs were seen.

The geminya Subgroup

Members of the geminya Subgroup have the procoxae relatively widely separated, a small

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shelf between the coxae and median carina (Fig. 63F). Additionally, the mesosternal process is
broad, resulting in the mesocoxae being rather widely separated.

The tiny, relatively broad adults of this group are generally found on submerged plant debris
in moderately fast water, the widely separated coxae apparently an adaptation to this habitat.
All of the three species now known live in the mountains of Mexico, one each in the states of
Jalisco, Oaxaca and Chiapas.

92. Hydraena vela new species
(Figs. 64B,171A)

Type-locality. - Eleven miles SW Compostela, Nayarit, Mexico.

Type-specimen. - The holotype male (unique) is deposited in USNM. My wife Maureen
and I collected this specimen July 20, 1974.

Diagnosis. - Adults are distinguished from those of the two other members of the geminya
Subgroup now known by the narrower pronotal fascia and narrower, more widely separated
plaques. The fascia occupies the middle 0.33 of the pronotum whereas in H. geminya and H.
chiapa the fascia occupies the middle 0.50. The plaques are very narrow and widely separated,
a distance equal to about eight times the width of a plaque separating them posteriorly.

Description. — Form: Elongate-oval. Size: Holotype 1.14 mm long, 0.52 mm wide. Color: Head with dorsal surface
brown, darker near eyes; labrum brown; maxillary palpi testaceous; antennae testaceous. Pronotum with distinct, brown,
transverse macula across middle 0.33; anterior and posterior 0.33 testaceous. Elytra brown. Ventral surface brown except
legs, elytral epipleura, apex of abdomen, mentum, and inflexed margin of pronotum testaceous. Head: Length 0.16 mm.
Width 0.30 mm. Frons finely and sparsely punctured, interstices four-five times puncture diameter; surface very shiny.
Frontoclypeal suture straight. Clypeus finely microreticulate near lateral margins, shining in middle. Labroclypeal suture
straight across middle in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination
ended at approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4,
respectively: 0.20/0.08/0.16; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not
especially expanded; palpomere 4 with lateral surface nearly straight in basal 0.33, arcuate in apical 0.66, median surface
evenly arcuate; palpomere 4 widest near apical 0.33. Mentum wider than long, surface very shiny, extremely finely and
sparsely punctulate. Submentum evenly, finely punctulate, interstices equal to puncture diameter. Genae shining; lateral
area of each gena with foveola; posterior ridge absent; genae not elevated above postgena. Postgena with punctation
slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly greater than 0.20 interocular
distance in width. Thorax: Pronotum length at midline 0.28 mm; maximum width (at approximately midlength) 0.40 mm;
sides margined, extremely finely denticulate; relatively weakly produced at middle, slightly arcuate and convergent to
anterior angle, slightly arcuate and convergent to posterior; anterior border 0.32 mm wide, straight and nearly
perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.36 mm wide, slightly
arcuate to rear. Posterointernal foveolae absent. Posteroexternal foveola absent. Anteroexternal foveolae moderately
developed, each foveola somewhat crescent shaped, extended slightly less than 0.33 width of anterior region of pronotum.
Transverse foveola absent. Disc very shiny, punctures fine, separated by four-five times puncture diameter; punctures
without distinctive seta extended above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced
anteriorly as very short spine; coxae separated from median carina by thin shelf, carina sinuate line in lateral aspect.
Mesosternum with internal and external carinae divergent from anterior to posterior; median carina extended to base of
intercoxal process; intercoxal process broad, sides nearly parallel, apex blunt, width at apex equal distance between
internal and median carinae. Metasternum with plaques well developed, arcuate, convergent markedly from posterior to
anterior; plaques 0.50 length of metasternum in midline; each plaque thin, moderately elevated ridge; plaques separated
posteriorly by approximately eight times plaque width. Elytra: Length 0.72 mm. Maximum width (at midlength)
0.52 mm. Surface very shiny, punctures very small and lightly impressed, somewhat serial in first three rows (from
suture), otherwise randomly arranged; some punctures with very fine seta. Explanate margin quite narrow, ended near
posterior 0.33, with extremely fine, well separated serrations near anterior angles. Elytral apices, in dorsal aspect,
gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite
elytron. Abdomen: Intercoxal segment flat, wider than long, anterior angle broadly rounded; posterior margin straight.
Glabrous segments at apex moderately produced. Segment 7 without emargination at apex. Legs: Protibia arcuate,
expanded in apical 0.33. Metatibia gradually enlarged from base to apex. Genitalia: Aedeagus as illustrated (Fig. 64B)(1
examined).

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Natural History. - This specimen was taken from a tropical stream which also contained
Limnebius mitus and Spanglerina frondsicola.

Distribution. - (Fig. 171 A). Presently known only from the type-locality in the hills of
Nayarit, Mexico.

Etymology. - Latin, vela (sail). The aedeagus has a large sail-like structure.

93. Hydraena chiapa new species
(Figs. 64C,171 A,192A-B)

Type-locality. - Nine miles N. Tapilula, Chiapas, Mexico.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. My wife Maureen and I collected these specimens. May 27, 1974. One male and
three female paratypes from the same locality are deposited in PDP. One male and five female
paratypes (CNC) have the following data: Ocosingo, Chiapas, 2-VI-69, Bright and Campbell.

Diagnosis. - Very similar externally to H. geminya, differing in plaque configuration and
aedeagus. The plaques are nearly parallel, separated at anterior by more than the length of a
plaque.

Description. — Form: Elongate-oval. Size: Holotype 1.24 mm long, 0.64 mm wide. Color: Head with dorsal surface
dark brown; labrum dark brown; maxillary palpi testaceous; antennae testaceous. Pronotum with a distinct, brown,
transverse macula across middle 0.50; anterior and posterior 0.25 testaceous. Elytra brown. Ventral surface brown except
legs, elytral epipleura, apex of abdomen, mentum, and inflexed margin of pronotum testaceous. Head: Length 0.18 mm.
Width 0.34 mm. Frons finely and sparsely punctured, interstices two-three times puncture diameter; surface shining.
Frontoclypeal suture straight. Clypeus finely punctulate near lateral margins, shining in middle. Labroclypeal suture
arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at
approximately midlength of labrum. Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively:
0.20/0.08/0.16; palpomere 2 bent outward at approximately midlength; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface weakly arcuate, median surface more strongly arcuate; palpomere 4 widest
slightly past midlength. Mentum wider than long, surface shining, finely and sparsely punctulate. Submentum evenly,
finely punctulate, punctures contiguous. Genae shining, extremely slightly elevated; lateral area of each gena with well
developed foveola; posterior ridge absent. Postgena with punctation slightly larger than that of submentum. Last five
antennomeres pubescent. Eyes slightly less than 0.25 interocular distance in width. Thorax: Pronotum length at midline
o.32 mm; maximum width (at approximately midlength) 0.46 mm; sides margined, denticulate; sides relatively slightly
produced at middle, slightly sinuate and slightly convergent to anterior angle, slightly sinuate and slightly convergent to
posterior; anterior border 0.38 mm wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate
to rear in middle 0.50; posterior border 0.42 mm wide, slightly arcuate to rear. Posterointernal foveolae absent.
Posteroexternal foveola very slightly developed. Anteroexternal foveolae moderately developed, each foveola somewhat
crescent shaped, extended slightly less than 0.33 width of anterior region of pronotum. Transverse foveola absent. Disc
shining, punctures fine, separated by two-three times puncture diameter; most punctures without distinctive seta extended
above cuticle in dry specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae
separated from median carina by shelf twice width of carina, latter sinuate line in lateral aspect. Mesosternum with
internal and external carinae divergent from anterior to posterior; median carina extended to base of intercoxal process;
intercoxal process very broad, sides parallel, apex blunt, width at apex greater than distance separating internal and
median carinae. Metasternum with plaques well developed, straight, convergent moderately from posterior to anterior;
plaques nearly 0.50 length of metasternum in midline; width of each plaque nearly 0.50 width of intercoxal process at its
apex; plaques separated posteriorly by approximately 1.5 plaque width; plaques separated anteriorly by plaque width;
plaques flat in cross section. Elytra: Length 0.80 mm. Maximum width (at midlength) 0.64 mm. Surface shining, disc with
first four rows (from suture) of punctures fairly distinct, other punctures more or less randomly arranged; punctures very
fine, interstices two-three times puncture diameter; some punctures with very fine seta. Explanate margin quite narrow,
ended near posterior 0.33 with extremely fine, well separated serrations near anterior angles. Elytral apices in dorsal aspect
gradually rounded; in posterior aspect, elytral margin elevated obliquely toward suture, in form of angle with opposite
elytron. Abdomen: Intercoxal segment flat, wider than long; anterior angle broadly rounded; lateral angles acute; posterior
margin straight. Glabrous segments at apex moderately produced. Segment 7 without emargination at apex. Legs: Protibia
slightly arcuate. Metatibia gradually enlarged to apex. Genitalia: Aedeagus as illustrated (Fig. 64C)(3 examined).

Natural History. - Specimens from the type-locality were on leaves and twigs trapped
behind rocks in a tropical brook (Figs. 192A-B). They were in association with Spanglerina

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Figs. 62A - D, Aedeagi of Hydraena holotypes. (A) H. sabella. (B) H. d-destina. (C) H. barricula. (D) H. splecoma.

brevis.

Distribution. - (Fig. 171 A). Presently known only from the mountains of Chiapas, Mexico.
Etymology. - chiapa , in reference to the geographical distribution.

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94. Hydraena geminya new species
(Figs. 63A,C,E-G,64D,171A)

Type-locality. - Four miles S. Valle Nacional, Oaxaca, Mexico.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. Paratypes (19) from the same locality are deposited in USNM, CAS and PDP. My
wife Maureen and I collected these specimens July 6, 1974.

Diagnosis. - Distinguished from other members of the geminya Subgroup by the plaques,
which are convergent anteriorly, separated at anterior by less than the length of a plaque.
Externally adults are very similar to thse of H. chiapa, differences in the plaque configuration
being rather slight in comparison to differences in the aedeagi (Figs. 64C-D).

Description. — Form: Elongate-oval. Size: Holotype 1.18 mm long, 0.56 mm wide. Color: Head with dorsal surface
and labrum dark brown; maxillary palpi and antennae testaceous. Pronotum testaceous at anterior and posterior 0.25, dark
brown in middle 0.50; sides slightly lighter than middle. Elytra brown. Ventral surface brown except legs, elytral
epipleura, mentum, abdominal apex and inflexed margin of pronotum testaceous. Head: Length 0.18 mm. Width 0.32 mm.
Frons finely and sparsely punctured, interstices three-four times puncture diameter; surface shining. Frontoclypeal suture
straight. Clypeus finely punctulate at sides, shining in midline. Labroclypeal suture arcuate in dorsal aspect. Labrum
bilobed, microreticulate, each lobe symmetrical arc; median emargination ended at approximately midlength of labrum.
Maxillary palpus with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.20/0.08/0.16; palpomere 2 bent
outward at approximately midlength; apices of palpomere 2 and 3 not especially expanded; palpomere 4 with lateral
surface very slightly arcuate, median surface arcuate; palpomere 4 widest near midlength. Mentum wider than long,
surface shining, finely and sparsely punctulate. Submentum evenly, finely punctulate, punctures contiguous. Genae
shining, extremely slightly elevated; lateral area of each gena with well developed foveola; posterior ridge absent. Postgena
with punctation slightly larger than that of submentum. Last five antennomeres pubescent. Eyes slightly less than 0.25
interocular distance in width. Thorax: Pronotum length at midline 0.30 mm; maximum width (at approximately
midlength) 0.44 mm; sides margined, denticulate, relatively weakly produced at middle, slightly arcuate and slightly
convergent to anterior angle, slightly sinuate and slightly convergent to posterior; anterior border 0.36 mm wide, straight
and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.40 mm
wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal foveola extremely weakly developed.
Interfoveolar depression absent. Anteroexternal foveolae well developed, each foveola somewhat crescent shaped, extended
slightly less than 0.33 width of anterior region of pronotum. Transverse foveola absent. Disc shining, punctures fine and
sparse, separated by three-four times puncture diameter; few punctures with indistinct setae extended above cuticle in dry
specimens. Scintilla absent. Prosternum carinate, carina produced anteriorly as very short spine; coxae separated from
median carina by shelf slightly wider than carina, latter sinuate line in lateral aspect. Mesosternum with internal and
external carinae divergent from anterior to posterior; median carina extended to base of intercoxal process; intercoxal
process very broad, sides parallel, apex blunt, width slightly greater than distance between internal and median carinae.
Metasternum with plaques well developed, straight, convergent moderately from posterior to anterior; plaques 0.50 length
of metasternum in midline; width of each plaque 0.33 width of intercoxal process; plaques separated posteriorly by
approximately twice plaque width; plaques flat in cross section. Elytra: Length 0.76 mm. Maximum width (at midlength)
0.56 mm. Surface shining, disc with first three rows (from suture) of punctures fairly distinct, other punctures more or less
randomly arranged; punctures very fine, interstices two-four times puncture diameter; most punctures with very fine seta.
Explanate margin quite narrow, ended near posterior 0.20, with extremely fine serrations near^anterior angles. Elytral
apices, in dorsal aspect, gradually rounded; viewed posteriorly, elytral margin elevated obliquely toward suture, in form of
angle with opposite elytron. Abdomen: Intercoxal segment flat, wider than long, anterior angle rounded; posterior margin
straight. Glabrous segments at apex only moderately produced. Segment 7 without emargination at apex. Legs: Protibia
slightly arcuate. Metatibia slightly wider at midlength than at apex. Genitalia: Aedeagus as illustrated (Fig. 64D)(9
examined).

Natural History. - These beetles were removed from twigs, leaves and other debris taken
from a small tropical cascade. Consocies included Spanglerina brevis and Elmoparnus pandus
(see Spangler and Perkins, 1977, figure 19).

Distribution. - (Fig. 171 A). Presently known only from the type-locality in the mountains of
Oaxaca, Mexico.

Etymology. - geminya , a miscellaneous assemblage of letters.

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Figs. 63A - G. (A) Hydraena geminya 6, ventral habitus. (B) H. pontequula <5, ventral habitus. (C) H. geminya <5,
abdominal apex. (D) H. pontequula , deformed metatibia. (E) H. geminya , metasternum. (F) H. geminya, pro- and
mesosternum. (G) H. geminya, head, ventral aspect.

The paeminosa Group

Adults of the single species from Surinam included herein, H. paeminosa , possess an
unusual set of characteristics which justify separation of this species from the remainder of

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211

Western Hemisphere Hydraena. The aedeagus (Fig. 95D) has the parameres greatly reduced
and attaching near the apex of the main-piece, a trait one might associate with tropical lineages
of the genus. However, there is a well developed posterior ridge of the genae similar to that seen
in the dominant nearctic lineage ( circulata Group). The pronotum is most similar to that of
circulata Group adults, but differs in that it is widest before midlength instead of at or near
midlength. Finally, the elytral punctures are well developed and totally random, a condition
absent from circulata Group adults.

95. Hydraena paeminosa new species
(Figs. 95D,160)

Type-locality. - Carolina Creek, 10 kilometers from Zanderij, Surinam.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. Paratypes from same locality are deposited in USNM (5 males) and PDP (1 male, 1
female). These specimens were collected by Borys Malkin, November 18, 1962. Additional
paratypes (2 males, 2 females) with the following data are also deposited in USNM:
Krakka-Phedra Rd., Surinam, November 25, 1962, B. Malkin.

Diagnosis. - Coarsely punctate, markedly microreticulate pronotum which is rather
elongate plus the coarse, non-serial elytral punctation serve as diagnostic features for H.
paeminosa. The intercoxal abdominal sternum is concave and the genae possess a posterior
ridge, contrary to the remaining South American Hydraena adults.

Description. — Form: Elongate. Size: Holotype 1.64 mm long, 0.72 mm wide. Color: Entirely dark brown except
mentum, maxillary palpi and antennae brown. Head: Length 0.22 mm. Width 0.40 mm. Frons moderately punctured,
interstices with close, fine, impressed lines, surface dull. Frontoclypeal suture arcuate to rear. Clypeus microreticulate.
Labroclypeal suture arcuate in dorsal aspect. Labrum bilobed, microreticulate, each lobe symmetrical arc; median
emargination wide, ended slightly above midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.32/0.16/0.22; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 extremely slender in basal 0.33, apical 0.66 lateral surface
slightly arcuate, median surface slightly more arcuate; palpomere 4 widest near apical 0.33. Mentum wider than long,
surface moderately shining, finely punctulate. Submentum finely punctulate, somewhat inflated. Genae dull; lateral area
of each gena with well developed foveola; posterior ridge well developed. Postgena with punctation slightly larger than that
of submentum. Last five antennomeres pubescent. Eyes 0.25 interocular distance in width. Thorax: Pronotum length at
midline 0.40 mm; maximum width (slightly posterior to midlength) 0.50 mm; sides margined, denticulate; sides relatively
slightly produced at middle, concave and slightly convergent to anterior and posterior angles, anterior border 0.44 mm
wide, straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior
border 0.46 mm wide, slightly arcuate to rear. Posterointernal foveolae absent. Posteroexternal and anteroexternal foveolae
confluent, in form of explanate sides of pronotum. Disc dull, punctures moderately large and close together, interstices
microreticulate; surface dull; most punctures with seta extended above cuticle in dry specimens. Scintilla absent.
Prosternum carinate, carina produced anteriorly as very short spine, width of carina between coxae three times width of
carina anterior to coxae; carina sinuate line in lateral aspect. Mesosternum with internal and external carinae divergent
from anterior to posterior; median carina extended to base of intercoxal process; intercoxal process relatively narrow, sides
nearly parallel, apex rounded, width near apex slightly less than 0.50 distance between internal and median carinae,
subequal distance between procoxae. Metasternum with median ridge posterior to intercoxal process, ridge ended near
anterior region of plaques; plaques well developed, straight, somewhat triangular, convergent moderately from posterior to
anterior; plaques 0.57 length of metasternum in midline; greatest width of each plaque subequal width of intercoxal
process at its midlength; plaques separated posteriorly by approximately daque width; plaques flat in cross section.
Excavation posterior to middle coxal cavities well developed. Elytra: Length 1.10 mm. Maximum width (at midlength)
0.72 mm. Punctures large, close together and random; interstices somewhat uneven; surface dull; most punctures with seta.
Explanate margin quite narrow, ended near posterior 0.20, with extremely fine serrations near apices. Elytral apices, in
dorsal aspect, gradually rounded; in posterior aspect, elytral margin elevated very slightly, obliquely toward suture, in form
of weak angle wih opposite elytron. Abdomen: Intercoxal segment concave; posterior margin arcuate. Glabrous segments
at apex not produced, flat, width twice length. Segment 7 without emargination at apex. Legs: Protibia slightly arcuate.

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Mesotibia slightly constricted at base, with conspicuous pubescence. Metatibia very slightly expanded on inner surface
near apical 0.33. Genitalia: Aedeagus as illustrated (Fig. 95D)(9 examined).

Natural History. - The label notation, “waterholes from drying up forest stream with
gravelly bottom” accompanies the specimens from the type-locality.

Distribution. - (Fig. 160). Presently known only from Surinam, near Zanderij.

Etymology. - Latin, paeminosa (uneven, rough). This name refers to the dull dorsal
surface, which is coarsely punctate and markedly microreticulate, especially on the pronotum.

GENUS SPANGLERINA, NEW GENUS

Type of the genus: Spanglerina ingens , new species. Gender:feminine.

Discussion. - This new genus is erected for four species of Central American hydraenines
whose adults are unique in several external characteristics, both dorsal and ventral, aedeagal
structure, and habitat preferences. Adults of Spanglerina possess elongate maxillary palpi
characteristic of Hydraena species, but differ from members of that genus in many respects.
Significantly, these differences do not indicate a sister-group relationship with any of the
sublineages of Hydraena (i.e., circulata, leechi or marginicollis Groups, or the subgenus
Haenydra ), but are a curious mixture of features, some of which characterize the circulata
Group, some more similar to the leechi and marginicollis Groups, while several others are
unique.

The ventral surface of the head has a well defined genal ridge (Fig. 65D), as do members of
the circulata Group of Hydraena , but the aedeagus (Figs. 67A-D) is extremely complex and
the intercoxal segment of the abdomen is flat, features indicative of the leechi or marginicollis
Groups of Hydraena. However, although the aedeagus is complex, its basic plan is quite
different from any species in the leechi or marginicollis Groups, having both parameres
originating near the base, the left paramere broadly expanded and in form of a large cup in
which the complex terminal piece rests. This expanded left paramere possibly provides support
to the main-piece and terminal apparatus during copulation, a function unknown in Hydraena.

Although the intercoxal sternum of the abdomen is flat, as it is in species of the leechi and
marginicollis Groups of Hydraena , it is markedly transverse, more than twice as long as wide,
whereas those of Hydraena adults are triangular (Figs. 57B,65C) and not as wide.

Of course the wide intercoxal sternum of Spanglerina is related to the widely spaced hind
coxae, but it also is related to another, internal feature which differs from Hydraena adults, the
form of the metendosternite. In most Hydraena adults the metendosternite is “Y” shaped,
whereas in Spanglerina the “stem” of the “Y” is absent, and the “arms” attach to the base to
form a “U” shape.

The widely separated hind coxae are probably related to the unusual habitat preferences of
this genus, as are the relatively widely spaced pro- and mesocoxae and the short, dense
hydrofuge pubescence (Figs. 65C-D). As discussed in more detail in the “Natural History”
section, species of Spanglerina are typically found clinging to twigs and other plant debris
which become trapped behind emergent rocks in rapid tropical streams. Widely separated
coxae are also seen in elmids and presumably enhance a beetle’s ability to cling to the
substratum in fast water.

This habitat type is quite different from that used by the great majority of Hydraena (or the
majority of the family, for that matter) which is generally the sand- gravel margins of streams
(see Perkins, 1976). An exception to this general rule are the three species of the geminya

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213

Figs. 64A - D, Aedeagi of Hydraena holotypes. (A) H. hyalina (B) H. vela. (C) H. chiapa. (D) H. geminya.

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Figs. 65 A - G, Spanglerina brevis, 6. (A) dorsal habitus. (B) ventral habitus. (C) metasternum. (D) pro- and
mesosternum. (E) pronotum (A1F = anterointernal foveola, AEF = anteroexternal foveola, LF = lateral furrow, AC =
anterior callosity, MR = median ridge, PC = posterior callosity, PEF = posteroexternal foveola, PIF = posterointernal
foveola). (F) head, ventral aspect. (G) abdominal apex.

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215

Subgroup of Hydraena. These three species also have the coxae relatively widely separated
(Figs. 63A,F), and I have collected many of them in association with Spanglerina individuals
while sorting through water-soaked plant debris taken from rapidly flowing tropical streams,
brooks and cascades. The habitus and all other characteristics of the geminya Subgroup
species, however, clearly demonstrate that they are a sublineage of the marginicollis Group of
Hydraena , and that the relatively widely spaced coxae is an indication of convergence with, not
relationship to, Spanglerina.

Another unusual ventral characteristic is the foveae near the anterior margin of the mentum
(Fig. 65 F) in Spanglerina adults. These foveae have not been seen in any other genus of the
Hydraeninae.

Dorsally, Spanglerina adults present a distinctive habitus appearance due to the
subcordiform pronotum which is markedly produced at the sides, broadly explanate elytra, and
rough sculpture (Figs. 65A,E). The pronotum is also unusual in having a slightly elevated
median ridge and shallow, rather indistinctly defined anterointernal foveolae. Neither of these
features are seen in Hydraena.

Consequently, based upon the unusual dorsal, ventral, internal and aedeagal characteristics
and habits mentioned above, I conclude that this group represents a phylogenetic lineage
separate from and not arising within Hydraena , and am therefore affording it equal, generic
rank.

Etymology. - I take great pleasure in naming this new genus in honor of Dr. Paul J.
Spangler, in recognition of his many and continuing contributions to the knowledge of aquatic
Coleoptera.

Pronotal Features. - The major relief features of Spanglerina pronota (Fig. 65E) consist of
antero- and posterointernal foveolae (AIF and PIF), antero- and posteroexternal foveolae
(AEF and PEF), lateral furrows (LF), anterior and posterior callosities (AC and PC), and a
median ridge (MR).

Diagnosis. - Adults are readily distinguished from those of Hydraena , the only other genus
with comparably elongate maxillary palpi, by the widely spaced, rather globose coxae
(Figs. 65C-D), and the rough, subcordiform pronotum with low median ridge and indistinctly
defined anterointernal foveolae (Fig. 65E). The foveae near the anterior margin of the mentum
(Fig. 65F) are also diagnostic.

Description. — Form: Ovate, moderately convex (Fig. 65A) Size: Length 1.65 -2.00 mm, width 0.80 - 0.97 mm.
Color: Reddish brown to dark brown, head sometimes bicolored, frons dark brown, clypeus and labrum reddish. Head:
Coarsely punctate, markedly microreticulate dorsally. Clypeus transverse, sides convergent anteriorly. Labrum bilobed.
Maxillary palpus elongate, length of palpomere 2 equal to combined lengths of palpomeres 3 and 4. Mentum rectangular,
with four foveae near anterior margin. Genae with posterior ridge. Antennomeres nine (4 + 5). Thorax: Pronotum widely
produced at sides, subcordiform, coarsely punctate and markedly microreticulate; disc with well developed posterointernal
foveolae, slightly developed anterointernal foveolae and median ridge; postero- and anteroexternal foveolae well developed;
groove at sides of pronotum well developed. Prosternum elevated between coxae, latter relatively widely separated.
Mesosternum with intercoxal process relatively wide and with slightly elevated median ridge. Metasternum covered with
dense, short hydrofuge pubescence, except glabrous, narrow and carinate plaques. Elytra: Disc with 10 rows of large
punctures between suture and humeral callus, rows striate-impressed. Explanate margin well developed. Abdomen: Basal
four sterna and anterior portion of fifth with hydrofuge pubescence, remainder with sparse hairs. Intercoxal segment
transverse, more than twice as long as wide. Legs: Of moderate build. Males with protibia enlarged near apex, metatibia
frequently expanded and with brush of hairs. Genitalia: Aedeagus with left paramere expanded, partially surrounding
terminal piece.

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Key to Western Hemisphere species of Spanglerina

1 ( 0 ) Head unicolorous black; size larger, about 1.72 - 1.92 mm ( ingens Group) ... 2

r Head bicolored, frons black, clypeus reddish; size smaller, about 1.60 - 1.66 mm

{brevis Group) 3

2 ( 1 ) Posterointernal foveolae less developed, punctures as distinct as those on reliefs;

median ridge at anterior and posterior of pronotum, absent from middle; size

about 1.92 mm; aedeagus as illustrated (Fig. 67D); Mexico, Mexico

S. ingens, new species, p. 216

2' Posterointernal foveolae more developed, punctures less distinct than those on
reliefs; median ridge present for entire length of pronotum; size about 1.72 mm;

aedeagus as illustrated (Fig. 67C); Oaxaca, Mexico

S.fluvicola, new species, p. 218

3 ( 1') Plaques extended further posteriorly; metatibial brush of males less developed,

hairs against tibia (Figs. 66C,G); large punctures in posterointernal foveolae
more apparent; aedeagus as illustrated (Fig. 67A); Colima, Mexico south to

Honduras S. brevis (Sharp), p. 220

3' Plaques shorter, about 0.50 length of above species (see Fig. 65C); metatibial
brush of males well developed, hairs extended from surface of tibia
(Figs. 66A-B); punctures in posterointernal foveolae less apparent; aedeagus as

illustrated (Fig. 67B); Nayarit and Jalisco, Mexico

S.frondsicola , new species, p. 221

The ingens Group

Members of this Group are large, about 1.70 - 1.90 mm long, and unicolorous dark brown or
black. The metasternal plaques are thin, distinctly elevated, triangular carinae which are
widely separated one from the other and situated about midway between the middle and hind
coxae. Two Mexican species are currently known for the Group, one from the state of Mexico,
the other from Oaxaca. Males have the metatibiae expanded near the apex and with a small
brush of hairs (Figs. 66D,E,H-I).

1 . Spanglerina ingens new species
(Figs. 66D,E,H,I,67D,68A,174,197B)

Type-locality. - Eleven miles S. Valle de Bravo, Mexico, Mexico.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. Eight paratypes (6 male, 2 female) with same data are deposited in PDP. These
specimens were collected by my wife Maureen and I, July 12, 1974. Two male paratypes
(BMNH) have the following data: Mexico, Temescaltepec, Real de Arriba, 6-7000 feet, May,
1933, H. E. Hinton and R. L. Usinger.

Diagnosis. - Distinguished from other members of the genus by large size (1.92 x 0.96 mm),
distinctly punctate posterointernal foveolae, broadly explanate elytra, and aedeagal form.

Description. — Form: Ovate. Size: Holotype 1.92 mm long, 0.96 mm wide. Color: Entire dorsal surface dark
brown; maxillary palpi light brown. Ventral surface dark brown, except legs, elytra! epipleura and abdominal apex, brown.
Head: Length 0.28 mm. Width 0.48 mm. Frons coarsely punctured: interstices 0.33 puncture diameter, flat and dull;

Western Hemisphere Hydraenidae

217

Figs. 66 A - I, Spanglerina , legs of males. (A-B) S.frondsicola , metathoracic leg. (C) S. brevis , metathoracic leg. (D-E)
S. ingens , metathoracic leg. (F) S. brevis , protibia. (G) S. brevis, metathoracic leg. (H-I) S. ingens, metathoracic leg.

microreticulation extremely fine; deep foveola median to each eye, extended to labroclypeal suture. Frontoclypeal suture
recurved, markedly arcuate to rear in midline. Clypeus microreticulate. Labrociypeal suture straight, with clearly
defined lateral angles. Labrum bilobed, constricted at base, microreticulate, anterior margin with conspicuous setae;
each lobe asymmetrical, sides of median emargination straight, ended well above midlength of labrum. Maxillary palpus
with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.32/0.12/0.18; palpomere 2 nearly evenly arcuate;
apices of palpomeres 2 and 3 not especially expanded; palpomere 4 lateral surface slightly sinuate, with indented portion
of sinuation at basal 0.33, median surface arcuate, with apex of curve at basal 0.33, palpomere 4 widest at
approximately midlength. Mentum wider than long, with large depressions near anterior margin, otherwise punctulate.

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Perkins

Submentum shining at apex, rugulose at base. Genae moderately shining, with fine punctures; lateral area of each gena
with well developed foveola; posterior margin of each gena with ridge. Last five antennomeres pubescent. Eyes slightly
less than 0.20 interocular distance in width. Thorax: Pronotum length at midline 0.46 mm; Maximum width (slightly
before midlength) 0.74 mm; sides not margined, denticulate, markedly produced at middle, slightly arcuate and
markedly convergent to anterior angles, arcuate and markedly convergent to posterior 0.17, thence parallel to midline to
posterior angles; anterior border 0.56 mm wide, nearly straight and nearly perpendicular to midline in lateral 0.25,
moderately arcuate to rear in middle 0.50; posterior border 0.50 mm wide, arcuate to rear; surface with deep punctures
and extremely fine microreticulation, latter quite evident on interstices; punctures without perceptible setae;
posterointernal foveolae slightly developed, shallow, with punctures as well defined as those on callosities; anterointernal
foveolae similar in appearance to posterointernal; posterior callosities moderately developed; anterior callosities very
slightly developed; median ridge between internal foveolae, absent from center of pronotum; posteroexternal foveolae
clearly developed, separated partially from lateral furrows by lateral callosities; anteroexternal foveolae clearly
developed, separated from lateral furrows by narrow ridge. Prosternum slightly carinate, produced to point between
coxae, not produced anteriorly as spine; coxae widely separated. Mesosternum with internal and external carinae
divergent from anterior to posterior; median carina ended near base of intercoxal process; intercoxal width at apex 0.66
width between internal and median carinae, with median, longitudinal ridge. Metasternum without low ridge posterior
to intercoxal process; plaques acute, triangular in lateral view, midway between mid and hind coxae; plaques separated
by 0.64 length of metasternum; a shallow furrow lateral to each plaque. Elytra: Length 1 .26 mm. Maximum width (at
midlength) 0.80 mm. Surface moderately dull, disc with 10 rows of deeply impressed punctures between suture and
humeral callus, rows very straight; intervals slightly elevated, width 0.66 puncture diameter; interstices between
adjacent punctures of row slightly less than interval width; intervals and interstices with various reflections, surface
uneven; many punctures with small seta at anterior side (puncture centers obscured by debris). Explanate margin wide,
extended to elytral apices, denticulations at anterior angles, remainder with fine serrations. Elytral apices, in posterior
aspect, slightly arcuate to ventral surface. Abdomen: Intercoxal segment transverse, glabrous. Segment 7 with
emargination at apex (male). Legs: Protibial median surface slightly arcuate, flat area on posterior surface near apex,
with prominent spine at base. Mesotibiae with median surface arcuate at apical 0.66. Metatibia arcuate in apical 0.50,
and expanded at apex (Figs. 66D,E,H-I). Genitalia: Aedeagus as illustrated (Fig. 67D)(9 examined).

Variation. - The hind tibiae of males (Figs. 66D,E,H-I) have the basal region expanded,
slightly arcuate, and bearing a brush of hairs. Females lack these tibial modifications.
Additionally, the carinate plaques are distinctively higher in males than in females.

Natural History. - The stream at the type-locality flows through a deciduous-pine forest,
and was choked with leaf debris (Fig. 197B). The beetles were found by spreading the wet
debris on a cloth and allowing it to dry. Specimens of Ochthebius obscurus and Hydraena
scintilla were also collected at this stream.

Distribution. - (Figs. 68A,174). Presently known only from the state of Mexico, Mexico.

Etymology. - Latin, ingens (huge). This name refers to the large size of adults of this
species.

2. Spanglerina fluvicola new species
(Figs. 67C,68A, 174,1 95B-C)

Type-locality. - One mile N. Ixtlan de Juarez, Oaxaca, Mexico.

Type-specimen. - The holotype male (unique) is deposited in USNM. My wife and I
collected this specimen August 5, 1974.

Diagnosis. - Quite similar in most respects to S. ingens adults, but smaller (1.72 vs
1.92 mm), and with the pronotum less produced at the sides. Depressions of the pronotum are
markedly microreticulate, obscuring the punctation, whereas large punctures are quite evident
on the reliefs. In S. ingens adults the punctures are equally evident in the depressions and on
the reliefs. The metatibiae of S. fluvicola adults are of a similar shape to those of S. ingens
(Figs. 66D,E,H-I), but apparently lack the brush of hairs present on the latter. The aedeagi of
males of the two species (Figs. 67C-D) are of a different form.

Description. — Form: Ovate. Size: Holotype 1.72 mm long, 0.84 mm wide. Color: Dorsal surface with head dark
brown, nearly black; pronotum dark brown except lighter areas at anterior and posterior borders; elytra brown except

Western Hemisphere Hydraenidae

219

explanate margin light brown. Maxillary palpi testaceous. Ventral surface dark brown except legs, elytral epipleura and
anterior region of mentum brown. Head: Length 0.28 mm. Width 0.44 mm. Frons coarsely punctured; interstices 0.33
puncture diameter, flat and dull; microreticulation extremely fine; deep foveola median to each eye, extended to
labroclypeal suture. Frontoclypeal suture recurved, markedly arcuate to rear in midline. Clypeus microreticulate.
Labroclypeal suture straight, with well defined lateral angles. Labrum bilobed, constricted at base, microreticulate;
anterior margin with conspicuous setae; each lobe asymmetrical, sides of median emargination straight; median
emargination ended above midlength of labrum. Maxillary palpu^ with following lengths (mm) of palpomeres 2, 3 and
4, respectively: 0.28/0.10/0.24; palpomere 2 nearly evenly arcuate; apices of palpomeres 2 and 3 not especially
expanded; palpomere 4 with lateral surface slightly sinuate, indented portion of sinuation at basal 0.33, median surface
arcuate, apex of curve at basal 0.33; apical segment widest at approximately midlength. Mentum subquadrate, large
depressions near anterior margin, otherwise microreticulate. Submentum shining at apex, microreticulate at base. Genae
moderately shining, with fine punctures; lateral area of each gena with well developed foveola; posterior margin of each
gena with ridge. Last five antennomeres pubescent. Eyes slightly less than 0.20 interocular distance in width. Thorax:
Pronotum length at midline 0.40 mm; maximum width (slightly before midlength) 0.62 mm; sides not margined,
denticulate, markedly produced at middle, slightly arcuate and markedly convergent to anterior angles, arcuate and
markedly convergent to posterior 0.17, thence parallel to midline to posterior angles; anterior border 0.48 mm wide,
nearly straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior
border 0.42 mm wide, arcuate to rear; surface with large, deep punctures and extremely fine microreticulation, latter
quite evident in foveolae; punctures without perceptible seta; posterointernal foveolae well developed, punctures less
distinct than those of callosities; anterointernal foveolae less developed than posterointernal, punctures more apparent;
posterior callosities well developed; anterior callosities slightly developed; median ridge evident for entire length of
pronotum; posteroexternal foveolae well developed, separated partially from lateral furrows by lateral callosities;
anteroexternal foveolae well developed, separated from lateral furrows by narrow ridge. Prosternum slightly carinate,
produced to point between coxae, not produced anteriorly as spine; coxae widely separated. Mesosternum with internal
and external carinae divergent from anterior to posterior; median carina ended near base of intercoxal process;
intercoxal width at apex 0.66 width between internal and median carinae, with median, longitudinal ridge.
Metasternum without low ridge posterior to intercoxal process; plaques acute, triangular, approximately midway
between mid and hind coxae; plaques separated by 0.66 metasternal length in midline; shallow furrow lateral to each
plaque. Elytra: Length 1.16 mm. Maximum width (at midlength) 0.82 mm. Surface moderately dull, disc with 10 rows
of deeply impressed punctures between suture and humeral callus, rows very straight; intervals slightly elevated, width
0.66 puncture diameter; interstices between adjacent punctures of row slightly less than interval width; intervals and
interstices with various reflections, surface uneven; many punctures with small seta at anterior side. Explanate margin
wide, extended to elytral apices, denticulations at anterior angles, remainder with fine serrations. Elytral apices, in
posterior aspect, slightly arcuate to ventral surface. Abdomen: Intercoxal segment transverse, glabrous. Segment 7 with
emargination at apex (male). Legs: Protibial median surface slightly arcuate, flat area on posterior surface near apex,
without large basal spine. Mesotibia with median surface arcuate in apical 0.66. Metatibiae arcuate in apical 0.50, and
expanded at apex. Genitalia: Aedeagus as illustrated (Fig. 67C)(1 examined).

Natural History. - The type-specimen was removed from a small submerged log, which was
about two feet below the surface of a rapid stream (Figs. 195B-C).

Distribution. - (Fig. 174). Presently known only from the type-locality at the base of the
mountains north of Oaxaca, Mexico.

Etymology. - Latin, fluvidus (flowing) plus icola (dweller). Named in reference to the
habitat of the type-specimen.

The brevis Group

Adults of the brevis Group are moderate sized, about 1.60 - 1.70 mm long, with the head
bicolored, frons dark brown or blackish and clypeus and labrum reddish. Metasternal plaques
are elongate carinae (Fig. 65C), not markedly elevated and triangular as in ingens Group
adults. Males have the metatibiae with a patch of hairs near the distal end which either form a
brush (Fig. 66B) or are flat against the leg (Fig. 66G); the metatibia, however, is not expanded
to the degree seen in ingens Group adults. Two species are now known for the brevis Group, one
(S. brevis ) with an extensive distribution in Mexico and Central America, the other ( S .
frondsicola) apparently restricted to Nayarit and Jalisco, Mexico.

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Perkins

3. Spanglerina brevis (Sharp)

(Figs. 10H,65A-G,66C,F-G,67A,68B,174,196A-C)

Hydraena brevis Sharp, 1882:94 (lectotype female deposited in BMNH, herein designated; new combination;

type-locality: San Joaquin, Baja Verapaz, Guatemala).

Diagnosis. - Differs from S. frondsicola , the only other member of the brevis Group, by the
longer plaques and aedeagal form. Additionally, the metatibial brush of males (Figs. 66A-C,G)
is different in the two species; in S. brevis adults, the brush is less developed, hairs against the
tibia, whereas in S. frondsicola adults, the hairs are more apparent, extended away from the
surface of the tibia.

Description. — Form: Ovate. Size: Lectotype 1 .66 mm long, 0.80 mm wide. Color: Head bicolored, frons dark
brown, clypeus reddish brown; labrum bilobed; maxillary palpi light brown; antennae light brown. Pronotum and elytra
brown, slightly reddish. Ventral surface reddish brown. Head: Length 0.24 mm. Width 0.42 mm. Frons coarsely
punctured, interstices flat, slightly less than puncture diameter; deep foveola median to each eye, extended to labroclypeal
suture. Frontoclypeal suture recurved, markedly arcuate to rear in midline. Clypeus microreticulate. Labroclypeal suture
straight, with well defined lateral angles. Labrum bilobed, constricted at base, microreticulate, each lobe asymmetrical,
side of median emargination straight; median emargination ended slightly above midlength of labrum. Maxillary palpus
with following lengths (mm) of palpomeres 2, 3 and 4, respectively: 0.28/0.10/0.20; palpomere 2 bent outward at
approximately midlength; apices of palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface slightly
arcuate, apex of arc near apical 0.66, median surface evenly arcuate; palpomere 4 widest at approximately midlength.
Mentum wider than long, with large depressions near anterior margin, otherwise microreticulate. Submentum
microreticulate. Genae shining; lateral area of each gena with well developed foveola; posterior margin of each gena with
ridge. Last five antennomeres pubescent. Eyes slightly less than 0.20 interocular distance in width. Thorax: Pronotum
length at midline 0.36 mm; maximum width (before midlength) 0.58 mm; sides not margined, coarsely denticulate; sides
markedly produced at middle, slightly arcuate and convergent to anterior angles, slightly arcuate and markedly convergent
to posterior 0.17, thence parallel to midline to posterior angles; anterior border 0.44 mm wide, nearly straight and nearly
perpendicular to midline in lateral 0.25, moderately arcuate to rear in middle 0.50; posterior border 0.42 mm wide, arcuate
to rear; surface with large, deep punctures and microreticulation, latter quite evident on interstices; many punctures with
short, fine seta; posterointernal foveolae well developed, with punctures less evident than those on callosities; anterointemal
foveolae well developed, with some punctures confluent; anterior and posterior callosities well developed, quite rounded;
median ridge evident for entire length of pronotum; posteroexternal foveolae well developed, confluent with lateral
furrows; anteroexternal foveola well developed, separated from lateral furrow by narrow ridge. Prosternum very slightly
carinate, produced to point between coxae, not produced anteriorly as spine; coxae widely separated. Mesosternum with
internal and external carinae divergent from anterior to posterior; median carina ended near base of intercoxal process;
intercoxal process width at apex subequal to distance between internal and median carinae, with median, longitudinal
ridge. Metasternum with low ridge posterior to intercoxal process; plaques extended from near hind coxae to anterior 0.56
of metasternum, separated by 0.50 length of metasternum; furrow lateral to each plaque. Elytra: Length 1.06 mm.
Maximum width (at midlength) 0.80 mm. Surface dull, disc with 10 rows of deeply impressed punctures between suture
and humeral callus; rows very straight; intervals slightly elevated, width 0.50 puncture diameter, as are interstices between
adjacent punctures of row; intervals and interstices with various reflections, surface uneven; each puncture with short seta
at its anterior side. Explanate margin wide, extended to elytral apices, with denticulations at anterior angles, remainder
with fine serrations. Elytral apices, in posterior aspect, slightly arcuate to ventral surface. Abdomen: Intercoxal segment
transverse, glabrous. Segment 7 without emargination at apex (female). Legs: Metatibiae of males as illustrated
(Figs. 66C,G). Genitalia: Aedeagus as illustrated (Fig. 67A)(5 examined).

Natural History. - Adults are typically found on leaves, twigs and other plant debris
trapped behind stones and boulders in rapid tropical streams (Figs. 196A-C).

Distribution. - (Figs. 68B,174). From the state of Colima, Mexico, south to Honduras.
Remarks. - Only five of the 232 specimens studied (see appendix) were males, suggesting
that perhaps S. brevis is facultatively parthenogenetic.

Western Hemisphere Hydraenidae

221

Figs. 67 A - D, Aedeagi of Spanglerina species. (A) S. brevis , specimen from Oaxaca, Mexico. (B) S. frondsicola ,
holotype. (C) S.fluvieola, holotype. (D) S. ingens , holotype.

4. Spanglerina frondsicola new species
(Figs. 66A-B,67B,68A,174)

Type-locality. - Eleven miles SW Compostela, Nayarit, Mexico.

Type-specimens. - The holotype male and allotype female with identical data are deposited
in USNM. Paratypes from the same locality are deposited in USNM (8) and PDP (15).
Additional paratypes (15 PDP) have the following data: Mexico, Jalisco, 18 mi. S. Puerto
Vallarta. All of the above specimens were collected by my wife Maureen and I during the
month of July, 1974.

Quaest. Ent., 1980, 16 (1,2)

222

Perkins

Diagnosis. - Adults are very similar to those of S. brevis, differing in aedeagal form and
some external features which are discussed in the diagnosis of that species.

Description. — Form: Ovate. Size: Holotype 1.60 mm long, 0.78 mm wide. Color: Head bicolored, frons dark
brown, nearly black, clypeus reddish brown; labrum reddish brown; maxillary palpi light brown; antennae light brown.
Pronotum, elytra and venter reddish brown. Head: Length 0.24 mm. Width 0.40 mm. Frons coarsely punctured, some
punctures confluent, especially near anterior; deep foveola median to each eye, extended to labroclypeal suture.
Frontoclypeal suture recurved, markedly arcuate to rear in midline. Clypeus microreticulate. Labroclypeal suture straight,
with well defined lateral angles. Labrum bilobed, constricted at base, microreticulate, each lobe asymmetrical, sides of
median emargination straight, ended slightly above midlength of labrum. Maxillary palpus with following lengths (mm) of
palpomeres 2, 3 and 4, respectively: 0.28/0.10/0.24; palpomere 2 bent outward at approximately midlength; apices of
palpomeres 2 and 3 not especially expanded; palpomere 4 with lateral surface slightly arcuate, apex of arc near apical 0.66,
median surface evenly arcuate; palpomere 4 widest near midlength. Mentum wider than long, with large depressions near
anterior margin, otherwise microreticulate. Submentum microreticulate. Genae shining; lateral area of each gena with
well developed foveola; posterior margin of each gena with ridge. Last five antennomeres pubescent. Eyes slightly less than
0.20 interocular distance in width. Thorax: Pronotum length at midline 0.36 mm; maximum width (near midlength)

0.58 mm; sides not margined, coarsely denticulate; sides markedly produced at middle, slightly arcuate and convergent to
anterior angles, slightly arcuate and markedly convergent to posterior 0.17, thence parallel to midline to posterior angles;
anterior border 0.44 mm wide, nearly straight and nearly perpendicular to midline in lateral 0.25, moderately arcuate to
rear in middle 0.50; posterior border 0.42 mm wide, arcuate to rear, surface with large, deep punctures and
microreticulation, latter most evident in center of larger punctures; many punctures with short, fine seta, interstices on
callosities thin ridges without microreticulation; posterointernal foveolae well developed, without large punctures, but
microreticulation very evident; anterointernal foveolae well developed, with some punctures confluent; anterior and
posterior callosities well developed, rounded; median ridge evident for entire length of pronotum; posteroexternal foveola
well developed, confluent with lateral furrow; anteroexternal foveolae well developed, separated from lateral furrow by a
narrow ridge. Prosternum very slightly carinate, produced to point between coxae, not produced anteriorly as spine; coxae
widely separated. Mesosternum with internal and external carinae divergent from anterior to posterior; median carina
ended near base of intercoxal process; width of intercoxal process at apex subequal to distance between internal and
median carinae, with median, longitudinal ridge. Metasternum with low elevation posterior to intercoxal process; plaques
reduced to very short, somewhat peaked carinae in midlength of metasternum, separated by 0.50 length of metasternum;
furrow lateral to each plaque. Elytra: Length 1.06 mm. Maximum width (at midlength) 0.78 mm. Surface dull, disc with
10 rows of deeply impressed punctures between suture and humeral callus, rows very straight; intervals slightly elevated,
width 0.50 puncture diameter, as are interstices between adjacent punctures of a row; intervals and interstices with various
reflections, surface uneven; each puncture with short seta at its anterior side. Explanate margin wide, extended to elytral
apices, with denticulations at anterior angles, remainder with fine serrations. Elytral apices, in posterior aspect, slightly
arcuate to ventral surface. Abdomen: Intercoxal segment transverse, glabrous. Segment 7 with emargination at apex
(male). Legs: Protibia expanded near apex. Metatibia with brush of hairs near apex (male). Genitalia: Aedeagus as
illustrated (Fig. 67B)(7 examined).

Natural History. - Most of the specimens from the type-locality were removed from
water-soaked leaves of Cecropia trees. These leaves had become trapped behind rocks in a I!
moderately swift tropical stream.

Distribution. - (Figs. 68A,174). Presently known from the states of Nayarit and Jalisco,
Mexico.

Etymology. - Latin, frondis (foliage) plus icola (dweller). This epithet refers to the
microhabitat of S.frondsicola.

GENUS LIMNEBIUS LEACH

Limnebius Leach, 1815 (type-species: Hydrophilus nitidus Marsham). - Casey, 1900:51-53. - d’Orchymont, 1932b:
657-665. - Brown, 1932:5-6. - d’Orchymont, 1938b:275-291. - d’Orchymont, 1945b: 1-24. - Leech and Chandler,
1956:332. -J. Balfour-Browne, 1956:103-107. - F. Balfour-Browne, 1958:131-142.

Limnocharis Horn, 1 872 (type-species: Limnocharis piceus Horn). - Horn, 1872:1 44- 1 45. - Casey, 1 886: 1 67- 171.

Discussion. - Adults of Limnebius are distinctive within the Hydraenidae, the body form

(Fig. 69 A) with its more-or-less evenly arcuate sides and lack of pronotal foveae resulting in a
facies quite different from adults of other genera. The facies, in fact, is more similar to that of
hydroscaphids, certain ptiliids, primitive staphylinids and phalacrids than to the remainder of

Western Hemisphere Hydraenidae

223

the hydraenids, an interesting example of convergence.

Limnebius lacks the morphological diversity of Ochthebius and Hydraena, contains fewer
species, and is less widely distributed. However, the number of species placed in Limnebius ,
about 100 worldwide, far surpasses the other, much smaller genera.

The genus is primarily north temperate in distribution, but has some tropical elements.
Apparently it is absent from Australia and New Zealand. In the Western Hemisphere it is
restricted to North America (including Mexico) and Guatemala, being absent from the
remainder of Central America, the Antilles and South America (Fig. 160).

Differences between species of Limnebius are generally very subtle, most species reliably
differentiated only by referral to the aedeagus. Slight microsculpture differences, such as
degree of impression of microreticulation, are often more confusing than helpful, as I have
found that they vary considerably within species (see L. alutaceus ).

J. Balfour-Browne (1956), in a paper on Indian Limnebius , expressed the external sameness
of the species: “Verbal descriptions, though of little practical use in identifying the species, are
appended for most of the species. Dissection and examination of the genitalia is essential for
recognition of the species.”. I have found this to be true for Western Hemisphere species also,
and the brevity of my descriptions reflects the external sameness of the species.

Two subgenera are currently recognized for the genus, Limnebius ( sensu stricto) and L.
(Bilimneus), which were redefined by d’Orchymont (1938b) on the basis of presence (sensu
stricto) or lack {Bilimneus) of parameres. Using this criterion, all of the species in the Western
Hemisphere are placed in Limnebius {sensu stricto) since males have at least some setae on
what must be considered modified parameres (Figs. 70,71).

All males have two setae on the “main-piece” of the aedeagus, and there are other setal
homologies (cf. Figs. 70,71) which suggest a close relationship between all of the Western
Hemisphere species. However, close study of males of non-Western Hemisphere species is
necessary to demonstrate that these structures are not widely distributed in the genus.

Two types of aedeagi are represented in the New World fauna, one in which the apical lobe
(main-piece) is mobile and more-or-less articulates with the basal portion (Fig. 73C), and one
in which these two parts have apparently fused as a single piece (Fig. 73A)(see section on
phylogeny for additional comments). Unfortunately, however, external characteristics
corresponding to these two aedeagal types are not apparent. Consequently, I have elected not to
group the species into morphological aggregates, but to arbitrarily join them into geographical
groups in hope of simplifying the task of identification, which should be based upon the
aedeagal forms.

The base of the aedeagus is either globose (Fig. 77B) or ovate (Fig. 77A), and in both types
it contains a coiled tube (Figs. 70,71). Of the more than 1,000 aedeagi of various species of
Limnebius that I have studied, a single example of L. ozapalachicus has the coiled tube
extended (Fig. 75D), and I suspect that most species have the ability to extend this tube during
copulation. The rareness of the extended condition in preserved specimens may relate to
contraction caused by alcohol in which the beetles are preserved, as I have remarked also
concerning the aedeagal tube in Gymnochthebius. (Anyway, one would not expect to find the
copulatory position in specimens which were preserved during non-copulatory activity). The
long duct connecting the spermatheca and bursa copulatrix of Limnebius (Fig. 10K) also
suggests that this coiled tube is extended during copulation.

Diagnosis. - Easily distinguished from adults of other genera by the evenly arcuate sides of
the body (Fig. 69A), lack of pronotal foveae, lack of elytral striae or rows of punctures, and

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Perkins

Figs. 68A - B, Geographical distribution of Spanglerina species. (A) S.fluvicola • , S.frondsicola ★ and S', ingens A .
(B) S. brevis.

proportions of maxillary palpal segments, with palpomeres 2 and 3 subequal in length
(Fig. 148D).

Description. — Form: Elongate-oval, moderately convex. Size: Length 1.15-1.70 mm, width 0.55-0.85 mm. Most
females larger than males. Color: Most species black, a few dark brown. Head: Very finely punctate to alutaceous, very
sparsely pubescent. Eyes with antero-dorsal facets effaced. Interocular tuberculi and foveae absent. Labrum shallowly

Western Hemisphere Hydraenidae

225

emarginate, not upturned in either sex. Maxillary palpus moderately long, palpomeres 2 to 4 with approximate ratio of
6:7:8. Antennomeres nine (4+5). Thorax: Pronotum with sides arcuate, width at anterior slightly less than that at
posterior; foveae absent. Prosternum with coxal cavities open behind. Metasternum pubescent except for small
postero-median region. Elytra: Finely punctate to alutaceous, striae and serial rows of punctures absent. Males with
apices generally more truncate than females. Abdomen: Basal five sterna hydrofuge pubescent, last two segments
sparsely pubescent, with stout spines laterally. Legs: Of moderate length, pro- and mesotarsi with large suction setae in
males. Genitalia: Aedeagus of many males with setae near midlength, but without distinct parameres; base oval,

containing coiled duct.

Key to Western Hemisphere species of Limnebius

1 ( 0 ) Specimens from the eastern United States west to and including the Ozark

Plateau 3

V Specimens from western North America or Central America 2

2 ( 1') Specimens from the western United States, Baja California, and British

Columbia 5

2' Specimens from Arizona, New Mexico and Texas south to Guatemala 15

3 ( 1 ) Males with median depression on abdominal sternum 6. Females with sides of

elytra gradually arcuate near apices 4

V Males without median depression on abdominal sternum 6. Females with sides

of elytra straight near apices; aedeagus as illustrated (Fig. 73D);

L. discolor Casey, p. 227

4 ( 3 ) Aedeagus as illustrated (Fig. 72A) L. richmondi, new species, p. 227

4' Aedeagus as illustrated (Fig. 75 A-D)

L. ozapalachicus , new species, p. 230

5 (2) Males 6

5' Females 1 1

6 ( 5 ) Abdominal sternum 6 without median oval depression 7

6' Abdominal sternum 6 with median oval depression 8

7 ( 6 ) Width of head at eyes approximately equal that of anterior area of pronotum,

together they form arcuate sides; microreticulation of dorsum less apparent;

aedeagus as illustrated (Fig. 72D); California L. leechi, new species, p. 235

7' Head narrower than anterior area of pronotum, together they form slightly
emarginate sides; microreticulation more apparent; aedeagus as illustrated
(Fig. 73B); Utah L. utahensis, new species, p. 236

8 ( 6') Abdominal sternum 6 with tuft of hairs at posterior margin of median oval

depression; microreticulation of dorsum generally more apparent; aedeagus as
illustrated (Figs. 79A-B); southern British Columbia and Montana to southern

California L. alutaceus (Casey), p. 230

8' Abdominal sternum 6 without tuft of hairs at posterior margin of median oval

depression; microreticulation of dorsum generally less apparent 9

9 ( 8') Elytra brown, legs orange-brown, contrasted with much darker venter; aedeagus

as illustrated (Fig. 77B); southern British Columbia to Montana

L. borealis , new species, p. 235

9' Elytra black, legs dark brown, not distinctively contrasting with venter; Oregon

to Baja California 10

10 (9') Sides of elytra more markedly convergent to posterior, width at posterior less;

microreticulation less developed, dorsum more reflective; aedeagus as illustrated

(Fig. 75F); northern California to Baja California

L. piceus (Horn), p. 230

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Perkins

10' Sides of elytra less convergent to posterior, width at posterior greater;

microreticulation more developed, dorsum less reflective; aedeagus as illustrated

(Figs. 70,73C); northern Oregon to Baja California

L. arenicolus, new species, p. 234

11 (5') Elytral apices incised at suture, apices more prominent, each elytron with

greatest length slightly before suture 12

11' Elytral apices not deeply incised at suture, together in form of more or less

rounded apex 13

12 (11) Elytra wider at posterior, sides slightly angulate near posterior 0.20;

microreticulation more apparent, dorsum less reflective; northern Oregon to

Baja California L. arenicolus , new species, p. 234

12' Elytra narrower at posterior, sides lacking angulation at posterior 0.20;

microreticulation less apparent, dorsum more reflective; northern California to
Baja California L. piceus (Horn), p. 230

13 (IE) Elytra brown, legs orange-brown, contrasted with dark venter; southern British

Columbia to Montana L. borealis , new species, p. 235

13' Elytra black, legs dark brown, not distinctively contrasted with venter 14

14 (13') Width of head at eyes approximately equal that of anterior area of pronotum,

together they form arcuate sides; center of pronotal disc non-microreticulate . .

L. leechi, new species, p. 235

14' Head narrower than anterior area of pronotum, together they form slightly

emarginate sides; center of pronotal disc microreticulate

L. alutaceus (Casey), p. 230

15 (20 Abdominal sternum 6 of males with median oval depression; elytra of females

not sinuate before apex 16

15' Abdominal sternum 6 of males without median oval depression; elytra of

females sinuate before apex or not 18

16 (15 ) Aedeagus as illustrated (Fig. 77D); females with elytra straight slightly before

apex; Oaxaca, Mexico L. mexicanus, new species, p. 243

16' Aedeagus not as above; females with elytra gradually arcuate to apices 17

17 (160 Aedeagus as illustrated (Fig. 75E); Texas L. texanus, new species, p. 241

17' Aedeagus as illustrated (Fig. 77C); Guatemala

L. octolaevis, new species, p. 243

18 (150 Aedeagus as illustrated (Fig. 73A); females with elytra sinuate before apex

(Fig. 69F); Colorado to Guatemala L. sinuatus (Sharp), p. 236

18' Aedeagus not as above; females with elytra not sinuate before apex 19

19 (180 Aedeagus as illustrated (Fig. 77 A); New Mexico

L. aridus, new species, p. 241

19' Aedeagus not as above 20

20 (190 Aedeagus as illustrated (Fig. 72C); females with elytra straight slightly before

apex; Zacatecas and Nayarit, Mexico L. mitus, new species, p. 238

20" Aedeagus as illustrated (Fig. 72B); females with elytra gradually arcuate to

apices; Texas to Tamaulipas, Mexico L. angustulus (Casey), p. 238

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227

1. Limnebius discolor Casey
(Figs. 73D,78B,175)

Limnebius discolor Casey, 1900:52 (lectotype female deposited in USNM, here designated; type-locality: Bennington

County, Vermont, U.S.A).

Diagnosis. - Aedeagal form (Fig. 73D) and brownish elytra are the distinctive features of L.
discolor adults.

Description. — Form: Broadest at posterior angles of pronotum; slightly parallel sided. Size: Holotype 1.24 mm
long, 0.60 mm wide. Color: Head black; pronotum brownish at margins, remainder black; elytra and legs brown. Head:
Finely punctulate, finely microreticulate. Pronotum : Finely punctulate; microreticulation of lateral areas as apparent as
that on head, slightly reduced on disc. Elytra: microreticulation more apparent than that on head. Apices moderately
truncate. Abdomen: Sternum 6 with very shallow, oval median impression. Genitalia: Male (Fig. 73D)( 1 0 1 examined).

Variation. - Females have the elytral apices acute, the sides just before the apex being
rather distinctively straight.

Natural History. - A long series of Limnebius was collected from the margins of a small
stream in Virginia (Fig. 193B). The substratum consisted primarily of flat slate fragments that
were quite small and well worn. I dissected all 106 males from that collection, and found 92 L.
discolor , 11 L. ozapalachicus and 2 L. richmondi. This illustrates a phenomenon not
infrequently witnessed in this family, that is, extremely low population densities of some species
within a sample containing a much more abundant species.

Distribution. - (Figs. 78B,175). Presently known from Missouri, Indiana, Maryland,
Virginia, Pennsylvania and Vermont.

Remarks. - Refer to the appendix for detailed locality data. A total of 216 specimens was
studied.

2. Limnebius richmondi new species
(Figs. 72A,78B,175)

Type-locality. - Roaring Brook, Lowville, Lewis County, New York, U.S.A.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. H. Notman collected these specimens on June 21, 1921. Paratypes consist of two
males (PDP) with the following data: 12 mi. S. Williamsville, pebbly stream, Bath County,
Virginia, 6-X-73, P.D. Perkins.

Diagnosis. - Aedeagal form (Fig. 72A), presence of a median depression on the abdominal
sternum 6 in males, and brownish elytra in both sexes are distinctive features.

Description. — Form: Broadest near posterior angles of pronotum, sides of elytra straight. Size: Holotype 1.36 mm
long, 0.64 mm wide. Color: Head, pronotum and venter black-brown; elytra dark brown; legs brown. Head: Finely
punctulate, finely microreticulate. Pronotum : Finely punctulate, microreticulation as on head laterally, reduced on disc.
Elytra: Finely punctulate, microreticulation more apparent than that of head; apices truncate. Metasternum : Small area
in front of hind coxae non-pubescent. Abdomen: Sternum 6 with median depression. Genitalia: Male (Fig. 72A)(3
examined).

Variation. - Females have the elytral apices arcuate laterally.

Distribution. - (Figs. 78B,175). Appalachian Mountains from Virginia to New York.

Etymology. - I am pleased to dedicate this new species to the late E.A. Richmond, in
recognition of his contributions to knowledge of hydraenid and hydrophilid larvae.

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Perkins

Figs. 69A - H, Limnebius sinuatus and L. alutaceus. (A) L. sinuatus, $ dorsal habitus (arrows indicate pronotal sensilla).
(B) L. sinuatus , 3 ventral habitus. (C) L. sinuatus , protarsal suction setae. (D) L. alutaceus , microsculpture of elytral disc.
(E) L. sinuatus, microsculpture of pronotum. (F) L. sinuatus, 2 elytral apices. (G) L. alutaceus, 2 elytral apices. (FI) L.
sinuatus, right eye and antenna.

Western Hemisphere Hydraenidae

229

Figs. 70A - B, Aedeagus of Limnebius arenicolus, microslide mount. (A) dorsal aspect. (B) ventral aspect.

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Perkins

3. Limnebius ozapalachicus new species
(Figs. 75A-D/78B, 175, 193B)

Type-locality. - 12 mi. S. Williamsville, Bath County, Virginia, U.S.A.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. I collected these specimens October 6, 1973. Paratypes (300) are listed in the
appendix.

Diagnosis. - Aedeagal form (Figs. 75A-D), lack of a median depression on sternum 6 in
males, brownish legs and elytra in both sexes, and geographical distribution are distinctive
aspects.

Description. — Form: Broadest near posterior angles of pronotum, elytra rather straight sided. Size: Holotype
1.30 mm long, 0.64 mm wide. Color: Head, pronotum and venter black-brown, legs and elytra brown. Head: Finely
punctulate, finely microreticulate. Pronotum-. Finely punctulate, microreticulation in lateral areas as on head, reduced on
disc. Elytra: Finely punctulate, microreticulation more apparent than that of head; apices feebly truncate. Metasternum :
Small non-pubescent area in front of hind coxae. Abdomen: Sternum 6 without median depression. Genitalia: Male
(Figs. 75A-D)(131 examined).

Variation. - Females have the elytral apices arcuate. The apex of the aedeagus
(Figs. 75A-D) is increased in width eastward from the Ozark Plateau and northward in the
Appalachian Mountains. The left side (in a morphological sense) tends to become slightly more
angulate in the same northward direction, a trend similar to that occurring in the western
species, L. alutaceus.

Natural History. - Refer to the natural history section of L. discolor for comments.

Distribution. - (Figs. 78B,175). Ozark Plateau and Appalachian Mountains of the eastern
U.S.A.

Etymology. - Latin adjective, ozapalachicus , in reference to the geographical distribution.

4. Limnebius piceus (Horn)

(Figs. 75F,76D,175)

Limnocharis piceus Horn, 1872:144 (holotype female deposited in MCZ; type-locality: Fort Crook, California, U.S.A.).

Casey, 1886:168. - Casey, 1900:52. - D’Orchymont, 1945:14. - Leech and Chandler, 1956:332.

Limnocharis polita Casey, 1886:168 (lectotype female deposited in USNM, here designated; type-locality: San Francisco,

California). - Casey, 1900:52.

Diagnosis. - Aedeagal form (Fig. 75F), presence of a median depression on abdominal
sternum 6 of males, and dehiscent elytral apices of females are distinctive characteristics.

Description. — Form: Broadest at posterior angles of pronotum, sides feebly arcuate. Size: Males about 1 .28 mm
long, 0.72 mm wide. Color: Black. Head: Finely punctulate, finely microreticulate. Pronotum : Finely punctulate, finely
microreticulate laterally, less so on shiny disc. Elytra: Finely punctulate, microreticulation slightly more pronounced than
that of head; apices truncate. Metasternum: Small area in front of hind coxae non-pubescent. Abdomen: Sternum 6 with
well developed median depression. Genitalia: Male (Fig. 75F)(105 examined).

Variation. - Females have the elytra angularly incised at the suture, hence each elytron is
longest some distance before the suture.

Distribution. - (Figs. 76D,175). From northern California to northern Baja California.

Remarks. - Detailed locality data are given in the appendix; 257 specimens were examined.

5. Limnebius alutaceus (Casey)

(Figs. 69D,G,71,76A,79A-B,175)

Limnocharis alutacea Casey, 1886:169 (holotype female deposited in USNM; type-locality: Mendocino County,

California). - Casey, 1900:52. - D’Orchymont, 1945:16. - Leech and Chandler, 1956:332.

Western Hemisphere Hydraenidae

231

Figs. 71 A - B, Aedeagus of Limnebius alutaceus , microslide mount. (A) dorsal aspect. (B) ventral aspect.

Figs. 72A - D, Aedeagi of Limnebius species. (A) L. richmondi, holotype. (B) L. angustulus , specimen from Tamaulipas,
Mexico. (C) L. mitus, holotype. (D) L. leechi, holotype.

I

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Perkins

Limnocharis congener Casey, 1886:170 (lectotype female deposited in USNM, here designated; type-locality: Mendocino

County, California; new synonomy). - Casey, 1900:52.

Limnebius columbianus Brown, 1932:5 (holotype male deposited in CNC; type-locality: Similkameen River, Copper Mt.,

British Columbia, Canada; new synonomy).

Casey’s type-specimen of congener and Brown’s type-specimen do not differ significantly
from Casey’s alutaceus type-specimen. I have illustrated the aedeagus of Brown’s
type-specimen (Fig. 79B). Refer to the section on variation for additional comments.

Diagnosis. - Aedeagal form (Figs. 71,79A-B), presence of a median depression on
abdominal sternum 6 in males, and well developed anterior pronotal angles in both sexes are
distinctive features.

Description. — Form: Broadest at posterior angles of pronotum; sides of head forming an angle with pronotum.
Size: Males about 1.60 mm long, 0.80 mm wide. Color: Black. Head: Finely punctulate, moderately microreticulate.
Pronotum: Finely punctulate, moderately to markedly microreticulate laterally, moderately microreticulate on disc.
Elytra: Finely punctulate, microreticulation similar to that of pronotal lateral areas. Metasternum: Small pubescent area
in front of hind coxae. Abdomen: Sternum 6 with large median depression. Genitalia: Male (Figs. 71,79A-B)(202
examined).

Variation. - Specimens are larger on average and more markedly microreticulate
northward. Some specimens from the southern extreme of the range have lightly impressed
pronotal microreticulation, hence the disc is shiny. By contrast, northern specimens, such as the
type-series of L. columbianus Brown, have the pronotal disc markedly microreticulate and dull.
There is a corresponding difference in the aedeagi from the two areas (Figs. 79A-B). Northern
males have the left side (in a morphological sense) decidedly more angulate than southern
specimens. Geographically speaking, the two aedeagal forms are most narrowly separated in
Idaho (Fig. 76A), where one locality each is known from the counties of Blaine and Lemhi.
Only a single male is known from each of these localities, which are about 100 miles apart. The
aedeagus of the male from the southernmost of these two localities (Blaine) is clearly of the
southern form, whereas the northernmost is clearly of the northern aedeagal form. Since
neither of these forms represents an intermediate stage, this might be considered evidence to
support a two species hypothesis. However, based upon the morphological gap separating the
aedeagi of other species, plus the variation seen within certain species, such as the eastern L.
ozapalachicus, I am treating these two forms as conspecific. Should future collecting reveal
specimens of both aedeagal forms cohabiting, then this position will need to be reversed and L.
columbianus Brown reinstated. Also, if future collecting in Oregon, Washington and Idaho
should demonstrate that the two forms are truly allopatric, then the problem will need
reanalysis.

Natural History. - Elsewhere (Perkins, 1976), I have presented some details of
microhabitat preferences of L. alutaceus in southern California (under the name Limnebius
Sp. A).

Distribution. - (Figs. 76A,175). Southern British Columbia to southern California.

Remarks. - All of the syntypes of this species in the Casey Collection at the USNM are
females. All of the specimens he had identified as L. piceus Horn are males of L. alutaceus ,
except one, a male of L. arenicolus. He apparently thought that differences in shape of the
elytral apices in the two sexes were of a species specific nature. Detailed locality data are given
in the appendix; 434 specimens were examined.

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233

Figs. 73A - D, Aedeagi of Limnebius species. (A) L. sinuatus, specimen from Coconino County, Arizona. (B) L.
utahensis , holotype. (C) L. arenicolus, holotype. (D) L. discolor , specimen from Bath County, Virginia.

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6. Limnebius arenicolus new species
(Figs. 70,73C,76C,175)

Type-locality. - San Gabriel River, West Fork Station, 3100 feet, Los Angeles County,
California, U.S.A.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. I collected these specimens, November 15, 1971. Paratypes (472) are listed in the
appendix.

Fig. 74. Geographical distributions of Limnebius sinuatus • , L. mitus ★ , L. mexieanus A and L. oetolaevis H

Diagnosis. - Aedeagal form (Figs. 70,73C) and presence of a median depression on
abdominal sternum 6 in males are distinctive features.

Description. — Form: Broadest near anterior angles of pronotum, sides of elytra slightly arcuate. Size: Holotype
1.40 mm long, 0.72 mm wide. Color: Black. Head: Finely punctulate, finely microreticulate. Pronotum-. Finely punctulate,
microreticulation laterally as on head, slightly reduced on disc. Elytra: Finely punctulate, microreticulation slightly more
apparent than that of head. Metasternum : Small non-pubescent area in front of hind coxae. Abdomen: Sternum 6 with
median depression. Genitalia: Male (Figs. 70,73C)(261 examined).

Variation. - Females have the elytral apices arcuate laterally.

Natural History. - For some details of the microhabitat preferences of L. arenicolus , refer
to Perkins (1976), where it is discussed under the name Limnebius Sp. B.

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235

Distribution. - (Figs. 76C,175). From northern Oregon to northern Baja California.
Etymology. - Latin, arena (sand) plus colus (dweller). I refer to the microhabitat of this
species.

7. Limnebius leechi new species
(Figs. 72D,76B, 175)

Type-locality. - McDowell Creek just below Oasis, 1800 feet, Mendocino County,
California, U.S.A.

Type-specimens. - The holotype male and allotype with identical data are deposited in
CAS. These specimens were collected by Hugh B. Leech, July 27, 1955. Paratypes (54) are
listed in the appendix.

Diagnosis. - Aedeagal form (Fig. 72D) and lack of a median depression of abdominal
sternum 6 in males are the reliable recognition characteristics of L. leechi.

Description. — Form: Broadest near anterior angles of elytra; sides feebly arcuate. Size: Holotype 1.48 mm long,
0.72 mm wide. Color: Black Head: Finely punctulate, finely microreticulate. Pronotum : Finely punctulate, microreticulate
laterally as on head, reduced on disc; pubescence evident. Elytra: Finely punctulate, slightly more markedly
microreticulate than head; apices truncate. Abdomen: Sternum 6 longer than 5, without median depression. Genitalia:
Male (Fig. 72D)(33 Examined).

Variation. - Females have the elytral apices feebly arcuate.

Natural History. - Habitat descriptors include “seepage trickle over gravelly soil” and
“pools in drying bed of Upper Mad River”. Of the 17 localities known to date, most are
represented by four or fewer specimens, the maximum being 10 specimens. Whether this is an
artifact of collecting technique or actually reflects very low population density remains to be
clarified.

Distribution. - (Figs. 76B,175). California, principally in the coastal mountain ranges.

Etymology. - I am pleased to dedicate this species to Hugh. B. Leech in recognition of the
many specimens which have been available to this study due to his excellent field work.

Remarks. - D’Orchymont (1945b) mistakenly illustrated the aedeagus of this species under
the name Limnebius congener (Casey). D’Orchymont had not seen the type-specimens of L.
congener , which name is here synonomized with Limnebius alutaceus (Casey).

8. Limnebius borealis new species
(Figs. 76B,77B,175)

Type-locality. - Shuswap River, Enderby, British Columbia, Canada.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. Hugh B. Leech collected these specimens, October 1 1, 1946. Paratypes (37) are listed
in the appendix.

Diagnosis. - Aedeagal form (Fig. 77B), brown elytra, and presence of a median depression
on abdominal sternum 6 in males are distinctive characteristics.

Description. — Form: Broadest near anterior angles of pronotum, sides of elytra slightly arcuate. Size: Holotype
1.40 mm long, 0.78 mm wide. Color: Dorsum and venter dark brown; legs, palpi and elytral epipleura light brown. Head:
Finely punctulate, microreticulate. Pronotum: Finely punctulate, microreticulate. Elytra: Finely punctulate,

microreticulate; apices truncate. Metasternum\ Small non-pubescent area in front of hind coxae. Abdomen: Sternum 6
with a median depression. Genitalia: Male (Fig. 77B)(25 examined).

Variation. - Females have the elytral apices arcuate laterally.

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Distribution. - (Figs. 76B,175). Presently known from British Columbia and Montana.
Etymology. - Latin, borealis (northern). I refer to the geographical distribution of this
species.

9. Limnebius utahensis new species
(Figs. 73B,76B, 175)

Type-locality. - Wasatch Mountains, Utah, U.S.A.

Type-specimen. - The holotype male (unique) is deposited in CAS. This specimen was
collected by O. Bryant, June 28, 1947.

Diagnosis. - Aedeagal form (Fig. 73B), absence of median depression on abdominal
sternum 6 in males, quite uniform microreticulation over the entire dorsum, and geographical
distribution are distinctive features.

Description. — Form: Broadest near anterior angles of elytra, sides of elytra very slightly arcuate. Size: Holotype
1.44 mm long, 0.66 mm wide. Color: Dorsum and venter black; legs and palpi brown. Head: Finely punctulate, moderately
microreticulate. Pronotum: Finely punctulate, moderately microreticulate. Elytra: Finely punctulate, moderately
microreticulate; apices truncate. Metasternum : Small non-pubescent area in front of hind coxae. Abdomen: Sternum 6
without median depression. Genitalia: Male (Fig. 73B)(1 examined).

Distribution. - (Figs. 76B,175). Known only from the type-locality in the Wasatch
Mountains of Utah.

Etymology. - Latinized adjective, utahensis , in reference to geographical distribution.

Remarks. - The holotype has two small but very apparent foveolae on the pronotal disc, one
on each side of the midline slightly behind the middle. These foveolae are slightly larger than
the marginal foveolae in front of the scutellum. Additional specimens are necessary to confirm
the constancy of this characteristic.

10. Limnebius sinuatus (Sharp)

(Figs. 3C, 1 OK, 1 1 B,69 A-C,E-F,H,73 A,74, 1 48D, 1 49D, 1 50A-C, 1 52C-D, 1 53F-G, 1 75)

Limnocharis sinuatus Sharp, 1882:86 (holotype female deposited in BMNH; type-locality: San Joaquin, Baja Vera Paz,

Guatemala).

Diagnosis. - Aedeagal from (Fig. 73 A), absence of a median depression on abdominal
sternum 6 in males, sinuate elytral apices in females (Fig. 69F), and a small non-pubescent
area on metasternum just in front of hind coxae in both sexes serve as diagnostic characteristics
for L. sinuatus.

Description. — Form: Broadest near anterior angles of elytra; sides feebly arcuate. Size: Males about 1.16 mm
long, 0.60 mm wide. Color: Black. Head: Finely punctulate, finely microreticulate. Pronotum: Finely punctulate, finely
microreticulate laterally, disc non-micoreticulate, shiny. Elytra: Finely punctulate, microreticulation more apparent than
that of head; apices moderately truncate. Metasternum : Glabrous in very small area just anterior to hind coxae. Abdomen:
Sternum 6 without definite median depression. Genitalia: Male (Fig. 73 A)( 1 43 examined).

Variation. - Females of this species are unique in having the elytral apices distinctively
sinuate just before the apex (Fig. 69F). There is some very slight, non-significant variation in
contours of the aedeagal apex; it does not warrant illustration.

Natural History. - This species is relatively common in Guatemala and Mexico, frequently
becoming very abundant locally (see appendix). Highest population densities are reached in
streams of open habitats, such as pine-oak woodland, but specimens are also found at margins
of streams in more arid regions (Fig. 195A). Despite intensive collecting on seepage areas at
many localities throughout Guatemala and Mexico (principally in densely vegetated, tropical
habitats), I was unable to find a single specimen of L. sinuatus. Some of these madicolous

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Figs. 75A - F, Aedeagi of Limnebius species. (A) L. ozapalachicus , holotype. (B) L. ozapalachicus , variant from Maine.
(C) L. ozapalachicus , deformed. (D) L. ozapalachicus , specimen from Ohio County, Kentucky with internal tube
protruded. (E) L. texanus , holotype. (F) L.piceus, specimen from Monterey County, California.

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(seepage) habitats were a short distance from a sandy stream where L. sinuatus adults were
found. Perhaps this is a reflection of the strict psammophilous nature of L. sinuatus. Further
research is needed to verify or reject this suggestion.

Distribution. - (Figs. 74,175). Colorado to Guatemala.

Remarks. - Refer to the appendix for detailed locality data; 623 specimens were examined.

1 1. Limnebius angustulus (Casey)

(Figs. 72B/78A, 175)

Limnocharis angustula Casey, 1 886: 1 68 (holotype female deposited in USN M; type-locality: Austin, Texas, U.S.A.).
Limnocharis coniciventris Casey, 1886:171 (holotype male deposited in USNM; type-locality: Austin, Texas, U.S.A.; new

synonomy).

These type-specimens represent the sexes of one species. Casey apparently overlooked the
obvious pro- and mesotarsal suction setae of the males in this genus. His name coniciventris is a
misnomer; the conical shape of the abdomen and very convex elytra are clearly a result of
shrinkage, as this specimen is quite teneral. Fully hardened and darkened males have the
abdomen shaped as in other species of the genus.

Diagnosis. - Aedeagal form (Fig. 72B), small size and geographical distribution are the
distinctive features of this species.

Description. — Form: Broadest at posterior angles of pronotum; relatively narrow. Size: Males about 1 .20 mm long,
0.12 mm wide. Color: Black. Head: Finely punctulate, finely microreticulate. Pronotum: Finely punctulate, very finely
microreticulate laterally, disc very shiny, not microreticulate. Elytra: Finely punctulate, microreticulation very fine, but
more apparent than that on head and pronotum; sides straight, posterior angles well formed, hence apices truncate.
Abdomen: Sternum 6 without median impression. Genitalia: Male (Fig. 72B)(4 examined).

Variation. - Females have the elytra slightly arcuate at rear.

Natural History. - Three males and two females were collected at the margin of a desert
stream 2 mi. SW Ciudad Victoria, Tamaulipas, Mexico by my wife Maureen and I, July 27,
1974, at the uppermost reaches of the stream, where the ground water was emerging from the
otherwise dry streambed. These specimens plus Casey’s two type-specimens are the only known
to date.

Distribution. - (Figs. 78A,175). Texas and northeastern Mexico.

Remarks. - The aedeagus illustrated is from a specimen collected at 2 mi. SW Ciudad
Victoria. It is virtually identical to that of Casey’s coniciventris type-specimen; the latter,
however, is slightly collapsed due to its teneral condition.

12. Limnebius mitus new species
(Figs. 72C,74,175)

Type-locality. - 13 mi. S. Jalpa, Zacatecas, Mexico.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. Paratypes from the same locality (9 males, 6 females) and 1 1 mi. SW Compostela,
Nayarit, Mexico (1 male, 4 females) are in PDP. These specimens were collected by my wife
Maureen and I, July, 1974.

Diagnosis. - Aedeagal form (Fig. 72C), small size and geographical distribution are the
distinctive features of L. mitus.

Description. — Form: Broadest at posterior angles of pronotum; elytra rather narrow at rear. Size: Holotype
1.16 mm long, 0.58 mm wide. Color: Black. Head: Finely punctulate, microreticulation of clypeus slightly more apparent
than that of frons. Pronotum: Finely punctulate, microreticulation extremely fine, nearly imperceptible on disc. Elytra:
microreticulation more apparent than that of pronotum and head. Posterior marginal angles rounded, hence apices not

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Figs. 76A - D, Geographical distributions of Limnebius species. (A) L. alutaceus. (B) L. leechi • , L. utahensis ★ and
L. borealis A • (C) L. arenicolus. (D) L. piceus.

Quaest. Ent., 1980, 16 (1,2)

Figs. 77 A - D, Aedeagi of Limnebius holotypes. (A) L. aridus. (B) L. borealis. (C) L. octolaevis. (D) L. mexicanus.

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distinctively truncate. Abdomen: Sternum 6 without median oval impression. Genitalia: Male (Fig. 72C)( 1 1 examined).

Natural History. - The holotype and topotypes were collected at the margins of a stream in
an open, arid habitat. By contrast, the five specimens from Nayarit were taken at the edge of a
tropical stream surrounded by dense vegetation. Despite specific collecting efforts in many such
tropical streams in Mexico and Central America, this is the only instance where I found
specimens of this genus in streams of this type.

Distribution. - (Figs. 74,175). Presently known from the states of Zacatecas and Nayarit,
Mexico.

Etymology. - Latin, mitus (mitten). This name refers to the mitten-like shape of the
aedeagus.

13. Limnebius texanus new species

(Figs. 75E,78A,175)

Type-locality. - 2.5 mi. E. of Nickel Creek Station, Culberson County, Texas, U.S.A.

Type-specimens. - The holotype male and allotype with identical data are deposited in
CFMNH. These specimens and six paratypes (2 CFMNH; 2 USNM; 2 PDP) with same data
were collected by B. Malkin, September 2, 1952. Five additional paratypes, with the following
data, are deposited in CFMNH: Texas, Jeff Davis Co., Limpia Creek Canyon, Davis Mts.,
September 5, 1952, B. Malkin.

Diagnosis. - Aedeagal form (Fig. 75E), median depression on the abdominal sternum 6 in
males, and a small non-pubescent area in the middle of the metasternum in both sexes are the
distinctive features of L. texanus.

Description. — Form: Broadest near anterior angles of pronotum, sides feebly arcuate. Size: Holotype 1 .48 mm
long, 0.68 mm wide. Color: Black. Head: Faintly punctulate, faintly microreticulate. Pronotum: Faintly punctulate, faintly
microreticulate, especially on shiny disc. Elytra: Faintly punctulate, microreticulation more apparent than that of head;
apices truncate. Metasternum: Non-pubescent area in midline about as wide as mesosternal process. Abdomen: Sternum 6
with median oval depression. Genitalia: Male (Fig. 75E)(4 examined).

Variation. - Females have the elytral apices feebly arcuate, and have the non-pubescent
area of the metasternum smaller than males.

Distribution. - (Figs. 78A,175). Currently known only from Texas.

Etymology. - Latin adjective, texanus , in reference to the geographical distribution.

14. Limnebius aridus new species

(Figs. 77A,78A,175)

Type-locality. - Double Adobe Ranch, Animas Mts., 5500 feet, Hidalgo County, New
Mexico, U.S.A.

Type-specimen. - The holotype male (unique) is deposited in CAS. This specimen was
collected by Hugh B. Leech, August 15, 1952.

Diagnosis. - Aedeagal form (Fig. 77A) and lack of a median depression of abdominal
sternum 6 in males are distinctive features.

Description. — Form: Broadest near posterior angles of pronotum, sides of elytra nearly straight. Size: Holotype
1.28 mm long, 0.64 mm wide. Color: Dorsum and venter black, legs and palpi brown. Head: Finely punctulate, finely
microreticulate. Pronotum: Finely punctulate, finely microreticulate. Elytra: Finely punctulate, microreticulation more
apparent than that of head; apices truncate. Metasternum : Small non-pubescent area in front of hind coxae. Abdomen:
Sternum 6 with small tuft of hairs in midline at posterior border, median depression absent. Genitalia: Male (Fig. 77A)(1
examined).

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Figs. 78A - B, Geographical distributions of Limnebius species. (A) L. angustulus • , L. texanus ★ and L. aridus A
(B) L. ozapalachicus #, L. discolor ★ and L. richmondi A-

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Variation. - Females have the elytral apices arcuate laterally.

Distribution. - (Figs. 78A,175). Known only from the type-locality in New Mexico, U.S.A.

Etymology. - Latin, aridus (dry). I refer to the arid habitat.

15. Limnebius mexicanus new species

(Figs. 74,77D,175)

Type-locality. - One mile N. Ixtlan de Juarez, Oaxaca, Mexico.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. Paratypes from the same locality are deposited in USNM (2), CAS (2), MCZ (2),
CNC (2), CFMNH (2) and PDP (20). These specimens were collected by my wife Maureen
and I, July 5, 1974.

Diagnosis. - Aedeagal form (Fig. 77D) and presence of a median depression on the
abdominal sternum 6 of males are distinctive characteristics.

Description. — Form: Broadest at posterior angles of pronotum, sides of elytra rather straight. Size: Holotype
1.20 mm long, 0.60 mm wide. Color: Dorsum and venter black, legs brown. Head: Finely punctulate, very finely
microreticulate. Pronotum: Finely punctulate, very finely microreticulate, especially on disc. Elytra: Finely punctulate,
microreticulation fine but more apparent than on head; apices truncate. Metasternum'. Pubescent throughout, hairs in
midregion longer than those laterally. Abdomen: Sternum 6 with large median depression, posterior border of which
pubescent. Genitalia: Male (Fig. 77D)(15 examined).

Variation. - Females have the elytral apices arcuate laterally.

Natural History. - These specimens were collected at the margin of a stream in an open,
pine-oak habitat.

Distribution. - (Figs. 74,175). Known only from the type-locality.

Etymology. - Latin, adjective, mexicanus , in reference to the geographical distribution.

16. Limnebius octolaevis new species

(Figs. 74,77C,175)

Type-locality. - 25 mi. S. Huehuetenango, Totonicapan, Guatemala.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. My wife Maureen and I collected these specimens, July 1, 1974. Paratypes (31) are
listed in the appendix.

Diagnosis. - Aedeagal form (Fig. 77C), shiny pronotal disc, and presence of a median
depression on abdominal sternum 6 in males are distinctive features.

Description. — Form: Broadest near posterior angles of pronotum, sides of elytra nearly straight. Size: Holotype
1 .44 mm long, 0.66 mm wide. Color: Dorsum and venter black, legs and palpi brown. Head: Finely punctulate, very finely
microreticulate. Pronotum: Finely, but very distinctively punctulate, very finely microreticulate laterally, shiny disc not
reticulate. Elytra: Finely punctulate, microreticulation fine, but more apparent than that of head; apices truncate.
Metasternum'. Small non-pubescent area in front of hind coxae. Abdomen: Sternum 6 with large median depression.
Genitalia: Male (Fig. 77C)(20 examined).

Variation. - Females have the elytral apices arcuate laterally.

Natural History. - The topotypical specimens were collected at the margins of a small, very
rapid stream.

Distribution. - (Figs. 74,175). Guatemala.

Etymology. - Latin, octo (eight) plus laevis (smooth). I refer to the smooth pronotum and
its eight marginal sensilla. (six along the posterior margin, two at the anterior margin; cf.
Fig. 69 A, L. octolaevis apparently lacks the anterolateral pair seen in L. sinuatus ).

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Figs. 79A - B, Aedeagi of Limnebius alutaceus. (A) specimen from Curry County, Oregon. (B) specimen from British
Columbia, Canada (drawn from holotype of L. columbianus Brown).

GENUS GYMNOCHTHEBIUS D’ORCHYMONT

Gymnochthebius d’Orchymont, 1943b:38 (type-species: Ochthebius nit id us LeConte; new status). - d’Orchymont, 1943b.

- J. Balfour- Browne, 1971.

Discussion. - D’Orchymont (1943b) erected this taxon as a subgenus of Ochthebius based
upon form of the male genitalia, which differs in basic plan from all other subunits of the genus
Ochthebius (cf. Figs. 84A-D,100A-D). Males of Gymnochthebius have the “main-piece” or
“median lobe” bifurcate at its apex and generally with the gonopore located in the notch
between the forks. Ochthebius males, on the other hand, have the main-piece tapered to a point,
with the gonopore situated at the apex of a preterminal, mobile process.

I have found, also, that the ejaculatory duct in Gymnochthebius is sclerotized, forming a
rigid tube. Of the more than 175 specimens of various species I have dissected, one specimen of
G. germaini (Fig. 85D) has this duct extended and I suspect that all males which have a
tubuliform internal duct have the ability to extend this duct during copulation.

That the extended condition is so rarely seen probably relates to muscle contraction caused
by alcohol in which these beetles are preserved upon capture. Proposing this function may seem

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unwarranted since only a single specimen in the extended position has been studied, however,
the differences in shape of the internal tube between species suggest also that the actual form of
the tube is related to its function. The distinctive shapes of the tubes between species can be
likened to the distinctive shapes of the terminal mobile process in species of Ochthebius.

In one subdivision of Gymnochthebius ( plesiotypus Subgroup), the internal structure is not
tubuliform but rather cupuliform (Figs. 81A-B,82A). I suspect that members of this group do
not have the ability to extend the internal cupuliform structure. This group also differs from the
other species in the genus by the abdominal sternum 5 being totally hydrofuge pubescent, and
the main-piece of the aedeagus bilaterally symmetrical. In the remaining species the abdominal
sternum 5 is at least partially ( germaini Group) or totally ( nitidus Group) without hydrofuge
pubescence , and the main-piece of the aedeagus is curved, bilaterally asymmetrical
(Figs. 84A-D).

In those species whose males have a bilaterally symmetrical main-piece of the aedeagus, and
the internal structure is cupuliform (G. plesiotypus, G. jensenhaarupi , and G. octonarius),
there are three features which are more closely similar to Ochthebius than to the remaining
members of Gymnochthebius. First, the parameres are inserted on the dorsal surface of the
aedeagus (in a morphological sense), as in Ochthebius males (cf. Figs. 81 A-B,100A-D). Males
of the more derived species of Gymnochthebius , however, have the parameres attached at the
sides of the aedeagus and they are extended along the sides to the apex (Figs. 84A-D).

Secondly, the pronotum of adults of this less derived group of Gymnochthebius is shaped
similarly to that of adults in Ochthebius (sensu stricto)(cf. Figs. 80E,82B-C,1 19A-H). In more
derived groups of Gymnochthebius , the lateral depressions of the pronotum develop into the
digitiform lobes so characteristic of the majority of the genus
(Figs. 80A-D,F,83A-F,89A-H,96B). Lastly, species in the plesiotypus Group of
Gymnochthebius have abdominal sternum 5 totally hydofuge pubescent as do the great
majority of Ochthebius. In the two other groups of Gymnochthebius the hydrofuge pubescence
of abdominal sternum 5 is either partially ( germaini Group) or totally ( nitidus Group) lost.

The aedeagus of plesiotypus Group males with its bifid apex and lack of a terminal process,
however, clearly indicates its proper placement within Gymnochthebius.

Consequently, based upon morphological evidence there appears to be two phylogenetic
lineages, Gymnochthebius and Ochthebius. Based upon structure of the less derived lineage
within Gymnochthebius ( plesiotypus Group), one can infer that the common ancestry is at the
base of Ochthebius and, therefore, Gymnochthebius does not constitute a specialized group
within Ochthebius. Stated differently, the probability of Gymnochthebius having arisen from
within a species-group of Ochthebius is remote. Contrarily, the probability of the two lineages
being worthy of equal rank is great.

If one turns now to zoogeographic evidence, the argument for equal rank of the two lineages
becomes even more convincing. Gymnochthebius is found in the Western Hemisphere and
Australia (d’Orchymont, 1943b). Within the Western Hemisphere the more primitive
sub-lineage of Gymnochthebius , the plesiotypus Group, is restricted to the Andes of southern
Chile and adjacent Argentina. Northward in Central and North America, the lineages are
increasingly derived. One can postulate that the distribution is an austral Gondwanian pattern
and, therefore, the origin of Gymnochthebius predates continental drift.

Those species of Ochthebius now known from South America (O. lineatus and O. attritus)
are restricted to northern parts of the continent. Adults of both of these species are vagile,
relatively widespread in North and Central America, and both are derived from a lineage

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Figs. 80A - F, Gymnochthebius body outlines. (A) G. reticulatissimus. (B) G. bartyrae. (C) G. reticulatus, (D) G. topali.
(E) G. plesiotypus. (F) G. compactus.

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within North America. I suspect that other species of Ochthebius will be found in northern
South America, but that they, also, will be derived from stocks in Central America and the
Antilles, and have arrived in northern South America in relatively recent times. Ochthebius is
absent from the remainder of South America, additional evidence that Gymnochthebius did not
arise as a sub-lineage of Ochthebius (refer to the section on phylogeny and zoogeography for
further comments).

Of the 25 species of Gymnochthebius now known from the Western Hemisphere, 16 are
restricted to South America, two to Central America, six to North America, and one (G.
fossatus) is widespread in North, Central and South America. Fourteen new species are
described in the genus, and two instances of new synonomy are reported.

Pronotal features. - Most primary features of Gymnochthebius pronota are quite similar to
those of Ochthebius, and the illustrated pronotum of Ochthebius (Fig. 98A) will suffice in
general respects. One outstanding difference in adults of the two genera is differentiation of the
lateral depressions into an anterior and posterior lobe in Gymnochthebius (e.g. nitidus ,
Fig. 96B), which occurs in certain lineages. Less derived pronota (e.g. plesiotypus. Fig. 80E) do
not have these well differentiated lobes. Adults of some species lack posterior foveae (e.g.
maureenae. Fig. 89A).

Diagnosis. - Form of the aedeagus, (with the main-piece bifid at the apex to form
moderately defined lobes, and with the internal duct formed as a process between these lobes) is
the single unifying characteristic which will invariably distinguish males of Gymnochthebius
from those of other species of Ochthebiinae. The aedeagus of Ochthebius males, the genus most
likely to be confused with Gymnochthebius, differs significantly in that the main-piece is not
bifid at the apex and the internal duct is extended beyond the main-piece to form a preterminal
mobile piece. In addition, the parameres are longer than the main-piece in Gymnochthebius,
but shorter than the main-piece in Ochthebius (Figs. 84A-D,100A-D). Externally, the pronotal
form is unique in adults of many species of Gymnochthebius (see generic
key)(Figs. 80A-F,89A-H) and is not easily confused with that of Ochthebius adults. Degree of
hydrofuge pubescence on the abdominal sternum 5 differs in the two genera, as discussed
above.

Description. — Form: Generally elongate-oval, adults of some species sub-truncate, moderately convex
(Figs. 80A-F,89A-H). Size: Length 1.20-2.24 mm, width 0.64-1.00 mm. Females generally slightly larger than males.
Color: Most adults dark brown, few black or testaceous. Head: Varied from nearly impunctate and shiny to coarsely
punctate and markedly microreticulate. Interocular foveae moderately developed. Interocular tuberculi (ocelli) evident.
Clypeus length of most adults 0.50 width, sides convergent anteriorly. Labrum of most males upturned in anteromedian
region, less so or not upturned in females. Maxillary palpus short, palpomere 3 distinctly thickened. Mentum width
generally equal length, anterior margin straight or slightly arcuate to rear. Genae shining, swollen. Antennomeres nine
(4 + 5). Thorax: Pronotum with well developed lateral hyaline margin, sclerotized portion varied from non-incised in
anterior 0.50 (Fig. 80E), to deeply incised (Fig. 96B). Anterior margin of most adults slightly bisinuate in habitus view,
anterior angles of many adults lobe-shaped. Lateral depressions of most adults impressed for length of pronotum, in few
adults reduced to small foveae at anterior. Disc of most adults with well developed anterior and posterior foveae, and
median groove; few adults without posterior foveae. Prosternum with median carina ended at coxal cavities; coxae
contiguous. Metasternum hydrofuge pubescent in midregion or not. Elytra: Disc generally with six prominent rows of
punctures between suture and humeri, each puncture with seta, few specimens with rows of punctures absent or greatly
reduced; microreticulation varied from very coarse to absent. Explanate margin moderately developed. Abdomen: Sternum
6 and 7 without hydrofuge pubescence. Hydrofuge pubescence of sternum 5 either total, reduced to anterior 0.50, or
absent. Sternum 7 of many adults with an admedian row of setae. Legs: Moderately long and slender. Males without
distinctive protarsal pads of suction setae; metatibiae unmodified. Genitalia: Aedeagus with main-piece bifid, internal
structure tubuliform or cupuliform, placed in lumen between forks. Spermatheca as illustrated (Figs. 9A-1).

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Key to Western Hemisphere species of Gymnochthebius

1 ( 0 ) Abdominal sternum 5 without hydrofuge pubescence; pronotum with

pronounced, digitiform anterior lobe (Figs. 89A-H,96B); North, Central and

South America ( nitidus Group) 2

V Abdominal sternum 5 entirely covered with hydrofuge pubescence, or with
hydrofuge pubescence in anterior 0.50; pronotum with anterior lobe more
rounded, less digitiform (Figs. 80A-C,E-F, 83A-F); South America 10

2 ( 1 ) Pronotal lateral depressions with posterior lobe larger than anterior lobe

(Figs. 89D,E); elytral intervals subcostate; size smaller, form truncate; Mexico,

Florida ( oppositus Subgroup) 3

2' Lateral depressions with posterior lobe much smaller than anterior lobe

(Figs. 89A-C,F-H); elytral intervals flat; size larger, form more elongate .... 4

3 ( 2 ) Elytral intervals more elevated, each with row of decumbent setae; elytral

margins with dense fringe of decumbent setae for entire length; Everglades,

Florida (Figs. 89D,95C) G. seminole, new species, p. 290

3' Elytral intervals less elevated, each with row of adpressed setae; elytral margins
with fringe of decumbent setae less apparent; Baja California, Mexico;

Veracruz, Mexico; and Brownsville, Texas (Figs. 89E,93A)

G. oppositus , new species, p. 289

4. ( 2') Elytra virtually impunctate ( laevipennis Subgroup) 5

4' Elytra with rows of punctures ( nitidus Subgroup) 8

5 ( 4 ) Pronotum without posterior foveae 6

5' Pronotum with well developed posterior foveae; Costa Rica (Figs. 89B,93I) . . .

G. perlabidus , new species, p. 286

6 ( 5 ) Dorsal surface dull; anterior margin of pronotum arcuate; Mississippi

(Figs. 89A,93J)

G. maureenae, new species, p. 287

6' Dorsal surface shiny; anterior margin of pronotum markedly bisinuate 7

7 (6') Pronotum without anterior foveae; anterior lobe of lateral depression deflexed;

Guatemala (Figs. 93B-C) G. crassipes (Sharp), p. 284

T Pronotum with anterior foveae; anterior lobe of lateral depression not deflexed;
coastal mountain ranges, southern Oregon, California and Baja California
(Figs. 89C,93E,G,H) G. laevipennis (LeConte), p. 283

8 ( 40 Elytra very convex; pronotum convex; Canada and northern and eastern United

States (Figs. 89H,93D,F) G. nitidus (LeConte), p. 274

8' Elytra and pronotum less convex, somewhat depressed; North, Central and

South America 9

9 ( 80 Larger, approximately 1.70 mm long; more depressed; aedeagus and habitus as

illustrated (Figs. 89F,91G); Arizona, Texas and Kansas

G. falli, new species, p. 28 1

9' Smaller, approximately 1.30 mm long; less depressed; aedeagus and habitus as

illustrated (Figs. 89G,91A-F); North, Central and South America

G.fossatus (LeConte), p. 277

10 (10 Abdominal sternum 5 and metasternum entirely covered with hydrofuge

pubescence; size large, body broad; Chile and Argentina

(plesiotypus Group) 11

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10' Abdominal sternum 5 with hydrofuge pubescence in anterior 0.50 only,
posterior 0.50 glabrous; metasternum with large median glabrous area; size
medium to large; South America ( germaini Group) 13

11 (10 ) Pronotal foveae large, markedly microreticulate (Figs. 80E,82A); elytra deeply

striate-punctate throughout G. plesiotypus , new species, p. 251

11' Pronotal foveae small, slightly microreticulate at most (Figs. 82B-C); elytra not

deeply striate-punctate 12

12 (11') Pronotal lateral depressions extended further posterior (Figs. 81A,82B); elytral

rows of punctures very fine, separated by two-three times puncture diameter,

not in striae; body broader G. octonarius, new species, p. 254

12' Pronotal lateral depressions shorter (Figs. 81B,82C); elytra with rows of larger
punctures, separated by 0.5- 1.0 times puncture diameter; striae moderately deep

in anterior 0.50 of elytron, very shallow on remainder; body narrower

G. jensenhaarupi (Knisch), p. 253

13 (10') Pronotum quadrate, entire surface coarsely microreticulate; large, robust

species (Figs. 80A,C); Argentina ( reticulatus Subgroup) 14

13' Pronotum less quadrate, microreticulation absent from areas between anterior
and posterior foveae of side, at least, in most specimens restricted to foveae or
absent; South America {germaini Subgroup) 15

14 (13 ) Elytral intervals costate, rows of punctures obscured by well developed

microreticulation; pronotum uniformly microreticulate, dull (Figs. 80A,88C). .

G. reticulatissimus, new species, p. 273

14' Elytral intervals rounded, not costate, rows of punctures clearly defined, not
obscured by microreticulation; pronotal disc with microreticulation slightly
effaced, hence slightly more reflective than remainder of pronotum

(Figs. 80C,88A) G. reticulatus, (d’Orchymont), p. 271

15 (13') Pronotum markedly convergent to base, markedly microreticulate except
between foveae of side (Figs. 80B,95A); posterior foveae very large, larger than

an eye; elytra maculate and with broad, shallow depression on disc; Peru

G. bartyrae , new species, p. 270

15' Pronotum less convergent to base, microreticulation much less developed
(Figs. 83A-F); posterior foveae smaller than an eye; elytra not maculate,
without broad depression on disc 16

16 (15') Pronotal anterior lobes digitiform (Figs. 80D,F,86A); pronotal reliefs very

convex 17

16' Pronotal anterior lobes rounded (Figs. 83A-F,86B-C); pronotal reliefs flat or

slightly convex 19

17 (16 ) Elytral intervals subcostate, or narrower than diameter of punctures in rows . 18

17' Elytral intervals flat, wider than diameter of punctures in rows (Figs. 85B,86A)

G. curvus, new species, p. 262

18 (17 ) Elytral intervals subcostate; body form convex, truncate (Fig. 80F); Brazil . . .

G. compactus, new species, p. 267

18' Elytral intervals narrow, zig-zag shaped due to large, deep, serial punctures;

body form not distinctively convex or truncate (Figs. 80D,90B); Chile

G. topali (J. Balfour-Browne), p. 265

19 (16') Elytra testaceous, at least in part 20

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19' Elytra brown, or dark brown 21

20 (19 ) Pronotum densely, coarsely punctate (Figs. 84C,86B); Peru

G. peruvianus (J. Balfour-Browne), p. 268

20' Pronotum very finely, sparsely punctate (Figs. 86C-E); Argentina

G.frahcki (Bruch), p. 264

21 (19') Pronotum with anterior lobes large (Figs. 83E,95B); pronotal microreticulation

nearly imperceptible in foveae and lateral fossulae; Colombia

G. bisagittatus, new species, p. 264

21' Pronotum with anterior lobes smaller (Figs. 83A-D,F); pronotal

microreticulation moderately to well developed in foveae and lateral fossulae;
Chile 22

22 (2F) Elytral intervals finely microreticulate, moderately dull; larger, approximately

1.88-2.00 mm 23

22' Elytral intervals without microreticulation, shiny; smaller, approximately

1.80 mm 24

23 (22 ) Body form parallel sided; ratio of elytral width to length approximately 1.0: 1.5;

microreticulation of elytra, pronotal foveae and fossulae less developed;
aedeagus with distal branches of equal length (Figs. 83B,84A)

G. chilenus , (J. Balfour-Browne), p. 257

23' Body form less parallel sided; ratio of elytra width to length approximately
1.0: 1.4; microreticulation of elytra, pronotal foveae and fossulae more
developed; aedeagus with distal branches of unequal length

(Figs. 83C-D,85A,C,D) G. germaini, (Zaitzev), p. 256

24 (22') Aedeagus larger, distal branches more widely separated, internal tube sinuate

(Figs. 83F,84B) G. clandestinus , new species, p. 258

24' Aedeagus smaller, distal branches less widely separated, internal tube arcuate

(Figs. 83A,88B) G. tectus, new species, p. 261

The plesiotypus Group

Members of this group have the metasternum and abdominal sternum 5 totally hydrofuge
pubescent. Adults of its three species are large (2.00-2.50 mm), black, with accessory pronotal
foveae well developed. The morphological gap separating G. plesiotypus from the closely
similar sister-species pair, G. jensenhaarupi - G. octonarius, is considerable, involving body
form (compare Figs. 80E, 82B,C) and sculpture. This large gap suggests that a number of
species remain to be discovered in this group, or that extensive extinction has occurred. Absence
of intensive collecting in the geographic area this group occupies leads me to suspect the
former. The aedeagus in this group is unusual in that the two lobes of the median portion are
symmetrical and straight, and the internal structure is cup-shaped, with a large terminal
opening (Figs. 81A,B,82A). I regard these genitalic characters as pleisotypic. Among the other
species in the subgenus, only males of G. reticulatus and G. reticulatissimus have straight,
nearly symmetrical aedeagi (Figs. 88 A, C). However, they have the internal structure

tube-shaped as do males of the remainder of the subgenus (see the remarks section of G.
reticulatus for comments regarding the apparent lack of an internal tube). Males of all other

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Figs. 81 A - B, Aedeagi of Gymnochthebius species. (A) G. octonarius, holotype. (B) G. jensenhaarupi, lectotype.

species of Gymnochthebius have the aedeagus sinuate in dorsal view, and asymmetrical (such
as in Figs. 84A-D).

Species of the plesiotypus Group live on the eastern slope of the Andes in Argentina and on
the western in Chile. The only habitat information available indicates that specimens of G.
plesiotypus were taken from pools adjacent to a river. This apparently lentic habitat preference
requires verification, as lotic species in the genus are frequently displaced downstream and
deposited in streamside pools.

1. Gymnochthebius plesiotypus new species
(Figs. 80E,82A,176A)

Type-locality. - Concepcion region, Chile.

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Type-specimens. - The holotype male is deposited in USNM; collector unknown. The
allotype, collected by G. Topal at El Bolson, Rio Negro Province, Argentina, is deposited in
USNM. Paratypes (6) have the same data as allotype and are deposited in HNHM, BMNH
and PDP.

Diagnosis. - Deeply striate-punctate elytra, large pronotal foveae and body form
(Figs. 80E,82B,C) serve to readily distinguish G. plesiotypus adults from those of G.
jensenhaarupi and G. octonarius , the only other species in the genus Gymnochthebius with
metasternum and abdominal sternum 5 totally hydrofuge pubescent.

Description. — Form: Elongate-oval, moderately depressed (Fig. 80E). Size: Holotype 2.02 mm long, 0.92 mm
wide. Color: Dorsum black; venter, legs and palpi dark brown. Head: Length 0.38 mm; width 0.50 mm. Frons markedly
microreticulate, finely sparsely punctate, very sparsely pubescent; interocular foveae deep and large, width of each 0.50
distance between them; interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture evenly arcuate.
Clypeus length 0.50 width, markedly microreticulate. Labroclypeal suture straight. Labrum length 0.33 width; markedly
microreticulate, sparsely pubescent; median emargination well developed, edge slightly upturned. Maxillary palpus with
palpomere 2 moderately wide; palpomere 4 0.50 length of palpomere 3. Mentum width equal length, shining, finely
sparsely punctate, markedly microreticulate; anterior margin very slightly arcuate. Submentum evenly, finely punctulate,
punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.44 mm;
maximum width (near anterior 0.33) 0.62 mm. Anterior hyaline border narrow in front of disc, slightly wider in front of
lateral fossulae. Lateral hyaline border very narrow, origin near midlength of lateral depressions. Anterior margin of
pronotum slightly arcuate to rear. Lateral depressions with evenly rounded margins, very small tooth at posterior extreme;
microreticulate. Pronotum moderately constricted behind lateral depressions. Lateral fossulae deep, arcuate, markedly
microreticulate, inner margin abrupt, outer margin slightly defined, posterior extreme extended to lateral hyaline border.
Pronotal disc moderately shiny, slightly convex, extremely finely, extremely sparsely punctate, faintly microreticulate,
sparsely pubescent. Median groove markedly microreticulate, deep, moderately wide, slightly constricted in midregion.
Anterior foveae oval, deep, markedly microreticulate, width equal distance between fovea and median groove. Posterior
foveae deep, length twice width, length three times that of anterior fovea, markedly microreticulate. Posterolateral angles
with very shallow impressions. Prosternum with median carina ending at coxal cavities; coxae contiguous. Metasternum
entirely covered with hydrofuge pubescence, without median glabrous area. Elytra: Length 1.36 mm; maximum width
(near midlength) 0.92 mm. Disc flat, moderately shiny, with six rows of punctures between suture and humeri, each
puncture with seta; rows of punctures microreticulate, as are intervals, latter less so. Declivity origin near posterior 0.33.
Intervals rounded, slightly elevated, width equal puncture width. Interstices between punctures obscured by
microreticulation. Explanate margin moderately developed. Abdomen: Basal five sterna entirely covered with hydrofuge
pubescence. Sternum 6 shiny, sparsely pubescent. Sternum 7 shiny; setae of submedian setal groups moderately short.
Legs: Moderately long and slender; ratio of hind leg length to abdominal length 1.8/1. Protarsomeres 1-3 without suction
setae. Genitalia: Male (Fig. 82A)(3 examined).

Variation. - The specimens from El Bolson, Argentina are much larger than the holotype,
males and females approximately 2.50 mm long. Additionally, the Argentinian specimens have
the dorsal microreticulation more evident and are, therefore, somewhat duller than the
holotype. However, the aedeagi of the two Argentinian males I have studied are virtually
identical in all respects, including shape of the internal structure, to that of the holotype.
Consequently, I believe these specimens represent a single species. Males are easily
distinguished from females by the two rows of submedian setae on abdominal sternum 7 and
the more narrowly explanate elytral margin.

Natural History. - J. Balfour-Browne (1971) reports that the Argentinian specimens are
“from water in pool in inundated area of Rio Quemquemtrei” and “from under stones and from
mud near stagnant water of Rio Quemquemtrei”.

Distribution. - (Fig. 176A). Known from Concepcion Province, Chile and Rio Negro
Province, Argentina.

Etymology. - Latin, plesio (near) plus typus (model). Adults of this species have a
combination of three morphological features one might suspect to be present on a “primitive
model” of the common ancestor of Gymnochthebius and Ochthebius : 1) pronotal form, which is
virtually identical to that seen in the majority of species of Ochthebius (sensu stricto) Leach; 2)

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aedeagal form, which is bilaterally symmetrical, except for the internal structure, and is
bilobed; and 3) abdominal sternum 5 covered with hydrofuge pubescence.

Remarks. - J. Balfour-Browne (1971) discussed and illustrated this species under the name
G. jensenhaarupi Knisch. He mentioned the discrepancy between features of the elytra of the
specimens and Knisch’s description, then stated that “so close is the agreement of the gentalia
with d’Orchymont’s figure, that I hesitate to treat these specimens as representing a new
species without a direct comparison with Knisch’s type”. The genitalia of the two species
(Figs. 82A,C), however, are quite distinct. This serves to point out the need to illustrate the
aedeagi in two views and with much more detail than has been provided in previous works.

2. Gymnochthebius jensenhaarupi (Knisch)

(Figs. 81B,82C,176A)

Ochthebius jensenhaarupi Knisch, 1924:1 14 (lectotype male in ISNB, here designated; type-locality: Station Santa Rosa,

Mendoza, Mendoza Province, Argentina). d’Orchymont, 1943:38. -J. Balfour-Browne, 1971:180.

Diagnosis. - Totally pubescent abdominal sternum 5 and metasternum, together with large

size, shiny black dorsum and unusual pronotal shape serve as diagnostic characteristics to
readily distinguish G. jensenhaarupi adults from those of all Gymnochthebius species except G.
octonarius, its putative sister-species. Adults are very similar to those of G. octonarius in most
features, but differ slightly in pronotal, elytral and aedeagal form. The pronotal lateral
depressions of G. octonarius adults extend further posterior, causing the lateral hyaline borders
to originate at approximately the midlength of the pronotum, whereas the lateral depressions of
G. jensenhaarupi adults are shorter, the lateral hyaline border having its anterior extreme near
the anterior 0.33 of the pronotum (Figs. 82B,C). The posterior foveae are more apparent in G.
jensenhaarupi , in the few specimens studied. The elytra of G. jensenhaarupi adults are
striate-punctate, the striae very lightly impressed on the disc, more deeply impressed in the
anterior 0.20; the elytral punctures are larger, the spaces between punctures of a row 0.5-1. 0
times puncture diameter and the rows separated by one-two times puncture diameter. In
contrast, the elytra of G. octonarius adults have very small, lightly impressed, widely separated
serial punctures which are not in striae; both the distance between punctures of a row and that
between punctures of adjacent rows are two-three times puncture diameter. Another external
difference between the types of the two species is shape of the labroclypeal suture, which is
straight in G. octonarius and distinctly arcuate to rear in G. jensenhaarupi’, further specimens
are needed to verify the constancy of this apparent difference. The aedeagus of G.
jensenhaarupi, when compared to that of G. octonarius (Figs. 81A,B), gives the visual
impression that most of the structure has been extended further toward the apex; therefore the
aedeagus, in both dorsal and lateral views, tapers more abruptly to the apex in G.
jensenhaarupi. Additionally, the internal aedeagal tube is shaped differently in these putative
sister-species.

Description. — Form: Elongate-oval, moderately convex (Fig. 82C). Size: Lectotype 2.20 mm long and 0.96 mm
wide. Color: Dorsum and venter black; legs and palpi brown. Head: Length 0.38 mm; width 0.54 mm. Frons finely sparsely
punctate, very sparsely pubescent; interocular foveae deep and large, width of each nearly 0.66 distance between them;
interocular tuberculi large, but not well delimited; basomedial fovea very small. Frontoclypeal suture arcuate. Clypeus
length 0.50 width, finely sparsely punctate, sparsely pubescent. Labroclypeal suture distinctly arcuate to rear, anterior
angles acute. Labrum length 0.33 width; finely sparsely punctate, sparsely pubescent; median emargination slightly
developed, edge very slightly upturned. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 slightly greater
than 0.50 length of palpomere 3. Mentum width equal length, shining, finely densely punctate; anterior margin straight.
Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax:
Pronotum length at midline 0.50 mm; maximum width (near anterior 0.33) 0.66 mm. Anterior hyaline border narrow in

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front of disc, slightly wider in front of lateral fossulae. Lateral hyaline border origin near midlength of lateral
depressions, extended narrowly to posterior angles, very narrow around posterior margin. Anterior margin of pronotum
slightly arcuate in midregion. Lateral depressions broad, moderately long, with prominent tooth at posterior extreme;
surface between margin and fossula nearly impunctate. Pronotum slightly constricted behind lateral depressions. Lateral
fossulae deep, microreticulate, not extended to tooth at lateral hyaline border. Pronotal disc shiny, very slightly convex,
extremely finely, extremely sparsely punctate, sparsely pubescent. Median groove narrow, shallow, faintly
microreticulate. Anterior foveae small, deep, width 0.50 distance between fovea and median groove. Posterior foveae
shallow, linear impressions with very faint microreticulation; width 0.33 distance between fovea and median groove.
Posterolateral angles with deep, oval impressions, latter larger than anterior foveae. Four small, distinct, oval
depressions on disc, one posterior to each posterior fovea and one anterior to each anterior fovea (Fig. 82C). Prosternum
with median carina ended at coxal cavities; coxae contiguous. Metasternum entirely covered with hydrofuge pubescence,
without median glabrous area. Elytra: Length 1.44 mm; maximum width (near midlength) 0.96 mm. Disc flat, shiny,
with six rows of round punctures between suture and humeri, each puncture with seta. Declivity origin near posterior
0.33. Intervals flat, width one-two times puncture width. Interstices between punctures 0. 5-1.0 times puncture diameter.
Rows of punctures in striae very lightly impressed on disc, more deeply impressed in anterior 0.50 of elytra. Abdomen:
Basal five sterna entirely covered with hydrofuge pubescence. Sternum 6 shiny, sparsely pubescent. Sternum 7 shiny;
setae of submedian setal groups long. Legs: Moderately long and slender; ratio of hind leg length of abdominal length
2.0: 1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 8 1 B)( 1 examined).

Distribution. - (Fig. 176A). Known only from the type-locality in Mendoza Province of
western Argentina.

Remarks. - The discussion and figures presented by J. Balfour-Browne (1971), based upon
specimens which he presumed to be Ochthebius jensenhaarupi, are actually based upon
specimens of G. plesiotypus, described herein. Other than the lectotype, I have seen but a single
female of G. jensenhaarupi.

3. Gymnochthebius octonarius new species
(Figs. 81 A, 82B, 176 A)

Type-locality. - 15 km. W. Tucuman, Tucuman Province, Argentina.

Type-specimens. - The holotype male, allotype and seven paratypes, all with identical
locality data, are deposited in USNM. These specimens were collected by Paul and Phyllis
Spangler, May 22, 1969.

Diagnosis. - Large size, shiny black dorsum with unusual pronotal shape (Fig. 82B)
together with totally hydrofuge pubescent metasternum and abdominal sternum 5 readily
distinguish G. octonarius adults from those of all Gymnochthebius species except G.
jensenhaarupi , its putative sister-species. Refer to the diagnosis of G. jensenhaarupi for a
comparison of these two species.

Description. — Form: Elongate-oval, moderately convex (Fig. 82B). Size: Holotype 2.24 mm long, 1.00 mm wide.
Color: Dorsum and venter black; legs and palpi brown. Head: Length 0.40 mm; width 0.56 mm. Frons finely moderately
sparsely punctate, very sparsely pubescent; interocular foveae deep and large, width of each nearly 0.66 distance between
them; interocular tuberculi large; basomedial fovea very small. Frontoclypeal suture evenly arcuate. Clypeus length 0.50
width, finely sparsely punctate, sparsely pubescent. Labroclypeal suture straight. Labrum length 0.33 width; finely
sparsely punctate, sparsely pubescent; median emargination slightly developed, edge upturned. Maxillary palpomere 3
moderately wide; palpomere 4 0.50 length of palpomere 3. Mentum width equal length, shining, finely densely punctate;
anterior margin straight. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.50 mm; maximum width (near anterior 0.33) 0.72 mm. Anterior
hyaline border narrow in front of disc, slightly wider in front of lateral fossulae. Lateral hyaline border origin near
posterior 0.33 of lateral depressions, extended narrowly to posterior angles, very narrow around posterior margin. Anterior
margin of pronotum straight in midregion, broadly excavate in front of lateral depressions. Lateral depressions broad, long,
with prominent tooth at posterior extreme; surface nearly impunctate. Pronotum weakly constricted behind lateral
depressions. Lateral fossulae deep, microreticulate, inner and outer margins equally, moderately abrupt, posterior extreme
extended nearly to tooth at lateral hyaline border. Pronotal disc shiny, very slightly convex, extremely finely, extremely
sparsely punctate, sparsely pubescent. Median groove narrow, shallow, microreticulate. Anterior foveae circular, deep,
small, width 0.50 distance between foveae and median groove. Posterior foveae very small and indistinctly defined,
consisting of series of three or four punctures, lightly impressed. Posterolateral angles with distinct, shallow, circular fovea.

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255

Figs. 82A - C. (A) Gymnochthebius plesiotypus , aedeagus of holotype. (B) G. octonarius body outline. (C) G.
jensenhaarupi, body outline.

diameter 0.33 distance between fovea and median groove, diameter equal that of anterior foveae, extremely faintly
microreticulate. Four small, distinct, oval depressions on disc, one posterior to each posterior fovea and one anterior to
each anterior fovea (Fig. 82B). Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum
covered with hydrofuge pubescence, without median glabrous area. Elytra: Length 1.48 mm; maximum width (near
midlength) 1.00 mm. Disc flat, shiny, with six rows of small round punctures between suture and humeri, each puncture
with seta. Declivity origin near posterior 0.33. Intervals flat, width two-three times puncture diameter. Interstices
between punctures two-three times puncture diameter. Explanate margin moderately developed. Abdomen: Basal five
sterna covered with hydrofuge pubescence. Sternum 6 shiny, sparsely pubescent. Sternum 7 shiny; setae of submedian
setal groups long. Legs: Moderately long and slender; ratio of hind leg length to abdominal length 2.0: 1.0.
Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 81A)(2 examined).

Variation. - Some paratypes lack posterior foveae.

Distribution. - (Fig. 176A). Known only from the type-locality in Tucuman Province,
northwestern Argentina.

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Etymology. - Latin, octonarius (consisting of eight). I refer to the eight prominent foveae of
the pronotum, consisting of four “accessory” foveae (pronotal sensilla) plus the two anterior
foveae and the single prominent fovea at each posterolateral angle. The very faint posterior
foveae are not included in this group of eight.

The germaini Group

The single unifying character which indicates that this aggregate of species is a natural
group is distribution of hydrofuge pubescence on abdominal sternum 5: present on the anterior
one-half, and absent from the posterior one-half. Additionally, adults of all species have the
median region of the metasternum glabrous, and most have the anterior pronotal lobes
moderately digitiform, midway in form between the more rounded lobes of the plesiotypus
Group and the more digitiform lobes seen in the nitidus Group. Adults of one species in this
group, O. compactus from Brazil, is rather similar in habitus appearance to those of certain
species in the nitidus Group, which suggests that perhaps species uniting the two groups may be
awaiting discovery in the neotropics. Adults of several species, especially some from Chile, are
very similar in habitus and require examination of the aedeagus for positive identification. The
group as a whole, however, is structurally quite diverse, with most differences relating to shape
of the pronotum, but with other very distinctive character states expressed in certain species.
These varying character states include degree of development of microreticulation and pronotal
foveae, degree of flatness of lateral depressions, degree of elevation of elytral intervals, and
body size.

Species in this group live in Argentina, Brazil, Colombia, Chile and Peru. Further collecting
will probably reveal that the group range also includes montane regions of South America.

The germaini Subgroup

Members of the germaini Subgroup have the dorsal microreticulation generally very
reduced ( G . bartyrae is a notable exception) and are usually medium sized (1.50 - 1.80 mm).
The aedeagus is sinuate and asymmetrical in dorsal view, and has the parameres lying along
the sides of the median portion.

Currently there are 1 1 species representing this subgroup.

4. Gymnochthebius germaini (Zaitzev)

(Figs. 9E,83C,D,85A,C,D,87A,177)

Ochthebius aeneus Germain, 1855:390 (nec Stephens 1835).

Ochthebius sulcicollis Germain, 1901:530 (nec Sturm 1836).

Ochthebius germaini Zaitzev, 1908:530 (holotype female deposited in MHNC; type-locality: Quillota, Valparaiso
Province, Chile). d’Orchymont, 1929:100. - d’Orchymont, 1943:37. -J. Balfour-Browne, 1971:177.

Mr. J. Balfour-Browne has discussed this species and established the type-specimen; I

accept his conclusion.

Diagnosis. - G. germaini is one of four Chilean species whose adults are very difficult to
distinguish from one another using external features. The other three species in this
troublesome aggregate are G. chilenus, G. clandestine, and G. tectus. Using external features,

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257

one can perhaps recognize G. germaini and G. chilenus after a representative number of males
have been dissected and the aedeagi studied to assure proper species assignment. However, it is
probably impossible at present to adequately communicate the subtle external differences
between these four species. All determinations made regarding these four species should be
based upon study of the male genitalia.

Description. — Form: Ovate, moderately convex (Figs. 83C,D). Size: Holotype 1.82 mm long, 0.84 mm wide.
Color: Dorsum and venter dark brown; legs, palpi and elytral epipleura brown. Head: Length 0.34 mm; width 0.48 mm.
Frons finely sparsely punctate, very sparsely pubescent, microreticulate laterally; interocular foveae deep and large, width
of each nearly 0.66 distance between them; interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture
evenly arcuate. Clypeus length 0.50 width, finely sparsely punctate, sparsely pubescent. Labroclypeal suture straight.
Labrum length 0.33 width; finely sparsely punctate, sparsely pubescent; median emargination moderately developed, with
upturned edge, labrum evenly rounded in habitus view. Maxillary palpus with palpomere 3 moderately wide; palpomere 4
0.50 length of palpomere 3. Mentum width equal length, shining, finely sparsely punctate; anterior margin arcuate.
Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax:
Pronotum length at midline 0.46 mm; maximum width (near anterior 0.33) 0.64 mm. Anterior hyaline border moderately
wide in front of disc, slightly wider in front of lateral fossulae. Lateral hyaline border origin near midlength of anterior
lobe of lateral depressions, moderately arcuate to posterior lobe, more strongly arcuate to posterior angles, very narrow
around posterior margin. Anterior margin of pronotum slightly arcuate. Lateral depressions finely sparsely punctate,
sparsely pubescent; anterior lobe width equal length, much larger than posterior lobe, anterior extreme arcuate; posterior
lobe angulate, forming nearly a 90 degree angle. Pronotum moderately constricted behind lateral depressions. Lateral
fossulae deep, markedly microreticulate, inner margin abrupt, outer margin well demarcated, inner and outer margins
nearly parallel. Pronotal disc shiny, slightly convex, moderately sparsely, moderately finely punctate, sparsely pubescent.
Median groove narrow, moderately shallow, faintly microreticulate. Anterior foveae oval, deep, width 0.50 distance
between fovea and median groove. Posterior foveae deep, length two-three times width, length twice that of anterior fovea,
microreticulate. Posterolateral angles with very shallow impressions. Prosternum with median carina ended at coxal
cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra: Length 1.20 mm; maximum width (near
midlength) 0.84 mm. Disc flat, moderately shiny, with 6 rows of round punctures between suture and humeri, some
punctures subconfluent, each puncture with seta. Declivity origin near posterior 0.33. Intervals flat, width equal puncture
width; interstices between punctures 0.25 puncture length, or less. Explanate margin moderately developed. Abdomen:
Basal four sterna entirely covered with hydrofuge pubescence. Sternum 5 with posterior arc of glabrous area; anterior
limits of latter near midlength of segment in midline, near posterior angles laterally. Segment 6 shiny, sparsely pubescent.
Apical segment shiny; setae of submedian setal groups moderately long. Legs: Moderately long and slender; ratio of hind
leg length to abdominal length 1.6/ 1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male (Figs. 85A,C,D)(22
examined); female (Fig. 9E).

Variation. - I have seen one male from Rio Nirivilo, Maule Province, Chile which differs
greatly in external characteristics from the other specimens of G. germaini. These external
differences include: 1) shape of the pronotum (Fig. 83D)(anterior lobes much larger than
posterior lobes in G. germaini , nearly equal in size in this unusual specimen); 2) development of
microreticulation (less prominent in this specimen, especially in the lateral fossulae); 3) elytral
form ( G . germaini has closely spaced, deep rows of punctures, whereas the specimen in question
has widely spaced, shallow punctures); and 4) size (this specimen is much smaller, 1.56 mm
long vs 1.80 mm). However, I can detect no significant differences in the aedeagus of this
specimen (Figs. 85A,C). Therefore, despite these obvious external differences, I feel it is unwise
to describe this specimen as representing a new species without having large numbers of
specimens from throughout the range of G. germaini. Future collecting will undoubtedly
provide the specimens to resolve this problem.

Distribution. - (Figs. 87A,177). Chile. I have examined 60 specimens (see appendix for
locality data).

5. Gymnochthebius chilenus (J. Balfour-Browne)

(Figs. 9G,83B,84A,177)

Ochthebius chilenus J. Balfour-Browne, 1971:179 (holotype male deposited in MHNC; type-locality: Mininco, Malleco

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Province, Chile).

Diagnosis. - Specimens of G. chilenus can be reliably separated from those of G. germaini ,
G. clandestinus, and G. tectus only by referral to the aedeagus. Refer to the diagnosis of G.
germaini for further comments.

Description. — Form: Ovate, moderately convex (Fig. 83B). Size: Holotype 1.93 mm long and 0.84 mm wide.
Color: Dorsum black; venter dark brown; legs and palpi brown. Head: Length 0.38 mm; width 0.52 mm. Frons finely
moderately densely punctate, very sparsely pubescent, microreticulate laterally; interocular foveae moderately deep and
large, width of each 0.5 distance between them; interocular tuberculi large; basomedial fovea transverse. Frontoclypeal
suture evenly arcuate. Clypeus length 0.5 width, finely sparsely punctate, sparsely pubescent, markedly microreticulate
laterally. Labroclypeal suture straight. Labrum length 0.33 width; finely sparsely punctate, sparsely pubescent; median
emargination slightly developed, edge upturned, evenly rounded in habitus view. Maxillary palpus with palpomere 3
moderately wide; palpomere 4 0.5 length of 3. Mentum width equal length, shining, finely densely punctate; anterior
margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely
punctulate. Thorax: Pronotum length at midline 0.48 mm; maximum width (near anterior 0.33) 0.70 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral depressions, then tapered to anterior
angles. Lateral hyaline border beginning near anterior 0.33 of lateral depression, sides straight, slightly convergent; border
moderately wide in region of lateral depressions, wider at excavations, very narrow around posterior margin. Anterior
margin of pronotum slightly arcuate in midregion. Lateral depressions finely, moderately sparsely punctate; anterior lobe
slightly produced, wider than long, larger than posterior lobe, anterior extreme arcuate; posterior lobe angulate, angle
nearly right. Pronotum moderately constricted behind lateral depressions. Lateral fossulae deep, microreticulate, inner
margin abrupt, posterior extreme extended to lateral hyaline border. Pronotal disc shiny, slightly convex, moderately
finely, moderately densely pubescent. Median groove shallow, narrow, microreticulate. Anterior foveae moderately
elongate ovals, width equal 0.50 distance separating fovea and median groove. Posterior foveae deep, narrow, width 0.25
length, length twice that of anterior fovea, faintly microreticulate. Posterolateral angles with shallow impressions.
Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median glabrous area.
Elytra: Length 1.32 mm; maximum width (near midlength) 0.86 mm. Disc flat, shiny, with six rows of round punctures
between suture and humeri, each puncture with a seta. Declivity beginning near posterior 0.33. Intervals flat, width
slightly greater than puncture width; alternate intervals, beginning with second from suture, each with very sparse row of
setae. Interstices between punctures 0.25 puncture length. Explanate margin moderately developed. Abdomen: Basal four
sterna entirely covered with hydrofuge pubescence. Sternum 5 with posterior arc of glabrous area with anterior limits near
midlength of segment in midline, near posterior angles laterally. Segment 6 shiny, sparsely pubescent. Apical segment
shiny; setae of submedian setal group short. Legs: Moderately long and slender; ratio of hind leg length to abdominal
length 1.6/ 1.0. Protarsomeres 1 and 2 with weakly developed suction setae. Genitalia: Male (Fig. 84A)(9 examined);
female (Fig. 9G).

Distribution. - (Figs. 87A,177). Chile. Thirteen specimens were studied (see appendix).

6. Gymnochthebius clandestinus new species
(Figs. 9A,83F,84B,87B,149B,152B,177)

Type-locality. - Rio Nirivilo, Maule Province, Chile.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. These specimens were collected by H.P. Brown, November 2, 1971. Data about
paratypes (190) are presented in the appendix.

Diagnosis. - Genitalic characteristics must be used to reliably separate males of G.
clandestinus from those of three other Chilean species, G. germaini , G. chilenus and G. tectus.
Refer to the diagnosis of G. germaini for additional comments.

Description. — Form: Ovate, moderately convex (Fig. 83F). Size: Holotype 1.80 mm long, 0.80 mm wide. Color:
Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.34 mm; width 0.46 mm. Frons shiny, finely sparsely
punctate, very sparsely pubescent; interocular foveae deep, width of each 0.5 distance between them; interocular tuberculi
large; basomedial fovea transverse. Frontoclypeal suture angulate. Clypeus length 0.5 width, finely sparsely punctate,
sparsely pubescent. Labroclypeal suture straight. Labrum length 0.33 width; finely sparsely punctate, moderately sparsely
pubescent; median emargination moderately developed, edge upturned. Maxillary palpus palpomere 3 moderately wide;
palpomere 4 0.50 length of 3. Mentum width equal length, shining, finely sparsely punctate; anterior margin arcuate.
Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax:
Pronotum length at midline 0.40 mm; maximum width (near anterior 0.33) 0.62 mm. Anterior hyaline border moderately
wide in front of disc, slightly wider in front of area between anterior foveae and lateral fossulae. Lateral hyaline border

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0.5 mm

•Figs. 83A - F, Gymnochthebius body outlines. (A) G. tectus. (B) G. chilenus. (C) G. germaini. (D) G. germaini variant.
(E) G. bisagittatus. (F) G. clandestinus.

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0.1mm

Figs. 84A - D, Aedeagi of Gymnochthebius species. (A) G. chilenus. (B) G. clandestinus, holotype. (C) G. peruvianus,
holotype. (D) G. topali, holotype.

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261

extended from near midlength of anterior lobe of lateral depressions, moderately arcuate to posterior lobe, more
markedly arcuate to posterior angles, very narrow around posterior margin. Anterior margin of pronotum arcuate.
Lateral depressions sparsely finely punctate; anterior lobe wider than long, much larger than posterior lobe, anterior
extreme arcuate; posterior lobe angulate, angle nearly right. Pronotum moderately constricted behind lateral
depressions. Lateral fossulae deep, microreticulate, inner margin abrupt, outer margin well marked, posterior extreme
tapered into lateral hyaline border. Pronotal disc shiny, slightly convex, finely, sparsely punctate, sparsely pubescent.
Median groove narrow, shallow, faintly microreticulate. Anterior foveae oval, deep, moderately small, width 0.50
distance between fovea and median groove, anterior foveae deep, length three times width, length three times that of
anterior fovea, microreticulate. Posterolateral angles with very shallow impressions. Prosternum with median carina
ended at coxal cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra: Length 1.16 mm;
maximum width (near midlength) 0.80 mm. Disc flat, shiny, with six rows of small, round punctures between suture
and humeri, each puncture with a seta. Declivity beginning near posterior 0.33. Intervals flat, width twice puncture
width; interstices between punctures 0.25 puncture length. Explanate margin moderately developed. Abdomen: Basal
four sterna entirely covered with hydrofuge pubescence. Sternum 5 with posterior arc of glabrous area whose anterior
limits are near midlength of segment in midline, near posterior angles laterally. Segment 6 shiny, sparsely pubescent.
Apical segment shiny; setae of submedian setal group moderately long. Legs: Moderately long and slender; ratio of hind
leg length to abdominal length 2. 0:1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 84B)(42
examined); female (Fig. 9A).

Natural History. - Other than the descriptor “pond in field”, nothing is known of the
natural history.

Distribution. - (Figs. 87B,177). Chile.

Etymology. - Latin, clandestinus (secret, hidden). I refer to the closely similar external
characteristics of adults of G. clandestinus to G. germaini, G. chilenus and G. tectus.

7. Gymnochthebius tectus new species
(Figs. 9H,83A,87B,88B,177)

Type-locality. - Rio Nirivilo, Maule Province, Chile.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. These specimens were collected by H.P. Brown, November 2, 1971. Data about
paratypes (11) are presented in the appendix.

Diagnosis. - Genitalic characteristics must be used to reliably distinguish males of G. tectus
from those of G. germaini , G. chilenus , and G. clandestinus. Refer to the diagnosis of G.
germaini for further comments.

Description. — Form: Ovate, moderately convex (Fig. 83A). Size: Holotype 1.60 mm long, 0.76 mm wide. Color:
Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.32 mm; width 0.44 mm. Frons finely sparsely
punctate, microreticulate laterally, very sparsely pubescent; interocular foveae deep and large, width of each nearly 0.66
distance between them; interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture evenly arcuate.
Clypeus length 0.50 width, finely, moderately sparsely punctate, sparsely pubescent. Labroclypeal suture straight. Labrum
length 0.33 width; finely sparsely punctate, sparsely pubescent; median emargination moderately developed; lobes
upturned. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of 3. Mentum width equal length,
shining, finely sparsely punctate; anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous.
Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near
anterior 0.33) 0.58 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae.
Lateral hyaline border extended posteriorly from near midlength of anterior lobe of lateral depressions, moderately
arcuate to posterior lobe, more markedly arcuate to posterior angles, very narrow around posterior margin. Anterior
margin of pronotum arcuate. Lateral depressions sparsely finely punctate; anterior lobe slightly wider than long, much
larger than posterior lobe, anterior extreme arcuate; posterior lobe angulate, angle nearly right. Pronotum moderately
constricted behind lateral depressions. Lateral fossulae deep, faintly microreticulate, inner margin abrupt, outer margin
well marked, posterior extreme tapered into lateral hyaline border. Pronotal disc shiny, slightly convex, moderately
densely, moderately finely punctate, sparsely pubescent. Median groove moderately deep, narrow, faintly microreticulate.
Anterior foveae oval, moderately deep, moderately small, width 0.50 distance between fovea and median groove. Posterior
foveae moderately deep, narrow, microreticulate, tapered from posterior to anterior, length four times width at base,
length twice that of anterior fovea. Posterolateral angles with very shallow impressions. Prosternum with median carina
ended at coxal cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra: Length 1.08 mm.
maximum width (near midlength) 0.76 mm. Disc flat, shiny, with six rows of round punctures between suture and humeri,

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each puncture with seta. Declivity beginning near posterior 0.33. Intervals flat, width equal puncture width. Interstices
between punctures 0.25 puncture length. Explanate margin moderately developed. Abdomen: Basal four sterna entirely
covered with hydrofuge pubescence. Sternum 5 with posterior arc of glabrous area with anterior limits near midlength
of segment in midline, near posterior angles laterally. Segment 6 shiny, sparsely pubescent. Apical segment shiny; setae
of submedian setal groups short. Legs: Moderately long and slender; ratio of hind leg length to abdominal length
2.0/1. 0. protarsomeres 1-3 without pads of suction setae. Genitalia: Male (Fig. 88B)(2 examined); female (Fig. 9H).

Natural History. - The holotype, allotype and one female paratype were in a series with one
specimen of G. germaini and 28 specimens of G. clandestinus.

Distribution. - (Figs. 876,177). Chile.

Etymology. - Latin, tectus (secret, disguised). I refer to the marked similarity in external
features of adults of G. tectus , G. germaini , G. chilenus , and G. clandestinus.

8. Gymnochthebius curvus new species
(Figs. 9F,85B,86A,87A,177)

Type-locality. - 8 mi. E. of Rio Bueno, Valdivia Province, Chile.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in CAS. Paratypes with same data are in USNM (4) and PDP (2). These specimens were
collected by Ross and Michelbacher, January 15, 1951. One paratype, collected by P. and
P.Spangler in Orsorno Province, 8 km. S. of Orsorno, June 4, 1969, is deposited in USNM.

Diagnosis. - Relatively convex pronotal reliefs and aedeagal form (Figs. 8 5 B, 86 A) serve as
diagnostic characteristics for G. curvus.

Description. — Form: Ovate, moderately convex (Fig. 83A). Size: Holotype 1.76 mm long, 0.80 mm wide. Color:
Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.34 mm; width 0.46 mm. Frons finely sparsely
punctate, very sparsely pubescent; interocular foveae deep and large, width of each nearly 0.66 distance between them;
interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width,
finely sparsely punctate, sparsely pubescent, microreticulate laterally. Labroclypeal suture straight. Labrum length 0.33
width; finely sparsely punctate, sparsely pubescent; median emargination slightly developed, edge upturned apparently
with low rounded tooth in habitus view. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of 3.
Mentum width equal length, shining, finely sparsely punctate; anterior margin arcuate. Submentum evenly, finely
punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline
0.40 mm; maximum width (near anterior 0.33) 0.64 mm. Anterior hyaline border moderately wide in front of disc, slightly
wider in front of lateral fossulae. Lateral hyaline border extended posteriorly from near midlength of anterior lobe of
lateral depressions, moderately arcuate to posterior lobe, more markedly arcuate to posterior angles, very narrow around
posterior margin. Anterior margin of pronotum arcuate. Lateral depressions nearly impunctate; anterior lobe length equal
width, much larger than posterior lobe, anterior extreme arcuate; posterior lobe angulate, angle nearly right. Pronotum
moderately constricted behind lateral depressions. Lateral fossulae deep, faintly microreticulate, inner margin abrupt,
posterior extreme tapered into lateral hyaline border. Pronotal disc shiny, moderately convex, finely, sparsely punctate,
sparsely pubescent, areas between foveae slightly inflated. Median groove moderately deep, narroy, slightly constricted in
midregion, extremely faintly microreticulate. Anterior foveae oval, deep, width slightly greater than distance separating
fovea and median groove. Posterior foveae deep, tapered from posterior to anterior, length three times greatest width,
length twice that of anterior fovea, extremely faintly microreticulate. Posterolateral angles with very shallow impressions.
Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median glabrous area.
Elytra: Length 1.16 mm; maximum width (near midlength) 0.80 mm. Disc flat, shiny, with six rows of round punctures
between suture and humeri, each puncture with seta. Declivity beginning near posterior 0.33. Intervals flat, width slightly
greater than puncture width; interstices between punctures 0.25 puncture length. Explanate margin moderately developed.
Abdomen: Basal four sterna entirely covered with hydrofuge pubescence. Sternum 5 pubescent in anterior 0.50, posterior
0.50 glabrous. Segment 6 shiny, sparsely pubescent. Apical segment shiny; setae of submedian setal groups moderately
short. Legs: All legs moderately long and slender; ratio of hind leg length to abdominal length 1. 7:1.0. Protarsomeres 1-3
without suction setae. Genitalia: Male (Fig. 85B)(8 examined); female (Fig. 9F).

Distribution. - (Figs. 87A,177). Southern Chile.

Etymology. - Latin, curvus (curved). This is a reference to the two most distinctive features
of adults of this species, the markedly arcuate internal tube of the aedeagus and the convex
pronotal reliefs.

Western Hemisphere Hydraenidae 263

Figs. 85A - D, Aedeagi of Gymnochthebius species. (A) G. germaini, variant. (B) G. curvus, holotype. (C) G. germaini.
(D) G. germaini , aedeagus with internal tube protruded (parameres omitted).

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9. Gymnochthebius bisagittatus new species
(Figs. 83E,95B, 177)

Type-locality. - 12 km. S. Tocancipa, Cundinamarca Department, Columbia.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. Paratypes with same data are in USNM (10) and PDP (4). One additional
paratype, with the following data, is also deposited in USNM: Bogota?, 6-9-36, L.M. Morillo.

Diagnosis. - Pronotal form, especially shape of anterior lobes (Fig. 83E) plus male genitalic
characteristics serve to distinguish this species.

Description. — Form: Ovate, moderately convex (Fig. 83E). Size: Holotype 1.88 mm long, 0.84 mm wide. Color:
Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.36 mm; width 0.50 mm. Frons finely sparsely
punctate, very sparsely pubescent, interocular foveae deep and large, width of each nearly 0.66 distance between them;
interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width,
moderately coarsely, moderately densely punctate, sparsely pubescent. Labroclypeal suture straight. Labrum length 0.33
width; finely sparsely punctate, sparsely pubescent; median emargination slightly developed, edge upturned; evenly
rounded in habitus view. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 slightly less than 0.50 length of
penultimate. Mentum width equal length, shining, finely sparsely punctate; anterior margin arcuate. Submentum evenly,
finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at
midline 0.44 mm; maximum width (near anterior 0.33) 0.64 mm. Anterior hyaline border moderately wide in front of disc,
slightly wider in front of lateral fossulae. Lateral hyaline border extended posteriorly from base of anterior lobe of lateral
depressions, slightly arcuate to posterior angles, very narrow around posterior margin. Anterior margin of pronotum
slightly arcuate. Lateral depressions deflexed, nearly impunctate; anterior lobe much wider than long, larger than posterior
lobe, anterior extreme slightly arcuate; posterior lobe in form of small tooth. Pronotum moderately constricted behind
lateral depressions. Lateral fossulae deep, inner margin abrupt, outer margin well demarcated, posterior extreme tapered
into lateral hyaline border. Pronotal disc shiny, slightly convex, finely, sparsely punctate, sparsely pubescent. Median
goove narrow, shallow, faintly microreticulate. Anterior foveae oval, deep, width equal distance between fovea and median
groove. Posterior foveae deep, length three times width, length twice that of anterior fovea, extremely faintly
microreticulate. Posterolateral angles lacking shallow impressions. Prosternum with median carina ending at coxal
cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra: Length 1.24 mm; maximum width (near
midlength)0.84 mm. Disc flat, shiny, with six rows of round punctures between suture and humeri, each puncture with
seta. Declivity origin near posterior 0.33. Intervals rounded, width equal to puncture width. Interstices between punctures
0.25 puncture length. Explanate margin moderately developed. Abdomen: Basal four sterna entirely covered with
hydrofuge pubescence. Sternum 5 with posterior arc of glabrous area with anterior limits near midlength of segment in
midline, near posterior angles laterally. Segment 6 shiny, sparsely pubescent. Apical segment shiny; setae randomly
placed, not in form of discrete submedian rows. Legs: All legs moderately long and slender; ratio of hind leg length to
abdominal length 1.8: 1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 95B)(4 examined).

Distribution. - (Fig. 177). Known only from two localities near Bogota, Colombia.

Etymology. - Latin, bi (two) plus sagittatus (arrow). This is a reference to shape of anterior
lobes of the lateral pronotal depressions, which are reminiscent of broadly rounded,
asymmetrical arrowheads.

10. Gymnochthebius francki (Bruch)

(Figs. 86C-E,177)

Ochthebius francki Bruch, 1915:464. (lectotype male in ISNB, here designated; type-locality: Parque Saavedra, Buenos
Aires, Argentina):

Diagnosis. - Very finely and sparsely punctate pronotum, testaceous elytra, moderately
deeply impressed elytral striae, and aedeagal form are the distinctive features of G. francki.
Adults with pronotal form and sculpture most closely similar to those of G. francki is G.
bisagittatus. Adults of the latter species, however, are uniformly dark brown and have the
pronotum shaped slightly differently, especially the anterior lobes (Figs. 83E,86C). G. francki
is known only from Argentina, whereas G. bisagittatus ia presently known only from Colombia.

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Description. — Form: Ovate, moderately convex (Fig. 86C). Size: Lectotype 1.88 mm long, 0.83 mm wide. Color:
Head dark brown; pronotum and venter brown; elytra, legs, palpi, antennae and elytral epipleura testaceous. Head: Length
0.30 mm; width 0.44 mm. Frons finely sparsely punctate, very sparsely pubescent; interocular foveae deep and large, width
of each nearly 0.66 distance between them; interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture
evenly arcuate. Clypeus length 0.50 width, finely sparsely punctate, sparsely pubescent, faintly microreticulate laterally.
Labroclypeal suture straight. Labrum length 0.33 width; finely sparsely punctate, sparsely pubescent; median
emargination slightly developed, edge upturned; evenly rounded in habitus view. Maxillary palpus with palpomere 3
moderately wide; palpomere 4 nearly 0.66 length of 3. Mentum width equal length, shining, finely sparsely punctate;
anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.42 mm; maximum width (near anterior 0.33) 0.58 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae. Lateral hyaline border extended
posteriorly from near midlength of anterior lobe of lateral depressions, straight to posterior angles, very narrow around
posterior margin. Anterior margin of pronotum slightly arcuate. Lateral depressions deflexed; nearly impunctate;
indentation slight between anterior and posterior lobes; anterior lobe much wider than long, much larger than posterior
lobe, anterior extreme arcuate and prominently pubescent; posterior lobe angulate, angle nearly right. Pronotum
moderately constricted behind lateral depressions. Lateral fossulae deep, extremely faintly microreticulate, inner margin
abrupt, outer margin well marked, posterior extreme tapered into lateral hyaline border. Pronotal disc shiny, very slightly
convex, extremely finely, extremely sparsely punctate, sparsely pubescent. Median groove moderately deep, moderately
wide, extremely faintly microreticulate. Anterior foveae oval, deep, width equal distance between fovea and median
groove. Posterior foveae deep, length three times width, length slightly greaer than twice that of anterior fovea, faintly
microreticulate. Posterolateral angles without shallow impressions. Prosternum with median carina ended at coxal cavities;
coxae contiguous. Metasternum with large median glabrous area. Elytra: Length 1.16 mm; maximum width (near
midlength) 0.83 mm. Disc flat, shiny, with six rows of large round punctures between suture and humeri, each puncture
with seta. Declivity origin near posterior 0.33. Intervals rounded, slightly elevated, width slightly less than puncture width;
interstices between punctures 0.25 puncture length. Explanate margin moderately developed. Abdomen: Basal four sterna
entirely covered with hydrofuge pubescence. Sternum 5 with posterior arc of glabrous area whose anterior limits are near
midlength of segment in midline, near posterior angles laterally. Segment 6 shiny, sparsely pubescent. Apical segment
shiny; setae of submedian setal groups moderately short. Legs: Moderately long and slender; ratio of hind leg length to
abdominal length 1.8: 1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male (Figs. 86D,E)(2 examined).

Variation. - The single male from Salta is considerably smaller than the lectotype, being
1.68 mm long and 0.80 mm wide. External form and sculpture of this specimen does not differ
detectably from that of the lectotype, and the aedeagus (Figs. 86D,E) does not differ
significantly. Males of this species are easily discerned, the labrum being upturned along the
entire anterior margin which, when seen in habitus view, obscures the small median
emargination and results in the anterior edge appearing evenly arcuate. Females have the
labrum rather deeply emarginate and lack the markedly upturned margin.

Distribution. - (Fig. 177). Presently known from Buenos Aires (lectotype) and from Salta,
Salta Province, Argentina (2 specimens).

11. Gymnochthebius topali (J. Balfour-Browne)

(Figs. 9B,80D,84D,90B,177)

Ochthebius topali J. Balfour-Browne, 1971:181 (holotype male in HNHM; type-locality: Rio Negro, El Bolson,

Argentina).

Diagnosis. - The small pronotum with its slender anterior lobes and very finely
microreticulate reliefs, together with the rather deeply emarginate labrum make adults of this
species distinctive amongst the group with sternum five partially pubescent (Fig. 80D).

Description. — Form: Ovate, moderately convex (Fig. 80D). Size: Holotype 1.76 mm long, 0.76 mm wide. Color:
Dorsum black; venter dark brown; legs and palpi brown. Head: Length 0.36 mm; width 0.44 mm. Eyes large. Frons finely
sparsely punctate, very sparsely pubescent, finely microreticulate; interocular foveae deep and large, width of each nearly
0.50 distance between them; interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture markedly
arcuate. Clypeus length 0.50 width, finely sparsely punctate, sparsely pubescent, microreticulate laterally. Labroclypeal
suture straight. Labrum length 0.33 width; densely pubescent, especially near borders; median emargination markedly
developed, depth 0.33 length of labrum, edge slightly upturned; lobes formed by median emargination at slight angle to
remainder of labrum. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 slightly less than 0.50 length of 3.
Mentum width equal length, shining, finely sparsely punctate; anterior margin arcuate. Submentum evenly, finely

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punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at
midline 0.36 mm; maximum width (near anterior 0.33) 0.56 mm. Anterior hyaline border moderately wide in front of
disc, wider in front of lateral depressions. Lateral hyaline border origin near anterior 0.33 of anterior lobe of lateral
depressions, moderately arcuate to posterior lobe, more markedly arcuate to posterior angles, very narrow around
posterior margin. Anterior margin of pronotum slightly arcuate. Lateral depressions very finely microreticulate; anterior
lobe slightly longer than wide, much larger than posterior lobe, anterior extreme arcuate; posterior lobe angulate, angle
nearly right, apex of angle with prominent tooth. Pronotum moderately constricted behind lateral depressions. Lateral
fossulae finely microreticulate, moderately deep, inner margin abrupt, posterior extreme extended to lateral hyaline
border. Pronotal disc dull, slightly convex, finely, sparsely punctate, finely microreticulate, sparsely pubescent. Median
groove moderately deep, moderately wide, microreticulate. Anterior foveae circular, deep, moderately small, width equal
distance between fovea and median groove. Posterior foveae deep, length twice width, length twice that of anterior
fovea, microreticulate. Posterolateral angles with very shallow impressions. Prosternum with median carina ended at
coxal cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra: Length 1.08 mm; maximum
width (near midlength) 0.76 mm. Disc flat, shiny with six rows of deep, round punctures between suture and humeri,
each puncture with seta. Declivity origin near posterior 0.33. Intervals rounded, width 0.33 puncture width; interstices
between punctures 0.25 puncture length; explanate margin moderately developed. Abdomen: Basal four sterna entirely
covered with hydrofuge pubescence. Sternum 5 with posterior arc of glabrous area with anterior limits near midlength
of segment in midline, near posterior angles laterally. Segment 6 shiny, sparsely pubescent. Apical segment shiny; setae
of submedian setal group of moderate length. Legs: Moderately long and slender; ratio of hind leg length to abdominal
length 1.7: 1.0. Protarsomeres 1-3 without pad of suction setae. Genitalia: Male (Fig. 84D)(5 examined); female
(Fig. 9B)

Variation. - Pronota of many Chilean specimens are more finely microreticulate and have
more slender anterior lobes than specimens from Argentina.

Natural History. - J. Balfour-Browne (1971) reports that adults of the large paratype series
(149 specimens) were “singled from under stones and mud near stagnant water of Rio
Quemquemtrei”.

Distribution. - (Figs. 90B,177). Andes mountains of southern Argentina and Chile. I have
examined 18 specimens (see appendix).

Remarks. - The aedeagus I have illustrated is from a specimen collected in Chile, Negrete,
Bio-Bio. It compares very closely with the holotype, which I have studied.

12. Gymnochthebius compactus new species
(Figs. 9D,80F,177)

Type-locality. - Curitiba, Parana State, Brazil.

Type-specimen. - The holotype female (unique) is deposited in USNM. Paul and Phyllis
Spangler collected this specimen, June 28, 1969.

Diagnosis. - Truncate, convex body form, large, deep pronotal foveae, deep elytral
punctures, and subcostate elytral intervals serve to characterize adults of this distinctive species
(Fig. 80F).

Description. — Form: Convex, ovate (Fig. 80F). Size: Holotype 1.60 mm long, 0.80 mm wide. Color: Dorsum and
venter dark brown; legs and palpi brown. Head: Length 0.36 mm; width 0.46 mm. Frons finely sparsely punctate, very
sparsely pubescent; interocular foveae deep and large, width of each nearly 0.66 distance separating them; interocular
tuberculi large; basomedial fovea transverse. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width, finely
sparsely punctate, sparsely pubescent, faintly microreticulate basally and laterally. Labroclypeal suture straight. Labrum
length 0.50 width; finely sparsely punctate, sparsely pubescent; anterior margin straight, extremely slightly upturned in
midregion. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of 3. Mentum width equal
length, shining, finely sparsely punctate; anterior margin arcuate. Submentum evenly, finely punctulate, punctures
contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum
width (near anterior 0.33) 0.68 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in front of
lateral fossulae. Lateral hyaline border origin near midlength of anterior lobe of lateral depressions, moderately arcuate to
posterior angles, very narrow around posterior margin. Anterior margin of pronotum arcuate. Lateral depressions nearly
impunctate; anterior lobe width equal length, larger than posterior lobe, anterior extreme arcuate; posterior lobe angulate,
angle nearly right. Pronotum moderately constricted behind lateral depressions. Lateral fossulae deep, microreticulate,
inner margin abrupt, outer margin well demarcated, posterior extreme extended to lateral hyaline border. Pronotal disc

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shiny, strongly convex, extremely finely, extremely sparsely punctate, sparsely pubescent, areas between median groove
and foveae inflated. Median groove narrow, moderately deep, slightly constricted in midregion, faintly microreticulate.
Anterior foveae oval, very deep, width equal distance between fovea and median groove. Posterior foveae deep, length
three times width, length twice that of anterior fovea, extremely faintly microreticulate. Posterolateral angles with very
shallow impressions. Prosternum with median carina ending at coxal cavities; coxae contiguous. Metasternum with large
median glabrous area. Elytra: Length 1.08 mm; maximum width (near midlength) 0.80 mm. Disc convex, shiny, with
six rows of round punctures between suture and humeri, each puncture with seta. Declivity origin near midlength of
elytra. Intervals rounded, slightly elevated, width equal puncture width. Interstices between punctures 0.25 puncture
length. Explanate margin moderately developed. Abdomen: Basal four sterna entirely covered with hydrofuge
pubescence. Sternum 5 glabrous in apical 0.66. Sternum 6 shiny, sparsely pubescent. Legs: All legs moderately short
and stout; ratio of hind leg length to abdominal length 1.6: 1.0. Protarsomeres 1-3 without suction setae. Genitalia:
Female (Fig. 9D)(1 examined); male unknown.

Distribution. - (Fig. 177). Known only from the type-locality.

Etymology. - Latin, compactus (compact). This is a reference to the body form.

13. Gymnochthebius peruvianus (J. Balfour-Browne)

(Figs. 50A,84C,86B,177)

Ochthebius peruvianus J. Balfour-Browne, 1971:182 (holotype male in BMNH; type-locality: Villa (cerca Lima), Peru).

Diagnosis. - Coarsely puncate pronotum, deeply impressed elytral striae and pale elytral
coloration serve as diagnostic characteristics for adults of this distinctive species (Fig. 86B).

Description. — Form: Ovate, moderately convex (Fig. 86D). Size: Holotype 1.68 mm long, 0.80 mm wide. Color:
Head, pronotum and venter dark brown; elytron testaceous except for illdefined dark band extended nearly entire length in
midregion; legs, palpi and elytral epipleura testaceous. Head: Length 0.32 mm; width 0.44 mm. Frons coarsely, densely
punctate, very sparsely pubescent; interocular foveae deep and large, width of each nearly 0.66 distance between them;
interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width,
coarsely densely punctate, sparsely pubescent, microreticulate laterally. Labroclypeal suture straight. Labrum length 0.33
width; finely sparsely punctate, sparsely pubescent; median emargination weakly developed, edge upturned; evenly
rounded in habitus view. Maxillary palpus with palpomere 3 moderately wide; ultimate segment slightly greater than 0.50
length of penultimate. Mentum width equal length, shining, finely sparsely punctate; anterior margin arcuate. Submentum
evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum
length at midline 0.40 mm; maximum width (near anterior 0.33) 0.60 mm. Anterior hyaline border moderately wide in
front of disc, slightly wider in front of lateral fossulae. Lateral hyaline border origin near midlength of anterior lobe of
lateral depressions, moderately arcuate to posterior lobe, more markedly arcuate to posterior angles, very narrow around
posterior margin. Anterior margin of pronotum arcuate. Lateral depressions coarsely punctate; anterior lobe wider than
long, much larger than posterior lobe, anterior extreme arcuate; posterior lobe angulate, angle nearly right, small tooth at
apex. Pronotum moderately constricted behind lateral depressions. Lateral fossulae deep, very faintly microreticulate and
punctate, inner margin abrupt, posterior extreme tapered into lateral hyaline border. Pronotal disc shiny, slightly convex,
coarsely densely punctate, sparsely pubescent. Median groove moderately deep, narrow, outline somewhat irregular, with
large punctures. Anterior foveae faintly microreticulate, circular, deep, width equal distance between fovea and median
groove, outline somewhat irregular, large punctures at periphery. Posterior foveae deep, length twice width, length twice
that of anterior fovea, outline irregular, large punctures at periphery. Posterolateral angles with very shallow impressions.
Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median glabrous area.
Elytra: Length 1.08 mm; maximum width (near midlength)0.80 mm. Disc flat, shiny, with 6 striate rows of large round
punctures between suture and humeri, each puncture with seta. Declivity origin near posterior 0.33. Intervals rounded,
slightly elevated, width slightly less than puncture length. Explanate margin moderately developed. Abdomen: Basal four
sterna entirely covered with hydrofuge pubescence. Segment 5 pubescent in anterior 0.50, posterior 0.50 glabrous.
Segment 6 shiny, sparsely pubescent. Apical segment shiny; setae of submedian setal groups short. Legs: All legs
moderately long and slender; ratio of hind leg length to abdominal length 1.7: 1.0 Protarsomeres 1-3 without suction setae.
Genitalia: Male (Fig. 84C)(2 examined).

Distribution. - (Figs. 50A,177). Known only from the type-locality near Lima and from 10
km. S. of Chiclayo, Lambayeque Department, Peru.

Remarks. - My measurements of the holotype are less than those indicated by
J. Balfour-Browne (1971) (1.68 x 0.80 vs. 1.85 x 0.87). I have not seen the two female
paratypes he designated.

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Figs. 87A - B, Geographical distributions. (A) Gymnochthebius germaini ®, G. chilenus ★ and G. curvus A- (B)
Gymnochthebius clandestinus • , G. tectus ★ and Meropathus vectis A •

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14. Gymnochthebius bartyrae new species
(Figs. 9C,50A,80B,95A,177)

Type-locality. - Rio Blanco, Quebrada Copa, Lima Department, Peru.

Type-specimens. - Holotype male and allotype, with identical locality data, are deposited in
MSP. Hans and Bartyra Reichardt collected these specimens, together with three paratypes (1
USNM; 2 PDP), November 1, 1974. One paratype, with the following data, is deposited in
CAS: 5 mi. NE Cerro de Pasco, 3,500 meters, 29-12-54, Schlinger and Ross.

Diagnosis. - The shiny, mottled elytra and unusual pronotal form (Fig. 80B) of adults make
G. bartyrae one of the most distinctive members of the germaini Group. The pronotal disc is
quite convex, contrasting remarkably with the very flat, broad lateral depressions. The pronotal
foveae and median groove are large, deeply impressed and markedly microreticulate. The sides
of the pronotum are rather markedly convergent to the base, giving the pronotum a
subtriangular appearance.

Description. — Form: Moderately elongate; rather convex transversely, only moderately convex longitudinally
(Fig. 80B). Size: Holotype 1.84 mm long, 0.80 mm wide. Color: Head, pronotum and venter dark brown; elytra with dark
and light brown mottlings; legs and palpi brown. Head: Length 0.36 mm; width 0.46 mm. Frons markedly microreticulate
over entire surface, very sparsely pubescent; interocular foveae deep and large, width of each nearly equal to distance
between them; interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture evenly arcuate. Clypeus
length 0.50 width, markedly microreticulate. Labroclypeal suture straight. Labrum length 0.33 width; markedly
microreticulate, sparsely pubescent; median emargination moderately developed; lobes upturned very slightly. Maxillary
palpus with palpomere 3 moderately wide; palpomere 4 slightly less an 0.50 length of penultimate. Mentum width equal
length, shining, finely sparsely punctate; anterior margin arcuate. Submentum evenly, finely punctulate, punctures
contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.42 mm; maximum
width (near anterior angles) 0.58 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in front of
lateral fossulae. Lateral hyaline border origin near midlength of anterior lobe of lateral depressions, extended straight to
posterior angles, very narrow around posterior margin. Anterior margin of pronotum arcuate. Lateral depressions flat,
markedly microreticulate; anterior lobe slightly developed, much wider than long, larger than posterior lobe, anterior
extreme arcuate; posterior lobe ngulate, angle nearly right. Pronotum moderately constricted behind lateral depressions.
Lateral fossulae deep, inner margin vertical, outer margin indistinguishable from remainder of lateral depression. Pronotal
disc very convex, dull, markedly microreticulate except small area between anterior and posterior foveae of a side; areas
between median groove and foveae inflated. Median groove deep and wide, especially in anterior 0.50, latter twice width of
posterior 0.50, markedly microreticulate. Anterior foveae oval, deep, microreticulate, width equal distance between fovea
and median groove. Posterior foveae very deep, length twice width, length twice that of anterior fovea, markedly
microreticulate. Posterolateral angles lacking shallow impressions. Prosternum with median carina ended at coxal cavities;
coxae contiguous. Metasternum with very large median glabrous area. Elytra: Length 1.20 mm. maximum width (near
midlength) 0.80 mm. Disc flat, depression in midregion, shiny, with six rows of small round punctures between suture and
humeri, each puncture with seta. Declivity origin near posterior 0.33. Intervals flat, width three times puncture width.
Interstices between punctures equal to puncture length. Explanate margin moderately developed. Abdomen: Basal four
sterna covered with hydrofuge pubescence. Sternum 5 with posterior arc of glabrous area with anterior limits near anterior
0.33 of segment in midline, near posterior angles laterally. Segment 6 shiny, sparsely pubescent. Apical segment shiny;
setae of submedian setal groups short. Legs: Moderately long and slender; ratio of hind leg length to abdominal length
1. 8:1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 95A)(2 examined); female (Fig. 9C).

Natural History. - Hans Reichardt wrote (in litt.) that the holotype and its series were
“collected in a more or less hygropetric habitat, in cold water”, on km 103 of the Carretera
Central, at an elevation of 3,400 meters.

Distribution. - (Figs. 50A,177). Known only from two localities near Lima, Peru.

Etymology. - I am pleased to acknowledge the request of the late Hans Reichardt, and
dedicate this new species to his wife, Bartyra.

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The reticulatus Subgroup

Adults of the reticulatus Subgroup are characterized by very well developed dorsal
microreticulation, large size and convex body form. The aedeagus is straight and nearly
symmetrical in dorsal view, with the parameres dorsal to the median portion, not at the sides.

Only two rather closely related species are currently known for this subgroup.

15. Gymnochthebius reticulatus (d’Orchymont)

(Figs. 80C,88A,90B)

Ochthebius reticulatus d’Orchymont, 1943:45 (holotype male deposited in 1SNB; type-locality: Hornadita, Jujuy

Province, Argentina).

Diagnosis. - Large size, convey form and microreticulate pronotum (Fig. 80C) readily
distinguish adults of this species from those of others in the subgenus which likewise have
sternum 5 partially hydrofuge pubescent and the metasternum with a large glabrous area,
except G. reticulatissimus. Adults differ from those of the latter in having: 1) elytra striate
with intervals rounded instead of costate; 2) dorsal microreticulation less developed, especially
on elytra and pronotal disc, the former quite shiny and the latter slightly shiny relative to the
more markedly microreticulate remainder of the pronotum; 3) punctation of the pronotum and
head less well developed, especially evident on the shiny, non-microreticulate area on the
clypeus; 4) the anterior lobes of the pronotum more prominent; and 5) different aedeagal form
(Figs. 88A,C).

Description. — Form: Broadly ovate, very convex (Fig. 80C). Size: Holotype 2.08 mm long, 0.98 mm wide. Color:
Brown, head slightly darker; pronotum with faint metallic reflections. Head: Length 0.40 mm; width 0.54 mm. Frons
markedly microreticulate, finely sparsely punctate, very sparsely pubescent; interocular foveae moderately deep and large,
width of each nearly 0.50 distance between them; interocular tuberculi small; basomedial fovea transverse. Frontoclypeal
suture evenly arcuate. Clypeus length 0.50 width, width, finely sparsely punctate; sides and basal 0.50 microreticulate and
dull, remainder shiny and non- microreticulate. Labroclypeal suture straight. Labrum length 0.33 width; densely,
moderately coarsely punctate, sparsely pubescent; median emargination well developed; lobes upturned, at angle to
remainder of labrum. Maxillary palpus with penultimate 3 moderately wide; palpomere 4 0.50 length of 3. Mentum width
equal length, shining, moderately densely punctate; anterior margin arcuate. Submentum evenly, finely punctulate,
punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.48 mm;
maximum width (near anterior 0.33) 0.76 mm. Anterior hyaline border narrow in front of disc, slightly wider in front of
lateral fossulae. Lateral hyaline border wide, origin near base of anterior lobe, more markedly arcuate to posterior angles,
very narrow around posterior margin. Anterior margin of pronotum straight in midregion. Lateral depressions markedly
microreticulate, without apparent punctation; anterior lobe well produced, acute at apex, tapered gradually into posterior
lobe; posterior lobe with small tooth at apex. Pronotum moderately constricted behind lateral depressions. Lateral fossulae
deep, markedly microreticulate; inner margin abrupt, outer margin ill-defined. Pronotal disc microreticulate, but effacedly
so, distinctly more reflective than remainder of pronotum, convex, finely sparsely punctate, non-pubescent. Median groove
deep, moderately wide, slightly constricted in midregion, markedly microreticulate. Anterior foveae very deep, oval, width
equal distance between fovea and median groove, markedly microreticulate. Posterior foveae moderately deep, length three
times width, length twice that of anterior foveae, markedly microreticulate. Posterolateral angles with distinct impressions.
Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median glabrous area.
Elytra: Length 1.36 mm; maximum width (near midlength)0.98 mm. Disc convex, shiny, with six rows of punctures in
shallow furrows between suture and humeri. Declivity origin near posterior 0.33. Intervals rounded, not costate, width
slightly greater than puncture width, with very fine impressions. Interstices between punctures reduced to narrow walls.
Explanate margin well developed. Abdomen: Basal four sterna entirely covered with hydrofuge pubescence. Sternum 5
with posterior arc of grabrous area with anterior limits near midlength of segment in midline, near posterior angles
laterally. Segment 6 shiny, sparsely pubescent. Apical segment shiny, sparsely pubescent, hairs not in discrete groups.
Legs: Moderately long and slender; ratio of hind leg length to abdominal length 1 .8:1 .0. Protarsomeres 1-3 without suction
setae. Genitalia: Male (Fig. 88A)(1 examined); female unknown.

Natural History. - The holotype and paratype were collected at 3,400 and 3,700 meters,
respectively. Nothing else is known of the habitat.

Quaest. Ent., 1980, 16 (1,2)

Figs. 88A - C, Aedeagi of Gymnochthebius holotypes. (A) G. reticulatus. (B) G. tectus. (C) G. reticulatissimus.

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273

Distribution. - (Fig. 90B). Presently known only from the type- locality in Argentina and
by one male paratype, which I have not seen, from Cueva Iturbe in the same province
(d’Orchymont, 1943).

Remarks. - The aedeagus of the holotype (Fig. 8 8 A) appears to lack the internal tube
characteristic of other Gymnochthebius males. Indeed, the marked development of the internal
tube of males of G. reticulatissimus (Fig. 88C), the sister-species of reticulatus, leads me to
suspect that perhaps the internal tube of the holotype was inadvertently pulled from the
aedeagus proper during dissection, which was performed by a previous worker. Confirmation of
the internal aedeagal form must await availability of additional specimens.

16. Gymnochthebius reticulatissimus new species
(Figs. 80A,88C,90B)

Type-locality. - 15 km. W. Tucuman, Tucuman, Argentina.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. These specimens, presently the only known, were collected by Paul and Phyllis
Spangler, May 22, 1969.

Diagnosis. - Among those species in the subgenus Gymnochthebius characterized by
sternum 5 partially hydrofuge pubescent and the metasternum with a median glabrous area,
adults of G. reticulatissimus are distinguished by large, convex form, coarsely microreticulate
dorsum, costate elytral intervals and pronotal form (Fig. 80 A). From adults of its putative
sister-species, G. reticulatus , adults of G. reticulatissimus differ in possession of costate elytral
intervals, more markedly developed punctation of the pronotum, head and dorsal
microreticulation in general, and aedeagal form (Figs. 88 A, C). Refer to the diagnosis of G.
reticulatus for further comments.

Description. — Form: Broadly ovate, very convex (Fig. 80A). Size: Holotype 2.12 mm long, 1.08 mm wide. Color:
Brown; pronotum with faint gold-green iridescence. Head: Length 0.48 mm; width 0.58 mm. Frons markedly
microreticulate, finely sparsely punctate, very sparsely pubescent; interocular foveae moderately deep and large, width of
each nearly 0.50 distance between them; interocular tuberculi indistinct; basomedial fovea transverse. Frontoclypeal suture
evenly arcuate. Clypeus length 0.50 width, finely, moderately densely punctate; anterior 0.50 shiny, without
microreticulation; posterior 0.50 dull, with well developed microreticulation; very sparsely pubescent. Labroclypeal suture
straight. Labrum length 0.33 width; densely, moderately coarsely punctate, sparsely pubescent; median emargination well
developed; lobes upturned, at angle to remainder of labrum. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4 0.25 length of 3. Mentum width equal length, shining, densely, coarsely punctate; anterior margin arcuate.
Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax:
Pronotum length at midline 0.50 mm; maximum width (near anterior 0.33) 0.80 mm. Anterior hyaline border narrow in
front of disc, slightly wider in front of lateral fossulae. Lateral hyaline border wide, origin at small tooth near base of
anterior lobe of lateral depressions, moderately arcuate to posterior lobe, more markedly arcuate *to posterior angles, very
narrow around posterior margin. Anterior margin of pronotum straight in midregion. Lateral depressions markedly
microreticulate, densely, moderately coarsely punctate; anterior lobe wider than long, much larger than posterior lobe,
anterior extreme arcuate; posterior lobe angulate, angle nearly right, with small tooth at apex. Pronotum moderately
constricted behind lateral depressions. Lateral fossulae deep, markedly microreticulate, inner margin abrupt, outer margin
illdefined, posterior extreme extended to lateral hyaline border. Pronotal disc dull, strongly microreticulate, convex, finely,
moderately densely punctate, non-pubescent. Median groove deep, moderately wide, slightly constricted in midregion,
markedly microreticulate. Anterior foveae deep, oval, width slightly less than distance between fovea and median groove,
markedly microreticulate. Posterior foveae deep, length three times width, length twice that of anterior fovea, markedly
microreticulate. Posterolateral angles with deep impressions. Prosternum with median carina ended at coxal cavities; coxae
contiguous. Metasternum with large median glabrous area densely, finely punctate. Elytra: Length 1 .42 mm; maximum
width (near midlength) 1 .08 mm. Disc convex, dull, with six rows of ill-defined punctures in deep furrows between suture
and humeri. Furrows markedly microreticulate. Declivity origin near posterior 0.33. Intervals costate, width slightly less
than furrow width, weakly microreticulate. Explanate margin well developed. Abdomen: Basal four sterna covered with
hydrofuge pubescence. Sternum 5 with posterior arc of glabrous area with anterior limits near midlength of segment in
midline, near posterior angles laterally. Segment 6 shiny, sparsely pubescent. Apical segment shiny; setae of submedian

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setal groups in patches, not in discrete rows. Legs: Moderately long and slender; ratio of hind leg length to abdominal
length 1.8: 1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 88C)( 1 examined).

Distribution. - Known only from the type-locality in Tucuman Province, Argentina.

Etymology. - Latin reticulatus (netlike) plus adjectival superlative issimus (most). Named
in reference to the very well developed dorsal microreticulation.

Remarks. - A notable morphological feature, which appears to be unique to this species, is
form of the anterior extremes of the lateral hyaline borders where they join the pronotum
proper. In this region the usually transparent borders are thickened and darkly colored to
produce a small, acute process on either side of the pronotum.

The nitidus Group

This group consists of moderate to small sized, generally smooth species which lack
hydrofuge pubescence on sternum 5. Adults of six of the species have a similar habitus, with
more or less well developed digitiform anterior lobes of the pronotum, but differ from one
another in various characters which are discussed in the keys and elsewhere. The remaining two
species form a discrete subunit by virtue of small, truncate appearance, costate or subcostate
elytra and in the form of the lateral pronotal depressions which have the posterior lobes larger
than the anterior. This is opposite the condition seen in the remainder of the genus. I feel,
however, that giving these two species, G. oppositus and G. seminole , separate formal
taxonomic status would not be useful at this time. G. fossatus has a remarkably extensive
distribution, ranging from southern United States to Argentina. The remaining species in the
group are not known outside the north-south boundaries of southern Canada and Costa Rica,
although I suspect some Central and South American species remain to be discovered.

The nitidus Subgroup

Members of this subgroup are characterized by presence of well developed rows of
punctures on the elytra. They have all four pronotal foveae, and the body is generally of
moderate size and convexity.

One species (G. fossatus) ranges from the United States south to Argentina. The other two
species currently known for the subgroup are represented in northeastern United States and
adjacent Canada (G. nitidus ), and southcentral United States ( G.falli ).

Habitat data suggest that these species are principally adapted to lotic habitats.

17. Gymnochthebius nitidus (LeConte)

(Figs. 89H,90A,93D,F,96B,179)

Ochthebius nitidus LeConte, 1850:217. (holotype female in MCZ; type-locality: Eagle Harbor, Keweenaw County,
Michigan). - LeConte, 1855:361. - LeConte,1878:378. - Horn, 1890:22. Blatchley, 1910:253. -

d’Orchymont,l 943:37.

Diagnosis. - Adults of this species are easily confused with those of two other members of
the nitidus Subgroup which have digitiform anterior lobes of the lateral depressions: G.
fossatus and G. falli. G. nitidus adults are more convex than are those of either of these two
species, especially the elytra. This difference is most striking between G. nitidus and G. falli ;

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275

Figs. 89A - H, Gymnochthebius body outlines. (A) G. maureenae. (B) G. perlabidus. (C) G. laevipennis. (D) G. seminole.
(E) G. oppositus. (F) G.falli. (G) G.fossatus. (FI) G. nitidus.

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the latter are also larger (males ca. 1.70 mm vs. 1.24 mm), with narrower hyaline border, and
generally have lighter colored elytra which contrast with the darker pronotum, whereas G.
nitidus adults are uniformly dark brown. These size and color differences do not occur
constantly between G. nitidus and G. fossatus, however. Their allopatric distributions will be
an aid in making determinations: G. nitidus is a temperate species, found in Canada and
northeastern United states; G. fossatus is essentially a tropical species, its distribution ranging
from southern United States to Central and South America. For further comment on these
three species, refer to the diagnoses of G.falli and G. fossatus.

Description. — Form: Moderately convex, ovate (Fig. 89H). Size: Holotype 1.24 mm long, 0.72 mm wide. Head:
Length 0.28 mm; width 0.40 mm Frons finely sparsely punctate, very sparsely pubescent; interocular foveae deep and
large, width of each nearly 0.66 distance between them; interocular tuberculi large; basomedial fovea transverse.
Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width, extremely finely microreticulate, sparsely pubescent.
Labroclypeal suture straight. Labrum length 0.33 width; finely sparsely punctate, sparsely pubescent; median
emargination weakly developed. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.66 length of 3.
Mentum width equal length, shining, finely sparsely punctate; anterior margin arcuate. Submentum evenly, finely
punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum (Fig. 96B)
length at midline 0.36 mm; maximum width (near anterior 0.33) 0.60 mm. Anterior hyaline border moderately wide in
front of disc, slightly wider in front of lateral fossulae. Lateral hyaline border very wide, origin near apex of anterior lobe
of lateral depressions, moderately arcuate to posterior lobe, moderately arcuate to posterior angles, very narrow around
posterior margin. Anterior margin of pronotum slightly arcuate in midregion. Lateral depressions nearly impunctate;
anterior lobe slightly longer than wide, distinctly larger than posterior lobe, anterior extreme arcuate; posterior lobe
angulate, angle nearly right. Pronotum moderately constricted behind lateral depressions. Lateral fossulae deep, oval,
length equal distance from posterior margin of fossula to margin of pronotum. Pronotal disc shiny, convex, extremely
finely, extremely sparsely punctate, sparsely pubescent. Median groove moderately deep, narrow, slightly constricted in
midregion, extremely faintly microreticulate. Anterior foveae circular, deep, moderately small, width equal distance
between fovea and median groove. Posterior foveae deep, length twice width, length twice that of anterior fovea, extremely
faintly microreticulate. Posterolateral angles with very shallow impressions. Prosternum with median carina ending at
coxal cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra: Length 0.96 mm; maximum width
(near midlength)0.72 mm. Disc convex, shiny, with six rows of round punctures between suture and humeri. Sides convex.
Elytra very slightly peaked at point where declivity begins, near posterior 0.33; intervals flat, width slightly greater than
puncture width; interstices between punctures 0.25 puncture length; each puncture with seta. Explanate margin
moderately developed. Abdomen: Basal four sterna with hydrofuge pubescence. Segments 5 and 6 shiny, sparsely
pubescent. Apical segment shiny. Legs: Moderately long and slender; ratio of hind leg length to abdominal length 1.8: 1.0.
Protarsomeres 1-3 without suction setae. Genitalia: Male (Figs. 93D,F)(6 examined).

Variation. - Other than slight aedeagal variation which I have illustrated (Figs. 93D,F), no
noteworthy variation was seen in the 61 specimens studied.

Distribution. - (Figs. 90A,179). Most specimens have been collected in northeastern United
States and adjacent areas of Canada. Two isolated localities, northern Montana and Ft.
Simpson Northwest Territories, indicates, however, that this species is trans-Canadian, and
might be Holarctic. If so, G. nitidus would be the only species of Gymnochthebius to be so
distributed. Further, its stem-species could have served as the ‘reservoir’ for allopatric
speciation of Gymnochthebius in the Palearctic Region. Two specimens have been found as far
south as Missouri. I have examined 61 specimens (see appendix).

Remarks. - Males have the labrum very slightly emarginate, with the emargination
distinctly upturned, but not in form of a dentiform process. Viewed from above, the anterior
margin appears evenly rounded, the upturned edge not apparent in outline. A tangential view of
the head displays the upturned edge nicely. Females have the labral emargination deeper and
lack the upturned edge. The holotype has the following labels: (blue disc turned gray-green)/
Type 313/ O. nitidus Lee.

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Figs. 90A - B, Geographical distributions of Gymnochthebius species. (A) G. nitidus. (B) G. topali 9 , G. retieulatus ★
and G. reticulatissimus A •

18. Gymnochthebius fossatus (LeConte)

(Figs. 89G,91 A-F,92B,179)

Ochthebius fossatus Leconte, 1855:362 (holotype male deposited in MCZ; type-locality: Colorado River, California,
U.S.A.). - LeConte, 1878:380. - Horn, 1890:22. - Fall, 1919:213. - Leech and Chandler, 1956:333.

Ochthebius tuberculatus LeConte, 1878:380 (holotype male deposited in MCZ; type-locality: New Mexico, U.S.A.). -
Horn, 1890:22. -Fall, 1919:213.

Ochthebius foveicollis LeConte, 1878:381 (lectotype male deposited in MCZ, here designated; type-locality: Enterprise,
Florida, U.S.A.). - Horn, 1890:20. - Fall, 1919:213.

Ochthebius parvulus Sharp, 1882:91 (lectotype female deposited in BMNH, here designated; type-locality: Guanajuato,
Mexico; new synonomy). - d’Orchymont, 1943:43.

Ochthebius nitiduloides d’Orchymont, 1943:43 (holotype male deposited in 1SNB; type-locality: Pernambuco, Brazil; new
synonomy).

Sharp’s type-specimen and d’Orchymont’s type-specimen do not differ significantly from
LeConte’s type-specimen. Refer to the diagnosis and remarks sections for additional
comments.

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Figs. 91A - G, Aedeagi of Gymnochthebius species. (A) G. fossatus, specimen from Brownsville, Texas. (B) G. fossatus,
Chapingo, Mexico, Mexico. (C) G. fossatus , Texcoco, Mexico, Mexico. (D) G. fossatus. Enterprise, Florida. (E) G.
fossatus, Goias, Brazil. (F) G. fossatus, Pernambuco, Brazil (drawn from holotype of G. nitiduloides d’Orchymont). (G)
G.falli, holotype.

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Diagnosis. - Adults of this species are easily confused with those of G. nitidus and G. falli.
Refer to the diagnoses of those species for comments regarding external characteristics. The
genitalia of G. nitidus males (Fig. 93D) are short, wide and with a general configuration that is
clearly discernible from those of G.fossatus and G. falli (Figs. 91A,G) males. The aedeagus of
G. falli males is somewhat broader than that of G. fossatus and the apex tapers more toward
the tip, resulting in a constricted appearance when compared with G. fossatus. As a result of
this tapering, width of the apical opening is less than width of a paramere at its apex in G. falli;
in G.fossatus the apical opening is twice the width of a paramere at its apex. Additionally, the
internal duct has its bend consistently near the apical 0.33 of the aedeagus in G. fossatus ,
whereas this bend is consistently near the apical 0.17 in G. falli. The consistency of 1) shape of
the apex; 2) arc of the internal duct; 3) general curve of the median lobe; and 4) external
characteristics; plus widespread geographical distribution are the primary reasons that G.
parvulus and G. nitiduloides are regarded as conspecific with G. fossatus, and their names are
here synonymized.

Description. — Form: Subovate, slightly convex (Fig. 89G). Size: Holotype male 1.26 mm long, 0.64 mm wide.
Color: Legs, palpi and elytral epipleura light brown, remainder dark brown. Head: Length 0.28 mm; width 0.39 mm.
Frons finely sparsely punctate, very sparsely pubescent; interocular foveae deep and large, width of each nearly 0.66
distance between them; interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture evenly arcuate.
Clypeus length 0.50 width, finely sparsely punctate, sparsely pubescent. Labroclypeal suture straight. Labrum length 0.33
width; finely sparsely punctate, sparsely pubescent; median emargination slightly developed, edge upturned; labrum evenly
rounded in habitus view. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 slightly greater than 0.50
length of 3. Mentum width equal length, shining, finely sparsely punctate; anterior margin arcuate. Submentum evenly,
finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at
midline 0.34 mm. maximum width (near anterior 0.33) 0.52 mm. Anterior hyaline border moderately wide in front of disc,
slightly wider in front of lateral fossulae. Lateral hyaline border origin near midlength of anterior lobe of lateral
depressions, moderately arcuate to posterior lobe, more markedly arcuate to posterior angles, very narrow around posterior
margin. Anterior margin of pronotum slightly arcuate in midregion. Lateral depressions nearly impunctate; anterior lobe
slightly longer than wide, slightly larger than posterior lobe, anterior extreme arcuate; posterior lobe angulate, angle nearly
right. Pronotum moderately constricted behind lateral depressions. Lateral fossulae deep, oval, length equal distance from
posterior margin of fossula to margin of pronotum. Pronotal disc shiny, very slightly convex, extremely finely, extremely
sparsely punctate, sparsely pubescent. Median groove moderately deep, moderately wide, slightly constricted in midregion,
extremely faintly microreticulate. Anterior foveae circular, deep, moderately small, width equal distance between fovea
and median groove. Posterior foveae deep, length twice width, length twice that of anterior fovea, extremely faintly
microreticulate. Posterolateral angles with very shallow impressions. Prosternum with median carina ended at coxal
cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra: Length 0.92 mm; maximum width (near
midlength) 0.64 mm. Disc flat, shiny, with six rows of round punctures between suture and humeri. Sides convex, declivity
origin near posterior 0.33; intervals flat, width slightly less than puncture width; interstices between punctures 0.25
puncture length; each puncture with seta. Explanate margin moderately developed. Abdomen: Basal four sterna with
hydrofuge pubescence. Segments 5 and 6 shiny, sparsely pubescent. Apical segment shiny; submedian setal group short.
Legs: Moderately long and slender; ratio of hind leg length to abdominal length 1.7: 1.0. Protarsomeres 1-3 without suction
setae. Genitalia: Refer to diagnosis for comments regarding the aedeagus (Figs. 91 A-F)(43 examined).

Variation. - Adults vary considerably in body size, ranging from approximately 1.20 -
1.52 mm for males, and 1.28 - 1.76 mm for females. This size variation is not correlated with
geographical distribution. Samples from proximate localities exhibit extremes of size variation.
For instance, some specimens from Mexico (Chiapas) are 1.21 mm (males) and 1.28 mm
(females), whereas some specimens from Mexico (Mexico) are 1.52 mm (males) and 1.76 mm
(females). Other representative body sizes are as follows (males/females): Arizona
(1.54/1.60); Florida (1.44/1.56); Venezuela (1.28/1.36); Brazil (1.32/1.40); Argentina
(1.45/1.56). Degree to which the anterior margin of the labrum is upturned in males varies
considerably, from the median region upturned to form a small tooth, to entire margin
upturned. Most populations exhibit the former condition; the latter condition reaches its
extreme in Brazilian populations. The elytra vary slightly. Some specimens of the Florida
population have the elytral apices more produced than usual. The segments of the Brazilian

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population studied have the elytral punctures slightly less developed than most other
populations.

Natural History. - Locality records indicate that G. fossatus is principally a stream form,
but has a rather wide ecological tolerance. My wife Maureen and I have collected adults at the
margins of tropical and desert streams in Central America. For example, we collected two
specimens from a small (two feet diameter), quiet water area at the edge of a stream at the
south end of Lago de Yojoa in Honduras, immediately after which a sudden rainstorm turned
the stream into a raging torrent, completely submerging the microhabitat in surging, swirling
water. In contrast, we found specimens in a small desert stream located on the central plateau
of Mexico, 29 mi. SW Zacatecas. Specimens have also been reported from drift in Pima
County, Arizona and from Lake Harney in Florida and Lake Texoma in Oklahoma. Of the 722
specimens studied, only two were taken at ultraviolet lights, and perhaps these were accidental
captures. Judging from the remarkably extensive geographical distribution of G. fossatus , one
might suspect that it is a facultative halophile, which apparently is not so.

Distribution. - (Figs. 92B,179). The range extends southward from the southern United
States through Central America and the Antilles to northern South America, Brazil and
Argentina. A total of 722 specimens have been examined (see appendix).

Remarks. - This species has been the object of much confusion in the literature since its
description by LeConte (1855) more than a century ago. This confusion was initiated by
LeConte when he described two additional species ( O . tuberculatus and O. foveicollis) 23 years
later for specimens which were actually conspecific with his O. fossatus. In the same
publication, Le Conte (1878) made the error of declaring as conspecific O. fossatus and O.
nitidus , a species he had described in 1850. Twelve years later, Horn (1850) added further to
the confusion by making O. tuberculatus the junior synonym of O. foveicollis , even though the
name O. tuberculatus had page priority. H. C. Fall (1919), however, detected all of these
previous errors, stating that O. nitidus was specifically distinct from O. fossatus , and that O.
tuberculatus , O. foveicollis and O. fossatus were conspecific. Considering the errors previous to
Fall’s publication, together with the fact that his decisions were made without the aid of male
genitalic characters, it is remarkable that he was able to state the situation correctly, and is an
example of the superior abilities of this fine taxonomist.

G. fossatus has the most extensive distribution of any Western Hemisphere hydraenid.
Variation is exhibited, as would be expected for a species so widely distibuted. I have dissected
many males from throughout the range to ensure that my concept of this species is correct.
Some of these genitalia are illustrated in this work to display the variation to be expected in G.
fossatus(Y\%s. 91A-F). Based upon the close similarity of these genitalic forms, I am confident
that these specimens represent a single, widely distributed species. Upon study of the
type-material of O. parvulus Sharp (1882) and O. nitiduloides d’Orchymont (1943), I have
found these to be conspecific with G. fossatus , and am here placing these names in synonomy.

The genitalia of the holotype of G. fossatus are in a microvial attached to the pin. The
following labels are also attached: (gold disc)/ Type 3065/ O. fossatus Lee. Col. The holotype
of O. tuberculatus LeConte is a female labelled as follows: N.M./ Type 3130/ O. tuberculatus
Lee./ (female sign). This specimen is clearly conspecific with O. fossatus and is also deposited
in the LeConte collection at the M.C.Z. The syntype-series of O. foveicollis LeConte at the
M.C.Z. consists of five specimens, all of which are conspecific with O. fossatus. All specimens
except number four are females. In the interest of stability, I have removed and studied the
male genitalia of this fourth specimen and am here designating it the lectotype of O. foveicollis

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LeConte and have affixed a label indicating such. The genitalia are in a microvial attached to
the pin. The following labels are also attached to the pin: Enterprise, Fla, May 26/ Type
4 3136/ foveicollis 4/ LECTOTYPE Ochthebius foveicollis LeConte by P.D. Perkins 1977.
Three female specimens comprise the syntype-series of O. parvulus Sharp in the British
Museum (Natural History). I have selected one of these as lectotype. The following labels are
attached to the pin: Ochthebius parvulus Type D.S., Guanajuato, Mexico,

Salle/ Syn-type/ B.C.A. Col. 1.2. Ochthebius parvulus , Sharp/ Sharp Coll. 1905. -
313./ LECTOTYPE Ochthebius parvulus Sharp by P.D. Perkins 1977.

19. Gymnochthebius falli new species
(Figs. 89F,91G,94B,179)

Type-locality. - McAllister, Logan County, Kansas, U.S.A.

Type-specimens. - The holotype male and allotype are deposited in the USNM. These
specimens, plus 35 paratypes (see appendix), were collected by Paul J. Spangler, August 29,
1956. Data about four additional paratypes are presented in the appendix.

Diagnosis. - Adults are very similar to those of G. nitidus and G. fossatus, especially the
latter. Refer to the diagnosis of G. nitidus for a comparison to that species. G. falli adults have
the following features which differ from those of G. fossatus: 1 ) generally larger size (males
ca.1.65 mm vs. 1.45 mm long); 2) elytra light brown, contrasting with dark brown pronotum
(both are dark brown in G. fossatus ); 3) Pronotum more elongate (compare Figs. 89F,G); 4)
elytra less ovate and slightly less convex; and 5) male genitalic form (compare Figs. 91G and
91A-F). The relatively restricted distribution of G. falli will also aid determinations where
specimens from Central and South America are involved. Refer to the diagnosis of G. fossatus
for further comment.

Description. — Form: Flattened, moderately elongate (Fig. 89F). Size: Holotype 1.64 mm long, 0.72 mm wide.
Color: Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.28 mm; width 0.41 mm. Frons finely
sparsely punctate, very sparsely pubescent; interocular foveae deep and large, width of each nearly 0.66 distance between
them; interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture evenly arcuate. Clypeus length 0.50
width, finely sparsely punctate, sparsely pubescent. Labroclypeal suture straight. Labrum length 0.33 width; finely
sparsely punctate, sparsely pubescent; median emargination weakly developed; entire anterior margin with upturned edge,
labrum apparently evenly rounded in habitus view. Maxillary palpus with palpomere 3 moderately wide; palpomere 4
slightly greater than 0.50 length of 3. Mentum width equal length, shining, finely densely punctate; anterior margin
arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate.
Thorax: Pronotum length at midline 0.40 mm; maximum width (near anterior 0.33) 0.56 mm. Anterior hyaline border
moderately wide in front of disc, wider in front of lateral fossulae. Lateral hyaline border origin near midlength anterior
lobe of lateral depressions, moderately arcuate to posterior lobe, more markedly arcuate to posterior angles, very narrow
around posterior margin. Anterior margin of pronotum slightly arcuate in midregion. Lateral depressions nearly
impunctate; anterior lobe longer than wide, asymmetrical, slightly larger than posterior lobe, anterior extremely arcuate;
posterior lobe angulate, angle nearly right. Pronotum moderately constricted behind lateral depressions. Lateral fossulae
deep, oval, length equal distance from posterior margin of fossula to margin of pronotum. Pronotal disc shiny, very slightly
convex, finely, sparsely punctate, sparsely pubescent. Median groove moderately deep, narrow, slightly constricted in
midregion, extremely faintly microreticulate. Anterior foveae circular, deep, moderately small, width equal distance
between fovea and median groove. Posterior foveae deep, narrow, length slightly greater than twice width, length twice
that of anterior fovea, extremely faintly microreticulate. Posterolateral angles with very shallow impressions. Prosternum
with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra:
Length 1.02 mm; maximum width (near midlength)0.72 mm. Disc flat, shiny, with 6 rows of round punctures between
suture and humeri. Sides convex, declivity origin near posterior 0.33; intervals flat, width equal puncture width; interstices
between punctures 0.25 puncture length; each puncture with seta. Explanate margin moderately developed. Abdomen:
Basal four sterna with hydrofuge pubescence. Segments 5 and 6 shiny, sparsely pubescent, both approximately equal in
length to apical segment. Apical segment shiny; submedian setal group short. Legs: Moderately long and slender; ratio of
hind leg length to abdominal length 1.8: 1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 9 1 G)( 1 1
examined).

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Figs. 92A - B, Geographical distributions. (A) Ochthebius kaszabi •, O. attritus ★ , Hydraena hyalina A and H.
browni ■.(B) Gymnochthebius fossatus.

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Variation. - Males vary in size from 1.64 x 0.72 mm to 1.72 x 0.76 mm; females vary from
1.72 x 0.76 mm to 1.96 x 0.84 mm. Specimens from Arizona have the anterior lobe of the
pronotal lateral depressions slightly longer and slightly more arcuate toward the anterior than
specimens from Kansas.

Etymology. - The specific epithet is a latinized form of the surname of that remarkable
amateur coleopterist, H.C. Fall.

Distribution. - (Figs. 94B,179). G. falli appears to be primarily a species of the
southwestern United States. Four rather widely separated localities are known: southern Idaho,
western Kansas, southern Arizona, and western Texas.

Remarks. - The sexes differ in shape of the labrum, which is upturned along the anterior
margin in males, whereas females have the edge on the same plane as the remainder of the
labrum.

The laevipennis Subgroup

Virtually impunctate elytra readily distinguish the rather attractive members of the
laevipennis subgroup. Most adults are very small, quite shiny and convex, with a wide lateral
hyaline border on the pronotum. Adults of some species are without one or both sets of pronotal
foveae.

The four species currently known in this subgroup live in southwestern and southcentral
United States, and in Central America.

20. Gymnochtlnebius laevipennis (LeConte)

(Figs. 89C,93E,G,H,94B,178)

Ochthebius laevipennis LeConte, 1878:381 (neotype female deposited in MCZ, herein designated; type-locality: Riverside,
California, U.S.A.). - Horn, 1890:20. - Hatch 1965:20. - Leech and Chandler, 1956:333.

Diagnosis. - Adults of this species and those of three others are the only New World

Gymnochthebius characterized by virtually impunctate elytra. Adults of all other known
species have rows of punctures. From G. perlabidus, one of the three other species with
impunctate elytra, G. laevipennis adults are differentiated by lack of posterior pronotal foveae.
Adults of G. laevipennis differ from those of G. maureenae in the shiny, less convex, more
elongate body and in pronotal form. These features and others that can be used to differentiate
these two species are discussed under G. maureenae . A comparison of G. laevipennis to its
closest relative, G. crassipes , is in the diagnosis section of the latter.

Description. — Form: Ovate, rather markedly convex (Fig. 89C). Size: Neotype 1.29 mm long, 0.64 mm wide.
Color: Dorsum and venter dark brown; legs, palpi and elytral epipleura brown. Head: Length 0.30 mm; width 0.38 mm.
Frons finely sparsely punctate, very sparsely pubescent; interocular foveae deep and large, width of each nearly 0.66
distance between them; interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture evenly arcuate.
Clypeus length 0.50 width, finely sparsely punctate, sparsely pubescent. Labroclypeal suture straight. Labrum length 0.33
width; finely sparsely punctate, sparsely pubescent; anterior margin shallowly emarginate. Maxillary palpus with
palpomere 3 moderately wide; palpomere 4 0.50 length of penultimate. Mentum width equal length, shining, finely densely
punctate; anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen.
Postgena finely punctulate. Thorax: Pronotum length at midline 0.36 mm; maximum width (near anterior 0.33) 0.58 mm.
Anterior hyaline border narrow in front of disc, much wider in front of lateral fossulae. Lateral hyaline border very broad,
origin near midlength of anterior lobe of lateral depressions, moderately arcuate to posterior lobe, more markedly arcuate
to posterior angles, very narrow around posterior margin. Anterior margin of pronotum very slightly arcuate in midregion.
Lateral depressions nearly impunctate; anterior lobe slightly longer than wide, slightly larger than posterior lobe, anterior
extreme arcuate; posterior lobe angulate, angle nearly right. Pronotum moderately constricted behind lateral depressions.

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Lateral fossulae deep, round, diameter equal to 0.33 distance from posterior margin of fossula to margin of pronotum.
Pronotal disc shiny, very slightly convex, extremely finely, extremely sparsely punctate, sparsely pubescent. Median
groove narrow, shallow. Anterior foveae circular, shallow, small, width equal to 0.50 distance between fovea and median
groove. Posterior foveae absent. Posterolateral angles lacking impressions. Prosternum with median carina ended at
coxal cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra: Length 0.82 mm; maximum
width (near midlength)0.64 mm. Disc convex, very shiny, nearly impunctate, with six rows of extremely short and fine
setae between suture and humeri. Sides convex. Elytra gradually sloping to rear, without marked point of declivity.
Explanate margin rather strongly developed. Abdomen: Basal four sterna with hydrofuge pubescence. Segments 5 and 6
shiny, sparsely pubescent. Apical segment shiny; submedian setal group short. Legs: Moderately long and slender; ratio
of hind leg length to abdominal length 1.7: 1.0. Protarsomeres 1-3 without suction setae. Genitalia: Refer to the
diagnosis of G. fossatus for comments on structure of the aedeagus (Figs. 93E,G)(4 examined); female (Fig. 93H)(1
examined).

Variation. - Males have the anteromedial margin of the labrum upturned in form of a
dentiform process; females do not have this process. No other notable variation was seen in the
24 specimens studied, (see appendix)

Distribution. - (Figs. 94B,178) G. laevipennis is distributed from southern Oregon south
through the coastal mountain ranges of California to Baja California.

Remarks. - Despite a thorough search of the LeConte Ochthebius types at the Museum of
Comparative Zoology, I was unable to find any specimens of O. laevipennis LeConte. The
H.C. Fall collection at that institution, however, had two female specimens of O. laevipennis,
one of which I designated as neotype. It is with the other LeConte Ochthebius types at the
MCZ labelled as follows: Riverside Cal., F.E. Winters/ H.C. Fall Collection/ NEOTYPE
Ochthebius laevipennis LeC. by P.D. Perkins 1977. According to the original description
(LeConte, 1878), the missing holotype was collected at Tejon, California. Although a major
portion of the range of this species has been rather extensively collected, only 24 specimens
were seen during this study. Whether this indicates an unusual, as yet unsampled biotope, or
small population size remains to be determined. I suspect the latter.

21. Gymnochthebius crassipes (Sharp)

(Figs. 93B,C,178)

Ochthebius crassipes Sharp, 1882:90. (lectotype male in BMNF1, here designated; type-locality: Duenas, Guatemala).

Diagnosis. - Shape of the pronotum is quite different from that of G. laevipennis , its closest
relative. In G. crassipes the anterior lobes of the lateral depressions are short and distinctively
deflexed, whereas those of G. laevipennis are longer (Figs. 89C,93B) and not deflexed. Stated
differently, the angle that forms the anterior and posterior lobes of each lateral depression is at
the anterior 0.33 in G. crassipes whereas it is at midlength in G. laevipennis . In addition, G.
crassipes lacks anterior foveae, this region being transversely, shallowly depressed. The anterior
foveae of G. laevipennis are well demarcated.

Other, less obvious differences include shape of the male labrum which is shallowly
emarginate and with the edge of the emargination upturned to from a dentiform process in G.
laevipennis . The labrum of G. crassipes (males) is more broadly emarginate and has the entire
anterior border upturned. The legs of G. crassipes are longer, and mesotarsomere 5 is angulate
at its base and quite thickened, hence Sharp’s specific epithet.

Description. — Form: Very convex, moderately ovate (Fig. 93B). Size: Lectotype is 1.56 mm long, 0.68 mm wide.
Color: Dorsum dark brown; venter brown. Head: Length 0.32 mm; width 0.42 mm. Frons extremely finely punctate;
interocular foveae deep and large, width of each 0.50 distance separating them; interocular tuberculi moderately large;
basomedial fovea transverse. Frontoclypeal suture angulate. Clypeus length 0.50 width; very finely sparsely punctate.
Labroclypeal suture straight. Labrum length 0.33 width; finely microreticulate; anterior border emarginate, edge
upturned. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of 3. Mentum width equal length,
finely punctate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena depressed,

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Figs. 93 A - J, Gymnochthebius. (A) G. oppositus , holotype aedeagus. (B) G. crassipes , body outline. (C) G. crassipes ,
lectotype aedeagus. (D) G. nitidus aedeagus, Illinois. (E) G. laevipennis aedeagus, Baja California, Mexico. (F) G. nitidus
aedeagus, Blaine County, Montana. (G) G. laevipennis aedeagus. Riverside County, California. (H) G. laevipennis,
spermatheca. (I) G. perlabidus, spermatheca. (J) G. maureenae, spermatheca.

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finely punctulate. Thorax: Pronotum length at midline 0.46 mm. maximum width (near anterior 0.33) 0.66 mm.
Anterior hyaline border narrow in front of disc, much wider in front of lateral fossulae. Lateral hyaline border very
broad, origin at apex of anterior lobe of lateral depressions, strongly arcuate to posterior angles, very narrow around
posterior margin. Anterior margin of pronotum weakly arcuate to front in midregion, markedly arcuate to rear laterally.
Lateral depressions very shiny, virtually impunctate; anterior lobes distinctively deflexed, width equal length, much
smaller than posterior lobes; posterior lobes in form of parallel sides, each posterior lobe angulate, angle nearly right.
Pronotum rather markedly constricted behind lateral depressions. Lateral fossulae circular, small, deep, diameter equal
to 0.20 distance from posterior margin of fossula to margin of pronotum, measured longitudinally. Pronotal disc very
convex and very shiny, extremely finely sparsely punctate. Median groove narrow, well defined. Anterior foveae absent,
this area with shallow transverse depression. Posterior foveae absent. Posterolateral angles without impressions. Elytra:
Length 0.94 mm. maximum width (near anterior 0.33) 0.68 mm. Disc very shiny and very convex, nearly impunctate.
Elytra gradually sloped to rear, without marked point of declivity. Explanate margin rather markedly developed in
anterior 0.50, absent from posterior 0.50. Abdomen: Basal four sterna with hydrofuge pubescence. Segments 5 and 6
shiny, sparsely pubescent. Apical segment shiny and with a small rounded elevation in midline; sparsely and randomly
pubescent at sides, without discrete rows of setae. Legs: Moderately long and somewhat stout; ratio of hind leg length to
abdominal length 2. 4: 1.0. Mesotarsomere 5 angulate near base and distinctly thickened. Protarsomeres 1-3 without
suction setae. Genitalia: Male (Fig. 93C)(1 examined).

Distribution. - (Fig. 178) Known only from the type-locality in Guatemala.

Remarks. - As Sharp (1882) stated in the original description, G. crassipes is truly a
“remarkable” species. The highly polished and very convex dorsal surface together with the
smooth contours of the pronotum and the very wide hyaline borders results in an elegant
appearance, like that of fine jewelry.

The thickened mesotarsus is quite certainly a modification to aid copulation, an aid
necessitated by the polished and convex dorsum. Sharp (1882) suggested that it was “probable,
from its strong middle legs, that it adheres to rocks in rapid water, as do the Henicoceri ”. The
convex shape of the body suggests, however, that this is not so. Indeed, even the postgena is
deeply indented to allow the head to be markedly deflexed, resulting in an even greater body
convexity. Perhaps members of this species prefer locations relatively high on stream banks
where interstitial space is adequate, as I (1976) have demonstrated for the convex O.

( Asiobates ) puncticollis.

22. Gymnochthebius perlabidus new species
(Figs. 89B, 931, 178)

Type-locality. - Hamburg Farm, Reventazon, Prov. Limon, Costa Rica.

Type-specimens. - The holotype female and one female paratype with same data are
deposited in USNM. These specimens were collected by F. Nevermann in 1933.

Diagnosis. - The two females are so distinctive that I have no reservations about describing
them even though males are not yet known. The three other Western Hemisphere
Gymnochthebius whose adults also possess virtually impunctate elytra, G. laevipennis , G.
crassipes , and G. maureenae, are without posterior pronotal foveae. These foveae are well
developed in G. perlabidus females. In addition, the spermatheca of these specimens is different
from the spermatheca of G. laevipennis females (Figs. 93H-I).

Description. — Form: Ovate, moderately convex (Fig. 89B). Size: Holotype 1.28 mm long, 0.64 mm wide. Color:
Brown. Head: Length 0.26 mm. width 0.38 mm. Frons extremely finely sparsely punctate, very sparsely pubescent;
interocular foveae deep and large, width of each nearly 0.66 distance between them; interocular tuberculi large;
basomedial fovea transverse. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width, finely sparsely punctate,
sparsely pubescent. Labroclypeal suture straight. Labrum length 0.33 width; finely sparsely punctate, sparsely pubescent,
weakly emarginate. Maxillary palpomere 3 moderately wide; palpomere 4 0.66 length of 3. Mentum width equal length, ,
shining, finely densely punctate; anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous.
Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.34 mm; maximum width (near
anterior 0.33) 0.56 mm. Anterior hyaline border narrow in front of disc, wider in front of lateral fossulae. Lateral hyaline

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border origin near apex of anterior lobe of lateral depressions, arcuate to posterior angles, very narrow around posterior
margin. Anterior margin of pronotum slightly arcuate in midregion. Lateral depressions nearly impunctate; anterior
lobe width equal length, much larger than posterior lobe, anterior extreme arcuate; posterior lobe angulate, angle nearly
right. Pronotum markedly constricted behind lateral depressions. Lateral fossulae large, very deep, oval, length equal
distance from posterior margin of fossula to margin of pronotum. Pronotal disc shiny, convex, extremely finely,
extremely sparsely punctate, sparsely pubescent. Median groove narrow, shallow, extremely faintly microreticulate.
Anterior foveae circular, deep, moderately small, width equal to 0.50 distance between fovea and median groove.
Posterior foveae moderately deep, length twice width, length twice that of anterior foveae. Posterolateral angles without
impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median
glabrous area. Elytra: Length 0.84 mm; maximum width (near midlength)0.64 mm. Disc convex, impunctate, extremely
finely, extremely sparsely pubescent. Sides convex. Elytra gradually sloped to rear, without marked point of declivity.
Explanate margin rather markedly developed. Abdomen: Basal four sterna with hydrofuge pubescent. Segments 5 and 6
shiny, sparsely pubescence. Apical segment setose. Legs: Moderately long and slender; ratio of hind leg length to
abdominal length 1.8: 1.0. Protarsomeres 1-3 without suction setae. Genitalia: Female (Fig. 93 1 )(2 examined); male
unknown.

Variation. - No notable variation was seen in the two available specimens.

Distribution. - (Fig. 178) Known only from the type-locality in Costa Rica.

Etymology. - From the Latin per (very) and labidus (slippery). I refer to the very smooth
dorsal surface and aquatic habits of this species.

Remarks. - The specimens were collected from a “puddle”.

23. Gymnochthebius maureenae new species
(Figs. 89A,93J,178)

Type-locality. - Lucedale, George County, Mississippi, U.S.A.

Type-specimens. - The holotype female is deposited in USNM. Female paratypes are
deposited in USNM (1) and PDP (2). All specimens were collected by H. Dietrich in 1930.

Diagnosis. - The differences between adults of this species and those of the three other
species which also lack rows of elytral punctures are so distinctive that I have no reservations
concerning its validity even though males are not yet available. G. maureenae adults are similar
to those of G. laevipennis in that both lack posterior pronotal foveae, in contrast to adults G.
perlabidus which have these depressions. However, G. maureenae adults differ from G.
laevipennis adults in a number of respects, the most obvious being dull dorsal surface and more
robust body form. G. laevipennis adults are extremely shiny, less convex and more elongate.
Additionally, the following features differ in the two species: 1) form of anterior pronotal
margin (evenly arcuate in G. maureenae', G. laevipennis with pronounced excavations in front
of lateral fossulae) (Figs. 89A,C); 2) pubescence of lateral areas of pronotum (dense in G.
maureenae, very sparse in G. laevipennis ); 3) size of lateral fossulae (much larger than
anterior foveae in G. maureenae, equal in size, or slightly smaller than anterior foveae in G.
laevipennis ); 4) elytral sculpture near apex (very shallow grooves in G. maureenae , smooth in
G. laevipennis ).

Description. — Form: Broadly ovate, very convex (Fig. 89A). Size: Holotype 1.20 mm long, 0.64 mm wide. Color:
Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.26 mm; width 0.40 mm. Frons dull, finely sparsely
punctate, finely microreticulate, very sparsely pubescent; interocular foveae deep and large, width of each 0.50 distance
between them; interocular tuberculi large; basomedial fovea transverse. Frontoclypeal suture evenly arcuate. Clypeus dull,
length 0.50 width, finely microreticulate, sparsely pubescent. Labroclypeal suture straight. Labrum length nearly 0.33
width; finely microreticulate, feebly emarginate. Maxillary palpus very short, palpomere 3 wide; palpomere 4 0.33 length
of 3. Mentum width equal length, finely microreticulate. Submentum evenly, finely punctulate, punctures contiguous.
Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.36 mm; maximum width (near
anterior 0.33) 0.62 mm. Anterior hyaline border narrow in front of disc, slightly wider in front of lateral fossulae. Lateral
hyaline border very wide, origin at apex of anterior lobe of lateral depressions, markedly arcuate to base, very narrow
around posterior margin. Anterior margin of pronotum slightly arcuate, without emarginations in front of lateral

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Perkins

Figs. 94A - B, Geographical distributions of Gymnochthebius species. (A) G. oppositus. (B) G.falli • and G. laevipennis

★ .

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depressions. Lateral depressions dull, nearly impunctate, very finely microreticulate; anterior lobe longer than wide
much larger than posterior lobe, anterior extreme arcuate; posterior lobe angulate, angle nearly right, posterior side of
lobe very hairy. Pronotum markedly constricted behind lateral depressions. Lateral fossulae large, deep, oval; anterior
margin ended abruptly, posterior area gradually elevated to level of surrounding surface. Pronotal disc dull, finely
microreticulate. Median groove narrow, shallow. Anterior foveae circular, deep, moderately large, width equal distance
between fovea and median groove. Posterior foveae absent. Posterolateral angles without impressions. Prosternum with
low median carina ended at coxal cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra:
Length 0.80 mm; maximum width (near midlength) 0.64 mm. Disc very convex, dull, finely microreticulate, without
discrete rows of punctures; with rows of very short setae. Declivity origin near midlength. Explanate margin well
developed. Abdomen: Basal four sterna with hydrofuge pubescence. Segments 5 and 6 shiny, sparsely pubescent. Apical
segment shiny; setae randomly placed, not in discrete rows. Legs: Moderately short and very stout; ratio of hind leg
length to abdominal length 2.0:1. 0. Protarsomeres 1-3 without suction setae. Genitalia: Female (Fig. 93J)(1 examined);
male unknown.

Variation. - Too few specimens are available to adequately assess variation.

Distribution. - (Fig. 178) Known only from the type-locality in George County, Mississippi,
U.S.A.

Etymology. - I am pleased to dedicate this species to my wife Maureen, who has been a
constant source of encouragement and aid during the course of this study.

The oppositus Subgroup

This distinctive subgroup contains species whose adults are very small, and have the
posterior lobes of the lateral depressions larger than the anterior lobes, a condition opposite that
seen in the remainder of the genus. The elytra are costate or subcostate and the dorsal
pubescence is well developed, especially on the pronotum.

The two species presently known, one each from Mexico and Florida, are apparently
adapted to brackish water habitats.

24. Gymnochthebius oppositus new species
(Figs. 9I,89E,93A,94A)

Type-locality. - Two miles north of La Paz, Baja California, Mexico.

Type-specimens. - The holotype male is deposited in CAS. This specimen and one male
paratype (PDP) with identical locality data were collected by Hugh B. Leech, December 29,
1958. The allotype is deposited in USNM, and has the following data: Mexico, Veracruz, 8 mi.
NE Panuco, 28-VIII- 1 965, P.J. Spangler. One additional paratype male is deposited in MCZ:
Texas, Cameron County, Brownsville, 16-VI-1933, Darlington.

Diagnosis. - Within Gymnochthebius , only G. oppositus and G. seminole adults have the
posterior lobe of the pronotal lateral depressions larger than the anterior lobe. From G.
seminole , G. oppositus adults are distinguished by the adpressed versus decumbent setae on
the elytral intervals, among other features. Refer to the diagnosis of G. seminole for further
comparisons.

Description. — Form: Truncate, somewhat flattened (Fig. 89E). Size: Holotype 1.32 mm long, 0.62 mm wide.
Color: Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.26 mm; width 0.36 mm. Frons finely
sparsely punctate, sparsely pubescent; interocular foveae deep and large, width of each nearly 0.66 distance between them;
interocular tuberculi small; basomedial fovea transverse. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width,
finely sparsely punctate, prominently pubescent. Labroclypeal suture straight. Labrum length 0.33 width; finely sparsely
punctate, sparsely pubescent; median emargination slightly developed, with upturned edge in form of very small tooth in
habitus view. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 slightly greater than 0.50 length of 3.
Mentum width equal length, shining, moderately densely punctate; anterior margin arcuate. Submentum evenly, finely

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punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at
midline 0.34 mm; maximum width (near anterior 0.33) 0.50 mm. Anterior hyaline border moderately wide in front of
disc, slightly wider in front of anterior foveae, then tapered to anterior angles. Lateral hyaline border origin near
midlength of anterior lobe of lateral depressions, moderately arcuate to posterior lobe, more markedly arcuate to
posterior angles, very narrow around posterior margin. Anterior margin of pronotum slightly arcuate in midregion.
Lateral depressions prominently pubescent along margins, nearly impunctate; anterior lobe angulate, anterior extreme
acute, slightly smaller than posterior lobe. Posterior lobe rectangular, posterior angle in form of small tooth. Pronotum
markedly constricted behind lateral depressions. Lateral fossulae deep, with prominent setae at posterior extreme.
Pronotal disc shiny, convex, impunctate, with long, moderately sparse hairs at margins of foveae. Median groove deep,
moderately wide, slightly constricted in midregion, extremely faintly microreticulate. Anterior foveae large, deep, width
twice distance between fovea and median groove. Posterior foveae deep, arcuate, length three times width, length twice
that of anterior fovea. Posterolateral angles lacking impressions. Prosternum with median carina ended at coxal cavities;
coxae contiguous. Metasternum median glabrous area large, with vertical lateral margins. Elytra: Length 0.80 mm;
maximum width (near midlength) 0.62 mm. Disc flat, shiny, with six rows of round punctures between suture and
humeri, punctures apparently without setae. Sides convex, declivity origin near posterior 0.33. Intervals slightly
elevated, width equal puncture width, each interval with a row of adpressed setae. Interstices between punctures
0.25-0.50 puncture length. Explanate margin moderately developed, with a narrow fringe of short setae in anterior 0.25.
Abdomen: Basal four sterna with hydrofuge pubescence. Segments 5 and 6 shiny, sparsely pubescent. Apical segment
shiny; submedian setal group short. Legs: Moderately long and slender; ratio of hind leg length to abdominal length
1.7: 1.0. Posterior tibiae widest near midlength. Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 93A)(3
examined); female (Fig. 9 1 )( 1 examined).

Variation. - The Brownsville, Texas specimen has the apex of the posterior lobes of the
lateral depressions slightly bifid, whereas those of the Baja California specimens are not.

Natural History. - This unusual species is presently represented by only four individuals
from three widely separated localities. Two specimens are from La Paz, Baja California
(approximately 24 degrees north latitude). Another specimen is from Brownsville, Texas
(approximately 26 degrees north latitude). The fourth specimen is from Panuco, Veracruz,
Mexico (22 degrees north latitude). Remarkably, no specimens have been collected in the area
between the eastern and western sites, which includes the greatest width of Mexico. This
disjunct distribution is probably a result of lack of adequate sampling in appropriate habitats.

The specimens collected by Hugh B. Leech in La Paz bear the label notation: “in brackish
(tidal) pool”. The only known specimen of the closely related G. seminole , collected by
W.R. Suter, was taken from the Everglades, Florida in a “sawgrass-mangrove area”. Further
collecting in these habitats, which are unusual (but not unique) for Western Hemisphere
hydraenids, will undoubtedly reveal additional specimens, and perhaps additional species.

Distribution. - (Fig. 94A) Known from three disjunct localities: La Paz, Baja California,
Mexico; Veracruz, Mexico; and Brownsville, Texas.

Etymology. - Latin oppositus (on the other side, contrary). This is in reference to the shape
of the pronotum which, with the posterior lobes larger than the anterior lobes, is opposite the
condition seen in all known Gymnochthebius species but one, G. seminole. The “O’s” in the
name are suggestive of the oval shape of these beetles.

25. Gymnochthebius seminole new species
(Figs. 89D,95C)

Type-locality. - Five miles North of Flamingo, Everglades National Park, Monroe County,
Florida, U.S.A.

Type-specimen. - The holotype male (unique) is deposited in USNM. The specimen was
collected by W. Suter in 1965.

Diagnosis. - This distinctive species, presently known from a single male specimen collected
in the Florida Everglades, is readily recognized by virtue of a set of unusual characteristics. The

Figs. 95A - D, Aedeagi of holotypes. (A) Gymnochthebius bartyrae. (B) G. bisagittatus. (C) G. seminole. (D) Hydraena
paeminosa.

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short (1.20 mm), robust body form and costate elytra together with the fact that the lateral
depressions of the pronotum have the posterior lobe larger than the anterior lobe make this
species different from all other Gymnochthebius species except one, oppositus. From G.
oppositus , G. seminole is distinguished by its geographical distribution and condition of elytral
setae. These setae are decumbent on the elytral intervals and for the entire length along the
elytral margin in G. seminole . However, in G. oppositus the setae are adpressed on the
intervals and less apparent on the margin. The amount of pubescence extending laterally from
the sclerotized part of the pronotum reaches its greatest expression, among New World
Gymnochthebius , in these two species.

Description. — Form: Truncate, robust (Fig. 89D). Size: Holotype 1.20 mm long, 0.64 mm wide. Color: Dorsum
and venter black; legs and palpi dark brown. Head: Length 0.26 mm; width 0.36 mm. Frons finely sparsely punctate,
prominently pubescent; interocular foveae deep and large, width of each equal distance separating them; interocular
tuberculi small; basomedial fovea transverse. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width, finely
sparsely punctate, prominently pubescent. Labroclypeal suture straight. Labrum length 0.33 width; finely sparsely
punctate, sparsely pubescent; median emargination absent. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4 slightly greater than 0.50 length of 3. Mentum width equal length, shining, densely, deeply punctate.
Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax:
Pronotum length at midline 0.32 mm; maximum width (near anterior 0.33) 0.56 mm. Anterior hyaline border moderately
wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border
origin near midlength of anterior lobe of lateral depressions, moderately arcuate to posterior lobe, more markedly arcuate
to posterior angles, very narrow around posterior margin. Anterior margin of pronotum slightly arcuate in midregion.
Lateral depressions very prominently pubescent at sides, nearly impunctate; anterior lobe angulate, anterior extreme acute,
slightly smaller than posterior lobe; posterior lobe rectangular, posterior angle forming a small tooth. Pronotum markedly
constricted behind lateral depressions. Lateral fossulae deep, prominently pubescent at posterior extreme, otherwise
non-pubescent. Pronotal disc prominently pubescent, shiny, convex, extremely finely, extremely sparsely punctate. Median
groove deep, moderately wide, slightly constricted in midregion, extremely faintly microreticulate. Anterior foveae
cirrcular, very deep, moderately large, width slightly greater than distance between fovea and median groove. Posterior
foveae deep, length three times width, length twice that of anterior fovea. Posterolateral angles without impressions.
Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternal median glabrous area large, with
vertical lateral margins. Elytra: Length 0.78 mm; maximum width (near midlength) 0.64 mm. Disc very convex,
moderately shiny, with six rows of round punctures between suture and humeri, punctures apparently lacking setae. Sides
convex, declivity origin near posterior 0.33. Intervals slightly elevated, width 0.50 puncture width, each interval with a row
of short, decumbent setae. Interstices between punctures 0.25 puncture length. Explanate margin moderately developed,
with dense fringe of short, decumbent setae, from anterior angles to apices. Abdomen: Basal four sterna with hydrofuge
pubescence. Segments 5 and 6 shiny, sparsely pubescent. Apical segment shiny; submedian setal group short. Legs:
Moderately short and stout; ratio of hind leg length to abdominal length 1.6: 1.0. Posterior tibiae widest near midlength.
Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 95C)(1 examined); female unknown.

Natural History. - The specimen was collected in “Snake Bight trail, sawgrass-mangrove
area”, August 27, 1965. For a discussion of the habitats of G. seminole and G. oppositus , refer
to the “Natural History” section of the latter.

Distribution. - Known only from the type-locality in Florida.

Etymology. - seminole is a noun in apposition referring to the Seminole Indians of the
Florida Everglades.

GENUS OCHTHEBIUS LEACH

Ochthebius Leach, 1815:95 (type-species: Elophorus marinus Paykull, 1798:245). - LeConte, 1878:378. - Kuwert,
1887:369. - Horn, 1890:17. - Knisch, 1924. - d’Orchymont, 1932, 1933, 1940, 1941a, 1941b, 1942a, 1942b, 1942c,
1943a, 1943b. - Leech and Chandler, 1956. - F.Balfour-Browne, 1958.

Discussion. - The genus Ochthebius is a diverse and widespread group, species being found
on all continents and many islands. It is not yet reported from New Zealand (Wise, 1973) and
the subantarctic islands, where, however, the related genus Meropathus is found (Ordish,
1971).

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293

In the Western Hemisphere the majority of Ochthebius species are in western United States
and Mexico, but the genus is represented in all areas of North America except northernmost
Canada and a large portion of southeastern United States (Fig. 161).

Other than two species of Ochthebius in northernmost South America, O. lineatus and O.
attritus (Figs. 92A,107), plus an undescribed species in the biincisus Group from Colombia (I
have seen only a single female), the genus is replaced in South America by Gymnochthebius
(Fig. 161).

Gymnochthebius was formerly treated as a subgenus of Ochthebius (d’Orchymont, 1943b),
but is herein accorded equal rank based upon morphologic and zoogeographic considerations
(refer to the section on Gymnochthebius for a discussion of these topics).

A detailed analysis of Ochthebius and Gymnochthebius distribution is presented in the
section on zoogeography.

The European components of the genus have received much more attention than those in the
Western Hemisphere, principally by Armand d’Orchymont in the 1930’s and 1940’s. Much of
d’Orchymont’s work included clarifying the numerous subgenera erected by Kuwert (1887).
Although d’Orchymont (1941a, 1941b, 1942a, 1942b) recognized some previously described
subgenera and described additional subgenera (1933, 1943), other workers have more-or-less
ignored the subgeneric categories.

Horn (1890), in his review of the 13 species of Ochthebius then known from North America,
refers thusly to Kuwert’s subgenera: “In a study of our species in a comparison with those of
Europe it is possible, by allowing a little latitude to the subgenera, to admit certain of our
species, while a number might warrant the formation of other subdivisions, but it seems to me
unnecessary to burden our nomenclature with names for generic groups which have not full
generic value.”

Likewise, F.Balfour-Browne (1958) in his review of the British species, expressed his dislike
for subgenera within Ochthebius : “Unfortunately, these groups have been described as
subgenera although in at least some of them there is no justification for regarding them as
natural groups.”

More recently, Janssens (1969) has described a new species (O. elegans ) which forms the
transitional stage between Kuwert’s Dory ochthebius and Wollaston’s Calobius subgenera, and
has therefore placed Dory ochthebius into synonomy. It is apparent that as more and more
species are discovered and described, the distinctions between at least some of the subgenera of
Ochthebius become less and less.

It is not my intent to present a complete worldwide review of the subgroups of Ochthebius
and their relative rankings. Rather, I wish to point out that the Western Hemisphere
components of Ochthebius (not including Meropathus, Gymnochthebius and Neochthebius)
appear to form two major groups, one being Ochthebius (sensu stricto) Leach and the other O.
( Asiobates ) Stephens.

Ochthebius cribricollis LeConte of Canada and the United States (Fig. 136D) has
consistently been placed in O. (Homalochthebius) Kuwert (Horn, 1890; Knish, 1924;
d’Orchymont, 1942a; Hatch, 1965). This subgenus is characterized by combination of deeply
excavate posterior angles of the pronotum and absence of pronotal foveae. The only difference,
therefore, between Homalochthebius and Asiobates is lack of pronotal foveae in adults of the
former taxon.

Body shape of O. similis adults (Fig. 136B) is very suggestive of O. cribricollis (Fig. 136D)
adults, but the former have well developed posterior pronotal foveae. Indeed, aedeagi of males

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Figs. 96A - F, Pronota of Ochthebiinae. (A) Ochthebius rectus. (B) Gymnochthebius nitidus. (C) O. angularidus. (D) O.
benefossus. (E) O. discretus. (F) O. aztecus (arrows indicate postocular emargination and process).

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295

of the two species (Figs. 138B-D) indicate a close relationship. Another transitional stage is
seen in O. brevipennis, whose adults are closely similar externally to those of O. cribricollis,
(Fig. 136F). However, the former are without a transverse depression at the posterior extreme
of the median groove which could be considered the first stage in loss (or formation) of foveae.

These two species might not form the phylogenetic nexus between Homalochthebius and
Asiobates per se, but the characters upon which Homalochthebius is based are probably of a
transitory and reversible nature.

In fact, if one compares illustrations of aedeagi of males of the species placed in
Homalochthebius by d’Orchymont (1942a), without exception the parameres diverge from the
main-piece. Likewise, parameres of Asiobates (Figs. 141 A-D,144A-E) males constantly
diverge from the main-piece in the same manner (see illustrations in d’Orchymont, 1940, 1941b
for Palearctic Asiobates ).

By contrast, however, the parameres of male Ochthebius (sensu stricto)
(Figs. 100A-D,1 14A-E) are invariably along the main-piece. Judging from the illustrations
provided by d’Orchymont, this type of aedeagus is found in Ochthebius ( sensu stricto) (1943),
O. (Hymenodes) Mulsant (1942b, 1942c), and O. (Henicocerus) (1941a).

It appears that the two aedeagal groups mentioned above are constant and the monophyly of
each inferred from aedeagal structure is supported by external characteristics, as similarity of
illustrations of body outline provided herein reveals.

Ochthebius benefossus LeConte was placed in O. ( Henicocerus ) by Knisch (1924). This
species is obviously not closely related to any other Western Hemisphere Ochthebuis , as its
body outline, pronotum, and aedeagal apex testify (Figs. 96D,131A,132B). Further, it is the
only species of Ochthebius in the Appalachian Mountains. However, it is obviously more closely
related to Ochthebius (sensu stricto ) than to O. (Asiobates), including the relationship between
the parameres and the main-piece. Consequently, I have included O. benefossus in Ochthebius
(sensu stricto ).

Most early descriptions of North American Ochthebius were made by J.L. LeConte,
beginning with O. cribricollis and O. nitidus in 1850 and continuing to 1878. In all, LeConte
described 13 species of North American Ochthebius.

Horn (1890) provided the only comprehensive treatment of the genus, his study including
the 13 species then recognized as valid for North America, but omitting those described by
Sharp (1882, 1887) from Mexico and Guatemala.

Between 1890 and 1978, taxonomic work on Ochthebius consisted of isolated species
descriptions, including those by Fall (1910, 1919), Blatchley (1910), Darlington (1928), Brown
(1931,1933) and d’Orchymont (1943b). Hatch (1965) provided a key to those species living in
the Pacific Northwest, and described three new species. Wood and Perkins (1978) described
two new species (O. leechi and O. spanglerorum) from western North America.

Study of types has revealed the following new synonomies (junior synonyms in parentheses):
similis Sharp 1882 (wickhami Fall 1901); aztecus Sharp 1887 ( bruesi Darlington 1928);
discretus LeConte 1878 ( insulanus Brown 1931); attritus LeConte 1878 ( schubarti
d’Orchymont 1943); lineatus LeConte 1852 ( milleri Hatch 1965); interruptus LeConte 1852
(aberti Hatch 1965).

In all, 53 species of Ochthebius are now recognized from the Western Hemisphere: 23 were
previously described; 30 are new.

Quaest. Ent., 1980, 16 (1,2)

296

Perkins

Figs. 97A - F, Ochthebius body outlines. (A) O. arenicolus. (B) O. pacificus. (C) O.
interrupt us. (F) O. borealis.

lecontei. (D) O. sierrensis. (E) O.

Western Hemisphere Hydraenidae

297

Figs. 98A - F, Ochthebius structures. (A) O. interruptus, pronotum (AHB == anterior hyaline border, LD = lateral
depression, AF = anterior fovea, LHB = lateral hyaline border, LF = lateral fossula, PF = posterior fovea, MG =
median groove). (B) O. interruptus, palpi and labrum. (C) O. interruptus 6 protarsus, (D) O. lineatus 6, labral
emargination. (E) O. lineatus, cupule and associated antennal segments. (F) O. lineatus, maxilla.

Quaest. Ent., 1980, 16 (1,2)

298

Perkins

Pronotal features. - The major features of Ochthebius pronota (Fig. 98A) include anterior
hyaline border (AHB), lateral depressions (LD), anterior foveae (AF), lateral hyaline border
(LHB), lateral fossulae (LF), posterior foveae (PF) and median groove (MG). In adults of
certain species the foveae and/or median groove are absent or modified. For example, in O.
lineatus adults (Fig. 103 A) the foveae are joined to form longitudinal depressions; in adults of
O. marinus (Fig. 106 A) the foveae are joined to form a transverse depression and the median
groove is obsolete; in those of O. similis (Fig. 136B) the anterior foveae are absent; and in those
of O. cribricollis (Fig. 136D) both anterior and posterior foveae are absent. In adults of O.
mexicanus (Fig. 128 A) and related species the pronotum has emarginations behind the eyes,
which are termed postocular emarginations.

Diagnosis. - Nine antennomeres , palpal form and lateral hyaline border on the pronotum
distinguish adults of Ochthebius from those of other genera except Gymnochthebius. Most
species of Gymnochthebius can be discerned by their characteristic pronotal shape, but a few
species of the two genera must be distinguished by aedeagal form or amount of hydrofuge
pubescence on abdominal sternum 5 (see diagnosis section of Gymnochthebius).

Description. — Form: Generally elongate-oval, moderately convex, rarely truncate and convex. Size: Length
1.30-2.50 mm, width 0.50-1.14 mm. Most females slightly larger than males. Color: Most adults dark brown, some with
metallic copper or purple reflections, some black, others testaceous. Head: Moderately finely punctate to crenulate,
generally with well developed microreticulation dorsally. Interocular foveae moderately to well developed. Interocular
tuberculi (ocelli) present. Clypeus margin upturned, less so or not in females. Maxillary palpus relatively short,
palpomere 3 thickened. Mentum width and length equal. Genae swollen, shiny. Antennomeres nine (4 + 5). Thorax:
Pronotal form markedly varied, adults of some species with sides weakly sinuate, others deeply incised; hyaline border thin
to very wide; anterior depressions generally well developed. Disc of most specimens with anterior and posterior foveae, few
specimens with these longitudinally united as sulci, or anterior foveae obsolete; median groove well developed to obsolete.
Posterior margin of pronotum slightly arcuate to rear. Prosternum with low median carina ended at coxae; latter
contiguous. Metasternum glabrous or pubescent in midregion. Elytra: Disc with six rows of punctures between suture and
humeri, adults of some species striate-punctate, each puncture with seta. Intervals flat, rounded or costate. Explanate
margin slightly to markedly developed. Abdomen: Commonly with basal five sterna hydrofuge pubescent, apical two
without hydrofuge pubescence; few with sternum 6 hydrofuge pubescent also. Legs: Length moderate, slender in some
species, stout in others. Males with large pads of suction setae in some species, absent from others. Genitalia: Aedeagus
with preterminal, mobile piece. Spermatheca as illustrated (Figs. 10A-F).

Key to Subgenera of Western Hemisphere Ochthebius

1 Pronotum with sclerotized part sinuate on sides, very shallowly

(Figs. 96A,F,97A-F, 98 A) or very deeply (Figs. 96D,1 16A-F); many specimens
with acute, produced point at juncture of convex (anterior) and concave
(posterior) portions of sinuation (Figs. 125A-F); if concave (posterior) portion
very deep (Figs. 116A-C), sides rounded, not angulate as in Asiobates.
Aedeagus with parameres next to main-piece for their entire length, or nearly
so; parameres not divergent from main-piece at their bases (Figs. 114A-E).

Range-North, Central and South America and the Galapagos Islands

Ochthebius ( sensu stricto ), p. 305

V Pronotum with sclerotized portion transverse, sides gradually rounded from
anterior angles to middle or slightly beyond, then excavate

(Figs. 96C,E,133A-F,136A-F). Aedeagus with parameres divergent from
main-piece at their bases (Figs. 138A-E,141 A-D,144A-E). Range-North and
Central America Asiobates Stephens, ps 376

Western Hemisphere Hydraenidae

299

Key to Western Hemisphere species of Ochthebius (sensu stricto)

1 ( 0 ) Lateral hyaline border of pronotum within sinuation behind lateral depression

(Figs. 96D,132B); Appalachian Mountains of eastern United States ( benefossus

Group) O. benefossus LeConte, p

1' Lateral hyaline border extended laterally as far as or beyond lateral depression
(Figs. 96A-F,98A); northern South America, Central America, Antilles, and
North America except Appalachian Mountains

2 ( 1') Anterior margin of pronotum with more or less developed postocular

emarginations and postocular processes (Figs. 96F,1 19B,E-H,125A-F,128A);
metasternum entirely pubescent, without median glabrous area ( biincisus

Group except attritus and batesoni)

2' Anterior margin without distinct postocular emarginations; postocular processes
absent or extremely small (Figs. 96A,98A,103A,106A,1 15A); metasternum
entirely pubescent or with glabrous area

3 (2') Anterior margin of pronotum bisinuate (Figs. 115A,116A-F )(bisinuatus

Group)

y Anterior margin of pronotum straight or arcuate (Figs. 96A,98A,103A,106A)
(interruptus Group, plus attritus and batesoni)

4 ( 3 ) Elytral intervals costate; California (Figs. 1 16C,1 18B)

O. costipennis Fall, p.

4 ' Elytral intervals flat or rounded, not costate

5 ( 4') Pronotal disc crenulate; northern California, Oregon, Idaho

(Figs. 1 16B,1 14C,D) O. crenatus Hatch, p.

5' Pronotal disc not crenulate

6 ( 50 Lateral hyaline borders of pronotum broad, with anterior extremes at or very

near anterior angles; pronotum rugulose, anterior margin crenulate in front of

lateral depressions; California, western Nevada (Figs. 1 16D,1 18D)

O. californicus, new species, p.

6' Lateral hyaline border less broad, with anterior extremes near anterior 0.33 of
lateral depressions; pronotum not rugulose, anterior margin not crenulate . . .

7 ( 6') Pronotal disc markedly elevated, foveae and median groove very deeply

impressed; lateral depressions ended abruptly, with posterior margins thickened;
elytral disc subconvex, sloped abruptly from near posterior 0.33 to apices;

California (Figs. 1 16A,1 18 A) O. crassalus , new species, p.

7' Pronotal disc not markedly elevated, foveae and median groove moderately
impressed; lateral depressions tapered at posterior extremes, posterior margins
not thickened; elytral disc relatively flat, sloped very gradually from near
posterior 0.33 to apices; western North America

8 ( 7') Black, ca. 1.80 mm long; pronotum with anterior margin less distinctly

bisinuate; northern California and southern Oregon (Figs. 1 16E,1 14E)

O. richmondi, new species, p.

8' Brown to dark brown, ca. 1.68 mm long; pronotum with anterior margin more
distinctly bisinuate; widely distributed in western North America
(Figs. 1 16F,1 14B) O. bisinuatus, new species, p.

9 ( 3') Pronotum with lateral depressions nearly parallel anteriorly, markedly arcuate

posteriorly (Figs. 96A,112D-F); metasternum totally pubescent ( rectus

374

2

23

3

4

9

341

5

343

6

338

7

343

8

339

336

Quaest. Ent., 1980, 16 (1,2)

300

Perkins

Subgroup) 10

9' Pronotum with lateral depressions gradually arcuate (Figs. 98A,106A);

metasternum totally pubescent or with median glabrous area 12

10 ( 9 ) Small, ca. 1.60 mm long; Colusa County, California (Figs. 1 12D,1 13C)

O. recticulus, new species, p. 332

10' Larger species, ca. 1.80-2.20 mm long 11

11 (10') Brown, broader, more coarsely punctate, punctural interstices of pronotum

generally smaller than punctures; pronotal foveae less apparent, obscured by
punctation; pronotum more distinctly setose; coastal areas of western United

States and Baja California (Figs. 1 12F,1 14A)

O. rectusalsus, new species, p. 331

11' Black, narrower, less coarsely punctate, punctural interstices of pronotum

generally larger than punctures; pronotal foveae more apparent; pronotum less

distinctly setose; western North America (Figs. 1 12E,1 13A,B)

O. rectus LeConte, p. 329

12 (9') Pronotum with posterior foveae broadly confluent, not separated by well-defined

median groove; if posterior foveae narrowly confluent with median groove, then
anterior and posterior foveae of a side united in form of sinuate line (certain

specimens of O. lineatus) (Figs. 103A,106A,C,E) {borealis Subgroup) 13

12' Pronotum with posterior foveae distinct on each side of median groove; if
narrowly confluent with median groove then anterior and posterior foveae of a
side distinct, not united in form of sinuate line (Figs. 97A-E,98A) ( interruptus
Subgroup) 17

13 (12) Pronotum and elytra dark brown (northern morph) or testaceous (southern

morph); lateral margins of anterior and posterior pronotal foveae of a side
united in form of sinuate line or not so; male with anteromedial edge of labrum
upturned in form of dentiform process; western and southern Canada south to

Colombia (Figs. 98D-F,108C,D,1 19 A) O. lineatus LeConte, p. 314

1 3' Pronotum and elytra brown to black; anterior and posterior foveae of a side not
united; males with anteromedial margin of labrum arcuate or slightly
emarginate, not upturned in form of dentiform process; northern and western
North America 14

14 (13') Posterior pronotal foveae oval, with lateral and medial extremes similar in

appearance, both gradually sloped; microreticulation of pronotal foveae and
lateral depressions uniform; coastal areas of Washington, Oregon and California

(Figs. 105B, 110D) O. uniformis, new species, p. 321

14' Posterior pronotal foveae generally not oval, magins ended abruptly, lateral
margins of foveae in form of straight line or not; microreticulation of pronotal
foveae and lateral depressions uniform or not 15

15 (14') Black; interfoveal area of pronotum at least partially to totally microreticulate;

metasternal median area glabrous; elytral intervals flat

(Figs. 97F,106E,F,1 10A-C) O. borealis , new species, p. 322

15' Brown; interfoveal area with or without microreticulation; metasternal median

area glabrous or pubescent; elytral intervals flat or rounded 16

16 (150 Elytral intervals rounded, somewhat elevated; metasternal median area varied

from glabrous in posterior 0.20 to totally pubescent (Figs. 105C,106C,D,108A)

Western Hemisphere Hydraenidae

301

O. kaszabi Janssens, p.

16' Elytral intervals flat; metasternal median area glabrous in posterior 0.50
(Figs. 105A,106A,B,108B) O. marinus (Paykull), p.

17 (12') Metasternum with large median glabrous area

17' Metasternum entirely pubescent

18 (17 ) Median groove lightly impressed, or absent in middle of pronotum; postocular

processes absent; pronotal punctation lightly impressed; males with
anteromedial margin of labrum upturned, but not in form of prominent
dentiform process; southern British Columbia south to northeastern Nevada

(Figs. 97C,100C) O. lecontei, new species, p.

18' Median groove more markedly impressed, not absent from middle of pronotum;

postocular processes more or less developed; pronotal punctation generally more
markedly impressed; males with anteromedial margin of labrum upturned in
form of prominent dentiform process

19 (180 Body slightly more parallel sided; color generally darker; postocular processes

generally less prominent; pronotal sculpture generally less markedly impressed;

Galapagos Islands (Figs. 1 19D,143D)

O. batesoni Blair, p.

19' Body slightly less parallel sided; color generally lighter, many specimens with
testaceous pronotum and elytra; postocular processes generally more prominent;
pronotal sculpture generally more markedly impressed; areas bordering Gulf of
Mexico and Caribbean Sea, including Florida, Texas, Yucatan, Colombia,

Cuba, Dominican Republic and Puerto Rico (Figs. 102A-D,1 19C)

O. attritus LeConte, p.

20 (17') Pronotum with origin of lateral hyaline borders at or very slightly posterior to

anterior angles (Figs. 97E,98A,100D)

O. interruptus LeConte, p.

20" Origin of lateral hyaline borders posterior to anterior angles of pronotum, near
midlength of lateral depressions (Figs. 97A,B,D)

21 (20') Brown; extremely slight indication of postocular emarginations of pronotum;

California, western slope of Sierra Nevada mountains (Figs. 97D,1 18C)

O. sierrensis, new species, p.

21' Black; no indication of postocular emarginations; California, coastal mountain
ranges (Figs. 97 A, B)

22 (21') Body shorter, wider, elytral length less than twice pronotal width

(Figs. 97B,100A) O. pacificus, new species, p.

22' Body longer, narrower, elytral length greater than twice pronotal width
(Figs. 97A,100B) O. arenicolus, new species, p.

23 ( 2 ) Abdominal sternum 6 with hydrofuge pubescence (Figs. 96F,1 19B,120A-D) . .

O. aztecus Sharp, p.

23' Abdominal sternum 6 without hydrofuge pubescence

24 (23') Pronotum with median groove strongly constricted in midregion, anterior and

posterior portions oval; anterior foveae distinctly separated from median groove

by shiny relief (Figs. 1 12A,C,125D)

24' Pronotum with median groove absent, markedly reduced, or markedly confluent
with anterior and posterior foveae, anterior and/or posterior portions of median

325

318

18

20

308

19

349

346

311

21

313

22

306

307

359

24

25

Quaest. Ent., 1980, 16 (1,2)

302

Perkins

groove indistinguishable from confluent foveae 27

25 (24 ) Black; postocular emarginations deep; processes behind lateral depressions well

developed; lateral hyaline borders convergent to base; coastal areas of California

and Oregon (Figs. 125D,126A)

O. biincisus, new species, p. 361

25' Brown; postocular emarginations shallow; processes behind lateral depressions

very small or absent; lateral hyaline borders nearly parallel sided; Rocky
Mountain region of United States (Figs. 1 12A,C) 26

26 (25') Male genitalia and body outline as illustrated (Figs. 1 12C,124A)

O. spanglerorum Wood and Perkins, p. 359

26' Male genitalia and body outline as illustrated (Figs. 1 12A,124B)

O. alpinopetrus, new species, p.357

27 (240 Pronotum with area between posterior foveae flat, surface smooth and shiny

between punctures (Figs. 125 A, 126B) O. obscurus Sharp, p. 372

27 ' Pronotum with posterior foveae more or less confluent, microreticulate 28

28 (270 Pronotum with areas between fossulae and posterior foveae dull,

microreticulate 29

28' Areas between fossulae and posterior foveae shiny, non-microreticulate or very

faintly so 32

29 (28 ) Pronotum with lateral depressions distinctly convex, somewhat inflated 30

29 ' Lateral depressions flat, not inflated 31

30 (29 ) Pronotum with postocular emarginations deeper; coastal ranges of southern

Oregon, California and Baja California (Figs. 1 19F,120E)

O. sculptus LeConte, p. 352

30' Postocular emarginations shallower; western North America

(Figs. 1 19G,H,122A-F) O. sculptoides new species, p. 351

31 (29') Smaller, ca. 1.60 mm long; postocular emarginations deeper; male labral
emargination deeper; color copperish in many specimens; median groove
generally not connected to deeply confluent posterior foveae; northern Mexico to

Guatemala (Figs. 1 19E,129A-C) O. mesoamericanus, new species, p. 373

31' Larger, ca. 1.77 mm long; postocular emarginations shallower; male labral
emargination shallower; color dark brown or black; median groove generally
connected to confluent posterior foveae; western United States, northern Mexico
(Figs. 1 12B,124C,D) O. tubus, new species, p. 355

32 (28') Pronotum with shallow postocular emarginations (Figs. 125E,F) 33

32' Pronotum with deep postocular emarginations (Figs. 125B,C) 34

33 (32 ) Elytra striate-punctate; Oaxaca, Mexico (Figs. 125F,129D)

O. pauli, new species, p.368

33' Elytral rows of punctures not striate; southeastern Arizona, northern Mexico

(Figs. 1 25E, 131 B) O. madrensis, new species, p. 366

34 (32") Pronotum with postocular emarginations very deep; lateral depressions with
posterior process large; foveae and median groove deep; elytra shallowly

striate-punctate; Mexico (Figs. 125C,128A-F,129E)

O. mexcavatus, new species, p. 368

34' Pronotum with postocular emarginations moderately deep; lateral depressions
with posterior processes small; foveae and median groove very shallow; elytra

Western Hemisphere Hydraenidae

303

not striate-punctate; southern California, northern Baja California, Arizona
35 (34') Aedeagus with apical piece markedly arcuate, thin border wide; apex of
main-piece wider, less acute; coastal mountains of southern California, northern

Baja California (Figs. 125B,126C)

O. gruwelli, new species, p.

35' Aedeagus with apical piece not markedly arcuate, thin border very narrow; apex

of main-piece thinner, more acute; eastern Arizona (Fig. 126D)

O. arizonicus, new species, p.

Key to Western Hemisphere species of Ochthebius (Asiobates)

1 (0) Large (ca. 2.10-2.80 mm long), coarsely punctate (Figs. 133A,C,136A,C);

aedeagus without process on terminal piece (Figs. 144A-E) {puncticollis

Group)

r Medium to small (ca. 1.60-2.20 mm long); aedeagus with process on terminal
piece (Figs. 141 A,B,D) ( discretus Group)

2 (1) Pronotum without postocular emarginations (Fig. 13 3C)

O. leechi Wood and Perkins, p.

2 ' Pronotum with postocular emarginations

3 ( 2') Pronotum with sides of lateral depressions angulate in middle; southern Texas,

northern Mexico (Figs. 96C,1 36A)

O. angularidus, new species, p.

3' Pronotum with sides of lateral depressions gradually arcuate, not angulate in
middle; California, Baja California, Arizona and Utah

4 ( 30 Elytra broadly explanate, flange as wide as tibia; pronotal lateral hyaline

borders markedly convergent to base (Fig. 136C)

O. martini Fall, p.

4 ' Elytra not broadly explanate, flange not as wide as a tibia; pronotal hyaline

borders not markedly convergent to base (Fig. 133A)

O. puncticollis LeConte, p.

5 (10 Pronotum with well developed anterior foveae {discretus Subgroup)

5' Pronotum without anterior foveae, this region flat and moderately punctate or
somewhat depressed and densely, coarsely punctate

6 ( 5 ) Blackish, more linear and less convex; lateral depressions generally more

concave at rear and more markedly punctate; common; western North America

(Figs. 96E,133D,134A,B) O. discretus LeConte, p.

6' Brownish, more ovate and more convex species; lateral depressions less concave
at rear and less markedly punctate; rare

7 ( 6") Pronotum with lateral depressions slightly deflexed in anterior 0.50, typically

subangulate laterally; postocular emarginations and processes well developed;
posterior angles of sclerotized part of pronotum in form of produced point;
United States, Pacific Northwest and British Columbia, Canada

(Figs. 133E,138A) O. mimicus Brown, p.

7' Pronotum with lateral depressions in same plane throughout, without deflexion
in anterior 0.50, typically arcuate laterally; postocular emarginations and
processes small or absent; posterior angles of pronotum not distinctly acute;

35

365

366

2

5

403

3

402

4

400

399

6

10

377

7

383

Quaest. Ent., 1980, 16 (1,2)

304

Perkins

8 (7')

8'

9 (80

9'

10 (50

10'

11 (10)
ir

12 (no

12'

13 (12)
13'

14 (12')
14'

15 10'
15'

16 (15')

California to northern Canada 8

Pronotum finely, sparsely punctate; lateral depressions shorter, ended near
midlength of pronotum; lateral hyaline border wider along lateral depressions;

Oregon and northern Northwest Territories (Figs. 132C,134C)

O. hibernus, new species, p. 381

Pronotum deeply, moderately coarsely and densely punctate; lateral depressions
larger, ended past midlength of pronotum; lateral hyaline border narrower along

lateral depressions 9

Large (ca. 1.96-2.00 mm long); puncture density on pronotal disc rather
uniform throughout; median groove shallower; Marin County, California and

Multnomah County, Oregon (Figs. 1 33B, 1 4 1 B)

O. orbus, new species, p. 382

Small, more convex (1.44 mm long); punctures on pronotal disc dense along
median groove, sparse laterally; median groove deeper; Putnam County, Indiana
(Fig. 133F) O. putnamensis Blatchley, p. 385

Pronotum densely, coarsely punctate in region generally occupied by anterior
foveae, in many specimens this region transversely depressed; posterior foveae

present ( reticulocostus Subgroup) 11

Pronotum flat and sparsely punctate in region usually occupied by anterior

foveae; posterior foveae present or absent 15

Pronotum without postocular emarginations; Arizona, New Mexico, Texas,
probably northern Mexico (Figs. 136E,141D)

O. apache , new species, p. 391

Pronotum with well developed postocular emarginations 12

Dorsum markedly, completely microreticulate; elytral intervals costate 13

Pronotal disc without microreticulation on punctural interstices; elytral intervals
costate or not, but not markedly microreticulate 14

Smaller, narrower, ca. 1.64 x 0.76 mm (Fig. 140A); microreticulation more

markedly developed; Nayarit and Mexico, Mexico

O. reticulocostus , new species, p. 394

Larger, broader, ca. 2.28 x 1.04 mm (Fig. 140C); microreticulation less
markedly developed; Mexico, Mexico

O. mexicanus, new species, p. 394

Body short, stout, spindle shaped (Fig. 136E); elytral intervals subcostate;
mountains of southern Mexico and Guatemala

O. apicalis Sharp, p. 397

Body not especially stout or spindle shaped (Fig. MOB); elytral intervals less
elevated; Mexico, Mexico

O. browni, new species, p. 393

Pronotum with posterior foveae; Arizona, Mexico (Figs. 136B,138B) ( similis

Subgroup) O. similis Sharp, p. 385

Pronotum without posterior foveae; Pacific Coast states of U.S.A.,

transcontinental near Canada-U.S. A. border (cribricollis Subgroup) 16

Pronotum with shallow transverse depression at posterior end of median groove;
elytra shorter in relation to pronotal length; southern British Columbia,
Washington, Oregon and northern California (Figs. 136F,138E)

Western Hemisphere Hydraenidae

305

O. brevipennis , new species, p. 389

16' Pronotum without shallow transverse depression at posterior end of median
groove; elytra longer in relation to pronotal length; Quebec west to British

Columbia, then south to southern California (Figs. 136D,138C,D)

O. cribricollis LeConte, p. 388

Ochthebius ( sensu stricto) Leach

As is described in the key to the subgenera, adults of Ochthebius (sensu stricto ) are
distinguished from those of O. (Asiobates) by pronotal and aedeagal differences.

Figs. 99A - C, Geographical distributions of Ochthebius species. (A) O. lecontei • and O. sierrensis ★ . (B) O.
spanglerorum • and O. alpinopetrus ★ . (C) O. benefossus.

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The interruptus Group

Members of this group are characterized by shape of the anterior pronotal margin, which
varies from straight to moderately arcuate. Dorsal form and sculpture vary considerably within
the group, which includes three subgroups.

Thirteen species currently comprise the group, which has a very extensive range, and
includes two holarctic species ( O.marinus and O. kaszabi ). The Western Hemisphere
components are widespread in North, Central and northern South America. One species ( O .
batesoni) is in the Galapagos Islands. Species are notably absent from the Appalachian
Mountains of the eastern United States.

The interruptus Subgroup

Adults of species in this subgroup are characterized by pronotal shape and sculpture. The
lateral depressions are not markedly arcuate posteriorly, hence the sides of the pronotum are
gradually sinuate (Fig. 98A). Posterior foveae are usually distinct on each side of the median
groove, but in some adults are narrowly confluent with the median groove. In the latter
specimens, the anterior and posterior foveae of a side are distinctly separated from one another,
not united to form a sinuate line.

Geographical distribution of this lineage (Fig. 183) is restricted to western North America.

1. Ochthebius pacificus new species
(Figs. 97B,100A,101A,183)

Type-locality. - Sonoma, Sonoma County, California, U.S.A.

Type-specimens. - The holotype male and allotype are deposited in CAS. Both specimens
were collected by H.B. Leech in 1950, and have identical locality data. Data about paratypes
(230) are presented in the appendix.

Diagnosis. - O. pacificus adults are externally very similar to those of O. arenicolus in that
both groups are small and black with the anterior margin of the pronotum straight and
generally with pronotal foveae well separated from the median groove. Ordinarily, O.
arenicolus adults have the posterior foveae more distinctly separated from the median groove
than have O. pacificus adults. However, overlap in this characteristic makes it unreliable for
purposes of determination. Likewise, although the median emargination of the labrum is
generally deeper in O. pacificus adults, there is some overlap which negates this structure as a
distinguishing characteristic. The most consistent external character of diagnostic value is body
form (Figs. 97A,B). O. pacificus adults are more robust, with the elytral length less than twice
the pronotal width; O. arenicolus adults are less robust, with the elytral length more than twice
the pronotal width. Unequivocal identification should be based upon the aedeagal shapes,
which are quite dissimilar (Figs. 100A,B).

Description. — Form: Ovate, weakly convex (Fig. 97B). Size: Holotype 1.60 mm long, 0.80 mm wide. Color: Head
and pronotum black; elytra dark brown; venter dark brown; legs and palpi brown. Head: Length 0.28 mm; width 0.42 mm.
Frons with lightly impressed punctures rather small, separated by twice puncture diameter; microreticulation more evident
in lateral areas; surface moderately shining in midline, without obvious hairs; interocular foveae deep and large, width of
each nearly 0.66 distance between them; interocular tuberculi moderately large and distinct; basomedial fovea nearly as

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deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with fine,
contiguous microreticulation and fine hairs. Labroclypeal suture straight. Labrum length nearly 0.50 width; surface
with fine, irregularly spaced punctures and rather dense hairs; median emargination shallow and narrow, depth nearly
0.25 length of labrum, width 0.13 width of labrum, edge upturned, semi-transparent; in habitus view emargination
appears smaller than it is. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 slightly greater than 0.50
length of 3. Mentum nearly square, anterior margin arcuate, shining, with moderately dense, deep punctures.
Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate.
Thorax: Pronotum length at midline 0.38 mm; maximum width (at approximately midlength)0.59 mm. Anterior hyaline
border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border origin near anterior 0.50 of lateral depression, slightly arcuate to posterior angles, very narrow
around posterior margin. Anterior margin of pronotum straight, without crenulations in front of lateral fossulae; with
extremely shallow excavation in front of each lateral depression; anterior angles obtuse. Lateral depressions slightly
convex, with microreticulation and small indistinct hairs; margins moderately arcuate, pronotum moderately constricted
behind lateral depressions. Lateral fossulae with inner margin abrupt, posterior extreme tapered into lateral hyaline
border . Pronotal disc moderately convex, microreticulation markedly impressed in and at margins of median groove and
foveae, area between groove and foveae with microreticulation extremely finely impressed, surface therefore rather
shiny; punctation in shiny area sparse and moderately large; hairs sparse and fine. Median groove moderately deep and
wide, tapered at ends, extended nearly to anterior and posterior margins; with punctation more markedly impressed
than that of disc. Anterior foveae rather shallow, suboval, connected to median groove by very shallow depression, latter
with markedly impressed microreticulation; lateral and medial margins indistinct. Posterior foveae oval, elongate and
oblique, length slightly greater than twice width, width twice that of median groove; surface sculpture as in median
groove; all margins not ended abruptly. Posterolateral angles with distinct impressions. Prosternum with median carina
ended at coxal cavities; coxae contiguous. Metasternum without median glabrous area. Elytra: Length 1.00 mm;
maximum width (near midlength) 0.72 mm. Disc somewhat flattened, moderately dull, with six rows of punctures
between suture and humeri. Elytra sloped gradually to posterior, without marked declivity; most punctures slightly
elongate; intervals flat, width equal to puncture diameter; interstices between punctures 0.25 puncture diameter; each
puncture with very small, indistinct seta. Explanate margin moderately developed. Abdomen: Basal five sterna with
hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs:
Medium build and length; ratio of hind leg length to abdominal length 1.5/ 1.0. Protarsomeres 1-3 with suction setae.
Genitalia: Male (Fig. 100A)(45 examined).

Variation. - This species is relatively constant throughout its rather limited range. Some
specimens have the posterior pronotal foveae joined by a very shallow depression, but the
median groove is quite apparent between the posterior foveae. Degree of development of the
median emargination of the labrum (in both sexes) is also subject to slight variation. Other
variation seen in certain specimens includes; 1) elytra black instead of dark brown; 2) lateral
margins of posterior foveae ended abruptly instead of gradually; 3) excavations in front of
lateral depressions clearly evident instead of nearly imperceptible; and 4) microreticulation of
pronotal disc between foveae and median groove absent instead of very lightly impressed.
Females lack the protarsal suction setae of males, and have the labral margin on the same plane
as remainder instead of being upturned.

Distribution. - (Figs. 101A,183). Ranges along the Pacific coastal region from Washington
south to southern California. One locality from southern Nevada known.

Etymology. - Latin, pacificus (peaceful). I refer to the geographical distribution.

2. Ochthebius arenicolus new species
(Figs. 97A,100B,101B,183)

Type-locality. - Tributary of E. branch Little Indian Creek, 6.2 mi. S. Lodoga, Colusa Co.,
California, U.S.A.

Type-specimens. - Holotype male and allotype deposited in CAS. Hugh B. Leech collected
these specimens, which have the same locality data, in 1966. Data about paratypes (320) are
presented in the appendix.

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Diagnosis. - Adults of this species are easily confused with those of O. pacificus. Refer to
the latter species for a comparison of external characters.

Description. — Form: Ovate, moderately convex (Fig. 97A). Size: Holotype 1.66 mm long, 0.72 mm wide. Color:
Dorsum and venter black; legs and palpi brown. Head: length 0.28 mm; width 0.44 mm. Frons with microreticulation in
lateral areas; punctures in midline only, separated by twice puncture diameter or greater; surface shining, without obvious
hairs; interocular foveae deep and large, width of each nearly 0.66 distance between them; interocular tuberculi large,
distinct; basomedial fovea nearly as deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus
length 0.50 width, microreticulate; punctures very lightly impressed, with fine, obvious hairs. Labroclypeal suture straight.
Labrum length 0.50 width; surface with fine punctures and fine, moderately dense hairs; median emargination shallow and
narrow, depth 0.20 length of labrum, width 0.20 width of labrum, edge upturned; in habitus view emargination apparently
smaller. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of penultimate. Mentum square,
anterior margin arcuate; moderately shining, with dense, deep, small punctures. Submentum evenly, finely punctulate,
punctures contigous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.38 mm;
maximum width (near anterior 0.33) 0.58 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in
front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin near anterior 0.33 of lateral
depression, extended slightly arcuate to posterior angles, very narrow around posterior margin. Anterior margin of
pronotum straight, without crenulations in front of lateral fossulae and without shallow excavations in front of each lateral
depression; anterior angles obtuse. Lateral depressions slightly convex, with punctation and small indistinct hairs; margins
moderately arcuate, pronotum moderately constricted behind lateral depressions. Lateral fossulae with inner margin
abrupt, posterior extremely tapered into lateral hyaline border. Pronotal disc moderately convex, microreticulate,
punctation well developed in median groove and foveae; area between foveae and median groove with punctures only,
punctures separated by twice puncture diameter, surface shiny. Median groove moderately deep and wide, tapered at ends,
extended nearly to anterior and posterior margins; punctate and microreticulate. Anterior foveae rather shallow, suboval,
connected to median groove by very shallow microreticulate depression, lateral margin straight and nearly parallel to
median groove; median margin arcuate. Posterior foveae oval, elongate and oblique, length slightly greater than twice
width, width twice that of median groove; surface sculpture as in median groove; lateral margin ended slightly more
abruptly than median. Posterolateral angles with distinct impressions. Prosternum with median carina ended at coxal
cavities; coxae contiguous. Metasternum without glabrous area. Elytra: Length 1.12 mm; maximum width (near
midlength) 0.76 mm. Disc somewhat flattened, moderately dull, with six rows of punctures between suture and humeri.
Elytra sloped gradually to posterior, without marked declivity; most punctures slightly elongate; intervals flat, width 0.50
puncture diameter; interstices between punctures 0.25 puncture diameter; each puncture with small seta. Explanate
margin rather narrow. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50
glabrous, apical 0.50 with very short hairs. Legs: Of medium build and length; ratio of hind leg length to abdominal length
1. 8:1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 100B)(76 examined).

Variation. - Other than minor variations in depth of pronotal foveae, populations are
relatively uniform throughout the range of this species. Further discussion of variation is
presented in the diagnosis of O. pacificus. Females lack the upturned edge of the labral
emargination and protarsal suction setae.

Distribution. - (Figs. 101 B, 183) Coastal mountain ranges of southern Oregon, California
and Baja California.

Etymology. - Latin, arena (sandy place) plus icolus (dweller). Individuals live at margins of
sandy streams.

3. Ochthebius lecontei new species
(Figs. 97C,99A, 1 00C, 183)

Type-locality. - Ski-jump pond, Vernon, British Columbia, Canada.

Type-specimens. - The holotype male and allotype are deposited in CAS. Both specimens
were collected in Vernon by Hugh B. Leech; the holotype in 1942, the allotype from “pond 3”
in 1941. Data about paratypes (44) are presented in the appendix.

Diagnosis. - Dorsally adults look rather like very small adults of O. interruptus. Ventrally
they are quite dissimilar, as the metasternum is totally hydrofuge pubescent in O. interruptus ,
but has a large glabrous area in O. lecontei. The more lightly impressed pronotal sculpture of O.
lecontei , plus widely separated distributions, and aedeagal form discriminate between O.

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Figs. 100A D, Aedeagi of Ochthebius species. (A) O. pacificus, holotype. (B) O. arenicolus, holotype. (C) O. lecontei ,
holotype. (D) O. interruptus , specimen from Mendocino County, California (inset: Lake County, Oregon, drawn from
paratype of O. aberti Hatch).

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Figs. 101 A - F, Geographical distributions of Ochthebius species. (A) O. pacificus. (B) O. arenicolus. (C) O. interrupt us.
(D) O. rectus. (E) O. rectusalsus, • and O. recticulus ★ . (F) O. bisinuatus.

1/ !~

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lecontei and the two closely similar species with glabrous metasterna: O. attritus and O.
batesoni.

Description. — Form: Ovate, weakly convex (Fig. 97C). Size: Holotype 1.56 mm long, 0.72 mm wide. Color:
Dorsum and venter dark brown; legs and palpi light brown. Head: Length 0.26 mm; width 0.42 mm. Frons with very small,
sparse punctures, surface shiny, without obvious hairs; interocular foveae deep and large, width of each nearly 0.66
distance between them; interocular tuberculi moderately large; basomedial fovea nearly as deep as interocular foveae,
smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; microreticulation in posterior 0.50, anterior 0.50
shiny, with very fine, sparse punctures; with fine, very sparse hairs. Labroclypeal suture straight. Labrum length nearly
0.50 width; surface with fine punctures and moderately dense hairs; median emargination very shallow with edge strongly
upturned; in habitus view upturned edge obscured by emargination, anterior margin apparently entire. Maxillary palpus
with palpomere 3 moderately wide; palpomere 4 0.50 length of 3. Mentum width equal length, moderately shining, with
sparse, small punctures; anterior margin arcuate. Submentum evenly, finely punctulate. Genae shining, swollen. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.36 mm; maximum width (near anterior 0.33) 0.54 mm. Anterior
hyaline border moderately wide in front of disc, considerably wider in front of lateral fossulae, then tapered to anterior
angles. Lateral hyaline border origin near anterior 0.33 of lateral depression, extended slightly arcuate to posterior angles,
very narrow around posterior margin. Anterior margin of pronotum arcuate, without crenulations in front of each lateral
depression; anterior angles obtuse. Lateral depressions flat, with microreticulation, small punctures, and small hairs;
margins moderately arcuate; pronotum moderately constricted behind lateral depressions. Lateral fossulae moderately
deeply impressed, with well developed microreticulation; inner margin abrupt, posterior extreme tapered into lateral
hyaline border. Pronotal disc moderately convex, punctures extremely fine and very sparse; with fine, sparse hairs; surface
between punctures smooth and shiny. Median groove apparent in anterior and posterior as very shallow, smooth
depression, middle of disc slightly elevated and without groove. Anterior foveae shallow, elongate ovals separated from
median groove by four times fovea width; connected to median groove by very shallow, smooth depression with denser
punctation than that of remainder of pronotum. Posterior foveae elongate grooves separated from median area by four
times fovea width; shallow depression connecting fovea to median groove. Posterolateral angles with distinct impressions.
Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median glabrous area.
Elytra: Length 1.00 mm; maximum width (near midlength) 0.72 mm. Disc slightly rounded, moderately dull, with six
rows of punctures between suture and humeri. Sides convex, declivity beginning near posterior 0.33; most punctures
somewhat elongate; intervals flat, width equal puncture width; interstices between punctures 0.50 puncture length; each
puncture with seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence.
Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and
slender; ratio of hind leg length to abdominal length 1.7: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male
(Fig. 100C)( 18 examined).

Variation. - Specimens from British Columbia are ordinarily darker and have the pronotal
sculpture less impressed. In southern populations the pronotal groove is complete in some
specimens, not obsolete in the midregion as it is in the holotype.

Distribution. - (Figs. 99A,183). An unusual distribution, with specimens from the Great
Basin (southwestern Utah; northeastern Nevada), the Columbia Plateau (western Washington)
and southern British Columbia. One locality is known in the Rocky Mountains of southwestern
Montana.

Etymology. - Dedicated to J. L. LeConte, in recognition of his contributions to the
taxonomic literature of North American Ochthebius.

4. Ochthebius interruptus LeConte
(Figs. 97E,98A-C,100D,101C,183)

Ochthebius interruptus LeConte, 1852:210 (holotype female in MCZ; type-locality: San Diego, California, U.S.A.). -
LeConte, 1855:361 .- LeConte, 1878:379. - Horn, 1890:23. - Darlington, 1928:3. - Leech and Chandler, 1956:333.-
Hatch, 1965:17.

Ochthebius aberti Hatch, 1965:18 (holotype female in UWA; type-locality: Abert Lake, Lake County, Oregon, U.S.A.;
new synonomy).

LeConte’s holotype is damaged, the head plus prothorax being severed from the pterothorax,
as is the left elytron. These body parts are glued to the point with the remainder of the
specimen. I have illustrated (Fig. 100D) the apex of the adeagus of a paratype of O. aberti
Hatch.

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Diagnosis. - Form of the pronotum (Fig. 98A) with its arcuate anterior margin, broad
hyaline borders which attain the anterior angles and the weakly convex disc with its distinct
foveae and median groove serve to distinguish adults of this species from others of the genus.

Description. — Form: Ovate, moderately convex (Fig. 97E). Size: Holotype 1.62 mm long, 0.73 mm wide. Color:
Dorsum and venter dark brown; legs and palpi light brown. Head: Length 0.30 mm; width 0.40 mm. Frons with
moderately large, dense punctures in midline, surface shiny, with very fine hairs; interocular foveae deep and large, width
of each nearly 0.66 distance between them; interocular tuberculi moderately large; basomedial fovea nearly as deep as
interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with microreticulation,
moderately dense punctures, and fine hairs. Labroclypeal suture straight. Labrum length 0.33 width; surface with small
punctures and fine, dense hairs; median emargination of moderate depth. Maxillary palpus with palpomere 3 moderately
wide; palpomere 4 0.50 length of 3. Mentum width equal length, markedly shining, with sparse, small punctures; anterior
margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely
punctulate. Thorax: Pronotum length at midline 0.38 mm; maximum width (near anterior 0.33) 0.56 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border origin slightly posterior to anterior angles, extended arcuate to posterior angles, very narrow around
posterior margin. Anterior margin of pronotum arcuate, without crenulations in front of lateral fossulae and without
shallow excavation in front of each lateral depression; anterior angles acute. Lateral depressions flat, with punctures,
microreticulation, and fine hairs; margins moderately arcuate. Pronotum moderately constricted behind lateral
depressions. Lateral fossulae moderately deeply impressed, with well developed microreticulation; inner margin abrupt,
posterior extreme tapered into lateral hyaline border. Pronotal disc moderately convex, punctures moderately large,
separated by one-two times puncture diameter; with fine, sparse hairs; surface between punctures smooth and shiny.
Median groove microreticulate, moderately deep, moderately wide, tapered at anterior and posterior, not extended to
anterior and posterior margins; Anterior foveae oval, moderately large, separated from median groove by width of fovea;
connected to median groove by shallow depression. Posterior foveae oval, oblique, with abrupt lateral margins;
posteromedial areas connected to median groove by very shallow depression; surface sculpture as in median groove.
Posterolateral angles with distinct impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous.
Metasternum without median glabrous area. Elytra: Length 1.00 mm; maximum width (near midlength) 0.72 mm. Disc
slightly rounded, moderately dull, with six rows of punctures between suture and humeri. Sides convex, declivity origin
near posterior 0.33; most punctures somewhat elongate; intervals rounded, width 0.50 puncture width; interstices between
punctures 0.25 puncture length; each puncture with seta. Explanate margin moderately developed. Abdomen: Basal five
sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short
hairs. Legs: All legs moderately long and slender; ratio of hind leg length to abdominal length 1.7/1.
Protarsomeres without suction setae. Genitalia: Male (Fig. 100D)(68 examined).

Variation. - The following variation was noted; 1) specimens from Baja California have a
median glabrous area on the metasternum; 2) pronotal sculpture reaches its smooth extreme in
specimens from San Benito County, California; and 3) some specimens from Oregon have the
elytra shorter than is commonly seen. The aedeagus of O. aberti Hatch (Fig. 100D) does not
differ significantly from other examples studied. A total of 692 specimens were examined (see
appendix).

Natural History. - O. interruptus has a rather wide ecological tolerance, populations living
at the margins of lotic, lentic, and brackish aquatic habitats. Habitat descriptors include “wet
edge of Clear Lake”, “farm pond”, “fresh pool, SE shore L. Abert”, and “margins of hot
springs”. Halophilic habits are indicated by such locality descriptors as “brackish pond”, “tide
pool”, “on mud, salt flat”, and “salt marsh”. I. Moore collected 276 specimens from a salt
marsh in Baja California, demonstrating that O. interruptus can achieve high population
densities in brackish water habitats.

Distribution. - (Figs. 101C,183). From southern British Columbia south through the
coastal mountains of Washington, Oregon and California to northern Baja California.

Remarks. - I have seen more instances of misidentifications involving O. interruptus than
any other previously described species in the genus.

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5. Ochthebius sierrensis new species
(Figs. 97D,99A,1 18C,183)

Type-locality. - Squaw Valley, Fresno County, California, U.S.A.

Type-specimens. - The holotype male and allotype, which have identical label data, are
deposited in CAS. They were collected by P.S. Bartholomew in 1955. Data about paratypes
(15) are listed in the appendix.

Figs. 102A - D, Aedeagi of Ochthebius attritus. (A) Monroe County, Florida. (B) Puerto Rico. (C) Pernambuco, Brazil
(drawn from holotype of O. schubarti d’Orchymont). (D) Barranquilla, Colombia.

Diagnosis. - Adults are easily confused with those of O. pacificus and O. arenicolus, having
the arcuate anterior pronotal margin, separate pronotal foveae and pubescent metasternum in
common. O. sierrensis adults differ in lighter color, presence of very small postocular
emarginations and especially aedeagal form. The aedeagus resembles that of O. californicus
and O. costipennis males, but externally O. sierrensis adults differ markedly from those two
species of the bisinuatus Group.

Description. — Ovate, slightly convex (Fig. 97D). Size: Holotype 1.36 mm long, 0.64 mm wide. Color: Dorsum and
venter dark brown; legs and palpi brown. Head: Length 0.26 mm; width 0.38 mm. Frons microreticulate, with moderate
size punctures and fine hairs, surface shiny; interocular foveae deep and large, width of each nearly 0.66 distance between
them; interocular tuberculi moderately large; basomedial fovea nearly as deep as interocular foveae, smaller. Frontoclypeal
suture evenly arcuate. Clypeus length 0.50 width; with small punctures, microreticulations, and fine hairs. Labroclypeal
suture straight. Labrum length 0.33 width; surface with fine punctures and fine, dense hairs; median emargination small,
with upturned edge, emargination obscured in habitus view. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4 0.50 length of 3. Mentum width equal length, moderately shining, with sparse, small punctures; anterior
margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely
punctulate. Thorax: Pronotum length at midline 0.34 mm; maximum width (near anterior 0.33) 0.50 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border origin near anterior 0.20 of lateral depression, extended arcuate to posterior angles, very narrow
around posterior margin. Anterior margin of pronotum arcuate, without crenulations in front of lateral fossulae and
without excavation in front of each lateral depression; anterior angles acute. Lateral depressions flat, microreticulate, with

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small hairs; margins moderately arcuate; pronotum moderately constricted behind lateral depressions. Lateral fossulae
moderately deeply impressed, with well developed microreticulation; inner margin abrupt, posterior extreme tapered into
lateral hyaline border. Pronotal disc moderately convex, punctures moderately small, separated by one-three times
puncture diameter; interpunctal areas with extremely fine, irregular impressions; with fine, sparse hairs. Median groove
moderately deep and wide, with uniform microreticulation; not extended to anterior and posterior margins. Anterior
foveae small, rather shallow ovals, connected to median groove by depression with well developed punctation. Posterior
foveae moderately large,oval, rather deep; posteromedial areas confluent with median groove; surface sculpture as in
median groove. Posterolateral angles with distinct impressions. Prosternum with median carina ended at coxal cavities;
coxae contiguous. Metasternum without median glabrous area. Elytra: Length 0.88 mm; maximum width (near
midlength) 0.64 mm. Disc flat, dull, with six rows of punctures between suture and humeri. Sides convex, declivity
origin near posterior 0.33; most punctures somewhat elongate; intervals flat, width equal puncture width; with irregular,
finely impressed lines; interstices between punctures 0.25 puncture length; each puncture with seta. Explanate margin
slightly developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50
glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg length to
abdominal length 1. 7:1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 1 18C)(6 examined).

Variation. - Specimens from Calaveras County have the transverse depressions joining the
pronotal foveae slightly less microreticulate than specimens from Fresno County.

Distribution. - (Figs. 99A,183). California, on the western slope of the Sierra Nevada
mountains.

Etymology. - The adjectival name, sierrensis, refers to the geographical distribution.

The borealis Subgroup

The borealis subgroup is characterized by broadly confluent posterior foveae not separated
by a well-defined median groove. Infrequently, as in O. lineatus adults, the anterior and
posterior foveae of a side are united to form a sinuate line (Fig. 103A).

A trend is apparent toward development (or possibly loss) of an enlargement of the median
portion of the aedeagus in lateral view. Males of four of the five species comprising the
subgroup have this feature. The enlargement reaches its maximum expression in males of O.
kaszabi, (Fig. 108A) but is quite evident in those of O. borealis (Fig. 110A), O. uniformis
(Fig. 110D) and O. lineatus , especially in males of the northern morph (Fig. 108D).

This subgroup has a northern distribution for the most part, with two species, O. kaszabi
and O. marinus being holarctic. O. lineatus is the only exception to the northerly restricted
pattern, being the most widespread species in the subgenus (Western Hemisphere members),
extending as far south as Colombia (Fig. 107).

6. Ochthebius lineatus LeConte
(Figs. 1 0C,98D-F,103A-F, 104,1 07, 1 08C,D, 1 19A, 184)

Ochthebius lineatus LeConte, 1852:211 (lectotype male in MCZ, here designated; type-locality: Colorado River,

California, U.S.A.).- LeConte, 1 855:361 . - LeConte, 1878:379. - Horn, 1 890:24. - Leech and Chandler, 1 956:333. -

Hatch, 1965:18.

Ochthebius milleri Hatch, 1965:18 (holotype male in UWA; type-locality: Sucker Creek Canyon, Malheur County,

Oregon, U.S.A.; new synonomy).

LeConte’s type-series includes three specimens, the second of which is without head and
prothorax. The first specimen, a male, is lectotype. LeConte (1852) in the original description
states that the specimen (s?) before him were from “Colorado”. In his later paper (1855),
however, he writes “Colorado River, California”, which agrees with the gold disc affixed to the
pin, his code for California. The specimen is light colored and quite metallic, as is typical of
southern morphs of this species (see section on variation). Hatch’s holotype has an aedeagus of

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an intermediate type between that of the southern and northern morph (Fig. 104-apex of
aedeagus from eastern Oregon was drawn from holotype of O. milleri Hatch).

Diagnosis. - Pronotal form (Fig. 103 A) with lateral areas of anterior and posterior foveae of
a side confluent to form a sinuate line and medial areas shallowly confluent to form a transverse
depression at each end of the median groove, together with the long lateral depressions and
glabrous area of the metasternum serve to distinguish adults of this species from others of
Ochthebius

Description. — Form: Ovate, moderately convex (Fig. 1 19A). Size: Lectotype 1.48 mm long, 0.72 mm wide. Color:
Head and pronotum brown; elytra, legs and venter slightly lighter. Head: Length 0.24 mm; width 0.40 mm. Frons finely
sparsely punctate in middle region, sides microreticulate; with very fine hairs; interocular foveae deep and large, width of
each nearly 0.66 distance between them; interocular tuberculi small but prominent; basomedial fovea small. Frontoclypeal
suture evenly arcuate. Clypeus length 0.50 width; with microreticulation and fine hairs. Labroclypeal suture straight.
Labrum length 0.33 width; surface with microreticulation and fine hairs; median emargination absent; anteromedial area
upturned to produce a small tooth. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.66 length of 3.
Mentum width equal length, shining, with small punctures; anterior margin arcuate. Submentum evenly, finely
punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline
0.34 mm; maximum width (near anterior 0.33) 0.50 mm. Anterior hyaline border moderately wide in front of disc, slightly
wider in front of lateral fossulae, then tapering to anterior angles. Lateral hyaline border origin near midlength of lateral
depression, extended slightly arcuate to posterior angles, very narrow around posterior margin. Anterior margin of
pronotum arcuate, without crenulations in front of lateral fossulae and without, excavation in front of each lateral
depression; anterior angles obtuse. Lateral depressions flat, microreticulate, sparsely, finely punctate, with small hairs;
margins moderately arcuate; pronotum slightly constricted behind lateral depressions. Lateral fossulae shallowly
impressed, with well developed microreticulation. Pronotal disc moderately convex, punctures in interfoveal area fine and
sparse, separated by two-five times puncture diameter; with fine, sparse hairs; microreticulation extremely slightly
developed; surface between punctures smooth and shiny. Median groove rather shallow, microreticulate. Anterior foveae
with abrupt lateral margins, medial margins connected by moderately deep, microreticulate depression. Posterior foveae
elongate, with abrupt lateral margins; posteromedial areas connected to median groove by shallow, microreticulate
depression; raised lateral areas of anterior and posterior foveae together in form of sinuate line. Posterolateral angles with
distinct impressions. Prosternum swollen in midline; coxae contiguous. Metasternal median glabrous area well developed.
Elytra: Length 0.96 mm; maximum width (near midlength) 0.72 mm. Disc flat, moderately shiny, with six rows of
punctures between suture and humeri. Sides convex, declivity origin near posterior 0.33; punctures round; intervals flat,
width equal puncture width, with fine impressed lines; interstices between punctures 0.50 puncture length; each puncture
with seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two
segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and slender; ratio of
hind leg length to abdominal length 2. 0:1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male

(Figs. 104, 108C,D)(140 examined); Female (Fig. 10C).

Variation. - This widely distributed species has a southern and northern geographical form
(Fig. 107). The southern morph ranges from Colombia north through mainland Central
America to approximately the Texas-Mexico border in the east, and the boundaries of the
Great Basin in the West. Adults are typically smaller, lighter colored, many are testaceous with
metallic reflections, and form of male genitalia is rather homogeneous throughout the range.
The northern morph occurs in western North America from southern Canada south to the
interface zone with the southern morph. Northern morph individuals are generally larger, dark
brown colored, and males have an aedeagus differing from that of the southern morph
(Figs. 104,108C,D). Variation in shape of the aedeagal apical piece is greater within the
northern morph population suggesting considerable subpopulational isolation. This
heterogeneity of aedeagal form in the northern morph results in a rather ill-defined interface
zone between the two morphs. Consequently, there is no discrete “geographic morphological
shift” composed of clinal intermediates between the two morphs. Therefore, I think the
population relationships of O. lineatus are more accurately reflected by a discussion of
“morphs”, and not formal subspecific designation.

Natural History. - This species has a wide ecological tolerance; samples were collected at
margins of streams, rivers, ponds (both permanent and temporary), lakes, swamps, and hot

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Figs. 103 A - F, Ochthebius lineatus, <3. (A) head and pronotum. (B) head, anterior view. (C) head, ventral view. (D)
labrum and associated mouthparts. (E) pro- and mesosternum. (F) labral emargination and sensilla.

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Fig. 104. Variation in the aedeagal apex of Ochthebius lineatus.

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springs. More unusual habitat descriptors include “rock crevice, tidewater”, “foul pool”,
“gravel pit”, and “alkalia water”.

Distribution. - Western North America, mainland Central america, and northern South
America (Figs. 107,184).

Remarks. - O. lineatus is the most frequently collected North American Ochthebius. I have
examined 1,690 specimens (see appendix).

7. Ochthebius marinus (Paykull)

(Figs. 105A,106A,B,108B,109,1 1 1H,184)

Elophorus marinus Paykull, 1798:245 (type depository undetermined). - d’Orchymont, 1943a: 12. - F. Balfour-Browne,
1958:163. -Janssens, 1967b:54.

Ochthebius holmbergi Maklin, 1852:74 (lectotype male in MCZ, here designated; type-locality: Kenai Peninsula, Alaska,
U.S.A.; new synonomy). - LeConte, 1855:362. - LeConte, 1878:379. - Horn, 1890:24. - Leech and Chandler,
1956:333.- Hatch, 1965:18.

Depository of the holotype of O. marinus is unknown. My concept is based upon specimens in
the Institut royal des Sciences Naturelles de Belgique (Brussels) and in the British Museum
(Natural History) (London) determined by A. d’Orchymont and J. Balfour-Browne,
respectively. The aedeagi of these males have been removed and studied; they are clearly of the
form illustrated by d’Orchymont (1943a, p. 1 4) for O. marinus. Further research is necessary to
find the holotype of this species.

The type-series of Ochthebius holmbergi Maklin in the LeConte collection at the MCZ
consists of six specimens. The first is a male which has been dissected to remove the aedeagus;
it is clearly of the O. marinus form. This specimen is lectotype of O. holmbergi. LeConte had
informed Alexander Agassiz of the MCZ in a letter (Darlington, 1961) that part of his
collection, which he was donating, contained specimens from Maklin’s collection. For this
reason I feel the specimen here selected as lectotype, which is from the type-locality (Kenai
Peninsula), was one of the syntypes before Maklin at the time of his original description.

Diagnosis. - Certain individuals of this species are externally very similar to O. kaszabi , but
are distinguished by the metasternum which is glabrous in at least the posterior 0.50 of the
median area in O. marinus and totally hydrofuge pubescent or glabrous in the extreme
posterior 0.20 in O. kaszabi. Additionally, most O. kaszabi adults have the elytral intervals
more elevated and the pronotum more deeply sculptured (Figs. 106A-D). The extremely
dissimilar male genitalia (Figs. 108A,B) provide the most reliable means of separation. Refer
to the sections on variation for further comment.

Description. — Form: Elongate-oval, moderately convex (Fig. 105A). Size: Approximately 1.84 mm long, 0.80 mm i
wide. Color: Dorsum dark brown, venter slightly darker; palpi and elytral epipleura slightly lighter. Head: Length
0.32 mm; width 0.46 mm. Frons slightly elevated in midline, with microreticulation, punctures twice size of
microreticulation, microreticulation nearly absent from elevated midregion, but well developed anterior to elevation;
surface shiny, with very fine hairs; interocular foveae deep and large, width of each nearly 0.66 distance between them;
interocular tuberculi moderately large; basomedial fovea nearly as deep as interocular foveae, smaller. Frontoclypeal
suture evenly arcuate. Clypeus length 0.50 width; microreticulation and punctures as on frons, with fine hairs.
Labroclypeal suture straight. Labrum length slightly less than 0.33 width; surface with microreticulation and fine,
moderately dense hairs; median emargination absent, entire anterior margin very slightly arcuate to posterior. Maxillary
palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of 3. Mentum width equal length, moderately shining,
with sparse, small punctures; anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae
shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.42 mm; maximum width (near
anterior 0.33) 0.60 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae,
then tapered to anterior angles. Lateral hyaline border origin near midlength of lateral depression, extended straight to

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Figs. 105A - C, Ochthebius body outlines. (A) O. marinus. (B) O. uniformis. (C) O. kaszabi.

posterior angles, very narrow around posterior margin. Anterior margin of pronotum arcuate, without crenulations in
front of lateral fossulae and without excavation in front of each lateral depression; anterior angles obtuse. Lateral
depressions long, 0.75 length of pronotum, flat in anterior 0.50, slightly convex in posterior 0.50; microreticulate and
punctate, with small hairs; margins arcuate; pronotum slightly constricted behind lateral depressions. Lateral fossulae
deeply impressed, with well developed microreticulation; inner margin abrupt, posterior extreme tapered into lateral
hyaline border. Pronotal disc moderately convex, punctures small and sparse, separated by three-six times puncture
diameter; with fine, sparse hairs; surface between punctures smooth and shiny. Median groove absent from posterior
0.50, anterior 0.50 united to confluent anterior foveae as deeply impressed T-shape, interior with well developed
microreticulation. Posterior foveae with abrupt lateral margins; posteromedial areas confluent; together the confluent
foveae in form of deeply impressed, broad U-shape, interior microreticulate. Posterolateral angles with with distinct
impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median
glabrous area. Elytra: Length 1.20 mm; maximum width (near midlength) 0.80 mm. Disc flat, moderately dull, with six
rows of punctures between suture and humeri. Sides convex, declivity origin near posterior 0.33; most punctures quite
small, round and closely set; intervals slightly rounded, width equal puncture width; interstices between punctures 0.25
puncture length; each puncture with seta. Explanate margin weakly developed. Abdomen: Basal five sterna with
hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs:
Moderately long and slender; ratio of hind leg length to abdominal length 2. 0:1.0. Protarsomeres 1-3 with suction setae.
Genitalia: Male (Fig. 108B)(41 examined).

Variation. - Coloration of many adults is very distinctive: head and pronotum are dark
brownish, frequently with bluish reflections, which contrast with the testaceous elytra, palpi
and legs. Some specimens, however, are primarily brown without these attractive contrasting
color differences. The area between median groove and confluent posterior foveae varies
considerably, from very broad, equaling length of the median groove, to very narrow. Some

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Figs. 106A - F, Ochthebius structures. (A) O. marinus , pronotum. (B) O. marinus , elytral striae and intervals. (C) O.
kaszabi, pronotum (arrows indicate pronotal sensilla). (D) O. kaszabi , elytral striae and intervals. (E) O. borealis ,
pronotum. (F) O. borealis, pronotal microsculpture.

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321

specimens with the very narrow condition have a slight depression joining the median groove to
the confluent posterior foveae; however, the microreticulation of the groove and that of the
foveae are not contiguous. The glabrous area of the metasternum occupies approximately the
posterior 0.50 of the metasternum, although some specimens have a number of hairs within the
otherwise glabrous area. This latter condition appears in specimens from various localities and
no discrete geographical trends were observed. I have examined 702 specimens (see appendix).

Natural History. - Judging from locality data (see appendix) it appears that O. marinus is
primarily a pond species with some halophilous tendencies.

Distribution. - (Figs. 109,184). Western North America: southern limits are the southern
areas of California, Nevada, Utah and Colorado; northern limits are Churchill, Manitoba in
the east and Kenai Peninsula, Alaska in the west.

8. Ochthebius uniformis new species
(Figs. 105B,1 10D,1 17C,184)

Type-locality. - San Francisco, California, U.S.A.

Type-specimens. - The holotype male and allotype, which have identical locality data, are
deposited in CAS. They were collected by F.E. Blaisdell in 1909. Data about paratypes (80) are
presented in the appendix.

Diagnosis. - The following combination of characteristics renders this species quite distinct
from the other members of the borealis Subgroup: 1) black color, 2) somewhat convex form,
with moderately deflexed head, 3) oval posterior foveae, lacking abrupt lateral extremes and, 4)
extremely uniform microreticulation of pronotal foveae and lateral areas.

Description. — Form: Ovate, moderately convex (Fig. 105B). Size: Holotype 1.76 mm long, 0.80 mm wide. Color:
Dorsum and venter very dark brown, nearly black; legs and palpi brown. Head: Length 0.30 mm; width 0.46 mm. Frons
slightly elevated and very shiny in midline; microreticulatate and punctate, punctures five times size of microreticulation
pattern; microreticulation absent from elevated midregion, but well developed anterior to elevation and in lateral areas;
with fine, sparse hairs; interocular foveae deep and large, width of each nearly 0.66 distance between them; interocular
tuberculi large; basomedial fovea nearly as deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate.
Clypeus length 0.50 width; with microreticulation in posterior 0.50, anterior 0.50 shiny, with sparse, fine punctures; with
fine hairs. Labroclypeal suture straight. Labrum length 0.33 width; surface with microreticulation and fine, moderately
dense hairs; median emargination absent, entire anterior margin slightly arcuate to rear, with very slightly elevated edge in
midline. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of 3. Mentum width equal length,
shining, with sparse, small punctures; anterior margin arcuate. Submentum evenly, finely punctulate, punctures
contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.42 mm; maximum
width (near anterior 0.33) 0.60 mm. Anterior hyaline border rather narrow in front of disc, slightly wider in front of lateral
fossulae, then tapered to anterior angles. Lateral hyaline border origin near anterior 0.33 of lateral depression, extended
slightly arcuate to posterior angles, very narrow around posterior margin. Anterior margin of pronotum arcuate, without
crenulations in front of lateral fossulae and without excavation in front of each lateral depression; anterior angles obtuse.
Lateral depressions flat, broad and long, extended 0.80 length of pronotum; with distinctive microreticulation and very
sparse small hairs; very small tooth at posterior extreme; margins arcuate, pronotum very slightly constricted behind.
Lateral fossulae shallowly impressed, with well developed microreticulation; inner margin abrupt, posterior extreme
tapered into lateral hyaline border. Pronotal disc moderately convex, punctures moderately small, separated by one-three
times puncture diameter; with fine, sparse hairs; surface between punctures smooth and shiny. Median groove in middle
0.25 of pronotum only, very shallow, microreticulate; anterior and posterior extremes obliterated by markedly confluent
foveae. Anterior foveae broadly and deeply confluent, united to median groove in form of T, microreticulate. Posterior
foveae broadly oval, with lateral and anterior 0.50 of medial margins equally abrupt; posteromedial areas broadly
confluent; entire depressed area distintly microreticulate. Posterolateral angles with distinct impressions. Prosternum with
median carina ended at coxal cavities; coxae contiguous. Metasternum with well developed median glabrous area. Elytra:
Length 1.16 mm; maximum width (near midlength) 0.80 mm. Disc flat, moderately dull, with six rows of punctures
between suture and humeri. Sides convex, declivity origin near posterior 0.33; most punctures round, small; intervals
rounded, width equal puncture width, with fine impressed lines; interstices between punctures 0.25 puncture length; each
puncture with seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence.
Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and

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slender; ratio of hind leg length to abdominal length 1.8: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male
(Fig. 110D)(25 examined).

Variation. - The connection between the median groove and posterior foveae, as indicated
by contiguity of microreticulation of the respective areas, is evident in all specimens. The
metasternal glabrous area is well developed, occupying at least the posterior 0.50 of the
metasternum.

Natural History. - Adults have been collected in many coastal ponds. H.B. Leech collected
a specimen from “Dillon Beach, pools, foot of Sand Point Dunes”. Other collectors reported
“pond near beach” (542 specimens), “Whale Beach”, “Point Reyes Peninsula ”, “Siltcoos
Beach” and other descriptors indicating halophilic habits (see appendix).

Distribution. - (Figs. 1 1 7C, 1 84). Coastal ponds of Washington, Oregon and California.
One inland locality known: Fish Lake, Steens mountains, eastern Oregon (B. Malkin).

Etymology. - Latin, unus (one) plus formus (form). Named in reference to the uniform
microreticulation of the pronotum.

9. Ochthebius borealis new species
(Figs. 97F, 1 06E,F, 1 1 OA-C, 1 1 1 D-F, 1 1 7C, 1 84)

Type-locality. - Pool in stream, grassy slope, 4.5 miles S. of Mendocino Pass, 6500 feet,
NW corner Glenn County, California, U.S.A.

Type-specimens. - The holotype male and allotype are deposited in CAS and have identical
locality data. They were collected by Hugh B. Leech, July 29, 1960. Data about paratypes
(362) are presented in the appendix.

Diagnosis. - Within the borealis Subgroup, O. borealis adults are distinguished by abrupt,
elevated lateral extremes of the posterior foveae (Figs. 106E,F), black color and aedeagal form.

Description. — Form: Ovate, moderately convex (Fig. 97F). Size: Holotype 2.00 mm long, 0.80 mm wide. Color:
Dorsum and venter black; legs and palpi dark brown. Head: Length 0.36 mm; width 0.50 mm. Frons microreticulate, with
moderately small punctures, surface shiny; interocular foveae deep and large, width of each nearly 0.66 distance between
them; interocular tuberculi large; basomedial fovea nearly as deep as interocular foveae, smaller. Frontoclypeal suture
evenly arcuate. Clypeus length 0.50 width; microreticulation very uniform and hairs fine, very sparse. Labroclypeal suture
straight. Labrum length 0.33 width; microreticulate, punctures moderately small; hairs fine, dense; median emargination
absent, entire anterior margin slightly arcuate to rear and very slightly upturned. Maxillary palpus with palpomere 3
moderately wide; palpomere 4 nearly 0.66 length of 3. Mentum width equal length, moderately shining, microreticulate
with randomly spaced punctures about equal in size to four microreticulation elements: anterior margin arcuate.
Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax:
Pronotum length at midline 0.44 mm; maximum width (near anterior 0.33) 0.70 mm. Anterior hyaline border moderately
wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border
origin near midlength of lateral depression, extended slightly arcuate to posterior angles, very narrow around posterior
margin. Anterior margin of pronotum arcuate, without crenulations in front of each lateral depression; anterior angles
obtuse. Lateral depressions flat, broad and long, extended across 0.75 length of pronotum; small tooth at posterior extreme;
with distinctive microreticulation and very sparse, small hairs; margins arcuate; pronotum slightly constricted behind
lateral depressions. Lateral fossulae rather shallowly impressed, with well developed microreticulation; inner margin
abrupt, posterior extreme tapered into tooth at lateral hyaline border. Pronotal disc slightly convex, interfoveal areas with
very uniform microreticulation and very sparse, fine hairs; surface dull. Median groove shallow depression connected with
markedly confluent anterior and posterior foveae, microreticulate. Anterior foveae broadly confluent, with ditinctive
microreticulation; lateral margin of each fovea delimited by oblique carina. Posterior foveae with lateral margins abrupt,
straight, oblique lines; posteromedial areas broadly confluent; entire depression with microreticulation. Posterolateral
angles with distinct impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum
with well developed median glabrous area. Elytra: Length 1.28 mm; maximum width (near midlength) 0.88 mm. Disc flat,
moderately dull, with six rows of punctures between suture and humeri. Sides convex, declivity origin near posterior 0.33;
most punctures round; intervals rounded, width equal puncture width; with fine impressed lines; interstices between
punctures 0.50 puncture length; each puncture with seta. Explanate margin moderately developed. Abdomen: Basal five
sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short

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Fig. 107. Geographical distribution of Ochthebius lineatus (stippled area indicates intergrade zone of northern and
southern morphs).

hairs. Legs: Moderately long and slender; ratio of hind leg length to abdominal length 1.7: 1.0. Protarsomeres.1-3 with
suction setae. Genitalia: Male (Figs. 100A-C)(75 examined).

Variation. - Development of pronotal microreticulation varies clinally, with an increase in
microreticulation from north to south. Related to decrease in microreticulation of northern
specimens is reduction in development of the median groove. The latter connects broadly with
the confluent posterior foveae in specimens from Baja California, and the microreticulation of
the two depressions is contiguous. This condition is lessened somewhat in specimens from
northern California, although microreticulation of the median groove and posterior foveae is
contiguous. Specimens from British Columbia, however, have the median groove separated
from the confluent posterior foveae, and microreticulation of the two areas lack contiguity.

There are corresponding differences in genitalia of specimens from the three areas
(Figs. 1 10A-C). Those of the southern form appear to be more similar to the central form than

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Figs. 108A - D, Aedeagi of Ochthebius species. (A) O. kaszabi, Yukon Territory, Canada. (B) O. marinus , Bottineau
County, North Dakota, (C) O. lineatus , Riverside County, California. (D) O. lineatus. Cassia County, Idaho.

(insets: apices rotated slightly)

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325

the latter is to the northern form. This similarity may indicate a greater rate of gene flow
between the central and southern populations. However, this may be a reflection of inadequate
sampling in the areas between the central and northern populations. In either event, based upon
the genitalic differences between other species, I have no doubt that the northern form is
conspecific with the central and southern forms. The male labrum also displays clinal variation,
with members of most southern populations having the anterior border upturned along its entire
width (Fig. 11 IE); the central populations with generally only the middle region slightly
upturned; and the northern populations very slightly upturned in the middle region, or not at
all. All specimens of O. borealis have the glabrous metasternal area well developed, occupying
at least the posterior 0.50 of the metasternum.

Natural History. - Locality data indicate that O. borealis members live in both ponds and
streams, but not in halophilic situations.

Distribution. - (Figs. 1 1 7C, 1 84). Western North America; eastern and southern limits
roughly formed by a line drawn through British Columbia, Colorado and Baja California.

Etymology. - Latin, borealis (northern). I refer to the geographical distribution.

10. Ochthebius kaszabi Janssens
(Figs. 92A,105C,106C,D,108A,1 1 1G,184)

Ochthebius kaszabi Janssens, 1967b:56 (holotype male deposited in HNHM; type-locality: Mongolia, Bajachongor aimak,

Tujn gol, 1250 m., bei somon Bogd).

Dr. Z. Kaszab of the Hungarian Natural Histroy Museum, Budapest, loaned me the
putative holotype of O. kaszabi. However, data on labels attached to the specimen do not
correspond to any of that given by Janssens (1967b) for O. kaszabi. The specimen has five
labels as follows (diagonal lines indicate different labels): /Mongolia, Bajanchongor aimak,
Tujn gol, 1250 m. bei somon Bodg Exp. Dr. Z. KASZAB, 1964/Nr. 195 25-VI-1964/ Prep.
Micr. No. 816511/ TYPE (red label)/ E. Janssens det., 1965, Ochthebius sensu stricto kaszabi
n. sp./. Janssens (1967b), however, cites this locality in data for O. marinus , O. evanescens and
O. mongolicus (and it is certainly possible that all four species were collected at a single
locality).

Furthermore, the aedeagus on microslide which bears the preparation number
corresponding to that on the label attached to the holotype (“Prep. Micr. No. 816511”) is the
aedeagus of O. subaeneus Janssens (1967b), and is indicated as such on the microslide label
(this microslide is deposited in HNHM). Dr. Kaszab informs me (in litt .) that this microslide
plus one additional microslide (which I have seen - it has also the aedeagus of O. subaeneus)
arc the only microslides available in the Hungarian Museum collection.

In a 1978 visit to the Institut royal des Sciences de Belgique, I searched for additional
microslides with aedeagi which corresponded to that illustrated by Janssens (1967b) for O.
kaszabi , and located two such slide-mounted aedeagi.

Amongst this confusion one point remains paramount: the aedeagus of O. kaszabi illustrated
by Janssens is unique and quite distinctive. To resolve this confusion, I removed the coverslip of
one of the microslide mounts which has an O. kaszabi aedeagus, and placed this aedeagus in a
microvial and attached same to the pin bearing the holotype. This may or may not be the
aedeagus of the holotype, but it is certainly the aedeagus of an O. kaszabi specimen from
Mongolia; it differs only very slightly from aedeagi of specimens of O. kaszabi from North
America.

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Fig. 109. Geographical distribution of Ochthebius marinus (Kenai Peninsula, Alaska, locality omitted).

Diagnosis. - Refer to the diagnosis of O. marinus and to the variation discussions of both
species.

Description. — Form: Elongate-oval, moderately convex (Fig. 105C). Size: Length 1.80 mm; width 0.44 mm.
Color: Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.30 mm; width 0.44 mm. Frons slightly
elevated, with microreticulation within punctures; latter dense, some confluent; with very fine hairs; interocular foveae
deep and large, width of each nearly 0.66 distance between them; interocular tuberculi large; basomedial fovea nearly as
deep and as large as interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with
microreticulation and fine hairs. Labroclypeal suture straight. Labrum length 0.33 width; surface with microreticulation
and fine hairs; median emargination absent, entire margin slightly arcuate to rear. Maxillary palpus with palpomere 3
moderately wide; palpomere 4 0.50 length of 3. Mentum width equal length, shining, with microreticulation and small
punctures; anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen.
Postgena finely punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near anterior 0.33) 0.60 mm.
Anterior hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior
angles. Lateral hyaline border origin near midlength of lateral depression, extended straight to posterior angles, very
narrow around posterior margin. Anterior margin of pronotum arcuate, without crenulations in front of lateral fossulae
and without excavation in front of each lateral depression; anterior angles obtuse. Lateral depressions flat, broad and long,
extended across 0.75 length of pronotum, with microreticulation, irregular punctures, and small hairs; margins moderately
arcuate; pronotum slightly constricted behind lateral depressions. Lateral fossulae moderately deeply impressed, with well

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Figs. 110A - D, Aedeagi of Ochthebius species. (A) O. borealis holotype, Glenn County, California. (B) O. borealis,
British Columbia, Canada. (C) O. borealis, Baja California, Mexico. (D) O. uniformis, holotype (inset: apex rotated
slightly).

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developed microreticulation; inner margin abrupt, posterior extreme tapered into lateral hyaline border. Pronotal disc
moderately convex, punctures in interfoveal area moderately small, separated by one-three times puncture diameter;
with fine, sparse hairs; surface between punctures smooth and shiny. Median groove confluent in anterior 0.50 with
deeply confluent anterior fovea in form of T-shaped depression with well developed microreticulation; posterior 0.50 of
median groove absent, posterior foveae deeply confluent. Latter with abrupt lateral margins; posteromedial areas
broadly confluent with median groove in form of wide U-shaped depression with well developed microreticulation.
Posterolateral angles with distinct impressions. Prosternum with median carina ended at coxal cavities; coxae
contiguous. Metasternum without median glabrous area. Elytra: Length 1.20 mm; maximum width (near midlength)
0.80 mm. Disc flat, moderately dull, with six rows of punctures between suture and humeri. Sides convex, declivity
beginning near posterior 0.33; punctures round; intervals rounded, moderately elevated, width equal puncture width,
with fine impressed lines; interstices between punctures 0.25 puncture length; each puncture with seta. Explanate
margin slightly developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal
0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg length to
abdominal length 1.7: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 108A)(37 examined).

Variation. - The connection between the median groove and confluent posterior foveae, as
indicated by the contiguity of the microreticulation of the two areas, varies from moderately
developed to entirely absent, although the former condition predominated in the specimens
studied. Extremes occur within single series, illustrating that this condition is unrelated to
geographic considerations. Range of variation in development of the pronotal median groove
makes it virtually impossible to distinguish certain specimens of O. marinus and O. kaszabi on
the basis of these features. The metasternum of O. kaszabi adults is either entirely pubescent,
or only the posterior 0.20 is glabrous. The glabrous metasternal area of O. marinus adults
occupies at least the posterior 0.50 of the metasternum. This character plus moderately
elevated elytral intervals of O. kaszabi and flat intervals of O. marinus (Figs. 106B,D) serve to
distinguish the two species, as do the male genitalia (Figs. 108A,B).

A long series of specimens from Churchill, Manitoba ( 1 0-VIII- 1937, W.J. Brown collector)
contained both O . kaszabi and O. marinus. Adults of both species were at their character
extremes, thus it was quite easy to distinguish one group from the other on the basis of pronotal,
elytral, color and size differences in addition to genitalic features. Perhaps this indicates some
degree of character displacement acting upon these two species.

I have studied a total of 286 specimens of O. kaszabi (see appendix).

Natural History. - Most of the locality data for this species do not specify lotic or lentic
habitats, although a few “lake”, “pond” and “spring” citations are present (see appendix). I
have collected O. kaszabi adults from the sand-gravel margin of a moderately rapid stream in
British Columbia.

Distribution. - (Figs. 92A,184). Mongolia and northern North America.

The rectus Subgroup

Shape of the lateral pronotal depressions, which are nearly parallel to one another anteriorly
and are markedly arcuate posteriorly (Fig. 96 A), serves to characterize the three members of
this subgoup.

This subgroup lives in western United States, with one species ( O . rectus ) widely
distributed, one ( O . rectusalsus ) restricted to saline coastal areas, and one ( O . recticulus)
restricted to the Wilbur Hot Springs area of Colusa County, California.

Habitat data indicate that members of this group are facultative halophiles.

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1 1 . Ochthebius rectus LeConte
(Figs. 96A,101D,1 1 1 A-C,l 12E,1 13A,B,182A)

Ochthebius rectus LeConte, 1878:379 (holotype female in MCZ; type-locality: Fort Tejon, Kern County, California,

U.S.A.). - Horn, 1890:21. - Fall, 1901:213. - Fall, 1919:212. - Brown, 1933:45. - Leech and Chandler, 1956:333. -

Hatch, 1965:19.

Diagnosis. - Form of the lateral pronotal depressions, which are parallel anteriorly and
markedly arcuate posteriorly, broad lateral hyaline borders extended to the anterior angles, and
the oblong body form (Figs. 96A,112E) serve as diagnostic characteristics for O. rectus. Refer
to the diagnoses of O. recticulus and O. rectusalsus for a comparison with those species.

Description. — Form: Oblong, slightly depressed (Fig. 1 12E). Size: Holotype 2.12 mm long, 0.96 mm wide. Color:
Dorsum and venter black; legs and palpi dark brown. Head: Length 0.34 mm; width 0.52 mm. Frons slightly elevated,
finely, moderately densely punctate, slightly microreticulate laterally; interocular foveae deep and large, width of each
equal to distance between them; interocular tuberculi large; basomedial fovea nearly as deep as interocular foveae, smaller.
Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with dense, fine punctures and fine sparse hairs.
Labroclypeal suture straight. Labrum length 0.33 width; surface with microreticulation and fine hairs; median
emargination absent, entire margin slightly arcuate to rear. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4, 0.50 length of 3. Mentum width equal length, shining, with microreticulation and small punctures; anterior
margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely
punctulate. Thorax: Pronotum length at midline 0.48 mm; maximum width (near anterior 0.33) 0.76 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border broad, origin at anterior angles, extended arcuate to posterior angles, very narrow around posterior
margin. Anterior margin of pronotum very slightly bisinuate, without crenulations in front of lateral fossulae and without
excavation in front of each lateral depression; anterior angles acute. Lateral depressions convex, broad and long, extended
0.75 length of pronotum, with microreticulation, irregular punctures, and small hairs; margins arcuate, rounded at
posterior, not excavate; pronotum constricted behind lateral depressions. Lateral fossulae moderately deeply impressed,
with well developed microreticulation; inner margin abrupt, posterior extreme tapering into lateral hyaline border.
Pronotal disc moderately convex, punctures in interfoveal area moderately small and dense, separated by 0.5- 1.0 times
puncture diameter; with fine, sparse hairs; surface between punctures smooth and shiny. Median groove narrow channel
with microreticulation. Anterior foveae well developed, width equal to distance between each fovea from median groove;
internally microreticulate. Posterior foveae well developed, oblique, with well developed microreticulation. Posterolateral
angles with distinct impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum
without median glabrous area. Elytra: Length 1.46 mm; maximum width (near midlength) 0.96 mm. Disc slightly convex,
moderately shiny, with six rows of round punctures between suture and humeri. Sides convex, declivity origin near
posterior 0.33; intervals rounded, very slightly elevated, width 0.50 puncture width; interstices between punctures 0.25
puncture length; each puncture with seta. Explanate margin slightly developed. Abdomen: Basal five sterna with
hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs:
Moderately long and slender; ratio of hind leg length to abdominal length 1.8: 1.0. Protarsomeres 1-3 without suction setae.
Genitalia: Male (Figs. 1 13A,B)(53 examined).

Variation. - Specimens studied range in length from 1 .60 to 2.20 mm. The aedeagus varies
as illustrated (Figs. 113A,B); no significant external variation was noted which correlated with
these genitalic variants. A total of 453 specimens were examined (see appendix).

Natural History. - Locality data indicate that O. rectus is halophilic and thermophilic, with
many specimens taken at the saline margins of desert hot springs. Habitat descriptors include
“at edge of hot spring”, “small waterhole on alkaline flat”, “Salt Creek”, “salt marsh”,
“Badwater, Death Valley”, “Saratoga Spring, Death Valley”, “saline pool”, “alkaline
irrigation ditch”, and “muck, hot spring temp. 90 degrees F.”.

Distribution. - (Figs. 101D,182A). Western North America; from Vancouver Island,
British Columbia south to southern Califormia and east to Wyoming. Greatest population
density in the arid regions of California.

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Figs. 1 1 1A - H, Oehthebius structures. (A) O. rectus 2, ventral surface of labrum. (B) O. rectus 3, ventral surface of
labrum. (C) O. rectus 2, labral sensilla. (D) O. borealis 3, labral emargination. (E) O. borealis 3, labrum, dorsal aspect.
(F) O. borealis 3, anterior aspect of head. (G) O. kaszabi 6, labrum, dorsal aspect. (FI) O. marinus 3, labrum, dorsal
aspect.

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12. Ochthehius rectusalsus new species
(Figs. 101E,1 12F,1 14A,182A)

Type-locality. - Tide pool, Albany, Contra Costa County, California, U.S.A.

Type-specimens. - Holotype male and allotype with identical locality data are in CAS.
These specimens were collected by C.T. Dodds, February 8, 1921. Data about paratypes (52)
are presented in the appendix.

Diagnosis. - The broader form, coarser pronotal punctation, denser pronotal pubescence,
brown color and aedeagal form serve to distinguish adults of this species from those of the very
similar O. rectus (Figs. 1 12E,F,1 13B,1 14A).

Description. — Form: Ovate, moderately convex (Fig. 1 12F). Size: Holotype 1.80 mm long, 0.82 mm wide. Color:
Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.32 mm; width 0.46 mm. Frons slightly elevated,
coarsely densely punctate, some microreticulation evident anteriorly and laterally, sparsely pubescent; interocular foveae
deep and large, width of each equal to distance between them; interocular tuberculi large; basomedial fovea nearly as deep
as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width, densely coarsely punctate,
sparsely pubescent. Labroclypeal suture straight. Labrum length 0.33 width; surface with microreticulation and fine hairs;
median emargination absent, entire margin slightly arcuate to rear. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4 0.50 length of 3. Mentum width equal length, shining, with microreticulation and small punctures; anterior
margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely
punctulate. Thorax: Pronotum length at midline 0.44 mm; maximum width (near anterior 0.33) 0.70 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border broad, origin at anterior angles, extended very arcuate to posterior angles, very narrow around
posterior margin. Anterior margin of pronotum straight, with small crenulations in front of lateral fossulae; without
excavation in front of each lateral depression; anterior angles right. Lateral depressions convex, broad and long, extended
across 0.75 length of pronotum, microreticulation within punctures, punctures coarse, dense; pubescence sparse; margins
arcuate, evenly rounded at posterior, not excavate; pronotum constricted behind lateral depressions. Lateral fossulae
deeply impressed, with well developed microreticulation; inner margin abrupt, posterior extreme tapered into lateral
hyaline border. Pronotal disc moderately convex, quite hairy; punctures in interfoveal area coarse, dense, microreticulate,
separated by 0.50 puncture diameter; with prominent, dense hairs; ridges between punctures smooth and shiny. Median
groove narrow, deeply impressed, internally microreticulate, impunctate. Anterior foveae obscured by dense, coarse
punctures, this area shallowly depressed. Posterior foveae moderately deep, with dense, coarse punctures. Posterolateral
angles with distinct impressions. Prosternum with low ridge ended at coxal cavities; coxae contiguous. Metasternum with
very small median glabrous area anterior to hind coxae. Elytra: Length 1.24 mm; maximum width (near midlength)
0.82 mm. Disc convex, moderately dull, with six rows of punctures between suture and humeri. Sides convex, declivity
beginning near posterior 0.33; punctures round, intervals rounded, very slightly elevated, width 0.50 puncture width;
interstices between punctures 0.25 puncture length; each puncture with seta. Explanate margin slightly developed.
Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with
very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg length to abdominal length 1.9: 1.0.
Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 1 1 4A)( 1 8 examined).

Variation. - No significant differences were noted in the specimens studied.

Natural History. - This species is halophilic, as indicated by the following habitat
descriptors: “tide pool”, “mud, salt flat”, “salt marsh”, “Moss Landing”, and “salt ponds”.
Among Western Hemisphere Hydraenidae, only Neochthebius vandykei is definitely known to
be intertidal. Further study may indicate that O. rectusalsus is also capable of maintaining
populations in habitats which are submerged at high tide.

Distribution. - (Figs. 101E,182A). Coastal, from San Francisco bay area, California, south
to Baja California, Mexico. One specimen known from the coast of Washington.

Etymology. - rectus plus Latin salsus (salted). Named in reference to the halophilic habits
and external similarity to O. rectus.

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13. Ochthebius recticulus new species
(Figs. 101E,112D,113C,182A)

Type-locality. - Wilbur Springs, elevation 1250 feet, Colusa County, California, U.S.A.

Type-specimens. - The holotype and allotype with identical locality data are in USNM. I
collected these specimens July 17, 1971. Data about paratypes (143) are presented in the
appendix.

Diagnosis. - Small size, limited distribution and male genitalia (Figs. 112D,113C) serve to
distinguish O. recticulus adults from those of its closest relatives, O. rectusalsus and O. rectus.

Description. — Form: Elongate-oval, moderately depressed (Fig. 11 2D). Size: Holotype 1.56 mm long, 0.72 mm
wide. Color: Dorsum black; venter, legs and palpi dark brown. Head: Length 0.26 mm; width 0.40 mm. Frons with dense,
large punctures, some confluent; microreticulation moderately developed laterally, less so medially; hairs well developed;
interocular foveae deep and large, width of each nearly 0.66 distance between them; interocular tuberculi large;
basomedial fovea nearly as deep and as large as interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus length
0.50 width; with well developed microreticulation and fine hairs. Labroclypeal suture straight. Labrum length 0.33 width;
surface with microreticulation and fine hairs; median emargination absent. Maxillary palpus with palpomere 3 moderately
wide; palpomere 4 0.50 length of 3. Mentum width equal length, shining, with microreticulation and small punctures;
anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near anterior 0.33) 0.58 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border origin at anterior angles, extended very arcuate to posterior angles, very narrow around posterior
margin. Anterior margin of pronotum straight, with small crenulations in front of lateral fossulae; without excavation in
front of each lateral depression; anterior angles acute. Lateral depressions convex, broad, with large dense punctures and
well developed hairs; margins arcuate; pronotum quite constricted behind lateral depressions. Lateral fossulae deeply
impressed, with well developed microreticulation; inner margin abrupt, posterior extreme tapered into lateral hyaline
border. Pronotal disc moderately convex, punctures large, deep and dense, in some specimens confluent and with internal
microreticulation; form of foveae partially obscured by large size and density of punctures; hairs well developed. Median
groove slightly developed in anterior and posterior; middle region obscured by large punctures. Posterior foveae without
abrupt margins, partially obscured by large punctures. Anterior foveae very slightly developed, nearly totally obscured by
punctation. Posterolateral angles with shallow impressions. Prosternum with very weakly developed median carina ended
at coxal cavities; coxae contiguous. Metasternum without median glabrous area. Elytra: Length 1 .08 mm; maximum width
(near midlength) 0.72 mm. Disc slightly convex, dull, with six rows of large round punctures between suture and humeri.
Sides convex, declivity origin near posterior 0.33; punctures round; intervals rounded, subcostate, width equal to 0.50
puncture width; interstices between punctures thin walls; each puncture with seta. Explanate margin slightly developed.
Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with
very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg length to abdominal length 1.5: 1.0.
Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 1 13C)(23 examined).

Variation. - Specimens available are quite homogeneous in external characteristics.

Natural History. - I collected more than 100 specimens from one section of shoreline
bordering the creek at Wilbur Hot Springs. The water was warm to the touch and, presumably,
the ultimate reason for abundance of these beetles and other aquatic insects observed. The
single specimen known from outside the hot spring area was collected only nine miles away.

Distribution. - (Figs. 101E,182A). Known only from Wilbur Hot Springs area, Colusa
County, California.

Etymology. - rectus plus Latin ulus (diminutive suffix). I refer to the small size and
similarity to O. rectus.

Remarks. - I am grateful to Hugh B. Leech for suggesting that this locality might be
interesting, and for providing directions.

The bisinuatus Group

This group is characterized by the bisinuate anterior pronotal margin. Generally speaking,

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Figs. 1 1 2A - F, Ochthebius body outlines. (A) O. alpinopetrus . (B) O. tubus. (C) O. spanglerorum. (D) O. recticulus. (E)
O. rectus. (F) O. rectusalsus.

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Figs. 1 1 3 A - C, Ochthebius aedeagi. (A) O. rectus , variation in aedeagal apex. (B) O. rectus , San Benito County,
California. (C) O. recticulus , holotype.

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Figs. 1 14A - E, Aedeagi of Ochthebius species. (A) O. rectusalsus , holotype. (B) O. bisinuatus, holotype (inset (top to
bottom): Harvey County, Oregon; Plumas County, California; Alberta, Canada; Custer County, Idaho). (C) O. crenatus.
Lake County, Oregon. (D) O. crenatus , holotype. (E) O. richmondi , holotype.

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most of these species are small, roughly sculptured and genitalically conservative.

Geographically the group is found in the western United States and adjacent Canada, with
most specimens in the Pacific Coast states and all of the six presently included members with at
least part of their range in California.

14. Ochthebius bisinuatus new species
(Figs. 101F,1 14B,1 15A-E,1 16F,181 A)

Type-locality. - Trinity River at Big Flat, Trinity County, California, U.S.A.

Type-specimens. - Holotype male and allotype, which have identical locality data, are
deposited in CAS. They were collected by Hugh B. Leech, August 4, 1960. Data about
paratypes (478) are listed in the appendix.

Diagnosis. - Within the bisinuatus Group, males of this species are distinguished by
aedeagal form and lack of the following external modifications characteristic of other species of
the group: crenate pronotum, costate elytra and broad hyaline borders which attain the anterior
pronotal angles (Figs. 1 15A-E).

Description. — Form: Ovate, moderately convex (Fig. 1 16F). Size: Holotype 1.52 mm long, 0.68 mm wide. Color:

Head and pronotum dark brown with slight copperish and bluish reflections, remainder lighter brown. Head: Length
0.30 mm; width 0.40 mm; Frons with fine microreticulation and shallow, slightly larger punctures randomly spaced,
moderately dull, with very fine, indistinct hairs; interocular foveae deep and large, width of each nearly 0.66 distance
between them; interocular tuberculi large and distinct; basomedial fovea nearly as deep as interocular foveae, smaller.
Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with punctation and hairs as on frons. Labroclypeal suture
straight. Labrum length 0.33 width; surface with fine microreticulation and dense hairs; median emargination moderately
deep and wide, depth nearly 0.33 length of labrum, width 0.20 width of labrum, edge very slightly upturned; lobes at angle
to remainder of labrum. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 nearly 0.50 length of 3.
Mentum width and length equal, anterior margin deeply arcuate to rear; surface very smooth and shiny, with shallow,
small punctures. Submentum evenly, finely punctulate, punctures contiguous. Genae dull, swollen. Postgena finely
punctulate. Thorax: Pronotum length at midline 0.36 mm; maximum width (at anterior 0.33) 0.52 mm. Anterior hyaline j

border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral
hyaline border origin near anterior 0.33 of lateral depression, extended slightly arcuate to posterior angles, very narrow ;

around posterior margin. Anterior margin of pronotum distinctively bisinuate, with very small irregularities in front of
lateral fossulae and without shallow excavation in front of each lateral depression; anterior angles acute. Lateral
depressions flat, with fine microreticulation and small indistinct hairs; margins markedly arcuate, pronotum apparently |
constricted behind lateral depressions. Lateral fossulae with inner margin abrupt, posterior extreme tapered into lateral
hyaline membrane. Pronotal disc convex, with extremely uniform, fine microreticulation; hairs not apparent. Median '

groove deep, wide, slightly constricted in posterior 0.50, nearly extended to anterior and posterior margins; surface
sculpture as on disc. Anterior foveae moderately shallow, connected to median groove by shallow depression; lateral
margin straight, elevated ridge. Posterior foveae oval, elongate and oblique, length slightly greater than twice width, width
twice that of median groove; surface sculpture as on disc; lateral margins abrupt, all other margins indistinct.
Posterolateral angles with distinct impressions. Prosternum elevated in midline but without obvious carina; coxae
contiguous. Metasternum with glabrous area restricted to posterior 0.20; surface with very fine, dense punctures. Elytra:
Length 1.00 mm; maximum width (near midlength) 0.68 mm. Disc moderately flat, moderately dull, with six rows of
punctures between suture and humeri. Sides convex, declivity origin near posterior 0.33; most punctures slightly elongate;
intervals flat, with fine irregular lines, width 1.50 puncture diameter; interstices between punctures 0.25 puncture length;
each puncture with a very small seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge
pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Of moderate
build and length; ratio of hind leg length to abdominal length 1.9: 1.0. Protarsomeres 1-3 with suction setae. Genitalia:

Male (Fig. 1 14B)(67 examined).

Variation. - Northern specimens tend to be slightly darker, have the glabrous metasternal
area larger, and have the microreticulation somewhat reduced (resulting in a more reflective
pronotal disc). Specimens from California form a recognizable group characterized by
microreticulation more markedly developed than most specimens from the remainder of the
range. This section of California, from the San Francisco bay area to the California-Oregon
border, is the only area of sympatry of O. bisinuatus and O. californicus. The latter is the

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337

Figs. 1 15A - E, Ochthebius bisinuatus. (A) head and pronotum. (B) labral emargination and sensilla, anterior view. (C)
head, anterior view. (D) labral emargination and sensilla, oblique view. (E) labrum, dorsal view.

species most closely similar to O. bisinuatus. Development of microreticulation of
non-Californian specimens of O. bisinuatus more closely approximates that of O. californicus,
and perhaps character displacement is acting upon the California population of O. californicus
to produce a greater development of the microreticulation, especially that of the pronotum. If
so, texture of the pronotum must be involved in species recognition.

Some specimens of O. bisinuatus from Alberta, near the known northern distributional
limit, have the following features which differ from the holotype: 1) nearly black in color; 2)
prosternal carina present, 3) glabrous area of metasternum well developed, 4) microreticulation
reduced, surface more reflective; 5) median groove constricted in middle, 6) anterior foveae not
connected to median groove by a shallow depression; 7) median extremes of posterior foveae
distinct and 8) elytral punctures slightly larger, less elongate. Despite these differences there is

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a general similarity in body shape and most other characters, including the male genitalia
(Fig. 1 14B), and I have no doubt that these differences are expressions of semi-clinal variation
within the species. The one specimen (male) I have seen from the easternmost known locality,
Natrona Co., Wyoming, compares more closely with specimens from the northern extreme of
the distribution than with those from the southern extreme, further indication of isolation of the
southern population. Females are very similar to males, but lack protarsal suction setae and
labral lobes are not at an angle to the remainder of the labrum.

Distribution. - (Figs. 101 F, 181 A). Principally a species of the United States Pacific
Northwest, but ranging as far south as central California, as far north as British Columbia, and
as far east as central Wyoming.

Etymology. - Latin bi (two) plus sinuatus (curve). Named in reference to the bisinuate
anterior margin of the pronotum.

15. Ochthebius californicus new species
(Figs. 10B,1 16D,1 17B,1 18D,181A)

Type-locality. - Kern river, 9.5 road miles N. of Kernville, Tulare County, California,
U.S.A.

Type-specimens. - The holotype male and allotype, which have identical locality data are
deposited in CAS. Hugh B. Leech collected them March 25, 1970. Data about paratypes (116)
are presented in the appendix.

Diagnosis. - Small size, rugulose pronotum, bisinuate anterior pronotal margin with
crenulations behind the eyes, and the broad lateral hyaline borders which attain the anterior
angles of the pronotum serve as diagnostic features for this rather distinctive species. Refer to
the section on variation for a comparison with O. bisinuatus.

Description. — Form: Slightly truncate, convex (Fig. 1 16D). Size: Holotype 1.41 mm long, 0.61 mm wide. Color:
Entire body dark brown, moderately reflective. Head: Length 0.28 mm; width 0.38 mm. Frons with dense, deep,
moderately large punctures, some punctures subconfluent, surface moderately shining, with fine hairs; interocular foveae
deep and large, width of each equal to distance between them; interocular tuberculi small, indistinct; basomedial fovea
nearly as deep as interocular foveae, smaller. Frontoclypeal suture bisinuate. Clypeus length 0.50 width; with fine
microreticulation and fine, sparse hairs. Labroclypeal suture straight. Labrum length 0.33 width; surface somewhat
rugulose, with fine, sparse hairs; median emargination moderately deep and somewhat narrow, depth nearly 0.33 length of
labrum, width nearly 0.25 width of labrum; lobes upturned. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4 nearly 0.50 length of penultimate. Mentum square, shining, with small punctures separated by puncture
diameter. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate.
Thorax: Pronotum length at midline 0.34 mm; maximum width (at anterior 0.25) 0.54 mm. Anterior hyaline border
moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline
border origin at anterior angles, divergent from pronotum in anterior 0.25, thence extended arcuate to posterior angles,
narrow around posterior margin. Anterior margin of pronotum distinctly bisinuate, with crenulations in front of lateral
fossulae and very shallow excavation in front of each lateral depression; anterior angles acute. Lateral depressions flat,
somewhat rugulose, with small indistinct hairs; margins markedly arcuate, pronotum constricted behind lateral
depressions. Lateral fossulae with inner margin abrupt, posterior extreme tapered into lateral hyaline border. Pronotal disc
convex, punctures moderately large, quite close together and irregular in size, surface moderately rugulose; with fine short
hairs. Median groove deep, wide, slightly constricted in middle 0.50, nearly extended to anterior and posterior margins;
surface sculpture as on disc. Anterior foveae deep, suboval, subconfluent with median groove punctures very dense,
confluent in some specimens; lateral margin straight and nearly parallel to median groove; median margin arcuate.
Posterior foveae oval, elongate and oblique, length slightly greater than twice width, width slightly greater than width of
median groove; surface sculpture as on disc; lateral margin abrupt, posterior extremes indefinite. Posterolateral angles with
distinct impressions. Prosternal carina ended at coxal cavities; coxae contiguous. Metasternum with median glabrous area
well developed, extended nearly full length of metasternum, triangular; surface with moderately large punctures, most
punctures separated by puncture diameter. Elytra: Length 0.98 mm. maximum width (near midlength) 0.70 mm. Disc
convex, moderately dull, with six rows of punctures between suture and humeri. Sides convex, declivity beginning near
posterior 0.33; most punctures round; intervals flat, width equal to puncture diameter; interstices between punctures 0.25

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puncture diameter; each puncture with very small, indistinct seta. Explanate margin moderately developed. Abdomen:
Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very
fine, short hairs. Legs: Of moderate build and length; ratio of hind leg length to abdominal length 1.6: 1.0.
Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 1 1 8D)(23 examined); female (Fig. 10B).

Variation. - Slight variation is exhibited. Some specimens have the pronotal sculpture very
slightly coarser than the average. Females lack protarsal suction setae and do not have the
labral lobes upturned. O. californicus is most closely similar to O. bisinuatus, and one who is
unfamiliar with this group might experience some difficulty in differentiating some specimens
of the two species. In general, O. californicus adults are slightly more robust, the pronotal hairs
are slightly more apparent, and the surface is obviously more markedly sculptured than O.
bisinuatus adults. More specifically, the lateral hyaline border of the pronotum has its anterior
extreme at or very near the anterior angles in O. californicus , whereas it is near the anterior
0.33 of the lateral depressions in O. bisinuatus. Development of crenulations in front of the
lateral fossulae are also of use, being more readily apparent in O. californicus. The male
genitalia of the two species are easily distinguished (Figs. 114B,118D). Refer to the variation
section of O. bisinuatus for comments on specimens from the area of sympatry of the two
species.

Distribution. - (Figs. 117B,181A). Distributed throughout California; one locality known
from Carson City in westernmost Nevada.

Etymology. - Named after the geographical distribution.

16. Ochthebius richmondi new species
(Figs. 1 14E,1 16E,1 17B,181 A)

Type-locality. - Mad River 4 miles N. of Areata, N. Bank road, Humboldt County,
California, U.S.A.

Type-specimens. - The holotype male and allotype, which have identical locality data are
deposited in CAS. Hugh B. Leech collected these specimens, October 1, 1965. Data about
paratypes (117) are presented in the appendix.

Diagnosis. - I have not found any constant and distinctive sculptural differences between O.
richmondi and its most closely similar relative, O. bisinuatus. However, larger size, 1.80 mm
versus 1.68 mm, the deep black color, and form of the male genitalia (Figs. 114B,E) are
diagnostic features.

Description. — Form: Elongate oval, moderately convex (Fig. 1 16E). Size: Holotype 1.80 mm long, 0.84 mm wide.
Color: Dorsum and venter black, legs and palpi brown; moderately shiny, with faint brassy reflections on pronotum. Head:
Length 0.32 mm; width 0.48 mm. Frons microreticulate, punctures separated by their diameters, some elevated areas
shining; with very fine, sparse hairs; interocular foveae deep and large, width of each equal to distance between them;
interocular tuberculi moderately large, shining; basomedial fovea nearly as deep as interocular foveae, smaller.
Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with fine microreticulation, without obvious hairs.
Labroclypeal suture straight. Labrum length 0.50 width; surface with microreticulation and fine, sparse hairs; median
emargination of moderate depth and width, depth 0.33 length of labrum, width 0.25 width of labrum, edge slightly
upturned. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 nearly 0.50 length of 3. Mentum nearly
square, with anterior margin arcuate to rear; with moderately large punctures separated by two-three times puncture
diameter. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate.
Thorax: Pronotum length at midline 0.40 mm; maximum width (at anterior 0.20) 0.62 mm. Anterior hyaline border
moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline
border origin near anterior 0.33 of lateral depression, extended nearly straight to posterior angles, very narrow around
posterior margin. Anterior margin of pronotum bisinuate, without crenulations in front of lateral fossulae; without shallow
excavation in front of lateral depression; anterior angles obtuse. Lateral depressions flat, dull, punctate and
microreticulate, with small indistinct hairs; margins strongly arcuate, pronotum constricted behind lateral depressions.
Lateral fossulae with abrupt inner margin, posterior extreme tapered into lateral hyaline border. Pronotal disc convex.

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Figs. 1 16A - F, Ochthebius body outlines. (A) O. crassalus. (B) O. crenatus. (C) O. costipennis. (D) O. californicus. (E)
O. richmondi. (F) O. bisinuatus.

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341

with distinctive microreticulation, punctures separated by puncture diameter; moderately shining; with fine, sparse,
indistinctive hairs. Median groove moderately deep and wide, anterior 0.50 slightly wider than posterior; surface
sculpture as on disc. Anterior foveae moderately deep, elongate oval, width of fovea slightly less than median groove,
area between fovea and groove shallow depression equal to width of groove; lateral margin straight and nearly parallel
to median groove; median margin indistinct. Posterior foveae oval, elongate and oblique, length slightly greater than
twice width, width twice that of narrowest portion of median groove; surface sculpture as on disc; lateral margins
abrupt, posterior extremes indefinite. Posterolateral angles with distinct impressions. Prosternum with very low carina
ended at coxal cavities; coxae contiguous. Metasternum with median glabrous area moderately developed, suboval,
restricted to posterior 0.50 of metasternum; surface with dense, fine punctures and sparse, fine hairs. Elytra: Length
1.24 mm; maximum width (near midlength) 0.84 mm. Disc moderately flat, moderately dull, with six rows of punctures
between suture and humeri. Sides convex, declivity beginning near posterior 0.33; most punctures round; intervals flat,
width slightly greater than puncture diameter; interstices between punctures 0.50 puncture diameter; each puncture
with very small seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence.
Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and
slender; ratio of hind leg length to abdominal length 2. 0:1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male
(Fig. 1 14E)( 16 examined).

Variation. - Specimens from the three known localities compare quite favorably. Females
lack protarsal suction setae and do not have the labral lobes upturned.

Distribution. - (Figs. 1 1 7B, 181 A). Known from one locality in western Washington and two
in northern California.

Etymology. - I take pleasure in dedicating this species to the late E.A. Richmond in
recognition of his contributions to the knowledge of hydraenid and hydrophilid larvae.

Remarks. - The series of 14 specimens from King County, Washington contained two
specimens of O. bisinuatus.

17. Ochthebius costipennis Fall
(Figs. 1 16C,1 17A,1 18B,181 A)

Ochthebius costipennis Fall, 1901:214 (holotype male in MCZ; type-locality: Ventura, California, U.S.A.). - Leech and

Chandler, 1956:333).

Diagnosis. - The small size, approximately 1.30 mm long, rather broad form, and especially
the costate elytral intervals are distinctive adult features of this rare species. Male genitalia and
external characteristics are most similar to O. californicus, but there are very distinctive
differences, including: 1) costate versus non-costate elytral intervals, 2) different pronotal
shape, with O. costipennis having the lateral hyaline borders beginning near midlength of the
lateral depressions whereas they begin at the anterior angles of the pronotum in O. californicus
(Figs. 116C,D), and 3) different pronotal sculpture, O. costipennis having moderately large,
discrete punctures and smooth punctural interstices on the disc whereas O. californicus has
microreticulate punctural interstices in this area.

Description. — Form: Truncate, convex (Fig. 116C). Size: Holotype 1.32 mm long, 0.60 mm wide. Color: Body
uniformly dark brown, moderately reflective. Head: Length 0.24 mm; width 0.36 mm. Frons with dense, deep, moderately
large punctures, some punctures subconfluent, surface moderately shining, without obvious hairs; interocular foveae deep
and large, width of each nearly 0.66 distance between them; interocular tuberculi small, indistinct; basomedial fovea
nearly as deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with dense,
deep, moderately large punctures as on frons, without obvious hairs. Labroclypeal suture evenly arcuate. Labrum length
nearly 0.33 width; surface somewhat rugulose, with fine, sparse hairs; median emargination moderately deep and
somewhat narrow, depth nearly 0.33 length of labrum, width 0.20 width of labrum, edge very slightly upturned. Maxillary
palpus with palpomere 3 moderately wide; palpomere 4 nearly 0.50 length of 3. Mentum wider than long, moderately
shining, with dense, deep, small punctures. Submentum evenly, finely punctulate, punctures contiguous. Genae shining,
swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.34 mm; maximum width (at approximately
midlength)0.51 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae,
then tapered to anterior angles. Lateral hyaline border origin near midlength of lateral depression, extended slightly
arcuate to posterior angles, very narrow around posterior margin. Anterior margin of pronotum very shallowly bisinuate,
with crenulations in front of lateral fossulae and very shallow excavation in front of lateral depression; anterior angles

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Figs. 1 17A - C, Geographical distributions of Ochthebius species. (A) O. costipennis • , O. crenatus ★ and O. crassalus
A (B) O. calif ornicus • and O. richmondi ★ . (C) O. borealis • and O. uniformis A •

obtuse. Lateral depressions convex, with large distinct punctures and small indistinct hairs; margins markedly arcuate,
pronotum apparently constricted behind lateral depressions. Lateral fossulae wide, 0.50 width of lateral depression,
deeply impressed, inner margin abrupt, posterior extreme tapered into lateral hyaline border. Pronotal disc convex,
punctures moderately large, quite uniform, separated by puncture diameter; hairs not apparent; surfaces between
punctures flat and smooth, but only moderately shiny. Median groove deep, wide, slightly constricted in middle 0.50,
nearly extended to anterior and posterior margins; surface sculpture as on disc. Anterior foveae deep, suboval; width of
fovea, median groove and area between them all approximately equal; lateral margin straight and nearly parallel to
median groove; median margin arcuate. Posterior foveae oval, elongate and oblique, length slightly greater than twice
width, width slightly greater than width of median groove; surface sculpture as on disc; all margins equally abrupt.
Posterolateral angles with distinct impressions. Prosternum carinate; coxae contiguous. Prosternum with median carina
ended near anterior 0.33. Metasternum with median glabrous area well developed, extended full length of metasternum,
subrhomboidal; surface with moderately large punctures, most punctures separated by puncture diameter. Elytra:
Length 0.86 mm; maximum width (near midlength) 0.62 mm. Disc convex, moderately dull, with six rows of punctures
between suture and humeri. Sides convex, declivity extreme, origin near midlength; most punctures round; intervals
costate, width 0.50 puncture diameter; interstices between punctures 0.25 puncture diameter; each puncture with very
small, indistinct seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence.
Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, long hairs. Legs: Stout and short; when
hind femur is at right angle to the midline tarsus extends to abdominal apex. Genitalia: Male (Fig. 1 1 8B)( 1 examined).

Variation. - The few specimens studied (11) were rather homogeneous.

i/ 1-

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Distribution. - (Figs. 117A,181A) Known only from the coastal mountains between San
Francisco and Ventura, California.

Remarks. - Male genitalia and habitus illustrated are drawn from a specimen collected at
Lompoc, Santa Barbara County, California. They compare very closely with those aspects of
the holotype.

18. Ochthebius crenatus Hatch
(Figs. 1 14C,D,1 16B,1 17A,181A)

Ochthebius crenatus Hatch, 1965:18 (holotype male in UWA; type-locality: Boville, Idaho, U.S.A.).

Diagnosis. - The crenulate pronotal disc serves to readily distinguish adults of the rare O.
crenatus from those of all other New World Ochthebius. The elytra are also very distinctive,
being quite convex and with large, deeply impressed punctures.

Description. — Form: Truncate, very convex (Fig. 1 16B). Size: Holotype 1.40 mm long, 0.72 mm wide. Color:
Dorsum dark brown, nearly black; venter dark brown; moderately dull. Head: Length 0.28 mm; width 0.42 mm. Frons
with dense punctures of varied sizes, some punctures subconfluent, surface moderately shining, with numerous short hairs;
interocular foveae deep and large, width of each equal to distance between them; interocular tuberculi distinct; basomedial
fovea nearly as deep and as wide as interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width;
microreticulate and punctate, punctures variously spaced, with numerous short hairs. Labroclypeal suture evenly arcuate.
Labrum length nearly 0.50 width; surface somewhat rugulose, with fine, sparse hairs; median emargination moderately
deep and wide, depth 0.33 length of labrum, width 0.33 width of labrum, edge very slightly upturned. Maxillary palpus
with palpomere 3 moderately wide; palpomere 4 nearly 0.50 length of 3. Mentum square, moderately shining, with dense,
small punctures. Submentum evenly, finely punctulate, punctures contiguous. Genae dull, swollen. Postgena finely
punctulate. Thorax: Pronotum length at midline 0.38 mm; maximum width (at approximately midlength)) 0.58 mm.
Anterior hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapering to
anterior angles. Lateral hyaline border origin near anterior 0.20 of lateral depression, extended arcuate to posterior angles,
very narrow around posterior margin. Anterior margin of pronotum very shallowly bisinuate, with small produced area in
front of lateral fossulae and distinctive excavation in front of lateral depression; anterior angles acute. Lateral depressions
flat, slightly rugulose, without distinct hairs; margins markedly arcuate, pronotum constricted behind lateral depressions.
Lateral fossulae with outer margin tapered into lateral depression, inner margin abrupt, posterior extreme tapering into
lateral hyaline border. Pronotal disc markedly convex, with dense deep punctures, surface crenulate; hairs not apparent;
surfaces between punctures elevated ridges. Median groove deep, wide, slightly constricted in middle 0.50, nearly extended
to anterior and posterior margins; surface sculpture as on disc. Anterior foveae deep, subtriangular, lateral margin an
elevated ridge, median extreme confluent with median groove. Posterior foveae oval, elongate and oblique, length twice
width, width slightly greater than width of median groove; surface sculpture as on disc; lateral margins elevated as
irregular ridge. Posterolateral angles with distinct impressions. Prosternum with median carina ended at coxal cavities;
coxae contiguous. Metasternum with median glabrous area well developed, extended full length of metasternum,
subrhomboidal; surface with moderately large punctures, most punctures separated by three times puncture diameter.
Elytra: Length 1.00 mm. maximum width (near midlength)) 0.74 mm. Disc convex, moderately dull, with six rows of
punctures between suture and humeri. Sides convex, declivity extreme, beginning near midlength; most punctures round;
intervals flat, width 0.50 puncture diameter; interstices between punctures 0.25 puncture diameter or less; each puncture
with a distinct appressed seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge
pubescence; pubescence very sparse in midline. Apical two segments smooth, midline and basal 0.50 glabrous, lateral,
apical areas with very fine, short hairs. Legs: Stout and short; when hind femur is at right angle to the midline tarsus
extends to posterior margin of abdominal segment 6. Protarsi without obvious suction setae. Genitalia: Male
(Figs. 1 14C,D)(3 examined); female (Fig. 10D).

Variation. - The few specimens studied (19) were rather homogeneous.

Distribution. - (Figs. 117A,181A). Northern California, southern Oregon and northern
Idaho.

19. Ochthebius crassalus new species
(Figs. 1 16A,1 17A,1 18A,181 A)

Type-locality. - Ventura County, California, U.S.A.

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Figs. 1 1 8 A - D, Aedeagi of Ochthebius holotypes. (A) O. crassalus. (B) O. costipennis. (C) O. sierrensis. (D) O.
californicus.

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345

Type-specimen. - The holotype male (unique) is deposited in CAS. It was collected by
F.E. Winters (date unknown).

Diagnosis. - The deeply sculptured pronotum, with its large median groove and foveae,
gives to adults of this species a quite different appearance from those of the other members of
the bisinuatus Group. The lateral depressions are quite convex and end abruptly at the
posterior, resulting in a very unusual, thickened appearance. Elytral punctures are deeply
impressed, large and round. These large punctures give the intervals a very irregular, somewhat
zig-zag appearance. The intervals are not costate (Fig. 1 16A).

Description. — Form: Truncate, convex (Fig. 1 16A). Size: Holotype 1.20 mm long, 0.64 mm wide. Color: Entire
body uniformly dark brown, moderately reflective. Head: Length 0.24 mm; width 0.36 mm.Frons with dense, deep,
moderately large punctures, some punctures subconfluent, surface moderately shining, with short hairs; interocular foveae
deep and large, width of each equal to distance between them; interocular tuberculi small, indistinct; basomedial fovea
nearly as deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; rugulose,
with numerous fine hairs. Labroclypeal suture evenly arcuate. Labrum length nearly 0.50 width; surface somewhat
rugulose, with fine, dense hairs; median emargination shallow and somewhat narrow, depth nearly 0.25 length of labrum,
width 0. 1 7 width of labrum, edge very slightly upturned. Maxillary palpus with palpomere 3 moderately wide; palpomere 4
nearly 0.50 length of 3. Mentum square, moderately shining, with dense, deep, small punctures. Submentum evenly, finely
punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline
0.36 mm; maximum width (at lateral depressions) 0.52 mm. Anterior hyaline border moderately wide in front of disc,
slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin near anterior 0.33
of lateral depression, extended nearly straight and undulating to posterior angles, very narrow around posterior margin.
Anterior margin of pronotum very shallowly bisinuate, with very small crenulations in front of lateral fossulae and very
shallow excavations in front of each lateral depression; anterior angles obtuse. Lateral depressions convex, with large
distinct punctures and small indistinct hairs; posterior area very convex, appearing inflated; margins very markedly
arcuate, pronotum greatly constricted behind lateral depressions. Lateral fossulae wide, 0.50 width of lateral depression,
deeply impressed, inner margin abrupt, posterior extreme arching ventrad to meet lateral hyaline border. Pronotal disc
very convex, punctures moderately large, separated by puncture diameter; hairs sparse; surfaces between punctures flat
and smooth, but only moderately shiny. Median groove very deep, wide, slightly constricted in posterior 0.50, nearly
extended to anterior and posterior margins; surface sculpture as on disc. Anterior foveae deep, suboval, width of fovea
equal to median groove; area separating median groove from fovea 0.50 width of fovea; lateral margin straight and nearly
parallel to median groove; median margin arcuate. Posterior foveae oval, elongate and oblique, length slightly greater than
twice width, width slightly greater than width of median groove; surface sculpture smoother than that on disc; all margins
equally abrupt. Posterolateral angles with distinct impressions. Prosternum carinate, carina ended at coxal cavities; coxae
contiguous. Metasternum with median glabrous area well developed, extended full length of metasternum, subrhomboidal;
surface with moderately large punctures, most punctures separated by puncture diameter. Elytra: Length 0.84 mm;
maximum width (near midlength) 0.64 mm. Disc subconvex, moderately dull, with six rows of punctures between suture
and humeri. Sides convex, declivity extreme, beginning near posterior 0.33; most punctures round; intervals flat, width
0.50 puncture diameter; interstices between punctures 0.25 puncture diameter or less; each puncture with distinct seta.
Explanate margin weakly developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth,
basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Stout and short; when hind femur is at right angle to
midline tarsus extends to abdominal apex. Protarsi without obvious suction setae. Genitalia: Male (Fig. 1 1 8 A)( 1
examined); female unknown.

Distribution. - (Figs. 117A,181A). Known only from the type-locality, Ventura County,
California.

Etymology. - Latin crassus (thickened) plus alus (wing). I refer to the lateral depressions
of the pronotum which extend prominently to the side, as “wings”, and which are distinctively
thickened at their posterior margins.

The biincisus Group

Members of this group have the anterior pronotal margin with more or less developed
postocular emarginations and postocular processes, and the metasternum is entirely pubescent.

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The pronotal features, in known species, reach their maximum expression in O. mexcavatus
(Fig. 128 A).

The group presently consists of 13 species and is found throughout Mexico and in the
western United States. Two major subdivisions of the group are evident. One subdivision
centers around O. sculptoides and has the pronotal pubescence slightly more prominent, dorsal
surface generally duller and lateral depressions more convex. The other subdivision centers
around O. biincisus and has the pronotal pubescence reduced, dorsal surface generally more
reflective and lateral depressions flat. Certain species, however, have intermediate forms of this
or that character. Consequently, I have not designated subgroups.

The most unusual morphological feature in a member of this group is the totally pubescent
fifth abdominal sternum of O. aztecus. No other species of Ochthebius (sensu stricto) in the
Western Hemisphere has this segment hydrofuge pubescent. In all other respects O. aztecus fits
well within the biincisus Group, therefore I am considering the structure of abdominal segment
5 of little phylogenetic significance.

20. Ochthebius attritus LeConte
(Figs. 92A,102A-D,1 19C,180)

Ochthebius attritus LeConte, 1878:380 (holotype female in MCZ; type-locality: Haulover, Florida, U.S.A.). - Horn,
1890:23. - d’Orchymont, 1943:47. - Young, 1954:206.

Ochthebius simplex LeConte, 1878:380 (holotype female in MCZ; type-locality: Haulover Florida, U.S.A.). - Horn,
1890:23.- Young, 1954:206.

Ochthebius schubarti d’Orchymont, 1943:47 (holotype male in ISNB; type-locality: Pernambuco, Brazil; new synonomy).

D’Orchymont’s type does not differ significantly from LeConte’s. The aedeagal form

(Fig. 102C) is within limits of variation seen in this species.

Diagnosis. - Distinguished from other species in the interruptus Subgroup by the following
combination of characteristics: 1) metasternum with large median glabrous area; 2) pronotum
with prominent postocular processes and continuous median groove; and 3) testaceous color
with metallic reflections. Very similar in both external and genitalic features to adults of O.
batesoni Blair from the Galapagos Islands, but O. attritus has a circum-Caribbean-Gulf of
Mexico distribution.

Description. — Form: Ovate, weakly convex (Fig. 119C). Size: Holotype 1.64 mm long, 0.68 mm wide. Color:
Pronotum brown with faint bluish and coppery reflections; elytra lighter brown than pronotum, nearly testaceous; head
dark brown; venter brown; legs, palpi and antennae testaceous. Head: Length 0.30 mm; width 0.42 mm. Frons slightly
elevated, with fine, irregularly spaced punctures; lateral areas microreticulate; interocular foveae deep and large, width of
each equal to distance between them; interocular tuberculi large; basomedial fovea nearly as deep and as large as
interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with well developed microreticulation
and fine hairs. Labroclypeal suture straight. Labrum length 0.33 width; surface with microreticulation and fine hairs;
anterior margin upturned in midline in form of small tooth. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4 0.50 length of 3. Mentum width equal length, shining, with microreticulation and small punctures; anterior
margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely
punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near anterior 0.33) 0.56 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border origin near anterior 0.33 of lateral depressions, extended straight to posterior angles, very narrow
around posterior margin. Anterior margin of pronotum straight in middle 0.50, slightly arcuate to rear in front of lateral
fossulae; small excavation in front of each lateral depression, median to which is a small tooth; anterior angles acute.
Lateral depressions convex, with fine, dense punctures; margins weakly arcuate, an extremely small tooth at posterior
extreme; pronotum appearing slightly constricted behind lateral depressions. Lateral fossulae moderately deeply
impressed, with well developed microreticulation; inner margin abrupt, posterior extreme tapered into small tooth at
lateral hyaline border. Pronotal disc moderately convex, punctures in interfoveal area moderately small, irregularly spaced,
some confluent; with fine, sparse hairs; surface between punctures smooth and shiny. Median groove in anterior connected

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Figs. 1 1 9 A - H, Ochthebius body outlines. (A) O. lineatus. (B) O. aztecus. (C) O. attritus. (D) O. batesoni. (E) O.
mesoamericanus. (F) O. sculptus. (G) O. sculptoides, Yavapai County, Arizona. (H) O. sculptoides, Stanislaus County,
California.

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Figs. 120A - E, Aedeagi of Ochthebius species. (A) O. aztecus, lectotype (inset: apex rotated slightly). (B) O. aztecus,
Durango, Mexico. (C) O. aztecus , Chapingo, Mexico, Mexico. (D) O. aztecus, San Bernardino County, California. (E) O.
sculptus, San Bernardino County, California.

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to anterior foveae by shallow transverse depression; posterior 0.50 of median groove absent; posterior foveae deeply
confluent; latter with abrupt lateral margins; posteromedial areas broadly confluent in form of wide U-shaped
depression with well developed punctation and microreticulation. Posterolateral angles with distinct impressions.
Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with well developed median
glabrous area. Elytra: Length 1.08 mm; maximum width (near midlength)0.68 mm. Disc flat, moderately shiny with six
rows of punctures between suture and humeri. Sides convex, declivity origin near posterior 0.33; punctures round;
intervals rounded, not elevated, width equal puncture width, with some surface irregularities; interstices between
punctures 0.25 puncture length; each puncture with seta. Explanate margin slightly developed. Abdomen: Basal five
sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short
hairs. Legs: Moderately long and slender; ratio of hind leg length to abdominal length 1.8: 1.0. Protarsi without suction
setae. Genitalia: Male (Figs. 102A-D)(1 1 examined).

Variation. - O. attritus exhibits a moderate degree of variation in pronotal sculpture. Most
populations, including Floridian, Mexican and Puerto Rican, have the posterior foveae and
posterior portion of the median groove joined by a shallow depression. However, the median
groove and foveae are distinct from one another. The specimens I have studied from Colombia,
in contrast, have the posterior foveae and median groove narrowly confluent and pronotal
sculpture slightly coarser in general. The smooth extreme of pronotal sculpture is seen in
specimens from Brownsville, Texas. The male genitalia (Figs. 102A-D) also vary, with the
Floridian, Colombian and Brazilian populations closely similar, whereas specimens from Puerto
Rico apparently form another subpopulation. The external features of the Puerto Rican
specimens, however, are closely similar to those of specimens from the other subpopulations.
Males differ from females in that the former have protarsal pads of suction setae and have the
anteromedial margin of the labrum upturned to form a small tooth. Females have the labral
anterior margin straight and not upturned, and lack protarsal pads. A total of 635 specimens
were studied (see appendix).

Natural History. - Locality data and geographical distribution indicate facultative
halophilic habits for O. attritus. Many specimens have been collected in brackish or even salt
water habitats. Sometimes large numbers of specimens are taken at a single site; Flint and
Spangler collected 480 at Playa Salina near Corozo, Puerto Rico (“in salt water”). The single
specimen known from the Yucatan Peninsula was found “beneath debris on seashore”.

Distribution. - (Figs. 92A,180). Antilles and mainland coastal areas of the Gulf of Mexico
and the Caribbean Sea. Also known from one locality in easternmost Brazil.

21. Ochthebius batesoni Blair
(Figs. 1 19D,143D,180)

Ochthebius batesoni Blair, 1933:473 (holotype female deposited in BMNH; type-locality: Franklin Lake, James Island,

Galapagos Islands).

Diagnosis. - Very similar and closely related to O. attritus , O. batesoni differs in aedeagal
form (Figs. 102A-D,143D), and body shape, which is generally more paralled-sided and
elongate than O. attritus (Figs. 119C,D). Refer to the diagnosis of O. attritus for further
comments.

Description. — Form: Elongate, moderately convex (Fig. 119D). Size: Holotype 1.64 mm long, 0.72 mm wide.
Color: Head and venter dark brown; legs, elytra and pronotum testaceous, the latter with faint metallic reflections. Head:
Length 0.26 mm; width 0.42 mm. Frons with small, dense punctures, surface shining, hairs prominent; interocular foveae
deep and large, width of each nearly equal to distance between them; interocular tuberculi large; basomedial fovea nearly
as deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; microreticulate,
with fine, moderately dense punctures and fine hairs. Labroclypeal suture straight. Labrum length 0.33 width; surface
with microreticulation and fine hairs; median emargination absent; median 0.33 upturned to form a small tooth (males).
Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of 3. Mentum width equal length, shining,
with small punctures; anterior margin arcuate. Submentum finely punctulate. Genae shining, swollen. Postgena finely

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Fig. 121. Geographical distribution of Ochthebius aztecus.

punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near anterior 0.33) 0.56 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior
angles. Lateral hyaline border origin near midlength of lateral depression, extended straight to posterior angles, very
narrow around posterior margin. Anterior margin of pronotum arcuate, without crenulations in front of each lateral
depression; anterior angles obtuse. Lateral depressions flat, microreticulate with small, sparse punctures and fine hairs;
margins moderately arcuate; pronotum slightly constricted behind lateral depressions. Lateral fossulae moderately
deeply impressed, with well developed microreticulation; inner margin abrupt, posterior extreme tapered into lateral
hyaline border. Pronotal disc moderately convex, punctures in interfoveal area moderately small, separated by one-three
times puncture diameter; with fine, sparse hairs; surface between punctures smooth and shiny. Median groove well
developed, microreticulate. Anterior foveae oval, deep, connected to median groove by microreticulate depression.

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Posterior foveae oval, oblique, without abrupt lateral margins; posteromedial areas connected to median groove by
microreticulate depression. Posterolateral angles with with distinct impressions. Prosternum slightly elevated in midline;
coxae contiguous. Metasternum with well developed median glabrous area. Elytra: Length 1.08 mm. maximum width
(near midlength) 0.72 mm. Disc flat, shiny, with six rows of punctures between suture ahd humeri. Sides convex,
declivity beginning near posterior 0.33; punctures round; intervals flat, width equal puncture width, with very fine
impressed lines; interstices between punctures 0.50 puncture length; each puncture with prominent seta. Explanate
margin weakly developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal
0.50 glabrous, apical 0.50 with moderately long hairs. Legs: Moderately long and slender; ratio of hind leg length to
abdominal length 2.0: 1.0. Protarsomeres 1-3 with suction setae (males). Genitalia: Male (Fig. 1 43D)( 1 5 examined).

Variation. - Some specimens are uniformly dark brown and lack metallic reflections.
Females lack protarsal suction setae and lack the upturned labral margin. A total of 52
specimens were studied (see appendix).

Natural History. - Specimens collected by Frank N. Young (see appendix) have the
following note: “In salt lagoon back of beach. ..some shade from black mangrove growing
around edges, water shallow, warm... beetles collected in sun-warmed portion cut-off by a bar...
criss-crossed with stilt (bird) trails.” Two specimens were found in the intestine of a flamingo
collected on Isabel Island. This record of avian predation is unique among the Hydraenidae and
indicates that at least one species is subject to selective pressure by filter-feeding birds.

Distribution. - (Fig. 180). Galapagos Islands.

22. Ochthebius sculptoides new species
(Figs. 1 19G,H,122A-F,123B,180)

Type-locality. - Santa Clara River, Santa Paula, Ventura County. California, U.S.A.

Type-specimens. - Holotype male and allotype with identical locality data are in CAS. They
were collected by F.E. Blaisdell, July 20, 1923. Data about paratypes (242) are presented in the
appendix.

Diagnosis. - Dull pronotum with confluent posterior foveae and convex lateral depressions,
and the male genitalia serve to distinguish adults of this species. Refer to the sections on
variation and remarks for further comments.

Description. — Form: Ovate, moderately convex (Figs. 119G,H). Size: Holotype 1.76 mm long, 0.80 mm wide.
Color: Dorsum dark brown, venter slightly darker; legs slightly lighter. Head: Length 0.32 mm; width 0.44 mm. Frons
with small, rather widely spaced punctures, surface moderately shining, with very fine hairs; interocular foveae deep and
large, width of each nearly 0.66 distance between them; interocular tuberculi moderately large; basomedial fovea nearly as
deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with extremely
shallowly impressed microreticulation, nearly obsolete, punctures similar to those on frons, though somewhat denser, with
fine hairs. Labroclypeal suture straight. Labrum length 0.33 width; surface somewhat rugulose, with fine, sparse hairs;
median emargination of moderate depth and width, depth 0.33 length of labrum, width 0.25 width of labrum, lobes
upturned. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 nearly 0.50 length of 3. Mentum wider than
long, moderately shining, with dense, small punctures. Submentum evenly, finely punctulate, punctures contiguous. Genae
shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near
anterior 0.33) 0.60 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae,
then tapered to anterior angles. Lateral hyaline border origin near midlength of lateral depression, extended straight to
posterior angles, very narrow around posterior margin. Anterior margin of pronotum very arcuate, without crenulations in
front of lateral fossulae and with shallow excavation in front of each lateral depression; anterior angles obtuse. Lateral
depressions convex, with microreticulation, punctation and small indistinct hairs; margins moderately arcuate, with small
tooth at base of lateral depression; pronotum moderately constricted behind lateral depressions. Lateral fossulae
moderately deeply impressed, with well developed microreticulation; inner margin abrupt, posterior extreme tapered into
tooth at lateral hyaline border. Pronotal disc moderately convex, punctures moderately small, separated by one-three times
puncture diameter; with fine, sparse hairs; surfaces between punctures flat and smooth, but only moderately reflective.
Median groove moderately deep, moderately wide at anterior and posterior, constricted in middle 0.50, not attaining
anterior and posterior margins; microreticulation and punctures resulting in rugulose appearance. Anterior foveae
moderately deep, confluent with median groove. Posterior foveae with abrupt lateral margins; posteromedial areas
confluent with median groove; surface sculpture as in median groove. Posterolateral angles with distinct impressions.

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Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum without median glabrous area.
Elytra: Length 1.16 mm; maximum width (near midlength) 0.80 mm. Disc flat, moderately dull, with six rows of
punctures between suture and humeri. Sides convex, declivity origin near posterior 0.33; most punctures somewhat
elongate; intervals flat, width twice puncture width; interstices between punctures 0.50 puncture length; each puncture
with seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two
segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and slender; ratio
of hind leg length to abdominal length 2. 0:1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Figs. 122A-F)(56
examined).

Variation. - This species is fairly uniform in external character states throughout its
extensive range. There is some variation in depth of the pronotal median groove, posterior
foveae, and the shallow depressions connecting the foveae to the posterior portion of the median
groove. However, in all specimens studied the median groove is clearly evident between the
posterior foveae. The male genitalia vary notably; I have illustrated the usual form (Fig. 122A)
and some extremes (Figs. 122B-F). Because of overlap of character states between certain
specimens of O. sculptus, O. sculptoides, and O. tubus , the male genitalia must be relied upon
for positive identification (for further comments refer to the section on variation of O.
sculptoides and O. tubus).

Natural History. - Most locality records indicate “creek” as the site; one record states
“river in gravel but much algaceous slime” (B. Malkin), and a large series (56 specimens) was
taken by the same collector at “Ziegler Hot Springs” in Madison County, Montana.

Distribution. - (Figs. 123B,180). Western North America from the U.S.A.-Canadian
border to central Mexico. Easternmost known locality in the U.S.A. is in central Wyoming.

Etymology. - sculptus plus Greek suffix oides (resembling). I refer to the close resemblance
to O. sculptus.

Remarks. - It is possible that O. sculptus and O. sculptoides are in reality a single species
with several genitalic forms; that of O. sculptus being the most extreme variant. Although these
two species are sympatric in California, I have not seen a composite series from a single
locality, which might be cited as evidence for conspecificity. However, the genitalic variants of
O. sculptoides are not morphologically intermediate between the form commonly seen in O.
sculptoides and that of O. sculptus. Therefore, if they are conspecific, one must accept a fairly
common spontaneous “morphological jump” to the extreme (0. sculptus) form. Additionally,
one would need to explain the distribution in southern California, where only O. sculptus has
been found. Sympatry of the two forms throughout much of California, plus lack of genitalic
intermediates in geographically intermediate areas and, especially, the fact that other species of
Western Hemisphere Ochthebius do not demonstrate genitalic morphological gaps of this
magnitude without extensive geographical separation (see O. lineatus , for example) are the
primary reasons for my decision that the material represents two species.

23. Ochthebius sculptus LeConte
(Figs. 1 1 9F, 1 20E, 1 23 A, 1 80)

Ochthebius sculptus LeConte, 1878:381 (lectotype female in MCZ, here designated; type-locality: Gilroy, California,

U.S.A.). - Horn, 1 890:24. - Leech and Chandler, 1 956:333.

The syntype-series in the LeConte collection at the MCZ consists of two specimens. The
lectotype has the following labels: Cala. d/ Type 3129/ O. sculptus Lee./ LECTOTYPE
Ochthebius sculptus LeConte by P.D. Perkins 1977. According to LeConte’s (1878) notes
accompanying the original description, this specimen was collected at Gilroy, California. The
second specimen is a male of another species {O. biincisus , new species); the following labels

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are attached to the pin: Ariz./ Type 2 3129/ sculptus 2. Judging from Horn’s (1890)
redescription, he was apparently studying a specimen of O. biincisus.

Diagnosis. - Convex lateral depressions, moderately deep postocular emarginations, and the
male genitalia serve to distinguish this species. Refer to the sections on variation of O.
sculptoides, O. tubus , and this species for further comment.

Description. — Form: Ovate, moderately convex (Fig. 1 19F). Size: Lectotype 1.72 mm long, 0.75 mm wide. Color:
Dorsum and venter dark brown, nearly black; legs brown. Head: Length 0.28 mm; width 0.45 mm. Frons with small,
rather widely spaced punctures, surface shining, with very fine hairs; interocular foveae deep and large, width of each
nearly 0.66 distance between them; interocular tuberculi moderately large; basomedial fovea nearly as deep as interocular
foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with extremely shallowly impressed
microreticulation, nearly obsolete, punctures similar to those on frons, though somewhat denser; with fine hairs.
Labroclypeal suture straight. Labrum length 0.33 width; surface somewhat rugulose, with fine, sparse hairs; median
emargination of moderate depth and width, depth 0.33 length of labrum, width 0.25 width of labrum. Maxillary palpus
with palpomere 3 moderately wide; palpomere 4 nearly 0.50 length of 3. Mentum width equal length, moderately shining,
with moderately dense, small punctures. Submentum evenly, finely punctulate, punctures contiguous. Genae shining,
swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.38 mm; maximum width (near anterior 0.33)
0.56 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered
to anterior angles. Lateral hyaline border origin near midlength of lateral depression, extended straight to posterior angles,
very narrow around posterior margin. Anterior margin of pronotum weakly arcuate, without crenulations in front of lateral
fossulae and with shallow excavation in front of each lateral depression; anterior angles obtuse. Lateral depressions convex,
with microreticulation, punctation and small hairs; margins moderately arcuate, with small tooth at base of lateral
depression; pronotum slightly constricted behind lateral depressions. Lateral fossulae moderately deeply impressed, with
well developed microreticulation; inner margin abrupt, posterior extreme tapered into tooth at lateral hyaline border.
Pronotal disc moderately convex, punctures moderately small, separated by one-three times puncture diameter; with fine,
sparse hairs; surfaces between punctures flat and smooth, very reflective. Median groove rather shallow, moderately wide
at anterior and posterior, constricted in middle 0.50, not extended to anterior and posterior margins; with microreticulation
and punctures, resulting in rugulose appearance. Anterior foveae moderately deep, confluent with median groove. Posterior
foveae with abrupt lateral margins; posteromedial areas confluent with median groove; surface sculpture as in median
groove. Posterolateral angles with distinct impressions. Prosternum with median carina ended at coxal cavities; coxae
contiguous. Metasternum without median glabrous area. Elytra: Length 1.16 mm; maximum width (near midlength)
0.75 mm. Disc flat, moderately dull, with six rows of punctures between suture and humeri. Sides convex, declivity
beginning near posterior 0.33; most punctures round; intervals flat, with impressed, fine lines, width slightly greater than
puncture width; interstices between punctures 0.50 puncture length; each puncture with seta. Explanate margin
moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50
glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg length to abdominal
length 2.0: 1.0. Protarsi without suction setae. Genitalia: Male (Fig. 120E)(37 examined).

Variation. - O. sculptus displays geographical variation in both form and sculpture, with a
south-north increase in sculpture depth and in values for the ratio of elytral length to pronotal
width. Therefore, specimens from Mexico appear somewhat smoother and broader than
specimens from northern California. Degree of separation of anterior pronotal foveae from the
posterior foveae varies independently of the former characters. In most specimens this
separation is quite distinct, but few specimens possess a very narrow channel connecting the two
foveae (on one or both sides of the pronotum). Externally, certain specimens of O. sculptus , O.
sculptoides , and O. tubus are indistinguishable, but the male genitalia are quite distinct and
must be studied for positive identification (further comments are presented under the sections
on variation and remarks O. sculptoides and O. tubus). I have examined 147 specimens (see
appendix).

Natural History. - Locality data indicate a lotic preference for O. sculptus , although a few
specimens were collected at margins of lakes.

Distribution. - (Figs. 123A,180). Coastal mountain ranges of California and southern
Oregon.

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Figs. 122A - F, Aedeagi of Ochthebius sculptoides. (A) holotype (inset: apex rotated slightly). (B) Weber County,
Arizona. (C) Aguascalientes, Mexico. (D) Cochise County, Arizona. (E) San Benito County, California. (F) Durango,
Mexico.

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24. Ochthebius tubus new species

(Figs. 3 A,B,D, 1 OA, 1 1 A, 1 1 2B, 1 24C,D, 1 35B, 1 48 A, 1 49 A, C, 1 52A, 1 80)

Type-locality. - Pool in canyon, elevation 3700 feet, La Suerte, Sierra San Pedro Martir,
Baja California Norte, Mexico.

Type-specimens. - Holotype male and allotype with same locality data are in CAS. They
were collected by R.K. Benjamin, June 4, 1963. Data about paratypes (282) are presented in
the appendix.

Diagnosis. - Within the biincisus Group, distinguishing characteristics include: dull,
microreticulate pronotal reliefs, confluent posterior foveolae, flat lateral depresssions, and male
genitalia. Refer to section on variation for further comments.

Description. — Form: Ovate, moderately convex (Fig. 1 12B). Size: Holotype 1.76 mm long, 0.76 mm wide. Color:
Dorsum dark brown, venter slightly darker; legs, palpi and elytral epipleura slightly lighter. Head: Length 0.34 mm; width
0.48 mm. Frons with moderately large, dense punctures in midline, surface shiny, with very fine hairs; interocular foveae
deep and large, width of each nearly 0.66 distance between them; interocular tuberculi moderately large; basomedial fovea
nearly as deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with
punctures separated by one-three times puncture diameter, with fine hairs. Labroclypeal suture straight. Labrum length
0.33 width; surface somewhat rugulose, with fine, dense hairs; median emargination of moderate depth and width, depth
0.33 length of labrum, width 0.25 width of labrum, lobes upturned. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4 nearly 0.66 length of 3. Mentum width equal length, moderately shining, with sparse, small punctures;
anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near anterior 0.33) 0.60 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior gles.
Lateral hyaline border beginning near midlength of lateral depression, extended straight to posterior angles, very narrow
around posterior margin. Anterior margin of pronotum shallowly bisinuate, without crenulations in front of lateral fossulae
and with very shallow excavation in front of each lateral depression; anterior angles obtuse. Lateral depressions flat, with
dual, irregular punctation and small hairs; margins moderately arcuate; pronotum very slightly constricted behind lateral
depresssions. Lateral fossulae moderately deeply impressed, with well developed microreticulation; inner margin abrupt,
posterior extreme tapered into lateral hyaline border. Pronotal disc moderately convex, punctures moderately small,
separated by one-three times puncture diameter; with fine, sparse hairs; surface between punctures smooth and shiny.
Median groove moderately deep, rather narrow, not extended to anterior and posterior margins; with microreticulation and
punctures. Anterior foveae rather shallow, connected to median groove by shallow depression with well developed
punctation. Posterior foveae with abrupt lateral margins; posteromedial areas confluent with median groove; surface
sculpture as in median groove. Posterolateral angles with distinct impressions. Prosternum with median carina ended at
coxal cavities; coxae contiguous. Metasternum without median glabrous area. Elytra: Length 1.12 mm; maximum width
(near midlength) 0.76 mm. Disc flat, moderately dull, with six rows of punctures between suture and humeri. Sides
convex, declivity beginning near posterior 0.33; most punctures somewhat elongate; intervals flat, width equal puncture
width; interstices between punctures 0.50 puncture length; each puncture with seta. Explanate margin moderately
developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous,
apical 0.50 with very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg length to abdominal length
2.0: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Figs. 124C,D)(77 examined); female (Fig. 10A).

Variation. - This species exhibits considerable variation in degree of development of the
median groove and posterior foveae. At one extreme, the median groove and posterior foveae
are quite distinct, with each fovea joined to the median groove by a shallow depression; at the
other extreme, the posterior foveae are broadly and deeply confluent and the posterior portion
of the median groove is absent. In the latter extreme, some specimens have the median groove
unconnected to the confluent posterior foveae, and therefore duplicate the form seen in certain
specimens of the borealis Subgroup (see discussion of variation under O. borealis , O. marinus
O. uniformis , and O. kaszabi). O. tubus , however, differs from the aforementioned species in
the shape of the labrum (deeply emarginate in both sexes) and shape of the anterior pronotal
margin (compare Figs. 106A,112B). O. tubus also exhibits noteworthy variation in size of the
acute process behind the lateral depression. At its greatest development this process is quite
distinctive (Fig. 1 12B), but some specimens lack the process entirely, while in others this area is

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Figs. 123A - B, Geographical distributions of Ochthebius species. (A) O. sculptus. (B) O. sculptoides (localities in squares
are those for which aedeagi are illustrated in Figs. 122A-F).

very slightly indented. In the latter character state, however, the indentation does not approach
the extent seen in such species as O. pacificus and O. arenicolus (Figs. 97A,B). O. tubus is most
closely similar to O. sculptus and O. sculptoides. Depth of the pronotal foveae and degree of
convexity of the lateral depressions are expressed maximally in some specimens of O. sculptus ,
but, as in other external characters, overlap between the three species is seen. The overlap of
this and other external characters necessitates referral to the male genitalia for unequivocal
species assignment (Figs. 120E,122A-F,124C,D).

Natural History. - Most commonly collected at the margins of streams. Altitude does not
seem to be a limiting factor. Perkins (1976) discusses some details of the microhabitat
preferences of O. tubus under the name O. interruptus.

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Distribution. - (Figs. 1 35B, 1 80). Western North America between the U.S.A.-Canadian
border and central Mexico. Most frequently collected in California, where only one of the many
records are from the Sierra Nevada Mountains, the remainder being from the coastal
mountains and adjacent areas.

Etymology. - Latin, tubus (pipe). Named in reference to the shape of the aedeagal apical
piece.

25. Ochthebius alpinopetrus new species
(Figs. 99B,1 12A,124B,180)

Type-locality. - Middle Casper Creek at Highway 20, ca. 2.5 mi. SE Natrona, Natrona
County, Wyoming, U.S.A.

Type-specimens. - The holotype male and allotype, which have identical locality data, are
deposited in CAS. Hugh B. Leech collected them August 20, 1965. Data about paratypes (14)
are presented in the appendix.

Diagnosis. - The male genitalia should be used to differentiate this species from O.
spanglerorum. Refer to the sections on variation of the two species for comparisons.

Description. — Form: Elongate oval, weakly convex (Fig. 112A). Size: Holotype 1.96 mm long, 0.80 mm wide.
Color: Head, pronotum and venter dark brown; elytra, legs and palpi brown. Head: Length 0.34 mm; width 0.46 mm.
Frons with moderately large, dense punctures in midline, surface shiny, with very fine hairs, lateral areas microreticulate
between punctures; interocular foveae deep and large, width of each nearly 0.66 distance between them; interocular
tuberculi moderately large; basomedial fovea nearly as deep as interocular foveae, smaller. Frontoclypeal suture evenly
arcuate. Clypeus length 0.50 width: microreticulate between somewhat dense, moderately large punctures; with fine hairs.
Labroclypeal suture straight. Labrum length 0.33 width; surface with fine punctures and fine, dense hairs; median
emargination rather shallow and narrow, depth 0.25 length of labrum, width 0.20 width of labrum, neither edge nor lobes
upturned. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 nearly 0.66 length of 3. Mentum width equal
length, moderately shining, with sparse, small punctures; anterior margin arcuate. Submentum evenly, finely
microreticulate. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.44 mm;
maximum width (near anterior 0.33) 0.62 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in
front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin near midlength of lateral depression,
extended straight to posterior angles, very narrow around posterior margin. Anterior margin of pronotum shallowly
bisinuate, without crenulations in front of lateral fossulae and with shallow excavation in front of each lateral depression;
anterior angles obtuse. Lateral depressions slightly convex, microreticulate with irregular punctation and small hairs;
margins moderately arcuate; pronotum moderately constricted behind lateral depressions. Lateral fossulae moderately
deeply impressed, with well developed microreticulation; inner margin abrupt, posterior extreme tapered into lateral
hyaline border. Pronotal disc moderately convex, interfoveal areas with moderately large punctures, separated by two-five
times puncture diameter; with fine, sparse hairs; surface between punctures smooth and shiny. Median groove well
developed in anterior and posterior, middle 0.50 constricted, reduced to a narrow, shallow sulcus; not extended to anterior
and posterior margins; microreticulate. Anterior foveae well developed, elongate ovals separated from median groove by
fovea width. Posterior foveae well developed, elongate ovals twice size of adjacent portion of median groove; separated
from median groove by width of fovea; microreticulate. Posterolateral angles with distinct impressions. Prosternum with
median carina ended at coxal cavities; coxae contiguous. Metasternum without median glabrous area. Elytra: Length
1.28 mm; maximum width (near midlength) 0.80 mm. Disc flat, moderately shiny, with six rows of punctures between
suture and humeri. Sides convex, declivity beginning near posterior 0.33; most punctures round; intervals flat, width equal
puncture width, with fine impressed lines; interstices between punctures 0.25 puncture length; each puncture with seta.
Explanate margin weakly developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth,
basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg length to
abdominal length 2.0:1. 0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 124B)(6 examined).

Variation. - Slight variation in the pronotal sculpture was seen in the 16 specimens studied,
and is discussed in relation to that of O. spanglerorum, in the section on that species.

Distribution. - (Figs. 99B,180). Rocky Mountains of Wyoming and Colorado.

Etymology. - Latin, alpinus (high mountains) plus petrus (rock). I refer to the geographical
distribution, the Rocky Mountains.

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Figs. 124A - D, Aedeagi of Ochthebius species. (A) O. spanglerorum , holotype. (B) O. alpinopetrus. holotype. (C) O.
tubus , specimen from Val Verde County, Texas. (D) O. tubus , holotype.

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26. Ochthebius spanglerorum Wood and Perkins
(Figs. 99B, 1 1 2C, 1 24A, 1 80)

Ochthebius spanglerorum Wood and Perkins, 1978:56 (holotype male in USNM; type-locality: Navajo Spring Creek,

Montezuma County, Colorado, U.S.A.).

Diagnosis. - Nearly parallel lateral hyaline borders, shallow postocular emarginations, and
short lateral depressions of the pronotum (Figs. 112A,C) are diagnostic features for O.
spanglerorum and O. alpinopetrus. Aedeagal differences must be used to reliably distinguish
males of these two species. Refer to the variation section for additional comparisons and
comments.

Description. — Form: Elongate oval, weakly convex (Fig. 112C). Size: Holotype 1.92 mm long, 0.80 mm wide.
Color: Head, pronotal disc and venter dark brown; pronotal lateral depressions, elytra, legs and palpi brown. Head: Length
0.30 mm; width 0.46 mm. Frons shallowly punctate in midline, shiny, very sparsely pubescent; lateral areas very faintly
microreticulate; interocular foveae deep and large, width of each nearly 0.66 distance between them; interocular tuberculi
moderately large; basomedial fovea nearly as deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate.
Clypeus length slightly greater than 0.50 width, microreticulate, sparsely pubescent. Labroclypeal suture straight. Labrum
length slightly less than 0.33 width; sparsely pubescent; median emargination small, depth 0.25 length of labrum, width
0.20 of labrum, neither edge nor lobes upturned. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 nearly
0.66 length of 3. Mentum width equal length, moderately shining, with sparse, small punctures; anterior margin arcuate.
Submentum evenly, finely microreticulate. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length
at midline 0.42 mm; maximum width (near anterior 0.33) 0.58 mm. Anterior hyaline border moderately wide in front of
disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin near
midlength of lateral depression, extended straight to posterior angles, very narrow around posterior margin. Anterior
margin of pronotum with shallow postocular emarginations; anterior angles obtuse. Lateral depressions convex, faintly
microreticulate and punctate, shiny; margins moderately arcuate; pronotum moderately constricted behind lateral
depressions. Lateral fossulae moderately deeply impressed, with well developed microreticulation; inner margin abrupt,
posterior extreme tapered into lateral hyaline border. Pronotal disc moderately convex, moderately punctate, surface
between punctures smooth and shiny. Median groove well developed in anterior and posterior, middle 0.50 constricted,
reduced to narrow, shallow sulcus; not extended to anterior and posterior margins; microreticulate. Anterior foveae well
developed, elongate ovals separated from median groove by fovea width. Posterior foveae well developed, elongate, ovals,
microreticulate. Anterior and posterior pair of pits for pronotal sensilla rather well devloped. Posterolateral angles with
distinct impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum pubescent,
without median glabrous area. Elytra: Length 1.20 mm; maximum width (near midlength) 0.80 mm. Disc flat, moderately
shiny, with six rows of punctures between suture and humeri. Sides convex, declivity origin near posterior 0.33; most
punctures round; intervals flat, width equal puncture width, with fine impressed lines; interstices between punctures 0.25
puncture length; each puncture with seta. Explanate margin slightly developed. Abdomen: Basal five sterna with
hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs:
Moderately long and slender; ratio of hind leg length to abdominal length 2. 0:1.0. Protarsomeres 1-3 with suction setae.
Genitalia: Male (Fig. 124A)(29 examined).

Variation. - O. spanglerorum adults exhibit considerable variation in degree of separation
of the anterior and posterior foveae of the pronotum, the foveae being distinctly separated on
some specimens and narrowly confluent on others. In addition, microreticulation of the
posterior foveae and median sulcus are contiguous on some specimens and non-contiguous on
others. Since O. alpinopetrus shows these pronotal variations also, and is indistinguishable from
O. spanglerorum on other external features, the male genitalia must be studied to distinguish
specimens of these two closely related species.

Distribution. - (Figs. 99B,180). General region of the Rocky Mountains in the states of
Colorado, New Mexico, North Dakota, Utah, and Wyoming, U.S.A.

27. Ochthebius aztecus Sharp
(Figs. 96F, 1 1 9B, 1 20A-D, 121,180)

Ochthebius aztecus Sharp, 1887:768 (lectotype male in BMNH, here designated; type-locality: Mexico City, Mexico). -

d’Orchymont, 1943:40.

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Ochthebius bruesi Darlington, 1928:3 (holotype male in MCZ; type-locality: Beowawe, Nevada, U.S.A.; new synonomy).

- d’Orchymont, 1943:40. - Leech, 1966:137.

Darlington’s type-specimen does not differ significantly from Sharp’s type-specimen. I have
illustrated the aedeagus of the lectotype of O. aztecus (Fig. 120A); the aedeagus of the
holotype of O. bruesi is most similar to that illustrated from a specimen collected in Death
Valley National Monument, California (Fig. 120D).

Diagnosis. - O. aztecus adults are readily distinguished by having the abdominal sternum 6
hydrofuge pubescent. Dorsally they are distinctive also because of the well separated, elongate
posterior pronotal foveae and the discrete median groove which is gradually tapered to a point
at the ends (Fig. 96F).

Description. — Form: Elongate, moderately convex (Fig. 119B). Size: Lectotype 1.84 mm long, 0.80 mm wide.
Color: Head, pronotum and venter dark brown; elytra, legs and palpi light brown. Head: Length 0.30 mm; width 0.48 mm.
Frons with moderately large, dense punctures in midline, surface shiny, with very fine hairs; interocular foveae deep and
large, width of each nearly 0.66 distance between them; interocular tuberculi moderately large; basomedial fovea nearly as
deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with moderately large
punctures, microreticulation and fine hairs. Labroclypeal suture straight. Labrum length 0.33 width; with fine, dense
hairs; median emargination absent, edge upturned slightly in midline. Maxillary palpus with palpomere 3 moderately
wide; palpomere 4 0.50 length of 3. Mentum width equal length, shining, with sparse, small punctures; anterior margin
arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate.
Thorax: Pronotum length at midline 0.46 mm; maximum width (near anterior 0.33) 0.62 mm. Anterior hyaline border
moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline
border origin near midlength of lateral depression, extended straight to posterior angle, very narrow around posterior
margin. Anterior margin of pronotum arcuate, without crenulations in front of lateral fossulae; shallow excavation in front
of each lateral depression; small tooth at the medial extreme of excavation; anterior angles acute. Lateral depressions
convex, densely punctate, microreticulate, moderately pubescent; margins moderately arcuate; pronotum moderately
constricted behind lateral depressions. Lateral fossulae deeply impressed, with well developed microreticulation; inner
margin abrupt, posterior extreme tapered into lateral hyaline border. Pronotal disc moderately convex, punctures small,
separated by one-three times puncture diameter; with fine, sparse hairs; surface between punctures smooth and shiny.
Median groove moderately deep, moderately wide, tapered at anterior and posterior; with microreticulation. Anterior
foveae elongate, narrow and moderately deep; separated from median groove by three times fovea width. Posterior foveae
very elongate, narrow and deep; parallel to median groove; separated from median groove by three times fovea width;
surface microreticulate. Posterolateral angles with distinct impressions. Prosternum with median carina ended at coxal
cavities; coxae contiguous. Metasternum without median glabrous area. Elytra: Length 1.20 mm; maximum width (near
midlength) 0.80 mm. Disc flat, moderately dull, with six rows of punctures between suture and humeri. Sides convex,
declivity beginning near posterior 0.33; most punctures round; intervals flat, width equal puncture width, with extremely
fine punctures and irregular lines; interstices between punctures 0.25 puncture length; each puncture with seta. Explanate
margin moderately developed. Abdomen: Basal six sterna with hydrofuge pubescence. Apical segment smooth, basal 0.50
glabrous, apical 0.50 with long hairs. Legs: Long and slender; ratio of hind leg length to abdominal length 2.0: 1.0.
Protarsomeres 1-3 with suction setae. Genitalia: Male (Figs. 120A-D)(38 examined).

Variation. - Adults display notable variation in dorsal and aedeagal characters. Specimens
from Mexico have more densely pubescent lateral pronotal depressions than have those from
other areas. Pronotal sculpture is deepest on specimens from North Dakota. Some specimens
from various localities have the head, prothorax and anterior margin plus humeri of the elytra
very dark brown, which contrasts with the testaceous color of the remainder of the elytra. This
contrast is especially pronounced in specimens from Oregon. The principal aedeagal variation
has been illustrated (Figs. 120A-D). A total of 524 specimens were examined (see appendix).

Natural History. - Specimens are frequently collected in thermal springs and adjacent
runoff areas, but the species is not restricted to those biotopes. Locality data also suggest an
affinity for alkaline conditions.

Distribution. - (Figs. 121,180). Western United States southward to Mexico City and
vicinity.

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28. Ochthebius biincisus new species
(Figs. 125D,126A,127B,180)

Type-locality. - Little Sur River, vicinity of Pacific Ocean, Monterey County, California,
U.S.A.

Type-specimens. - The holotype male and allotype with identical locality data are in
USNM. I collected these specimens, September 6, 1970. Data about paratypes (32) are
presented in the appendix.

Diagnosis. - Black color plus pronotal form with its deep postocular emarginations, deep,
well separated foveae and deep median groove (Fig. 125D) serve to characterize this species.

Description. — Form: Ovate, moderately convex (Fig. 125D). Size: Holotype 2.00 mm long, 0.92 mm wide. Color:
Dorsum and venter black; legs and palpi light brown. Head: Length 0.32 mm; width 0.48 mm. Frons with moderately large
punctures, separation one-three times puncture diameter, surface very shiny, with very sparse, fine hairs; interocular
foveae deep and large, width of each nearly 0.66 distance between them; interocular tuberculi moderately large;
basomedial fovea very small, not as deep as interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus length 0.50
width; with moderately large, distinct punctures, separation one-three times puncture diameter, with very sparse hairs in
lateral areas. Labroclypeal suture straight. Labrum length 0.33 width; surface with small punctures and dense hairs;
median emargination very small, with upturned margin which makes emargination not visible from dorsal view. Maxillary
palpus with palpomere 3 moderately wide; palpomere 4 nearly 0.66 length of 3. Mentum width equal length, moderately
shining, microreticulate, punctate, anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous.
Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.42 mm; maximum width (near
anterior 0.33) 0.64 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae,
then tapered to anterior angles. Lateral hyaline border origin near midlength of lateral depression, extended very slightly
arcuate to posterior angles, very narrow around posterior margin. Anterior margin of pronotum shallowly bisinuate,
without crenulations in front of lateral fossulae and with deep excavation in front of each lateral depression; anterior angles
acute. Lateral depressions slightly convex, with microreticulation, irregular punctation and small indistinct hairs; margins
moderately arcuate, with small tooth at base of lateral depression; pronotum moderately constricted behind lateral
depressions. Lateral fossulae deeply impressed, with well developed microreticulation; inner margin abrupt, posterior
extreme tapered into tooth at lateral hyaline border. Pronotal disc moderately convex, punctures moderately small,
separated by one-three times puncture diameter; with extremely fine, extremely sparse hairs; surfaces between punctures
flat, smooth, and very shiny. Median groove moderately deep, wide at anterior and posterior, constricted in middle 0.50,
not extended to anterior and posterior margins, microreticulate. Anterior foveae moderately deep, narrow and elongate.
Posterior foveae oval, with all margins ended equally abrupt; surface sculpture as in median groove. Posterolateral angles
with distinct impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum without
median glabrous area. Elytra: Length 1.36 mm; maximum width (near midlength) 0.92 mm. Disc flat, moderately shiny,
with six rows of punctures between suture and humeri. Sides convex, declivity origin near posterior 0.33; most punctures
somewhat elongate; intervals flat, width twice puncture width; interstices between punctures 0.50 puncture length; each
puncture with seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence.
Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and
slender; ratio of hind leg length to abdominal length 1.6: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male
(Fig. 1 26A)( 1 6 examined).

Variation. - The one specimen (male) from Oregon has the midlength constriction of the
median groove slightly less well developed than in most specimens from California. Many
specimens have testaceous or orange legs which contrast attractively with the deep black color
of the body.

Natural History. - The series of 15 specimens from which the holotype was selected were
collected at the margin of the Little Sur River, approximately 300 meters from where the river
enters the ocean. Salinity measurements were not taken, but it seems highly probable that the
water was brackish. The substratum consisted of rocks and sand. All other locality data suggest
freshwater habitats.

Distribution. - (Figs. 127B,180). Pacific coastal mountain ranges from southernmost
Oregon southward to Monterey County, California.

Etymology. - Latin bi (two) plus incisus (cut into). I refer to the deep postocular
emarginations of the pronotum.

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Figs. 125A - F, Ochthebius body outlines. (A) O. obscurus. (B) O. gruwelli. (C) O. mexcavatus. (D) O. biincisus. (E) O.
madrensis. (F) O. pauli.

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Figs. 126A - D, Aedeagi of Ochthebius species. (A) O. biincisus , holotype (inset: apex rotated slightly). (B) O. obscurus ,
lectotype. (C) O. gruwelli, holotype. (D) O. arizonicus, holotype (inset: apex rotated slightly).

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Figs. 127A - B, Geographical distributions of Ochthebius species. (A) O. madrensis • , O. mexcavatus ★ and O. pauli
A • (B) O. biincisus • , O. arizonicus ★ and O. gruwelli A •

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29. Ochthebius gruwelli new species
(Figs. 125B,126C,127B,180)

Type-locality. - 2.2 miles SE El Topo, Sierra Juarez, Baja California Norte, Mexico.

Type-specimens. - The holotype male is in USNM. It was collected, March 25, 1970 by
John A. Gruwell and me. We collected the allotype the following day, 20 miles N. of El Rodeo,
Baja California Norte. Data about paratypes (27) are presented in the appendix.

Diagnosis. - The black dorsum and shiny pronotum with its shallow, transversely confluent
foveae, nearly obliterated median groove, and deep postocular emarginations (Fig. 125B) serve
as diagnostic characteristics for O. gruwelli. Externally, adults of O. gruwelli are very similar
to those of O. arizonicus. The male genitalia of the two species are quite distinct, and, together
with the allopatric distribution, readily distinguish the two. Refer to the diagnosis of O.
arizonicus for further comparisons.

Description. — Form: Ovate, moderately convex (Fig. 125B). Size: Holotype 1.84 mm long, 0.84 mm wide. Color:
Dorsum and venter black; legs and palpi brown. Head: Length 0.34 mm; width 0.50 mm. Frons with moderately large
punctures, separation one-three times puncture diameter, surface shining with very sparse, fine hairs; interocular foveae
deep and large, width of each nearly 0.66 distance between them; interocular tuberculi moderately large; basomedial fovea
nearly as deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with
moderately large punctures in midline, separation one-three times puncture diameter; lateral areas with microreticulation
in addition to punctures. Labroclypeal suture straight. Labrum length 0.33 width; surface with small punctures and dense
hairs; median emargination of moderate depth and width, depth 0.33 length of labrum, width 0.25 width of labrum, sides
of emargination upturned slightly. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 nearly 0.50 length of
3. Mentum width equal length, moderately shining, with small punctures; anterior margin arcuate. Submentum evenly,
finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at
midline 0.42 mm; maximum width (near anterior 0.33) 0.62 mm. Anterior hyaline border moderately wide in front of disc,
slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin near midlength of
lateral depression, extended straight to posterior angles, very narrow around posterior margin. Anterior margin of
pronotum shallowly bisinuate, lacking crenulations in front of each lateral depression; anterior angles acute. Lateral
depressions slightly convex, with small punctures, microreticulation and small indistinct hairs; margins moderately
arcuate, with a small tooth at base of lateral depression; pronotum moderately constricted behind lateral depressions.
Lateral fossulae moderately deeply impressed, with well developed microreticulation; inner margin abrupt, posterior
extreme tapering into tooth at lateral hyaline border. Pronotal disc moderately convex, punctures moderately small,
separated by one-five times puncture diameter; with fine, very sparse hairs; surfaces between punctures flat, smooth, and
shiny. Median groove nearly obsolete in middle of disc, reduced to narrow, shallow channel, anterior and posterior
extremes more developed, microreticulate in addition to small punctures. Anterior foveae moderately deep, narrow and
elongate, connected to median groove by shallow depression. Posterior foveae elongate and narrow, connected to median
groove by shallow depression; surface sculpture as in median groove. Posterolateral angles with distinct impressions.
Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum without median glabrous area.
Elytra: Length 1.20 mm; maximum width (near midlength) 0.84 mm. Disc flat, moderately dull, with six rows of
punctures between suture and humeri. Sides convex, declivity origin near posterior 0.33. most punctures somewhat
elongate; intervals flat, width 1.5 puncture width, with fine impressed lines; interstices between punctures 0.50 puncture
length; each puncture with seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge
pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately
long and slender; ratio of hind leg length to abdominal length 2. 0:1.0. Protarsomeres 1-3 with suction setae. Genitalia:
Male (Fig. 126C)(8 exmained).

Variation. - Specimens from Baja California frequently have the pronotal sculpture more
deeply impressed than specimens from further north, but this difference is very slight. The
aedeagi of northernmost known males, from Los Angeles County, are virtually identical to
those of specimens from Baja California.

Natural History. - O. gruwelli has been collected at the margins of both streams and ponds.
Some details of this species’ microhabitat preferences are presented by Perkins (1976) under
the name O. lineatus.

Distribution. - (Figs. 127B,180). Coastal mountains of southern California and northern
Baja California.

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Etymology. - I take pleasure in dedicating this species to my good friend and fellow aquatic
Coleopterist, John A. Gruwell, who initiated my interest in water beetles.

30. Ochthebius arizonicus new species

(Figs. 126D,127B,180)

Type-locality. - 19 mi. N. Roosevelt, Sycamore Creek, Gila County, Arizona, U.S.A.

Type-specimens. - The holotype male and allotype with identical data are deposited in
USNM. Joe Schuh collected these specimens April 6, 1966. Data about paratypes (17) are
presented in the appendix.

Diagnosis. - Externally, adults are very similar to those of O. gruwelli. The latter species,
however, is from southern California and adjacent Baja California. The male genitalia of the
two species (Figs. 126C,D) are quite distinct. The aedeagus of O. gruwelli has the apical piece
strongly arcuate, with the thin margin wide, whereas the apical piece of O. arizonicus is not
arcuate and has the thin margin quite narrow. Additionally, the apex of the main-piece is
narrower and much more acute in O. arizonicus.

Description. — Form: Ovate, moderately convex (Fig. 125B). Size: Holotype 1.88 mm long, 0.84 mm wide. Color:
Dorsum and venter black; legs and palpi brown. Head: Length 0.34 mm; width 0.50 mm. Frons finely punctate; interocular
foveae moderately deep, width of each equal to distance between them; interocular tuberculi large; basomedial fovea
nearly as deep and as large as interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width, finely
punctate. Labroclypeal suture straight. Labrum length 0.33 width, finely punctate, finely pubescent; median emargination
very small, edge upturned very slightly. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 slightly greater
than 0.50 length of 3. Mentum width equal length, shining, finely punctate; anterior margin arcuate. Submentum evenly,
finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at
midline 0.44 mm; maximum width (near anterior 0.33) 0.62 mm. Anterior hyaline border moderately wide in front of disc,
slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin near midlength of
lateral depression, extended straight to posterior angles, very narrow around posterior margin. Anterior margin of
pronotum straight, postocular emarginations well developed, postocular processes absent. Lateral depressions flat, densely,
coarsely punctate, finely pubescent; margins moderately arcuate; pronotum moderately constricted behind lateral
depressions. Lateral fossulae moderately deeply impressed, microreticulate, moderately coarsely punctate; inner margin
moderately abrupt, posterior extreme tapered into lateral hyaline border. Pronotal disc moderately convex, finely, sparsely
punctate. Median groove absent. Anterior foveae small, shallow, joined by very shallow, transverse depression. Posterior
foveae moderately deep and large, joined by very shallow, transverse depression. Posterolateral angles with with distinct
impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum without median
glabrous area. Elytra: Length 1.20 mm; maximum width (near midlength) 0.84 mm. Disc moderately convex, moderately
dull, with six rows of punctures between suture and humeri. Declivity origin near posterior 0.33. Intervals flat, width equal
puncture width, with fine impressed lines. Interstices between punctures 0.50 puncture length. Each puncture with seta.
Explanate margin slightly developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments
smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg
length to abdominal length 1.9: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 126D)(8 examined).

Variation. - The series from which the holotype was selected exhibits considerable variation
in depth of the pronotal impressions. At one extreme the foveae are shallowly impressed and the
median groove is absent. At the other extreme the foveae are deeper and joined by a narrow,
longitudinal groove; shallow, transverse depressions joining the foveae of opposite sides are
deeper, and there is a very shallow median groove.

Distribution. - (Figs. 1 27B, 1 80). Eastern Arizona.

Etymology. - arizonicus, in reference to the geographical distribution.

31. Ochthebius madrensis new species

(Figs. 125E,127A,131B,180)

Type-locality. - Southwest Research Station, Portal, Cochise County, Arizona, U.S.A.

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Type-specimens. - The holotype male and allotype with identical locality data are in
USNM. These specimens were collected by W.E. Steiner May 14, 1976. Data about paratypes
(11) are presented in the appendix.

Diagnosis. - Black color, shiny pronotum with shallow postocular emarginations and
confluent foveae (Fig. 125E), and male genitalia are diagnostic for this species.

Description. — Form: Ovate, moderately convex (Fig. 125E). Size: Holotype 1.72 mm long, 0.80 mm wide. Color:
Dorsum and venter black; legs and palpi brown. Head: Length 0.34 mm; width 0.42 mm. Frons with moderately large
punctures, separation one-three times puncture diameter, surface moderately shining, with obvious hairs; interocular
foveae deep and large, width of each nearly 0.66 distance between them; interocular tuberculi moderately large;
basomedial fovea nearly as deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50
width; with moderately large punctures in midline, separation one-three times puncture diameter; lateral areas with
microreticulation in addition to punctures; with obvious hairs. Labroclypeal suture straight. Labrum length nearly 0.50
width; surface with small punctures and dense hairs; median emargination moderately deep and wide, depth 0.33 length of
labrum, width 0.25 width of labrum, sides of emargination slightly upturned. Maxillary palpus with palpomere 3
moderately wide; palpomere 4 0.50 length of 3. Mentum width equal length, moderately shining, with small punctures;
anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near anterior 0.33) 0.56 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border origin near midlength of lateral depression, extended straight to posterior angles, very narrow
around posterior margin. Anterior margin of pronotum shallowly bisinuate, without crenulations in front of lateral fossulae
and with excavation in front of each lateral depression; small tooth at median extreme of excavation slightly upturned;
anterior angles acute. Lateral depressions flat, with microreticulation, moderately sized punctures and distinct hairs;
margins moderately arcuate, with small tooth at base of lateral depression; pronotum moderately constricted behind lateral
depressions. Lateral fossulae moderately deeply impressed, with well developed microreticulation; inner margin abrupt,
posterior extreme tapered into tooth at lateral hyaline border. Pronotal disc moderately convex, punctures moderately
small, separated by one-three times puncture diameter; with fine, sparse hairs; surfaces between punctures flat, smooth
and shiny. Median groove reduced to very narrow and shallow groove not connected with confluent posterior foveae, but
connected with shallow depression united to anterior foveae. Anterior foveae narrow and elongate. Posterior foveae
elongate and narrow, connected by channel to anterior foveae; posterior extremes of posterior foveae united by well
developed depression with punctation. United anterior and posterior foveae in form of sinuate line. Posterolateral angles
with distinct impressions. Prosternum with median carina ended at coxal cavities, coxae contiguous. Metasternum without
median glabrous area. Elytra: Length 1.12 mm; maximum width (near midlength) 0.80 mm. Disc flat, moderately dull,
with six rows of punctures between suture and humeri. Sides convex, declivity origin near posterior 0.33; most punctures
somewhat elongate, intervals flat, width 1.5 puncture diameter; interstices between punctures 0.50 puncture length; each
puncture with seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence.
Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, long hairs. Legs: Moderately long and
slender; ratio of hind leg length to abdominal length 1.7: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male
(Fig. 131 B)(4 examined).

Variation. - Despite the distance separating the Arizona and Mexico populations
(Fig. 127A), the male genitalia and external characteristics of the two groups are virtually
identical.

Natural History. - My wife Maureen and I collected three specimens from the sandy
margins of a stream flowing through a pine forest meadow in the mountains west of Durango,
Mexico. One specimen from the Chiricahua mountains of Arizona was taken at an ultraviolet
light.

Distribution. - (Figs. 127A,180). Known from southeastern Arizona and one locality in
Durango, Mexico. Future collecting will probably reveal a general distribution throughout the
Sierra Madre Occidental mountains.

Etymology. - madrensis , in reference to distribution in the Sierra Madre Occidental
mountains.

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32. Ochthebius pauli new species
(Figs. 125F,127A, 1290,180)

Type-locality. - Nine miles SE El Tule, Oaxaca, Mexico.

Type-specimens. - The holotype male and one male paratype with same data are deposited
in USNM. Paul J. Spangler collected these specimens August 24, 1965.

Diagnosis. - Adults are similar to those of O. madrensis in most respects, including shallow
postocular emarginations, confluent posterior foveae, and black color. The elytra characteristic
of O. pauli , however, have the punctures large and striate-impressed, the width of the rows
being equal to or greater than the intervals, whereas in O. madrensis adults the serial punctures
are small, not as wide as the intervals, and not striate-impressed. Additionally, the lateral
depressions of the pronotum are more convex in O. pauli , and the aedeagus is different from
that of O. madrensis (Figs. 129D,131B).

Description. — Form: Ovate, moderately convex (Fig. 125F). Size: Holotype 1.68 mm long, 0.80 mm wide. Color:
Dorsum and venter black, legs and palpi dark brown. Head: Length 0.30 mm; width 0.42 mm. Frons moderately punctate,
shiny except in microreticulate areas near eyes; pubescence moderately developed; interocular foveae well developed, width
of each 0.66 distance between them; interocular tuberculi moderately large; basomedial fovea smaller than interocular
foveae. Frontoclypeal suture slightly angulate. Clypeus shiny, length slightly less than 0.50 width, punctures in midline
separated by two-three times puncture diameter; lateral areas more densely punctate, slightly microreticulate, moderately
pubescent. Labroclypeal suture straight. Labrum length nearly 0.50 width, microreticulate, pubescent; median
emargination well developed, depth 0.33 length of labrum, width 0.25 width of labrum; lobes formed by emargination at
angle to remainder of labrum. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of 3. Mentum
quadrate, finely punctate; anterior margin arcuate to rear. Submentum evenly, finely punctulate. Genae shiny, swollen.
Postgena finely punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near anterior 0.33) 0.56 mm.
Anterior hyaline border moderately wide in front of disc, twice this width in front of lateral fossulae, then tapered to
anterior angles. Lateral hyaline border origin near midlength of lateral depression, extended staight and slightly
convergent to posterior angles, very narrow around posterior margin. Anterior margin of pronotum straight except small
postocular emarginations; anterior angles acute. Lateral depressions slightly convex, moderately punctate and
microreticulate; margins slightly arcuate; pronotum moderately constricted behind lateral depressions. Lateral fossulae
moderately deeply impressed, microreticulate. Pronotal disc moderately convex, punctures small, separated by one-three
times puncture diameter, interstices shiny. Median groove narrow, united at posterior with confluent posterior foveae.
Anterior foveae narrow, elongate, microreticulate, joined to median groove by very shallow, non-microreticulate
depression. Posterior foveae narrow, elongate, microreticulate, united to median groove by microreticulate and punctate
depression. Posterior angles with distinct impressions. Prosternum with median carina ended at coxal cavities, coxae
contiguous. Metasternum without median glabrous area. Elytra: Length 1.04 mm; maximum width (near midlength)
0.80 mm. Disc slightly convex, with six rows of striate-impressed, relatively large punctures between suture and humeri.
Intervals rounded, width less than that of punctures. Each puncture with seta. Explanate margin weakly developed.
Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with
very fine, long hairs. Legs: Moderately long and slender. Protarsomeres 1-3 with suction setae. Genitalia: Male
(Fig. 129D)(2 examined).

Variation. - The posterior foveae of the single male paratype are not united to the median
groove as they are in the holotype. The aedeagus of the paratype, however, is identical to that of
the holotype.

Distribution. - (Figs. 127A,180). Presently known only from the type-locality near El Tule,
Oaxaca, Mexico.

Etymology. - It is a pleasure to dedicate this species to Paul J. Spangler, my friend, mentor
and colleague. He has collected the only known specimens of O. pauli, as well as the only
known material of several other hydraenid species.

33. Ochthebius mexcavatus new species
(Figs. 1 25C, 1 27 A, 1 28 A-F, 1 29E, 1 80)

Type-locality. - Madicolous habitat, El Diablo, ca. 100 miles W. Durango, Mexico.

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Type-specimens. - The holotype male and allotype with identical locality data are in
USNM. My wife Maureen and I collected these specimens, July 18, 1974. Data about
paratypes (135) are presented in the appendix.

Diagnosis. - Pronotal form, with very deep postocular emarginations and large, acute
processes behind the lateral depressions (Figs. 125C,128A) serve as diagnostic characteristics
for this very distinctive species.

Description. — Form: Ovate, moderately convex (Fig. 125C). Size: Holotype 1.68 mm long, 0.80 mm wide. Color:
Body uniformly dark brown, moderately reflective. Head: Length 0.32 mm; width 0.46 mm. Frons with moderately sized
punctures, separation one-three times puncture diameter, surface moderately shining, with obvious hairs; interocular
foveae deep and large, width of each nearly 0.66 distance between them; interocular tuberculi moderately large;
basomedial fovea very small. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with small punctures,
separation five times diameters; hairs quite prominent. Labroclypeal suture straight. Labrum length nearly 0.50 width;
surface with small punctures and dense hairs; median emargination deep and wide, depth nearly 0.50 length of labrum,
width 0.25 width of labrum, lobes markedly upturned. Maxillary palpus with palpomere 3 moderately wide; palpomere 4
0.50 length of 3. Mentum width equal length, moderately shining, with small punctures; anterior margin arcuate. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.42 mm. maximum width (near anterior 0.33) 0.60 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border origin near midlength of lateral depression, extended straight to posterior angles, very narrow
around posterior margin. Anterior margin of pronotum shallowly bisinuate, without crenulations in front of lateral fossulae
and with very deep excavation in front of each lateral depression; small tooth at median extreme of excavation slightly
upturned; anterior angles acute. Lateral depressions slightly convex, with moderate sized punctures, microreticulation, and
small indistinct hairs; margins excavated in posterior 0.50, with pronounced tooth at base of excavation; pronotum
moderately constricted behind lateral depressions. Lateral fossulae deeply impressed, with well developed
microreticulation; inner margin abrupt, posterior extreme tapered into tooth at lateral hyaline border. Pronotal disc
convex, punctures small, separation three-five times puncture diameter; hairs not apparent; surfaces between punctures
smooth and shiny; areas to each side of median groove slightly elevated and rounded. Median groove deep narrow channel
in middle of disc, anterior and posterior extremes obliterated by confluent anterior and posterior foveae. Anterior foveae
deep and confluent; lateral margin straight and nearly parallel to median groove. Posterior foveae somewhat triangular,
with well developed microreticulation; lateral extreme ended abruptly as straight line slightly oblique to median groove;
median extremes of foveae confluent. Posterolateral angles with distinct impressions. Prosternum with median carina
ended at coxal cavities; coxae contiguous. Metasternum without median glabrous area. Elytra: Length 1.08 mm;
maximum width (near midlength) 0.80 mm. Disc slightly convex, moderately dull, with six rows of punctures between
suture and humeri. Sides convex, declivity origin near posterior 0.33; most punctures round; intervals rounded and slightly
elevated, width equal to puncture diameter; interstices between punctures 0.25 puncture diameter; each puncture with
seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two
segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, long hairs. Legs: Moderately long and slender; ratio of
hind leg length to abdominal length 1.7: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 129E)(7
examined).

Variation. - The samples seen were quite homogeneous.

Natural History. - My wife Maureen and I collected 127 specimens from a hillside seepage
area in the mountains west of Durango, Mexico. The south-facing slope consisted of large rock
outcroppings, interspersed among grassy areas. The margins of each rock outcropping (where
the grass met the rock) were covered with a thin layer of flowing water, from which the beetles
were collected. Some specimens were taken by raising the grass and attached soil, to expose
more of the wet rock surface. The habitat did not appear to be madicolous in the strict sense,
that is, the slope of the hill was not as steep as usual in typical Central American madicolous
habitats. Nevertheless, one specimen of the strictly madicolous hydrophilid Oocyclus was found
on the seepage area.

Distribution. - (Figs. 127A,180). Sierra Madre Occidental mountains in the states of
Sinaloa and Durango, Mexico.

Etymology. - mexcavatus , referring to distribution and pronotal form.

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Figs. 128A - F, Ochthebius mexcavatus, 3. (A) pronotum (arrows indicate postocular emargination and process). (B)
labrum, dorsal view. (C) head ventral view. (D) labrum and mouthparts, anterior view. (E) prothoracic leg. (F) labral
emargination and sensilla, anterior view.

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371

Figs. 129A - E, Aedeagi of Ochthebius species. (A) O. mesoamericanus, holotype. (B) O. mesoamericanus, Durango,
Mexico. (C) O. mesoamericanus , San Luis Potosi, Mexico. (D) O. pauli, holotype. (E) O. mexcavatus , holotype.

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34. Ochthebius obscurus Sharp
(Figs. 10F,125A,126B,130,180)

Ochthebius obscurus Sharp, 1882:92 (lectotype male in BMNH, here designated; type-locality: Guanajuato, Mexico).

Diagnosis. - Black color, widely separated posterior foveae and absence of a median groove
serve to distinguish this member of the biincisus Group.

Description. — Form: Ovate, moderately convex (Fig. 125A). Color: Dorsum and venter black. Legs, palpi and
elytral epipleura brown. Head: Length 0.36 mm; width 0.52 mm. Frons shiny, finely moderately sparsely punctate,
punctures with very fine hairs; interocular foveae deep and large, width of each nearly 0.66 distance between them;
interocular tuberculi moderately large; basomedial fovea nearly as deep as interocular foveae, smaller. Frontoclypeal
suture evenly arcuate. Clypeus length 0.50 width; punctures separated by one-three times puncture diameter, with fine
hairs. Labroclypeal suture straight. Labrum length 0.50 width; anterior angles rounded; surface with small punctures and
fine, dense hairs; median emargination shallow, edge upturned slightly. Maxillary palpus with palpomere 3 moderately
wide; palpomere 4 nearly 0.66 length of 3. Mentum width equal length, moderately shiny with sparse, small punctures;
anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near anterior 0.33) 0.66 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border origin near midlength of lateral depression, extended straight to posterior angles, very narrow
around posterior margin. Anterior margin of pronotum straight, without crenulations in front of lateral fossulae and with
shallow excavation in front of each lateral depression; anterior angles acute. Lateral depressions flat, with moderate sized
punctures, microreticulation and small hairs; margins slightly arcuate; tooth at posterior extreme of lateral depression;
pronotum slightly constricted behind lateral depressions. Lateral fossulae moderately deeply impressed, with well
developed microreticulation; inner margin moderately abrupt, posterior extreme tapered into tooth at lateral hyaline
border. Pronotal disc moderately convex, punctures moderately small and sparse, separated by one-three times puncture
diameter; with fine, sparse hairs; surface between punctures smooth and very shiny. Median groove absent; a shallow,
transverse depression at anterior and posterior. Anterior and posterior foveae narrow grooves united in form of sinuate line,
anterior very shallow. Posterolateral angles with distinct impressions. Prosternum with median carina ended at coxal
cavities; coxae contiguous. Metasternum without median glabrous area. Elytra: Length 1.28 mm; maximum width (near
midlength) 0.88 mm; Disc slightly rounded, moderately shiny, with six rows of punctures between suture and humeri.
Sides convex, declivity origin near posterior 0.33; most punctures slightly elongate; intervals flat, width twice puncture
width; interstices between punctures 0.50 puncture length; each puncture with seta. Explanate margin moderately
developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous,
apical 0.50 with very fine short hairs. Legs: Moderately long and slender; ratio of hind leg length to abdominal length
1.7: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 126B)(2 examined); female (Fig. 10F)(3 examined).

Variation. - The two specimens from near Valle de Bravo, in the state of Mexico, differ
remarkably from the lectotype and the two specimens from Hidalgo (see appendix for locality
data). The former specimens are much smaller (1.72 vs 1.96 mm), more finely and sparsely
punctate on the pronotum and head, and have the pronotal foveae much more deeply
impressed. In addition, the postocular emarginations are slightly deeper. The aedeagus of the
single male from the state of Mexico, however, is virtually identical to that of the lectotype
(Fig. 126B), differing only in having the slender apex of the main-piece slightly shorter. I have
studied a total of only six specimens in addition to the lectotype (see appendix).

Natural History. - The two specimens from the state of Mexico were taken from a stream
containing an unusual abundance of leaf drift. This site is the type-locality of Spanglerina
ingens{Y\g. 197B). The two specimens from Hidalgo were at the sand-gravel margin of an
intermittent desert stream; Hydraena scintilla was also found at this locality.

Distribution. - (Figs. 130,180) Presently known from the states of Guanajuato, Hidalgo and
Mexico, Mexico.

Remarks. - The body outline illustration (Fig. 125 A) is that of the male specimen from the
state of Mexico.

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Fig. 1 30. Geographical distributions of Ochthebius mesoamericanus • and O. obscurus A •

35. Ochthebius mesoamericanus new species
(Figs. 1 1 9E, 1 29 A-C, 1 30, 1 80)

Type-locality. - Small pool at base of waterfall, 45 miles E. of Jalapa, Jalapa, Guatemala.

Type-specimens. - The holotype male and allotype with identical locality data are in
USNM. My wife Maureen and I collected these specimens, June 14, 1974. Data about
paratypes (85) are presented in the appendix.

Diagnosis. - Small size, dull pronotum with broadly confluent posterior foveae forming a
U-shaped depression, nearly obliterated median groove, and deeply emarginate labrum
(Fig. 1 19E) serve to characterize adults of this distinctive species.

Description. — Form: Ovate, moderately convex (Fig. 1 19E). Size: Holotype 1.60 mm long, 0.68 mm wide. Color:
Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.30 mm; width 0.40 mm. Frons finely, densely
punctate, microreticulation well developed, especially laterally; with very fine hairs; interocular foveae deep and large,
width of each nearly equal to distance between them; interocular tuberculi large; basomedial fovea nearly as deep and as
large as interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus length 0.60 width; finely densely punctate,
microreticulate and with fine hairs. Labroclypeal suture straight. Labrum length 0.33 width; surface with
microreticulation and fine dense hairs; median emargination large, U-shaped, depth 0.50 length of labrum, width 0.25
width of labrum; lobes upturned. Maxillary palpus with palpomere 3 moderately wide; ultimate segment 0.50 length of 3.
Mentum longer than wide, anterior margin deeply emarginate, surface shiny and with small punctures. Submentum
evenly, finely punctulate, punctures contiguous. Genae shining swollen. Postgena finely punctulate. Thorax: Pronotum
length at midline 0.34 mm; maximum width (near anterior 0.33) 0.50 mm. Anterior hyaline border moderately narrow in
front of disc, wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin near

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midlength of lateral depression, extended straight to posterior angles, very narrow around posterior margin. Anterior
margin of pronotum slightly bisinuate, without crenulations in front of each lateral fossula; small excavation in front of
each lateral depression; anterior angles acute. Lateral depressions flat, with well developed microreticulation and small
hairs; small tooth at posterior extreme; margins slightly arcuate; pronotum slightly constricted behind lateral
depressions. Lateral fossulae moderately deeply impressed, with well developed microreticulation; inner margin abrupt,
posterior extreme tapered into tooth at lateral hyaline border. Pronotal disc moderately convex, punctures in interfoveal
area moderately small, separated by one-two times puncture diameter; with fine, sparse hairs; surface between
punctures smooth and shiny. Anterior foveae broadly confluent in form of transverse depression with well developed
microreticulation. Posterior foveae broadly confluent in form of deep U-shaped depression with well developed
microreticulation. Median groove narrow and shallow, connected to confluent anterior and posterior foveae.
Posterolateral angles with distinct impressions. Prosternum with median carina ended at coxal cavities; coxae
contiguous. Metasternum without median glabrous area. Elytra: Length 0.96 mm; maximum width (near midlength)
0.68 mm. Disc flat, moderately shiny, with six rows of punctures between suture and humeri. Sides convex, declivity
beginning near posterior 0.33; punctures round; intervals flat, width equal puncture width, with fine impressed lines;
interstices between punctures 0.25 puncture length; each puncture with seta. Explanate margin weakly developed.
Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50
with very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg length to abdominal length 1.7: 1.0.
Protarsomeres 1-3 with suction setae. Genitalia: Male (Figs. 129A-C)(17 examined).

Variation. - The male genitalia (Figs. 129A-C) shows considerable variation in shape of the
apical piece. Externally adults are rather homogeneous throughout the range of this species,
except for color; specimens from northern Mexico are generally much lighter than those from
Guatemala.

Natural History. - Within lotic habitats, this species appears to have a rather wide
ecological tolerance, as specimens have been found in “small pool at base of waterfall”, “small,
rapid stream”, “tropical brook”, “stream in pine forest”, and “somewhat muddy stream”. I
collected a large series (50 specimens) from hard-packed gravel at the margin of a stream
flowing through a pine forest meadow in the mountains west of Durango, Mexico.

Distribution. - (Figs. 130,180). Known from the state of Sonora in northwest Mexico south
to Guatemala. Further collecting will probably reveal a widespread distribution throughout the
mountainous areas of Mexico and Central America.

Etymology. - mesoamericanus, in reference to the geographical distribution.

The benefossus Group

As commented upon in the discussion section of the genus, O. benefossus was formerly
placed in the subgenus Henicocerus, which is herein not considered of equal rank with
Asiobates and Ochthebius (sensu stricto). However, by the pronotal form (Figs. 96D,132B), O.
benefossus is clearly a member of the Henicocerus lineage, and should be included in any
consideration of the phylogeny of that group. In addition to the unusual pronotum, the
aedeagus is unique among Western Hemisphere Ochthebius in shape of the apical mobile piece,
which is subtriangular in cross-section (Fig. 131 A).

36. Ochthebius benefossus LeConte
(Figs. 10E,96D,99C,131A,132B)

Ochthebius benefossus LeConte, 1878:381 (holotype female in MCZ; type-locality: New Jersey, U.S.A.). - Horn,
1890:19.

The holotype is in poor condition, without the following structures: left elytron, all of left
hind leg except coxa, left middle tarsus, and left front tibia and tarsus.

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375

Diagnosis. - Pronotal form (Figs. 96D,132B) with flat lateral depressions, convex disc,
interrupted median groove, and narrow lateral hyaline borders within the posterior sinuations
serve as diagnostic characteristics for adults of this distinctive species.

Figs. 131 A - B, Aedeagi of Ochthebius species. (A) O. benefossus, specimen from Bennington County, Vermont. (B) O.
madrensis, holotype.

Description. — Form: Ovate, convex (Fig. 132B). Size: Flolotype 1.64 mm long, 0.80 mm wide. Color: Dorsum
black; venter dark brown; legs and palpi brown. Head: Length 0.32 mm; width 0.42 mm. Frons punctures separated by
puncture diameter in midline, closer laterally; with very fine hairs; interocular foveae deep and large, width of each nearly
0.66 distance between them; interocular tuberculi moderately large; basomedial fovea ill-defined. Frontoclypeal suture
evenly arcuate. Clypeus length 0.50 width; with punctation as frons, and fine hairs. Labroclypeal suture straight. Labrum
length 0.50 width; surface with small punctures and fine hairs; median emargination small, U-shaped; length 0.25 length
of labrum; width 0.20 labral width; lobes evenly rounded, not upturned. Maxillary palpus with palpomere 3 moderately
wide; palpomere 4 0.33 length of 3. Mentum width equal length, shining, with microreticulation and small punctures;
anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.42 mm; maximum width (near anterior 0.33) 0.52 mm. Anterior
hyaline border narrow. Lateral hyaline border origin at posterior extreme of lateral depression, very narrow, continuing
straight to posterior angles, extremely narrow around posterior margin. Anterior margin of pronotum bisinuate, with small
tooth in front of lateral fossulae; shallow, broad excavation in front of each lateral depression; anterior angles obtuse.
Lateral depressions flat, broad and relatively short, occupying 0.66 length of pronotum; margin irregular; internal area
very smooth and shiny; margins arcuate; pronotum moderately constricted behind lateral depressions. Lateral fossulae
deeply impressed, smooth; inner margin abrupt, posterior extreme tapered into lateral hyaline border. Pronotal disc very
convex, punctures in interfoveal area deeply impressed, moderately large, separated by puncture diameter or less; surface

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between punctures smooth and shiny. Median groove very broad anteriorly, tapered posteriorly, posterior extreme
separated from transverse depression, latter joined to posterior foveae. Posterior foveae very deeply impressed, oblique
ovals. Anterior foveae deeply impressed, circular, joined to median groove by depression. All depressions with
microreticulation and irregular punctation. Posterolateral angles with distinct impressions. Prosternum with shallow
transverse depression along entire anterior margin; median carina ended at coxal cavities; coxae contiguous.
Metasternum without median glabrous area. Elytra: Length 1 .00 mm; maximum width (near midlength) 0.80 mm. Disc
convex, shiny, with six rows of punctures between suture and humeri. Sides convex, declivity origin slightly past
midlength; punctures round; intervals flat, width equal puncture width; interstices between punctures 0.25 puncture
diameter; each puncture with very small seta. Explanate margin well developed, extended entire length of elytron.
Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50
with very fine, short hairs. Legs: Somewhat short and stout; ratio of hind leg length to abdominal length 1.3: 1.0.
Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 131 A)(2 examined); female (Fig. 10E).

Variation. - Specimens studied (39, see appendix) are quite homogeneous. Males are
differentiated from females by shape of labrum, which in the former has the emargination
smaller and its edge deflexed slightly.

Natural History. - Locality data give no indication of habitat preferences other than the
citation, “in wet Hypnum moss”.

Distribution. - (Fig. 99C). Northeastern North America from Quebec south to Virginia and
west to Indiana.

Remarks. - I have seen one specimen supposedly form Dunedin, Florida (W.S. Blatchley,
collector). This locality is far south of the general distribution and I believe that the label data
is incorrect.

The Subgenus Ochthebius (Asiobates)

As is described in the key to the subgenera, Ochthebius ( Asiobates ) is distinguished from the
nominate subgenus by pronotal and aedeagal differences.

The discretus Group

Members of this lineage are characterized by small to medium size (ca. 1.60-2.20 mm long)
and aedeagal form, which has the terminal mobile piece with a process ( mexicanus is an
exception) and the main-piece (in dorsal view) widest at its distal end, hence terminated
abruptly (Figs. 141 A-D). Additionally, the parameres are positioned in the same plane, side by
side.

Externally this group is quite diverse, morphological variation involving convexity,
sculpture, body shape, and loss of pronotal foveae.

The group has both temperate and tropical elements (Figs. 186-188); the five species of the
reticulocostus Subgroup found in Mexico live at relatively high elevations, perhaps reflecting
the temperate preferences of the group as a whole.

The morphological gap separating species of the reticulocostus Subgroup is rather
pronounced, suggesting that other species await discovery.

The discretus Subgroup

Members of this subgroup are characterized by well developed anterior and posterior

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pronotal foveae.

Four of the five included species are found in western North America (Fig. 186), one
{discretus) being widely distributed and commonly collected, the other three ( mimicus ,
hibernus and orbus) being very rare. The fifth species (putnamensis) is known only from
Indiana.

37. Ochthebius discretus LeConte
(Figs. 96E, 1 33D, 1 34A,B, 1 35 A, 1 86)

Ochthebius discretus LeConte, 1878:379 (lectotype male in MCZ, here designated; type-locality: San Diego, California,
U.S.A.). - Horn, 1890:21. - Fall, 1901:213. - Brown, 1931:1 17. - Brown, 1933:45. - Leech and Chandler, 1956:333. -
Hatch, 1965:19. - Perkins, 1976:316.

Ochthebius insulanus Brown, 1931:117 (holotype male in CNC; type-locality: Victoria, Vancouver Island, British
Columbia, Canada; new synonomy).

The type-series in the LeConte collection at the MCZ consists of five specimens, two of
which are O. rectus LeConte. The first two specimens are females. The third specimen, a male,
is lectotype. The male genitalia, in a microvial attached to the pin, are of the variant illustrated
from Baja California (Fig. 134A). The holotype of O. insulanus has the aedeagus of the form
illustrated (Fig. 134A) from Vancouver Island, British Columbia.

Diagnosis. - Adults of this widespread, common species with black integument can be
confused with the rare O. mimicus and O. orbus. O. mimicus adults are brown, more convex,
with lateral depressions shaped differently, and with posterior pronotal angles produced as

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Figs. 133 A - F, Ochthebius body outlines. (A) O. puncticollis. (B) O. orbus. (C) O. leechi. (D) O. discretus. (E) O.
mimicus. (F) O. putnamensis.

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379

Figs. 134A - C, Aedeagi of Ochthebius species. (A) O. discretus, aedeagal apex variation. (B) O. discretus , Sonoma
County, California. (C) O. hibernus, holotype.

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points instead of angulate. O. orbus adults are brown, more convex, with lateral pronotal
depressions less concave at rear and less markedly punctate (Figs. 96E,132C,133B,D). The
male genitalia of the three species also differ (Figs. 134A-C,141B).

Description. — Form: Ovate, weakly convex (Fig. 133D). Size: Lectotype 1.80 mm long, 0.84 mm wide. Color:
Dorsum and venter black; legs, palpi and antennae brown. Head: Length 0.32 mm; width 0.48 mm. Frons moderately
coarsely to moderately densely punctate, microreticulate laterally, finely pubescent; interocular foveae deep and large,
width of each nearly 0.66 distance between them; interocular tuberculi large, basomedial fovea nearly as deep and as large
as interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; sculpture as lateral areas of frons.
Labroclypeal suture straight. Labrum length 0.33 width, microreticulate, densely pubescent; median emargination present,
forming bilobed anterior. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of 3. Mentum
width equal length, shining, finely, moderately densely punctate; anterior margin arcuate. Submentum evenly, finely
punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline
0.44 mm; maximum width (near anterior 0.33) 0.64 mm. Anterior hyaline border moderately wide in front of disc, slightly
wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin at anterior angles, extended
very narrowly along lateral depressions, wide at excavation, very narrow around posterior margin. Anterior margin of
pronotum very slightly produced in middle 0.25, with small excavation in front of each lateral depression; anterior angles
obtuse. Lateral depressions flat, slightly inflated, broad, coarsely densely punctate, finely pubescent; margins moderately
arcuate, excavate at rear, small tooth lateral to excavation; pronotum markedly constricted behind lateral depressions.
Lateral fossulae deeply impressed, with well developed microreticulation; inner margin abrupt, posterior extreme tapered
into lateral hyaline border. Pronotal disc moderately convex, coarsely densely punctate, punctures separated by thin walls
to twice puncture diameter; with fine, sparse hairs; surface between punctures smooth and shiny. Median groove deep and
wide, very slightly constricted in middle 0.33. Anterior foveae deep and large, microreticulate, width equal to distance
between fovea and median groove. Posterior foveae deep and large, microreticulate. Posterolateral angles with distinct
impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median
glabrous area. Elytra: Length 1.20 mm; maximum width (near midlength) 0.84 mm. Disc slightly convex, with depression
in midregion, moderately shiny, with six rows of punctures between suture and humeri. Sides convex, declivity origin near
posterior 0.33; punctures round, intervals rounded, very slightly elevated, width equal puncture width, with fine impressed
lines; interstices between punctures 0.25 puncture length; each puncture with seta. Explanate margin slightly developed.
Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with
very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg length to abdominal length 1.6: 1.0.
Protarsomeres 1-3 with suction setae. Genitalia: Male (Figs. 134A,B)(133 examined).

Variation. - Specimens studied ranged from 1.68 mm to 2.20 mm in length. Some
individuals have the elytra more distinctly striate than others. Pronotal punctation varies
slightly in density and coarseness. Variation in the aedeagus primarily involves the relative sizes
of the middle and basal lobes of the apical piece; I have illustrated the principal variants
(Figs. 134A,B); no external variations correlating with these variants were noted. I examined
922 specimens (see appendix).

Natural History. - Many habitat descriptors (see appendix) mention “stream” or “river”,
less frequently “lake” or “pool”. Other, more unusual, descriptors include: “margin of Typha
pool”, “pool in dry stream bed”, “roadside marsh”, “bog”, “Hot Creek (it was cold)”, “seepage
trickle over gravelly soil”, and “clear water pools in gravel and stones of otherwise dry and
shaded creek bed”. There is no indication of halophilic or thermophilic tendencies in O.
discretus.

Distribution. - (Figs. 135A,186). Western North America from Aklavik, Northwest
Territories south to Baja California and east to Colorado. Very common in California, but not
yet found in the Death Valley region.

Remarks. - The large number of specimens available has permitted a detailing of genitalic
variation, thereby allowing closely related O. orbus to be discriminated as a distinct species,
and not a variant of O. discretus.

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38. Ochthebius hibernus new species
(Figs. 132C,134C,186)

Type-locality. - Oregon, U.S.A.

Type-specimens. - The holotype male is deposited in USNM. The collector is unknown. One
paratype male from Reindeer Depot, Mackenzie Delta, Northwest Territories, is deposited in
CNC.

Diagnosis. - Small size, brown color, convex form, pronotum with smooth, finely punctate
reliefs, rather wide lateral hyaline borders along the lateral depressions, and male genitalia are
the salient features of adults of O. hibernus. Adults are similar to those of O. mimicus and O.
orbus , but differ in pronotal form (Figs. 132C,133B,E), especially the short lateral depressions.

Figs. 135A - C, Geographical distributions of Ochthebius species. (A) O. discretus. (B) O. tubus. (C) O. puncticollis • ,
O. martini ★ and O. leechi A .

Description. — Form: Ovate, convex (Fig. 132C). Size: Holotype 1.52 mm long, 0.74 mm wide. Color: Brown, head
and pronotum darker than remainder. Head: Length 0.30 mm; width 0.46 mm. Frons sparsely finely punctate; interocular
foveae deep and large, width of each 0.66 distance between them; interocular tuberculi moderately large; basomedial fovea
smaller and shallower than interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width, finely
sparsely punctate. Labroclypeal suture straight. Labrum length 0.33 width, finely sparsely punctate. Labroclypeal suture
straight. Labrum length 0.33 width, finely punctate, finely sparsely pubescent; median emargination slightly developed,
edge slightly upturned. Maxillary palpomere 3 moderately wide; palpomere 4 0.50 length of 3. Mentum width equal
length, shining, sparsely finely pnctate, anterior margin arcuate. Submentum finely punctulate. Genae shining, swollen.
Postgena finely punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near anterior 0.33) 0.66 mm.
Anterior hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior
angles. Lateral hyaline border origin at anterior angles, rather wide along lateral depressions, wide in region of
excavations, very narrow around posterior margin. Anterior margin of pronotum straight, postocular processes very small,
postocular emarginations absent. Lateral depressions impunctate and inflated medially; finely punctate laterally; length of
lateral depressions very slightly more than 0.50 that of pronotum; latter markedly constricted behind lateral depressions.
Lateral fossulae deeply impressed, withou apparent microreticulation; inner margin abrupt, posterior extreme tapered into

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lateral hyaline border. Pronotal disc very convex, punctures in convex interfoveal areas fine and sparse; surface between
punctures smooth and shiny. Median groove narrow, moderately deep. Anterior foveae deep, moderately large,
subtriangular; width slightly less than distance between them and median groove. Posterior foveae deep, elongate.
Posterolateral angles with distinct impressions. Prosternum with median carina ended at coxal cavities; coxae
contiguous. Metasternum with large median glabrous area. Elytra: Length 1.00 mm; maximum width (near midlength)
0.74 mm. Disc convex, shining, with six rows of punctures between suture and humeri. Sides very convex. Declivity
origin near posterior 0.33. Intervals rounded, not elevated, width slightly greater than puncture width; interstices
between punctures equal puncture diameter; each puncture with extremely fine, short seta. Explanate margin weakly
developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous,
apical 0.50 with very fine, short hairs. Legs: Moderately long and stout; ratio of hind leg length to abdominal length
1.7: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 134C)(2 examined); female unknown.

Variation. - The one male paratype is much larger than the holotype (1.76 mm long and
0.88 mm wide) and darker, the color differences resulting from tenerality of the holotype.
External and genitalic characters agree very well with those of the holotype, however.

Natural History. - The paratype from Reindeer Depot, Northwest Territories represents
the northernmost known locality of a hydraenid beetle in the Western Hemisphere. This
distribution indicates that O. hibernus is one of the species better adapted to cold climates.

Distribution. - (Fig. 186). Known from one male specimen supposedly collected in Oregon
(site unspecified) and one male from Reindeer Depot, Northwest Territories.

Etymology. - Latin, hibernus (of winter). Named in reference to the cold climate of the
region this species inhabits.

39. Ochthebius orbus new species
(Figs. 133B,139B,141B,186)

Type-locality. - Redwood Creek at Highway 1, Marin County California, U.S.A.

Type-specimens. - The holotype male is deposited in USNM. I collected this specimen
October 24, 1971. The allotype and one female paratype (USNM) are from Portland,
Multnomah County, Oregon; Hubbard and Schwarz collectors.

Diagnosis. - Adults are most similar to those of O. discretus and O. mimicus , differing from
the former in color (brown instead of black), and in the shape of the lateral pronotal
depressions. Adults of O. orbus differ from those of O. mimicus in larger size and lack of the
produced posterior angles of the pronotum. In addition, male genitalia of the three species
differ (Figs. 134A-C,141B). Refer to the diagnosis of O. hibernus for additional comments.

Description. — Form: Ovate, convex (Fig. 133B). Size: Holotype 1.96 mm long, 0.96 mm wide. Color: Dorsum and
venter dark red-brown; legs, palpi and antennae testaceous. Head: Length 0.36 mm; width 0.50 mm. Frons sparsely, finely
punctate; interocular foveae deep and large, width of each equal to distance between them; interocular tuberculi large,
basomedial fovea smaller and shallower than interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus length 0.50
width, shiny, finely sparsely punctate, finely microreticulate. Labroclypeal suture straight. Labrum length 0.33 width,
finely microreticulate, finely pubescent; median emargination slightly developed. Maxillary palpus with palpomere 3
moderately wide; palpomere 4 0.50 length of 3. Mentum width equal length, shining, sparsely, moderately finely punctate,
anterior margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.50 mm; maximum width (near anterior 0.33) 0.76 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border origin at anterior angles, extended very narrowly along lateral depressions, wide in region of
excavation, very narrow around posterior margin. Anterior margin of pronotum straight, very small excavation in front of
each lateral depression; anterior angles obtuse. Lateral depressions slightly inflated, broad, shiny, coarsely sparsely
punctate, very sparsely pubescent; margins moderately arcuate, very deeply excavate at posterior, with small tooth lateral
to excavation; pronotum markedly constricted behind lateral depressions. Lateral fossulae deeply impressed, shiny, without
microreticulation; inner margin abrupt, posterior extreme tapered into lateral hyaline border. Pronotal disc markedly
convex, punctures in interfoveal area moderately large, separated by 0.5- 1.0 times puncture diameter; apparently
non-pubescent; surface between punctures smooth and shiny. Median groove moderately deep and wide, slightly wider in
posterior 0.25, microreticulate. Anterior foveae deep and large; width equal to distance between them from median groove.

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383

Posterior foveae large and deep, microreticulate. Posterolateral angles with distinct impressions. Prosternum with
median carina ended at coxal cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra: Length
1.28 mm; maximum width (near midlength) 0.96 mm. Disc convex, with depression in midregion, moderately shiny,
with six rows of round punctures between suture and humeri. Sides very convex, declivity origin near midlength;
intervals rounded, not elevated, width equal puncture width, with fine impressed lines; interstices between punctures
0.25 puncture length; each puncture with seta. Explanate margin slightly developed. Abdomen: Basal five sterna with
hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs:
Moderately short and stout; ratio of hind leg length to abdominal length 1.6: 1.0. Protarsomeres 1-3 with suction setae.
Genitalia: Male (Fig. 1 4 1 B)(2 examined).

Distribution. - (Figs. 1 39B, 1 86). Known only from Marin County, California and Portland,
Oregon.

Etymology. - Latin, orbus (bereft of parents). I refer to the apparently very rare nature of
this species.

40. Ochthebius mimicus Brown
(Figs. 133E,138A,139B,186)

Ochthebius mimicus Brown, 1933:45 (holotype female in CNC; type-locality: Summerland, British Columbia, Canada). -

Hatch, 1965:19.

Diagnosis. - Orange-brown color, convex form and pronotal features of broad, shiny lateral
depressions and produced posterior angles (Fig. 133E) serve to distinguish O. mimicus adults
from those of its close relatives.

Description. — Form: Broadly ovate, convex (Fig. 133E). Size: Holotype 1.80 mm long, 0.84 mm wide. Color:
Dorsum orange-brown, venter darker; legs and palpi testaceous. Head: Length 0.34 mm; width 0.50 mm. Frons slightly
elevated, finely punctate; interocular foveae microreticulate, deep and large, width of each 0.66 distance between them;
interocular tuberculi large; basomedial fovea nearly as deep and as large as interocular foveae. Frontoclypeal suture evenly
arcuate. Clypeus length 0.50 width; microreticulate at sides, finely pubescent. Labroclypeal suture straight. Labrum
length 0.33 width, microreticulate, finely pubescent; median emargination large, edge upturned slightly. Maxillary palpus
with palpomere 3 moderately wide; palpomere 4 short, 0.33 length of 3. Mentum width equal length, shining, finely
punctate; anterior margin arcuate. Submentum finely punctulate. Genae shining, swollen. Postgena finely punctulate.
Thorax: Pronotum length at midline 0.42 mm; maximum width (near anterior 0.33) 0.74 mm. Anterior hyaline border
moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline
border origin at anterior angles, narrow along lateral depressions, wide along posterior 0.50, very narrow around posterior
margin. Anterior margin of pronotum straight, with deep postocular emarginations and prominent postocular processes.
Lateral depressions wide, short, shiny, with few moderately coarse punctures; pronotum markedly constricted behind
lateral depressions. Lateral fossulae deeply impressed, very finely microreticulate; inner margin abrupt. Pronotal disc
convex, punctures in interfoveal area moderately large, separated by puncture diameter, or less; surface between punctures
smooth and shiny. Median groove narrow, moderately deep. Posterior foveae large, deep, oval, oblique, without apparent
microreticulation. Anterior foveae not as apparent as posterior, limits somewhat obscured by punctation. Posterolateral
angles with distinct impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum
with large median glabrous area. Elytra: Length 1.12 mm; maximum width (near midlength) 0.84 mm. Disc very convex,
moderately shiny, with six rows of punctures between suture and humeri. Sides convex, declivity origin near midlength.
Intervals rounded, not elevated, width twice puncture diameter. Interstices between punctures equal puncture diameter;
each puncture with seta. Explanate margin moderately developed. Abdomen : Basal five sterna with hydrofuge pubescence.
Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and
slender; ratio of hind leg length to abdominal length 1.7: 1.0. Protarsomeres without suction seta. Genitalia: Male
(Fig. 138A)(2 examined).

Variation. - No notable, non-sexual variation was seen in the 15 specimens studied (see
appendix). Females lack the protarsal suction setae of males; the labrum is very similar in the
sexes.

Natural History. - No specific habitat data, other than the citation, “Little Sand Creek”, is
present in the locality records.

Distribution. - (Figs. 139B,186). Southern British Columbia, Washington, and northern
Oregon.

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Figs. 136A - F, Ochthebius body outlines. (A) O. angularidus. (B) O. similis. (C) O. martini. (D) O. cribricollis. (E) O.
apache. (F) O. brevipennis.

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385

41. Ochthebius putnamensis Blatchley
(Figs. 1 33F, 1 86)

Ochthebius putnamensis Blatchley, 1910:253 (unique holotype female in PU; type-locality: Putnam County, Indiana,

U.S.A.).

Diagnosis. - Small size, very convex form and absence of postocular emarginations serve to
distinguish adults of this species from others of the discretus Subgroup.

Description. — Form: Broadly ovate, very convex (Fig. 133F). Size: Holotye 1.44 mm long, 0.80 mm wide. Color:
Dark brown, legs and palpi slightly lighter. Head: Length 0.34 mm; width 0.48 mm. Frons slightly elevated, finely
punctate; interocular foveae microreticulate, deep and large, width of each nearly 0.66 distance between them; interocular
tuberculi large; basomedial fovea ill-defined. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width, finely
punctate, finely pubescent. Labroclypeal suture straight. Labrum large, length nearly 0.50 width, microreticulate, finely
pubescent; median emargination well developed, edge not upturned. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4 short, 0.33 length of 3. Mentum width equal length, shining, finely punctate, finely pubescent, anterior
margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely
punctulate. Thorax: Pronotum length at midline 0.40 mm; maximum width (near midlength) 0.70 mm. Anterior hyaline
border narrow in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline
border origin at anterior angles, very narrow along lateral depressions, wide along posterior sides, very narrow around
posterior margin. Anterior margin of pronotum slightly arcuate in midline, with short, rather broad postocular processes,
without postocular emarginations. Lateral depressions flat, broad, posterior angles acute processes. Pronotum markedly
constricted behind lateral depressions. Lateral fossulae deeply impressed, finely microreticulate, inner margin abrupt.
Pronotal disc very convex, punctures coarse and dense along median groove, decreased in density laterally; finely, very
sparsely pubescent; surface between punctures smooth and shiny. Median groove microreticulate, moderately deep, widest
at posterior, anterior with indistinctly defined margins, punctures dense. Posterior foveae deep, large, oblong, finely
microreticulate. Anterior foveae deep, moderately large. Posterolateral angles with distinct impressions. Prosternum with
median carina ended at coxal cavities, coxae contiguous. Metasternum with large median glabrous area. Elytra: Length
0.98 mm; maximum width (near midlength) 0.80 mm. Disc very convex, moderately dull, with six rows of punctures
between suture and humeri. Sides convex, declivity beginning near posterior 0.33. Intervals rounded, very slightly elevated,
width 0.50 puncture diameter, with fine impressed lines. Interstices between punctures 0.25 puncture diameter. Each
puncture with seta. Explanate margin slightly developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical
two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately short and stout; ratio
of hind leg length to abdominal length 1.5: 1.0. Protarsomeres without suction setae. Genitalia: Male unknown.

Natural History. - Blatchley (1910) reports that the holotype was “sifted from debris at
side of hillside spring”.

Distribution. - (Fig. 186) Known only from the type-locality, Putnam County, Indiana.

The similis Subgroup

Adults of this subgroup are characterized by pronotal sculpture, which lacks anterior foveae,
this region being flat and moderately to finely punctate.

The one included species, O. similis , is known from Guatemala, Mexico and Arizona.

42. Ochthebius similis Sharp
(Figs. 136B,138B,142A,187A)

Ochthebius similis Sharp, 1 882:92 (holotype female in BMN H; type-locality: Guatemala City, Guatemala).

Ochthebius wickhami Fall, 1901:213 (holotype female in MCZ; type-locality: Winslow, Arizona, U.S.A.; new synonomy).

Fall’s type-specimen does not differ significantly from Sharp’s type-specimen. Refer to the
section on variation for further comments.

Diagnosis. - Lack of anterior pronotal foveae and distinctive body form (Fig. 136B) serve as
diagnostic characteristics for O. similis adults.

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Fig. 137. Geographical distribution of Ochthebius cribricollis.

Description. — Form: Ovate, slightly depressed (Fig. 136B). Size: Holotype 2.05 mm long, 0.93 mm wide. Color:
Brown tending toward testaceous, head darker. Head: Length 0.38 mm; width 0.52 mm. Frons finely, sparsely punctate;
interocular foveae deep and large, width of each equal to distance between them; interocular tuberculi large, basomedial
fovea nearly as deep and as large as interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width;
with microreticulation and fine hairs. Labroclypeal suture straight. Labrum length 0.33 width; surface microreticulate,
finely pubescent; median emargination weakly developed. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4 0.50 length of 3. Mentum width equal length, shining, finely, sparsely punctate; anterior margin arcuate.
Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax:
Pronotum length at midline 0.50 mm; maximum width (near anterior 0.33) 0.74 mm. Anterior hyaline border moderately
wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border
origin at anterior angles, extended very narrowly along lateral depressions, wide in region of excavation, very narrow
around posterior margin. Anterior margin of pronotum straight, with small excavation in front of each lateral depression;
anterior angles obtuse. Lateral depressions slightly inflated, broad, finely sparsely punctate; margins arcuate, posterior
extreme excavate, with small tooth lateral to excavation; pronotum constricted behind lateral depressions. Lateral fossulae
deeply impressed, slightly microreticulate; inner margin abrupt, posterior extreme tapered into lateral hyaline border.
Pronotal disc moderately flat, finely, sparsely punctate, punctures separated by one-three times puncture diameter; with
fine, very sparse hairs; surface between punctures smooth and shiny. Median groove narrow, moderately deep channel,
very slightly constricted in middle. Anterior foveae absent. Posterior foveae large, deeply impressed. Posterolateral angles
with shallow impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with
large median glabrous area. Elytra: Length 1.32 mm; maximum width (near midlength) 0.92 mm. Disc slightly convex,
with a shallow depression in midregion, moderately shiny, with six rows of round punctures between suture and humeri.
Sides convex, declivity origin near posterior 0.33; intervals rounded, width equal puncture width, surface smooth;
interstices between punctures 0.25 puncture length; each puncture with seta. Explanate margin slightly developed.
Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with

Western Hemisphere Hydraenidae 387

Figs. 138A - E, Aedeagi of Ochthebius species. (A) O. mimicus , British Columbia, Canada (inset: apex rotated slightly).
(B) O. similis, Coconino County, Arizona. (C) O. cribricollis , Renville County, North Dakota. (D) O. cribricollis, Napa
County, California. (E) O. brevipennis, holotype.

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very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg length to abdominal length 2.0: 1.0.
Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 138B)(6 examined).

Variation. - The holotype and the two Mexican specimens, one male each from the states of
Hidalgo and Veracruz (see appendix), are darker and have the pronotal punctation and
posterior foveae slightly more impressed than specimens from Arizona. Aedeagi from all areas,
however, are virtually identical. Males are easily distinguished from females by their unusually
large pads of protarsal suction setae.

Natural History. - Other than the locality record, “Salt Creek” (Coconino County,
Arizona), no indications of habitat are given. Judging from the Arizona records, this species
appears to be restricted to streams of arid regions. The holotype from Guatemala City (5,000
ft.) and the Vera Cruz specimen, however, suggest a less restricted ecological tolerance. The
single male from Pachuca, Hidalgo, Mexico was in a series with 25 specimens of G.fossatus.

Distribution. - (Figs. 142A,187A). Known from Guatemala City (holotype), central
Mexico (two males), and central Arizona (nine specimens, including Fall’s type-specimen) (see
appendix).

The cribricollis Subgroup

Adults of this subgroup, which have historically been placed in the subgenus
Homalochthebius, are characterized by absence of both anterior and posterior pronotal foveae.

One of the two presently included species, O. cribricollis , ranges across North America in a
rather narrow band near the Canada-U.S.A. border, and southward in the Pacific Coast states
to southern California. The other species, O. brevipennis , is found from southern British
Columbia southward to northern California.

43. Ochthebius cribricollis LeConte
(Figs. 136D,137,138C,D,187A)

Ochthebius cribricollis LeConte, 1850:217 (lectotype male in MCZ, here designated; type-locality: Eagle Harbor,

Michigan, U.S.A.). - LeConte, 1852:361. - LeConte, 1878:378. - Horn, 1890:22. - Leech and Chandler, 1956:333. -

Hatch, 1965:19.

Diagnosis. - Absence of pronotal foveae easily distinguishes O. cribricollis adults from all
other Western Hemisphere Ochthebius , except O. brevipennis . Adults of much rarer O.
brevipennis differ in the possession of a shallow, transverse depression at the base of the median
groove, shorter elytra, and aedeagal form (Figs. 136D,F,138C-E).

Description. — Form: Ovate, somewhat depressed (Fig. 136D). Size: Lectotype 2.00 mm long, 0.92 mm wide.
Color: Lateral depressions of pronotum, legs, palpi and antennae testaceous, remainder dark brown. Head: Length
0.40 mm; width 0.54 mm. Frons moderately coarsely, moderately densely punctate, microreticulate, weakly pubescent;
interocular foveae moderately deep and moderately large, width of each nearly 0.50 distance between them; interocular
tuberculi large, basomedial fovea nearly as deep and as large as interocular foveae. Frontoclypeal suture evenly arcuate.
Clypeus length 0.50 width; finely, sparsely punctate, markedly microreticulate, finely pubescent. Labroclypeal suture
straight. Labrum length slightly greater than 0.33 width; microreticulate, sparsely pubescent; extremely slightly
emarginate, entire anterior border extremely slightly upturned. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4 0.50 length of 3. Mentum width equal length, shining, finely sparsely punctate. Submentum evenly, finely
punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline
0.44 mm; maximum width (near anterior 0.33) 0.74 mm. Anterior hyaline border moderately wide in front of disc, slightly
wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin near anterior angles,
extended extremely narrowly along lateral depressions, moderately wide at excavations, very narrow around posterior
margin. Anterior margin of pronotum straight, without crenulations in front of lateral fossulae and without excavation in
front of each lateral depression; anterior angles obtuse. Lateral depressions flat, broad, smooth and shiny, sparsely.

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389

moderately finely punctate, pubescence not apparent; margins moderately arcuate, moderately excavate at posterior,
small tooth lateral to excavations; pronotum slightly constricted behind lateral depressions. Lateral fossulae shallowly
impressed, with weakly developed microreticulation; inner margin abrupt, posterior extreme ended before lateral hyaline
border. Pronotal disc slightly convex, shiny, moderately finely, moderately densely punctate, punctures separated by
0.5- 1.0 times puncture diameter, non-pubescent and non-microreticulate. Median groove shallow, extremely narrow.
Anterior foveae absent. Posterior foveae absent, this region very slightly depressed. Posterolateral angles without
impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median
glabrous area. Elytra: Length 1.28 mm; maximum width (near midlength) 0.92 mm. Disc flat, moderately dull, with six
rows of punctures between suture and humeri. Sides convex, declivity beginning near posterior 0.33; punctures round,
intervals flat, width twice puncture width, with dense fine impressed lines; interstices between punctures 0.25 puncture
length; each puncture with seta. Explanate margin weakly developed. Abdomen: Basal five sterna with hydrofuge
pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately
long and slender; ratio of hind leg length to abdominal length 2.0: 1.0. Protarsomeres 1-3 with suction setae. Genitalia:
Male (Figs. 138C,D)(17 examined).

Variation. - The aedeagal apex varies slightly; I have illustrated the maximum variation
noted, using a specimen from Napa County, California (Fig. 138D) and a specimen from
Sherwood, Renville County, North Dakota (Fig. 138C). I have examined 151 specimens (see
appendix).

Natural History. - It appears that this species has its greatest reproductive potential in pond
environments. This assertion is suggested by prevalence of such locality descriptors as “sandy
pool near Osoyoos Lake”, “pond meadow”, “small pond”, “flood water”, “mud bank along
lake” and other such indications of lentic habitats.

Distribution. - (Figs. 137,187A). Generally distributed in the Pacific Coast region of North
America from Santa Barbara, California to southern British Columbia, and trans-continental
as a rather narrow band near the U.S.A.-Canadian border. Easternmost known locality is
Wakefield, Quebec, Canada.

Remarks. - The lectotype aedeagus is of the form I have illustrated (Fig. 138C) using a
specimen from Sherwood, Renville County, North Dakota.

44. Ochthebius brevipennis new species
(Figs. 136F,138E,139A,187A)

Type-locality. - Under rocks by lake, Tierra del Mar, Tillamook County, Oregon, U.S.A.

Type-specimens. - The holotype male and allotype with identical locality data are deposited
in USNM. They were collected in 1938 (collector unknown). Data about paratypes (31) are
presented in the appendix.

Diagnosis. - Lack of anterior and posterior pronotal foveae distinguish specimens of O.
brevipennis from all Western Hemisphere Ochthebius , except O. cribricollis . O. brevipennis
specimens differ from the latter by a shallow, transverse depression at the base of the median
groove, shorter elytra, and form of male genitalia (Figs. 136D,F,138C-E).

Description. — Form: Ovate, moderately convex with head slightly deflexed (Fig. 136F). Size: Holotype 1.80 mm
long, 0.88 mm wide. Color: Dorsum black except testaceous elytral apices; venter dark brown; legs, palpi and antennae
testaceous. Head: Length 0.38 mm; width 0.52 mm. Frons moderately densely punctate laterally, markedly
microreticulate medially, moderately pubescent; interocular foveae shallow, moderately large, width of each nearly 0.66
distance between them; interocular tuberculi large, basomedial foveae nearly as deep and as large as interocular foveae.
Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; markedly, finely microreticulate, moderately pubescent.
Labroclypeal suture straight. Labrum length 0.33 width; microreticulate, densely pubescent; median emargination absent,
entire anterior margin very slightly upturned. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50
length of 3. Mentum width equal length, dull, densely, moderately finely punctate, anterior margin arcuate. Submentum
evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum
length at midline 0.55 mm; maximum width (near anterior 0.33) 0.74 mm. Anterior hyaline border moderately wide in
front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin near

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Figs. 139A - C, Geographical distributions. (A) Ochthebius brevipennis. (B) O. mimicus • and O. orbus A - (C)
Neochthebius vandykei.

anterior angles, extended extremely narrowly along lateral depressions, moderately wide at excavations, very narrow
around posterior margin. Anterior margin of pronotum straight, without crenulations in front of lateral fossulae and
without excavation in front of each lateral depression; anterior angles obtuse. Lateral depressions flat, deflexed,
moderately finely, densely punctate, moderately pubescent; margins moderately arcuate, moderately excavate at
posterior, small tooth lateral to excavation; pronotum slightly constricted behind lateral depressions. Lateral fossulae
moderately deeply impressed, shallowly microreticulate; inner margin abrupt, posterior extreme tapered into lateral
hyaline border. Pronotal disc moderately convex, densely moderately coarsely punctate, moderately pubescent; surface
between punctures smooth and shiny. Median groove shallow, extremely narrow. Anterior foveae absent, this region
densely punctate and slightly depressed. Posterior foveae broadly confluent in form of transverse punctate and
microreticulate depression. Posterolateral angles with shallow impressions. Prosternum with median carina ended at
coxal cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra: Length 1.16 mm; maximum
width (near midlength) 0.88 mm. Disc convex, shiny, with six rows of irregularly shaped punctures between suture and
humeri. Sides convex, declivity origin near midlength; intervals flat, width equal puncture width, with fine impressed
lines; interstices between punctures 0.25 puncture length; each puncture with seta. Explanate margin moderately

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391

developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous,
apical 0.50 with very fine short hairs. Legs: All legs moderately long and stout; ratio of hind leg length to abdominal
length 1.8: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 138E)(6 examined).

Natural History. - The locality data indicate that this species, like its close phylogenetic
relative, O. cribricollis , is primarily a pond species. Habitat descriptors include: “marshy
pond”, “small pond”, “flood water”, “mud bank along lake”, and “under rocks by lake”.

Distribution. - (Figs. 139A,187A). From Mendocino County, California northward to
southern British Columbia. Most widespread in Oregon.

Etymology. - Latin, brevis (short) plus pennis (wing). I refer to the elytra, which are
relatively short when compared to those of O. cribricollis , the most closely related species.

The reticulocostus Subgroup

This subgroup is characterized by the densely, coarsely punctate region generally occupied
by the anterior foveae. The latter are either absent or greatly obscured by the punctation.

One of the five included species, O. apache , is known from Mexico and the adjacent areas
of southern Arizona, New Mexico and Texas. The four other species are known only from
Mexico (Fig. 188).

45. Ochthebius apache new species
(Figs. 136E,141D,142A,187B)

Type-locality. - Carr Canyon, 7100 feet, Huachuca Mountains, Cochise County, Arizona,
U.S.A.

Type-specimens. - The holotype male and allotype with identical locality data are in
USNM. They were collected by Alan R. Gillogly, May 3, 1972. Data about paratypes (43) are
presented in the appendix.

Diagnosis. - Lack of pronotal postocular emarginations is sufficient to distinguish O. apache
adults from those of other species of O. ( Asiobates ) which also lack anterior pronotal foveae
(Fig. 136E).

Description. — Form: Ovate, moderately convex (Fig. 136E). Size: Holotype 2.00 mm long, 0.92 mm wide. Color:
Dorsum and venter black; legs and palpi dark brown. Head: Length 0.38 mm; width 0.54 mm. Frons with dense punctures,
some confluent, microreticulation well developed, with very fine hairs; interocular foveae deep and large, width of each
nearly 0.66 distance between them; interocular tuberculi large; basomedial fovea less deep and smaller than interocular
foveae. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; with well developed microreticulation and fine
hairs. Labroclypeal suture straight. Labrum length 0.33 width; surface with microreticulation and dense fine hairs;
anterior margin deeply emarginate, medially. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 slightly
less than 0.50 length of 3. Mentum width equal length, shining, with microreticulation and small punctures; anterior
margin arcuate. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely
punctulate. Thorax: Pronotum length at midline 0.48 mm; maximum width (near anterior 0.33) 0.76 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border origin near posterior extreme of lateral depression, extended slightly arcuate to posterior angles,
very narrow around posterior margin. Anterior margin of pronotum slightly sinuate, with very slightly produced sinuation
in midline and in front of each lateral fossula; anterior angles obtuse. Lateral depressions flat, broad, with large, rather
widely spaced punctures; very sparsely pubescent; margins moderately arcuate, posterior extreme excavated; pronotum
markedly constricted behind lateral depressions. Lateral fossulae deeply impressed, with well developed microreticulation;
inner margin abrupt, posterior extreme tapered into lateral hyaline border. Pronotal disc moderately convex, with large,
deep, dense, very regularly spaced punctures over entire surface, punctures separated by puncture diameter or less, but not
confluent; with fine sparse hairs; surface between punctures smooth and shiny. Median groove deeply impressed, enlarged
anteriorly and posteriorly as broad ovals with well developed microreticulation; anterior portion twice as large as posterior;
median 0.33 shallow, narrow furrow joined to both depressions. Anterior foveae absent, this area with very discrete

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Figs. 140A - C, Ochthebius body outlines. (A) O. reticulocostus. (B) O. browni. (C) O. mexicanus.

punctures. Posterior foveae large and very deep with punctures and microreticulation. Posterolateral angles with distinct
impressions. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median
glabrous area. Elytra: Length 1.28 mm; maximum width (near midlength) 0.92 mm. Disc flat, with broad, shallow
depression in middle, moderately shiny, with six rows of punctures between suture and humeri; first three rows from
suture slightly disordered in anterior 0.33. Sides convex, declivity origin near posterior 0.33; punctures round; intervals
rounded, slightly elevated, width equal puncture width, with some surface irregularities; interstices between punctures
0.25 puncture length; each puncture with seta. Explanate margin slightly developed. Abdomen: Basal five sterna with
hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs:
Moderately long and slender; ratio of hind leg length to abdominal length 1.7: 1.0. Protarsomeres 1-3 with suction setae.
Genitalia: Male (Fig. 141D)(20 examined).

Variation. - No significant differences were detected in the specimens studied.

Natural History. - Apparently restricted to streams of arid and semi-arid habitats. The one
specimen (male) from 29 mi.SW of Zacatecas, Mexico, was taken from the sand and gravel at
the margin of a desert stream; O. sculptoides was also collected at this locality. A series of
hydraenids collected by Frank N. Young at Rustler’s Park, Cochise County, Arizona,
contained adults of this species, and of Hydraena bituberculata, H. arizonica, and H. circulata.

Distribution. - (Figs. 142A,187B). Presently known to inhabit the mountains of
southeastern Arizona, the Rio Grande River drainage in New Mexico and Texas, and the state
of Zacatecas, Mexico.

Etymology. - A noun in apposition, apache , referring to the Apache Amerindians of the
southwestern United States, and to the hatchet, or “tomahawk” shape of the pronotal lateral
depressions.

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393

46. Ochthebius browni new species
(Figs. 140B,143C,187B)

Type-locality. - Vicinity of San Antonio, between Toluca and Temascaltepec, Mexico,
Mexico.

Type-specimens. - The holotype male and allotype are in USNM; one paratype female in
PDP; all with identical locality data. These three specimens were collected by Harley P. Brown,
October 1 1, 1966.

Diagnosis. - This species is similar to O. apicalis in that adults of both have the pronotum
densely punctate in the region normally occupied by the anterior foveae. O. browni differs in
being larger, less robust and lacking the distinctive fusiform shape of O. apicalis. Male
genitalia of the two species differ remarkably (Figs. 143A-C).

Description. — Form: Ovate, moderately convex (Fig. HOB). Size: Holotype 1.84 mm long, 0.92 mm wide. Color:
Dorsum and venter dark red-brown; legs and palpi orange-brown. Head: Length 0.36 mm; width 0.52 mm. Frons
prominently microreticulate over entire surface; punctures dense, but somewhat obscured by microreticulation; very finely
pubescent; interocular foveae deep and large, width of each equal to distance between them; interocular tuberculi large;
basomedial foveae nearly as deep as interocular foveae, smaller. Frontoclypeal suture evenly arcuate. Clypeus length 0.50
width; markedly microreticulate. Labroclypeal suture straight. Labrum length 0.33 width; microreticulate, finely
pubescent; median emargination well developed, edge upturned. Maxillary palpus with palpomere 3 moderately wide;
palpomere 4 slightly less than 0.50 length of penultimate. Mentum width equal length, shining, with small punctures;
anterior margin straight. Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.46 mm; maximum width (near anterior 0.20) 0.70 mm. Anterior
hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles.
Lateral hyaline border origin at anterior angles, extended extremely narrowly along lateral depressions, broad in region of
posterior excavation, very narrow around posterior margin. Anterior margin of pronotum straight, without crenulations in
front of lateral fossulae, with excavation in front of each lateral depression; anterior angles obtuse. Lateral depressions very
slightly inflated, broad, with large punctures and internal microreticulation; margins moderately arcuate; posterior
extremes excavate with very small tooth; pronotum moderately constricted behind lateral depressions. Lateral fossulae
moderately deeply impressed, with well developed microreticulation; inner margin abrupt, posterior extreme tapered into
lateral hyaline border. Pronotal disc moderately convex, punctures in interfoveal area moderately large, dense, irregularly
sized, separated by thin walls in anterior, some in posterior separated by puncture diameter; with fine, sparse hairs; surface
between punctures smooth and shiny. Median groove deeply impressed, narrow channel with well developed
microreticulation; anterior and posterior 0.33 very slightly wider than median 0.33. Anterior foveae absent, this region
with dense deep punctures. Posterior foveae large, deep, and microreticulate. Posterolateral angles with distinct
impressions. Prosternum with median carina ending at coxal cavities; coxae contiguous. Metasternum with large median
glabrous area. Elytra: Length 1 .28 mm; maximum width (near midlength) 0.92 mm. Disc with broad depression in
midregion, moderately shiny, with six rows of punctures between suture and humeri. Sides convex, declivity beginning near
posterior 0.33; punctures round; intervals rounded, slightly elevated, width equal puncture width, with surface
irregularities; interstices between punctures 0.25 puncture length; each puncture with seta. Explanate margin slightly
developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous,
apical 0.50 with very fine, short hairs. Legs: All legs moderately long and slender; ratio of hind leg length to abdominal
length 1.8: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 143C)(1 examined).

Variation. - Too few specimens are available to assess variation other than sexual: females
lack both protarsal suction setae and upturned edge of the labrum.

Distribution. - (Fig. 187B). Known only from the type-locality in the state of Mexico,
Mexico.

Etymology. - I acknowledge with pleasure the contributions made to this study by the
collecting efforts of Harley P. Brown, by naming this species after him.

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47. Ochthebius mexicanus new species
(Figs. 140C,141C,142B,187B)

Type-locality. - Temescaltepec, Mexico, Mexico.

Type-specimen. - The holotype male (unique) is deposited in BMNH. This specimen was
collected by H.E. Hinton and R.L. Usinger (no date).

Diagnosis. - The combination of large size, 2.28 x 1.04 mm, broad form (Fig. 140C), and
costate elytral intervals serve as diagnostic characteristics for this distinctive species. Pronotal
punctures are deeply impressed and moderately coarse, interstices elevated and microreticulate
but not markedly so. Its body form and sculpture presents a much different facies than that of
O. browni, the closest relative.

Description. — Form: Ovate, elytra rather markedly convex (Fig. 140C). Size: Holotype 2.28 mm long, 1.04 mm
wide. Color: Brown. Head: Length 0.44 mm; width 0.60 mm. Frons deeply, densely, moderately coarsely punctate;
interstices microreticulate; interocular foveae deep and large, width of each equal to distance between them; interocular
tuberculi large, shining; basomedial fovea nearly as large and as deep as interocular foveae. Frontoclypeal suture angulate,
deeply impressed. Clypeus length 0.50 width, sculptured as frons, pubescent laterally. Labrum length slightly less than
0.50 width, microreticulate, anterior margin rounded except for small median emargination. Maxillary palpus with
palpomere 3 relatively narrow; palpomere 4 0.50 length of 3. Mentum width equal length, coarsely, deeply punctate;
anterior margin arcuate to rear. Submentum microreticulate. Genae shining, swollen. Postgena finely punctulate. Thorax:
Pronotum length at midline 0.56 mm; maximum width (near midlength) 0.98 mm. Anterior hyaline border moderately
wide in front of disc, wider in front of lateral fossulae, very narrow in postocular emarginations. Lateral hyaline border
origin near midlength of lateral depressions, very narrow along posterior part of lateral depressions, wide at excavation,
very narrow around posterior margin. Anterior margin of pronotum straight in midregion, turned upward slightly in front
of lateral fossulae, postocular emarginations well developed. Lateral depressions broad, slightly convex in midregion,
coarsely, deeply punctate, interstices shallowly microreticulate; margins moderately arcuate, excavate at posterior;
pronotum constricted behind lateral depressions. Lateral fossulae deeply impressed, especially at anterior. Pronotal disc
convex, densely, deeply, moderately coarsely punctate, interstices shallowly microreticulate ridges. Median groove deeply
impressed in anterior and posterior, obsolete in midregion. Anterior foveae absent. Posterior foveae large, deeply
impressed. Posterolateral angles with broad depressions. Prosternum with low median ridge; coxae contiguous.
Metasternum with large median glabrous area. Elytra: Length 1.36 mm; maximum width (near midlength) 1.04 mm. Disc
convex, dull, shallowly microreticulate, with seven rows of ill-defined punctures between suture and humeri. Declivity
origin near posterior 0.33. Intervals costate, width slightly greater than puncture width. Explanate margin moderately
developed; right elytron crenulate in anterior 0.25 of margin, left elytron missing from specimen. Abdomen: Basal five
sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short
hairs. Legs: All legs moderately long and slender. Protarsomeres 1-3 with apparently unexpanded setae. Genitalia:
Aedeagus as illustrated (Fig. 141 C)( 1 examined).

Distribution. - (Figs, 142B,187B). Presently known only from the type-locality,
Temescaltepec, Mexico, Mexico.

Etymology. - Adjective, mexicanus , in reference to location of collection of the holotype.

48. Ochthebius reticulocostus new species
(Figs. 140A,141 A,142B,187B)

Type-locality. - Vicinity of San Antonio, between Toluca and Temascaltepec, Mexico,
Mexico.

Type-specimens. - The holotype male is deposited in USNM. It was collected by
H.P. Brown, October 11, 1966. The allotype, collected by B. Malkin, September 22, 1953, is
from Ixtlan del Rio, Nayarit, Mexico. It is also deposited in USNM.

Diagnosis. - Among those species of O. ( Asiobates ) whose adults lack discrete anterior
pronotal foveae, O. reticulocostus is distinctive by virtue of its markedly microreticulate
dorsum and costate elytral intervals. Smaller size, narrower form (Fig. 140A) and more
markedly developed microreticulation readily distinguish O. reticulocostus adults from those of

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395

Figs. 141 A - D, Aedeagi of Ochthebius holotypes. (A) O. reticulocostus. (B) O. orbus. (C) O. mexicanus. (D) O. apache.

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Figs. 142A - B, Geographical distributions of Ochthebius species. (A) O. similis •, O. apache ★ and O. angularidus
A ■ (B) O. reticulocostus • , 0. mexicanus ★ and O. apicalis A •

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397

O. mexicanus , the only other species of Asiobates characterized by costate, microreticulate
elytral intervals.

Description. — Form: Slightly truncate, moderately convex (Fig. 140A). Size: Holotype 1.64 mm long, 0.76 mm
wide. Color: Brown. Head: length 0.32 mm; width 0.48 mm. Frons densely, moderately coarsely punctate, markedly
microreticulate; interocular foveae deep and large, width of each nearly 0.66 distance between them; interocular tuberculi
large; basomedial foveae nearly as deep and as large as interocular foveae. Frontoclypeal suture evenly arcuate. Clypeus
length 0.50 width, sculpture as frons. Labroclypeal suture straight. Labrum length 0.33 width, microreticulate, moderately
emarginate. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of 3. Mentum width equal
length, shining, densely, moderately coarsely punctate; anterior margin arcuate. Submentum evenly, finely punctulate,
punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.40 mm;
maximum width (near anterior 0.33) 0.64 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in
front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin at anterior angles, extended
extremely narrowly along lateral depressions, wide at excavations, very narrow around posterior margin. Anterior margin
of pronotum very slightly produced in midline, with deep excavations in front of each lateral depression; anterior angles
obtuse. Lateral depressions flat, broad, densely, moderately coarsely punctate, markedly microreticulate; margins
moderately arcuate, excavated at posterior, tooth lateral to each excavation; pronotum constricted behind lateral
depressions. Lateral fossulae very deeply impressed, with well developed microreticulation; inner margin abrupt, posterior
extreme tapered into lateral hyaline border. Pronotal disc moderately convex, densely, moderately coarsely punctate,
subrugulose, markedly microreticulate, narrow ridges between punctures. Median groove narrow, moderately deeply
impressed, present in middle 0.50 of pronotum only, confluent in posterior with confluent posterior foveae. Anterior foveae
not apparent, this region rugulose with dense punctation. Posterior foveae deep, posterior extremes confluent in form of
U-shaped depression which is densely punctate and strongly microreticulate. Posterolateral angles with distinct
impressions. Prosternum with median carina ending at coxal cavities; coxae contiguous. Metasternum with moderately
large median glabrous area. Elytra: Length 1.08 mm; maximum width (near midlength) 0.76 mm. Disc convex, dull,
markedly microreticulate, with six rows of punctures between suture and humeri. Sides convex, declivity origin near
posterior 0.33; punctures round, intervals costate, strongly microreticulate, width equal puncture width, with fine
impressed lines; interstices between punctures 0.25 puncture length; each puncture with seta. Explanate margin weakly
developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous,
apical 0.50 with very fine, short hairs. Legs: Moderately long and slender; ratio of hind leg length to abdominal length
1. 8:1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male (Fig. 141 A)( 1 examined).

Distribution. - (Figs. 142B,187B) Presently known only from the states of Nayarit and
Mexico, Mexico.

Etymology. - Latin, reticulatus (net-like) plus costus (ridge). Named in reference to the
microreticulate dorsal surface and costate elytra.

49. Ochthebius apicalis Sharp
(Figs. 132A,142B,143A,B,187B)

Ochthebius apicalis Sharp, 1882:91 (lectotype male in BMNH, here designated; type-locality: Guatemala City,

Guatemala).

Diagnosis. - Distinctive by small size, lack of discrete anterior pronotal foveae, and
especially, fusiform body shape of adults.

Description. — Form: Fusiform, very convex (Fig. 132A). Size: Lectotype 1.60 mm long, 0.84 mm wide. Color:
Dorsum and venter red-brown; legs, palpi and antennae orange-brown. Head: Length 0.32 mm; width 0.44 mm. Frons
densely punctate, microreticulate; interocular foveae deep and large, width of each 0.66 distance separating them;
interocular tuberculi large; basomedial fovea smaller, shallower than interocular foveae. Frontoclypeal suture evenly
arcuate. Clypeus length 0.50 width; microreticulate, densely punctate, sparsely pubescent. Labroclypeal suture straight.
Labrum length 0.33 width, finely sparsely punctate, sparsely pubescent; anterior margin broadly emarginate, edge
upturned slightly along entire margin. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.50 length of 3.
Mentum width equal length, shining, finely sparsely punctate, anterior margin arcuate. Submentum evenly, finely
punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline
0.42 mm; maximum width (near anterior 0.33) 0.64 mm. Anterior hyaline border moderately wide in front of disc, slightly
wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin at anterior angles, extended
very narrowly along lateral depressions, wide at excavations, very narrow around posterior margin. Anterior margin of
pronotum slightly produced in middle, deep excavations in front of each lateral depression; anterior angles acute. Lateral
depressions flat, broad, densely punctate, microreticulate; margins moderately arcuate, posterior excavate, small tooth
lateral to excavation; pronotum quite constricted behind lateral depressions. Lateral fossulae deeply impressed,

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Figs. 143A - D, Aedeagi of Ochthebius species. (A) O. apicalis, Chiapas, Mexico. (B) O. apicalis, Cordoba, Veracruz,
Mexico. (C) O. browni, holotype. (D) O. batesoni, Galapagos Islands, Ecuador.

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microreticulate; inner margin abrupt, posterior extreme tapered into lateral hyaline border. Pronotal disc markedly
convex, densely, moderately coarsely punctate, punctures separated by thin walls. Median groove deep, wide,
microreticulate. Anterior foveae absent, this region densely punctate, slightly depressed. Posterior foveae large, deep,
punctate and microreticulate. Posterolateral angles with distinct impressions. Prosternum with median carina ended at
coxal cavities; coxae contiguous. Metasternum with large median glabrous area. Elytra: Length 1.00 mm; maximum
width (near midlength) 0.80 mm. Disc markedly convex, with depression in midregion, moderately shiny, with six rows
of round punctures between suture and humeri. Sides convex, declivity origin near midlength; intervals rounded,
moderately elevated, width equal puncture width, surface smooth; interstices between punctures 0.25 puncture length;
each puncture with seta. Explanate margin slightly developed. Abdomen: Basal five sterna with hydrofuge pubescence.
Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and
slender; ratio of hind leg length to abdominal length 1.7: 1.0. Protarsomeres 1-3 with suction setae. Genitalia: Male
(Figs. 143A,B)(9 examined).

Variation. - The lectotype aedeagus has the apical piece shriveled slightly, but is definitely
of the form I have illustrated (Fig. 143 A) using a specimen from Mexico, Chiapas, 27 mi. N.
Bochil. The specimens from the latter locality and lectotype have the elytral intervals somewhat
less elevated than the specimens from Mexico, Cordoba. The aedeagus of the Cordoba
specimen (Fig. 143B) is also slightly different, having the apical piece broader and the
preterminal process directed toward the parameres. However, based upon variations in external
and genitalic structure in other species which are represented by numerous specimens from
many localities, I feel these two forms are conspecific, although probably diverging. Males are
easily differentiated from females by the large protarsal pads of suction setae. Ten specimens
were studied in addition to the lectotype (see appendix).

Natural History. - I have collected adults of this species, together with those of Hydraena
splecoma, at the sandy margins of an overflow puddle bordering a forest stream in Mexico,
Chiapas, 27 miles N. of Bochil (Figs. 190A,B).

Distribution. - (Figs. 142B,187B). Presently known only from the mountains of southern
Mexico and Guatemala.

The puncticollis Group

Members of the puncticollis Group are characterized by large size (ca. 2.10-2.80 mm long)
and aedeagal structure, which has the apical piece large and tapered to the apex
(Figs. 144A-E). Additionally, the median portion of the aedeagus gradually tapers to its distal
end and, therefore, is widest (in both dorsal and lateral views) well before the apex. Parameres
are positioned in different planes, not side by side for their entire length.

The group presently includes four very distinct species. Two of these species, O. leechi and
O. martini , are restricted to a few localities in California; one, O. puncticollis , is widely
distributed in California, and known from a few localities in Baja California, Arizona and
Utah; the fourth species, O. angularidus , is restricted to the Rio Grande River drainage in
Texas and Mexico.

50. Ochthebius puncticollis LeConte
(Figs. 2B,D,133A,135C,144B,151D,185A)

Ochthebius puncticollis LeConte, 1852:210 (lectotype female in MCZ, here designated; type-locality: Tucson, Arizona,
U.S.A). - LeConte, 1855:361. - LeConte, 1878:378. - Horn, 1890:21. - Fall, 1919:213. - Leech and Chandler,
1956:333. -Perkins, 1976:314.

The type-series in the LeConte collection at the MCZ consists of eight specimens, the first
two of which have “Type 3133” labels. The first four specimens are conspecific and all are

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females. The last four specimens are mounted together on a card and belong to O. rectus
LeConte. The first specimen, a female, is lectotype, and is labelled accordingly.

Diagnosis. - The large adults included in this species are most similar to those of O.
angularidus and O. martini , but differ from the former by lack of angulate lateral depressions
and from the latter by lack of broadly explanate elytra (Figs. 133A,136A,C).

Description. — Form: Ovate, very convex (Fig. 133A). Size: Lectotype 2.16 mm long, 1.04 mm wide. Color:
Dorsum dark brown with slight metallic green tint; venter dark brown, legs and palpi brown. Head: Length 0.46 mm;
width 0.62 mm. Frons moderately densely, moderately coarsely, shallowly punctate, prominently pubescent, extremely
finely microreticulate; interocular foveae deep and large, width of each 0.66 distance between them; interocular tuberculi
large, basomedial foveae nearly as large as interocular foveae, shallower. Frontoclypeal suture evenly arcuate. Clypeus
length 0.50 width; sculpture and pubescence as frons. Labroclypeal suture straight. Labrum length 0.33 width; densely
pubescent; median emargination deep, anterior 0.50 of labrum bilobed, lobes at angle to remainder of labrum. Maxillary
palpus with palpomere 3 moderately wide; palpomere 4 0.25 length of penultimate. Mentum width equal length, dull,
densely moderately coarsely punctate, markedly microreticulate; anterior margin arcuate. Submentum evenly, finely
punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline
0.60 mm; maximum width (near anterior 0.33) 0.88 mm. Anterior hyaline border moderately wide in front of disc, slightly
wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin at anterior angles, extended
narrowly along lateral depressions, wide at excavation, very narrow around posterior margin. Anterior margin of pronotum
very slightly produced in middle, excavate in front of lateral fossulae and lateral depressions, tooth between excavations;
anterior angles acute. Lateral depressions slightly inflated, broad, coarsely densely punctate, prominently pubescent;
margins moderately arcuate; excavate at posterior, tooth lateral to excavation; pronotum markedly constricted behind
lateral depressions. Lateral fossulae very deeply impressed, very finely microreticulate; inner margin abrupt, posterior
extreme tapered into lateral hyaline border. Pronotal disc moderately convex, moderately sparsely, moderately coarsely,
shallowly punctate, punctures separated by one-two times puncture diameter; extremely finely, effacedly microreticulate
over entire surface. Median groove long, narrow, shallow, extended from anterior and posterior border, tapered at ends.
Anterior foveae large, deep, somewhat S-shaped, extremely finely microreticulate. Posterior foveae moderately large,
approximately equal in size and depth to anterior foveae, somewhat teardrop-shaped. Anterior and posterior foveae of a
side united by shallow groove, together in form of sinuate depression. Posterolateral angles without distinct impressions.
Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with very large median glabrous
area. Elytra: Length 1.40 mm; maximum width (near midlength) 1.04 mm. Disc convex, moderately dull, with six rows of
round punctures between suture and humeri. Sides very convex, declivity origin near posterior 0.33; intervals rounded,
width equal puncture width, with extremely fine, impressed lines; interstices between punctures 0.50 puncture length; each
puncture with seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence.
Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and stout;
ratio of hind leg length to abdominal length 1.8: 1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male
(Fig. 1 44B)(2 1 examined).

Variation. - Some specimens lack the channel joining anterior and posterior foveae. Males
of this species have very small protarsal suction setae and have the lobes of the labrum
moderately upturned, whereas females lack expanded protarsal setae and have the lobes
slightly upturned, if at all. I have examined 219 specimens (see appendix).

Natural History. - Specimens are typically collected at the margins of streams with sandy
banks composed of well-sorted, relatively large particles. Refer to Perkins (1976) for a
discussion of microhabitat preferences.

Distribution. - (Figs. 135C,185A). Southwestern United States and adjacent Baja
California; in California apparently restricted to coastal mountain ranges; not yet known from
the Sierra Nevada mountains.

51. Ochthebius martini Fall
(Figs. 135C,136C,144D,E,185A)

Ochthebius martini Fall, 1919:212 (holotype male in MCZ; type-locality: Redwood Park, California). - Leech and

Chandler, 1956:333.

I have dissected the holotype, a slightly teneral male, and placed the aedeagus in a microvial
affixed to the pin.

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401

Figs. 144A - E, Aedeagi of Ochthebius species. (A) O. leechi, holotype. (B) O. puncticollis, Marin County, California. (C)
O. angularidus, holotype. (D) O. martini , Humboldt County, California. (E) O. martini, holotype.

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Perkins

Diagnosis. - Broadly explanate elytra, convergent lateral hyaline borders and unusual
habitus serve as recognition characteristics for adults of this very distinctive species
(Fig. 136C).

Description. — Form: Broadly ovate, convex (Fig. 136C). Size: Holotype 2.12 mm long, 1.12 mm wide. Color:
Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.50 mm; width 0.66 mm. Frons sparsely punctate,
markedly, extremely finely microreticulate, prominently pubescent; interocular foveae deep and large, width of each nearly
0.66 distance between them; interocular tuberculi small; basomedial foveae nearly as large as interocular foveae,
shallower. Frontoclypeal suture evenly arcuate. Clypeus length 0.50 width; strongly finely microreticulate; moderately
pubescent. Labroclypeal suture straight. Labrum length 0.33 width; microreticulate, densely pubescent; 0.50 median
emargination deep and broad, anterior 0.50 two lobes at angle to remainder of labrum. Maxillary palpus with palpomere 3
moderately wide; palpomere 4 0.25 length of 3. Mentum trapezoidal, dull, microreticulate; anterior margin arcuate.
Submentum evenly, finely punctulate, punctures contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax:
Pronotum length at midline 0.68 mm; maximum width (near anterior 0.33) 0.96 mm. Anterior hyaline border wide in
front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin at
anterior angles, width increased along contour of lateral depression, thence straight to posterior angles, very narrow around
posterior margin. Anterior margin of pronotum very slightly produced in middle, moderately excavate in front of lateral
fossulae, more deeply excavate in front of lateral depressions, pronounced tooth between excavations; anterior angles acute.
Lateral depressions slightly inflated, densely coarsely punctate, moderately pubescent; margins moderately arcuate,
posterior excavate, tooth lateral to excavation; pronotum markedly constricted behind lateral depressions. Lateral fossulae
deeply impressed, markedly finely microreticulate; inner margin abrupt, posterior extreme tapered into lateral hyaline
border. Pronotal disc markedly convex, moderately coarsely, moderately densely punctate, punctures separated by one-two
times puncture diameter; moderately pubescent; surface between punctures finely microreticulate. Median groove
extremely narrow, shallow. Anterior foveae small, moderately deep, microreticulate, separated from median groove by
1.50 times fovea width. Posterior foveae narrow, oblique lines, microreticulate, posterior extreme of each fovea separated
from median groove by four-five times fovea width. Posterolateral angles without impressions. Prosternum with median
carina ended at coxal cavities; coxae contiguous. Metasternum with very large median glabrous area. Elytra: Length
1 .44 mm; maximum width (near midlength) 1.12 mm. Disc very convex, moderately dull, with six rows of round punctures
between suture and humeri. Sides convex, declivity origin slightly past midlength; intervals flat, extremely finely
microreticulate; width equal puncture width; interstices between punctures 0.25 puncture length; each puncture with seta.
Explanate margin very broad. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two segments smooth, basal
0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and stout; ratio of hind leg length to
abdominal length 2.0: 1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male (Figs. 144D,E)(5 examined).

Variation. - Aedeagi of specimens from Humboldt County, California differ slightly from
the norm (Fig, 144D). Externally, these specimens are slightly less convex, have slightly larger
pronotal foveae, and have less explanate elytra than specimens from the remainder of the
range.

Natural History. - Convex body form and close phylogenetic relationship to O. puncticollis
lead me to speculate that O. martini adults require streambanks with well-sorted, relatively
large particles. Refer to Perkins (1976) for a discussion of the microhabitat preferences of O.
puncticollis.

Distribution. - (Figs. 135C,185A). Restricted to the coastal mountains of northern
California between Santa Cruz and Humboldt Counties.

Remarks. - This species is apparently quite rare, as a total of only 44 specimens (including
holotype) were seen, despite the rather intensive collecting efforts, especially by Hugh B.
Leech, in its range (see appendix).

52. Ochthebius angularidus new species
(Figs. 96C,136A,142A,144C,185A)

Type-locality. - Rio San Rodrigo, El Remolino near San Carlos, Coahuila, Mexico.

Type-specimens. - The holotype male and allotype with same locality data are deposited in
USNM. These specimens were collected by Harley P. Brown, May 27, 1969. Data about
paratypes (26) are presented in the appendix.

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403

Diagnosis. - O. angularidus is readily distinguished from other New World species of the
subgenus Asiobates by the angulate lateral depressions of the pronotum (Figs. 96C,136A).

Description. — Form: Ovate, moderately convex (Fig. 136A). Size: Holotype 2.12 mm long, 1.00 mm wide. Color:
Dorsum and venter dark brown; legs and palpi brown. Head: Length 0.40 mm; width 0.56 mm. Frons rugulose, markedly
microreticulate, prominently pubescent; interocular foveae deep and large, width of each nearly 0.66 distance between
them; interocular tuberculi large, basomedial foveae nearly as large as interocular foveae, shallower. Frontoclypeal suture
slightly bisinuate. Clypeus length 0.50 width; anterior angles produced; densely, moderately coarsely punctate, punctures
microreticulate; prominently pubescent. Labroclypeal suture straight. Labrum length 0.33 width; microreticulate,
markedly pubescent; emargination deep, medially, lateral lobes bent at angle to remainder of labrum. Maxillary palpus
with palpomere 3 moderately wide; palpomere 4 slightly less than 0.50 length of 3. Mentum width equal length, rugulose
microreticulate, prominently pubescent; anterior margin arcuate. Submentum evenly, finely punctulate, punctures
contiguous. Genae shining, swollen. Postgena finely punctulate. Thorax: Pronotum length at midline 0.52 mm; maximum
width (near anterior 0.33) 0.78 mm. Anterior hyaline border moderately wide in front of disc, slightly wider in front of
lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin at produced tooth at midlength of lateral
depression, extended narrowly along posterior 0.50 of lateral depression, wide at excavation, very narrow around posterior
margin. Anterior margin of pronotum very slightly produced in middle, shallowly excavate in front of each lateral fossula
and in front of each lateral depression, small tooth between excavations; anterior angles acute. Lateral depressions slightly
inflated, broad, rugulose and prominently pubescent; margins excavate in anterior 0.50, in form of tooth at midlength of
lateral depression; extreme posterior excavate, prominent tooth lateral to excavation; pronotum markedly constricted
behind lateral depressions. Lateral fossulae deeply impressed, markedly microreticulate; inner margin abrupt, posterior
extreme tapered into lateral hyaline border. Pronotal disc rather flat, densely, moderately coarsely punctate,
microreticulate within punctures, prominently pubescent; surfaces between punctures shiny. Median groove deep, broad,
impunctate, markedly microreticulate. Anterior foveae large, deep, oval, width equal to distance between fovea and
median groove; markedly microreticulate. Posterior foveae large, deep, markedly microreticulate. Posterolateral angles
sloped. Prosternum with median carina ended at coxal cavities; coxae contiguous. Metasternum with large median
glabrous area. Elytra: Length 1.40 mm; maximum width (near midlength) 1.00 mm. Disc convex, moderately shiny, with
six rows of round punctures between suture and humeri. Sides convex, declivity origin slightly past midlength; intervals
flat, width equal puncture width, surface smooth; interstices between punctures 0.25 puncture diameter; each puncture
with seta. Explanate margin moderately developed. Abdomen: Basal five sterna with hydrofuge pubescence. Apical two
segments smooth, basal 0.50 glabrous, apical 0.50 with very fine, short hairs. Legs: Moderately long and stout; ratio of
hind leg length to abdominal length 1. 8:1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 1 44C)( 1 1
examined).

Natural History. - These beetles are apparently restricted to desert streams. Harley
P. Brown informs me (in litt.) that the holotype locality was “Site of an old mill; spring-fed
stream with travertine. Lutrochus abundant. Psephenus t exanus present. Most abundant
elmids: Hexacylloepus, Microcylloepus."

Distribution. - (Figs. 142A,185A). Northeastern Mexico and adjacent areas of Texas.

Etymology. - Latin, angulus (corner) plus aridus (dry). Named in reference to the desert
habitat of this species and its angulate lateral pronotal depressions.

53. Ochthebius leechi Wood and Perkins
(Figs. 133C,135C,144A,185A)

Ochthebius leechi Wood and Perkins, 1978:53 (holotype male in CAS; type-locality: Salt Creek at Stony Creek, N. of

Stonyford, Glenn County, California, U.S.A.)

Diagnosis. - O. leechi adults are readily distinguished from those of the other three species
in the puncticollis Group by absence of pronotal postocular emarginations (cf.
Figs. 133A,C,136A,C). The body form of O. leechi is most similar to that of O. puncticollis ,
but the former is longer (2.50 vs. 2.20 mm), less convex and has a greater elytral
length/ pronotal length ratio.

Description. — Form: Ovate, moderately convex (Fig. 133C). Size : Holotype 2.43 mm long, 1.20 mm wide. Color:
Dorsum dark brown to black; venter dark brown, legs and palpi brown. Head: Length 0.44 mm; width 0.60 mm. Frons
coarsely densely punctate; interocular foveae deep and large, width of each 0.50 distance between them; interocular
tuberculi indistinct, basomedial fovea contiguous with interocular foveae. Frontoclypeal suture slightly angulate. Clypeus
length slightly less than 0.50 width; sculpture as frons; anterior angles slightly produced. Labroclypeal suture straight.

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Figs. 145 A - C, Neochthebius vandykei. (A) pronotum. (B) head, ventral aspect. (C) head, lateral aspect.

Labrum length 0.50 width; emargination deep, medially, lateral lobes 0.50 length of labrum, at angle to remainder of
labrum. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 0.25 length of 3. Mentum width equal
length, coarsely punctate; anterior margin arcuate. Submentum coarsely punctate. Genae shining, swollen. Postgena
finely punctulate. Thorax: Pronotum length at midline 0.58 mm; maximum width (near anterior 0.33) 0.86 mm.
Anterior hyaline border narrow in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior
angles. Lateral hyaline border origin at anterior angles, extended narrowly along lateral depressions, wide at excavation,
very narrow around posterior margin. Anterior margin of pronotum straight, postocular emarginations absent. Lateral
depressions very slightly inflated, broad, coarsely densely punctate, sparsely pubescent; margins weakly arcuate;
excavate at posterior, without tooth lateral to excavation; pronotum moderately markedly constricted behind lateral
depressions. Lateral fossulae deeply impressed, shallowly microreticulate; inner margin abrupt, posterior extreme
tapered into lateral hyaline border. Pronotal disc slightly convex, coarsely punctate, punctures separated by puncture
diameter. Median groove long, moderately wide and deep, microreticulate, tapered at ends. Anterior foveae moderately
large, rugulose. Posterior foveae moderately large, shallowly impressed, microreticulate. Prosternum with low median
carina ended at coxal cavities, coxae contiguous. Metasternum with very large median glabrous area. Elytra: Length
1.72 mm; maximum width (near midlength) 1.20 mm. Disc convex, moderately dull, with six rows of round punctures
between suture and humeri; rows shallowly striate. Sides very convex, declivity origin near posterior 0.33; intervals

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405

Figs. 146A - D. (A) Meropathus vectis, body outline. (B) Neochthebius vandykei, body outline. (C) M. vectis,
spermatheca. (D) TV. vandykei aedeagus, San Mateo County, California (inset: Brunswick, British Columbia, Canada).

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Perkins

rounded, width equal puncture width, with extremely finely impressed lines and irregularities; interstices between
punctures 0.50 puncture length; each puncture with seta. Explanate margin moderately developed. Abdomen: Basal five
sterna with hydrofuge pubescence. Apical two sterna sparsely pubescent. Legs: Moderately long and stout; ratio of hind
leg length to abdominal length 1.8: 1.0. Protarsomeres 1-3 without suction setae. Genitalia: Male (Fig. 1 44A)( 1 4
examined).

Variation. - Body length ranges from 2.40 to 2.72 mm, with most specimens approximately
2.50 mm long. Females lack the upturned labral lobes seen in males. I have examined 96
specimens (see appendix).

Natural History. - I have collected this species from the stream at Wilbur Hot Springs,
Colusa County, California. The water was warm to the touch, but no temperature
measurements were made. The specimens were found by stirring the substratum, which
consisted of sand, pebbles and rocks. The slope angle of the bank was low, and the beetles were
taken near the waterline. Elsewhere (Perkins, 1976) I have demonstrated that O. puncticollis
lives as much as 36 inches from the waterline in stream banks with well sorted particles. I
suggested that the convexity of O. puncticollis was one of the more important factors among
the composite of biological and physical interractions which result in the observed microhabitat
distributions of this species. One of the obvious differences between O. puncticollis and O.
leechi is the more convex body of the former. Perhaps these two environmental factors, water
temperature and substrate particle size, have played a major role in the differentiation of
species in the puncticollis Group.

Distribution. - (Figs. 135C,185A). Northwestern California.

GENUS MEROPATHUS ENDERLEIN

Meropathus Enderlein, 1901:121 (type-species: Meropathus chuni Enderlein). - d’Orchymont, 1938a:78. - Jeannel, 1940:

129. - Brookes, 1951:28. - Gressitt and Samuelson, 1964: 376. Samuelson, 1964:624. - Janssens, 1967a:3. - Ordish,

1971:185.

Discussion. - Meropathus is a distinctive genus whose adults are characterized by rough
elytra with ridges of various sorts and with stiff, recumbent setae which are also present on the
head and pronotum. Body form (Fig. 146A) is also distinctive, as is the short metasternum.

According to current data, the genus is restricted to eastern Australia (3 species) (Janssens,
1967a), islands of the New Zealand subregion (3 species) (Brookes, 1951; Gressett and
Samuelson, 1964; Ordish, 1971), and the island group consisting of Prince Edward Islands,
Kerguelen Island and Heard Island (1 species) (Enderlein, 1901; d’Orchymont, 1938; Jeannel,
1940; Janssens, 1967a).

The description herein of M. vectis , from Isla de los Estados and the Falkland Islands at the
tip of South America (Fig. 87B), constitutes the first mention of a member of Meropathus
from the Western Hemisphere and completes the circum-polar pattern of distribution. The
relative locations are such that if one draws a line connecting the insular populations, that is,
from Isla de los Estados to the Kerguelen Island vicinity, to the Campbell Island vicinity, and
back again to Isla de los Estados, an (approximate) equilateral triangle is formed, the center of
which is very near the South Pole. Further comments on zoogeography are presented in the
section on that topic.

Adults of this genus are apparently only semi-aquatic, the insular species being found in
coastal areas around stones, moss, grass tussocks and bird nests, whereas available data for the
Australian species indicates moist streamside habitats such as foam near waterfalls (Janssens,
1967) or debris beneath tree ferns near streams and waterfalls (Deane, 1931). For more

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407

detailed notes on the habitat of this genus on subantarctic islands, the reader is referred to
Ordish (1971). The single specimen of M. vectis from the Falkland Islands has the label
notation, “in Poa flabellatum tussock”; habitat data are not available for the two specimens
from Isla de los Estados.

D’Orchymont (1938a) presented a rather thorough review of structural features of M.
chuni, to document his opinion that Meropathus was not of equal rank with Ochthebius. He,
therefore, ranked the former as a subgenus of the latter while also indicating a number of
similarities between Meropathus and Neochthebius (the latter he considered of subgeneric
rank also).

Following his morphological treatise on Meropathus d’Orchymont (1938a:89) makes the
following statement: “Je n’ai pu examiner l’edeage; je craignais d’abimer eventuellement par
une dissection le seul male que j’ai vu et qui appartient as Museum de Paris. II n’est pas
douteux toutefois que cet organe doive etre conforme comme celue des Ochthebius , pourvu par
consequent de deux parameres.”

Two years later, much to d’Orchymont’s chagrin, I would imagine, Jeannel (1940)
demonstrated that the aedeagus, in fact, did lack parameres. D’Orchymont’s opinion of the
proper rank for Meropathus did not change however, as he (1943b:39) makes the following
remark in a footnote: “C’est a tort que R. Jeannel vient d’accorder de nouveau rang generique a
Meropathus. Cette appreciation est basee uniquement sur une erreur fondamentale de
morphologie phallique, a savoir que las Hydraena seraient depourvues de parametres a
l’edeage. Ceci n’est vrai que pour les Haenydra. Les autres, les Hydraena (sensu stricto) entre
autres, ont au contraire des parameres bien developpes. La meme chose se presente chez
Limnebius ( Bilimneus ) (depourvu) et Limnebius (sensu stricto) (pourvu de parameres). Ce qui
n’empeche que ces subdivisions ne sont a considerer que comme des sou-genres.”

All other authors (Brookes, 1951; Gressitt and Samuelson, 1964; Janssens, 1967; Ordish,
1971) have, nevertheless, considered Meropathus a valid genus (as do I), but have not
attempted to resolve its position within the Hydraenidae, or even within Ochthebius (sensu
d’Orchymont).

By the shape of the maxillary palpi, Meropathus is clearly closely related (within the
Hydraenidae) to Ochthebius , (sensu stricto). However, the antennae and other characteristics
indicate an even closer relationship to Neochthebius , a relationship which d’Orchymont
(1938a) recognized, but did not reflect in his ranking (refer to Neochthebius for additional
comments). It appears, therefore, that d’Orchymont in his broad concept of Ochthebius ,
afforded equal rank (subgenera) to groups which varied in their phylogenetic proximity to
Ochthebius (in the very strictest sense, i.e., that group which contains O. marinus (Paykull),
the type of the genus).

It becomes evident, therefore, that the concept “ Ochthebius ” ( sensu d’Orchymont) is used
to best advantage when treated as a suprageneric category, thereby permitting equal ranking to
lineages which appear, based upon many considerations from which phylogeny is inferred, to
warrant that ranking (refer to the sections on phylogeny for additional comments).

1. Meropathus vectis new species
(Figs. 87B,146A,C,151A,B)

Type-locality. - Puerto San Juan, Isla de los Estados, Argentina.

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Perkins

Type-specimens. - The holotype female is deposited in USNM. One female paratype from
Bahia Blossom on the same island is also deposited in USNM. These two specimens were
collected by O.S. Flint and G.F. Hevel May, 1971. One additional female paratype, deposited
in BMNH, has the following data: E. Falkland Is., Kidney Is., 30-XI-1961, M. Holdgate, in
Poa flabellatum tussock.

Diagnosis. - Adults are intermediate in development of dorsal roughness and pubescence
between the very rugose, strongly pubescent adults of M. campbellensis Brookes (Campbell
Island) and the smoother, less pubescent adults of M. chuni Enderlein (Kerguelen Islands). M.
vectis may be distinguished from M. campbellensis by the following: 1) borders of the pronotal
median depression are costiform and with long hairs which form distinct lines in M.
campbellensis, whereas the borders in M. vectis are rounded, with much shorter hairs which do
not form distinct lines; 2) the median depression is rugose in M. campbellensis, microreticulate
in M. vectis’, 3) the elytra of M. campbellensis have three pubescent tubercles on the suture,
one just behind the scutellum, one at midlength, and one at the apical 0.25, M. vectis lacks
these tubercles. M. chuni can be distinguished from the previous two species by the cariniform
elytral suture and much reduced dorsal pubescence.

Description. — Form: Elongate oval, convex (Fig. 146A). Size: Holotype 2.32 mm long, 1.00 mm wide. Color:
Black. Head: Length 0.40 mm; width 0.68 mm. Frons semi-rugulose, moderately pubescent on reliefs; interocular foveae
deep, width of each 0.50 distance between them; interocular tuberculi large, pubescent. Frontoclypeal suture bisinuate.
Clypeus length nearly 0.33 width, microreticulate. Labroclypeal suture straight. Labrum length 0.50 width; surface much
smoother than cLypeus, shining; anterior emargination nearly 0.25 length of labrum. Maxillary palpus with palpomere 3
moderately wide; palpomere 4 0.75 length of 3. Mentum rectangular width 0.61 length, finely microreticulate.
Submentum finely punctulate. Genae swollen in midregion, depressed laterally, punctulate. Postgena punctulate. Thorax:
Pronotum length at midline 0.66 mm; maximum width (near anterior 0.33) 0.86 mm; moderately pubescent on reliefs,
markedly microreticulate, semi-rugulose throughout; anterior margin straight, with thin semi-transparent border; median
depression wider in anterior 0.50, margins rounded; large tubercle each side of posterior 0.50 of median depression; large
tubercle and oval depression on each side of anterior 0.50 of median depression; posterior margin slightly arcuate to rear,
with thin semi-transparent border. Prosternum shallowly depressed in front of coxae; coxae contiguous. Metasternum
depressed in midline, hydrofuge pubescent. Elytra: Length 1.20 mm; maximum width (near midlength) 0.80 mm. Wings
absent, elytra interlocked. Each elytron with large, deep depression median to humerus and shallower, smaller one at
midlength near suture. Margin and much of surface with thick hook-shaped setae. Each elytron with two low tubercles in
posterior 0.50. Explanate margin well developed, especially near apices. Abdomen: Sterna hydrofuge pubescent. Hairs on
sternum 6 much longer than those of other sterna. Legs: Of moderate length and build. Genitalia: Male unknown; female
(Fig. 146C)(3 examined) (note: the spermatheca illustrated is from the Falkland Island specimen, which was the best
preparation of the three).

Variation. - The specimen from the Falkland Islands is slightly more pubescent and has the
elytral tubercles somewhat larger than the two specimens from Isla de los Estados. Aedeagi of
males from both localities must be studied to determine with certainty that these two
populations are not conspecific.

Natural History. - The specimen from the Falkland Islands was found “in Poa flabellatum
tussock”.

Distribution. - (Fig. 87B). Isla de los Estados, Argentina, and the Falkland Islands.

Etymology. - Latin, vectis (rider). This species has reached its present distribution by riding
on either marine birds or drifting land masses, probably the latter.

GENUS NEOCHTHEBIUS D’ORCHYMONT

Neochthebius d’Orchymont, 1932a:42 (type-species: Ochthebius vandykei Knisch; new status). - Van Dyke, 1918:306. -
Knish, 1924:31. - d’Orchymont, 1932a:42. - d’Orchymont, 1938a:83. - Leech and Chandler, 1956:333. - Hatch,

Western Hemisphere Hydraenidae

409

1965:20.

Discussion. - D’Orchymont (1932a) established a new subgenus, Neochthebius, for the
unusual intertidal hydraenid, Ochthebius vandykei Knisch. This unusual beetle is distributed
along the Pacific Coast of North America from British Columbia to southern California
(Fig. 139C), living in crevices of rocks in the intertidal zone (Van Dyke, 1918). It is the only
Western Hemisphere hydraenid occupying such a habitat. The Japanese species, Ochthebius
granulosus Sato 1963, also a member of Neochthebius , is closely related to N. vandykei and is
also a member of the intertidal fauna. D’Orchymont (1932a) compared Neochthebius to
Cobolius, Acanthochthebius, Dory ochthebius and Calobius , all of which he considered
subgenera of Ochthebius. (Janssens (1969) has subsequently combined Doryochthebius and
Calobius- see section on Ochthebius ).

However, in a later paper detailing his reasons for ranking Meropathus as a subgenus,
d’Orchymont (1938a) compared Neochthebius closely to Meropathus and contrasted them
both to Henicocerus (all of which he considered of equal, subgeneric rank).

Similarities between adults of Neochthebius and Meropathus which d’Orchymont
emphasized were the antennae and, in passing, the short metasternum and short, stout tarsi.
The antennae of the two groups are very similar, having a characteristic globose shaped
antennomere 2 (Figs. 145B,C). In addition to the short metasternum, the eyes of both groups
are much smaller than other Ochthebius (sensu d’Orchymont) and have larger, more convex
facets (Figs. 145B,C). Additionally, both groups are apterous and have 1) a markedly
microreticulate, median longitudinal depression on the pronotum, 2) rugulose elytra which are
fused at the suture, 3) reduced metanotum, and 4) short, stout tarsi. In fact, even the body form
of Neochthebius and Meropathus (Figs. 146A,B) are very suggestive of a close relationship.
Add to these morphological resemblances the similarities in habitats of Neochthebius
(intertidal) and Meropathus (coastal), and the close relationship becomes almost undeniable.

The more highly derived character states of Meropathus, however, make the two groups
quite dissimilar. The most obvious difference is development of dorsal sculpture and pubescence
in Meropathus, which has elevated carinae and mounds on the elytra and pronotum covered
with stiff, recumbent setae. Neochthebius adults (Fig. 145 A) are much less markedly
sculptured, and much flatter. Finally, differences in the aedeagus between males of
Neochthebius (with parameres) and Meropathus (lacking parameres), validate separate
generic status for the two groups.

From the features described above, many of which are obviously of a derived nature, it is
apparent that Neochthebius-Meropathus form a sub-lineage within Ochthebius (sensu
d’Orchymont), whereas the other subgenera of the group (e.g., Ochthebius, Asiobates,
Henicocerus, Calobius, etc.) form another, larger sublineage.

Males of all subunits of Ochthebius (sensu d’Orchymont), except Meropathus, have
parameres, however, this being a plesiotypic state it cannot be used to unite Neochthebius to
the other subunits with this non-derived condition.

Recognizing Neochthebius and Meropathus of equal (generic) rank with Ochthebius
reflects the two monophyletic lineages ( Ochthebius and Neochthebius-Meropathus ) and also
emphasizes the divergence of Meropathus. (Formally naming the suprageneric groups
represented by the two lineages is, in my opinion, unnecessary at this time). Additionally, it
predicts absence of transitional stages between Neochthebius and Meropathus, while indicating
lack of evidence for two discrete lineages within Ochthebius. Should further study reveal
constant morphological features from which could be inferred two major lineages arising

Quaest. Ent., 1980, 16 (1,2)

410

Perkins

basally within Ochthebius then both sublineages would warrant equal (generic) ranking with
Meropathus and Neochthebius (Asiobates may be such a sublineage - refer to the discussion
section of Ochthebius).

That the sublineage Neochthebius-Meropathus has its origin basally in the broader lineage
is inferred from the austral Gondwanian pattern of distribution of Meropathus (see sections on
Meropathus and phylogeny).

1. Neochthebius vandykei (Knisch)

(Figs. 139C,145A-C,146B,D,198A-C)

Ochthebius vandykei Knisch, 1924:31 ( nomen novum). - d’Orchymont, 1932:42. - d’Orchymont, 1943:40. - Leech and
Chandler, 1956:333.

Ochthebius lapidicolus Van Dyke (not Wollaston), 1918:306 (holotype female in CAS; type-locality: Moss Beach, San
Mateo County, California).

Diagnosis. - This small blackish species is easily distinguished by virtue of its narrow body
form, dull, strongly microreticulate dorsum, and intertidal habitat.

Description. — Form: Elongate. Size: Holotype 1.64 mm long, 0.60 mm wide. Color: Dorsum and venter dull black,
legs dark brown. Head: Length 0.30 mm; width 0.42 mm. Frons markedly microreticulate; interocular foveae deep and
large, width of each nearly 0.66 distance between them; interocular tuberculi very small; basomedial fovea very shallow.
Frontoclypeal suture evenly arcuate. Clypeus strongly microreticulate, length 0.50 width. Labroclypeal suture straight.
Labrum microreticulate, length 0.50 width; median emargination shallow. Maxillary palpus with palpomere 3 short, wide;
palpomere 4 nearly 0.66 length of 3. Mentum longer than wide, shiny, microreticulate; anterior margin arcuate.
Submentum microreticulate. Genae dull, swollen. Postgena finely punctulate. Eyes small, facets relatively large. Thorax:
Pronotum (Fig. 145A) length at midline 0.44 mm; maximum width (near anterior 0.33) 0.50 mm. Anterior hyaline border
very narrow, slightly arcuate to rear. Lateral hyaline border absent. Posterior hyaline border very narrow. Anterior margin
of pronotum very slightly arcuate to rear; anterior angles obtuse. Lateral depressions wide, slightly convex, markedly
microreticulate. Lateral fossulae moderately deeply impressed, with well developed microreticulation; inner margin
abrupt. Pronotal disc markedly microreticulate, with lyre-shaped impression and faint median longitudinal depression.
Posterolateral angles with shallow impressions. Prosternum with low median ridge; coxae narrowly separated.
Metasternum with small median glabrous area. Elytra: Length 1.04 mm; maximum width (near midlength) 0.60 mm.
Disc dull, rugulose, with ill-defined rows of punctures, each puncture with distinctive decumbent seta. Abdomen: Basal five
sterna with hydrofuge pubescence. Apical two segments smooth, basal 0.50 glabrous, apical 0.50 with fine hairs. Legs:
Moderately long and stout. Genitalia: Aedeagus as illustrated (Fig. 146D)( 10 examined).

Variation. - Specimens from British Columbia are generally larger (about 1.72 mm long)
and more markedly sculptured than those from California. The aedeagal apex (Fig. 146D) of
British Columbia morphs differs very slightly from that of California morphs. Sexes of this
species are differentiated by the row of stout spines bordering the last abdominal segment of
females; these spines are absent from males.

Distribution. - (Fig. 139C). Intertidal zone of rocky coastlines from British Columbia to
southern California. I have examined 257 specimens (see appendix).

PHYLOGENETIC RELATIONSHIPS AND ZOOGEOGRAPHY

Phylogenetic Relationships of the Family

Phylogenetic placement of the family Hydraenidae is currently a matter of disagreement as
certain structures are similar to those of the Hydrophiloidea, whereas others seem to indicate
relationship to primitive families of the Staphylinoidea (especially the Ptiliidae).

Based upon adult antennal form, aquatic habits, and metendosternite, relationships appear
to be with the Hydrophiloidea. The wings, however, are similar to Staphylinoidea, and larvae

Western Hemisphere Hydraenidae

411

markedly resemble those of the Ptiliidae.

This situation provides an example of the difficulties in differentiating similarities due to
plesiotypy or convergence from those due to apotypy (see Hennig, 1966). Proponents of
hydrophiloid relationships for the Hydraenidae suggest that wing and aedeagal structure are
convergent with staphylinoids, a by-product of body size reduction; and larval resemblance is
considered a result of retention of primitive form. Those coleopterists more inclined to place the
hydraenids in the staphylinoid lineage propose that aquatic habits of adults and antennal form
are both a result of convergence with hydrophiloids.

Dybas (1976), in a fine paper on ptiliid and limulodid larvae, has reviewed the literature on
this topic, as has Crowson (1955). I refer the reader to those papers for background
information. Presentation of new data is beyond the scope of this present contribution.

Dybas (1976) has emphasized the “fimbriate galea” in common between larvae of certain
genera in the Ptiliidae (and related staphylinoids) and certain genera in the Hydraenidae. He
considers the fimbriate condition apotypic for these families and states, “Though there has been
lack of agreement as to the systematic position of the family Hydraenidae, I regard it as clearly
belonging in the Staphylinoidea because of the characters of the larva (particularly the maxilla
of Hydraena ) and because of the close resemblance in numerous features of the dorsum of the
abdomen of the adult to that of the generalized ptiliid Nossidium (unpublished data).” He
considers the absence of a fimbriate galea in certain lineages of both ptiliids and hydraenids as
secondary.

On the other hand, Crowson (1955) states that hydraenid “..relationship to the
Hydrophiloids is indicated by the Palpicorn type of antenna and general aquatic adaptations”,
and considers the larval mouthparts “undoubtedly primitive”.

It is evident that phylogenetic relationships of the Hydraenidae remain equivocal, a fertile
area for further research.

Phylogenetic Relationships of the Genera

Little has been written about phylogenetic relationships within Hydraenidae, the few papers
embracing the topic being of a narrative variety. Cladograms have not been published and no
studies have been presented whose specific intent was to distinguish between apotypic and
plesiotypic character states (see Hennig, 1966).

Even the first internal grouping of taxa in the family, resulting in Limnebius on the one
hand and Hydraena-Ochthebius on the other, has been accepted by all previous authors
without rigorous examination. This arrangement results from the different facies of Limnebius
adults, which lack constricted posterior sides on the pronotum seen in adults of Hydraena and
Ochthebius (cf. Figs. 21A,69A,96A). Using only this difference for separating Limnebius , and
likewise uniting Hydraena and Ochthebius , dates at least to Mulsant (1844) in his
“Hydraeniaires” and “Limnebiaires”. The different facies even prompted Thomson (1859) to
place Limnebius in a family “Limnebiidae” and Ochthebius plus Hydraena in the
“Ochtebiidae”.

This first subdivision, and the character upon which it is based, was followed by
d’Orchymont (1916) in his original paper on the phytogeny of the “Palpicornia”
(Hydrophilidae sensu lato ), in which he placed Hydraena plus Ochthebius in the subfamily
Hydraeninae and Limnebius in the subfamily Limnebiinae (and also included Spercheus in the
Hydraenidae). In his catalogue of Indian insects, d’Orchymont (1928) again used this
character. Likewise, Knisch (1924) used this subdivision, and the names Hydraeninae and

Quaest. Ent., 1980, 16 (1,2)

412

Perkins

Limnebiinae. Leech (in Leech and Chandler, 1956) also used the different facies in his key to
the subfamilies, but added the difference in lengths of hind tarsomere 2: longer than 3 in
Limnebius and about as long as 3 in Hydraeninae.

F. Balfour-Browne (1958) presents perhaps the most aberrant view (among recent authors)
considering the first division of the Hydrophilidae (in the broadest sense) to form the
Sphaeridiinae (terrestrial hydrophilids) and all others (including hydraenids) in the
Hydrophilinae (this approach originating, at least in part, from his view that larvae should not
be considered equally with adults when attempting to reconstruct relationships). He,
nevertheless, united Hydraena and Ochthebius (“The Hydraena-Ochthebius Group”) in one
section and presented Limnebius in a separate section, again reflecting the supposed dichotomy.

Although Hydraena and Ochthebius adults are similar to one another in general facies, is
this resemblance due to synapotypy or to plesiotypy? Heads, including the maxillae and head
capsule itself, the pronota, and the metasterna of these two genera differ rather markedly.

In comparison with Hydrophilidae, the elongate body form with pronotum constricted at the
rear is characteristic of Hydrochus and Helophorus adults, two genera commonly accepted (on
the basis of larval structure especially) as retaining more primitive characteristics among the
hydrophilids, whereas the more derived genera of hydrophilids have the body more ovate and
sides evenly rounded as in Limnebius. In fact, it is the resemblance of Limnebius to the higher
hydrophilids that prompted early workers (Erichson, 1837) to place Limnebius in that group.
Many other characters (larval, aedeagal, etc.) reveal that Limnebius rightly is a member of the
hydraenid lineage, and that the superficial resemblance of adults to higher hydrophilids is a
result of convergence (this smooth dorsal habitus is a commonly derived condition,
characteristic of adults of Hydroscaphidae, Ptiliidae, Staphylinidae, Phalacridae, etc.).

Similarity in facies displayed by adults of Hydraena and Ochthebius is therefore very
probably due to inheritance of an ancestral condition (plesiotypy), not synapotypy, and cannot
be used as evidence of relationship.

Consequently, in my study of structure of adults and larvae of the various genera in this
family, I have not assumed a priori that Limnebius represents a lineage separate from the
remainder of the family, and that Hydraena-Ochthebius is necessarily a monophyletic
assemblege. The only two previous publications concerned directly with phylogenetic
relationships within the Hydraenidae, (at the generic level), d’Orchymont (1936A) and
Janssens (1965), omit Limnebius from consideration.

D’Orchymont (1936a) tabulated his conclusions regarding relationships between the various
subgenera of Hydraena. However, he did not distinguish between primitive and derived
character states, other than to note that loss of parameres from Haenydra males was secondary
and monophyletic, whereas reduced number of distinct elytral series of punctures in the same
subgenus was “a rattacher directement a la souche” of Hydraena. (Zwick (1977) has
commented, “ Haenydra is almost certainly not the great evolutionary alternative to Hydraena
(sensu stricto), and the other subgenera,..”, but did not present data to validate his opinion.)

Janssens (1965) is the only author who has attempted to consider phylogeny of the
Hydraenidae on a broader scale, that is, by including a number of the genera (but excluding
Limnebius ). The primary feature which he compared between Ochthebius , Laeliaena,
Hydraenida, Parhydraena and Hydraena was relative lengths of the maxillary palpi, which
become increasingly longer in the sequence as stated. The remainder of his discussion, however,
emphasized the diversity of Ochthebius, and when comparing Ochthebius granulatus with
Hydraena griphus he stated, “Mais peut-on dire que 1’une de ces deux formes soit plus evoluee

Western Hemisphere Hydraenidae

413

que 1’autre? Ou que la genre Ochthebius soit plus (or moins) evolue que la genre Hydraend" .
He did not present a phylogram of the family nor did he discuss common ancestry of the
various genera.

Janssens’ point concerning lengths of the maxillary palpi of the various genera is well taken,
but needs to be pursued in more depth. Ratios formed by dividing length of palpi by length of
antennae (P/A), can be used to construct a morphocline of palpus development. Values for the
ratio for four species in four genera are as follows: Ochthebius tubus , 0.61; Parhydraenida
reichardti, 0.78; Limnebius sinuatus 1.20; and Hydraena circulata , 2.00 (I believe that the
species selected are representative of their respective genera). Based upon this criterion,
Limnebius is between Parhydraenida and Hydraena.

Discovering other features which can be used to form morphoclines is more difficult, since,
as Janssens (1965) has emphasized, the genera are very diverse and divergent one from the
other (especially in the adult stage). There are, however, additional morphoclines which can be
used in phylogeny reconstruction, and also presumed synapotypies for both adults and larvae.
These are discussed below and used in a phylogram (Fig. 147; numbers on phylogram
correspond to those morphoclines and synapotypies listed below). (In the discussion below, the
term “united” is used when two groups share an apotypic character state.)

A. Morphoclines

1. Reduction of gula, and related modifications to the tentorium in adults.

2. Development of closed procoxal cavities in adults.

3. Increasing ratio of maxillary palpus/antenna length in adults.

B. Synapotypies

4. Hydraena-Limnebius united by antennal sensilla of larvae.

5. Hydraena-Limnebius united by form of labral setae in larvae.

6. Hydraena-Limnebius united by form of urogomphi in larvae.

7. Hydraena-Limnebius united by loss of ocelli in adults.

8. Hydraena-Limnebius united by possession of plate-like structure at base
of maxillary palpus in adults.

9. Fimbriate galea in adults of Hydraena lineage.

10. Stoutly spined lacinia in adults of Ochthebius lineage.

1 1 . Non-fimbriate galea in larvae of Ochthebius lineage.

12. Development of pronotal hyaline borders in adults of Ochthebius lineage.

13. Ochthebius-Meropathus-Neochthebius united by form of aedeagus.

14. Neochthebius-Meropathus united by fused elytra, form of metasternum,
body form, and habitat.

15. Hydraenida-Parhydraenida-Coelometopon united by form of head,
number of antennal segments, form of metasternum, and habitat.

16. Hydraena-Spanglerina united by elongate maxillary palpi of adults.

17. Limnebius-Laeliaena united by smooth body form.

Resemblances between genera of different lineages resulting from symplesiotypies and
convergences, such as possession of ocelli, similar body form, aedeagus lacking parameres, etc.,
are discussed below, or have been discussed in previous sections. None of the above data bits
provide conclusive evidence for monophyly or of the branching sequence which I propose,
rather the cumulative effect of these bits of information give credence to the proposed
phylogeny as a whole. Moreover a number of these topics require further research, this
phylogeny being preliminary and subject to revision as new data become available. Differences

Quaest. Ent., 1980, 16 (1,2)

I HYDRAENIDA

rHYDRAENIDINI , PARHYDRAENIDA

15 1 COELOMETOPON

414

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states discussed in text. Rectangle distinguishes taxa of Laurasian origin (inside) from Gondwanian (outside).

Western Hemisphere Hydraenidae

415

Figs. 148 A - D, Head, prosternum, antenna and maxillary palpus. (A) Ochthebius tubus. (B) Parhydraenida reichardti.
(C) Hydraena circulata. (D) Limnebius sinuatus.

Quaest. Ent., 1980, 16 (1,2)

416

Perkins

Figs. 149A - F, Head, ventral aspect. (A) Ochthebius tubus \ (B) Gymnochthebius clandestinus. { C) O. tubus. (D)
Limnebius sinuatus. (E-F) Parhydraenida reichardti.

Western Hemisphere Hydraenidae

417

between closely related genera are discussed elsewhere in the text and summarized in the key to
genera.

1. Reduction of gula, and related modifications to the tentorium of adults. - The genera
Ochthebius , Meropathus,Neochthebius, Gymnochthebius and Tympanogaster (Australian)
have a large, triangular gula with a relatively short median gular suture (Fig. 148 A), whereas
in Hydraena, Hydraenida, Parhydraenida and Coelometopon (African) the gula is much
smaller, apparent as a narrow transverse sclerite at the rear of the head, and the median gular
suture is longer than in the Ochthebius group (Figs. 148B,C). The morphocline is completed in
Limnebius, which lacks both gular sclerite and median gular suture (although there may be a
weak impression in adults of some species), but retains remnants of the lateral gular sutures
(Fig. 148D).

To see these features in their entirety the head must be cleared of tissue with hydroxide
solution and the pigment partially removed with hydrogen peroxide. When an untreated
specimen is viewed with reflected light, the gular sclerite of Ochthebius and allied genera is
readily apparent (Figs. 103C,128C,145B,152A,B), whereas in Hydraena , Hydraenida and
Parhydraenida the transverse gular sutures may be evident in lightly colored species, but the
most prominent external manifestations are the invaginations (apodemes) marking the lateral
limits of the sclerite (Figs. 21H,57A,63G,65D,149E). In Limnebius there is only the slightest
indication of the lateral gular sutures, and these are generally hidden beneath the anterior edge
of the prosternum in dried specimens (Figs. 152C,D).

These differences in the gular sclerite are related to rather marked differences in form of the
tentorium. The tentorium of Ochthebius and allied genera ( Gymnochthebius , Meropathus,
Neochthebius ) (Figs. 151A,B,D) forms a complete enclosure around the subesophageal
ganglion. The anterior “wall” of the tentorium provides the muscle attachment site for some of
the muscles which move the mouthparts. In the center of the “wall” is a small foramen through
which nerves pass connecting the ganglion and the anterior part of the head. The larger
foramen through which nerves pass connecting the brain and subesophageal ganglion is divided
by a narrow portion of the tentorium.

In Hydraena and Parhydraenida the tentorium (Figs. 150D,151C) lacks the complete
anterior “wall”, this structure being reduced to a low transverse ridge (arising from the
transverse gular suture) near the rear of the head. Some of the muscles which move the
mouthparts are attached to this ridge, and are, therefore, longer than the homologous muscles
in the head of an Ochthebius (etc.) of comparable size. Since these muscles attach closer to the
rear of the head, a major portion of the subesophageal ganglion is on top of the muscle fibers, in
contrast to Ochthebius (etc.) where the anterior “wall” of the tentorium completely separates
the muscles and the ganglion. Further, the foramen through which nerves pass connecting the
brain and subesophageal ganglion is a single opening, not divided as in the Ochthebius group.

The structure in Limnebius (Figs. 150A-C) is very similar to the Hydraena-Parhydraenida
type, except that the anterior “wall” of the tentorium is now contiguous with the posterior
margin of the head, which, again, provides the site for muscle attachment. Therefore, the
muscles completely separate the subesophageal ganglion from the ventral part of the head
capsule. The remainder of the tentorium is very similar to that of the
Hydraena-Parhydraenida type.

Differences in lengths and to a certain degree mass of muscles (more mass in Ochthebius)
between these three types, and especially between Ochthebius ( et cetera) and the others taken
together is interesting. Perhaps it relates to form of maxillae, which are much stouter and of the

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Figs. 150A - D, Tentorium (arrows indicate opening through which nerves pass between brain and subesophageal
ganglion). (A-C) Limnebius sinuatus. (D) Hydraena atlantica (some distortion due to hydroxide treatment).

scraping, rasping type in the Ochthebius group (Fig. 98F), but more of the gathering type in
the other genera (Figs. 153A-H). Then again, if a certain muscle length were necessary to
function properly, having the attachment at the rear of the head would allow the head to
become shortened, as in Limnebius.

That a morphocline is indicated should be evident from the above discussion, but what is the
direction of change? Based on out-group comparisons, (see Maslin, 1952; Hennig, 1966),
direction of this morphocline must be from the more developed gular sclerite and tentorium to
the less developed (i.e., reduction) since both the Hydrophilidae and Staphylinidae have a well
developed gular sclerite in adults.

2. Development of closed procoxal cavities in adults. — The procoxal cavities vary
considerably within the family, differences occurring in degree of development of the (1) coxal
cavity base, (2) intercoxal process, and (3) proepisternum. The coxal cavity base exhibits a

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419

Figs. 151 A - D, Tentorium (horizontal arrows indicate foramen in wall separating subesophageal ganglion and muscles of
mouthparts; vertical arrows indicate opening through which nerves pass between brain and subesophageal ganglion).
(A-B) Meropathus vectis. (C) Parhydraenida reichardti. (D) Ochthebius puncticollis.

morphocline in increasing development from Ochthebius and allied genera ( Meropathus ,
Neochthebius ) through Limnebius, to Hydraena (Figs. 54I,148A-D,152A-F). By out-group
comparison, the open condition must be considered primitive, as the coxal cavities are open in
the great majority of Hydrophilidae and Staphylinidae. Consequently, direction of the
morphocline is presumably toward increased development of the cup-shaped coxal cavity,
which again indicates affinities between Hydraena and Limnebius. The intercoxal process is
well developed in Hydraena and Spanglerina (Figs. 2 IE, 541, 65D), whereas the proepisternum
is markedly reduced in Limnebius , both of which I consider derived conditions for these
structures.

3. Increased values for ratio of maxillary palpus/antenna length in adults. — As discussed
earlier, this ratio (P/A) increases from Ochthebius to Hydraena in this representative
sequence: Ochthebius tubus , 0.61; Parhydraenida reichardti , 0.78; Limnebius sinuatus , 1.20;

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Figs. 152A - F, Prosterna (left leg removed). (A) Ochthebius tubus. (B) Gymnochthebius clandestinus. (C-D) Limnebius
sinuatus. (E-F) Parhydraenida reichardti.

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421

Figs. 153A - H, Adult maxillae. (A-C) Hydraena atlantica (arrow indicates “plate” protecting base of palpus). (D-E)
Parhydraenida reichardti. (F-G) Limnebius sinuatus (arrow indicates “plate” protecting base of palpus). (H) Hydraena
anisonycha.

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Figs. 154A - C, Larval labrum. (A) Ochthebius tubus. (B) Hydraena circulata. (C) Limnebius alutaceus.

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Figs. 155A - B, Hydraena circulata, larval antenna. (A) dorsal aspect. (B) ventral aspect.

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Figs. 156A - B, Limnebius alutaceus, larval antenna. (A) dorsal aspect. (B) ventral aspect

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Figs. 157A - B, Ochthebius tubus , larval antenna. (A) dorsal aspect. (B) ventral aspect.

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Figs. 1 58 A - B, Apical abdominal segments of larvae. (A) Hydraena circulata. (B) Ochthebius gruwelli.

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427

Hydraena circulata, 2.00 (Figs. 148A-D). By generalized out-group comparison the plesiotypic
state is antenna much longer than maxillary palpus. Thus direction of this morphocline should
be toward an increase in value of the ratio (i.e., in the sequence as stated above). The branching
sequence suggested by this morphocline, therefore, concurs with that suggested by the two
previous morphoclines.

4. Hydraena-Limnebius united by antennal sensilla of larvae. — The antennae of Hydraena
and Limnebius larvae (Figs. 155,156) (here represented by Hydraena circulata and Limnebius
arenicolus) have a dorsal and a ventral sensillum, whereas the antennae of Ochthebius
(Fig. 157) (represented by Ochthebius tubus) possess only the ventral sensillum. Richmond
(1920) illustrated the antenna of Hydraena pennsylvanica with a single sensillum, but two are
present (I have used phase-contrast microscopy at a magnification of lOOOx). I have also
studied other species of Ochthebius (these findings and others on hydraenid larvae will be
presented in a separate paper devoted solely to larvae) and have found the single sensillum a
constant feature in that genus.

By out-group comparison the single sensillum must be considered primitive, as all
Hydrophilidae (Richmond 1920, and unpublished data) and Staphylinidae ( sensu lato)
(Paulian, 1941) have a single sensillum. Consequently, two sensilla is the derived condition, and
from which can be inferred monophyly of Hydraena and Limnebius. Further, shape of the seta
adjacent to the ventral sensillum in Hydraena and Limnebius is also suggestive of a
relationship.

Dybas (1976) in his excellent paper on larvae of Ptiliidae and Limulodidae has shown that
the antenna of the ptiliid Nossidium also has two sensilla whereas the remainder of the ptiliids
and limulodids he studied had a single sensillum or a single one which is bifid ( Actidium ). This
raises questions concerning which condition is the primitive state since Dybas considers
Nossidium as the ptiliid genus retaining the most primitive characteristics.

Dybas (1976:41), however, also illustrates the antenna of an undescribed genus near
Nossidium which lacks the second sensory appendage (“accessory sensory appendage” of
Dybas). This undescribed genus is also remarkable in that, according to Dybas, it is the only
known ptiliid larva with indications of ocelli or pigmented eyespots, which Dybas considers
plesiotypic, “The retention of eye pigment in a member of the most generalized group of
Ptiliidae represents a plesiomorphic or ancestral character that has been lost in the other genera
studied.” That the plesiotypic condition of the ocelli has been retained in this larva certainly
does not mean that the antennae necessarily also represent the primitive condition with respect
to sensilla, but it does make one suspicious that the two sensilla condition of Nossidium may
actually be a derived condition, whereas the single sensillum of the remainder of the genera is
plesiotypic.

5. Hydraena-Limnebius united by form of labral setae in larvae. — The labrum of
hydraenid larvae has five pairs of setae along the anterior margin, the second pair from the
midline being thickened and branched. In Ochthebius these setae (Fig. 154A) bifurcate,
whereas in Hydraena and Limnebius (Figs. 154B,C) the setae are pectinate.

D’Orchymont (1928:8) stated that in the Hydraeninae ( Hydraena and Ochthebius ) the
“first anterior seta of labrum (on each side) curved to the axis of body and ramous at extremity
or at least bifid”, whereas in the Limnebiinae ( Limnebius ), the “first anterior seta covered also
to the body but single, not even bifid at extremity.” In the few larvae I have studied the
complex setae are the second pair and these are not simple in Limnebius , and suspect higher
magnification accounts for differences in our findings.

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Fig. 1 59. Limnebius arenicolus, apical abdominal segments of larva.

Since I have no means at present for testing whether the pectinate or bifurcate condition
represents the apotypic state, the supposed relationship of Hydraena and Limnebius based upon
common possession of the pectinate condition must be considered untested and subjective.
Discovery of the larval stage of Hydraenida, Parhydraenida and other rare genera is necessary
to establish morphoclines.

6. Hydraena-Limnebius united by form of urogomphi in larvae. — The urogomphi of
Hydraena and Limnebius larvae (Figs. 158A,159) have a seta which originates at the apex of
the basal article. Ochthebius (Fig. 158B), on the other hand, has this seta originating farther
proximally. Moreover, form of the urogomphi in Hydraena and Limnebius are more similar to
one another than either is to Ochthebius. Finally, distance separating the urogomphi at their
bases, a character often used in keys (Richmond, 1920; d’Orchymont, 1928; Chandler, in Leech

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429

and Chandler, 1956), is equal to or greater than the width of a urogomphus at its base in
Hydraena and Limnebius, whereas in Ochthebius the urogomphi are nearly contiguous
proximally.

Unfortunately, not enough data are available on urogomphus chaetotaxy or form in the
primitive staphyliniform larvae to establish the primitive state, these proposed synapotypies
being therefore untestable at this time. Judging from illustrations by Dybas (1976), less derived
larvae of Staphylinoidea (i.e., Ptiliidae and Limulodidae) generally have the urogomphi
situated dorsally and rather close together. From this one might suspect the ancestral condition
of the Staphyliniformia (and the Hydraenidae) to be likewise. Therefore, the more widely
separated urogomphi of Hydraena and Limnebius could be considered synapotypic. Various
degrees of urogomphus separation is seen in the more derived Staphylinoidea (Paulian, 1941)
and the Hydrophilidae have the apex of the abdomen (in the more derived genera) highly
modified to form a stigmatic atrium, whereas the less derived genera (with respect to
urogomphi) have the urogomphi moderately separated ( Helophorus ; Richmond, 1920) or
widely separated ( Epimetopus; Rocha, 1967).

7. Hydraena-Limnebius united by loss of ocelli from adults. — If ocelli in the adults of
Coleoptera represents retention of a primitive condition, then absence of ocelli in Hydraena and
Limnebius could be considered synapotypic and therefore indicative of monophyly. Conversely,
common possession of ocelli by Ochthebius (plus allied genera) and Hydraenida (plus allied
genera) cannot be used as indicative of relationships as such a grouping would be based upon
symplesiotypy.

8. Hydraena-Limnebius united by possession of plate-like structure at base of maxillary
palpus in adults. — The maxillae of Hydraena and Limnebius adults have a thin, plate-like
structure arising from the stipes, at the base of the maxillary palpus (Figs. 153C,F). This
structure, which presumably adds support to the base of the maxillary palpus, is absent from all
other genera studied ( Parhydraenida , Ochthebius, Meropathus and Neochthebius (but present
in Spanglerina also). It is presumed that this plate is a derived structure, and therefore
indicates monophyly of Hydraena and Limnebius.

9. Fimbriate galea in adults of Hydraena lineage.

10. Stoutly spined lacinia in adults of Ochthebius lineage. — Galeae of Hydraena,
Limnebius and Parhydraenida adults (Figs. 153A-H) are quite similar, having a well
developed, fimbriate apex which is larger and more prominent than the lacinia, and
undoubtedly accomplishes most of the gathering of food particles. By contrast, the galea of
Ochthebius, Meropathus and Neochthebius (Fig. 98F) is much less complex and does not
extend beyond the lacinia, the latter possessing stout scraping processes which obviously
perform most of the actual food gathering function of the maxillae.

That two basic types are involved is clearly evident, but which represents the derived state? I
propose that the more complex stage of both structures, that is, the complex fimbriate galea of
Hydraena-Limnebius-Parhydraenida and the stoutly spined lacinia of
Ochthebius-Meropathus-Neochthebius represent the derived states, the plesiotypic condition
being simplified in both structures. Development of the lacinia in one lineage and galea in the
other must surely reflect differences in feeding habits, but what these differences may be
remain undiscovered. Out-group comparisons, especially in other less derived staphyliniform
beetles, are necessary to test these assertions.

11. Non-fimbriate galea in larvae of Ochthebius lineage. — Dybas (1976) has shown that
larvae of Hydraena possess a fimbriate galea and that this structure is common to most genera

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in the “leptinid association” of Boving and Craighead (1931). Larvae of Limnebius also have a
fimbriate galea. However, larvae of Ochthebius (Richmond, 1920; unpublished data),
Meropathus (Paulian, 1941) and Neochthebius (unpublished data) lack fringed margins on the
galea. If the fimbriate condition is primitive (according to Dybas this would be the primitive
state within the “leptinid association”, but derived with respect to the Staphylinoidea), then the
non-fimbriate condition of Ochthebius and related genera can be considered synapotypic.

12. Development of pronotal hyaline borders in adults of the Ochthebius lineage. — One of
the most distinctive developments of the Ochthebius lineage is hyaline borders of the pronotum.
These are present at the anterior and posterior margins ( Meropathus , Neochthebius ) and
generally laterally also ( Ochthebius , Gymnochthebius ) (Figs. 80A-F,98A, 145A,C). These
transparent borders are probably apotypic as they are lacking from the remainder of the family
and also unknown in the Hydrophilidae and (to my knowledge) the remainder of the
Staphyliniformia.

13. Ochthebius-Meropathus-Neochthebius united by form of the aedeagus. — As discussed
in the section on Gymnochthebius , the basic plan of the aedeagus in that genus differs from
that of other genera of that lineage, i.e., Ochthebius , Meropathus and Neochthebius , and
apparently represents a different evolutionary line. Further, it is proposed that the bilaterally
symmetrical “median piece” of the aedeagus in the less derived species of Gymnochthebius (G.
plesiotypus. Fig. 82A) more closely approximates the ancestral form of the lineage, and,
therefore, the aedeagal type of Ochthebius-Meropathus-Neochthebius which possesses a
terminal mobile piece (and lacks the internal tube seen in Gymnochthebius) represents a
derived state.

14. Neochthebius-Meropathus united by fused elytra, body form, metasternal shape, and
habitat. — As discussed in the sections on Neochthebius and Meropathus, the above similarities
suggest monophyly of these two genera. No doubt the character states are apotypic.

15. Hydraenida-Parhydraenida-Coelometopon united by form of head, number of
antennomeres , form of metasternum, and habitat. — Similarity of Hydraenida and
Parhydraenida adults in external features are apparent (refer to the section of Parhydraenida).
They share with Coelometopon , a very highly derived madicolous genus from east Africa, 1 1
antennomeres which are in well developed grooves beneath the eyes (Fig. 16A). Additionally,
the metasternum of these three genera has a longitudinal impression in the midline and the
maxillary palpi are of similar proportions.

16. Hydraena-Spanglerina united by elongate maxillary palpi of adults.— No doubt the
elongate maxillary palpi of these two genera (Fig. 148D) represent an apotypic character state.

17. Limnebius-Laeliaena united by smooth body form. — The reduced body form of adults
of these two genera is readily apparent and derived. Laeliaena, a rare genus from Turkestan (1
species) and India (1 species), retains the incised posterior angles of the pronotum (a primitive
condition) but is very similar to Limnebius in other characters. (Note: my concept of Laeliaena
is based on specimens of Laeliaena sahlbergi Champion in the BMNH; I have not seen adults
representing the type of the genus, Laeliaena sparsa Sahlberg).

Two primary evolutionary lines are inferred from morphological data (see phylogram,
Fig. 147); Ochthebius plus related genera, and the Hydraenida-Hydraena-Limnebius lineage.
Consequently, I propose that the Ochthebius group be recognized as a new subfamily, the
Ochthebiinae, and that the Limnebiinae (of authors) be ranked as a subtribe within the
Hydraeninae. Further, to reflect differences in the two major lineages within the Hydraeninae,
I propose that they be recognized as tribes, the Hydraenini and Hydraenidini. Within the

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431

Hydraenini two new subtribes are proposed, Hydraenina and Limnebiina.

Zoogeography at the Generic Level

The nine genera of Hydraenidae now recognized in the Western Hemisphere display rather
distinct Gondwanian or Laurasian distribution patterns, indicating that most, if not all of the
genera evolved before North and South America separated from their respective
supercontinents. To the contrary, however, several species groups within the genera appear to
be endemic to the Western Hemisphere and therefore possibly originating after splitting of the
continents.

The Gondwanian components include Gymnochthebius, Hydraenida, Pahydraenida,
Meropathus and the leechi and marginicollis Groups of Hydraena , whereas the genera
Ochthebius (including both subgenera) and Limnebius, and apparently also the circulata
Group of Hydraena , are of Laurasian origin (Figs. 160,161). Spanglerina might be endemic to
Central America, but I would not be greatly surprised if it is eventually found in Africa.

Genus Gymnochthebius

Gymnochthebius has a wide distribution in South and Central America, with few species in
North America (Fig. 161). It is also represented in Australia (d’Orchymont, 1943; Janssens,
1967a), but is apparently absent from Africa. This distribution pattern is consistent with
current hypotheses regarding separation sequence of Africa, South America, Australia and
New Zealand (Keast, 1973), in which Africa is postulated as the first component to have
separated from the Gondwana landmass.

As discussed more fully in the classification section, the less derived lineages (i.e.,
plesiotypus lineage) are in southern South America (Chile and Argentina), whereas the more
derived lineages ( laevipennis and oppositus lineages) are North American. Absence of these
derived groups from the Palearctic indicates that these lineages possibly evolved after
continental splitting (see later sections on these groups for phylogenetic relationships). The
nitidus Subgroup might also be in this category, but the wide distribution of one of its species
(G. fossatus) in South America invites the suspicion that the Subgroup might also be in
Australia (the Australian fauna is too incompletely known to confidently use absence of a
lineage as evidence for post-split evolution).

Genus Hydraenida

Hydraenida and the closely related Parhydraenida are currently known only from South
America (Fig. 160). However, I have seen an undescribed species of Hydraenida from South
Africa and suspect that Parhydraenida will eventually be found there also. These data appear
to contradict what was stated previously regarding earlier separation of Africa, but absence of
these two genera from Australia may only be apparent. If distribution of Hydraenida is correct,
then one must surmise that the genus was present in the South American and African, but not
Australian, components of Gondwana before continental split.

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Fig. 160. Generalized geographical distributions of hydraenid genera Hydraenida , Parhydraenida , Hydraena, Spanglerina
and Limnebius in the Western Hemisphere.

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Fig. 161. Generalized geographical distributions of hydraenid genera Gymnochthebius , Ochthebius, Neochthebius and
Meropathus in the Western Hemisphere.

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Genus Parhydraenida

Parhydraenida is restricted almost entirely to the mountains of southeastern Brazil, with
one widely disjunct species, P. pentatenkta, in Ecuador (also an undescribed species in
Paraguay). This disjunct distribution may be simply a result of insufficient collecting in
intervening areas.

Based upon label data, Parhydraenida is clearly hygropetric, as is the related Coelometopon
from Tanzania (see Janssens, 1972b). Hydraenida apparently is not strictly hygropetric, as
Paul Spangler has collected H. robusta from small pools at a roadside seepage area of loess
substratum.

Genus Meropathus

Meropathus has a typical austral Gondwanian distribution pattern, living on islands of the
New Zealand subregion (3 species), the island group consisting of Prince Edward Islands,
Kerguelen Island and Heard Island (1 species), eastern Australia (3 species), and Isla de los
Estados and Falkland Islands at the tip of South America (1 species), the latter discovery
completing the circum-polar distribution pattern.

As Ordish (1971) has noted, the early supposition that Meropathus was endemic to the
subantarctic islands was dispelled by discovery of Australian species, and suggests that their
present distribution may be a result of continental drift. Since insular species are frequently
taken from nests of large oceanic birds, together with the fact that these beetles have relatively
long, stiff bristles on the dorsal surface which collect debris, possibly these beetles could adhere
to feathers of birds and thus be dispersed to other islands.

But if one proposes that individuals of the vectis-campbellensis stem species were brought
by birds from Campbell Island to South America (ca. 4,800 miles), does not this suggest that
transport of these beetles over short distances must be a much more common occurence? If this
be so, then one would suspect transport between Campbell Island, Auckland Islands and Snare
Islands (ca. 200 miles between each) is frequent enough to result in dispersal, not speciation.
This clearly is not so; each island group has a different species (see Ordish, 1971), and no two
species are found on one island. Distribution of the Australian species must be explained by
methods other than avian transport as they are associated with streamside habitats, not nests of
large oceanic birds.

Genus Hydraena

Hydraena (Fig. 160) includes four groups, two of which ( leechi and marginicollis Groups)
are widespread and principally tropical, which have invaded North America via the Mississippi
River drainage system and the eastern coastal regions. These two groups, as now known, do not
extend into the more temperate areas of southern Argentina and Chile (this may be a collecting
artifact with regard to Argentina, but the large number of Gymnochthebius specimens I have
seen from Chile suggests that appropriate collecting has been done in that region, although no
Hydraena has been found). Another component ( circulata Group) is strictly North American,

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435

forming small areas of sympatry with the tropical groups in southern Arizona, the Mississippi
drainage, and in northeastern United States. The last of the four components (paeminosa
Group) is known only from a single species in Surinam.

I have seen specimens of Hydraena from the Palearctic, Ethiopian and Australian regions
which appear to be members of the leechi Group, and also suspect that the marginicollis Group
was rather widespread on Gondwana and, to a less extent, Laurasia, before the New World
diverged. Within these two lineages, however, are several sublineages with apotypic states not
yet described in Old World forms (i.e., scintilla of the pronotum) suggesting that at least the
leechi, alternata and scintillabella Subgroups of the leechi Group evolved after continental
separation. I also suspect that the more highly derived sublineages within the marginicollis
Group (i.e. anisonycha Complex of the marginicollis Subgroup and the geminya Subgroup)
evolved following continental splitting. The amount of taxonomic work remaining to be done on
Old World members of this large and complex genus, especially in tropical areas, prevents a
definitive statement at this time.

The paeminosa Group, with its single species in Surinam, has important external
characteristics in common with the Nearctic circulata Group, but has a much different (more
highly derived) aedeagus in which the parameres are reduced to small processes near the apex
(Fig. 95D)(a condition convergent with Parhydraenida). It may be a remnant of the North
African component of the principally Laurasian paeminosa-circulata stem group.

Minimum age of Hydraena in North America can be inferred from fossil fragments of the
extant species, H. angulicollis from Pleistocene deposits of Scarborough Bluffs, near Toronto,
Ontario. These fragments are reputedly 70,000 years old (see Morgan, 1971)(see comments
below concerning Ochthebius fossils).

Genus Ochthebius

Ochthebius is clearly of Laurasian origin, both subgenera in the Western Hemisphere being
well represented in the Palearctic. In fact, at least two of the four sublineages ( interruptus and
benefossus Groups) have Palearctic components. The other two sublineages ( bisinuatus and
biincisus Groups) apparently have evolved after continental separation (or were present before
the split but only in the pre-North American component).

The great concentration of different lineages and species in western North America as
opposed to the two species (O. benefossus and O. putnamensis ) in eastern North America (see
Figs. 180-185) might be cited as evidence in support of the “Pacifica” theory in which land
components of western North America are theorized to be of a western Pacific (eastern
Palearctic) origin.

This western North American distribution might also be credited to Pleistocene dispersal of
stem species across the Bering land bridge (see Darlington, 1957). The holarctic distribution of
O. kaszabi and O. marinus, plus the usual habitat of those species, boreal ponds, suggests such
a dispersal. The majority of other species in the genus in western North America, however, are
montane stream forms, a habitat not generally associated with the land bridge. A possible
scenario is that a stem species of all Ochthebius ( sensu stricto)) in the New World (or several
stem species, each the ancestor of its respective sublineage of Ochthebius (sensu stricto ))
crossed the land bridge, diverged and proliferated to form the Ochthebius seen today, two
species of which, O. kaszabi and O. marinus, later recrossing into the Palearctic.

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However, through the courtesy of Dr. Anne Morgan I have seen a fossil pronotum which is
either O. kaszabi or O. marinus (it is impossible to be totally certain because of morphological
overlap of pronotal characters in present day specimens). This beetle fragment is from
Pleistocene deposits near Toronto, Ontario which are dated at about 100,000 years of age
(Morgan, in litt.). We know, therefore, that O. kaszabi or O. marinus had already evolved
before the Pleistocene (if one assumes that its presence in both the Nearctic and Palearctic is
due to crossing the land bridge, then it must have been present before emergence of the bridge;
of course, this is true also if the present distribution is due to a Laurasian pattern).

The aedeagus of O. kaszabi is strikingly different from aedeagi of New World species with
which it is most closely related (i.e., O. marinus, O. borealis and O. uniformis
-Figs. 108A-D,1 10A-D). This prompts the inference that its presence in the New World is due
to relatively recent (Pleistocene) dispersal across the Bering land bridge. Its sister-species,
therefore, possibly exists in the Palearctic, and is not one of the Nearactic members of its
lineage. In fact, the Palearctic and Nearctic populations of O. kaszabi at present are
genetically and morphologically diverging due, in part, to range disjunction of the ancestral
stock, caused by the Bering Sea.

Fossil fragments (pronotum and elytra) of O. (Asiobates) discretus from the Pleistocene
Scarborough Bluffs deposits near Toronto, Ontario, which are 70,000 years old (see Morgan,
1971) leads to the inference that the subgenus Asiobates was probably also present in North
America before Pleistocene glaciation.

Genus Limnebius

Limnebius occupies, in North America, three slightly disjunct areas (Fig. 160), the Great
Basin and Central Prairies lacking proper habitats for this genus. It extends southward as far as
Guatemala, but is unknown from the remainder of Central America, the Antilles and South
America. The genus is best represented in north temperate areas, apparently being Laurasian
in origin as it is absent from South America and Australia. Its presence in Africa, therefore, is
probably a product of range expansion after South America and Africa separated. Its presence
in North America is probably a result of Laurasian distribution, not recent dispersal.

Genus Neochthebius

The genus Neochthebius is currently known only from two closely related intertidal species,
N. granulosus from Japan and N. vandykei of the North American Pacific coast (Fig. 161).
Neochthebius is apparently the sister-group (see previous section on phylogeny) and Laurasian
counterpart of the Gondwanian Meropathus. The distribution of Neochthebius in Japan and
western North America (instead of South America or Africa) suggests that the stock from
which the two genera are derived probably was present at the “Australian end” of Pangaea.
The presence of N. vandykei on the opposite side of the Pacific Ocean from Japan may be
explained by dispersal in sea currents along the coast (they are wingless) in Pleistocene times
(and subsequent vicariance), or by referral to a “Pacifica” land movement model.

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437

Zoogeography and Phytogeny within the Genera

Vicariance and Chance Survivors Models. — The number of new taxa described herein is an
indirect indication of the work remaining to be done in other regions of the world, especially
Africa and Australia; considerations of historical zoogeography and phylogeny of the family
should be tempered by this reality. Even within South America I suspect knowledge of the
hydraenid fauna is quite incomplete, at least in respect to species diversity within
Gymnochthebius and, especially, Hydraena.

My level of confidence is high, however, that distributional limits now known for Limnebius
(not found south of Guatemala) and Ochthebius (southern limits in northern South America
for stream species - halophilic species such as O. attritus extending farther southward along the
coasts) approximate the real limits (Figs. 160,161).

Even within Central America and the Caribbean Islands knowledge of the hydraenid fauna
is incomplete, at least for Hydraena. The groups of species now known, based primarily upon
aedeagal structure, such as the particeps Subgroup and the mexicana and marginicollis
Complexes (see below), suggest that our knowledge of Hydraena in that region is sufficiently
complete to permit a reasonable evaluation of the relationships of structural evolution and
historical zoogeography.

The North American fauna is the most completely known, which distinctly enhances
discussion of species of that region which have affinities with primarily tropical components of
the hydraenid fauna.

At the time of this writing there has been, within the pages of the journal Systematic
Zoology , much discussion and disagreement concerning two theories which attempt to explain
patterns of plant and animal distribution: 1) center of origin and dispersal, and 2) vicariance.

Croizat, Nelson and Rosen (1974) summarize the differences between these two theories
and I refer the reader to that paper and its bibliography for anterior works related to the topic.
Briefly, both theories accept dispersal of organisms and that genetic isolation of a populational
(species) subunit is necessary for speciation to occur. They differ in their suppositions regarding
temporal relationship of dispersal and barrier formation.

Because both theories accept occurrence of dispersal, it is inappropriate to refer to one
theory as “center of origin and dispersal” (and to its advocates as “dispersalists”). I propose to
designate this theory as that of “chance survival” for reasons presented below.

Proponents of vicariance reject the idea that the primary driving force in speciation is
chance dispersal of a few individuals across a nearly perfect, pre-existing barrier^ my emphasis)
(topographic, ecologic, etc.), and the supposed isolation that follows which would provide the
time necessary for genetic divergence and eventually speciation. Instead, vicariance advocates
propose that barriers arise within distributional limits of a species, dividing it into two or more
isolated populations which then undergo genetic divergence, eventually to the level of species
(see Platnick, 1976).

Since advocates of vicariance acknowledge dispersal, they must accept that crossing nearly
perfect, pre-existing barriers does occur, but their denial of this process as a major cause of
speciation presupposes that the rate of genetic divergence between the two populations thus
formed is slow enough that subsequent, and repeated crossings of the nearly perfect,
pre-existing barrier will occur before, and prevent, speciation; and/or that occurrence of nearly
perfect pre-existing barriers is rare in nature.

It appears that a perfect balance of three factors must be reached for speciation to occur
when “chance survivors” cross a pre-existing barrier. First, rate of genetic change must be

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adequate to allow speciation to take place before the next “chance survivors” arrive (if
individuals cross a static barrier once, logic dictates that, given enough time, other individuals
will also cross).

Second, balance between vagility of species and effectiveness of the barrier must be within
very narrow limits. By way of example, if a stream-dwelling hydraenid species is expanding its
range and encounters an arid, streamless barrier, for the “chance survivors” theory to operate,
vagility of the species and size of the arid barrier must be perfectly matched. If the barrier is
too extensive for the vagility of that particular species, no crossing will be achieved; conversely,
if vagility is too great for that particular barrier, too many crossings will be accomplished and
consequently range expansion will occur and not speciation.

Further, the slower the rate of genetic divergence, the greater the length of time necessary
for speciation of two reproductively isolated populations; hence, the slower this rate the more
“perfect” must be the match between vagility and the barrier.

Therefore, advocates of the importance of chance survival postulate perfect balance between
these three components: 1) dispersal capabilities (vagility), 2) barrier completeness, and 3)
genetic divergence.

By contrast, advocates of the importance of vicariance postulate that 1) totally effective
barriers arise within the distributional limits of a species, and 2) duration of a barrier is
adequate to permit genetic divergence necessary for speciation. A perfect “mix” of the
vagility-barrier-genetic divergence components of speciation is not necessary for the vicariance
model. Based upon the great number of extant and extinct species, the vicariance model must
also postulate occurrence of numerous range interruptions to account for the great diversity of
plants and animals. (Existence of numerous barriers is also implied in the chance survivors
model; in fact, many more than the vicariance model since only a small percentage of those
barriers would be sufficiently perfect to permit speciation). This supposition certainly is not
inconsistent with our current knowledge of plate tectonics, continental drift, orogeny, climatic
shifts, etc..

Because of 1) the narrow constraints imposed by the chance survivors model, 2) knowledge
of continental drift and other events that lead to vicariance, and 3) relatively slow genetic
divergence (as opposed to dipersal capabilities of winged insects) indicated by age of fossil
beetle fragments of extant species (see Coope 1967; Coope and Brophy, 1972; Ashworth and
Brophy, 1972; Ashworth 1973a,b; Morgan 1972), I find the vicariance model the more logically
attractive of the two concepts, and therefore interpret distribution data with vicariance in mind
(although not disregarding the chance survivors model).

Genus Hydraenida

Marked dissimilarity in male genitalia (Figs. 13A,B) suggests that the two included species
diverged from a common ancestor a long time ago.

Genus Parhydraenida

The provisional phylogeny (Fig. 162) is based upon the following postulated synapotypies
(numbers refer to those given in phylogram): 1) hydrofuge pubescence of abdominal sterna 1-4

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439

plus anterior portion of 5; 2) hydrofuge pubescence on abdominal sterna 1-2 plus anterior
portion of 3; 3) aedeagus with well developed dorsal lobe (e.g., largest lobe in reichardti ,
Fig. 18A); 4) reduced pronotal sculpture; 5) aedeagus with a lobe between flagellum and
median piece (Fig. 18B); 6) clypeus quadrate, aedeagus with dorsal lobe partially or wholly
coalesced (Figs. 1 8C, 1 9); 7) right paramere reduced to spike situated at apex of median piece;
8) aedeagus with short left paramere.

Fig. 162. Generalized geographical distributions and proposed phylogeny of Parhydraenida species in southeastern Brazil
( P . pentatenkta , an Ecuadorian species, is omitted).

Validity of this proposed phylogeny will be tested when the male of P. pentatenkta is
discovered and its aedeagus characterized. Further, I have seen a number of females from
southeastern Brazil which apparently represent additional undescribed species. Once the males
of these species are described and their aedeagi characterized, relationships suggested herein
can be further tested and the reconstructed phylogeny modified accordingly.

Comparison of the phylogeny and distribution patterns suggests a vicariant event between
current distributions of P. bubrunipes and P. quadraticeps. This event could have concurrently
split the stem species of those two species and also provided the first dichotomy in the other
major lineage (i.e., P. effeminata to the south, and its sister-group to the north). The
distributions at first glance appear sympatric, but this is due to the rather widely distributed P.
reichardti. Actually, no proposed sister-species pairs display sympatry. Whether this reflects
actual distributions or is an indication of inadequate sampling remains to be seen.

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Genus Hydraena

The species of Hydraena in the Western Hemisphere are arrayed in four major lineages.
The proposed phylogenetic relationships of these four lineages are based upon complex
aedeagal structure and development of a pronotal scintilla in the leechi and marginicollis
Groups (Fig. 163A:1) and the development of a genal ridge and concave intercoxal sternite in
the circulata and paeminosa Groups (2). Plesiotypic states of these characters include: a simple
aedeagus, lack of a pronotal scintilla, lack of a genal ridge, and a flat intercoxal sternite. This
provisional phylogeny will be verified or modified as the phylogeny of non-Western Hemisphere
species of Hydraena are elucidated. At present, I suspect that each of these four groups were
well defined before continental drift, as a preliminary study of species from the Ethiopian and
Australian regions indicates close similarity with members of the leechi and marginicollis
Groups.

Adults of the circulata Group share marked similarities in habitus and aedeagal details
which are taken as evidence for monophyly. The pronotum of H. paeminosa , the only species
now known for the paeminosa Group, bears a resemblance to that of the circulata Group;
likewise, the intercoxal sternite is shaped similarly in both Groups. H. paeminosa differs in that
the elytral punctures are totally random, not in series as in circulata Group species.
Additionally, aedeagi of H. paeminosa males differ in basic plan from those of males of the
circulata Group, having the parameres very reduced, originating near the apex of the aedeagus.
H. paeminosa is a South American species; all circulata Group species are Nearctic.

Members of the leechi Group have depressions on the pronotum (posterointernal foveolae),
whereas marginicollis Group members lack these foveolae. This may seem a rather
insignificant distinction, however, aedeagal structure in the two groups more-or-less
corroborates the dichotomy.

Inferring phylogenies of many of the sublineages of Hydraena is complicated by the
existence of “clusters” of species, the members of which can reliably be distinguished from one
another only on the basis of aedeagal structure. These “clusters” occur in every major lineage
and, since they lack external derived character states (observable, at any rate), greatly hinder
an already difficult task. With this in mind, the reader should view the following phylogenies as
very preliminary steps in determining relationships, and as “road maps” for further study.

The circulata Group.

This group contains several species whose members cannot be reliably distinguished
externally. For the most part, the group displays “clusters” of similarly shaped aedeagi which,
it seems logical to assume, are indicative of phylogenetic relationships. Within these “clusters”
however, variation of form is such that morphoclines are not readily apparent, and phylogenetic
inference is of necessity highly speculative. Nevertheless, I feel the genitalic data are
acceptable for reconstruction of a phylogeny.

I have arranged the species of the circulata Group in four complexes based upon similarities
in the aedeagus (Figs. 163C,164A,B,165A,B) (numbers given in parentheses below refer to
those given in the phylograms). Males of Hydraena circulata (3) and those of the three other
species in its complex (Fig. 164A) have the transparent lobe at the apex of the aedeagus rather
well developed in relation to the size of the apical filament which arises from the lobe;
additionally, these species have long and dense setae on the parameres (Figs. 22A-E). Males of
Hydraena angulicollis (4) and those of the two other species in its complex (Fig. 164B) have

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441

LEECHI GROUP
MARGINICOLLIS GROUP
CIRCULATA GROUP
PAEMINOSA GROUP

A

i

LEECHI SUBGROUP
ALTERNATA SUBGROUP
SCINTILLABELLA SUBGROUP
PARTICEPS SUBGROUP
ARGUTIPES SUBGROUP

B

3

CIRCULATA COMPLEX
ANGULICOLLI S COMPLEX
ATLANTICA COMPLEX
PENNSYLVANICA COMPLEX

O- MID-CRETACEOUS

C

2

MARGINICOLLIS SUBGROUP
ANISONYCHA COMPLEX
MEXICANA COMPLEX
JIVARO COMPLEX
MARGINICOLLIS COMPLEX
TRINDENSIS COMPLEX
COLYMBA COMPLEX

GEMINYA SUBGROUP

D

Figs. 163A - D, Proposed phylogeny of major sublineages of Hydraena. (A) group relationships. (B) leechi Group. (C)
circulata Group. (D) marginicollis Group.

the apex of the main-piece (not the apical lobe) heavily sclerotized on the right side, and more
or less enlarged (most greatly so in angulicollis ); as in the circulata complex, two of the three
species have long and dense paramere setae (Figs. 24C,D,29D). Males of Hydraena atlantica
(5) and six other species in its complex (Fig. 165 A) have the transparent lobe at the apex of the
aedeagus shaped similarly to that seen in the circulata complex, that is, the lobe is large in
relation to the size of the apical filament; however, the parameres of males in the atlantica
complex have very sparse and relatively short setae (Figs. 26 A, B). The fourth complex includes
species associated with Hydraena pennsylvanica (6) (Fig. 165B).

Males have the transparent lobe at the apex of the aedeagus small in relation to the apical
filament (Figs. 29A-C,30A,B); enlargement of the filament reaches its extreme in H. ancylis’,
H. sierra might at first appear to have a large apical lobe and a small filament, but apparently
the lobe has enlarged after elongation of the filament, as a comparison with the aedeagus of H.

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Perkins

Figs. 164A - B, Generalized geographical distributions and proposed phylogeny of Hydraena. (A) circulata Complex. (B)
angulicollis Complex.

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443

YOSEMITENSIS
ATLANTICA
PACIFICA
MIGNYMIXYS
CALI FORN ICA
PET I LA

QUADRICURVIPES

Figs. 165 A - B, Generalized geographical distributions and proposed phylogeny of Hydraena. (A) atlantica Complex. (B)
pennsylvanica Complex.

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vandykei clearly suggests, indeed, H. vandykei and H. sierra are more similar to one another
externally than either is to any other species of Hydraena.

I associate the circulata and angulicollis complexes on the basis of their common possession
of long and dense paramere setae, whereas the atlantica and pennsylvanica complexes are
united because of their short and sparse setae (Fig. 1 63C: 1 ,2). This grouping is not supported
by a synapomorphy.

Within the complexes, the following character states were used for forming sister-species
pairs and sister-groups (numbers refer to those in phylograms, Figs. 64A,B,lo5A,B): (7) H.
circulata- arenicola united on the basis of similarity of main-piece shape; (8) H.
occidentalis-tuolumne united on basis of expanded parameres; (9) H.

angulicollis-appalachicola united on basis of morphocline of increasing enlargement of apical
region on right side of main-piece; (10) H. yosemitensis is unique in possession of long spines on
the apex of the aedeagus (lateral view); (11) H. quadricurvipes is unique in the lack of a
slender apical filament of the aedeagus (externally H. quadricurvipes is unique among
circulata Group species in possession of arcuate meso- and metatibiae); (12) H.
calif ornica-petila united on basis of very slender main-piece of the aedeagus; (13) H.
atlantica- pacifica united due to overall aedeagal similarity; (14) H. pennsylvanica-ancylis
united based on mutual possession of very long apical processes; (15) H. vandykei-sierra united
because the apical lobe is attched to the slender apical process above the point where the latter
attaches to the main-piece.

Comparison of geographical distributions of the four complexes in the circulata Group
reveals two patterns. First, three of the groups have both an eastern and a western North
American component, which I view as evidence of vicariance caused by Pleistocene glaciations.
Secondly, all three complexes with an eastern component have two species each, one more
northernly and one more southernly distributed; two of these north-south pairs are
sister-species, which may also relate to Pleistocene glaciations.

The leechi Group.

Five Subgroups of the leechi Group are recognized, based upon external features. The
following character states are used to define the proposed monophyletic groups (numbers refer
to those in phylogram, Fig. 163B): (1) this grouping is based on general habitus similarity, I
cannot suggest a synapomorphic character state at this time; (2) pronotum with a scintilla
(Fig. 3 1C); (3) males with arcuate hind tibiae (Figs. 32D,E); (4) hind tibiae of males with a
brush of setae; (5) hind tibiae with two stiff spines; elytra with alternate intervals elevated; (6)
hind tibiae of males straight, lacking a brush of setae; (7) pronotum without a scintilla; (8)
anteromedian region of metasternum forming a ridge (Fig. 48D).

Of these criteria, I am confident that 2-5 and 8 represent synapomorphic characters,
whereas criteria 1,6 and 7 should be considered likely candidates for modification in future
evaluations of relationships in this lineage.

The leechi Subgroup. - This is well defined and quite distinctive by virtue of the arcuate and
setose hind tibiae of males. Within the lineage, however, differences in external features are
generally of an autapomorphic nature and consequently of no value in determining
sister-groups. The reconstructed phylogeny (Fig. 166) is based on both aedeagal
(Figs. 33A-D,36A-D) and external features, but principally the former. The following
character states are used (numbers refer to those in phylogram): (1) H. canticacollis is
characterized by shape of parameres, which is unique in the group, and setae are distributed

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445

along the entire dorsal edge of the parameres, not just near the apex and on the ventral edge as
in males of other species of the leechi Subgroup; (2) the aedeagus of H. scopula is unique in
development of a process near the apex, and in paramere shape; (3) I am unable at present to
suggest apotypic character states for these proposed monophyletic groups, which are based on
overall external and aedeagal similarity; this similarity however may be due to retention of
plesiotypic characters; (4) H. arizonica and H. breedlovei have the metatibiae of males
expanded in the region of the setal brush (Figs. 32D,G), which is considered a derived
condition; (5) H. scintilla and H. bituberculata are united based upon similarity in the
aedeagal apex.

Comparison of proposed phylogeny and generalized distributions (Fig. 166) reveals that
most sister-groups consist of a northern (southeastern Arizona and southwestern New Mexico)
and a southern (central Mexico) component (i.e., H. scopula- sister-group, H.
scintilla-bituberculata, and H. arizonica-breedlovei). Interpreted from a vicariance theory
viewpoint, this distribution suggests that some portion of the Sierra Madre Occidental
mountains (or an historical antecedent) is a likely candidate as a vicariance barrier.

The scintillabella Subgroup. - Males of this subgroup are similar to those of the leechi
Subgroup in that several species display only aedeagal differences. Consequently, the proposed
phylogeny (Fig. 167) is based almost entirely on these genitalic characters. In certain species
the aedeagus is so bizarre ( H . zapatina and H. colombiana, Figs. 39C,D) that similarities with
the other species are not readily apparent. This also suggests that several species in this lineage
still remain to be collected and studied. Reconstructing a phylogeny is further complicated by
the fact that five of the 17 species in this lineage are known from only female specimens. The
following character states are used to justify the proposed phylogeny (numbers refer to those in
phylogram); (1) this lineage has relatively simple aedeagi which are slender in lateral view and
lack intricate convolutions in the apical portion (Figs. 37B, 41A-D); (2) aedeagi in this lineage
are relatively broad in lateral view and have the terminal portion highly convoluted and
extremely complex (Figs. 38A-D,39A-D); (3) in this grouping, the aedeagal main-piece
extends as a process at its apex; (4) H. maureenae-H. ozarkensis united based upon high
degree of overall aedeagal similarity (Figs. 41A-C), additionally, these two species have
random punctures on the elytral disc, not serial rows as in the other species, and a basic overall
external similarity; (5) in H. exilipes-H. campbelli the right side of the aedeagal main-piece is
heavily sclerotized and extends well beyond the left side; (6) placement of H. sordida and H.
puncticollis is highly speculative as males are not yet known; (7) these species are proposed as
monophyletic because of the tendency of the aedeagus to have an elevated region upon which
the parameres insert (see lateral views, Figs. 38A-D); (8) the aedeagus of H. costiniceps
(Fig.39B) differs in basic structure from that of the aforementioned species, hence its
placement; uniting H. germaini, H. paraguayensis and H. plaumanni to this lineage is highly
suspect as males are not yet known for these species; (9) species in this lineage have the dorsal
process of the aedeagal main-piece well developed; (10) uniting H. zapatina and H. colombiana
is based on their very complex aedeagal structure (Figs. 39C,D), however, this placement is
highly provisional and will almost undoubtedly require modification when additional, related
species are found; (11) this dichotomy and the H. alterra- H. terralta sister-species pair are
quite obvious from the aedeagal similarities of these three species (Figs. 38A,C,D).

A comparison of phylogeny and generalized distributions reveals that the first dichotomy
corresponds with the northern (North and Central American) and southern (South American)
distributions, the only exception being H. zapatina , which may not actually belong in the

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Perkins

A

B

C

D

E

F

G

CANT ICACOLLI S

LEECHI

ARIZONICA

BREEDLOVE I

SCINTILLA

BITUBERCULATA

SCOPULA

Fig. 166. Generalized geographical distributions and proposed phylogeny of the leechi Subgroup of Hydraena.

lineage as herein proposed (see above). The distribution patterns of the H. maureenae- H.
ozarkensis-H. exilipes-H. campbelli lineage closely approximates that of species in the
Hydraena marginicollis Complex (see below). Concerning the South American species, the
phylogeny suggests that species from southeastern Brazil are more closely related to those from
Colombia and Peru than to those (somewhat) geographically intermediate species from
Paraguay, Bolivia and northern Argentina ( H . costiniceps, etc.). However, male genitalia are
not known for three of these species, so their phylogenetic placement is doubtful. Further,
additional species of this lineage from South America surely await discovery.

The particeps Subgroup. - Adults in this sublineage of the leechi Group lack a pronotal
scintilla. Externally they are all quite similar (except H. oblio , see below), the reconstructed
phylogeny (Fig. 168) being therefore based upon aedeagal structures. Character states below
are used to justify the proposed phylogeny (numbers refer to those of phylogram).

(1) Placement of H. oblio in this lineage is highly provisional, being based upon lack of a
pronotal scintilla. The pronotum is markedly punctate and microreticulate, which could be
considered a derived condition for this group. However, this sculpturing may also have resulted
in the secondary loss of a scintilla; the aedeagus (Fig. 44A) also differs considerably from that
of other species in this lineage, and perhaps indicates relationship with certain species in the
scintillabella Subgroup. A more defendable phylogenetic placement of H. oblio must await
further data. (2) Males of this lineage have the parameres originating above the base of the
aedeagus. (3) Overall aedeagal similarity of males of these three species (Figs. 44B-D),
includes presence of a lobe on the left side of the aedeagus, which is considered apotypic. (4)

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447

Fig. 167. Generalized geographical distributions and proposed phylogeny of the scintillabella Subgroup of Hydraena.

Males have the parameres originating just below the modified apex of the aedeagus
(Figs. 43A-D,45B). In H. orcula the parameres originate lower on the main-piece, but this is
thought to be secondarily derived. Males of three of the four species have a slender process at
the aedeagal apex, which are considered homologues {H. youngi is the exception). (5) These
three species share an aedeagal lobe (see lateral views of Figs. 43A-D; lobe lies in front of right
paramere). (6)7/. youngi is thought to be a highly derived member of its lineage, with adults
characterized by an unusual, very linear body form and scabrous sculpture on the pronotum.
The aedeagus (Fig. 45B) is also quite unusual, I suspect a result of fusion and reduction of
various parts (cf.. H. particeps aedeagus, Fig. 43 A). The morphological gap in aedeagal and
external features between H. youngi and the species of its sister-group suggests that several

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species have become extinct in this lineage. (7) H. decui and H. particeps are united on the
basis of overall aedeagal similarity (Figs. 43A-C). One can mentally visualize the bending and
reduction necessary to derive the H. decui aedeagus from an H. particeps-Mke precursor. The
aedeagus of H. orcula males does not easily lend itself to a third step in this type of
modification, hence its very reduced structure is thought to reflect early divergence of the stock
from which it descended (most of which remain to be collected and described). (8) Males of H.
guadelupensis, H. spangleri and H. punctata display three transformation series in aedeagal
features (Figs. 44B-D): development of a sclerotized sinuation on the dorsal surface between
the parameres (maximum expression in H. punctata)', increasing width of main-piece (H.
punctata the extreme); and increasing slenderness of apical filament ( H . punctata again the
extreme). Based on out-group comparison with the other species of the particeps Group, the
slender aedeagus which lacks a sclerotized sinuation between the parameres would appear
plesiotypic. This suggests that direction of change was from H. guadelupensis to H. spangleri
and finally to H. punctata , and consequently the latter two species are considered
monophyletic.

Comparison of the proposed phylogeny and generalized distributions (Fig. 168) reveals that
the Caribbean species, H. guadelupensis and H. decui, are related to North and South
American lineages, respectively. When traced backward, however, both lineages “retreat” in a
southern direction, indicating that ancestral species had Central or South American
distributions. Are the Caribbean distributions a result of vicariance caused by formation of
these islands (see Rosen’s hypothesis, 1975), or due to dispersal and divergence after insular
formation? If the species dispersed to the islands and then diverged, it would seem logical that
the southernmost Caribbean species, H. guadelupensis, would have its sister-species in northern
South America. Likewise, the species from Cuba, H. decui, would probably have its
sister-species in Florida and adjacent areas of North America. The exact opposite is true,
however, as H. guadelupensis is related to H. spangleri and H. punctata of North America,
whereas H. decui is related to H. particeps and H. orcula of South America. One wonders if
further collecting will expand the distributions of these Caribbean species.

The argutipes Subgroup. - The reconstructed phylogeny (Fig. 169) of this lineage is based
on both external and aedeagal characteristics (numbers below refer to those of phylogram). (1)
H. cuspidicollis differs both externally and genitalicaly from the remaining species in this
lineage. Anterior angles of the pronotum (Fig. 48C) are produced, males have a brush of setae
on the hind tibiae, and the protibiae are shaped uniquely (Figs. 61G,H), all of which are
considered apotypic for this lineage.

The aedeagus of H. cuspidicollis (Fig. 45A) is unique in that the left paramere is much shorter
than the right, and the main-piece extends well to the left of the mobile-piece. (2) Synapotypic
character states are not known for this lineage. (3) Synapotypic character states are not
presently known for this lineage either. (4) H. mazamitla is here separated based upon the
dissimilarity of its aedeagus (Fig. 46B) from aedeagi characteristic of other species. (5) This
group of species is proposed as monophyletic based on the large size of the opening at the base
of the aedeagus, a very unusual condition and almost surely apotypic for this lineage. (6) H.
bractea and H. bractoides share a very similar and unusual habitus, expanded hind tibiae in
males, and very large metasternal plaques. There is little question they are sister-species. (7)
Bifid right parameres (Figs. 47 A, B) plus ochraceous legs are derived features shared by H.
argutipes and H. prieto. (8) Males of this lineage have lobe-shaped right parameres
(Figs. 46A,C,D). (9) H. oaxaca and H. scolops males share an unusual lobe between the left

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OBLIO
SPANGLER I
PUNCTATA
GUADELUPENSIS
ORCULA
SAHLBERG I
DECUI
PARTICEPS
YOUNG I

ISTOCENE

Fig. 168. Generalized geographical distributions and proposed phytogeny of the particeps Subgroup of Hydraena.

paramere and the main-piece. This lobe inflates when the aedeagus is transferred from glycerin
to water.

Interpretation of the generalized distributions (Fig. 169) in light of the proposed phylogeny
is difficult due to extensive sympatry. The most clearly defined section of the phylogram (5) is
composed of a northern (7) and a southern (8) component, which may suggest a geographically
intermediate barrier that was effective in the past.

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The marginicollis Group.

Although the marginicollis Group contains some externally distinctive species, there are
many species whose diagnostic features are restricted to aedeagal characters. Two sublineages
(Fig. 163D) are recognized, based upon characters of the ventral surface. In one sublineage, the
geminya Subgroup (1), the prosternal carina is separated from the procoxae by a narrow shelf,
and the mesosternal intercoxal process is broad (Figs. 63 A, F). In the marginicollis Subgroup
the pro-and mesocoxae are less widely separated (Figs. 54B,I). These differences relate, in
general, to different habitats occupied by these groups (see classification section of the geminya
Subgroup). More narrowly separated coxae must be considered the plesiotypic condition,
therefore synapotypy of the marginicollis Subgroup remains to be demonstrated.

Fig. 169. Generalized geographical distributions and proposed phylogeny of the argutipes Subgroup of Hydraena.

The marginicollis Subgroup. - Six species complexes based upon aedeagal similarities are
included in this lineage. Proposed phylogenetic relationships of these complexes (Fig. 163D)
reflect an apparent transformation series of positions of the parameres. In the anisonycha and
mexicana Complexes (2,3) the parameres originate at or very near the aedeagal base (//.
mexicana Fig. 5 1C); males of the jivaro Complex (4) have the parameres near the basal 0.33 of
the main-piece {jivaro , Fig. 52C); in the marginicollis and trinidensis Complexes (5) the left
paramere is further from the base than is the right {H. trinidensis , Fig. 53C); finally, in the

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Fig. 170. Generalized geographical distributions and proposed phylogeny of the mexicana Complex of Hydraena.

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Figs. 171 A - B, Generalized geographical distributions and proposed phylogeny of Hydraena. (A) geminya Subgroup. (B)
jivaro Complex.

colymba Complex (6) both parameres originate above midlength of the main-piece ( H .
colymba. Fig. 60A).

H . anisonycha (2) is placed as the sister-group of the other complexes because of highly
unusual external characteristics (see species diagnosis section); also, although parameres attach
near the base of the aedeagus (the primitive condition, Fig. 58B) as does the mexicana

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states as follows: (1) the main-piece is straight near the apex in limpidicollis and newtoni
(Figs. 49C,D)(these two species are also unique in that the pronotum is testaceous); (2) in these
species the main-piece extends to the right at its apex; (3) these species are assembled on
overall aedeagal similarity, and the assembly is provisional (Figs. 49A,B,51 A-D).

Comparison of generalized distributions and phylogeny (Fig. 170) reveals no overlap
between any of the sister-species pairs. Since this reconstruction is provisional, relationship of
the Caribbean species ( H . haitensis and H. perkinsi ) to those from South America ( H .
quechua and H. tucumanica ) must also be viewed as tentative.

The reconstructed phylogeny for the jivaro Complex (Fig. 17 IB) is based on aedeagal
similarities (2) and testaceous labrum (1). Although aedeagi of H. hyalina and H. grouvellei
males (Figs. 52A,64A) are similar to those of the remaining three species, I am not confident
that their proper phylogenetic position is within this lineage. Clarification of their placement
must await discovery of additional, more closely related species. Relating generalized
distributions to the phylogeny should be restricted to H. jivaro, H. anaphora and H.
premordica aedeagi, (Figs. 52B-D) due to the highly speculative placement of H. grouvellei
and H. hyalina.

Marked similarity of aedeagal form of H. trinidensis and H. browni males (Figs. 5 3 A-D) is
the basis of the reconstructed phylogeny for the trinidensis Complex (Fig. 172A).

The reconstructed phylogeny for the marginicollis Complex (Fig. 172B) is based upon
aedeagal similarities which appear to be synapotypic (Figs. 55 A-D, 58 A): (1) terminal mobile
piece with a vesicle; (2) left side of main-piece with a heavily sclerotized lobe; (3) terminal
mobile piece with two processes at its apex; (4) overall aedeagal similarity (I cannot
demonstrate that this latter criterion is synapotypic).

Comparison of the generalized distributions (Fig. 172B) with the phylogeny reveals that the
Central and North American species form the sister-group of the South American species. I
suspect that the ancestor of H. marginicollis-pulsatrix-longicollis had a wide distribution
around the Gulf of Mexico, underwent vicariance to form H. marginicollis and the ancestor of
H. pulsatrix-H. longicollis ; a subsequent vicariant event caused the formation of H. pulsatrix
and H. longicollis.

The reconstructed phylogeny for the colymba Complex (Fig. 173) is based upon the
following criteria (numbers refer to those in phylogram): (1) overall aedeagal similarity
(Figs. 60A-D,62A); (2) large body size, pronotum lacking macula, overall aedeagal similarity
(Figs. 62B-D); (3) metatibiae of males enlarged; (4) similarity of terminal mobile piece; (5)
left paramere reduced in size. With the possible exception of the placement of H. sabella, I am
fairly confident that this phylogeny closely approximates the true relationships of this complex.

In general, the distributions (Fig. 173) of species in the mountains of Chiapas, Mexico, and
those further south in Central America equate with the first dichotomy of the lineage. The high
degree of sympatry within the two sublineages, however, prevents further generalizations.

The geminya Subgroup. - The reconstructed phylogeny (Fig. 171 A) of the three species in
this lineage is based upon similarity in aedeagal form of H. chiapa and H. geminya males
(Figs. 64B-D). The widely separated ranges do not permit analysis of the pattern, and probably
reflect inadequate sampling of appropriate habitats.

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Genus Spanglerina

The two sister-species pairs of this genus are clearly indicated by small size, bicolored head,
and aedeagal similarities of S. brevis-frondsicola (Fig. 174:1), and large size, unicolorous head
and aedeagal similarities of S. ingens- fluvicola (2).

Rather close similarity of sister-species and distribution patterns suggest a single vicariance
event between present day distributions of S. ingens and S. fluvicola , which could also have
formed geographical isolates of the S. brevis-frondsicola stem species.

Genus Limnebius

Adults of Limnebius are extremely similar to one another externally, reliable determinations
being based almost entirely on aedeagi, which are highly dissimilar.

Likewise, the reconstructed phylogeny (Fig. 175) must be based entirely on aedeagal form.
Aedeagi of males in the upper section of the first dichotomy (1) ( L . borealis , etc.) have the
apical portion more or less lobate and mobile (Figs. 70,71,72A,73C), whereas the apical portion
of the aedeagus of the sister-group (2) is generally narrower and firmly affixed to (not hinged
with) the basal part (Figs. 72C,D,73A,B). Sister-species are based upon similarities in aedeagal
form, some of which are quite obvious (L. sinuatus-utahensis, L. borealis-arenicolus , L.
piceus-alutaceus ), and in other instances rather obtuse (e.g., L. mitus-angustulus) . Lack of
external characteristics to corroborate the proposed relationships impose a low level of
confidence on the phylogram.

The most obvious correspondence between phylogeny and distribution pattern is relationship
of eastern species of United States to those in western North America, not to those of Mexico
and Texas. The Mexican and Texan species have two sister-group relationships with the species
of the western United States: L. leechi - ( aridus - mexicanus-octolaevis) and L. texanus -
( arenicolus-borealis ). Therefore, as is seen in Ochthebius , the geographical area of southern
California and southern Arizona appears a likely location for an event causing vicariance
during the past. Also suggestive of a pattern seen in Ochthebius is the allopatric distributions of
L. arenicolus-borealis , separated by areas of Oregon and Washington (the two subpopulations
of alutaceus discussed in the classification section also reflect this presumed barrier).

Genus Gymnochthebius

Proposed phylogenetic relationships of the Subgroups of Gymnochthebius are illustrated by
Fig. 176B. Numbers on the phylogram represent the following synapotypic character states: 1)
absence of hydrofuge pubescence from posterior 0.50 of abdominal sternum 5 and from median
area of metasternum; 2) absence of hydrofuge pubescence from anterior 0.50 of of abdominal
sternum 5; 3) loss of elytral striae; 4) unusual pronotal form (see Figs. 89D,E); 5) markedly
microreticulate pronotum; and 6) similarity in aedeagal form. Unification of the nitudus-
laevipennis Subgroups as monophyletic requires verification as I cannot suggest a synapotypy
at this time. The oppositus Subgroup is obviously the more highly apotypic member of this trio.

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Fig. 173. Generalized geographical distributions and proposed phylogeny of the colymba Complex of Hydraena.

but there is no morphocline which will allow it to be united with either the nitidus or
laeyipennis Subgroup: I therefore view its distinctiveness as resulting from early divergence
from the nitidus Group stock. The three species in the plesiotypus Group retain presumed
primitive features of the pronotum and ventral pubescence, but the close resemblance of the
aedeagi indicates monophyly.

Generally speaking, Gymnochthebius displays increasingly derived morphological states of
the Subgroups northward from Chile to the United States. Thus, the germaini Subgroup is
intermediate in pronotal form between the plesiotypic plesiotypus Subgroup of Chile and
Argentina and the apotypic laevipennis and oppositus Subgroups of Central America, Mexico
and southern United States; likewise, the germaini Subgroup is geographically intermediate
between the aforementioned groups.

The plesiotypus Subgroup. - Primitive form of the pronotum of G. plesiotypus , which
resembles that of certain Ochthebius (sensu stricto) species, has been discussed previously. The
closely similar body form and aedeagi of G. jensenhaarupi and G. octonarius clearly indicate
monophyly with G. plesiotypus. The monophyly of G. jensenhaarupi and G. octonarius (1) is
based upon their close external and genitalic resemblance. The allopatric distribution patterns
of the three species also suggest the phylogeny as proposed (Fig. 176A).

The germaini Subgroup. - Proposed common ancestry in this lineage (Fig. 177) is based
upon similarities in the aedeagus and trends toward reduction of pronotal punctation

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Fig. 174. Generalized geographical distributions and proposed phylogeny of Spanglerina species.

( e.g.,G.tectus-topali ). Members of several species differ noticably only in genitalic
characteristics, or vary externally such that the genitalia must be used in identification. This,
plus the complex sympatric distribution patterns of the Chilean species makes phylogenetic
inferences difficult and consequently of a low level of confidence. The body form of G. bartyrae
(1) (Fig. 80B) is quite dissimilar from body form characteristic of the remaining species.
Likewise, G. compactus (2) with its compact body appears distinct from the remaining species
of its assemblage. I have seen an additional species (undescribed-no males) related tq G.
compactus from Uruguay, suggesting that these two species may represent a monophyletic
vicariant group in the highlands of Brazil and adjacent montane areas of eastern-southern
South America. Proposed sister -species pairs for the remaining species of the germaini
Subgroup are based upon similarities in shape of the aedeagal apex, the two sides of the “fork”
being of unequal length in G. germaini and G. bisagittatus (4) (Figs. 85A,95B), and of equal
length (3) in the remaining species. Illustrations (Figs. 84A-D,88B) of the remaining species
show similarities between various pairs, but I cannot at present demonstrate defendable

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O- MID-CRETACEOUS
□- MIOCENE
a- PLEISTOCENE

K OCTOLAEVIS
L MEXICANUS
M ARIDUS
N LEECHI
0 MITUS
P ANGUSTULUS

Fig. 175. Generalized geographical distributions and proposed phylogeny of Limnebius species.

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NITIDUS SUBGROUP
LAEVIPENNIS SUBGROUP
OPPOSITUS SUBGROUP
GERMAINI SUBGROUP
RETICULATUS SUBGROUP
PLESIOTYPUS SUBGROUP

B

Figs. 176A - B. (A) generalized geographical distributions and proposed phylogeny of the plesiotypus Subgroup of
Gymnochthebius. (B) proposed phylogeny of major sublineages of Gymnochthebius.

synapotypies. We are clearly far from a definitive statement of the phylogenetic relationships of
the germaini Subgroup.

The reticulatus Subgroup. - This highly distinctive Subgroup is currently represented by a
single sister-species pair (Fig. 90B). The morphological distance separating this Subgroup from
its sister-group {germaini Subgroup) suggests that additional related species probably remain
to be discovered.

The oppositus Subgroup. - Only two species are presently known for this highly derived
group (Fig. 94A).

The laevipennis Subgroup. - There is an obvious trend toward reduction of dorsal sculpture
in this group, as adults of all species lack well impressed rows of elytral punctures. This trend to
smoothness is also seen in the pronotum, reduction of foveae presenting a morphocline which
can be used to infer relationships (Fig. 178): G. crassipes-laevipennis are united (2) by loss of
lateral (foveate) depressions, and G. crassipes-laevipennis- maureenae are united (1) by loss of
posterior foveae. By out-group comparison, the foveate condition is primitive. The allopatric
pattern of distribution can also be interpreted as suggesting this branching sequence.

The nitidus Subgroup. - The sister-species pair nitidus-falli (Fig. 179:1) is based upon the
relatively wide median piece of the aedeagus. Shape of the median piece in G. fossatus is more
similar to that of species in the germaini Subgroup. Externally, G. falli and G. fossatus are
more similar, but this similarity suggests symplesiotypy, G. nitidus being clearly the more
divergent species of the trio. One possible scenario is that the ancestor of the group was
probably distributed in Central and/or northern South America, spread northward, forming as
the result of a vicariant event G. fossatus plus the ancestor of G. falli-nitidus. The latter
subsequently differentiated, with G. fossatus more recently expanding its range northward and
southward to its present extent.

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Fig. 1 77. Generalized geographical distributions and proposed phylogeny of the germaini Subgroup of Gymnochthebius.

Fig. 1 78. Generalized geographical distributions and proposed phylogeny of the laevipennis Subgroup of Gymnochthebius.

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Fig. 179. Generalized geographical distributions and proposed phylogeny of the nitidus Subgroup of Gymnochthebius.

Genus Ochthebius

Ochthebius species in the New World are grouped into two subgenera, Ochthebius ( sensu
stricto) and Asiobates (see section on classification). Ochthebius (sensu stricto) is best

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represented in western North America, but has one major sublineage ( biincisus Group) which
has diversified in Mexico and Central America. Ochthebius (Asiobates) also has these two
geographical components, but they are approximately equal in species numbers, although the
Mexican components are more morphologically diverse.

Subgenus Ochthebius

The proposed branching sequences of the major sublineages of Ochthebius ( sensu stricto )
(Fig. 181 B) are based primarily on form of pronotum, especially shape of the anterior margin
(1). An exception is separation of O. benefossus from the remaining species based on unusual
sides of the pronotum, which have the hyaline border entirely within the sinuation (2)
(Fig. 96D). Additionally, the apical mobile piece of the aedeagus (Fig. 131 A) differs from the
basic form of the remaining species. The interruptus and borealis sublineages are united by the
straight anterior margin of the pronotum (Fig. 1 82B: 1 ). The rectus Subgroup is joined to the
aforementioned by the nearly straight anterior margin, but is distinct from those in shape of the
pronotal sides (2) (Figs. 96A,112D-F). The bisinuatus Group has the anterior margin of the
pronotum bisinuate, which is more closely similar to the form seen in the interruptus Group
than that of the biincisus Group, hence its placement as the sister-group of the former
(Fig. 181 B:3). Finally, the biincisus Group is treated as the vicariant (southern vs. northern)
sister-group of the interruptus + bisinuatus Groups (Fig. 181 B:4) based on the development of
postocular emarginations and processes on the anterior margin of the pronotum
(Figs. 125A-F,128A).

Fig. 180. Generalized geographical distributions and proposed phytogeny of the biincisus Group of Ochthebius (sensu
stricto).

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Obviously I am not applying constraints of equal ranking of sister-groups (e.g., biincisus
Group ranked equal with interruptus Group plus bisinuatus Group), the reason being that this
proposed phylogeny is meant as the first phase in elucidation of phylogenetic relationships of
the sublineages of Ochthebius (sensu stricto), the groups therefore being treated as working
units. Equally obvious is lack of synapotypies for the proposed groups, these being based
primarily on morphological trends; one trend (morphocline) leading to a markedly bisinuate
anterior margin of the pronotum ( O . calif ornicus. Fig. 116D) and the other leading to well
developed postocular emarginations and processes ( O . mexcavatus , Fig. 128A).

Figs. 1 8 1 A - B. (A) generalized geographical distributions and proposed phylogeny of the bisinuatus Group of Ochthebius
(sensu stricto ). (B) proposed phylogeny of major sublineages of Ochthebius (sensu sricto).

Both of these groups are thought to be derived from an ancestor with a straight or slightly
arcuate anterior margin, hence the interruptus Group, which is defined by this criterion, must
be considered untested with respect to apotypic characters in common. One possible scenario to
explain structure and distributions is: 1) a widely spread species or group of species (with
straight anterior margin) diverged to form a northern and southern group; 2) the southern
group diverged to form the biincisus Group (anterior margin with postocular processes and

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emarginations); 3) the northern group (concurrently perhaps) diverged to form the more boreal
sublineage and the western bisinuatus lineage; 4) the boreal sublineage expanded its range
westward, then underwent a vicariant event to form the rectus Subgroup in the west and the
interruptus-borealis stock in the north; 5) the process repeated, with the formation of the
interruptus and borealis Subgroups.

The benefossus Group

This monotypic group and O. ( Asiobates ) putnamensis are the only members of the genus
restricted to eastern North America (Figs. 99C,186). O. benefossus bears a resemblance to
Palearctic species in the subgenus Henicocerus (see comments in classification section); this,
plus absence of other species in eastern North America suggests an ancient, Laurasian
distribution pattern. Further study will probably demonstrate that O. benefossus is more closely
related to Palearctic species than to any of the New World.

The biincisus Group

The proposed phylogeny of this lineage, which contains more tropical elements than any
other sublineage of Ochthebius (sensu stricto ) Leach is illustrated by Fig. 180, the numbers
representing the following characteristics (presumed apotypic): 1) postocular emarginations
present; 2) absence of hydrofuge pubescence on abdominal sternum 6; 3) confluent posterior
foveolae of pronotum ( a reversal in O. biincisus ); 4) not demonstrable at this time; 5) reduction
of pronotal microreticulation; 6) convex lateral depressions; 7) deep postocular emarginations;
8) loss of median groove; and 9) similarities of aedeagi and habitus.

Some dichotomies have one component north and the other south of the Arizona-Mexico
boundary (presently an arid region). Examples are (northern component of each pair given
first): O. gruwelli- arizonicus-biincisus vs. O. mexcavatus; and O. alpinopetrus-
spanglerorum vs. O. attritus-batesoni. Similarity, there is a “dividing line” near the Tropic of
Cancer in Mexico which could be viewed as evidence for a single vicariant event resulting in O.
tubus vs. O. pauli\ and O. madrensis vs. O. obscurus.

Distribution of the sister-species pair O. attritus- batesoni, the former circum-Caribbean,
the latter Galapagian, is suggestive of an “eastern Pacific-Caribbean generalized track” (see
Rosen, 1975). However, this inference should be tempered by recognition that O. attritus is a
halophilic species (living in salty pools near beaches) and therefore is more likely to develop an
extensive range (as is indicated by the seemingly disjunct Brazilian population). Consequently,
the marine barrier between the Galapagos and Central America may be “perfectly matched”
for the stem species of this pair, allowing the “chance survivors” model to operate (see
discussion in introduction to this section). On the other hand, Rosen (1975) has illustrated this
distribution pattern with such divergent organisms as isopods, shrimps, crabs and rats. It would
seem highly unlikely that these very different organisms, and also the O. attritus-batesoni stem
species, would have the same vagility and rate of genetic divergence which would allow this sea
barrier to function in each example (via the chance survivors model).

The bisinuatus Group

The bisinuatus lineage trends toward reduction in body size and development of rough
pronotal sculpture, the latter trend reaching its extreme in O. crenatus. This trend toward
rough sculpture is one of the major transformation series upon which the proposed phylogeny
(Fig. 181 A) is based. The criteria are (numbers refer to those on phylogram): 1) bisinuate

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anterior margin of the pronotum (arcuate margin assumed to be the plesiotypic state; 2) I
cannot suggest a synapotypy for this group, though O. richmondi is isolated by retention of a
more primitive habitus; 3) development of widely produced lateral depressions of the pronotum
which terminate abruptly posteriorly (Figs. 116A,C); 4) morphocline of pronotal roughness;
and 5) crenulations present on anterior margin of pronotum.

Analysis of distribution is complicated by extensive sympatry. However, if sympatry of
sister-groups is evidence of dispersal following a vicariant event (Platnick, 1976; Platnick and
Nelson, 1978), then it is apparent that the most likely geographical location for such an event
(Fig. 181 A) is the general vicinity of southern Oregon and southern Idaho. This area separates
most of the components of the first dichotomy (except O. californicus) and also separates
(discounting area of sympatry) the sister-species pair O. crenatus-californicus.

A RECTUS
B RECTICULUS
C RECTUSALSUS

A

B

Figs. 182A - B. (A) generalized geographical distributions and proposed phylogeny of the rectus Subgroup of Ochthebius
(sensu stricto). (B) proposed phylogeny of major sublineages of the interruptus Group.

The rectus Subgroup. - Members of these three species present a habitus
(Figs. 98A,112D-F) quite distinct from the other related sublineages of Ochthebius ( sensu
stricto ). One species, O. recticulus , is known only from the overflow area of a thermal spring in

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California; the second, O. rectusalsus, is apparently adapted to salty ponds near beaches; and
the third, O. rectus , is widespread in western North America, frequently found in saline pools.

The reconstructed phylogeny (Fig. 182A:1) unites O. rectus and O. recticulus based upon
similarities of the aedeagus of males (Figs. 1 13B,C,1 14A). One possible scenario consistent
with the distributions, habitats and proposed phylogeny is as follows: 1) the stem species of the
lineage was widespread in western North America, containing some ecological components
more highly adapted to saline water; 2) a vicariant event, such as decrease in temperature,
causes a southward range contraction, leaving a component in warmer coastal ponds (latter to
diverge to become O. rectusalus ), a very small population at Wilbur Hot Springs or other
geographically approximate thermal springs (Wilbur Hot Springs has a high degree of
endemicity- further support for a vicariance hypothesis) (this component later to become
recticulus ), and finally a southern, less ecologically restricted component (rectus); 3) under
more favorable environmental conditions, the less ecologically restricted species, O. rectus ,
expands its range to the present limits.

The interruptus Subgroup. - Species of this lineage are restricted to western North
America; all members have a straight or arcuate anterior pronotal margin and distinct posterior
pronotal foveae.

The reconstructed phylogeny (Fig. 183) is based upon similarities in habitus (1), pronotal
punctation (3), and color (2) (O. pacificus-arenicolus are generally black, the other three
species brownish) (Figs. 97A-E).

As was seen in the bisinuatus Group, there is a complex pattern of sympatry, especially in
California. Further, the vicariant boundary proposed for the bisinuatus Group (southern
regions of Oregon and Idaho) also appears to be that region most likely involved in vicariance
of interruptus Subgroup species.

The distribution pattern of O. lecontei is unique among the hydraenids of this region, from
which might be inferred that the O. lecontei-sierrensis species pair is an example of the
“chance survivors” model. These two species are separated by the Great Basin.

The borealis Subgroup. - This lineage contains primarily cold adapted species which are
typically found in pond habitats. Two species, O. kaszabi and O. marinus are the only members
of the family known to have a holarctic distribution pattern.

The reconstructed phylogeny (Fig. 184) is based upon the following synapotypies: 1)
confluent posterior foveae of the pronotum; 2) loss of median groove; 3) development of
confluent pronotal foveae of a side to form sinuate lines; 4) similarities of aedeagi; and 5)
similarities of pronotal microreticulation.

Remains of O. marinus (or O. kaszabi ) in late Pleistocene deposits of Canada (age of
deposits = 100,000 years; see comments in “Zoogeography at the Generic Level” section),
establish that at least one of these two species had evolved prior to the Pleistocene. This
information plus present day distributions suggests that both species were holarctic prior to the
Pleistocene. What effect upon speciation in this Subgroup did glacation have? Perhaps the stem
species of O. marinus-uniformis-borealis was “cleaved” by advancing ice sheets to form O.
marinus and the stem of O. uniformis-borealis.

A problem species in this lineage is O. lineatus which, unlike the remaining species, extends
southward into tropical regions where it is a rather distinctive morph (see section on
classification). Possibly possession of confluent posterior foveae of the pronotum (which are
used to place it in the borealis lineage) is an example of convergence, as the southern morph of
this species in other respects resembles O. attritus of the biincisus Group.

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A LECONTE I
B S I ERRENS I S
C INTERRUPTUS
D PACIFICUS
E ARENICOLUS

Fig. 183. Generalized geographical distributions and proposed phylogeny of the interruptus Subgroup of Ochthebius (sensu
strieto).

A KASZABI
B MARINUS
C UNIFORMIS
D BOREALIS
E LINEATUS

Fig. 184. Generalized geographical distributions and proposed phylogeny of the borealis Subgroup of Ochthebius ( sensu
strieto ).

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Subgenus Asiobates

The subgenus Asiobates includes the puncticollis Group, which contains large, coarsely
punctate adults with a similar aedeagus, and the discretus Group, including small adults,
generally less coarsely punctate and with a different aedeagal type. The reconstructed
phylogeny (Fig. 185B) of the Groups and Subgroups is based upon the following (numbers
refer to those given in the figure): 1) aedeagus with a process on terminal mobile piece
(( discretus Group); 2) body large, males similar in details of the aedeagus (Figs. 144A-E); 3)
anterior foveae of pronotum present or region coarsely punctate and depressed; 4) anterior
foveae, and also posterior foveae in some specimens, absent, body form and aedeagus similar.

The allopatric distribution of a northern and a southern component of nearly all
sister-groups within this lineage invites the inference that a single vicariant event in the
southwestern United States (or a cyclic environmental change in this region) has had a marked
influence on dichotomies within the lineage. For example, the following north-south
sister-groups are separated by this geographic region: discretus Subgroup - reticulocostus
Subgroup; cribricollis Subgroup - similis Subgroup; puncticollis species - angularidus species.

The puncticollis Group.

This lineage of distinctive, large (about 2.50 mm long) species is restricted to the western
United States, with one disjunct species ( O . angularidus) in the Rio Grande River drainage of
southern Texas and northern Mexico. The species O. martini-leechi are united (Fig. 185A:1)
by the relatively flattened pronotum (a more convex type considered primitive), whereas O.
puncticollis-angularidus are united (2) by general habitus resemblance, including well
developed pronotal foveae, and genitalic resemblance.

Distribution patterns and proposed phylogeny suggest two vicariant events, the first
occurring in southern California and adjacent Arizona, dividing the stem species of the Group
into a population in the northern coastal region of California (O. martini-leechi stem species)
and a population farther south (O. puncticollis-angularidus stem species); and a second,
subsequent vicariant event occurring somewhere between the current ranges of O. puncticollis
and O. angularidus causing that dichotomy (with subsequent range expansion of O.
puncticollis to its present limits).

Given a different phylogeny, for instance uniting O. leechi-puncticollis-angularidus as a
monophyletic group could suggest this scenario: an ancestral species, with a distribution similar
to that of O. puncticollis today, moving southward due to decrease in temperature, leaving
small populations in warmer coastal areas (to become O. martini ), in thermal springs (to
become O. leechi ), followed by a northward expansion of the southern population under
favorable conditions, and subsequent vicariance of O. puncticollis-angularidus.

The discretus Subgroup. - The reconstructed phylogeny (Fig. 186) is based primarily upon
similarities in aedeagal features (2,3) and secondarily upon habitus resemblances (1). The
proposed position of O. putnamensis is provisional as males are unknown for that species.
Overlapping patterns of sympatry in Oregon make that region a likely candidate for an inferred
vicariant event.

I have seen fossil fragments of a species which is probably O. discretus or O. hibernus from
Ontario (age ca. 70,000 years - see Morgan, 1972), indicating a more eastern distribution

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469

DISCRETUS SUBGROUP
RETICULOCOSTUS SUBGROUP
CR IBR I COLLI S SUBGROUP
S I MI LI S SUBGROUP
PUNCT I COLLI S GROUP

B

Figs. 185A - B. (A) generalized geographical distributions and proposed phylogeny of the puncticollis Group of
Ochthebius ( Asiobates ). (B) proposed phylogeny of major sublineages of O. ( Asiobates ).

pattern in the past for this Subgroup. This may partially explain the disjunct distribution of the
eastern O. putnamensis.

The similis Subgroup. - The single species known for this group, based upon external
features and aedeagus, is closely related to the cribricollis Subgroup (Fig. 187A) (see
classification section for further comments).

The cribricollis Subgroup. - Only two species are currently known for this group, both of
which have a northern distribution pattern (Fig. 187A). Previous authors placed O. cribricollis
in the subgenus Homalochthebius (see section on classification).

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Fig. 186. Generalized geographical distributions and proposed phytogeny of the discretus Subgroup of O. ( Asiobates ).

The reticulocostus Subgroup. - Lack of correspondence between external resemblances and
aedeagal structure in this group makes phylogenetic inference difficult. For example, although
O. reticulocostus and O. mexicanus are similar in possession of costate elytral intervals,
certainly a derived character state in this group, the other external features of these two species
(Figs. 140A,C) and the aedeagi (Figs. 141 A, C) are quite dissimilar. A number of autapotypic
characters, such as the two apical aedeagal processes of O. apache , the lack of a process in O.
mexicanus, and fusiform body shape of O. apicalis, do not aid determination of sister-species
relationships (although they may as further species are discovered and described). The basal
lobe of the aedeagus common to O. apache and O. reticulocostus must be considered primitive
as it is present in the out-group ( discretus Subgroup), however, absence of this lobe can be used
to unite O. mexicanus-browni(¥ig. 187B:3).

The phylogeny I have proposed (Fig. 187B) is based partially on body size and form (1), and
partially on aedeagal similarities (2). This phylogeny is provisional and I suspect that other, as
yet undescribed, species will eventually make possible an interpretation of the present confusing
pattern of morphological features.

Accepting this phylogeny, the distribution patterns suggest two locations for vicariant
events: 1) between the present distributions of O. apicalis and and O. reticulocostus, and 2)
between O. apache and O. reticulocostus. The latter region, near the Tropic of Cancer,
corresponds with that also suggested by components of the biincisus Group of Ochthebius
( sensu stricto) (see above). (I have made a conscious effort to avoid circularity inherent in
basing phylogeny on allopatric distributions and then using that phylogeny to support allopatric

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471

speciation.)

Genus Meropathus

The single New World species of this genus, M. vectis, is most closely similar to M.
campbellensis from the Campbell Island of the New Zealand subregion, and less so to M. chuni
from the Kerguelen Island group. However, evolutionary classification of these similarities
must await a complete review of the genus.

Genus Neochthebius

The two intertidal species currently known for this genus, N. granulosus from Japan and N.
vandykei from the Pacific coast of North America, are very similar sister-species.

Coincident Sister-Group Patterns, Vicariance Zones, and Endemism

“Sweet are the uses of adversity.”(Shakespeare, As you like it)

Croizat (1958, 1964), Croizat, Nelson and Rosen (1974), Rosen (1975, 1978) and Platnick
(1976) (among other papers by these authors) have used Croizat’s method of plotting
geographical distributions of species or monophyletic groups of species, then joining these
distributions by lines to form “tracks”.

Rosen (1975) states: “A track is no more than a line on a map connecting the disjunct
populations of a species or the disjunct species of a monophyletic group. Thus, a line may be
drawn between the distribution of a monophyletic group of species and that of its sister-group
of one or more species. Plotting on a map the distributions of many different animal and plant
assemblages from a certain region will demonstrate if commonality of distribution pattern
occurs. If it does occur, the individual tracks will coincide to from a single pathway of massed
tracks. This pathway, or generalized track, may be straight, curved, or irregular, but will be
identifiable as a generalized track to the extent that all of its components share the same
boundaries.”

Tracks therefore join sister-groups and, theoretically, span geographical areas which, at
some past time, have undergone drastic geological and/or biological modification. Plotting
tracks is hindered by extensive areas of sympatry displayed by putative sister-groups. By
vicariance theory, sympatry of sister-species and/or groups indicates dispersal following a
vicariant event. Dispersal, therefore, obscures locations of past vicariant events. Because of
dispersal in Western Hemisphere Hydraenidae, I have elected to illustrate geographical
sister-group relationships in a slightly different way.

As mentioned at various points in the previous section detailing phylogenies, geographical
relationships of certain sister-groups within Western Hemisphere Hydraenidae are repetitive.
That is, some geographical vicariance zones are indicated by more than one sister-group
relationship. Some lineages within a genus and/or different genera indicate the same vicariance
zone.

A vicariance zone is no more than the geographical area separating sister-groups, and
therefore corresponds to the “middle” of individual or generalized tracks.

Validity of a proposed vicariance zone might logically be measured by number of

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sister-groups separated by that geographical area. Further, an estimation of faunal composition
for a given geographical region in the past, and relative ages of phylogenetic dichotomies can be
inferred for the sister-group pairs ( synvicariads^. ) of a vicariance zone.

Figure 188 A is a summary of the vicariance zones inferred from phylogenies and
generalized distributions of hydraenid beetles presented in Figs. 162-187. Arrows in Fig. 188 A
indicate locations of sister-group elements separated by a given vicariance zone. For example,
Vicariance Zone 7 is inferred from the two synvicariads Hydraena exilipes-campbelli
(Fig. 167) and Hydraena pulsatrix-longicollis (Fig. 172B).

The number of sister-groups supporting these vicariance zones varies from one to eight.
Most North and Central American vicariance zones are represented by two or more
synvicariads, whereas all vicariance zones proposed for South America, except one, are at
present supported by only a single sister-group. The lack of synvicariads for South American
zones may be real or a result of inadequate sampling. Indeed, some of the vicariance zones
indicated by present species ranges may be significantly modified when additional distribution
data are obtained for South America. Certainly additional vicariance zones will be identified in
South America as the fauna is better sampled. Less modification of proposed Central American
vicariance zones is anticipated, and very little change for North American zones.

Phylogenies and geographical distributions supporting the vicariance zones of Fig. 188A are
as follows (numbers of Figures in parentheses): 1 (164B, 165A,B, 172B, 175, 178,179,186). 2
(164 A, 175, 181A, 183). 3 (165A). 4(180). 5 (175,180, 185A.B, 187A). 6 (165B,167, 168). 7
(167, 172B), 8 (169, 174, 187B). 9 (169, 171A, 174, 187B). 10 (170, 171A, 173, 175). 11(173,
178). 12 (173). 13 (170). sl4 (172A). 15 (172B). 16 (171B). 17 (171B, 177). 18 (167). 19
(176A). 20 (176A). 21 (168). 22 (162). 23 (162). 24 (167).

These vicariance zones of hydraenid beetles need not coincide with those of other groups, as
vagility and responses to environmental change vary from group to group. As Rosen (1978)
puts it, “..a vicariant event separating two once-connected streams will affect the fishes and
aquatic invertebrates, but not necessarily the birds that feed on them.”

Do these vicariance zones correspond to known paleogeological events? Some North and
Central American vicariance zones seem to relate to Cretaceous and Cenozoic geological events
which will be discussed below. Most vicariance zones proposed for Central America, and all of
those proposed for South America are considered highly provisional; no attempts will be made
herein to relate them to past geologic events or to vicariance patterns of other organisms. They
will serve at this time, however, as part of the growing data base of vicariance theory.

Vicariance Zone 1. - (Fig. 188 A) This corresponds in general location to a shallow sea
which covered part of North America during the late Mesozoic and into early Cenozoic times.
At its maximum transgression in mid-Cretaceous time the Epicontinental Seaway extended
from the Gulf Coast to the Arctic and from Minnesota to western Wyoming. At this same time
(ca. 100 MYBP) sea water flooded about one-third of the present land area of the earth (but
not eastern and western mountains of North America). By the end of the Cretaceous the
Epicontinental Seaway had retreated to the present Plains region. Contraction continued into
early Cenozoic time until the waters parted and drained completely from the craton both
northward and southward (Dott and Batten, 1976). From the geologist’s point of view, “the
Cretaceous flood affected North America profoundly” (Dott and Batten, 1976:362).

Rosen (1975, 1978) suggests that this Epicontinental Seaway (“Cannonball Seaway” in
1978 paper) acted as a vicariant event “that affects the North American and encroaching
southern elements in the Gulf coastal region of North America” (1975:453). Rosen (1978)

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473

O- MID-CRETACEOUS
A- PLIOCENE

A MEXICANUS
B BROWN I

C RETICULOCOSTUS
D APACHE
E AP I CALI S

Fig. 187A-B. (A) Generalized geographical distributions and proposed phylogeny of the similis and cribrieollis Subgroups
of O. ( Asiobates ). (B) Generalized geographical distributions and proposed phylogeny of the reticulocostus Subgroup of
O. ( Asiobates ).

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Figs. 188A-B. (A) Vicariance Zones of Western Hemisphere Hydraenidae (arrows indicate location of sister-groups). (B)
Zones of endemism.

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475

illustrates this with examples of freshwater fishes, salamanders, snakes, an owl, a squirrel, and
mesophytic trees and shrubs. Platnick (1976) suggests the Epicontinental Seaway acted as a
vicariant event for the Holarctic spider genus Callilepis, and that it serves as an explanation for
distributions of monophyletic groups with species in North America, Europe and Asia. Cox
(1974) states that the Epicontinental Seaway and Turgai Straits acted together to divide
Laurasia into two land areas with distinct dinosaur faunas: “Asiamerica” (Asia plus western
North America) and “Euramerica” (Europe plus eastern North America) (see also Platnick,
1976).

This vicariance zone is suggested by eight different dichotomies in four genera of hydraenid
beetles (see above), including both temperate and tropical groups.

Although the location of this vicariance zone corresponds to that of the Epicontinental
Seaway, I do not dismiss the possibility that Pleistocene glaciation and this zone may be
causually related. Some northern species of Hydraena might very well be candidates for
Pleistocene-induced speciation. Stocks of the circulata Group of Hydraena probably existed as
two monophyletic lineages across North America (more precisely, what was to become North
America) before flooding formed the Epicontinental Seaway. The seaway then probably
divided each group to form the ancestors of the four Complexes existing today (Figure 163C -
note that the most recent dichotomies have an eastern and a western component). What leads
me to suspect that Pleistocene glaciations are involved in more recent dichotomies is the fact
that two eastern groups ( angulicollis and pennsylvanica Complexes - Figures 164B, 165B) and
one western group ( atlantica Complex - Figure 165 A) each have one or two species in the
opposite area. Therefore it seems reasonable that preceding the Pleistocene the ancestor of H.
nigra-^angulicollis-appalachicola (Fig. 164B) dispersed westward and that concurrently the
ancestor of H. pacifica-atlantica (Figure 165 A) dispersed eastward. Likewise, westward range
expansion of the pennsylvanica Complex stem species (Figure 165B) probably occurred.
Pleistocene glaciation then split these stem species to form the following sister-groups: H.
pacifica (western) and H. atlantica (eastern); H. nigra (western) and H.
angulicollis-appalachicola (eastern); H. vandykei-sierra (western) and H.
pennsylvanica-ancylis (eastern). Dispersal abilities/propensities of extant species in these
groups are illustrated by H. pennsylvanica (Figure 165B) and, especially, H. angulicollis
(Figure 164B), which now inhabit previously glaciated regions.

The genus Limnebius would appear to be another example where Pleistocene glaciation
more adequately explains the synvicariads of Vicariance Zone 1. Western Hemisphere species
of this genus occupy three geographical areas (Fig. 175): far western (five species) and eastern
(three species) North America, and Central America (eight species). The reconstructed
phylogeny indicates that eastern species have their sister-groups among the western North
American component, not the Central American component. Therefore the major dichotomy of
the genus does not correspond to Vicariance Zone 1, but to Vicariance Zone 5 (see below for a
discussion of that zone).

Is it likely that Limnebius spread northward from Central America? I doubt this since the
genus is primarily temperate, displaying a Laurasian distribution pattern (absent from South
America and Australia).

I surmise, consequently, that sometime after recession of the Epicontinental Seaway, two
western species spread across North America and their ranges were subsequently divided by
Pleistocene glaciation to form the western-eastern sister-group relationships now seen.

If one is to disagree with this hypothesis and claim that eastern species result from the

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Epicontinental Seaway, then Vicariance Zone 5 must be thought to antedate the Epicontinental
Seaway or the phylogeny as proposed thought incorrect (or both).

For example, one could postulate a single wide-spread ancestral species (found in portions of
western, eastern and southern areas of the present day range of the genus) which was vicariated
sequentially by the Epicontinental Seaway (to form an eastern and a western-southern
sister-group relationship), and by a vicariant event in vicariance zone 5 (to form the western
and southern sister-groups). If this sequence of events is correct, however, not only the major
dichotomy of the proposed phylogeny must be spurious, but also the sister-group relationships
of the eastern species.

If one were to accept the phylogeny as proposed, while maintaining that eastern species were
causally related to the Epicontinental Seaway, then Vicariance Zone 5 must be assumed to
have preceded the seaway. Further, two stem species (each with ranges spanning Vicariance
Zone 1) must be postulated to result in the sister-group relationships proposed for eastern
species.

In partial summary, it appears that temperate sister-groups of Vicariance Zone 1 may be
due either to the Epicontinental Seaway or Pleistocene glaciation, but the much older vicariant
event is reflected (in reconstructed phylogenies) at the species complex level (at least in
temperate Hydraena ), whereas the recent vicariant event is reflected in species-level
dichotomies (at least for temperate Hydraena and Limnebius).

Contrastingly, however, components of primarily tropical hydraenid lineages with
sister-group elements on either side of Vicariance Zone 1 appear to be causually related to the
Epicontinental Seaway at the sister-species or sister-species pair level.

Rosen (1975, 1978) has shown that sister-groups of several types of organisms have one
component in the eastern United States, and the other in northeastern Mexico (i.e., on either
side of the southern end of Vicariance Zone 1, Fig. 188 A). Sister-groups of two tropical
lineages of Hydraena also display this pattern (Figs. 167, 172B). These two synvicariads differ
in that one involves primarily montane species whereas the other is composed of lowland coastal
species. The montane species-group (Fig. 167) consists of the sister-species H. ozarkensis
(Ozark Plateau) and H. maureenae (Appalachians), plus the sister-species H. exilipes-H.
campbelli (highlands of eastern and southern Mexico). The lowland coastal species-group
(Fig. 172B) is H. marginicollis in southeastern United States and H. pulsatrix-H. longicollis
in eastern Mexico and Guatemala.

Two other examples of tropical synvicariads of Vicariance Zone 1 are seen in the genus
Gymnochthebius. As discussed elsewhere herein, Gymnochthebius is a Gondwanian genus with
less derived species in temperate South America and more derived species in Central and North
America (the genus is also in Australia). Sister-species of Gymnochthebius which could be
considered zone 1 synvicariads are G. nitidus-G. falli (Fig. 179) and G. oppositus-G. seminole
(Fig. 94 A - seminole is known only from Everglades, Florida). Both of these dichotomies could
be considered causally related to the Epicontinental Seaway and therefore dating from the
mid-Cretaceous.

In short, it appears that Vicariance Zone 1 is a result of both mid-Cretaceous
(Epicontinental Seaway) and Pleistocene (glaciation) geologic events. Within the temperate
circulata Group of Hydraena the much older geologic event (Epicontinental Seaway - ca. 100
million year ago) is reflected in dichotomies at the species complex level, whereas the very
recent geologic event (Pleistocene glaciations - ca. 0.6 million years ago) is reflected in some
species level dichotomies. Likewise, some sister-species and species-groups of temperate

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477

Limnebius appear more likely a result of Pleistocene glaciations than Paleocene flooding.
Nearctic components of primarily tropical lineages, however (e.g., marginicollis and leechi
Groups of Hydraena, and nitidus Group of Gymnochthebius) , which are found in eastern
North America frequently display dichotomies which are probably causually related to the
Epicontinental Seaway.

A vicariance zone, especially one as extensive in size and latitudinal coverage as Vicariance
Zone 1, can therefore be a composite of vicariance events and reflect different dichotomy levels
in reconstructed phytogenies of different groups.

Vicariance Zone 2. - This zone in western North America (Fig. 188 A) coincides in general
location to the “Basaltic Plateau” formed by giant lava flows which began during the Oligocene
and continued locally into Pleistocene times. These lava flows spread out rapidly over large
areas, exceeding 300,000 square kilometers, and filling in valleys (Dott and Batten, 1976). It
seems safe to assume that these extensive lava flows would have extirpated any organisms in
that region (certainly hydraenid beetles), and that resulting disjunction of biological ranges
would have been of lengthy duration.

Five sister-groups of hydraenid beetles support this region as a vicariance zone, including
two in the circulata Group of Hydraena (Fig. 164A), one in Limnebius (Fig. 175) and two in
Ochthebius (Figs. 181 A, 183). Post-vicariance dispersal partially obscures patterns in some of
these examples. Dichotomies causually related to the Basaltic Plateau vicariant event would
date to late Oligocene or Miocene, perhaps about 20-25 million years ago.

As an addendum to discussion of Zone 2, I wish to point out the high degree of sympatry
displayed by species of the discretus Subgroup of Ochthebius in zone 2 (Fig. 186). If one were
to accept the notion that “vicariance underlies and antedates nearly all cases of sympatric
distributions” (Croizat et al., 1974:278), then certainly this lineage could be added to the list of
synvicariads for zone 2. Also, does it possibly betray an error in the proposed phylogeny?

Vicariance Zones 3 and 4. - These zones amongst the California Coast Ranges may well
relate to Miocene marine flooding of the California region. During this time the coast range
basins “suffered remarkable ’see-saw’ tectonics - that is, areas depressed in one epoch to receive
thick sediments were upheaved to form ranges in another epoch of time” (Dott and Batten,
1976). Only one hydraenid sister-group relationship is known for each of these zones, which, in
light of the high hydraenid density in California (discussed below) must mean that California
has been an active area of post-vicariance dispersal for many species.

Vicariance Zone 3 is indicated by the sister-species Hydraena calif ornica-petila
(Fig. 165 A), members of a primarily northern lineage. Zone 4 is derived from the sister-group
Ochthebius biincisus-(gruwelli+ arizonicus) (Fig. 180), members of a lineage which has its
greatest diversity in Mexico.

Vicariance Zone 5. - This zone is suggested by six sister-group relationships, one in
Limnebius (Fig. 175) and five in Ochthebius (Figs. 180, 185A,B, 187A).

Generally speaking, this zone equates to portions of the present arid region of the
southwestern United States. Synvicariads of this zone have their northern components in the
coastal ranges of California or, rarely, in northern Arizona (but apparently not the Rocky
Mountains) southern components are in the Sierra Madre Occidental (including mountains of
southeastern Arizona) or, rarely, the Rio Grande drainage basin.

What paleogeological events could account for this vicariance zone? Data suggest that two,
and possibly three major geological changes have occurred in this region, including a
mid-Cretaceous, a late Cenozoic and a Pleistocene event.

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Dott and Batten (1976:358) depict this region (and areas to the south) as inundated with sea
water during mid-Cretaceous. Rosen (1978:171) illustrates the entire region as exposed during
“Cretaceous-Pleistocene” times, and depicts the western margin of the Epicontinental Seaway
(“Cannonball Seaway”) as east of Vicariance Zone 5 (i.e., passing through what is now Texas,
but not extending westward into present Arizona). Dott and Batten (1976:357), however,
depict mid-Cretaceous sediments of zone 5 as contiguous with those of the Epicontinental
Seaway, consisting of shale and carbonate rocks. Based on this latter evidence, it seems highly
likely that Vicariance Zone 5 was flooded with sea water from the Epicontinental, Seaway.

For this flooding to act as a vicariant event, however, exposed land must have existed
northwest (i.e., present California) and south (i.e., southern Arizona or northern Mexico) of
this region. Dott and Batten (1976:355) state that during late Jurassic times (i.e., long before
mid-Cretaceous flooding) “lands were beginning to be raised in the Cordillera, especially in
western Arizona”, and with respect to the western coastal regions: “The culminating
Cordilleran Orogeny spanned Late Jurassic through early Cenozoic time” (p. 355) and “Along
the western margin of the Cordilleran tectonic land, the Cretaceous shoreline oscillated
somewhat, but effects were less pronounced than on the cratonic side. The western coastline
was steeper...” (p. 362).

It therefore appears likely that, at a time just prior to flooding of Vicariance Zone 5 by the
Epicontinental Seaway, a species could have ranged from the western montane region, through
zone 5 and southward into montane regions of southern Arizona and northern Mexico.

A second geological upheaval occurred in the region of Vicariance Zone 5 during the Late
Cenozoic (about 80 million years after the Epicontinental Seaway - 20 MYBP). During that
time structural changes disrupted drainage systems and caused tremendous volcanic activity,
including extensive lava flows. According to Dott and Batten (1976:389), “Renewed structural
disturbances began in middle Cenozoic time in the central Cordilleral region, as in the Rocky
Mountains, and have continued to the present. But here they were much more severe, involving
chiefly block faulting. In Nevada, southeastern California, western Utah, southern Arizona,
and adjacent Mexico, parallel northerly trending faults produced alternating narrow ranges
and valleys... Faulting provided paths of escape of magma from the bowels of the crust and
mantle. Flows spread over downfaulted valleys and lapped against ranges. Erosion of ranges
produced sediments that also were dumped into the valleys. Renewed faulting offset the lavas
and sediments, and new volcanic outpourings then burried older, faulted rocks”.

Such monstrous Miocene volcanic activity probably could have acted as a vicariant event for
hydraenid beetles.

A third possible geological vicariant event in Vicariance Zone 5 might have occurred during
Pleistocene times as the arid zone begun in the Miocene increased in size until at maximum
glacial advance it extended over much of California, Nevada, Utah and southern Idaho in the
United States, and south to the volcanic plateau in Mexico. “Striking shifts of plant
communities in arid southwestern United States and Mexico (begun in the Miocene) continued
into Pleistocene time” (Dott and Batten, 1976).

The effect of Pleistocene drying upon aquatic organisms with rather limited dispersal
capabilities such as hydraenid beetles may have been principally to “reinforce” disjunction
already formed by Miocene volcanics. However, if hydraenid species extended their ranges into
(and through) zone 5 after the violent Miocene volcanics, say perhaps in mid-Pliocene, they
may have undergone disjunction as a result of Pleistocene hot, dry climatic conditions.

I suspect that Pleistocene-induced disjunctions had very little effect on hydraenid

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479

sister-group relationships for the following reasons. First, recent studies (e.g., Coope, 1967;
Ashworth, 1973a) have shown that periods of glacial recession were quite frequent during the
Pleistocene, and that entire beetle faunal assemblages were able to follow the “ebb and flow” of
ice sheets. Secondly, many hydraenid species now inhabit the arid southwest, in regions which
have adequate physical relief to form permanent streams. It seems likely to me that runnoff
from ice caps on mountains in zone 5 would have produced adequate streams to support most
hydraenid species adapted for arid habitats, and that these species followed the ebb and flow of
the ice caps much as did beetle faunal assemblages near glaciated regions of the northern
United States and Europe. Pleistocene effects on species in Vicariance Zone 5 were, therefore,
probably much less pronounced than those resulting from Miocene volcanics or mid-Cretaceous
flooding.

The decision must now be made as to which of the three postulated vicariant events are
causually related to which hydraenid dichotomies. Of the six sister-groups which show
disjunctions in zone 5, three are major dichotomies of their respective lineages, three represent
more “apical” dichotomies of their respective lineages, and all involve two Laurasian genera.

Interestingly, only one lineage displays two phylogenetically distant dichotomies as related
to Vicariance Zone 5 ( Limnebius , the first dichotomy of the genus plus that of L.
texanus-(richmondi + borealis + arenicolus), Fig. 175), and only one lineage shows notable
sympatry in zone 5 (the biincisus Group of Ochthebius, Fig. 180).

Although the following is more arbitrary than one might wish, based upon the “basal”
nature of three dichotomies, they are tentatively placed at a mid-Cretaceous origin (vicariant
event = Epicontinental Seaway). These dichotomies include: Limnebius , the first dichotomy
(Fig. 175); Ochthebius, discretus Subgroup -reticulocostus Subgroup, and cribricollis
Suhgroup-similis Subgroup (Figs. 185B, 186, 187A,B).

The three “apical” dichotomies are placed at a more recent, Miocene origin (vicariant
event = volcanics). These dichotomies include: Limnebius , sister-group L.

texanus-(richmondi~\- borealis + arenicolus) (Fig. 175); Ochthebius , sister-species O.

puncticollis-angularidus (Fig. 185A), and sister-group O. mexcavatus -

(gruwelli+ arizonicus+ biincisus) (Fig. 180). Only one dichotomy, not yet discussed, is
tentatively attributed to Pleistocene aridity: Ochthebius gruwelli-arizonicus (Fig. 180).

Vicariance Zone 6. - This zone in eastern North America is supported by three synvicariads
in the genus Hydraena, one of temperate and two of tropical lineage. The limits of this zone are
not clearly defined. Synvicariads of tropical lineage include a montane and a lowland coastal
sister-species pair; the montane pair with one species in the Ozarks and its sister-species in the
Appalachians ( H . ozarkensis-maureenae, Fig. 167); the lowland coastal pair with one species
widely distributed from Texas to Florida and north to Maryland, and its sister-species
restricted to New England states ( H . spangleri-punctata. Fig. 168). The third sister-species
pair are members of the temperate circulata Group of Hydraena ( H . pennsylvanica-ancylis.
Fig. 165B).

At present I am unable to definitely associate this vicariance zone with a paleogeological
event, but suspect it relates to Pleistocene glaciation, for the temperate H.
pennsylvanica-ancylis sister-species pair at least. As indicated for other vicariance zones, zone
6 may be a composite of paleogeological events. Dichotomies of the tropical lineages may be
due to early geological events in this region, or to Pleistocene glaciation.

Vicariance Zone 7. - This zone along the gulf coast of Mexico is derived from two
sister-species pairs of tropical Hydraena lineages (H. exilipes-campbelli, Fig. 167; H.

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Perkins

pulsatrix-\ongico\\is, Fig. 172B). Rosen (1978) has very nicely documented examples of
sister-groups which show geographical disjunction in this region, including fresh water fish and
various plants. Rosen (1978:171) depicts this geographical region as being flooded during
mid-Cretaceous times, a position I believe is corroborated by these two hydraenid sister-groups.

Vicariance Zone 8. - This zone corresponds closely in geographical location to a belt of
volcanism which extended across Mexico during Plio-Pleistocene times (Rosen, 1978:171; Dott
and Batten, 1976:430). Hydraenid synvicariads of this zone include two in Spanglerina and one
each in Hydraena and Ochthebius. They are: S. brevis-frondsicola and S. ingens- fluvicola
(Fig. 174); H. argutipes-prieto (Fig. 169); and O. apache-( sister-group) (Fig. 187B). These
dichotomies are therefore postulated to have occurred during Pliocene times.

Vicariance Zone 13. - This zone (between Cuba and Haiti-Dominican Republic) is
suggested by one sister-group of Hydraena , H. perkinsi-haitensis (Fig. 170). However, more
complicated patterns of distribution in this region are seen in the particeps Subgroup of
Hydraena (Fig. 168). These sister-group patterns have been discussed earlier in the section on
that Subgroup; they may relate to Rosen’s (1975) vicariance model of Caribbean biogeography.

Endemism

As a conclusion to this preliminary study of hydraenid zoogeography, I have divided the
Western Hemisphere into geographical regions (Fig. 188B) and compiled, for each region, (1)
the total number of species and (2) the number restricted to that region (i.e., endemics). Region
2 for example, which consists almost entirely of California, has 45 hydraenid species, 17 of
which are restricted to that region.

The primary goal in delineating these regions is to identify and contrast areas high in
endemics from those with depauperate faunas. Most of the boundaries selected coincide with
vicariance zones (cf. Figs. 188A,B), which is not mysterious since vicariance zones are
measures of sister-group allopatry as are zones of endemism. Some of these areas correspond
generally to geological regions, such as the Great Basin (4), Rocky Mountains (6) and Great
Plains (7); others, such as the Antilles (21) may be more arbitrary.

The number of species per region are as follows (endemics/total):

I (1/28). 2 (17/45). 3 (0/4). 4 (0/10). 5 (0/5).

6 (3/26). 7 (0/5). 8 (3/19). 9 (0/1). 10 (2/14).

II (3/12). 12 (12/24). 13 (14/22). 14 (0/4). 15 (0/3).

16 (6/13). 17 (5/16). 18 (3/14). 19 (4/10). 20 (3/6).

21 (5/9). 22 (1/4). 23 (1/7). 24 (8/9). 25 (0/3).

26 (1/1). 27 (3/5). 28 (14/14). 29 (1/1). 30 (1/3).

31 (2/3). 32 (1/1). 33 (7/7). 34 (0/0). 35 (1/1).

36(1/1).

Since most hydraenid species live in montane streams, it is not unexpected that montane
geographical regions 2 (California-45 species, 17 endemic) and 6 (Rocky Mountains-29
species, 3 endemic) have more species than arid, flat areas such as regions 4 (Great Basin- 10
species, no endemics) and 7 (Great Plains-5 species, no endemics). Why, however, do species
totals and endemism percentages differ greatly between montane regions 2 (45 species, 38%
endemic) and 6 (29 species, 12% endemic)?

The number of species in each geographical region is a product of the number of vicariant
events within and at the borders of that region, plus the extent of dispersal into that region.
Dispersal in turn is dependent upon vagility and habitat availability (the latter including

Western Hemisphere Hydraenidae

481

competition factors), Vor a given geographical region, the percentage of endemics is higher
when border vicariance zones are not crossed by synvicariads, and lower when post-vicariance is
common.

As Fig. 188A shows, California has been a region of extensive, demonstrable vicariance
activity. The Rocky Mountains, however, show fewer vicariant events (only one in hydraenids,
but other vicariant events probably occurred and have been subsequently obscured by
dispersal). Additionally, dispersal east and south from (and into) California has been greatly
curtailed by desert conditions since the Miocene, which results in a higher percentage of
endemism. However, post-Miocene dispersal of California species northward into the Rocky
Mountains of British Columbia, and then southward in the Rockies has been rather
commonplace, as has dispersal in the opposite direction by Rocky Mountain species (see
Figs. 164A,B, 165A, 175, 186).

EPILOGUE

In this paper I have attempted to elucidate, as clearly as possible, the individual building
blocks of hydraenid systematic studies: species taxa. I have also attempted to define the major
evolutionary lines of the family, based upon synapotypic character states. These tasks remain,
however, far from complete.

Phylogenetic relationships of the most dissimilar genera are now fairly well established.
However, this reconstructed phylogeny is only a preliminary framework to be tested and built
upon as new genera, most likely South African and Australian, are discovered and described.
Some of the putative synapotypic character states I have used, especially those of the larvae,
are based only on simple similarity. Much work remains to establish, particularly by out-group
comparisons, morphocline polarities and to differentiate apotypic from plesiotypic character
states.

Especially within the species-complex do we find difficulty in supporting suggested
phylogenies. Many of the sister-species pairs proposed herein are based upon aedeagal
similarity. Certainly some of these species have been correctly paired, and we can credit the
complex male genitalia for this small success. But again, certainly some of these putative pairs
are incorrect, and errors in the phylogenies lead to more of the same in the biogeographical
analysis, since correct historical biogeography is contingent upon strict monophyly.

Cladistics and vicariance methods rely entirely upon adequate material, the field-work
foundation of all systematic studies. Much specialized collecting remains to be done in Central
and especially South America. Certainly there are many undiscovered forms in the neotropics
which, when carefully studied, will modify the reconstructed phylogenies and distributions, and
alter the very preliminary vicariance zones which are indicated by specimens presently
available.

We cannot know for certain the percentage of error in the reconstructed, species-level
phylogenies, but the repetitiveness of sister-group patterns does suggest some degree of
correctness, that is if vicariance theory is accepted. That is to say, repetitiveness of disjunction
areas between sister-groups is what one would expect to find if reconstructed phylogenies are
correct.

Of course we must avoid the circular argument of using vicariance theory to explain
sister-group distributions and concurrently using coincident sister-group patterns as evidence
that vicariance has occurred. In this work the reconstructed phylogenies are based solely upon

Quaest. Ent., 1980, 16 (1,2)

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Perkins

morphology. Only after the phytogenies were reconstructed did I search for sister-group
coincidence. Finally, as a last step, I searched the literature for paleogeological events to
correlate with these geographical areas of sister-group disjunction. To my pleasant surprise, in
nearly every instance, the “vicariance zones” established for hydraenids in North America and
northern Central America had a geographical coincidence with a major paleogeological event,
either flooding, volcanism or glaciation. Now, in retrospect, I have more confidence in the
phytogenies than had I not used them in a biogeographic analysis.

APPENDIX A: PARATYPES AND SPECIMENS EXAMINED

(Depository abbreviations in parentheses are accompanied by the number of specimens
studied. When two numerical entries are given, separated by a diagonal line, males are
represented by the first entry, females by the second. Genera are given in this sequence:
Parhydraenida, Hydraena, Limnebius, Gymnochthebius, Ochthebius, and Neochthebius.
Dates are given in a year-month-day sequence. Species which have all of their locality data
cited in the text are not included in this appendix).

1 . Parhydraenida reichardti J. Balfour- Browne

Map: Figure 14B
Specimens examined: 16

Brazil: Espirito Santo: 18 km E. Itabita, 900 m (km 138, Br 262), 75-02-07, H. & B. Reichardt (0/1 MSP). Rio de
Janeiro: Teresopolis, km. 17, 1180 m., hygropetric habitat, 77-04-19, S. Vanin & O. Flint (2/1 MSP; 1/0 USNM; 1/1
PDP). Santa Catarina: Blumenau, cascata-Estrada, junto Rio Garcia, 75-12-02, Froehlich & Vanin (2/1 MSP; 1/0
USNM; 1/0 PDP). Sao Paulo: Salesopolis, Reserva Casa Grande (Pedreira), hygropetric habitat, 77-10-03, Froehlich &
Chapon (1/0 MSP). Sao Sabastiao, 15 km. S., 71-10-03, FI. & B. Reichardt (1 MSP). Salesopolis, Est. Biol. Boraceia,
71-09-24, H. & B. Reichardt (1 MSP).

1 . Hydraena eirculata new species

Map: Figure 23A
Paratypes: 790

Canada: Alberta: Edmonton, 20-05-19, F.S. Carr (0/1 MCZ). British Columbia: Victoria, Vancouver Is., no date,
Wickham (0/1 USNM). Cariboo Dist., Beedy Creek at Gaston Ranch, 30 mi. NE McLeese Lake, 71-07-25, P.D. Perkins
(1/6 PDP). Fraser Valley, no date, no collr. (0/1 USNM). Ashcroft Manor, irrigation ditch, 40-05-30, H.B. Leech (0/2
CAS). Tappen, White Lake Creek, 33-10-09, H.B. Leech (5/12 CAS). Summerland, 32-06-09, A.N. Gartrell (1/0
CNC). Kitchener, Goat River, 51-08-26, G. Stace Smith (9/6 UBC). As above, 55-09-04 (0/2 UBC). Sanca, Sanca
Creek, 33-04-23, G. Stace Smith (1/0 UBC). 20 mi. W. Rossland, bog, 69-09-23, J. Schuh (0/1 JS). Fraser Valley, no
date, no collr. (1/0 USNM). Peachland, 15-08-23, J.B. Wallis (0/1 CNC). Kamloops, Lac du Bois swamp, no date, H.B.
Leech (1/1 CAS). Jaffray, Little Sand Cr., 50-07-23, H.B. Leech (0/1 CAS). Lumby, 37-09-19, H.B. Leech (0/2 CAS).
Terrace, no date, M.E. Hippisley (0/1 CAS). Edgewood, Inonoaklin River, 46-09-29, S.H. Farris (0/1 CAS).

Mexico: Baja California: La Suerte, Sierra San Pedro Martir, pool in canyon, 3700’, 63-06-04, R.K. Benjamin (0/1
CAS).

United States: Arizona: Cochise Co.: Upper Carr Cyn., Huachuca Mts., 7500’, 52-08-06, H.B. Leech (0/1 CAS).
Sunnyside Cyn., W. side Huachuca Mts., 52-08-04, H.B. Leech (0/1 CAS). Chiricahua Mts., above Herb Martyr,
74-06-22, Harley P. Brown (1/0 HPB). Coconino Co.: Oak Cr. Canyon Midgley Bridge, 52-07-25, H.B. Leech (1/0
CAS). Pima Co.: Santa Catalina Mts., 46-06-01, Bryant (0/1 CAS). S. Catalina Mts., 5000’ no date, no collr. (1/1 CU).
Pinal Co.: Riverside no date, Wickham (0/1 USNM; 1/0 CAS). Santa Cruz Co.: Madera Cyn., Santa Rita Mts.,
52-08-01, H.B. Leech (4/3 CAS). Yavapai Co.: Brush Cyn., Bloody Basin, 74-06-19, H.P. Brown (1/0 HPB). California:
Alameda Co.: Dublin, 47-07-20, P. Giuliani (0/1 CAS). Dimond, 60-05-15, F.E. Blaisdell (0/2 CAS). Butte Co.: 1 mi. E.
Paradise, 1650’, 70-11-26, P.D. Perkins (1/1 PDP). Little Chico Creek at School Rd., E. of Forest Ranch, Alt. 2300',
61-09-01, H.B. Leech (15/12 CAS). French Creek, 49-06-23, H.P. Chandler (3/0 CAS). Calaveras Co.: 4.5 mi. W.
Altaville, Waterman Cr., 63-08-31, H.B. Leech (0/1 CAS). Murphys, 2500’, 36-05-19, F.E. Blaisdell (1/0 CAS).
Mokelumne Hill, 07-08-06, F.E. Blaisdell (0/3 CAS). Contra Costa Co.: Perkins Gulch, 7 mi. SE Clayton, 66-07-22, J.

Western Hemisphere Hydraenidae

483

Doyen (2/1 UCB). El Dorado Co.: Strawberry Valley, 03-09-01, no collr. (0/3 CAS). Rubicon River at
Georgetown-Ralston Rd., 63-07-27, H.B. Leech (0/1 CAS). 2 mi. SSE Quintette, tributary. Whaler Creek, 63-07-27,
H.B. Leech (4/3 CAS). Fresno Co.: Fresno, no date, E.A. Schwarz (0/1 USNM). Fresno, no date, H.T. Scott (2/2
LACM). Fresno, 33-06-01, R. Wagner (38/40 UCD). Taenio, no date, no collr. (1/2 UCB). Stream from E. entering
S. Fr. San Joaquin R. at gauging station by N. end Jackass Dike, N. of Florence Lake, 7200’, 71-08-31, H.B. Leech
(14/7 CAS). Fresno, no date, R. Wagner (2/2 CAS). Humboldt Co.: Mad R. at Kneeland-Addison road, 66-08-09,
H.B. Leech (0/1 CAS). Hydesville, no date, no collr. (1/0 CAS). 0.8 mi. W. Butte Cr., pool in drying up stream under
Route 36, Larabee Valley, Alt. 2470’, 68-07-19, H.B. Leech (0/2 CAS). Inyo Co.: Bartlett Sprs., no date, no collr. (0/1
MCZ). Kern Co.: Cedar Cr., just above Alder Cr. campground, Greenhorn Mts., 4000’, 70-03-24, H.B. Leech (0/1
CAS). Alder Creek, Alder Creek Campground, 4000’, W. side Greenhorn Mts., 70-03-24, H.B. Leech (2/0 CAS).
Lake Co.: L. Blue Lake, 47-08-11, 1500’, 47-08-11, H.P. Chandler (0/1 CAS). Bartlett Creek, Bartlett Springs,
55-080-1, H.B. Leech (0/1 CAS). Lucerne, fool pool, dried bed of Cottage City creek, 55-08-30, H.B. Leech (0/1
CAS). 6.9 mi. N. Middletown on Hway. 29, puddle in grassy slope, R.A. Badger Ranch, 55-02-07, J.R. Heifer (14.3
CAS). 6.9 mi. N. Middletown on Hway 29, R.A. Badger Ranch, ephemeral stream, 55-02-20, H.B. Leech (0/3 CAS).
Los Angeles Co.: Pasadena, 18-1 1-02, J.O. Martin (1/0 Cas). Los Angeles, no date, A. Koebele (0/2 USNM). Mts. nr.
Claremont, no date, no collr. (1/0 CMP). Chatsworth Cyn., 20-04-03, L.L. Muchmore (2/4 LACM). Los Angeles, no
date, Hubbard and Schwarz (1/0 USNM). Los Angeles, no date, no collr. (1/0 USNM). Pasadena, 18-02-09, J.O.
Martin (0/1 CAS). No site, no date, no collr. (1/0 USNM). Madera Co.: Boggy Mdws., 6000’, 46-07-15, H.P.
Chandler (0/1 CAS). Whiskey Creek, 4000’, H. Dietrich (2/0 CU). Northfork, 29-03-19, H. Dietrich (1/0 CU). As
above, 20-03-07, (7/7 CU). Sugar Pine, no date, A. Fenyes (0/12 CAS). Marin Co.: Lake Lagunitas, 19-04-01 (0/1
CAS). Novato, in stream bed, 52-06-17, H.B. Leech (0/1 CAS). No site, 19-11-08, H. Dietrich (1/0 CU). Mariposa
Co.: Miami Range Sta., 5000’, 42-07-06, H.P. Chandler (1/0 UCB). Sweetwater Creek, 46-07-24, H.P. Chandler (2/0
CAS). Mendocino Co.: Bear Pen Canyon Cr., just above junction with Burger Creek, Dos Rios-Laytonville rd.,
72-08-30, H.B. Leech (0/3 CAS). Mill Cr. just W. of Mailliard Redwoods State Park, 64-09-06, H.B. Leech (0/1
CAS). Black Butte River just above mouth, 68-07-17, H.B. Leech (0/1 CAS). Mendocino, 54-07-17, J.R. Heifer (0/1
CAS). Jumpoff Cr., 53-08-14, P.S. Bartholomew (0/2 CAS). Eel River R.S., 53-08-14, P.S. Bartholomew (0/1 CAS).
Williams Creek at Covelo-Paskenta Rd., 68-07-17, H.B. Leech (0/1 CAS). Bloody Run Creek, 7 mi. E. route 101 on
Longvale-Covelo rd., 1100’, 68-07-18, H.B. Leech (0/3 CAS). Mendocino, 57-07-21, J.R. Heifer (0/1 CAS).
McDowell Cr., just below Oasis, 1800’, 55-07-27, H.B. Leech (1/0 CAS). Modoc Co.: Rush Cr., 9 mi. N. Admin,
50-07-16, H.B. Leech (0/1 CAS). Mono Co.: Round pond on ridge S. of Leavitt Mdw., 63-08-13, H.B. Leech (0/1
CAS). Pond on ridge S. of Leavitt Mdw., 7500’, 62-08-10, H.B. Leech (0/1 CAS). Leavitt Mdw., Ranunculus pool by
West Walker River, 62-08-09, H.B. Leech (0/1 CAS). Monterey Co.: Escondido, 74-09-01, J.E. Cronin (1/0 JEC). As
above, 73-05-19. (2/2 JEC). Jolon, 44-04-08, E. Ray (0/1 CFMNH). Lion Cr., 4.1 mi. NE jet. Hwy. 1 and Kirk Cr.,
71-10-25, P.D. Perkins, (4/8 PDP). As above, 72-06-17 (8/5 PDP). The Indians, seepage trickle over gravelly soil, 2
mi. SE Santa Lucia Memorial Park, 56-01-15, H.B. Leech (7/0 CAS). As above, 56-01-16 (5/4 CAS). The Indians,
seepage over rocks and small cliffs, 56-01-16, H.B. Leech (5/11 CAS). Junipero Serra Pk., Santa Lucia Mts., Forestry
Camp spring, ca 4900’, 56-08-12, H.B. Leech (8/3 CAS). Pleyto Rd. at San Antonio River, 63-04-09, D.C. Rentz and
K.A. Hale (1/0 CAS). Monterey, 16-06-24, J.O. Martin (0/1 CAS). Carmel, 14-06-27, L.S. Slevin (1/0 CAS). Napa
Co.: Pope Cr. at Walter Sprs. road, 520’, 64-08-24, H.B. Leech (0/1 CAS). Pope Cr. at Maxwell Creek, 64-05-10,
H.B. Leech, (0/1 CAS). Calistoga, 34-06-13, Bryant (1/0 CAS). Nevado Co.: Graniteville, 70-07-01, D.S. Chandler
(0/2 UA). Graniteville, 52-08-22, P.S. Bartholomew (3/0 CAS). Sagehen Cr., 70-07-27, D.S. Chandler (1/1 UA). As
above, 70-07-22, (1/0 UA). Placer Co.: No site, no date, A. Koebele, (0/2 USNM). Lake Tahoe, 1879-05-24, no collr.
(0/1 1NHS). Plumas Co.: West Ridge, Portola, 53-05-10, P.S. Bartholomew, (0/1 CAS). Riverside Co.: San Jacinto
Mts., no date, F. E. Winters, (0/2 CAS; 0/2 MCZ). Riverside, no date, F.E. Winters, (0/2 MCZ). San Jacinto Mts.,
no date, F.E. Winters, (14/5 CU). Sacramento Co.: Folsom, 1885-07-05, no collr. (0/1 USNM). San Bernardino Co.:
Lake Arrowhead, 43-05-07, G.P. Mackenzie, (1/3 LACM; 1/0 UCR; 1/3 CAS; 1/2 UA). San Diego Co.: Poway, no
date, F.C. Bowditch (1/1 MCZ). Nr. Warner Hot Sprs., 58-05-07, D. Giuliani (1/0 CAS). San Diego, no date, F.E.
Blaisdell (0/1 CAS). San Francisco Co.: San Francisco, no date, D. Giuliani (0/1 CAS). San Luis Obispo Co.: Santa
Lucia Range, 1800’, 54-07-05, Bryant (1/2 CAS). San Mateo Co.: No site, no date, no collr. (2/3 CAS). San Barbara
Co.: Santa Barbara, no date, F.E. Winters (4/11 CAS). Santa Cruz Island, no date, F.E. Winters (0/1 CAS). Santa
Clara Co.: Guadelupe Creek, 74-06-01, J.E. Cronin (3/4 JEC). Sveadal, 71-05-04, J.E. Cronin (0/2 JEC). Sveadal,
68-04-27, A. and A. Gillogly (1/0 AG). 15 mi. N. Lick, Mt. Hamilton, 68-02-22, A. and A. Gillogly (6/13 AG; 1/0
UCR). 16.5 mi. N. Lick, Mt. Hamilton, 68-03-01, A. and A. Gillogly (0/9 AG). 14 mi. N. Lick, Mt. Hamilton,
68-03-01, A. and A. Gillogly (0/1 AG). 25.6 mi. N. Lick, Mt. Hamilton, 68-03-31, A. and A. Gillogly (1/0 AG).
Stanford Univ., Los Trancos Creek, 51-02-09, P.S. Bartholomew (0/1 CAS). Gilroy, 15-06-07, no collr. (1/0 CAS).
Santa Cruz Co.: Santa Cruz Mts., no date, A. Koebele (2/7 USNM; 1/0 CAS). Shasta Co.: 2.5 mi. W. and S. Viola
Bailey Creek, 61-08-31, H.B. Leech (/3 CAS). Castle Crags St. Park, Silver Slipper Creek, 50-07-29, H.B. Leech (0/1
CAS). Sierra Co.: N. Fork Yuba River above Indian Valley, 61-08-26, H.B. Leech (1/2 CAS). Onion Cr., N. end
Onion Valley, 6075’, 64-10-21, H.B. Leech (2/0 CAS). Siskiyou Co.: N. Russian Creek at foot Jumpoff Joe curve,
Etna road, 3640’, 70-08-17, H.B. Leech (0/1 CAS). Shasta Retreat, no date, no collr. (1/0 CAS). No site, no date, A.
Koebele (0/1 USNM). No site, no date, F.E. Blaisdell (1/0 CAS). Sonoma Co.: Cheney Cr. 2.8 mi. S. and E. of

Quaest. Ent., 1980, 16 (1,2)

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Bodega Bay, 63-07-01, H.B. Leech (0/2 CAS). No site, no date, no collr. (0/1 CAS). Mark West Cr. at Calistoga rd„
ca 4 mi. S. of Petrified Forest, 63-07-08, H.B. Leech (1/0 CAS). Stanislaus Co.: 16 mi. W. Patterson, Adobe Creek,
48-04-25, H.B. Leech (2/0 CAS). Tehama Co.: 1 mi. SW Government Camp, clear mountain stream, 6000’, 60-07-29
(0/1 CAS). S. Fr. Battle Creek, 70-05-16, D.S. Chandler, (1/3 UA). As above, 70-08-09 (1/0 UA). 7.1 mi. W.
Manton, S. Fk. Battle Creek, 61-08-31, H.B. Leech (7/5 CAS). Trinity Co.: Upper Mumbo Lake, NE corner Trinity
Co., 6110’, 68-08-04, H.B. Leech (0/2 CAS). Darlingtonia bog, Scott Mt. Pass, 5300’, 66-08-18, H.B. Leech (0/1
CAS). Van Horn Cr. 1.5 mi. above its mouth at upper Mad river, 2850’, clear water pools in gravel and stones of
otherwise dry and shaded creek, 70-08-09, H.B. Leech (1/1 CAS). Mud Lake, road to Lake Eleanor trail, 1280 m,
72-08-10, H.B. Leech (0/1 CAS). Scott Mtn. summit campground, Callahan-Carville Road, pools, small stream in
drying Darlingtonia bog by camp, 5403’, 70-08-22, H.B. Leech (0/1 CAS). Tulare Co.: Kaweah, no date, Hopping (0/1
USNM). Sequoia N.P., no date, F. T. Scott (1/0 MZ). Kaweah, 44-09-20, no collr. (1/0 CAS). Marble Fork, 7000’,
no collr. (0/2 CAS). Potwisha, 2000’-5000’, 31-07-16, no collr. (2/0 CAS). As above, 3000’-5000', 29-06-02, (6/6
CAS). As above, 7000’-9000’, 29-06-20 (2/3 CAS). 3 km E. California Hot Springs, tributary to Capinero Creek, alt.
1219 m, 69-04-10, H.B. Leech (2/0 CAS). Kaweah, no date, R. Hopping (2/2 CAS). Tuolumne Co.: 1.5 mi. N.
Pinecrest Lake, trib. to Herring Cr., 6000’, ex seepage full of dead conifer leaves, 64-08-08, H.B. Leech (0/1 CAS).
Pinecrest, 47-07-15, P.H. Arnaud, Jr. (1/0 CAS). Sonora, no date, H P. Chandler (1/0 CAS). Colorado: Chaffee Co.:
Buena Vista, no date, no collr. (0/1 MCZ). El Paso Co.: Colorado Springs, 6000’-7000', 1896-Fremont Co.: Coal Creek
Canyon, 30-07-25, J.W. Green (5/4 CAS). Gunnison Co.: W. side of Monarch Pass, 36-07-29, no collr. (0/2 UCM).
Routt Co.: Steamboat Springs, 6800’, 41-10-01, Bryant (3/0 CAS). Unspecified Co.: No site, no date, C. Palm (3/1
AMNH). No site, no date, no collr. (2/4 INHS). Idaho: Adams Co.: 3 mi. W. New Meadows, Mud Creek, 56-07-20,
H.B. Leech (2/0 CAS). Bingham Co.: No site, no date, Hubbard and Schwarz (0/2 USNM). Bonner Co.: Pack River,
50-07-19, H.B. Leech (0/2 CAS). 8 mi. N. Sandpoint, Pack River, 69-09-22, J. Schuh (0/4 JS). Montana: Blaine Co.:
Bear Paw Mt., no date, Hubbard and Schwarz (5/3 USNM). El Paso Co.: Colorado Springs, no date, Hubbard and
Schwarz (1/0 USNM). Lewis and Clark Co.: Helena, no date, Hubbard and Schwarz (2/1 USNM). Unspecified Co.:
Assinbne, no date, Hubbard and Schwarz (2/0 USNM). New Mexico: Catron Co.: 4 mi. NE Glenwood, Whitewater
Canyon, 52-08-20, H.B. Leech (1/0 CAS). Grant Co.: 6 mi. N. Pinos Altos, Cherry Cr. picnic grounds, 52-08-21, H.B.
Leech (0/2 CAS). Sandoval Co.: Jemez Mts. no date, J. Woodgate (1/0 CAS). Jemez Sprs., no date, no collr. (1/2
CU; 6/15 AMNH). Sante Fe Co.: St. Fe. Canyon, no date, no collr. (1/1 CNC). Oregon: Baker Co.: Halfway,
68-07-06, J.L. Carr (3/0 JLC). Benton Co.: 9 mi N. Corvallis, 59-05-02, G. Kraft (1/1 USNM). Curry Co.: Pistol
River, Meyers Cr., 38-05-18, H.B. Leech (0/1 CAS). Douglas Co.: 1.5 mi. E. Tiller, side hill rill, 66-05-31, J. Schuh
(0/1 JS). Grant Co.: Pass Cr. N. of Long Cr., 50-07-18, H.B. Leech (1/0 CAS). Beech Cr., 5015', 50-07-17, H.B.
Leech (0/1 CAS). Ritter Hot Springs, temp. 78-90°F., 62-04-05, K. Goeden (0/1 ODA). Hood River Co.: Hood River,
no date, Hubbard and Schwarz (1/0 USNM). Jackson Co.: 8 mi. S. Hwy. 66 Copco Rd., ex. moss along creek,
61-05-20, J. Schuh (0/1 JS). Klamath Co.: Mare’s Egg Spring, 62-05-30, J. Schuh (2/1 DCM). 8 mi. NE Bly, Deming
Creek, 67-08-19, J. Schuh (1/4 JS). 11 mi. NE Bly, edge Deming Creek, 66-05-13, J. Schuh (2/1 JS). 15 mi. NE Bly,
Deming Creek, J. Schuh (2/0 JS). 11 mi. NE Bly, Deming Creek, 69-09-16, J. Schuh (1/0 JS). 12 mi. NE Bly, Long
Creek, 67-09-24, J. Schuh and E. Evans (0/2 JS). Denny Cr., 58-05-01, J. Schuh (0/1 JS). Upper Klamath Lake,
along lake shore, 55-05-17, J. Schuh (0/1 JS). Klamath Falls, Barkley Springs, 55-06-01, J. Schuh (0/1 JS). 7 mi. NW
Bly, Meryl Cr., 62-05-01, J. Schuh (0/1 JS). Lane Co.: 7mi. S. Florence, Siltcoos Bch., Vertrees, Hansen, Carter and
Schuh, 62-05-01 (0/2 JS). 2 mi. N. Junction City, 72-02-12, L. Ryker (0/1 ORSU). Multnomah Co.: Portland, no
date, Hubbard and Schwarz (0/1 USNM). Umatilla Co.: Fly Cr., 61-11-15, J. Schuh (0/2 JS). Blue Mts., 34-08-12,
Bryant (0/1 CAS). Wheeler Co.: 10 mi. NNE Spray, NE Fk. Deadhorse Cr., 3178’ 64-07-06, H.B. Leech (0/3 CAS).
Utah: Garfield Co.: Canyon City, no date, Hubbard and Schwarz (0/2 USNM). Unitah Co.: Cub River Cyn.,
56-12-04, G.F. Knowlton (2/3 OSU). Wasatch Co.: Provo River, 2 mi. below upper bridge, 48-06-01, G.K. Todd (0/1
INHS). Washington: Pierce Co.: Tacoma, no date, H.F. Wickhan (0/1 USNM). Whatcom Co.: Ross Lake, 71-07-22,
P.D. Perkins (2/0 PDP). Wyoming: Lincoln Co.: Allred Flats Rec. Area, 6700’, 62-06-24, C.W. O’Brien (0/1 UCB).
Sheridan Co.: Bighorn Natl’l. Forest, Isaac Walton picnic area, nr. Dayton, 62-08-14, P. and P.J. Spangler (1/1
USNM).

2. Hydraena arenicola new species

Map: Figure 27D
Paratypes: 433

United States: California: Butte Co.: Little Chico Cr. at School Rd., E. of Forest Ranch, 2300', 61-09-01, H.B.
Leech (1/0 CAS). Contra Costa Co.: Hills back of Oakland, 08-06-07, no collr. (1/2 cas). Berkeley, 19-11-11, H.
Dietrich (1/2 CU). Humboldt Co.: Mad River at Kneeland-Addison Rd., 66-08-09, H.B. Leech (0/1 CAS). Frenchman
Creek at Garberville-Alder Point Rd., 68-07-18, H.B. Leech (2/1 CAS). Larabee Valley, 0.8 mi. W. Butte Cr., pool in
drying up stream under route 36, 2470', 68-07-19, H.B. Leech (4/0 CAS). Conley Creek, 0.8 mi. SE Blocksburg, 1350’,
68-07-19, H.B. Leech (4/5 CAS). Burr Cr., 3 mi. S. of Bridgeville, 1200’, 68-07-19, H. B. Leech (0/5 CAS). Martin
Cr., 10 mi. S. of Bridgeville, 1150’, 68-07-19, H.B. Leech (0/1 CAS). N. Fork Yager Cr. at Bridgeville-Kneeland

Western Hemisphere Hydraenidae

485

Road, 130&’, 66-08-08, H. B. Leech (0/2 CAS). Stream under Blair road at 1950’, 3 mi. airline WSW Hoopa,
70-08-14, H.B. Leech (4/3 CAS). Toss-up Creek, confluence with Redwood Cr., 2.5 mi. N. road to Hoopa, 70-08-13,
H.B Leech (2/4 CAS). Redwood Creek, Redwood Valley, 3 mi. N. of road to Hoopa. 70-08-12, H.B. Leech (0/1
CAS). Lake Co.: Headwaters, Long Valley Creek, 55-08-01, H.B. Leech (3/3 CAS). Lucerne, foul pool, dried bed of
Cottage City Creek, 55-07-30, H.B. Leech (1/0 CAS). Bartlett Creek, Bartlett Springs, 55-08-01, H.B. Leech (2/0
CAS). Lucerne, creek behind Cottage City Resort, 53-07-05, H.B. Leech (1/1 CAS). Kelsey Creek, Kelseyville,

49- 05-29, H.B. Leech (0/1 CAS). 6.9 mi. N. Middletown, R.A. Badger Ranch, ephemeral stream, 55-02-20, H.B.
Leech (21/32 CAS). Bear Cr. at Crabtree Hot Sprs. Rd., 55-08-04, H.B. Leech (1/1 CAS). Rice Fork of Eel River at
Crabtree Hot Sprs., 57-08-09, H.B. Leech (1/3 CAS). 12 mi. N. Upper Lake, 65-03-18, J. Doyen (2/1 UCB). Middle.
Cr., 5 mi. N. Upper Lake, 55-08-04, H.B. Leech (3/2 CAS). Los Angeles Co.: San Gabriel Mts., no date, no collr.
(1/0 CU). Mts. nr. Claremont, no date, no collr. (1/2 CMP). Pomona Mts., no date, no collr. (2/0 MCZ). No site, no
date, no collr. (1/0 USNM). Marin Co.: Mill Valley, 52-04-04, H.B. Leech (0/1 CAS). As above, 52-04-27, (0/1
CAS). Novato, 52-04-17, H.B. Leech (0/1 CAS). Redwood Cr. at Hwy. 1, 71-10-24, P.D. Perkins (1/2 PDP). Carson
Ridge, Woodacre, 56-01-09, H. B. Leech (3/3 CAS). Lake Lagunitas, 19-09-01, no collr. (1/0 CAS). Lagunitas Cr. at
Tocaloma, 68-05-04, H.B. Leech (1/0 CAS). Cypress Ridge, 57-05-16, D. Giuliani (1/0 CAS). Fairfax, no date, F.E.
Blaisell (2/2 CAS). Mill Valley, 57-04-25, H.B. Leech (3/1 CAS). Mill Valley, Cascade Cr., 51-05-09, H.B. Leech
(2/5 CAS). As above, 52-04-04, R.E. Leech (2/6 CAS). Lagunitas Cr. at Tocaloma, 68-05-04, H.B. Leech (1/0 CAS).
Tocaloma, pool at culvert, 68-05-04, H.B. Leech (1/11 CAS). Rock Spring, Mt. Tamalpais, Cataract Creek, 52-05-25,
H.B. Leech (0/1 CAS), no site, 19-11-08, H. Dietrich (1/0 CU). Mendocino Co.: Mendocino, 57-07-21, J R. Heifer
(2/1 CAS). Longvale Cr., 38-07-27, Van Dyke (1/0 CAS). McDowell Cr. just below Oasis, 1800’, 55-07-27, H.B.
Leech (8/6 CAS). McDowell Cr. at foot of grade below Oasis, 1000’, 55-07-27, H.B. Leech (0/2 CAS). Williams Cr.
at Covelo-Paskenta Rd., 68-07-17, H.B. Leech (0/2 CAS). Beebe Cr., 50-09-05, H. B. Leech (1/1 CAS). Twin Rocks,
29-07-10, Van Dyke (5/2 CAS). Parson Cr., 4.5 mi. NE Hopland, 64-06-30, H.B. Leech (4/12 CAS). 1 mi. S. Tatu,
Longvale-Dos Rios Rd., Rodeo Creek, 68-07-17, H.B. Leech (0/1 CAS). Mendocino, 57-07-06, J.R. Heifer (0/1 CAS).
Mill Cr., just W. of Mailliard Redwoods S. P., 64-09-06, H.B. Leech (1/1 CAS). Eel River N. of Potter Valley,

50- 09-02, H.B. Leech (0/1 CAS). Rancheria Cr., 5.5 mi. SE Boonville, 0-06-15, H.B. Leech (7/4 CAS). Rattlesnake
Cr., Cummings, 48-09-14, H.P. Chandler (2/0 CAS). Napa Co.: 6 mi. NE Rutherford, 71-07-16, P.D. Perkins (1/3
PDP). Nevada Co.: Graniteville, 52-08-22, P.S. Bartholomew (1/2 CAS). Riverside Co.: Palm Springs, no date,
Hubbard and Schwarz (1/5 USNM). Santa Barbara Co.: Santa Cruz Island, 70-09-19, P.D. Perkins (3/9 PDP). Santa
Inez Mts., no date, no collr. (1/3 CAS). Clear Creek, Cuyama Cyn., 37-03-07, E. Ross, H.B. Leech & M. Cazier (0/1
CAS). Santa Barbara, no date, F.E. Winters (0/1 CAS; 1/2 CU). Santa Cruz Co.: Zayante Creek, 72-06-03, J.E.
Cronin (1 /0 JEC). Santa Cruz Mts., no date, no collr. (1 /6 CAS). Zayante, 47-08-26, no collr. (0/1 CAS). Santa Cruz
Mts., no date, A. Koebele (2/3 USNM). Sierra Co.: N. Fork Yuba R. above Indian Valley, 61-08-26, H.B. Leech (1/0
CAS). Siskiyou Co.: Shasta Retreat, 2416’, no date, no collr. (2/0 CAS). Etna Creek 1.5 mi. SW of Etna, 3100’,
70-08-20, H.B. Leech (1/2. CAS). No site, no date, no collr. (0/1 CAS). Sonoma Co.: Guerneville, 08-07-23, F.E.
Blaisdell (1/2 CAS). Mark West Creek at Calistoga Rd., ca. 4 mi. S. Petrified Forest, 63-07-08, H.B. Leech (1/0
CAS). Duncan Mills, 05-07-25, F.E. Blaisdell (1/0 CAS). Camp Meeker, no date, Wintersteiner (1/1 CAS). Duncan
Mills, 08-07-14, F.E. Blaisdell (2/0 CU). Duncan Mills, 08-07-14 (1/0 UMI). Duncan Mills, 08-07-14, no collr. (3/1
CFMNH). Duncan Mills, 08-07-24, no collr. (1/0 USNM). Tehama Co.: 1 mi. SW Government Camp, clear mt.
stream, 6000’, 60-07-29, H.B. Leech (2/1 CAS). Dead Mule Spring, 3 km by road N. of Paskenta-Covelo Rd., 1570 m,
72-08-29, H.B. Leech (1/0 CAS). Trinity Co.: Mad River, 6 mi. S. Ruth, 60-07-31, H.B. Leech (8/6 CAS). Wilson
Cr., Lake Mtn. area, 60-07-30, H.B. Leech (5/3 CAS). S. Fork Van Horn Cr., 2 mi. from mouth at Upper Mad R.,
moss-edged rock pools in running stream, open area, 3000’, 70-08-09, H.B. Leech (6/6 CAS). Mad River at route 36,
nr. Mad River Park, 68-07-20, H.B. Leech (2/1 CAS). Little Brown Cr. at route 3, ca. 3 mi. airline SW Douglas City,
70-08-1 1, H.B. Leech (6/1 CAS). Bridge Gulch Creek at Natural Bridge, 7.5 mi. airline N. Wildwood, 70-08-10, H.B.
Leech (1/4 CAS). Calistoga, 34-06-12, Bryant (7/12 CAS). Van Horn Cr., 1.5 mi. above its mouth at upper Mad
River, clear water pools in gravel and stones of otherwise dry and shaded creek bed, 2850’, 70-08-09, H.B. Leech
(12/15 CAS). Kerlin Cr. at Hyampom-Big Slide Rd„ 68-07-23, H.B. Leech (3/1 CAS). Scott Mtn. Summit
campground, Callahan-Carrville Rd., pool, small stream in drying Darlingtonia bog by camp, 5403’, 70-08-22, H.B.
Leech (0/1 CAS). Hayfork Cr. at Hayfork-Wildwood Rd., 70-08-11, H.B. Leech (0/2 CAS). Mad River just above
mouth Van Horn Cr., 4.25 air miles SE Ruth, pools in drying bed of upper Mad River, 70-08-08, H.B. Leech (0/1
CAS). Mad River at Route 36, nr. Mad River Park, 68-07-20, H.B. Leech (1/0 CAS). Tulare Co.: Sequoia N. Park,
no date, F.E. Winters (1/0 CU). Unspecified Co.: No site, no date, no collr. (1/0 USNM). Oregon: Grant Co.: Spring
at SE corner Grant Co., 67-10-14, J. Schuh (1/0 JS). Multonomah Co.: Portland, no date, Hubbard & Schwarz (3/0
USNM).

3. Hydraena occidentalis new species

Map: Figure 23B
Paratypes: 221

Quaest. Ent., 1980, 16 (1,2)

486

Perkins

Canada: British Columbia: Creston, 30-04-25, G. Stace Smith (1/1 CFMNH). Salmon Arm, Salmon River,
33-10-14, H. B. Leech (1/2 CAS). Salmon Arm, Pumphouse pool. Miles’ Creek, 41-03-25, H. B. Leech (1/0 CAS).
Salmon Arm, Salmon River, 33-10-06, H.B. Leech (0/1 CAS). Frazier Valley, no date, no collr. (3/0 USNM).
Terrace, no date, M.E. Hippisley (3/2 CU). Squamish, 62-07-01, J.L. Carr, (1/1 JLC). Creston, 30-04-25, G. Stace
Smith (1/2 UBC). Creston, ephemeral pond, 2000’, 53-04-06, G. Stace Smith (1/0 UBC). Royal Oak, V. L, 53-08-13,
E. Argyle (1/0 UBC). Silverhope Cr., 9 mi. S. Hope, 71-07-23, P.D. Perkins (3/3 PDP). Cranbrook, 56-08-12, no collr.
(0/3 UBC).

United States: California: Contra Costa Co.: Moraga, 37-04-18, H.B. Leech (1/0 CAS). El Dorado Co.:
Strawberry, 57-09-02, P.S. Bartholomew (2/3 CAS). Humboldt Co.: Conley Cr., 0.8 mi. SE Blocksburg, 1350’,
68-07-09, H.B. Leech (1/2 CAS). Willow Cr., 16-06-14, F.E. Blaisdell (1/3 CAS). Martin Cr., 10 mi. S. Bridgeville,
1150’, 68-07-19, H.B. Leech (0/1 CAS). Orick, 38-05-17, H.B. Leech (1/0 CAS). South Dobbyn Cr.,
Alderpoint-Blocksburg Rd., margin of Typha pool, 450’, 68-07-19, H.B. Leech (1/7 CAS). Lake Co.: Middle Cr., 5 mi.
N. Upper Lake, 55-08-04, H.B. Leech (1/2 CAS). Scott Cr., 2.75 mi. S. of Lower Blue Lake, 55-08-05, H.B. Leech
(1/2 CAS). Hidden Lake, 4 mi. NW of Lakeport, 55-08-05, H.B. Leech (0/1 CAS). Lucerne, pond, 49-05-28, H.B.
Leech (0/1 CAS). Little Blue Lake, 1500', 47-11-08, H.P. Chandler (1/0 CAS). Los Angeles Co.: No site, no date.
Coquillet (1/0 CAS). Mts. nr. Claremont, no date, no collr. (4/0 CMP). Madera Co.: Northfork, 20-03-07, H. Dietrich
(1/1 CU). Marin Co.: Carson Ridge, Woodacre 56-01-09, H.B. Leech (1/0 CAS). No site, 19-11-08, H. Dietrich (1/0
CU). Mariposa Co.: Tenaya L., 45-09-11, G.P. Mackenzie (1/1 LACM). Mendocino Co.: 7 mi. E. of Route 101 on
Longvale-Covelo Rd., Bloody Rum Creek, 1100’, 68-07-18, H.B. Leech (5/3 CAS). 1 mi. S. Covelo, Grist Creek,
68-07-17, H.B. Leech (0/1 CAS). 1 mi. N. Covelo, W. Branch Mill Cr., 68-07-17, H.B. Leech (1/0 CAS). 2 mi. NW
Philo, Hendy Woods S.P., Navarro River, 64-07-22, P. Rubtzoff (1/0 CAS). Mendocino, 57-07-21, J.R. Heifer (0/1
CAS). Mendocino, ex moss in bed of dried-up woodland pool, Berlese funnel, 54-08-07, J.R. Heifer (0/1 CAS). Parson
Cr., 4.5 mi. NE of hopland, 64-06-30, H.B. Leech (1/0 CAS). 15 mi. W. Willits, stream, 48-06-15, H.B. Leech (2/1
CAS). Monterey Co.: Salinas, no date, no collr. (1/0 CU). Little Sur R. at Hwy. 1, 71-10-24, P.D. Perkins (1/0 PDP).
Napa Co.: No site, no date, no collr. (1/0 USNM). Calistoga, 34-06-12, Bryant (6/3 CAS). No site, no date, no collr.
(0/2 CAS). Placer Co.: Penryn, no date, no collr. (1/1 CAS). Riverside Co.: San Jacinto Mts., no date, F.E. Winters
(3/13 CU). Riverside, no date, F.E. Winters (2/2 CU). Santa Barbara Co.: Santa Barbara, no date, F.E. Winters (3/7
CU). Santa Clara Co.: Stanford Univ., 57-03-24, P.S. Bartholomew (1/0 CAS). Siskiyou Co.: Salmon Trinity Alps
Wilderness Area, Big Hat Camp, Josephine Creek at Carter’s Trinity Alps Lodge, 5150’, 68-08-02, H.B. Leech (1/0
CAS). Sonoma Co.: Sonoma Creek, Glen Ellen, 50-04-29, H.B. Leech (3/5 CAS). Duncan Mills, 09-07-26, F.E.
Blaisdell (1/0 CAS). Tehama Co.: 12 mi. SW Red Bluff, Montgomery FFS, 72-06-25, D.S. Chandler (1/0 US). As
above, 72-07-14 (0/1 UA). Oregon:Clackamas Co.: 4 mi. S. Newberg, BL trap, 69-08-11, no collr. (1/0 ODA). Coos
Co.: Coos Bay, 51-07-09, B. Malkin (0/2 CFMNH). Curry Co.: Pistol River, 56-09-17, B. Malkin (1/2 CFMNH). As
above, 52-06-18 (0/1 CFMNH). B. Malkin & V.E. Roth (0/1 CFMNH). Klamath Co.: Aspen Lake, 57-05-05, J.
Schuh (1/1 JS; 1/4 NMD; 2/1 WRS). Lane Co.: Eugene, BL trap, 68-07-29, no collr. (0/1 ODA). Lincoln Co.: 5 mi.
S. Newport, BL trap, 61-08-01, no collr. (0/1 ODA). Polk Co.: West Salem, 71-06-20, R.L. Westcott (0/1 ODA).
Washington: King Co.: Green River Gorge, 56-07-15, B. Malkin & R. Kottke (19/24 CFMNH). Thurston Co.:
Olympia, no date, no collr. (2/2 MCZ). Whatcom Co.: Lynden, 68-04-21, L. Russell (1/1 NMD). Whitman Co.:
Pullman, no date, C.V. Piper (1/0 USNM).

4. Hydraena tuolumne new species

Map: Figure 23E
Paratypes: 46

United States: California: Calaveras Co.: Big Trees, 37-09-13, F.E. Blaisdell (1/0 CAS). Fresno Co.: S. Fk.
Tamarack Cr. at Tamarack Meadow, ca 6 mi. airline south of Huntington L., pools in drying streambed, 7440’,
71-09-02, H.B. Leech (1/0 CAS). Florence Lake, 50-08-24, P.S. Bartholomew (1/0 CAS). Stream from E. entering S.
Fk. San Joaquin R. at gauging station by N. end Jackass Dike, N. of Florence Lake, 7200’, 71-08-31, H.B. Leech (1/0
CAS). Wishon vicinity, 70-08-02, D.G. Marqua (1/0 PDP). Madera Co.: E. fork Granite Creek at road to Soldier
Meadow, 71-08-23, H.B. Leech (14/20 CAS). Chiquito Creek at bridge, Clover Mdw. road, 6800’, 71-08-11, H.B.
Leech (1/0 CAS). N. Fork San Joaquin River at Sheep Crossing, 6000’, 71-08-22, H.B. Leech (1/0 CAS). Nevada
Co.: Shotgun L., 23-07-13, J.O. Martin (1/1 CAS). Upper Truckee River, 52-08-19, P.S. Bartholomew (1/0 CAS).
Tuolumne Co.: Same data as Holotype (2/0 Cas).

5. Hydraena angulicollis Notman

Map: Figure 25A
Specimens examined: 184

Canada: Alberta: Tp. 38 Rge. 5 W. 5 Mer., 72-09-16, B. & J. Carr (2/1 JLC). Tp. 28 Rge. 5 W. 5 Mer., 72-10-06,

Western Hemisphere Hydraenidae

487

B. & J. Carr (1/0 JLC). Jumpingpound Cr., 72-05-13, Carr (0/1 JLC). Tp. 37 Rge. 5 W. 5 Mer., 72-09-10, B. & J.
Carr (0/3 JLC). Tp. 38 Rge. 6 W. 5, 72-09-16, B. & J. Carr (0/1 JLC). Tp. 37 Rge. 5 W. 5 Mer., 72-05-27, B. & J.
Carr (0/1 JLC). Tp. 25 Rge. 5 W. 5 Mer., 72-05-23, B. & J. Carr (0/1 JLC). Edmonton, 18-04-18, F.S. Carr (1/0
UM). Edmonton, 17-09-15, F.S. Carr (0/1 CAS). Edmonton, 19-04-19, F.S. Carr (0/1 CNC). Edmonton, 19-06-19,
F.S. Carr (0/1 CNC). Edmonton, 19-06-19, F.S. Carr (3/3 CAS). Edmonton, 18-04-04, F.S. Carr (0/1 CAS).
Edmonton, 19-08-28, F.S. Carr (0/1 CAS). Edmonton, 19-04-19, F.S. Carr (1/1 CAS). Manitoba: Ninette, in shore
debris, 58-05-06, R.B. Madge (0/1 CNC). Northwest Territories: 3.5 mi. SE Ft. Simpson, 72-06-21, A. Smetana (1/0
CNC). As above, 72-06-17, A. Smetana (0/1 CNC). Norman Wells, 49-06-10, S.D. Hicks (0/2 CNC). Ontario:
Algonquin Park, lake of two rivers nature trail, 60-05-25, B.V. Peterson (0/1 CNC). Dryden, small lake edge, 70-09-04,

E. J. Kiteley (1/0 EJK). Quebec: Wakefield, 31-08-07, W.J. Brown (7/7 CNC). As above, 30/06-04, W.J. Brown (0/3
CNC). Duchesnay, 42-07-08, J.l. Beaulne (0/1 CNC). Kazubazua, 31-08-18, W.J. Brown (3/3 CNC). As above,
28-08-26, W.J. Brown (2/3 CNC). Tremblant, Parc du Mont, 58-05-28, A. Robert (1/0 UM). As above, 58-06-09 (1/0
UM). As above, 58-06-13 (0/1 UM). As above, 58-05-26 (0/1 UM). Duparquet, 35-08-02, G. Stace Smith (1/0 CAS).
As above 37-8-18 (0/1 CAS). Knowlton, 30-06-05, L.J. Milne (0/1 CNC).

United States: Connecticut: Fairfield Co.: No site, no date, no collr. (0/1 USNM). Litchfield Co.: Cornwall,
22-04-30, K.F. Chamberlain (2/0 JFB). Indiana: Kosciusko Co.: No site, 08-06-24, W.S. Blatchley (0/2 PU). Maine:
Penobscot Co.: Corinth, 69-07-22, S. Malcolm (0/1 DCM). Maryland: Anne Arundell Co.: Odenton, 18-07-14, H.
Dietrich (1/0 USNM). Massachusetts: Middlesex Co.: Tyngsboro, no date, no collr. (1/0 USNM). Tyngsboro,
1873-12-01, no collr. (5/4 MCZ). Tyngsboro, no date, no collr. (1/0 USNM). Norfolk Co.: Natick, 49-04-13, C.A.
Frost (1/0 CAS). Unspecified Co.: No site, no date, no collr. (1/0 MCZ). Michigan: Emmet Co.: 4 mi. E. Levering,
52-08-05, P.J. Spangler (1/0 USNM). Maple River, 52-08-08, P.J. Spangler (1/0 USNM). Livingston Co.: E.S.
George Reserve, Big Swamp, 52-07-04, F.N. Young (1/1 UM1). E.S. George Reserve, 50-04-17, l.J. Cantrall (1/0
FNY). Mackinac Co.: 4 mi. E. Engadine, 72-08-21, W.R. Suter (5/3 USNM). Marquette Co.: Marquette, no date,
Hubbard and Schwarz (0/1 USNM). Minnesota: Clearwater Co.: Itasca State Park, 27-11-01, S. Garthside (1/0
USNM). Mille Lacs Co.: 2 mi. E. and 2 mi. S. Onamia, from leaf litter using a Berlese funnel, 65-07-05, P.J. Clausen
(4/3 UMA). Onamia, 65-06-19, P.J. Clausen (1/0 UMA). New Hampshire: Grafton Co.: Franconia, no date, no collr.
(0/1 AMNH). Hillsboro Co.: Antrim, 42-10-16, C.A. Frost (1/1 CAS). New Jersey: Morris Co.: Towaco, sifting
leaves, 44-11-07, A. Nicolay (0/1 USNM). New York: Hamilton Co.: Hope (N.): Hope Falls Road, sphagnum,
streamside alder swamp, 74-08-25, W.R. Suter (41/22 USNM). Oneida Co.: Cold Brook, 16-06-30, W.A. Clemens
(0/1 USNM). Orange Co.: West Point, 10-05-21, W. Robinson (1/0 USNM). Ohio: Unspecified Co.: No site, no date,

F. C. Bowditch (1/1 MCZ). Vermont: Bennington Co.: No site, no date, no collr. (1/0 USNM: 1/0 CU). Windsor Co.:
Woodstock, no date, Wintersteiner (1/1 CU).

7. Hydraena nigra Hatch

Map: Figure 27F

Specimens examined: 1 16

Canada: British Columbia: Fernie, 34-06-05, H.B. Leech (0/1 CAS). Trinity Valley, trib. to Vance Creek,
46-10-03, H.B. Leech (7/3 CAS; 1/1 CNC; 0/1 UBC). Fernie, Lizard Creek, 34-08-27, H.B. Leech (0/1 CAS).
Fernie, 34-06-05, H.B. Leech (0/2 CAS).

United States: California: El Dorado Co.: Gin. Alpine, no date, A. Fenyes (1/1 CFMNH). 2 mi. SSE Quintette,
trib. Whaler Cr., 63-07-27, H.B. Leech (3/1 CAS). Fresno Co.: Stream from E. entering S. Fork San Joaquin R. at
gauging station by N. end Jackass Dike, N. of Florence Lake, 7200’ , 71-08-31, H.B. Leech (1/0 CAS). Kern Co.:
Shirley Cr. at Glenville-Kernville Rd., Greenhorn Mts., 5500’, 70-03-25, H.B. Leech (0/1 CAS). Lassen Co.: Norval
Flats, 5500’, 20-07-04, no collr. (5/3 CAS). Madera Co.: Boggy Mdws., 6000’, 45-07-15, no collr. (0/1 CAS).
Mariposa Co.: NE slope Chowchilla Mts., bog by Stove Pipe campground, 6100’, 71-08-06, H.B. Leech (0/1 CAS).
Nevada Co.: Sagehen Cr., 66-06-22, W.J. Turner (1/1 UCB). Placer Co.: Lake Tahoe, no date, Hubbard and Schwarz
(0/1 USNM). Lake Tahoe, no date, no collr. (1/0 LACM). Riverside Co.: San Jacinto Mts., no date, F.E. Winters
(1/0 CAS; 1/0 CU). Siskiyou Co.: Wolf Cr., Scott Mts. S. of Callahan, 5200’, 70-08-24, H.B. Leech (0/1 CAS). Fox
Lake Road, headwaters Blue Jay Creek, 5000’, 70-08-24, H.B. Leech (2/4 CAS). Tulare Co.: Sequoia N. Park, no
date, F.E. Winters (5/16 CU). Tuolumne Co.: Trib. Niagara Cr., Niagara Cr. Forest Campground, 63-08-11, H.B.
Leech (5/8 CAS). Pinecrest, 47-07-15, P.H. Arnaud, Jr. (1/1 CAS). Colorado: Chaffee Co.: Buena Vista, no date, no
collr. (1/0 USNM). Buena Vista, 7900’-8000’, 1896-07-01, H.F. Wickham (0/8 USNM). El Paso Co.: 6 mi. W.
Colorado Sprs., Gold Camp Road, 9500’, 73-06-06, A.R. Gillogly (4/4 PDP). Oregon: Klamath Co.: 8 mi. NE Bly,
Deming Creek, 67-08-19, J. Schuh (3/0 JS). 12 mi. NE Bly, Long Creek, 67-09-24, J. Schuh (2/3 JS). 15 mi. NE Bly,
Deming Creek, 66-08-05, J. Schuh (1/1 JS). Utah: Cache Co.: Logan Canyon, in moss, 74-10-20, G.F. Knowlton (1/0
USNM). Garfield Co.: Canyon City, no date, Hubbard & Schwarz (2/0 USNM). Uintah Co.: Cub River Cyn.,
56-12-04, G.F. Knowlton (0/1 OSU).

Quaest. Ent., 1980, 16 (1,2)

488

Perkins

8. Hydraena atlantica new species

Map: Figure 25B
Paratypes: 199

Canada: Quebec: Tremblant, Parc du Mont, 52-06-12, A. Robert (0/1 UM). As above, 58-05-28 (1/2 UM). As
above, 58-05-24 (0/1 UM). As above, 58-05-30 (0/1 UM). Kazubazua, 31-08-18, W.J. Brown (1/0 CNC).

United States: Connecticut: Fairfield Co.: No site, no date, no collr. (5/6 USNM; 2/2 MCZ). Litchfield Co.:
Litchfield, 22-04-28, L.B. Woodruff (1/0 AMNH). Illinois: Unspecified Co.: No site, no date, no collr. (0/1 CU).
Maine: Cumberland Co.: North Yarmouth, 67-08-16, P.J. Spangler (2/0 USNM). Maryland: Anne Arundel Co.:
Odenton, 18-07-14, H. Dietrich (0/2 USNM). Montgomery Co.: Plummer’s Island, in pothole, 72-04-01, P.J. Spangler
(1/0 USNM). As above, 72-04-19, P.J. Spangler (3/6 USNM). Plummer’s Island, 72-04-19, P.J. Spangler (1/0
USNM). C. & O. Lock at Plummer’s Island, 60-06-29, P.J. Spangler (2/0 USNM). As above, 61-06-07 (4/1 USNM).
Prince Georges Co.: Bladensberg, no date, no collr. (1/2 CU). Talbot Co.: Easton , woodland pond, 71-07-19, P.J.
Spangler (1/0 USNM). Easton, Seth State Forest, 74-06-19, P.J. Spangler (1/0 USNM). As above, 76-05-13 (15/25
USNM). Massachusetts: Bristol Co.: Fall River, 08-08-28, N.S. Easton (1/0 MCZ). Fall River, no date, N.S. Eston
(0/4 CAS). Hampden Co.: West Springfield, 03-08-03, F. Knab (1/0 USNM). Middlesex Co.: Sherborn, no date, no
collr. (1/0 CU). Framingham, pasture pool, 35-05-10, C.A. Frost (1/0 CAS). Norfolk Co.: Brookline, no date, F.C.
Bowditch (1/0 MCZ). Plymouth Co.: Marion, no date, no collr. (2/0 MCZ). Suffolk Co.: Boston, no date, no collr.
(1/0 MCZ). Tyngsboro, no date, no collr. (1/4 CU). Unspecified Co.: No site, no date, no collr. (1/0 CMP; 2/0
SDSU). Lawrence, no date, no collr. (1/0 CFMNH). Michigan: Eaton Co.: Grand Ledge, no date, Hubbard &
Schwarz (0/3 USNM). New Hampshire: Merrimack Co.: Danbury, no date, no collr. (1/0 USNM). Stafford Co.: Lee,
61-07-25, R.L. Blickle (1/0 UNH). Unspecified Co.: No site, no date, no collr. (1/0 USNM). Three Mile Island,
27-05-08, no collr. (1/0 MCZ). New Jersey: Bergen Co.: Seacaucas, no date, Wintersteiner (1/3 CU). Hackensac, no
date, Wintersteiner (2/2 CU). Westwood, No date, no collr. (1/0 CU). Westwood, 19-07-01, no collr. (3/2 AMNH).
Oradell, 18-04-07, E D. Quirsfeld (1/0 USNM). Oradell, 18-04-06, E.D. Quirsfeld (1/0 JFB). Mercer Co.: Trenton,
10-03-29, H.B. Kirk (1/0 PBP1). Passaic Co.: Paterson, 10-04-01, no collr. (0/2 AMNH). Unspecified Co.: Snake Hill,
no date, no collr. (1/4 AMNH). No site, no date, no collr. (1/1 CAS; 1 /I USNM). As above, Wintersteiner (4/0 CU).
New York: Richmond Co.: Staten Island, 16-0930, no collar. (0/1 USNM). Staten Island, no date, no collr. (1/0
CAS). Staten Island, 91-07-07, no collr. (0/1 USNM). Suffolk Co. Long Island, no date, no collr. (1/2 MCZ). As
above, Wintersteiner (10/2 CU). Long Island, Forest Park, no date, no collr. (8/6 CU). Long Island, Shelter Island,
40-05-29, R. Latham (1/0 CU). Tompkins Co.: Ithaca, 15-04-14, no collr. (01 CU). Ithaca, 55-04-30, H. Dietrich (0/2
CU). Westchester Co.: New Rochelle, 10-08-03, L. Lacey (0/2 AMNH). Unspecified Co.: No site, no date, no collr.
(1/0 UMA; 0/1 USNM). No site, no date, C. Palm (1/2 AMNH). Pennsylvania: Delaware Co.: Castle Rock, no date,
H.A. Wenzel (2/0 OSU). Unspecified Co.: No site, no date, F.C. Bowditch (1/1 MCZ). Rhode Island: Newport Co.:
Tiverton, 12-10-20, Dodge (1/1 PMNH). Washington Co.: Kingston, 21-02-04, no collr. (0/1 CU). South Carolina:
Charleston Co.: No site, 66-10-13, R.E. Widdows (1/1 CFMNH). Vermont: Bennington Co.: No site, no date, no collr.
(15/11 USNM; 1/0 CMP; 0/1 CU). Virginia: Unspecified Co.: Fort Monroe, no date, no collr. (1/1 USNM).
Wisconsin: Sauk Co.: Sauk City, 99-08-02, no collr. (1/1 MCZ). Sauk City, 99-08-09, no collr. (1/4 UW).

9. Hydraena pacifica new species

Map: Figures 27A-C
Paratypes: 634

Canada: Alberta: Pincher Creek, no date, no collr. (2/3 MCZ). Coleman, 58-08-04, J.L. Carr (2/1 JLC). 6 mi. S.
Pincher Creek, 71-07-01, P.D. Perkins (1/0 PDP). British Columbia: Terrace, no date, M.E. Clark (1/2 MCZ).
Quesnel Lake, no date, no collr. (1/3 MCZ). Fernie, Elk River, 34-07-26, H.B. Leech (4/3 CAS). Fernie, 34-06-05,
H.B. Leech (1/1 CAS). Terrace, no date, M.E. Clark (4/0 CAS). Trinity Valley, tributary to Vance Creek, 46-10-03,
H.B. Leech (6/8 CAS). As above, 44-07-12 (2/0 CAS). As above, 37-09-12 (1/3 CAS). As above, 40-06-13 (0/1
CAS). Kamloops, in a swamp, 39-07-30, G. Spencer (0/2 CAS). Terrace, Lost lake, no date, M.E. Hippisley (1/0
CAS). British America, Ft. McLeod, no date, no collr. (2/0 USNM). Terrace, no date, M.E. Hippisley (2/0 CU).
Princeton, 30-05-25, G. Stace Smith (1/0 UBC). Wynndel, head of Lizard Creek, 47-08-28 (2/1 UBC). As above,
46-10-05 (1/2 UBC). As above, 45-10-07 (1/0 UBC). Wynndel, Duck Creek, 31-07-18, G. Stace Smith (0/1 UBC). As
above, 31-07-10 (0/1 UBC). Wynndel, Lizard Creek, 2600’, 47-10-12, G. Stace Smith (1/0 UBC). Copper Mtn.,
30-03-28, G. Stace Smith (5/6 UBC). As above, 30-05-04 (1/1 UBC). As above, 30-09-04 (1/0 UBC). As above,
30-03-29, (2/1 CNC). As above, 29-05-17 (0/2 CNC). Creston, ephemeral pond, 2000’, 52-03-21, G. Stace Smith (1/1
UBC). Royal Oak V. I., evening flight, 53-07-17, E. Argyle (1/2 UBC). Terrace, no date, M.E. Clark (1/4 MCZ).
Quesnel Lake, no date no collr. (1 /3 MCZ). Lister, Rykert Creek, 47-07-02, G. Stace Smith (2/4 UBC).

United States: California: Fresno Co.: Ca 6 mi. S. Huntington Lake, S. Fork Tamarack Cr. at Tamarack Meadow,
pools in drying streambed, 7440’, 71-09-02, H.B. Leech (3/9 CAS). N. of Huntington Lake, 71-08-25, H.B. Leech

Western Hemisphere Hydraenidae

489

(11/17 CAS). NE of Huntington Lake, Kaiser Pass Meadow, 9025’, 71-08-27, H.B. Leech (46/60 CAS). N. of
Florence Lake, stream from E. entering S. Fork San Joaquin R., at gauging station by N. end Jackass Dike, 7200’,

71- 08-31, H.B. Leech (0/1 CAS). Glenn Co.: Plaskett Mdws., margins of Upper Plaskett Lake, 6000’, 60-07-29, H.B.
Leech (10/13 CAS). 4.5 mi. S. Mendocino Pass, collecting stop No. 5, 6500’, 60-07-29, H.B. Leech (0/4 CAS). Inyo
Co.: Cottonwood Cr., ex waterlogged limb in stream, 10,000’, 71-05-16, P.D. Perkins (2/6 PDP). Lassen Co.: Duck
Lake, 21-05-08, J.O. Martin (1/1 CAS). Facht, 21-05-24, no collr. (1/3 CAS). Los Angeles Co.: Pomona, no date, no
collr. (1/0 MCZ). Madera Co.: Jackass Creek, E. end Jackass Meadow, 6960’, 71-08-17, H.B. Leech (9/8 CAS).
Chiquito Creek, at bridge Clover Meadow Road, 6800’, 71-08-11, H.B. Leech (1/2 CAS). E. Fork Granite Creek at
road to Soldier Meadow, 6960’, 71-08-23, H.B. Leech (1/0 CAS). Branch, Granite Cr., 0.15 mi. W. Soldier Meadow,
6965’, 71-08-17, H.B. Leech (0/1 CAS). Chiquito Creek, 0.25 mi. below upper Chiquito campground, 6820’, 71-08-1 1,
H.B. Leech (0/1 CAS). Mariposa Co.: Yosemite N. Park, Snow Flat, 46-09-07, H.P. Chandler (1/0 CAS). Mirrow
Lake, 55-08-21, P.S. Bartholomew (0/6 CAS). Tenaya L„ 45-09-11, G.P. Mackenzie (2/1 LACM; 2/0 NMD).
Nevada Co.: Sagehen Creek, nr. Hobart Mills, 66-06-26, W.J. Turner (2/0 UCB). Sagehen Cr., 66-06-23, W.J. Turner
(1/0 UCB). Upper Truckee R., 52-08-19, P.S. Bartholomew (1/0 CAS). Siskiyou Co.: 6.25 mi. airline SW Etna,
stream flowing into Meeks Meadow, 1925 m, 72-08-23, H.B. Leech (9/13 CAS). S. of Callahan, East Boulder Lake,
Scott Mts., 6680’, 70-08-25, H.B. Leech (4/1 CAS). Poker Flat, head of W. Branch Indian Creek, 5040’, 66-08-14,
H.B. Leech (6/2 CAS). 6.25 mi. airline SW Etna, murky flood pool by stream flowing into Meeks Meadow Lake,

72- 08-23, H.B. Leech (34/51 CAS). Fox Lake Road, headwaters Blue Jay Creek, 5000’, 70-08-24, H.B. Leech (3/0
CAS). Taylor Lake, Salmon Mts., small stream, meadow south end Taylor Lake, 6500’, 70-08-20, H.B. Leech (9/10
CAS). Tiny creek, NW side Scott Mt„ 6660’, 66-08-20, H.B. Leech (1/1 CAS). Headwaters E. Fork of S. Fork
Salmon River, Cecilville-Callahan Road, 6000’, 68-07-31, H.B. Leech (2/6 CAS). Stream in Darlingtonia Bog, source
Big Carmen Creek, NNW slope Scott Mtns., 70-08-23, H.B. Leech (2/2 CAS). Upper Boulder Lake, 6780’, Scott
Mtns., S. of Callahan, 70-08-25, H.B. Leech (0/1 CAS). Etna Road, N. Russian Creek at foot Jumpoff Joe Curve,
3640’, 70-08-17, H.B. Leech (0/1 CAS). Meeks Meadow lake, 6.25 mi. airline SW Etna, 1872 m, 72-08-23, H.B.
Leech (0/1 CAS). Tehama Co.: Judd Cr., 52-06-25, H.P. Chandler (0/1 CAS). Trinity Co.: Scott Mtn. summit
campground, Callahan-Carrville Rd., pools, small stream in Darlingtonia bog by camp, 5403’, 70-08-22, H.B. Leech
(1/0 CAS). Tuolumne Co.: Tioga, 45-09-11, G.P. Mackenzie (2/1 LACM). Sonora Pass, 58-08-16, D. Giuliani (2/0
CAS). Unspecified Co.: No site, no date, no collr. (1/0 INHS). Colorado: Chaffee Co.: Buena Vista, no date, F.E.
Wickham (2/3 USNM). Conejs Co.: Cumbres Creek, E. slope of Cumbres Pass, 9920’, 65-08-12, H.B. Leech (2/0
CAS). Costilla Co.: Fort Garland, no date, Hubbard & Schwarz (0/1 USNM). Huerfano Co.: Veta Pass, no date, no
collr. (1/1 MCZ). Veta Pass, no date, Hubbard & Schwarz (4/2 USNM). La Veta, no date, Hubbard & Schwarz (0/1
USNM). Veta Pass, no date, no collr. (3/1 MCZ). Routt Co.: Steamboat Springs, 6800’, 41-10-01, Bryant (1/0 CAS).
Clark, 8000’, 47-08-03, Bryant (1/0 CAS). Summit Co.: Fremont Pass, 10,300’, 52-08-17, B. Malkin (0/1 CFMNH).
Idaho: Bingham Co.: No site, no date, Hubbard & Schwarz (1/1 USNM). Blaine Co.: Alturas Lake, Sawtooth Mts.,
52-07-23, B. Malkin (1/1 CFMNH). As above, 52-07-22 (1/1 CFMNH). Custer Co.: Stanely lake, Sawtooth Mts.,
52-07-23, B. Malkin (2/1 CFMNH). Montana: Cascade Co.: 7.5 mi. N. Neihart, Belt Creek, 6950’, 64-07-21, H.B.
Leech (6/8 CAS). Nevada: Elko Co.: E. foot Secret Pass, Hwy. 1 1 at road from Arthur, 6200’, 65-08-26, H.B. Leech
(1/3 CAS). Lander Co.: 5 mi. ESE Austin Hwy. 50 at Hwy. 21, 64-08-05, H.B. Leech (0/1 CAS). Washoe Co.: 0.5
mi. E. Top Pass, stream under route 27, E. slope Mt. Rose, 8800’, 69-08-27, H.B. Leech (1/0 CAS). Oregon:
Clackamas Co.: Clackamas Lake, 40-07-20, no collr. (1/1 MCZ). Harney Co.: Fish Lake, Steens Mts., 51-06-22, B.
Malkin (11/9 CFMNH). Klamath Co.: Crescent, Little Deschutes River, 57-05-12, J. Schuh (1/0 JS). Bly, Horse
Glades, 55-05-05, J. Schuh (1/0 JS). Lake Co.: Lake City, sweeping plants, springs and seepage, 67-08-02, K. Goeden
(2/4 ODA). Lane Co.: 2 mi. N. Junction City, 72-02-12, Ryker (0/1 ORSU). Utah: Cache Co.: Logan Canyon, in
moss, 74-10-20, G.F. Knowlton (3/0 USNM). Emery Co.: Wasatch MTts., 47-06-28, Bryant (0/1 CAS). Garfield Co.:
Escalante River, mouth of calf creek, 39-08-01, H.P. Chandler (0/2 CAS). City Can., no date, Hubbard & Schwarz
(0/1 USNM). Salt Lake Co.: Alta, no date, Hubbard & Schwarz (1/0 USNM). Utah Co.: Timpanogas, Aspen Grove
environs, 7000’, 41-22-05, H.P. Chandler (1/2 CAS). Hobble Cr. Canyon, 6000’, 41-08-09, H.P. Chandler (0/2 CAS).
Wasatch Co.: Lost Lake Camp, Uinta Mts., 9800’, 40-08-26, H.P. Chandler (0/1 CAS). As above, 40-08-27 (0/1
CAS). As above, 8000’, 40-08-26 (1/0 CAS). Tyrol Lake, Uintah Mts., 9800’, H.P. Chandler (1/2 CAS). Washington:
King Co.: Bothell, 61-03-21, no collr. (0/1 DCM). Green River Gorge, 56-07-15, B. Malkin & R. Kottke (1/0
CFMNH). Wyoming: Uintah Co.: 8.3 mi. W. Fr. Bridger, trib. of muddy Cr., 65-08-23, F.O. Leech (0/1 CAS).
Yellowstone National Park: Yellowstone, N. P., Apollinasis Spr., 62-08-17, P. & P.J. Spangler (1/0 USNM).
Yellowstone N.P., colld. in Obsidian Creek at Crystal Spring, 62-08-17, P. & P.J. Spangler (6/19 USNM).

Aedeagal morph “B”

Specimens examined: 177

Canada: British Columbia: Jaffray, Little Sand Creek, 50-07-23, H.B. Leech (3/1 CAS). Sumas Prairie, 33-06-03,
G. Hopping (1 /0 CAS). Agassiz, 31-03-07, H.B. Leech (1 /2 CAS). Victoria, Vancouver, no date, Horn (1 /0 USNM).

United States: California: Contra Costa Co.: Hills back of Oakland, 08-06-07, no collr. (0/1 CAS). Danville,
51-06-01, F.X. Williams (1/1 CAS). Berkeley, no date, F.E. Winters (0/1 CAS). Del Norte Co.: 2 mi. S. Crescent
City, roadside pond, 67-03-29, J. Schuh & D. Vertrees (2/1 JS). 8 mi. NE. Cresent City, Smith River at Hiouchi

Quaest. Ent., 1980, 16 (1,2)

490

Perkins

bridge, 65-09-30, H.B. Leech (1/0 CAS). Humboldt Co.: Hydesville, no date, no collr. (0/3 CAS). Mad River at
Kneeland-Addison Rd., 66-08-09, H.B. Leech (1/0 CAS). Lake Co.: Kelseyville, Kelsey Creek, 49-05-29, H.B. Leech
(1/4 CAS). Los Angeles Co.: No site, no date, no collr. (1/5 CU). Marin Co.: Novato, streambed by sifting, 52-06-17,
H.B. Leech (15/10 CAS). Fairfax, no date, F.E. Blaisdell, (2/3 CAS). As above, 06-09-09 (0/1 CAS). Lagunitas
Creek at Tocaloma, 68-05-04, H.B. Leech (1/0 CAS). Olema, 48-03-01, H P. Chandler (1/0 CAS). Headwaters of
Salmon Dr., Wilson Hill Rd., 64-02-22, H.B. Leech (1/0 CAS). Mariposa Co.: Miami Ranger Station, 5000’, 42-07-06,
H.P. Chandler (0/1 CAS). 6 mi., E. Miami Ranger Station, 46-07-04, H.P. Chandler (1/0 CAS). Mendocino Co.:
Parson Creek 4.5 mi. NE. of Hopland, 64-06-30, H.B. Leech (2/3 CAS). Univ. Cal. Range Exp. Sta., Vasser Corner
Creek, 63-06-20, H.B. Leech (1/0 CAS). Grist Creek, 1 mi. S. Covelo, 68-07-17, H.B. Leech (1/0 CAS). Rodeo Creek,
1 mi. S. Tatu, Longvale-Dos Rios Road, 68-07-17, H.B. Leech (2/1 CAS). Mono Co.: Mammoth, 45-09-15, G.P.
Mackenzie (1/0 LACM). Monterey Co.: Salinas, no date, no collr. (0/1 CAS). Napa Co.: Rutherford, 51-06-10, H.B.
Leech (1/0 CAS). San Mateo Co.: Woodside, Pulgas Temple, 51-06-10, P.S. Bartholomew (0/7 CAS). No site, no
date, no collr. (1/0 USNM). Santa Barbara Co.: Santa Barbara, no date, F.E. Winners (1/0 CAS). Santa Clara Co.:
Stanford Univ., 57-03-24, P.S. Bartholomew (2/1 CAS). Stanford Univ., Jasper Ridge, 52-05-31, P.S. Bartholomew
(2/2 CAS). Sierra Co.: Sierraville, 4950’, 47-07-03, H.P. Chandler (3/3 CAS). Sonoma Co.: Duncan Mills, 08-07-26,
F.E. Blaisdell (0/1 CAS). Santa Rosa-Calistoga, 50-06-25, P.S. Bartholomew (1/0 CAS). Calistoga, 34-06-12, Bryant
(1/0 CAS). Glen Ellen, Sonoma Creek, 50-04-29, H.B. Leech (2/0 CAS). Mark West Cr. at Calistoga Rd., ca 4 mi. S.
Petrified Forest, 63-07-08, H.B. Leech (5/6 CAS). Santa Rosa, 65-04-10, J.D. Birchim (1/0 CAS). Tulare Co.:
Sequoia N. Park, no date, F.E. Winters (2/0 CU). Unspecified Co.: Waddell, no date, J.E. Cronin (1/1 JEC). Little
Miller Creek, 74-08-04, J.E. Cronin (1/0 JEC). Fr. Creek, no date, H.W. Wenzel (2/1 OSU). Oregon: Benton Co.:
Corvallis, no date, no collr. (4/21 USNM). Corvallis, 38-05-20, H.B. Leech (1/0 CAS). Corvallis, no date, no collr.
(5/12 CU). Corvallis, 72-04-26, L. Ryker (1/0 ORSU). Corvallis, no date, no collr. (3/0 MCZ). 10 mi. S. Corvallis,
Winkle Lake, 63-05-10, T. Schuh (0/1 JS). Pub. Golf course pond, 72-06-30, L. Ryker (1/0 ORSU). Granger,
32-04-25, no collr. (1/0 JS). Klamath Co.: Above Geary Ranch, Aspen duff at swamp, 71-10-25, J. Schuh (1/0 JS).
Lane Co.: Eugene, 41-06-29, B. Malkin (3/0 CAS). Washington: King Co.: Bothel, 61-03-21, no collr. (1/0 DCM).
Bothel, 60-04-16, D. Miller (0/1 DCM).

Aedeagal morph “C”

Specimens examined: 73

Canada: British Columbia: Langley, 31-06-21, K. Graham (1/0 CAS). As above, 35-06-23 (2/2 CAS).

United States: California: El Dorado Co.: Strawberry, 57-09-02, P.S. Bartholomew (1/0 CAS). Fresno Co.: Vic.
Wishon, 70-08-02, D.G. Marqua (1/0 PDP). Mariposa Co.: Mirror Lake, 55-08-21, P.S. Bartholomew (1/1 CAS).
Mendocino Co.: Rancheria Cr., 5.5 SE Booneville, 50-06-15, H.B. Leech (1/0 CAS). Napa Co.: Burton Cr., Pope
Valley, 64-05-10, H.B. Leech (2/2 CAS). Nevada Co.: Upper Truckee River, 52-08-19, P.S. Bartholomew (6/10 CAS).
Placer Co.: Emigrant Gap, from pool, 66-07-27, P.H. Arnaud, Jr. (3/7 CAS). Shasta Co.: 2.5 mi. W & S. of Viola,
Bailey Creek, 61-08-31, H.B. Leech (1/0 CAS). Sierra Co.: Sierraville, 4950’, 47-07-03, H.P. Chandler (3/0 CAS).
Siskiyou Co.: No site, no date, F.E. Blaisdell (1/0 CAS). Tulare Co.: Sequoia N. Park, no date, F.E. Winters (2/0
PDP).

1 0. Hydraena californica new species

Map: Figure 23D
Paratypes: 14

United States: California: Humboldt Co.: Redwood Park, 18-08-10, J.O. Martin (1/2 CAS). San Mateo Co.: La
Honda, 25-07-29, F.E. Blaisdell (1/0 CAS). Santa Clara Co.: Alma, 27-08-01, J.O. Martin (3/0 CAS). Los Gatos, no
date, Hubbard and Schwarz (1/0 USNM). Santa Cruz Co.: Santa Cruz, no date, F.W. Nunenmacher (1/0 UMI).
Santa Cruz Mts., no date, Koebele (2/0 CAS). Boulder Creek, 55-01-22, M. Wasbauer (1/0 UCB). Zayante Creek,
72-06-03, J.E. Cronin (0/1 JEC). As above, 73-02-19 (1/0 JEC).

1 1 . Hydraena petila new species

Map: Figure 27E
Paratypes: 96

Canada: British Columbia: Vancouver, 33-04-23, H.B. Leech (4/1 CAS; 1/1 CNC).

United States: California: Del Norte Co.: No site, no date, F.W. Nunenmacher (1/1 CFMNH). Gasquet, 50-06-24,
P.S. Bartholomew (1/2 CAS). Humboldt Co.: Toss-up creek, confluence with Redwood creek 2.5 mi. N. of road to
Hoopa, ca 650’, 70-08-13, H.B. Leech (9/13 CAS). Willow creek just above its E. Fork, 1500', 70-08-28, H.B. Leech
(2/1 CAS). Conley creek, 0.8 mi. SE Blocksburg, 1350', 68-07-19, H.B. Leech (0/3 CAS). Pool in drying up stream
under Route 36, Larabee Valley, 0.8 mi. W. Butte Cr., 2470’, 68-07-19, H.B. Leech (0/2 CAS). Burr Cr. 3 mi. S.

Western Hemisphere Hydraenidae

491

Bridgeville, 1200’, 68-07-19, H.B. Leech (1/0 CAS). Stream under Bair Rd., tributary to Pine Cr. W. of Hoopa,
70-08-14, 3300’, F.O. Leech (2/0 CAS). N. Fork Yager Cr. at Bridgeville-Kneeland Rd., 1300’, 66-08-08, H.B. Leech
(2/0 CAS). Pepperwood, 07-06-28, Bradley (1/0 CU). Stream under Blair Rd., 3 mi. airline WSW of Hoopa, 1950’,
70-08-14, H.B. Leech (0/4 CAS). Mendocino Co.: No site, no date, no collr. (1/1 CAS). Hendy Woods S. P., 68-06-14,
L.N. & C.J. Bell (2/2 CAS). Mendocino, 57-07-21, J.R. Heifer (1/0 CAS). 15 mi. W. Willits, stream, 48-06-15, H.B.
Leech (1/0 CAS). Twin Rocks, 29-07-10, no collr. (1/0 CAS). Gualala Cr., 51-07-11, P.S. Bartholomew (0/1 CAS).
Santa Clara Co.: Stanford Univ., Corte Madera Creek, 51-08-21, P.S. Bartholomew (1/0 CAS). Santa Cruz Co.: 10
mi. S. Holy City, 68-04-27, A. & A. Gillogly (1/0 AG). Zayante Cr., 72-06-03, J.E. Cronin (1/3 JEC). Sonoma Co.:
Duncan Mills, 69-07-21, P. Rubtzoff (3/0 CAS). Camp Meeker, 52-07-10, P.S. Bartholomew (1/2 CAS). Santa Rosa,
50-06-25, P.S. Bartholomew (0/1 CAS). Tehama Co.: Dead Mule Sprint, 3 km by road N. of Paskenta-Covelo Rd.,
1570 m., 72-08-29, H.B. Leech (9/5 CAS). Trinity Co.: S. Fork Van Horn Cr. 2 mi. from mouth at upper Mad River,
3000’, moss-edged rock pools in running stream, open area, 70-08-09, H.B. Leech (1/0 CAS). Van Horn Cr. 1.5 mi.
above its mouth at upper Mad River, , 2850’, clean water pools in gravel and stones of otherwise dry and shaded creek
bed, 70-08-09, H.B. Leech (1/0 CAS). Kerlin Creek at Hyampon-Big Slide Rd., 68-07-23, H.B. Leech (1/0 CAS).

13. Hydraena quadricurvipes new species

Map: Figure 25D
Paratypes: 7

United States: Alabama: Marshall Co.: Grant, nr. River Cave, floor debris, light zone at entrance, 68-05-25, H.R.
Steeves, Jr. (0/1 CFMNH). Georgia: Chattooga Co.: 2 mi. NE Subligna, outside Parker Cave, Berlese; #67 forest
FM(HD) #67-121, 67-06-20, S. Peck & A. Fiske (1/0 CFMNH). Indiana: Brown Co.: Small stream nr. Needmore,
50-02-11, F.N. Young (1/0 PDP). Monroe Co.: Morgan-Monroe State Forest, 61-07-29, J.C. Schaffner (1/0 USNM;
1/1 PDP). Maryland: Montgomery Co.: Glen Echo, 22-06-24, J.R. Malloch (0/1 USNM).

15. Hydraena pennsylvanica Kiesenwetter

Map: Figure 25C
Specimens examined: 610

Canada: Ontario: Pr. Edw. Co., 23-05-01, J.F. Brimley (1/1 JFB). As above, 47-05-12 (1 /0 JFB). No site, no date,
no collr. (0/2 MU). Normandale, 31-06-04, W.J. Brown (1/0 CNC). Marmora, 52-07-22, J.R. Vockeroth (1/2 CNC).
Ottawa, Black Rapids, 27-05-23, W.J. Brown (2/0 CNC). As above, 27-05-11 (0/1 CNC). Trenton, 04-11-23, Evans
(0/1 CNC). Hastings, 05-05,15, Evans (0/1 CNC). Ventnor, 28-08-05, J.A. Adams (3/5 CNC). Ottawa, Black Rapids,
24-05-19, W.J. Brown (1/0 CAS). Quebec: La Trappe, no date, J. Ouellet (1/3 CSQ). Magog, 41-05-24, J.l. Beaulne
(0/1 CSQ). Buffalo, 38-09-07, no collr. (1/1 USNM). Montreal, Berlese-clumps of moss and grass from swampy area
overgrown with willows, 70-06-24, E.J. Kiteley (1/0 EJK). As above, 70-09-10 (0/1 EJK). As above, 70-08-01 (0/1
EJK). As above, 71-11-25 (1/0 EJK). Montreal, moss-Berlese, 70-11-15, E.J. Kiteley (2/4 EJK). Montreal, 70-11-19,
E.J. Kiteley (0/1 EJK). As above, 69-09-07 (0/1 EJK). Montreal, 23-06-20, J. Ouellet (1/0 UM). As above, 05-08-10
(1/5 UM). As above, no date (0/1 UM). As above, 03-06-20 (0/1 UM). La Trappe, 44-07-09, J. Ouellet (1/1 UM).
As above, 37-05-11 (1/2 UM). As above, 37-05-08 (0/1 UM). As above, 33-07-21 (1/0 UM). As above, 44-04-008
(0/1 UM). La Trappe, 43005-23, P. Leopold (1/0 UM). La Trappe, 46-07-29, J. Ouellet (1/0 UM). As above,
45-08-09 (0/1 UM). As above, 35-08-08 (1/0 UM). La Trappe, 37-05-08, P. Leopold (2/3 UM). Rigaud, 37-07-31, A.
Robert (1/2 UM). As above, 39-05-29 (0/1 UM). Berthierville, 50-05-27, A. Robert (0/1 UM). As above, 69-07-30,
(0/1 UM). Cascapedia, 33-08-17, W.J. Brown (3/0 CNC). Aylmer, 29-05-11, W.J. Brown (0/1 CNC). Fairy Lake,
27-10-02, W.J. Brown (1/0 CNC). As above, 27-08-07 (1/0 CNC). As above, 27-05-17 (1/0 CNC). As above,

27- 09-09 (0/1 CNC). Kazubatua, 31-09-18, W.J. Brown (2/3 CNC). As above, 27-06-06 (1/0 CNC). As above,

28- 08-26 (1/2 CNC). Duparquet, Duparquet Lake, 34-11-01, G. Stace Smith (1/0 CAS). Duparquet, 35-08-02, G.
Stace Smith (0/6 CAS). As above, 35-08-26 (0/1 CAS). La Trappe, 37-05-12, J. Ouellet (2/3 CAS). Kazubazua,
28-08-26, W.J. Brown (0/1 CAS). Wakefield, 28-05-05, W.J. Brown (0/1 CAS).

United States: Connecticut: Litchfield Co.: Litchfield, 22-04-28, L.B. Woodruff (1/0 AMNH). Litchfield, stoney
brook, 25-09-29, L.B. Woodruff (1/0 AMNH). Lake Co.: Volo, Sayer Bog (Volo Bog), 66-10-01 (3/3 WRS). As
above, 61-03-16 (1/1 WRS). Tamarack Bog, 46-07-05, H.S. Dybas (1/0 CFMNH). Volo Bog, 68-03-29, A. Smetana
(1/0 CNC). Unspecified Co.: No site, no date, no collr. (2/1 1NHS). Maryland: Unspecified Co.: No site, no date, no
collr. (1/4 UMA). Massachusetts: Bristol Co.: Dighton, no date, no collr. (0/1 MCZ). Swansea, 1 1-05-20, N.S. Easton
(0/1 MCA). Fall River, 02-07-27, N.S. Easton (0/2 UM1). Essex Co.: Lawrence, no date. Crew (0/1 CU). Lawrence,
no date, no collr. (4/1 CMNH). Hampden Co.: W. Springfield, 03-08-04, F. Knab (1/0 USNM). Hampshire Co.:
Northampton, UV light, 71-06-12, E.J. Kiteley (0/1 EJK). Middlesex Co.: Framingham, 34-12-02, N.M. Downie (1/0
NMD). Framingham, 34-11-17, N.M. Downie (0/1 NMD). Framingham, 07-08-18, C.A. Frost (0/2 INHS). Natick,
no date, F.E. Winters (2/0 CU). Wayland, sifting moss, no date, F.E. Winters (1/0 CU). Framingham, no date, C.A.

Quaest. Ent., 1980, 16 (1,2)

492

Perkins

Frost (0/1 CU). Framingham, 36-09-07, C.A. Frost (1/0 UCD). Framingham, 07-09-07, no collr. (1/2 CNC).
Sherborn, 21-10-23, C.A. Frost (1/0 MCZ). Lowell, no date, no collr. (1/1 MCZ). Norfolk Co.: Brookline, 1895-03-24,
F.C. Bowditch (2/1 MCZ). Suffolk Co.: Cambridge, no date, Hubbard and Schwarz (1/1 USNM). Cambridge, no
date, no collr. (0/2 MCZ). Unspecified Co.: No site, no date, no collr. (1/1 MCZ). Michigan: Cheboygan Co.: Nigger
Creek, 52-07-14, P.J. Spangler (3/0 USNM). Livingston Bog, 52-07-14, P.J. Spangler (1/0 USNM). Bryants Bog,
52-07-16, P.J. Spangler (1/0 USNM). Mud Lake Bog, 66-07-24, T. Schuh, E. Evans (0/1 WRS). Clinton Co.: Rose
Lake, 66-03-02, no collr. (4/0 JS). Delta Co.: Escanaba, 58-05-31, E.J. Kiteley (0/1 EJK). Eaton Co.: Grand Ledge, no
date, Hubbard and Schwarz (0/1 USNM). Emmet Co.: Bryant Road, 52-07-25, P.J. Spangler (3/1 USNM). 4 mi. E.
Levering, 52-07-05, P.J. Spangler (1/1 USNM). Maple River, 52-08-08, P.J. Spangler (0/1 USNM). Ingham Co.: Ag.
Coll., no date, no collr. (1/0 USNM). Lansing, no date, no collr. (0/1 MCZ). Lapper Co.: Lapeer St. Game Area,
Cedar Lake Bog, 63-08-25, W. Suter and R.C. Graves (2/3 CFMNH). Livingston Co.: E.S. George Reserve, 50-04-17,
I.J. Cantrall (2/2 CAS). As above, 52-07-22, F.N. Young (35/50 UMI). As above, 51-04-08, I.J. Cantrall (46/60
UM1). As above, 50-04-17, F.N. Young (6/5 FNY). As above, 51-07-09, I.J. Cantrall and F.N. Young (1/0 FNY). As
above, 50-06-10, F.N. Young (0/2 FNY). As above, 51-06-22, F.N. Young (0/1 FNY). As above, 51-07-08, F.N.
Young (0/1 FNY). As above, 51-08-30 (0/1 FNY). As above, 52-06-21 (0/1 FNY). As above, 51-05-18 (1/1 BM).
E.S. George Reserve, Big Cassandra Bog, 58-10-19, M. Englemann (1/0 WRS). Luce Co.: Dollarville, 64-07-31, R.B.
Wilson (1/1 WRS). Midland Co.: No site, 51-07-10, R.R. Dreisbach (1/0 UMI). Shiawassee Co.: T5N, R1E Sec
20-29, 67-06-04, T. Schuh and T. Hlavac (1/0 JS). As above, 67-05-21 (1/0 JS). Washenah Co.: Whitmore Lake,
sweeping grass in swamp, 55-05-14, G.H. Nelson (0/1 WRS). Washtenaw Co.: Ann Arbor, 40-09-25, R. Kenk (1/0
CAS). Wayne Co.: Detroit, no date, Hubbard and Schwarz (3/2 USNM). Detroit, no date, no collr. (2/0 CMP).
Unspecified Co.: No site, no date, no collr. (1/0 USNM). Minnesota: Cass Co.: Leech Lake, 64-08-21, P.H. Arnaud,
Jr. (1/0 CAS). Mille Lacs Co.: 2 mi. E. and 2 mi. S. Onamia, from leaf litter using a Berlese funnel, 65-06-19, P.J.
Clausen (40/8 UMA). New Jersey: Bergen Co.: Westwood, no date, no collr, (6/7 AMNH). Hackensac, no date,
Wintersteiner (3/0 CU). Cape May Co.: Petersburg, no date, no collr. (0/1 MCZ). Morris Co.: Troyhills, 66-08-18,
D.C. Miller (10/8 DCM). Newfoundland, no date, no collr. (0/1 AMNH). Unspecified Co.: No site, no date, no collr.
(1/1 CU). New York: Albany Co.: Rennselaerville: Huyck Preserve, litter in open area of bay, shore of the Myosotis,
74-08-27, W.R. Suter (6/2 USNM). As above. Fir buttress nr. bay (2/1 USNM). As above, lake shore litter under
fern (6/0 USNM). As above, lake shore litter under mint and jewelweed (1/1 USNM). As above, litter under fern and
jewelweed, shore of Lake Myosotis, in protected southern bay, 74-08-24 (0/1 USNM). S. Westerlo: Bear Swamp,
sphagnum, 74-08-14, W.R. Suter (1/1 USNM). Bronx Co.: Mosholu, no date, no collr. (1/0 CU). Erie Co.: 4 mi. N.
Alden, moss on Willow buttress, wamp, dried, 74-08-07, W.R. Suter (0/1 USNM). Monroe Co.: Rochester, no date,
K.W. Cooper (0/1 FNY). Niagara Co.: Olcott, 21-07-06, H. Dietrich (0/1 CU). Onondaga Co.: No site, 41-10-15,

N.M. Downie (3/2 NMD). Richmond Co.: Staten Island, no date, no collr. (1/4 CAS; 8/5 CU). St. Lawrence Co.:

Rossie, 63-08-19, N.M. Downie (1/0 NMD). Suffolk Co.: Long Island, no date, Wintersteiner (3/1 CU). Tompkins
Co.: Ithaca, 15-04-14, no collr. (1/0 CU). As above, 15-04-29 (1/1 CU). Ringwood Res., 64-04-18, P. Wood (1/0 CU).
Ithaca, Ringwood, no date, H. Dietrich (0/4 CU). Ulster Co.: Ludlow, no date, no collr. (1/0 CAS). Unspecified Co.:
No site, no date, no collr. (1/0 USNM). Arnot Forest, no date, R.D. Harwood (1/0 CU). Pennsylvania: Unspecified
Co.: No site, no date, no collr. (1/0 AMNH). Rhode Island: Washington Co.: Rockville, sphagnum. Eel Pond (bog),
61-07-04, Suter, Wagner and Reichle (0/1 WRS). Vermont: Bennington Co.: No site, no date, no collr. (1/0 USNM;
1/0 CU). Lamoille Co.: Lake of the Clouds on Mount Mansfield, 59-06-19, F.N. Young (1/0 FNY). Windsor Co.:
Woodstock, no date, no collr. (0/2 CU). Unspecified Co.: No site, no date, no collr. (1/0 USNM: 1/0 CAS). Virginia:
Highland Co.: Head waters, Colombia Union College Field Station, 66-07-27, P.J. Spangler (4/5 USNM). Wisconsin:

Kenosha Co.: Salem, Van Halter Bog, sphagnum, 67-09-16, W.R. Suter (1/0 WRS). Salem, Van Halter Bog,

Sphagnum, 69-09-01, W.R. Suter (2/4 USNM). 3 mi. NW Somers, mosses, Holmes Woods, 74-04-17 (0/1 USNM).
Salem, Van Halter Bog, Sphagnum, 74-02-19, W.R. Suter (0/1 USNM). 3 mi. NW Somers, Holmes Woods, mosses,
73-03-28, W.R. Suter (2/3 USNM). Marinette Co.: Harvey Cr., 70-08-24, John L. Heilman (0/1 JLH). Marquette
Co.: Endeavor, Sphagnum bog, 61-04-10, W.R. Suter (2/2 WRS). Sauk Co.: Sauk City, 1899-08-09, no collr. (1/0
US). Sauk City, 1899-08-05, no collr. (1/0 MCZ). Waushara Co.: S. Br. Wedde Cr., 70-08-13, John L. Heilman (1/0
JLH). Soules Cr., 70-08-13, John L. Heilman (0/1 JLH). Unspecified Co.: No site, no date, no collr. (1/0 CU; 0/3
USNM).

16. Hydraena ancylis new species

Map: Figure 25D
Paratypes: 21

United States: Indiana: Monroe Co.: Bloomington, Z. Pond 144a, 61-07-01, D.P. Wooldridge (5/1 DPW). Beech
Flats N. of Bloomington, 55-07-12, F.N. Young (1/0 FNY). Louisiana: Madison Co.: Tallulah, 30-12-08, P.A. Glick
(1/0 USNM). Missouri: Boone Co.: Silver Fork St., St. 5, 76-07-16, no collr. (1/1 USNM). Pennsylvania: York Co.: 5
mi. NW Davidsburg, 62-07-07, P.J. Spangler (2/5 USNM). Same, 72-09-03, P.J. Spangler & P.D. Perkins (1/0 PDP).
Texas: Hardin Co.: Saratoga, Ghost Road, Sphagnum, 72-06-11, W. Suter (1/2 PDP).

Western Hemisphere Hydraenidae

493

17. Hydraena vandykei d’Orchymont

Map: Figure 23C
Specimens examined: 378

Canada: British Columbia: Victoria, Vancouver, no date, no collr. (1/3 MCZ).

United States: California: Alameda Co.: San Ramon Creek, 51-07-12, PS. Bartholomew (1/0 CAS). Dimond,
60-05-15, F.E. Blaisdell (1/0 CAS). Contra Costa Co.: Berkeley, 19-11-11, H. Dietrich (10/16 CU). Perkins Gulch, 7
mi. SE Clayton, 66-07-22, J. Doyen (27/26 UCB). Hills back of Oakland, 08-06-07, no collr. (1/0 CAS). Berkeley,
47-10-28, D. Giuliani (1/0 CAS). Mt. Diablo, 19-09-21, J.O. Martin (1/0 CAS). Humboldt Co.: Conley Creek, 0.8 mi.
SE Blocksburg, 1350’, 68-07-19, H.B. Leech (1/5 CAS). N. Fork Yager Cr. at Bridgeville-Kneeland Rd., 1300',
66-08-08, H.B. Leech (0/2 CAS). Toss-up Creek, confluence with Redwood Creek, 2.5 mi. N. of road to Hoopa, ca
650', 70-08-13, H.B. Leech (6/4 CAS). Mill Cr., 7/5 mi. S. of Bridgeville, 1200’, 68-07-19, H.B. Leech (0/3 CAS).
Stream under Bair Rd., trib. to Pine Cr., W. of Hoopa, 3300’, 70-08-14, H.B. Leech (0/1 CAS). N. Fork Mad River at
Route 299, NE of Korbel, 525’, 70-08-30, H.B. Leech (1/0 CAS). Burr Cr., 3 mi. S. Bridgeville, 1200’, 68-07-19, H.B.
Leech (1/0 CAS). Lake Co.: No site, no date, no collr. (0/1 USNM). Barlett Sprs., no date, no collr. (0/1 CU; 0/1
MCZ). Lucerne, foul pool, dried bed of Cottage City Creek, 55-07-30, H.B. Leech (8/19 CAS). Headwaters, Long
Valley Cr., 3750’ 55-08-01, H.B. Leech (0/1 CAS). Middle Cr., 5 mi. N. Upper Lake, 55-08-04, H.B. Leech (0/1
CAS). Scott Cr., 2.75 mi. S. Lower Blue Lake, 55-08-05, H.B. Leech (0/1 CAS). Kelsey Cr., Kelseyville, 49-05-29,
H.B. Leech (0/2 CAS). Rice Fork of Eel River at Crabtree Hot Spring, 57-08-09, H.B. Leech (1/0 CAS). 6.9 mi. N.
Middletown, on hwy. 29, R.A. Badger Ranch, ephemeral stream, 55-02-20, H.B. Leech (1/2 CAS). Creek behind
Cottage City Resort, 53-07-05, H.B. Leech (1/0 CAS). Los Angeles Co.: Big Rock Cr., San Gabriel Mts., 59-03-31,
P.H. Raven (1/0 CAS). Pasadena, 17-01-28, J.O. Martin (1/2 CAS). As above, 17-09-06 (0/2 CAS). As above,

18- 09-02 (2/2 CAS). San Gabriel Canyon, 46-04-16, G.P. Mackenzie (1/0 UCR). Mts. nr. Claremont, no date, no
collr. (2/2 CMP). Claremont, no date, C.F. Baker (0/4 CFMNH). Pomona Mts., no date, no collr. (1/1 MCZ). Los
Angeles, no date, no collr. (0/2 MCZ). Mts. nr. Claremont, no date, Baker (0/1 MCZ). No site, no date, Koebele (1/0
USNM). Marin Co.: No site, 19-11-08, H. Dietrich (0/1 USNM). No site, 19-11-08, H. Dietrich (1/4 CU). Fairfax,
no date, F.E. Blaisdell (1/2 CAS). Mill Valley, 51-07-09, P.S. Bartholomew (1/0 CAS). Mill Valley, Cascade Cr.,
52-05-11, H.B. Leech (1/0 CAS). As above, 52-05-13 (1/1 CAS). As above, 52-03-29, H.B. Leech (0/1 CAS). L.
Lagunitas, 58-12-23, D.C. Rentz (0/1 CAS). Mill Valley, Falls Cr., 57-04-25, H.B. Leech (1/0 CAS). Lagunitas Cyn.,

19- 1 1-08, J.O. Martin (2/2 CAS). Lake Lagunitas, 19-1 1-01, no collr. (1/2 CAS). Carson Ridge, Woodacre, 56-01-09,
H.B. Leech (4/3 CAS). Tocaloma, pool at culvert, 68-05-04, H.B. Leech (8/9 CAS). Mariposa Co.: Miami Ranger
Station, 5000’, 42-07-06, H.P. Chandler (0/1 CAS). Mendocino Co.: Eel River R.S., 53-08-14, P.S. Bartholomew (1/0
CAS). Hendy Woods S.P., 58-06-14, L.N. & C.J. Bell (1/0 CAS). Mill Creek just W. of Mailliard, Redwoods State
Park, 64-09-06, H.B. Leech (2/0 CAS). Twin Rocks, 29-07-10, no collr. (4/8 CAS). Williams Creek at
Covelo-Paskenta Rd., 68-07-17, H.B. Leech (0/1 CAS). Beebe Cr., 50-09-05, H.B. Leech (0/1 CAS). Eel River N. of
Potter Valley, 50-09-02, H.B. Leech (0/1 CAS). Mendocino, 57-07-21, J.R. Heifer (0/1 CAS). Rancheria Cr., 5.5 mi.
SE Boonville, 50-06-15, H.B. Leech (0/1 CAS). Bloody Run Creek, 7 mi. E. of route 101, on Longvale-Covelo Road,
1100’, 68-07-18, H.B. Leech (3/4 CAS). Parson Creek, 4.5 mi. NE Hopland, 64-06-30, H.B. Leech (9/6 CAS).
Monterey Co.: Escondido, 73-05-19, J.E. Cronin (1/1 JEC). Napa Co.: 6 mi. NE Rutherford, 71-07-16, P.D. Perkins
(3/6 PDP). San Bernardino Co.: L. Arrowhead, 43-07-26, G.P. Mackenzie (1/1 AMNH). L. Arrowhead, 43-07-25,

G. P. Mackenzie (1/0 UA). San Mateo Co.: No site, no date, A. Koebele (1/0 USNM). La Honda, 26-07-14, P.S.
Bartholomew (0/1 CAS). Santa Barbara Co.: Santa Barbara 2300’, no date, F. Winters (2/1 CU). Santa Inez Mts., no
date, no collr. (0/1 CAS). Santa Cruz Island, 70-09-19, P.D. Perkins (1/0 PDP). Santa Clara Co.: Los Gatos, no date,
Hubbard & Schwarz (0/1 USNM). Los Gatos, 67-10-27, A. & A. Gillogly (1/0 AG). Alma, 27-08-01, J.O. Martin
(1/3 CAS). Santa Cruz Co.: Santa Cruz Mts., no date, no collr. (1 /3 CAS). Santa Cruz Mts., no date, A. Koebele (0.2
USNM). Sonoma Co.: Duncan Mills, no date, no collr. (0/2 USNM). Duncan Mills, 08-07-14, F.E. Blaisdell (/3 CU).
Calistoga, 34-06-12, Bryant (3/5 CAS). Rio Nido, 47-07-06, D. Giuliani (0/1 CAS). Duncan Mills marsh, 69-07-21, P.
Rubtzoff (0/2 CAS). Duncan Mills, 08-07-14, no collr. (3/1 CFMNH). Austin Cr., 2 mi. S. Cazadero, 54-10-30, H.B.
Leech (1/0 CAS). Mark West Cr. at Calistoga Rd., ca 4 mi. S. Petrified Forest, 63-07-08, H.B. Leech (4/2 CAS).
Camp Meeker, 52-07-10, P.S. Bartholomew (6/2 CAS). Guerneville, 08-07-14, F.E. Blaisdell (0/1 CAS). As above,
08-07-23, (1/0 CAS). Tehama Co.: Dead Mule Spr., 3 km by road N. of Paskenta-Covelo Rd., 1570 m, 72-08-29, H.B.
Leech (1/1 CAS). Trinity Co.: Van Horn Cr., 1.5 mi. above its mouth at upper Mad River, clear water pools in gravel
and stones of otherwise dry and shaded creekbed, 2850’, 70-08-09, H.B. Leech (3/9 CAS). Salt Cr. at Peanut,
60-08-01, H.B. Leech (0/1 CAS). Mad River at route 36, nr. Mad River Park, 68-07-20, H.B. Leech (1/1 CAS).
Hayfork Cr., 1.5 mi. S. of its East Fork, on Solidage flowers, 838 m, 72-08-08, H.B. Leech (0/1 CAS). Hayfork Cr. at
Hayfork-Wildwood Road, 70-08-1 1, H.B. Leech (2/1 CAS). S. Fork Van Horn Creek, 2 mi. from mouth at Upper Mad
River, moss-edged rock pools in running stream, open area, 70-08-09, H.B. Leech (4/1 CAS). Bridge Gulch Cr. at
Natural Bridge, 7.5 mi. airline N. Wildwood, 70-08-10, H.B. Leech (2/0 CAS). Mad River, 6 mi. S. Ruth, 60-07-31,

H. B. Leech (4/2 CAS). Unspecified Co.: No site, no date, no collr. (1 /0 CFMNH).

Quaest. Ent., 1980, 16 (1,2)

494

Perkins

18. Hydraena sierra new species

Map: Figure 23F
Paratypes: 16

United States: California: Fresno Co.: Stream from E. entering S. fork San Joaquin River, at gauging station by N.
end Jackass Dike, N. of Florence Lake, 7200’, 71-08-31, H.B. Leech (0/6 CAS). Madera Co.: Same data as Holotype
(5/2 CAS). Nevada Co.: Graniteville, 52-08-22, P.S. Bartholomew (1/0 CAS). Tulare Co.: Sequoia Nat. Park, no date,
F.E. Winters (1/0 CU). Oregon: Multnomah Co.: Portland, no date, Hubbard & Schwarz (1/0 USNM).

1 9. Hydraena leechi new species

Map: Figure 34A
Paratypes: 180

Mexico: Chihuahua: 30 mi. NW Chihuahua, Majalca Rd., 5500’, 61-04-14, Howden and Martin, (1/0 CNC).
Tamaulipas: 2 mi. SW Ciudad Victoria, stream in desert, 74-07-27, M.E. & P.D. Perkins (1 /0 PDP).

United States: Arizona: Cochise Co.: Sunnyside Cyn., W. side Huachuca Mts., 6000', 52-08-04, H.B. Leech, (14/5
CAS). E. of Cochise Stronghold, 70-09-18, P. Bartholomew, (0/1 CAS). Dry Cn. Sands Ranch, SE end Whetstone
Mts., 52-08-10, H.B. Leech, (2/2 CAS). Bisbee, 33-03-25, Bryant, (0/1 CAS). Hot Springs, no date, Barber and
Schwarz, (0/3 USNM). Chiric. Mts., no date, Hubbard & Schwarz, (0/1 USNM). Chiric. Mts., no date, no collr. (0/2
CU). Huachuca Mts., Garden Canyon, 50-06-23, C.P. Alexander, (0/1 MCZ). Cochise Stronghold, black light,

71- 09-25, D.S. Chandler, (1/0 UA). Coconino Co.: Oak Cr. Canyon, Midgley Bridge, 52-08-25, H.B. Leech, (23/21
CAS). Gila Co.: Globe, 48-10-13, F.H. Parker, (4/2 CAS). As above, (0/1 UA). Globe, Pinal Creek, 4000’, 53-04-24,
A. & H. Dietrich, (1/0 CU). Pima Co.: Santa Catalina Mts., Bear Canyon HH. mi. 11, B.L. trap. 59-07-09, F.G.
Werner, K.W. Radford, & G.A. Samuelson, (0/1 UA). Santa Catalina Mts., Pepper Sauce Cyn., B.L. trap, 61-07-08,
P.H. Johnson, (0/1 UA). Sabino Cyn., Catalina Mts., 55-11-27, G.D. Butler & F.G. Werner (1/1 UA). 2 mi. NW
Arivaca, in moss and grass roots along stream, 72-01-03, D.P. Levin & D.S. Chandler, (2/3 UA). 2 mi. NW Arivaca,
under bark of dead cottonwood, 72-03-29, D.S. Chandler, (1/1 UA). As above, in moss and grass roots along stream,

72- 02-06, (0/1 UA). As above, collected along creek edge, 71-11-13, (0/3 UA). Pinal Co.: Riverside, no date,
Wickham, (1/1 USNM). Santa Cruz Co.: Nogales, no date, no collr., (4/3 CAS). Sycamore Cyn., pools, cr. bed below
Yank’s Spring, Tumacacori Mts., ca 4000', 65-07-27, H.B. Leech, (2/1 CAS). Santa Rita Mts., Madera Cyn.,
70-09-01, D.G. Marqua & P.H. Sullivan, (1/1 PDP). Nogales, 06-09-07, F.W. Nunenmacher, (1/1 CU). As above,
(1/1 CFMNH). 15 mi. NW Nogales, Pena Blanca Lake, 61-05-26, Howden & Martin, (3/2 CNC). Sycamore Cyn. nr.
Ruby, 55-11-20, F.G. Werner & G.D. Butler, (3/6 UA). Florida Cyn., Santa Rita Mts., 59-04-19, F.G. Werner, (1/0
UA). Oklahoma: Johnston Co.: Pennington Cr., Tishomingo, 62-06-30, H.P. Brown, (1/1 PDP). Pennington Cr., Devil’s
Den, 72-07-25, H.P Brown, (0/1 PDP). Murray Co.: Honey Cr., Turner Falls, 68-08-23, H.P. Brown, (0/1 PDP).
Texas: Brewster Co.: Big Bend N. P., Pulliam Canyon, 45-6500’, 59-05-12, W.R.M. Mason, (4/0 CNC). Big Bend
N.P., Boot Spring, 7000’, 59-05-18, Howden and Becker, (3/1 CNC). Big Bend N.P., Glenn Springs, 72-03-23, H.P.
Brown, (1/1 PDP). Culberson Co.: 2.5 mi. E. of Nickel Creek Sta., 52-09-02, B. Malkin & V.E. Thathcre, (1/0
CFMNH). Jeff Davis Co.: Limpia Creek Canyon, Davis Mts., 52-09-04, B. Malkin, (14/17 CFMNH). Limpia Creek,
74-06-26, H.P. Brown (0/1 PDP).

20. Hydraena breedlovei new species

Map: Figure 166
Paratypes: 34

Mexico: Durango: Same data as Holotype (14/18 CAS). 9 mi. E. Los Bancos, ca 90 mi. W. Durango, stream, pine
forest meadow, 74-07-17, M.E. & P.D. Perkins (1/0 PDP). 1 mi. E. Los Bancos, ca 98 mi. W. Durango, stream in pine
forest, 74-07-17, M.E. & P.D. Perkins (1/0 PDP).

2 1 . Hydraena arizoniea new species

Map: Figure 34A
Paratypes: 47

Mexico: Durango: Los Altares, ex under stones in small creek in moutains, 2500 m, 74-10-10, H. & B. Reichardt
(1/0 MSP).

United States: Arizona: Cochise Co.: Sunnyside Cyn., W. side Huachuca Mts., 6000’, 52-08-04, H.B. Leech (12/5
CAS). Chiricahua Mts., above Herb Martyr, 74-06-22, H.P. Brown (2/1 PDP). Rustler's Park, 56-07-08, F.N. Young

Western Hemisphere Hydraenidae

495

(4/1 FNY). Santa Cruz Co.: Santa Rita Mts., Madera Cyn., 6200’, H.B. Leech (2/4 CAS). Madera Cyn., collected
along creek edge, 71-1 1-20, D.S. Chandler, (5/8 UA). Santa Rita Mts., 34-10-21, Bryant (0/1 CAS). Santa Rita Mts.,
no date, Hubbard & Schwarz (1/0 USNM).

22. Hydraena bituberculata new species

Map: Figure 34B
Paratypes: 52

United States: Arizona: Cochise Co.: Southwest Research Station, 64-10-24, P.H. Arnaud, Jr. (5/4 CAS). 3.5 mi.
SW Portal, Chiricahua Mts., 5000’, 52-08-13, H.B. Leech (0/1 CAS). Chiric Mts., no date, Hubbard & Schwarz (9/2
USNM). Chiricahua Mts., above Herb Martyr, 74-06-22, H P. Brown (1/1 HPB). Rustler’s Park, spring, 56-07-08,
F.N. Young (15/11 FNY). Chiricahua Mts., Rucker Cyn., 1730-1760 m., stream banks, 76-07-22, P.M. Hammond
(2/0 BMNH). New Mexico: Dona Ana Co.: Organ Mts., no date, no collr. (1 / 0 CU).

26. Hydraena alternata new species

Map: Figure 34B
Paratypes: 27

Mexico: Durango: 9 mi. E. Los Bancos, ca 90 mi. W. Durango, stream, pine forest meadow, 74-07-17, M.E. & P.D.
Perkins (0/1 PDP). Los Altares, ex under stones in a small creek in the mountains, 2500 m, 74-10-10, H. & B.
Reichardt (8/8 MSP; 5/5 PDP).

42. Hydraena ozarkensis new species

Map: Figure 42B
Paratypes: 61

United States: Indiana: Monroe Co.: Stephens Creek in T-9-N, R-l-E, Sec 20, 704, 50-06-23, F.N. Young (1/4
FNY). Parke Co.: 4 mi. W. Rockville, Hajji Hollow, air-4:45-5:l 5 PM, 71-08-14, H.S. Dybas (1/1 CFMNH).
Missouri: Boone Co.: 5 miles S. Columbia, 54-04-19, P.J. Spangler (0/1 USNM). Cape Giarardeau Co.: Cape
Girardeau, La Croix Creek, 53-09-11, P.J. Spangler (3/8 USNM). Cape Girardeau, 54-05-10, D. Stout (1/0 USNM).
Dallas Co.: Bennett Springs, 56-07-07, P.J. Spangler (1/6 USNM). Greene Co.: 3 mi. E. Springfield, Sac River,
56-04-13, P.J. Spangler (3/5 USNM). McDonald Co.: Rush Creek, 2 mi. E. Jane, 72-08-08, P.D. Perkins (4/8 PDP).
Ripley Co.: Doniphan, 56-04-23, no collr. (0/2 USNM). Oklahoma: Wagoner Co.: 14 mi. E. Wagoner, 64-06-20, P.J.
Spangler (5/5 USNM). Tennessee: Humphreys Co.: Near Buffalo, 62-07-20, F.N. Young (0/2 FNY).

46. Hydraena particeps new species

Map: Figure 59
Paratypes: 22

Grenada: Mount Gay Est. (Leeward side), no date, H.H. Smith (2/1 BMNH).

Honduras: Choluteca: 10 mi. W. Choluteca, 65-07-29, P.J. Spangler (1/0 PDP).

Panama: Panama: Madden L. near dam, pocket of damp leaves in dry streambed, 59-02-15, H.S. Dybas (4/4
CFMNH). Canal Zone: Albrook Forest Site, B-light, 68-01-31, R.S. Hutton (2/1 PDP).

Trinidad: Base of Galeota Pt., 35-09-20, N.A. Weber (2/2 MCZ).

Venezuela: Portuguesa: Guanare, 57-09-10, B. Malkin (1/2 CAS).

48. Hydraena guadelupensis d’Orchymont

Map: Figure 59
Specimens examined: 59

Costa Rica: Reventazon, Hamburg Farm, sifted from swamp litter, 33-08-07, F. Nevermann (1/0 USNM).

Jamaica: Moneague, 34-08-26, Darlington (1/2 MCZ). Ocho Rios, 34-08-20, Darlingon (2/4 MCZ). Porus, sta.
414, Hying at dusk, 37-02-23, Chapin & Blackwelder (14/28 USNM). Milk River, 37-02-25, Chapin and Blackwelder
(0/1 USNM). Bog Walk, 37-02-02, Chapin & Blackwelder (0/3 USNM). Hope River, 18-05-26, M. Cameron (1/0
BM). St. Catherine, Bushy Park, 47-02-09, ex. small pool in narrow gully, G.B. Thompson (1/1 10J).

Virgin Islands: St. John, Cinnamon Bay, spring, 63-01-23, P.J. Spangler & D. Zani (15/45 USNM).

Quaest. Ent., 1980, 16 (1,2)

496

Perkins

49. Hydraena spongier i new species

Map: Figure 56B
Paratypes: 150

United States: Florida: Alachua Co.: Wacahootee, 39-10-12, F.N. Young (1/1 FNY). Island Grove at Orange
Lake, debris at swamp edge, yellow poplar, palms, 65-08-22, H.R. Steeves (1/0 CFMNH). Collier Co.: Monroe Sta.,
2.5 mi. E., hardwood hammock along Tamiami Trail, 66-04-07, J. Wagner (10/5 CFMNH). Dade Co.: Everglades
Natl. Park, Palm Vista Hammock, 65-08-27, W.R. Suter (3/0 CFMNH). Everglades Natl. Park, Mahogany
Hammock, Palmetto-Mahogany Swamp, 65-06-18, W.R. Suter (7/9 CFMNH). Highlands Co.: Venus, 4 mi. W„
Fisheating Creek, under water hyacinth, 73-12-30, W.R. Suter (2/3 USNM). Venus, 4 mi. W., Fisheating Creek,
grassy compost mixed with Cypress needles on bridge approach, 65-08-25, W.R. Suter (3/0 CFMNH). Hammock State
Park, Magnolia buttress, 66-04-06, W.R. Suter (1/0 CFMNH). Jackson Co.: Marianna, 3 mi. NW„ litter in sinkhole,
68-09-08, S. Peck (1/0 CFMNH). Leon Co.: Chaires, 65-08-29, W.R. Suter (0/1 CFMNH). Sarasota Co.: Myakka
River State Park, Fla. rt. 72, Palmetto-oak pocket, 65-06-16, W.R. Suter (2/0 CFMNH). Volusia Co.: lake Helen
(vicinity), berlese, litter, 69-04-10, W.R. Suter (3/3 CFMNH). Georgia: Glynn Co.: St. Simon’s Island, Brunswick,
77-06-19, Hoffman (2/0 PDP). Louisiana: Madison Co.: Tallulah, no date, no collr. (1/0 PDP). Maryland:
Montgomery Co.: Plummer’s Island, 60-06-06, P.J. Spangler (16/28 USNM). As above, 60-09-01, (3/3 USNM). As
above, 72-04-19, (1/0 USNM). C. & O. Lock at Plummer’s Island, 60-06-29, P.J. Spangler (1/3 USNM). As above,
61-06-07, (9/16 USNM). Talbot Co.: Easton, 73-07-29, Spangler & Cross, (4/3 USNM). Easton, Seth State Forest,
76-05-13, Spangler et al. (30/48 USNM). Mississippi: George Co.: Pool 6 mi. W. Pascagoula R., 60-06-17, F.N. Young
(1/2 FNY). Oklahoma: Carter Co.: 5 mi. E., stump berlese, 68-07-09, W. Suter (1/0 USNM). South Carolina:
Bramberg Co.: No site, 66-11-20, R.E. Widdows (1/1 CFMNH). Berkeley Co.: No site, 66-10-13, R.E. Widdows (2/1
CFMNH). Charlestown Co.: No site, 66-10-13, R.E. Widdows (1/0 CFMNH). Sumter Co.: Sumter, 66-10-29, R.E.
Widdows (1/0 CFMNH). Texas, Hardin Co.: Saratoga, Ghost Road, sphagnum, 72-06-11, W. Suter (1/2 USNM).
Virginia: Hampton Co.: Fort Monroe, no date, no collr (0/1 PDP).

50. Hydraena punctata LeConte

Map: Figure 42B
Specimens examined: 24

United States: Connecticut: Fairfield Co.: No site, no date, no collr. (2/0 CU). Massachusetts: Middlesex Co.:
Drac, 1890-08-02, no collr. (2/2 CMP; 1/2 MCZ). Drac, no date, no collr. (1/1 MCZ; 0/1 BMNH). Tyngsboro, no
date, no collr. (2/1 MCZ; 0/1 BMNH). Unspecified Co.: No site, no date, no collr. (2/1 CMP; 0/1 MCZ). New
Jersey: Bergen Co.: Westwood, no date, no collr. (0/1 AMNH). New York: Tompkins Co.: Ithaca, Fall Creek, Stewart
Park, A. d’Orchymont (0/1 1SNB). Ulster Co.: Esopus, no date, no collr. (1/0 CU). Unspecified Co.: Totowa, no date,
Wintersteiner (1 /0 CU).

5 1 . Hydraena oblio new species

Map: Figure 59
Paratypes: 13

Guatemala: Baja Verapaz: Same data as Holotype (2/2 PDP). Chiquimula: 4 mi. N. Quezaltepeque, madicolous
habitat, 74-06-17, M.E. & P.D. Perkins (0/2 PDP). Huehuetenango: 6 mi. NW Huehuetenango, stream in oak-pine,
74-06-29, M.E. & P.D. Perkins (0/1 PDP).

Mexico: Chiapas: Jet. Rts. 190 & 195, 69-06-1 1, J.M. Cambpell (3/3 CNC).

57. Hydraena prieto new species

Map: Figure 42A
Paratypes: 29

Mexico: Durango: Same data as Holotype (16/10 PDP). Los Altares, 2500 m, ex. under stones in a small creek in
the mountains, 74-10-10, H. & B. Reichardt (1/1 MSP). Jalisco: 7 mi. S. Mazamitla, 48-12-01, H.B. Leech (1/0
CAS).

Western Hemisphere Hydraenidae

497

61. Hydraena cuspidicollis new species

Map: Figure 42A
Paratypes: 72

Mexico: Colima: 29 mi. NE (by road) of Colima, 48-12-03, H.B. Leech (0/18 CAS). Jalisco: 7 mi. S. Mazamitla,
stream in pine forest, 74-07-15, M.E. & P.D. Perkins (0/1 PDP). Mexico: 11 mi. S. Valle de Bravo, stream in
deciduous-pine forest, 74-07-12, M.E. & P.D. Perkins (0/20 PDP). San Antonio, 8000-10,000’, 66-10-11, H.P. Brown
(0/22 HPB). Temescaltepec, Real de Arriba, 6-7000', 34-07-01, H.E. Hinton & R.L. Usinger (0/3 BMNH). As above,
1932 (0/1 BMNH). Oaxaca: Same data as Holotype (2/4 PDP). Veracruz: 1.2 mi. S. Huatusco, cloud forest litter,
berlese, 1344 m, 68-08-02, S. & J. Peck (0/1 CNC).

68. Hydraena mexicana new species

Map: Figure 42A
Paratypes: 5

Mexico: Chiapas: Same data as Holotype (1/0 PDP). San Luis Potosi: Same data as Allotype (2/0 CAS).
Veracruz: Cordoba, no date, A. Fenyes (1/1 CAS).

74. Hydraena hyalina new species

Map: Figure 92A
Paratypes: 70

Brazil: Bahia: 5 km W. Ilheus, 69-07-04, P. & P. Spangler (1/3 USNM).

Guyana: British Guiana, nr. Lethem, Rupununi, weeds on mud of drying pond in Savannahs, 61-02-02, T. Clay
(5/3 BMNH). Brit. Guiana, Kanuku Mts., Rupununi, debris edge of forest creek, 61-02-21, T. Clay (1/3 BMNH).

Venezuela: Guarico: 15 km S. Calabozo, coll’d, in Lago de Los Patos, 69-02-09, P. & P.J. Spangler (26/23
USNM). 32 km SW Calabozo, 69-02-11, P. P.J. Spangler (3/1 USNM). Barinas: 10 km NE Barinas, 69-02-23, P. &
P.J. Spangler (0/1 USNM).

77. Hydraena insularis d’Orchymont

Map: Figure 172A
Specimens examined: 1

Dominica: 2 mi. NW Pont Casse, 64-10-05, P.J. Spangler (1/0 USNM).

78. Hydraena marginicollis Kiesenwetter

Map: Figure 56A

Specimens examined: 177

United States: Alabama: Houston Co.: Chattachoochee Park, creek, 54-06-06, S.N. Brown, F.N. Young (0/1
DPW). Macon Co.: 0.5 mi. E. of Line Cr. on interstate hwy. 85, 67-11-11, G.W. Folkerts (1/0 GWF). Mobile Co.:
Mobile, no date, no collr. (2/2 MCZ). Mobile, no date, H.P. Loding (0/1 MCZ). Arkansas: Randolph Co.: 1 mi. N.
Maynard, at light in Oak-Maple-Walnut-Juniper woods, 67-08-05, H.B. Leech (0/1 CAS). Florida: Alachua Co.:
Payne’s Prairie, nr. Gainesville, emergent vegetation at lake shore, 73-08-23, P.D. Perkins (3/3 PDP). 2 mi. N. Santa
Fe, small pools adjacent to reservoir, 73-05-21, P.D. Perkins (2/5 PDP). Gainesville, Green Sink, 39-09-25, F.N. Young
(0/2 BMNH). Gainesville, Greek Sink, 37-03-08, F.N. Young (1/2 FNY). No site, no date, no collr. (4/1 CU).
Charlotte Co.: Punta Gorda, 11-11-16, no collr. (0/1 AMNH). Dade Co.: Miami Springs, at light, 62-08-02, B. Benesh
(1/0 CAS). Homestead, 51-06-11, Bryant (1/2 CAS). Duval Co.: Jacksonville, no date, no collr. (0/2 CU). Gadsden
Co.: Nr. Mt. Pleasant, Glen Julia Springs, 54-06-06, F.N. Young (1/0 DPW). Hendry Co.: 6 mi. S. LaBelle, litter
under water hyacinth at creek, 74-02-04, W.R. Suter (0/1 USNM). LaBelle, 18-02-26, W.S. Blatchley (0/1 AMNH;
3/0 PU). Highlands Co.: Archbold Bio. Station, at black light, 73-12-28, W.R. Suter (2/7 USNM). Venus, Fish Eating
Creek, 75-01-20, W.R. Suter (6/16 WRS). Sebring, 39-03-07, no collr. (0/1 AMNH). Sebring, 42-10-10, C. Parsons
(0/1 CAS). Hillsborough Co.: Tampa, no date, Hubbard & Schwarz (0/1 USNM). Tampa, no date, F.C. Bowditch
(0/1 MCZ). Okeechobee Co.: Okeechobee, 43-03-12, W. Proctor 91/0 CU). Okeechobee, 39-03-13, F.E. Lutz (5/0
AMNH). Palm Beach Co.: Royal Palm Park, 32-04-01, W.S. Blatchley (1/0 PU). L. Worth, no date, no collr. (0/1
AMNH). Pinellas Co.: Dunedin, 30-05-04, W.W. Blatchley (6/6 BMNH). Dunedin, 13-03-15, W.S. Blatchley (0/3

Quaest. Ent., 1980, 16 (1,2)

498

Perkins

NYSS). Dunedin, no date, no collr. (1/0 CAS). Dunedin, 29-02-21, W.S. Blatchley (3/4 CU). Dunedin, 13-01-22,
W.S. Blatchley (1/0 PU). As above, 17-12-23 (1/0 PU). As above, 16-12-21 (0-1 PU). As above, 14-01-03 (0/1 PU).
As above, 24-02-03 (0/1 PU). Haven, 22-03-23, W.S. Blatchley (0/1 PU). Dunedin, 18-03-17, W.S. Blatchley (2/1
UW). Putnam Co.: Cresent City, no date, Hubbard & Schwarz (2/3 USNM). Taylor Co.: No site, no date, no collr.
(1/2 CU). Volusia Co.: Enterprise, no date, F.C. Bowditch (0/4 MCZ). Enterprise, debris, lake shore, no date, no collr.
(0/1 CAS). L. Harney, no date, no collr. (1/0 CU). Unspecified Co.: No site, no date, no collr. (1/0 MCZ; 2/3 CU).
Georgia: Lowndes Co.: Valdosta, no date, no collr. (1/0 CU). Louisiana: East Baton Rouge Co.: Baton Rouge,
61-04-29, B. Monroe (0/1 LSU). Madison Co.: Tallulah, 29-09-05, P.A. Glick (0/1 USNM). Tallulah, 33-11-13,
Folsom (0/3 MCZ). New Jersey: Unspecified Co.: No site, no date, Wintersteiner (0/1 CU). North Carolina: Currituck
Co.: Knotts Island, 72-09-16, P.D. Perkins (10/10 PDP). South Carolina: Florence Co.: Florence, 54-07-22, V.M. Kirk
(2/0 VMK).

80. Hydraena pulsatrix new species

Map: Figure 56A

Paratypes: 32

Mexico: Tamaulipas: Ciudad Mante, 64-08-22, P.J. Spangler (1/1 USNM). Veracruz: 15 mi. SE Tantcyuca,
65-08-28, P.J. Spangler (1/0 USNM).

United States: Oklahoma, Marshall Co.: Willis, 1 mi. SE, floor, willow swamp, 68-07-06, W. Suter (1/0 USNM).
Texas: Cameron Co.: Brownsville, 33-06-11, Darlington (8/11 MCZ). Kinney Co.: Brackettsville, 72-03-21, H.P. Brown
(2/1 USNM). San Patricio Co.: 7.5 mi. N. Sinton, Welder Wildlife Foundation, mucky dead grass mat, margin of
small lake, 74-01-18, J.L. Bengston (2/0 USNM). Uvalde Co.: Garner St. Pk., Con Can Rio Frio area, Berlese,
streamside litter under cypress, 72-07-06, W. Suter (2/0 CFMNH). Val Verde Co.: Devil’s River, at light, 07-05-06,
Bishopp & Pratt (1/0 USNM). Unspecified Co.: No site, 72-11-22, J.L. Carr (0/1 JLC).

8 1 . Hydraena longicollis Sharp

Map: Figure 56A
Specimens examined: 15

Guatemala: Estancia Virgen, 65-08-12, P.J. Spangler (3/2 USNM). Same data as Lectotype (2/2 BMNH)
(labelled paralectotypes). Duenas, no date, no collr. (0/1 BMNH) (labelled paralectotype). Paso Antonio, 400’, no date,
no collr. (0/1 BMNH) (labelled paralectotype).

Mexico: Chiapas: Jet. Rts. 190-195, 69-06-1 1, J.M. Campbell (1/2 CNC).

Nicaragua: Chontales, no date, no collr. (0/1 BMNH) (labelled paralectotype).

83. Hydraena anisonycha new species

Map: Figure 50B
Paratypes: 1,714

Colombia: Cundinamarco: 11 km N. Bogota, 69-0 1 -( 1 -8), P. & P.J. Spangler (571/826 USNM). 5 km N. Bogota,
69-03-01, P. & PJ. Spangler (122/128 USNM). 12 km S. Tocancipa, 69-03-02, P. & P.J. Spangler (26/11 USNM).
Meta: 10 km S. Villavicencio, 69-03-03, P. & P.J. Spangler (14/16 USNM).

84. Hydraena colymba new species

Map: Figure 59
Paratypes: 55

Costa Rica: 8 mi. SE Liberia, 65-07-24, P.J. Spangler (2/2 USNM).

Guatemala: Jalapa: Same data as Holotype (15/20 PDP). Jutiapa: Jutiapa, 66-10-29, H P. Brown (1/0 USNM).
Honduras: Copan, in algae, rain pond, 55-09-08, B. Malkin (1/1 CAS). San Marcos Colon, 65-07-28, P.J. Spangler
(1/5 USNM).

Mexico: Chiapas: Jet. Rts. 190-195, 69-06-11, J.M. Campbell (3/1 CNC). As above, 69-06-06 (3/0 CNC).

85. Hydraena nevermanni new species

Map: Figure 173

Western Hemisphere Hydraenidae

499

Paratypes: 57

Costa Rica: Same data as Holotype (3/3 USNM). Hamburgfarm, Reventazon ebene Limon stehendem Wasser,
29-10-26, F. Nevermann (1/1 USNM). Reventazon, Hambergfarm, 33-01-28, Ferdinand Nevermann (21/28
CFMNH).

87. Hydraena pontequula new species

Map: Figure 173
Paratypes: 165

Panama: Canal Zone: Same data as Holotype (20 RTA; 20 PDP; 10 DCM; 10 USNM). As above, black light,
68-05-24 (5 RTA; 5 DCM; 5 USNM; 5 PDP). Rio Frijoles, 4.1 mi. NW Gamboa, berlese, wet leaves and flood debris
along river, 76-02-19, A. Newton (4/0 PDP). Panama: Madden L. near dam, berlese, damp pockets of leaves and debris
in streambed, 59-02-15, H.S. Dybas (44/36 CFMNH). As above, 59-02-06 (0/1 CFMNH).

88. Hydraena sabella new species

Map: Figure 59

Paratypes: 140

Guatemala: Izabal: 1 mi. N. Morales, 65-08-16, P.J. Spangler (7/48 USNM).

Mexico: Chiapas: 8 mi. W. Teapa, large tropical stream, 74-05-26, M.E. & P.D. Perkins (2/83 PDP).

3. Spanglerina brevis (Sharp)

Map: Figure 68B

Specimens examined: 232

Guatemala: Alta verapaz: 20 mi. W. La Tinta, rapid tropical stream, 74-06-07, M.E. & P.D. Perkins (1/32 PDP). 5
mi. W. La Tinta, small tropical brook, 74-06-06, M.E. & P.D. Perkins (0/86 PDP). Baja verapaz: 1 mi. S. San
Jeronimo, rapid stream in pines, 74-06-03, M.E. & P.D. Perkins (0/2 PDP). 4 mi. S. Rabinal, stream, transition
xeric-tropical, 74-06-10, M.E. & P.D. Perkins (0/7 PDP). Huehuetenango: 21 mi. NW Huehuetenango, 74-06-29, M.E.
& 4jD. Perkins (0/6 PDP). 7 mi. S. La Mesilla, slightly silty stream, 74-05-30, M.E. & P.D. Perkins (0/1 PDP). 35
mi. S. La Mesilla, tropical brook, 74-05-30, M.E. & P.D. Perkins (0/3 PDP). 26 mi. S. Rabinal, large stream with
boulders, 74-06-12, M.E. & P.D. Perkins (0/1 PDP). Jalapa: 10 mi. E. Guatamala City, 65-08-08, P.J. Spangler (0/1
USNM). Suchitepequez: 5 mi. N. Patulul, stream in bananna trees, 74-06-26, M.E. & P.D. Perkins (0/1 PDP).

Honduras: Morazan: 9 mi. N. Sabana Grande, rapid stream, 74-06-22, M.E. & P.D. Perkins (0/1 PDP).
Ocotepeque: 14 mi. N. Nueva Ocotepeque, rapid brook in dense vegetation, 74-06-18, M.E. & P.D. Perkins (0/30
PDP).

Mexico: Chiapas: 10 mi. S. Malpaso, 69-05-24, J.M. Campbell (2/1 CNC). nr. Ixtala, Rio Escopetazo, 66-12-03,
H.P. Brown (0/3 HPB). 9 mi. N. Tapilula, tropical stream, 74-05-27, M.E. & P.D. Perkins (0/2 PDP). 4 mi. N.
Bochil, stream in pine forest, 74-05-28, M.E. & P.D. Perkins (0/2 PDP). Colima: El Cobano, 70-03-25, H.P. Brown
(0/1 PDP). Guerrero: El Limon, 69-04-04, H.P. Brown (0/1 PDP). Oaxaca: 1 mi. N. Ixtlan de Juarez, stream in
oak-pine, 74-07-03, M.E. & P.D. Perkins (0/1 PDP). 4 mi. S. Valle National, cascading tropical brook, 74-07-06 (2/20
PDP). 8 mi. E. Tapanatepec, tropical stream with large boulders, 74-07-03, M.E. & P.D. Perskins (0/25 PDP).

Panama: Chiriqui: Bambito, small trib. of Rio Chiriqui, 66-1 1-17, H.P. Brown (0/1 PDP).

1 . Limnebius discolor Casey

Map: Figure 78B

Specimens examined: 216

United States: Indiana: Brown Co.: Caldwell’s Hollow near Belmont, 64-10-01, H. Clifford (3/5 FNY). Maryland:
Frederick Co.: Thurmont, C.F. St. Pk., 76-09-18, P.J. Spangler (7/3 USNM). Missouri: Reynolds Co.: Ellington, Logan
Cr., 56-08-19, P.J. Spangler (2/0 USNM). Pennsylvania: Potter Co.: Ole Bull St. Park, 66-08-20, P.J. Spangler (4/5
USNM). Virginia: Bath Co.: 12 mi. S. Williamsville, pebbly stream, 73-10-06, P.D. Perkins (92/95 PDP).

3. Limnebius ozapalachicus new species

Map: Figure 78B

Quaest. Ent., 1980, 16 (1,2)

500

Perkins

Paratypes: 300

United States: Kentucky: Ohio Co.: Fordsville, 72-08-12, P.D. Perkins (9/8 PDP). Maine: Penobscot Co.: Corinth,
69-07-22, S. Malcolm (1/0 DCM). Missouri: Cape Girardeau Co.: Cape Girardeau, La Croix Cr., 56-09-13, P.J.
Spangler (2/7 USNM). Same, 53-09-11 (19/20 USNM). Cape Girardeau, 54-05-10, D. Stout (1/0 USNM). 5 mi. S.
Columbia, 54-04-19, P.J. Spangler (2/3 USNM). Crawford Co.: Merrimac River, 54-11-21, P.J. Spangler (5/10
USNM). Same, 53-07-21 (3/3 USNM). Dallas Co.: Bennett Springs, 56-07-07, P.J. Spangler (2/2 USNM). Dent Co.:
5 mi. E. Salem, 55-10-10, P.J. Spangler (1/4 USNM). Greene Co.: 3 mi. E. Springfield, Sac River, 56-04-13, P.J.
Spangler (7/19 USNM). Madison Co.: Mine La Motte, 53-09-09, P.J. Spangler (6/0 USNM). Maries Co.: Vienna,
56-09-25, P.J. Spangler (15/31 USNM). McDonald Co.: Rush Cr., 2 mi. E. Jane, 72-08-08, P.D. Perkins (9/21 PDP).
10 mi. E. Anderson, 60-07-12, E. Todd (0/2 USNM). Reynolds Co.: Bunker, Sugar Creek, 56-08-08, P.J. Spangler
(1/0 USNM). Ellington, Logan Creek, 56-08-08, P.J. Spangler (3/0 USNM). Ripley Co.: Doniphan, Logan Creek,
56-04-23, P.J. Spangler (2/0 USNM). Oklahoma: Wagoner Co.: 14 mi. E. Wagoner, 64-06-20, P.J. Spangler (28/17
USNM). Tennessee: Humphreys Co.: Near Buffalo, 62-07-20, F.N. Young (5/9 FNY). Virginia: Bath Co.: 12 mi. S.
Williamsville, pebbly stream, 73-10-06, P.D. Perkins (11/10 PDP). West Virginia: Hardy Co.: 6 mi. SW Wardensville,
74-10-12, P.D. Perkins (2/0 PDP).

4. Limnebius piceus (Horn)

Map: Figure 76D
Specimens examined: 257

Mexico: Baja California: Baja California Norte, Arr. Santo Domingo, 5.7 mi. E. Hamilton Ranch, dam site,
63-04-23, P.H. Arnaud, Jr. (13/12 CAS). La Suerte, Sierra San Pedro Martir, pool in canyon, 3700', 63-06-04, R.K.
Benjamin (1/2 CAS).

United States: California: Calaveras Co.: Waterman Cr., 4.5 mi. W. of Altaville, Hwy, 4, 63-08-31, H.B. Leech
(2/1 CAS). Colusa Co.: Little Stony Cr., 6 mi. S. Stonyford, 56-03-29, H.B. Leech (1/1 CAS). Contra Costa Co.: Mt.
Diablo, 19-09-21, no collr., (1/0 CAS). Fresno Co.: Kings River Camp, 50-08-23, P.S. Bartholomew (8/11 CAS).
Glenn Co.: Trib. to Stony Cr., 7 mi. N. Stonyford, 56-03-29, H.B. Leech (1/1 CAS). Lake Co.: North Fork Cache Cr.
at Route 20, 312 m., 71-10-10, H.B. Leech (1/3 CAS). Los Angeles Co.: Pasadena, no date, H.C. Fall (1/0 CAS). Big
Rock Creek, San Gabriel Mts., 59-03-31, P.H. Raven (4/0 CAS). Los Angeles, no date, no collr. (2/3 USNM).
Monterey Co.: Carmel River, 50-08-20, P.S. Bartholomew (15/22 CAS). Carmel, 56-09-21, B. Malkin (1/0 CFMNH).
Same, 53-06-28 (8/7 CFMNH). Napa Co.: Soda Cr. at Highway 128, 64-08-30, H.B. Leech (1/0 CAS). Pope Cr. at
Walter Springs Rd„ 520’, 64-08-31, H.B. Leech (4/9 CAS). Same, 71-07-17, P.D. Perkins (9/20 PDP). Placer Co.:
Squaw Valley Cr., 55-06-25, P.S. Bartholomew (1/1 CAS). Riverside Co.: Palm Canyon, 16-04-15, J.O. Martin (1/0
CAS). Palm Springs, no date, Hubbard & Schwarz (1/1 USNM). San Jacinto Mts., no date, F.E. Winters (1/1 CAS).
Riverside, no date, F.E. Winters (1/1 MCZ). San Bernardino Co.: Mojave River near Victorville, 56-02-12, R.K.
Benjamin (5/3 CAS). Hesperia, 18-06-30, no collr. (4/5 CAS). San Diego Co.: Camp Pendleton, Oceanside, 45-10-26,
H.P. Chandler (19/23 CAS). Santa Barbara Co.: Santa Barbara, no date, F.E. Winters, (5/9 CAS). Cuyama River, ca
10 mi. E. Santa Maria, 52-07-21, H.B. Leech (2/3 CAS). Stanislaus Co.: Adobe Cr., 16 mi. W. of Patterson, 48-04-25,
H.B. Leech (2/2 CAS). Tulare Co.: Kaweah, no date, no collr. (1/0 CAS).

5. Limnebius alutaceus (Casey)

Map: Figure 76A
Specimens examined: 434

Canada: British Columbia: Copper Mtn., 30-10-12, G. Stace Smith (2/1 CAS; 9/9 UBC). Enderby, Shuswap
River, 46-10-11, H.B. Leech (6/5 CAS; 0/2 UBC). Salmon Arm, Salmon River, 46-10-13, H.B. Leech (1/0 CAS).
Lister, pond, 2000 feet, 37-08-12, G. Stace Smith (1/0 UBC). Creston, Goat River, 46-09-01, G. Stace Smith (1/0
MCZ). Cariboo Dist., Beedy Cr. at Gaston Rch., 30 mi. NE McLeese Lake, 71-07-25, P.D. Perkins (10/12 PDP).
Cariboo Dist., Beaver Cr., 40 mi. NE McLeese Lake, 71-07-28, P.D. Perkins (23/34 PDP).

United States: California: Colusa Co.: Indian Cr., 1.5 mi. along road to Cooks Springs, SW of Lodoga, 71-10-10,
H.B. Leech (1/0 CAS). El Dorado Co.: Rubicon River at Georgetown- Ralston Rd„ 63-07-27, H.B. Leech (1/0 CAS).
Glenn Co.: Trib. to Stony Cr., 7 mi. N. Stonyford, 56-03-29, H.B. Leech (1/5 CAS). Humboldt Co.: Hydesville, no
date, no collr., (1/0 CAS). Korbel, 16-06-16, F.E. Blaisdell (6/2 CAS). Bear River at Capetown, 65-10-01, H.B. Leech
(2/1 CAS). N. Fork Mattole River, NW of Petrolia, 65-10-02, H.B. Leech (1/2 CAS). Toss-up Cr., confluence with
Redwood Cr., 2.5 mi. N. of road to Hoopa, ca 650 ft., 70-08-13, H.B. Leech (2/1 CAS). Lake Co.: Creek behind
Cottage City Resort, Lucerne, 53-07-05, H.B. Leech (6/8 CAS). Bartlett Cr., Bartlett Springs, 55-08-01, H.B. Leech
(4/4 CAS). Middle Cr., 5 mi. N. of Upper Lake, 55-08-04, H.B. Leech (3/13 CAS). Headwaters, Long Valley Cr.,
3750 ft., 55-08-01, H.B. Leech (2/1 CAS). Los Angeles Co.: Pasadena, no date. Winters (1/0 CAS). Big Rock Cr., San
Gabriel Mts., 59-03-31, P.H. Raven (1/0 CAS). San Fernando, no date, no collr. (1/0 MCZ). Madera Co.: Jackass Cr.,

Western Hemisphere Hydraenidae

501

E. end Jackass Meadow, 6960 ft., 71-08-17, H.B. Leech (3/4 CAS). Mendocino Co.: Rancheria Cr., 2 mi. S. Yorkville,
tiny stream, 54-07-25, H.B. Leech (1/1 CAS). Rancheria Cr., 5.5 mi. SE Boonville, 50-06-15, H.B. Leech (1/2 CAS).
Middle Fork of Eel River, 0.3 mi. below mouth of Black Butte River, 1500’, 68-07-16, H.B. Leech (2/0 CAS). Eel
River, 4.5 mi. NW of Lanes Redwood Flat, 60-08-05, H.B. Leech (7/6 CAS). Navarro River, 2 mi. NW Philo, Hendy
Woods State Park, 64-07-22, P. Rubtzoff (2/1 CAS). Garcia River at Highway 1, 64-10-12, H.B. Leech (1/4 CAS).
Navarro River, 8 mi. W. Navarro, 50-06-15, H.B. Leech (3/0 CAS). Beebe Cr., 50-09-05, H.B. Leech (1/0 CAS).
Williams Cr. at Covelo-Paskenta Rd„ 70-10-17, H.B. Leech (1/1 CAS). Outlet Cr., 1 mi. ENE of Longvale Dos Rios
Rd., 70-08-07, H.B. Leech (1/1 CAS). Napa Co.: Pope Cr. at Walter Springs Rd., 520’, 640-08-31, H.B. Leech (4/0
CAS). 6 mi. NE Rutherford, 71-07-16, P. D. Perkins (1/0 PDP). Plumas Co.: Clio, on Middle Fork Feather River,
61-08-28, H.B. Leech (5/8 CAS). Chester, 14-10-15, R. Hopping (1/2 CAS). San Bernardino Co.: Lake Arrowhead,
44-07-24, G.P. Mackenzie (1/0 CAS). Santa Barbara Co.: Santa Barbara, no date, F.E. Winters (1/5 CAS). Santa
Clara Co.: Gilroy Hot Springs, 15-07-07, no collr. (1/0 CAS). San Martin, 52-06-26, P.S. Bartholomew (1/0 CAS).
Sierra Co.: Onion Cr., N. end Onion Valley, 60751, 64-10-21, H.B. Leech (1/0 CAS). Siskiyou Co.: Sugar Cr., 2.3 mi.
NW of Callahan, 66-08-17, H.B. Leech (1/0 CAS). Etna Cr., 1.5 mi. SW of Etna, 3100’, 70-08-20, H.B. Leech (1/3
CAS). No site, no date, A. Koebele (2/2 USNM). Sonoma Co.; Austin Cr., 2 mi. S. Cazadero, 54-10-30, H.B. Leech
(5/1 CAS). Austin Cr., 2.5 mi. up from its mouth, 64-09-28, H.B. Leech (1/0 CAS). Wheatfield Br. of Gualala River
at bridge, Annapolis & Stewarts Point-Healdsburg Rd., 64-09-07, H.B. Leech (1/1 CAS). Russian R., bank, 2 mi.
below Guerneville town, 64-09-28, H.B. Leech (4/2 CAS). Guerneville, 08-07-23, F.E. Blaisdell (1/0 CAS). Cloverdale,
26-06-19, V.S. Brown (1/0 CAS). Santa Rosa, 94-10-10, no collr. (1/0 UW). The Geysers, 70-09-07, P.D. Perkins (3/3
PDP). Trinity Co.: Mad River, 6 mi. S. Ruth, 60-07-31, H.B. Leech (4/8 CAS). Salt Creek at Peanut, 60-08-01, H.B.
Leech (2/2 CAS). Mad River just above mouth Van Horn Cr., 4.25 air miles SE of Ruth, 70-08-07, H.B. Leech (1/0
CAS). Tuolumne Co.: Jackass Cr., 4.2 mi. SE of Priest, on Coulterville Rd., 2100’, 62-08-19, H.B. Leech (1/0 CAS).
Niagara Cr., Forest. Campgd., 62-08-09, H.B. Leech (2/0 CAS). Pinecrest, 48-07-13, P.H. Arnaud (1/1 CAS). Blaine
Co.: Wood River, 69-09-10, Schuh, Phipps & Coulson (1/1 JS). Idaho: Lemhi Co.: Salmon R., 4 mi. N. Salmon,
71-08-03, P.D. Perkins (1/0 PDP). Montana: Ravalli Co.: Mill Cr. at Hwy. 93, 7 mi. N. Hamilton, 71-08-02, P.D.
Perkins (32/55 PDP). Oregon: Curry Co.: Euchre Cr. at Hwy. 101 by Ophir, 65-09-28, H.B. Leech (7/8 CAS). Pistol
River, 52-06-18, B. Malkin (4/3 CFMNH). Douglas Co.; S. Umpqua R. at Canyonville, 71-07-17, P.D. Perkins (4/3
PDP). Washington: King Co. Green River Gorge, 56-07-15, Malkin & Kottke (2/1 CFMNH).

6. Limnebius arenicolus new species

Map: Figure 76C
Paratypes: 472

Mexico: Baja California: Sierra San Pedro Martir, La Grulla, 6900’, 52-06-12, P.H. Arnaud, Jr. (1/1 CAS).

United States: California: Butte Co.: Little Chico Cr. at School Rd., E. of Forest Ranch, 2300’, 61-09-01, H.B.
Leech (2/0 CAS). Glenn Co.: NW corner Glenn Co., Plaskett Mdws., 6000’, stream from N. entering Lower Plaskett
Lake, 60-07-28, H.B. Leech (15/9 CAS). NW corner Glenn Co., 4.5 mi. NW of Lanes, Redwood Flat, 60-08-05, H.B.
Leech (1/0 CAS). Humboldt Co.: Korbel, 16-06-16, no collr. (2/4 CAS). Willow Creek, 16-06-12, F.E. Blaisdell (2/2
CAS). Green Point Ranch, 1500’, 16-06-05, F.E. Blaisdell (1/1 CAS). N. Fork Yager Cr. at Bridgeville-Kneeland
Road, 66-08-08, H.B. Leech (1/3 CAS). Toss-up Creek, confluence with Redwood Creek, 2.5 mi. N. of road to Hoopa,
650’, 70-08-13, H.B. Leech (1/0 CAS). Lake Co.: Creek behind Cottage City Resort, Lucerne, 53-07-05, H.B. Leech
(1/0 CAS). Bartlett Creek, Bartlett Springs, 55-08-01, H.B. Leech (1/0 CAS). Headwaters, Long Valley Cr., 3750’,
55-08-01, H.B. Leech (2/1 CAS). Little Blue Lake, 47-11-08, H.P. Chandler (1/0 CAS). Los Angeles Co.: Pasadena,
no date, H.C. Fall (2/0 CAS). Pasadena, no date, no collr. (2/2 CAS). Pasadena, no date, A. Fenyes (1/1 CAS; 1/1
CFMNH; 1/2 CU; 1/0 MCZ). Pasadena, 17-09-06, J.O. Martin (6/2 CAS). Pomona, no date, no collr. (1/1 USNM).
Big Rock Cr., San Gabriel Mts., 59-03-31, P.H. Raven (3/8 CAS). Marin Co.: Lake Lagunitas, 19-10-18, J.O. Martin
(21/20 CAS). Same, 19-01-09 (1/2 CAS). Mill Valley, Cascade Creek, 51-05-09, R.E. Leech (4/14 CAS). Same,
52-04-04 (8/8 CAS). Mill Valley, Cascade Cyn., roadside trickle, 57-03-31, H.B. Leech (1/1 CAS). Mill Valley,
57-04-25, H.B. Leech (1/0 CAS). Muir Woods, 08-08-30, no collr. (1/1 CAS). Muir Woods, 47-10-13, D. Giuliani
(1/0 CAS). Lagunitas, no date, F.E. Blaisdell, (5/2 CAS). Lagunitas Cr. at Tocaloma, 68-05-04, H.B. Leech (3/4
CAS). Redwood Cr. at Hwy. 1, 71-10-24, P.D. Perkins (5/5 PDP). No site, 19-10-18, J.O. Martin (1/1 CAS).
Mendocino Co.: Bloody Run Cr., 7 mi. E. of Route 101 on Longvale-Covelo road, 1100’, 68-07-18, H.B. Leech (5/3
CAS). Dry Cr., Hwy. 128, 64-09-05, W.B. Leech (1/0 CAS). Pardaloe Cr., 1 mi. SW Mailliard Redwoods State Park,
64-09-06, H.B. Leech (2/0 CAS). Eel River, 4.5 mi. NW of Lanes, Redwood Flat, 60-08-05, H.B. Leech (1/0 CAS).
McDowell Cr., at foot of grade below Oasis, 1000’, 55-07-27, H.B. Leech (12/2 CAS). Rancheria Cr., 5.5 mi. SE
Booneville, 50-06-15, H.B. Leech (1/0 CAS). Longvale Cr., 38-07-27, no collr. (1/1 CAS). Beebe Cr., 50-09-05, H.B.
Leech (2/3 CAS). Bear Pen Canyon Cr. just above junction with Burger Cr., Dos Rios-Laytonville Rd., 72-08-30, H.B.
Leech (1/0 CAS). Baechtel Creek, 3 mi. W. Willits, 48-06-15, H.B. Leech (4/2 CAS). Monterey Co.: Tassajara Hot
Springs, 54-05-26, Bryant, (14/8 CAS). Carmel, 31-07-18, no collr. (1/1 CAS). Nacimiento River, Ponderosa Public
Camp, 70-09-06, P.D. Perkins (20/30 PDP). Carmel, 53-06-28, B. Malkin (1/0 CFMNH). Napa Co.: Campbell Cr.,

Quaest. Ent., 1980, 16 (1,2)

502

Perkins

51- 04-10, H.B. Leech (3/0 CAS). Pope Cr. at Walter Springs Rd., 520’, 64-08-18, H.B. Leech (1/0 CAS). 6 mi. NE
Rutherford, 71-07-16, P.D. Perkins (2/1 PDP). Nevada Co.: Sagehen Cr., 6300’, 66-07-20, W.J. Turner (8/3 UBC).
Same, 67-07-18 (4/7 UBC). Plumas Co.: Chester, 14-10-15, R. Hopping (1/0 CAS). Riverside Co.: San Jacinto Mts.,
4000', no date, F.E. Winters (3/2 CAS). San Bernardino Co.: Hesperia, 18-06-30, no collr. (2/1 CAS). San Diego Co.:
Camp Pendleton, Oceanside, 45-10-15, H.P. Chandler (1/0 CAS). San Mateo Co.: La Honda, 25-07-29, F.E. Blaisdell
(2/0 CAS). No site, no date, no collr. (4/4 CAS). Santa Barbara Co.: Santa Barbara, no date, F.E. Winters (1 /0 CAS;
1/2 CU). Santa Inez Mts., no date, F.E. Winners (1/1 CAS). Santa Barbara Mts., no date, H.C. Fall (1/0 MCZ).
Santa Clara Co.: Los Gatos, 04-06-10, no collr. (1/0 CAS). Santa Cruz Co.: Ben Lomond, 60-10-10, D. Miller (1/0
CAS). Shasta Co.: Bailey Cr., 2.5 mi. W. & S. of Viola, 61-08-31, H.B. Leech (4/0 CAS). Cottonwood Cr., N.F.,

52- 10-24, H. P. Chandler (1/0 CAS). Sonoma Co.: Austin Cr., 2 mi. S. Cazadero, 54-10-30, H.B. Leech (1/0 CAS).
Mark West Cr. at Calistoga Rd., ca 4 mi. S. of Petrified Forest, 63-07-08, H.B. Leech (1/1 CAS). Guerneville,
08-07-23, F.E. Blaisdell (4/2 CAS). Duncan Mills, 08-06-28, F.E. Blaisdell (1/3 CAS). Sonoma Creek, Glen Ellen,
50-04-29, H.B. Leech (1/0 CAS). Calistoga, 34-06-12, Bryant (2/4 CAS). Camp Meeker, no date, Wintersteiner (3/2
CAS). Camp Meeker, 51-07-10, P.S. Bartholomew (1/2 CAS). Duncan Mills, 08-07-04, no collr. (4/1 USNM). No
site, no date, no collr. (2/0 CAS). No site, no date, Hubbard & Schwarz (3/6 USNM). Trinity Co.: SW corner Trinity
Co., Wilson Cr., Lake Mtn. area, 60-07-30, H.B. Leech (3/11 CAS). Big Slide Cr., 5 mi. NW of Hyampon, 68-07-24,
H.B. Leech (2/0 CAS). Little Brown Cr. at Route 3, ca 3 mi. airline SW Douglas City, 70-08-11, H.B. Leech (2/1
CAS). Bridge Gulch Cr. at Natural Bridge, 7.5 mi. airline N. Wildwood, 70-08-10, H.B. Leech, (1/0 CAS). Mad River
just above mouth Van Horn Cr., 4.25 air miles SE of Ruth, pools in drying bed of upper Mad River, 70-08-07, H.B.
Leech (1/1 CAS). Hayfork Creek at Hayfork-Wildwood Rd., 70-08-11, H.B. Leech (1/1 CAS). Van Horn Creek, 1.5
mi. above its mouth at upper Mad River, 2850’, 70-08-09, H.B. Leech (5/3 CAS). Tuolumne Co.: Jackass Cr., 4.2 mi.
SE of Priest, on Coulterville Rd., 2100’, 62-08-19, H.B. Leech (5/3 CAS). Niagara Cr., Forest Campgd., 6600’,
62-08-09, H.B. Leech (1/1 CAS). Oregon: Curry Co.: Myers Cr., Pistol River, 38-05-18, H.B. Leech (2/1 CAS).
Klamath Co.: 11 mi. NE Bly, edge Deming Cr., 66-05-13, J. Schuh (1/0 JS). Lake Co.: Warner Cr., Warner Cyn., N.
of Lakeview, 56-07-01, H. B. Leech (1/0 CAS). Lakeview, 52-06-22, B. Malkin (2/1 CFMNH). Washington Co.:
Banks, 58-08-09, P.S. Bartholomew (4/5 CAS).

7. Limnebius leechi new species

Map: Figure 76B
Paratypes: 54

United States: California: Lake Co.: Creek behind Cottage City Resort, Lucerne, 53-07-05, H.B. Leech (3/1 CAS).
Kelseyville, Kelsey Creek, 49-05-29, H.B. Leech (4/0 CAS). Headwaters, Long Valley Cr., 3750’, 55-08-01, H.B. Leech
(2/4 CAS). Los Angeles Co.: Mt. near Claremont, no date, Baker (1/1 CMP). Madera Co.: Windy Gap, 2000’,
46-07-13, H.P. Chandler (1/2 CAS). Mendocino Co.: McDowell Cr., just below Oasis, 1800’, 55-07-27, H.B. Leech
(4/4 CAS). Monterey Co.: The Indians, 2 mi. SE of Santa Lucia Memorial Park, seepage trickle over gravelly soil,
56-01-15, H.B. Leech (1/0 CAS). Napa Co.: 6 mi. NE Rutherford, 71-07-16, P.D. Perkins (2/6 PDP). San Bernardino
Co.: Lake Arrowhead, 44-07-27, G.P. Mackenzie (1/2 CAS). Hesperia, 18-06-30, no collr. (1/0 CAS). Lake
Arrowhead, 53-07,26, G.H. Nelson (2/0 MCZ). San Diego Co.: San Vicente, 59-02-25, I. Moore (1/0 CAS). Camp
Pendleton, Oceanside, 45-10-26, H.P. Chandler (1/0 CAS). Santa Clara Co.: San Antonio Vail., 48-03-11, J.W.
MacSwain, (1/0 UCB). Trinity Co.: SW corner Trinity Co., Wilson Cr., Lake Mtn. area, 60-07-30, H.B. Leech (2/0
CAS). Mad River just above mouth Van Horn Creek, 4.25 air miles SE of Ruth, pools in drying bed of Upper Mad
River, 70-08-07, H.B. Leech (4/2 CAS).

8. Limnebius borealis new species

Map: Figure 76B
Paratypes: 37

Canada: British Columbia: Enderby, Shuswap River, 46-10-1 1, H.B. Leech (7/5 CAS).

United States: Montana: Blaine Co.: Bear Paw Mt., no date, Hubbard & Schwarz (8/8 USNM). Ravalli Co.: Mill
Cr. at Hwy. 93, 7 mi. N. Hamilton, 71-08-02, P.D. Perkins (9/0 PDP).

10. Limnebius sinuatus (Sharp)

Map: Figure 74
Specimens examined: 623

Guatemala: Baja Verapaz: 34 mi. S. Rabinal, stream in semi-arid hills, 74-06-12, ME & PD Perkins (3/4 PDP). 1
mi. S. San Jeronimo, rapid stream in pines, 74-06-03, ME & PD Perkins (2/1 PDP). Huehuetenango: 35 mi. S. La

Western Hemisphere Hydraenidae

503

Mesilla, tropical brook, 74-05-31, ME & PD Perkins (5/9 PDP). 6 mi. NW Huehuetenango, stream in oak-pine,
74-06-29, ME & PD Perkins (45/60 PDP). 42 mi. S. La Mesilla, outwash area of river, 74-05-31, ME & PD Perkins
(25/29 PDP). 2 mi. NW Huehuetenango, stream in oak-pine, 74-06-29, ME & PD Perkins (13/16 PDP). Jalapa: 6 mi.
N. Jalapa, slow stream in open, xeric situation, 74-06-15, ME & PD Perkins (28/45 PDP). Totonicapan: 25 mi. S.
Huehuetenango, small rapid stream, 74-06-01, ME & PD Perkins (1/0 PDP).

Mexico: Chiapas: 4 mi. N. Bochil, stream in pine forest, 74-05-28, ME & PD Perkins (7/6 PDP). Durango: 15 mi.
W. Durango, river outwash area, 74-07-17, ME & PD Perkins (11/14 PDP). Jalisco: 20 mi. NE La Huerta, rapid
tropical stream, 74-07-22, ME & PD Perkins (3/4 PDP). Oaxaca: 14 mi. N. Huajuapam de Leon, 74-07-09, P.D.
Perkins (5/8 PDP). 21 mi. SE Huajuapam de Leon, brook in scrub-thorn desert, 74-07-09, ME & PD Perkins (14/10
PDP). 7 mi. NE Oaxaca, 74-07-08, ME & PD Perkins (1/1 PDP). San Luis Potosi: 2 mi. S. San Luis Potosi, 48-11-21,
H.B. Leech (3/0 CAS). 6 mi. W. San Luis Potosi, stream outwash in desert 74-07-26, P.D. Perkins (4/0 PDP).
Zacatecas: 13 mi. S. Jalpa, stream in desert, 74-07-16, ME & PD Perkins (1/2 PDP). 29 mi. SW Zacatecas, stream in
desert, 74-07-16, ME & PD Perkins (2/4 PDP).

United States: Arizona: Cochise Co.: Sunnyside Cyn., W. side Huachuca Mts., 6000’, 52-08-04, H.B. Leech, (3/1
CAS). Chiricahua Mts., 3/5 mi. SW Portal, 5000', 52-08-13, H.B. Leech (2/9 CAS). Huachuca Mts., Garden Canyon,
50-06-02, C.P. Alexander (0/1 MCZ). Portal, SWRS, 76-05-14, W.E. Steiner (4/7 USNM). Chiric, Mts., no date,
Hubbard & Schwarz (5/4 USNM). SW Res. Sta., 63-07-11, P.J. Spangler (38/47 USNM). Chiricahua Mts., above
Herb Martyr, 74-06-22, H.P. Brown (9/2 HPB). Coconino Co.: Midgley Bridge, Oak Cr. Canyon, 52-08-25, H.B.
Leech (11/16 CAS). Gila Co.: Globe, 48-10-13, F.H. Parker (2/10 CAS). Pinal Creek, Globe, 4000’, 53-04-24, A. &
H. Dietrich (1/0 CU). Pima Co.: Santa Catalina Mts., 34-02-04, Bryant (1/0 CAS). Santa Cruz Co.: Yank’s Spring,
Sycamore Cyn., Tumacacori Mts., 52-08-03, H.B. Leech (3/7 CAS). Colorado: Routt Co.: Steamboat Springs,
41-10-01, O. Bryant (1/0 CAS). Texas: Jeff Davis Co.: Limpia Creek, 74-06-26, H.P. Brown (5/5 PDP). Limpia Creek
Canyon, Davis Mts., 52-09-05, B. Malkin (20/24 CFMNH).

16. Limnebius octolaevis new species

Map: Figure 74
Paratypes: 31

Guatemala: Baja Verapaz: 4 mi. S. Rabinal, stream, transition xeric-tropical, 74-06-10, ME & PD Perkins (2/0
PDP). 10 m. S. Rabinal, 74-06-12, ME & PD Perkins (3/0 PDP). Totonicapan: Same data as holotype (14/12 PDP).

4. Gymnochthebius germaini (Zaitzev)

Map: Figure 87A
Specimens examined: 60

Argentina: Chubut: Hoyo de Epuyen, 74-02-10, O.S. Flint (1 USNM). Neuquen: 9 km SE San Martin de los
Andes, 74-01-24, O.S. Flint (2 USNM).

Chile: Cautin: 8 km E. Temuco, 51-01-08, Ross & Michelbacher (1 CAS). Lanco, 69-06-03, P. & P. Spangler (22
USNM). Concepcion: Cabrero, 69-06-02, P. & P. Spangler (1 USNM). Maule: Rio Nirivilo, 71-11-02, H.P. Brown (1
USNM). Orsorno: 8 km S. Orsorno, 69-06-04, P. & P. Spangler (13 USNM). Valdivia: 8 mi. E. Rio Bueno, 51-01-15,
Ross & Michelbacher (2 CAS). San Jose Mariquina, 69-06-07, P. & P. Spangler (13 USNM). 4 km. N. San Jose
Mariquina, 69-06-03, P. & P. Spangler (1 USNM). Valparaiso: Colliquay, 63-1 1-05, L. Pena (1 MCZ).

5. Gymnochthebius chilenus (J. Balfour-Browne)

Map: Figure 87A
Specimens examined: 13

Chile: Maule: Rio Nirivilo, 71-11-02, H.P. Brown (10 USNM). Rio Maule, 71-11-02, H.P. Brown (2 USNM).
Concepcion: Cabrero, 69-06-02, P. & P. Spangler (1 USNM).

6. Gymnochthebius clandestinus new species

Map: Figure 87B
Paratypes: 190

Chile: Cautin: Lanco, 69-06-03, P. & P. Spangler (7 USNM). Pitrufquen, 69-06-03, P. & P. Spangler (3 USNM).
Concepcion: Escuadron, 69-05-30, Spangler & Cekalovic (66 USNM). Malleco: 11 km N. Victoria, Rio Dumo,
potholes, 78-01-25, P.J. Spangler (20 USNM; 20 MHNC). Maule: Rio Nirivilo, 71-09-02, H.P. Brown (26 USNM).

Quaest. Ent., 1980, 16 (1,2)

504

Perkins

Orsorno: 8 km S. Orsorno, 69-06-04, P. & P. Spangler (22 USNM). Valdivia: 8 mi. E. Rio Bueno, pond in field,
51-01-15, Ross & Michelbacher (8 CAS). Pichi Ropulli, 69-06-04, P. & P. Spangler (2 USNM). 4 km N. San Jose
Mariquina, 69-06-03, P. & P. Spangler (14 USNM). San Jose Mariquina, 69-06-07, P. & P. Spangler (2 USNM).

7. Gymnochthebius tectus new species

Map: Figure 87B
Paratypes: 1 1

Chile: Maule: Rio Nirivilo, 71-11-02, H.P. Brown (1 USNM). Santiago: Farellones, 62-04-08, L. Pena (10 MCZ).
1 1. Gymnochthebius topali (J. Balfour-Browne)

Map: Figure 90B
Specimens examined: 18

Argentina: Rio Negro, El Bolson, 61-10-13, Topal (10 HNHM)

Chile: Bio-Bio: Negrete, 51-01-29, Ross & Michelbacher (4 CAS). Cautin: 20 km E. Temuco, 51-01-07, Ross &
Michelbacher (4 CAS).

17. Gymnochthebius nitidus (LeConte)

Map: Figure 90A
Specimens examined: 61

Canada: Ontario: Essex Co.: Wheatley, 67-05-01, K. Stephan (6 KS). Kent Co.: Tilbury, 67-06-01, K. Stephan (7
KS). Northwest Territories: Rabbitskin R., 23 mi. SE Ft. Simpson, 72-06-12, A. Smetana (1 CNC). Quebec:
Kazubazua, 31-08-18, W.J. Brown (1 CNC). Wakefield, 30-06-04, W.J. Brown (6 CNC). Pettit, no date, Hubbard &
Schwarz (1 CNC: 3 USNM). ^

United States: Fairfield Co.: Cornwall, 20-05-16, Chamberlain (1 MCZ). St. Vincent, no date, no collr. (4 CAS).
Illinois: Champaign Co.: Mahomet, Nettie Hart Woodland Memorial, black lite trap, 66-09-03, M.W. Sanderson (1
PDP). Cook Co.: Riverside, 09-04-25, F. Psota (3 CFMNH). Iowa: Johnson Co.: Iowa City, 96-05-03, no collr. (1
USNM). Michigan: Eaton Co.: Grant Ledge, no date, Hubbard & Schwarz (1 USNM). Oakland Co.: No site,
21-07-03, M.H. Hatch (6 UWA). Washtenaw Co.: No site, 21-07-05, M.H. Hatch (1 UWA). Missouri: Boone Co.:
Silver Fork St. St. 5, 76-08-18, R.W. Shepard (1 USNM). Jackson Co.: Englewood, Cedar Creek, 54-10-09, P.J.
Spangler (1 USNM). Montana: Blaine Co.: Bear Paw Mt., no date, Hubbard & Schwarz (9 USNM). New Jersey:
Passaic Co.: Totowa, no date, Wintersteiner (1 CAS). New York: Tompkins Co.: Ithaca, 19-09-05, E.A. Richmond (1
CAS). Pennsylvania: No site, no date, no collr. (1 CNC; 2 ASP; 1 USNM; 1 CAS).

18. Gymnochthebius fossatus (LeConte)

Map; Figure 92B
Specimens examined: 722

Argentina: Tucuman: 20 km S. Tucuman, 69-05-23, P. & P. Spangler (18 USNM).

Bolivia: Santa Cruz: Santa Cruz, 69-05-12, P. & P. Spangler (1 USNM). Okinawa, 58-06-06, E. Pinckert (1 CAS).
Brazil: Ceara: Riacho Cobra pres Arara, 37-09-23, O. Shubart (2 ISNB). Goias: Santa Isable, Ilha do Bananal, Rio
Araguaia, 57-08-20, B. Malkin (73 CAS). Pernambuco: Belem, Rio Sao Francisco, shoreline of shallow water on a small
island, adhering to stones, 37-09-03, O. Shubart (1 ISNB). Bom Jardim, Lagoa de Palma, 37-11-10, O. Shubart (2
ISNB). Rio Grande do Norte: Ceara-Mirim, 69-07-07, P. & P. Spangler (1 USNM).

Colombia: Atlantico: Barranquilla, 69-03-18, P. & P. Spangler (1 USNM). Magdalena: 8 km E. Baranquilla,
69-03-19, P. & P. Spangler (2 USNM).

Cuba: Soledad, (Cienfuegos), 36-04-15, Darlington (28 MCZ). Cauto El Cristo, Cauto R., 36-08-12, Darlington (2
MCZ). No site, no date, no collr. (3 ASP).

Guatemala: Escuintala: 17 mi. E. Escuintla, 65-07-08, P.J. Spangler (5 USNM).

Honduras: Comayagua: Stream near south end Lago de Yojoa, 74-06-19, M.E. & P.D. Perkins (2 PDP). Cortes: 24 mi.
S. San Pedro Sula, clear, slow stream, 74-06-19, M.E. & P.D. Perkins (6 PDP). Choluteca: San Marcos Coin, 65-07-28,
P.J. Spangler (5 USNM).

Jamaica: Kingston, 34-08-29, Darlington (1 MCZ). St. Catherine, Bushy Park, ex. small pool in narrow gully,
47-02-09, G.B. Thompson (5 IOJ).

Mexico: Aguascalientes: Aguascalientes, 63-08-05, P.J. Spangler (56 USNM). Baja California: Arroyo de la

Western Hemisphere Hydraenidae

505

Purisima, 1 mi. upstream from town, 58-12-27, H.B. Leech (13 CAS). Chiapas: 8 mi. W. Teapa, large tropical stream,
74-05-26, ME & PD Perkins (5 PDP). Distrito Federal: Mexico City, 50-07-30, Drake & Hottes (1 USNM). Durango:
Durango, no date, Wickham (1 MCZ). 15 mi. W. Durango, river outwash area, 74-07-17, ME & PD Perkins (2 PDP).
Morcillo, Lake Pena del Aquila, 64-06-28, P.J. Spangler (9 USNM). Hidalgo: Pachuca, 64-08-21, P.J. Spangler (25
USNM). Jalisco: 15 mi. NE Atenquique, 48-12-05, H.B. Leech (13 CAS). 15 mi. N. Chapala, 63-08-02, P.J. Spangler
(4 USNM). MExico: Chapingo, en arena del rio, 59-02-01, 1. Martell (19 USNM). 11 mi. E. Texcoco, desert stream,
74-05-23, ME & PD Perkins (2 PDP). Michoacan: Patzcuaro, 64-07-07, P.J. Spangler (1 USNM). Morelia, 64-07-08,
P.J. Spangler (1 USNM). Puebla: Acatlan, 65-08-25, P.J. Spangler (1 USNM). San Luis Potosi: 2 mi. S. San Luis
Potosi, 48-11-21, H.B. Leech (1 CAS). Tamaulipas: Nr. San Antonio, 69-07-27, F.N. Young (29 FNY). Zacatecas: no
date, Wickham (2 MCZ). 13 mi. S. Jalpa, stream in desert, 74-07-16, ME & PD Perkins (2 PDP). 29 mi. SW
Zacatecas, stream in desert, 74-07-16, ME & PD Perkins (1 PDP).

Puerto Rico: L. Guanica, 38-05-31, Darlington (7 MCZ). Nr. Fajardo, rt. 194 km 46.7, 61-08-20, Flint & Spangler
(120 USNM).

United States: Arizona: Cochise Co.: Bisbee, Wood Cn., U.V. It., 61-07-03, P. Johnson (1 UA). Coconino Co.:
Flagstaff, 53-07-01, B. Malkin & J. Farmer (3 CFMNH). Navajo Co.: Winslow, no date, Wickham (1 MCZ). Pima
Co.: Colossal Cave Park, 68-02-18, K. Stephan (1 KS). Arivaca, 70-04-11, K. Stephan (1 KS). Tanque Verde, drift,
58-11-23, Werner-Adachi (1 UA). Arivaca Creek at Arivaca, 52-07-31, H.B. Leech (55 CAS). Tucson, no date,
Hubbard & Schwarz (2 USNM). Santa Cruz Co.: Pajarito Mts., Sycamore Cyn., 68-08-24, K. Stephan (1 KS). Yuma
Co.: Alamo Crossing, u.v. It., 62-07-14, Werner & Johnson (1 UA). Ft. Yuma, no date, Hubbard & Schwarz (1
USNM). Florida: Brevard Co.: Titusville, 11-11-08, no collr. (1 CAS). Hillsborough Co.: Tampa, no date, F.C.
Bowditch (3 MCZ). Orange Co.: No site, no date, no collr. (2 ASP). Volusia Co.: Enterprise, no date, no collr. (3 ASP).
Enterprise, no date, F.C. Bowditch (2 MCZ). Enterprise, no date, Hubbard & Schwarz (4 USNM). Lake Harney, no
date, Hubbard & Schwarz (2 USNM). New Mexico: Bernalillo Co.: Albuquerque, no date, Hubbard & Schwarz (3
USNM). No site, no date, no collr. (2 OSU; 2 ASP; 2 MCZ; 3 USNM). Oklahoma: Marshall Co.: UOBS, Lake
Texoma, Willis, at light, 68-07-09, W. Suter (1 USNM). Texas: Bear Co.: San Antonio, no date, Wickham (1 ASP).
Cameron Co.: Esperza Rch., Brownsville, no date, no collr. (2 CU; 2 USNM). Brownsville, no date, Wickham (1 ASP;
4 USNM; 13 MCZ). Brownsville, 33-06-16, Darlington (28 MCZ). Brownsville, in banana debris, 37-03-1 1, no collr. (1
USNM). Colorado Co.: Columbus , no date, Wickham (1 USNM). Jeff Davis Co.: Davis Mts., 71-02-01, K. Stephan (3
KS). Davis Mts., Limpia Creek Canyon, 52-09-05, B. Malkin (1 CDMNH). Val Verde Co.: Del Rio, no date, no collr.
(1 CAS).

19. Gymnochthebius falli new species

Map: Figure 94B
Paratypes: 39

United States: Arizona: Maricopa Co.: Salt Creek, no date, Wickham (2 USNM). Idaho: Twin Falls Co.: Magic
Hot Springs, 57-07-20, B. Malkin (1 UWA). Kansas: Logan Co.: Same data as Holotype (2 CAS; 2 MCZ; 2 CNC; 29
USNM). Texas: Jeff Davis Co.: Limpia Creek, 74-06-26, H.P. Brown (1 PDP).

20. Gymnochthebius laevipennis (LeConte)

Map: Figure 94B
Specimens examined: 23

Mexico: Baja California: Arroyo de la Purisima, 1 mi. upstream from town, 58-12-27, H.B. Leech (4 CAS). Norte,
Estero at mouth Arroyo del Rosario, no date, H.B. Leech & P.H. Arnaud (1 CAS).

United States: California: Riverside Co.: Riverside, no date, F.E. Winters (2 CU: 5 CAS). San Jacinto, no date,
F.E. Winters (2 MCZ). San Jacinto Mts., no date F.E. Winters (5 USNM). San Diego Co.: Oceanside, Camp
Pendleton, 45-10-18, H.P. Chandler (1 CAS). Santa Barbara Co.: Santa Barbara, no date, F.E. Winters (1 CAS).
Unspecified Co.: No site, no date, no collr. (1 ASP). Oregon: Douglas Co.: Glendale, 38-07-14, M.H. Hatch (1 UWA).

1. Ochthebius pacificus new species

Map: Figure 101A
Paratypes: 230

United States: California: Glenn Co.: 0.5 mi. W. Newville, N. fork Stony Cr., 66-04-04, H.B. Leech (1 CAS). Trib.
to Stony Cr., 7 mi. N. Stonyford, 56-03-29, H.B. Leech (5 CAS). Humboldt Co.: Bear River at Capetown, 65-10-01,
H.B. Leech (4 CAS). South Eel River at Weott, 155’, 70-08-30, H.B. Leech (37 CAS). Willow Cr. just about its E.
fork, 1500’, 70-08-29, H.B. Leech (8 CAS). North Dobbyn Cr., Alderpoint, Blocksburg Rd., 450’, 68-07-19, H.B Leech

Quaest. Ent., 1980, 16 (1,2)

506

Perkins

(4 CAS). Mendocino Co.: 5.5 mi. SE Boonville, Rancheria Cr., 50-06-15, H.B. Leech (2 CAS). 8 mi. W. Navarro,
Navarro River, 50-06-15, H.B. Leech (7 CAS). Cummisky Cr. at Mt. House-Hopland Rd., 64-10-10, H.B. Leech (14
CAS). Dry Cr., Hwy. 128, 64-09-05, H.B. Leech (9 CAS). 2 mi. S. Yorkville, tiny stream, 54-07-25, H.B. Leech (1
CAS). 2 mi. NW Philo, Hendy Woods State Park, 64-07-22, P. Rubtzoff (1 CAS). Garcia River at Hwy. 1, 64-10-12,
H.B. Leech (9 CAS). 4.5 mi. NW of Lanes, 60-08-05, H.B. Leech (5 CAS). Pieta Cr. at Route 101, Pieta, 465’,
70-08-81, H.B. Leech (1 CAS). No site, no date, Van Dyke (1 CAS). Monterey Co.: Carmel River, 50-08-20, P.S.
Bartholomew (6 CAS). Little Sur River, vie. P. Ocean, 70-09-06, P.D. Perkins (25 PDP). Carmel, 56-09-21, B. Malkin
(61 CFMNH). Carmel, 53-06-28, B. Malkin (1 CFMNH). Napa Co.: Wheatfield Br. of Burton Cr., Pope Valley,
64-05-10, H.B. Leech (2 CAS). Pope Cr. at Walter Springs Rd., 520’, 64-08-24, H.B. Leech (1 CAS). Santa Barbara
Co.: Santa Barbara, no date, F.E. Winters (2 CAS). Siskiyou Co.: Stream flowing into Meeks Meadow Lake, 6.25 mi.
airline SW Etna, 72-08-23, H.B. Leech (1 CAS). Sonoma Co.: Sonoma, 50-04-29, H.B. Leech (7 CAS). Gualala River
at bridge, Annapolis & Stewarts Point-Healdsburg Rd., 64-09-07, H.B. Leech (3 CAS). Duncan Mills, 08-07-09, F.E.
Blaisdell (2 CAS). Cloverdale, 26-09-19, V.S. Brown (7 CAS). The Geysers, 70-09-07, P.D. Perkins (5 PDP). Trinity
Co.: Hayfork Cr. at bridge near Carrier Gulch, Wildwood R., R., 72-08-07, H.B. Leech (3 CAS). Trinity River at Big
Flat, 60-08-04, H.B. Leech (3 CAS). Nevada: Clark Co.: 15 mi. S. Overton, spring, 66-03-31, J. Schuh (1 JS). Oregon:
Douglas Co.: Glendale, 38-06-14, M.H. Hatch (2 UWA). Lincoln Co.: Newport, seepage area, 63-05-04, T. Schuh (2
JS). Washington: King Co.: Cedar Mt., 40-05-09, M.H. Hatch (1 UWA).

2. Ochthebius arenicolus new species

Map: Figure 101 B

Paratypes: 320

Mexico: Baja California: La Suerte, Sierra San Pedro Martir, pool in canyon, 3700’, 63-06-04, R.K. Benjamin (121
CAS). 17 mi. W. Bahia de Los Angeles, 62-05-29, R. & E. Ryckman and C. Christianson (8 CAS).

United States: California: Colusa Co.: Trib. of E. branch Little Indian Cr., 6.2 mi. S. Lodoga, 66-04-04, H.B. Leech
(29 CAS). Indian Cr., 1.5 mi. along road to Cooks Springs, SW of Lodoga, 71-10-10 H.B. Leech (29 CAS). Indian Cr.,
Cooks Springs, 4 air mi. SW Lodoga, 1480’, 71-07-03, H.B. Leech, (25 CAS). Trib. to Bear Cr., Robbers Flat below
Brim Grade, 419 m., 71-10-10, H.B. Leech (1 CAS). Wilbur Springs, 1250’, 71-07-17, P.D. Perkins (6 PDP). Contra
Costa Co.: Berkeley, 42-06-07, W. Cook (1 CAS). Marsh Creek, 37-04-10, H.B. Leech (1 CAS). Del Norte Co.: No
site, 10-06-01, Nunenmacher (1 CFMNH). Humboldt Co.: Bear R. at Capetown, 65-10-01, H.B. Leech (1 CAS). Burr
Cr., 3 mi. S. of Bridgeville, 1200’, 68-07-19, H.B. Leech (1 CAS). Mill Cr., 7.5 mi. S. of Bridgeville, 1200’, 68-07-19,
H.B. Leech (2 CAS). N. Fork Yager Cr. at Bridgeville-Kneeland Rd., 1300’, 66-08-08, H.B. Leech (1 CAS). Lake Co.:
Bear Cr. at Crabtree Hot Springs Rd., 55-08-04, H.B. Leech (1 CAS). Creek behind Cottage City resort, Lucerne,
53-07-05, H.B. Leech (4 CAS). 6.9 mi. N. Middletown, on h’way 29, 55-02-20, H.B. Leech (1 CAS). Marin Co.:
Redwood Cr., 1.8 mi. S. Muir Woods Nat’l. Mon., 64-10-03, H.B. Leech (1 CAS). Mendocino Co.: McDowell Cr., just
below Oasis, 1800’, 55-07-27, H.B. Leech (2 CAS). Beebe Cr., 55-09-05, H.B. Leech, (6 CAS). Parson Cr., 4.5 mi. NE
of Hopland, 64-06-30, H.B. Leech (1 CAS). Black Butte River, just above mouth, 68-07-17, H.B. Leech (1 CAS). Bear
Pen Cyn, Cr., just above junction with Burger Creek Dos Rios-Laytonville Rd., 72-08-30, H.B. Leech (1 CAS).
Monterey Co.: Lewis Cr., 52-08-29, H.B. Leech (6 CAS). Nacimiento R., Ponderosa Public Camp, 70-09-06, P.D.
Perkins (3 PDP). Riverside Co.: Salton, no date, Hubbard and Schwarz (8 USNM). San Benito Co.: Griswold Cr.,
Lyons Canyon on road to Idria, 63-07-21, H.B. Leech (7 CAS). San Luis Obispo Co.: Lopez Canyon Dam outlet,
71-09-05, P.D. Perkins (2 PDP). Santa Barbara Co.: Santa Barbara, no date, F.E. Winters (1 CAS). 1 mi. S. San
Marcos Pass, 2000’, 70-06-27, P.D. Perkins (1 PDP). Santa Ynez R., Juncal Public Camp, 70-04-27, P.D. Perkins (1
PDP). Brookshire Spr., 7 mi. E. Pine Cyn. Ranger Sta., 1500’, 72-06-18, P.D. Perkins (1 PDP). Stanislaus Co.: Del
Puerto Cr., 4 mi. by road W. of Freeway Route No. 5, 71-09-03, H.B. Leech (17 CAS). Trinity Co.: S. Fork Trinity R.,
Salmon Rock Camp, Hyampon-Big Slide Rd., 68-07-23, H.B. Leech (1 CAS). Ventura Co.: Sespe Cr., Sespe Gorge,
3500’, 72-06-18, P.D. Perkins, (1 PDP). Ojai Valley, no date, Hubbard and Schwarz (1 USNM). Ventura, no date. Fall
(2 MCZ). Unspecified Co.: No site, no date, no collr. (1 ASP). Oregon: Curry Co.: Pistol R., 56-09-17, B. Malkin (8
CFMNH).

3. Ochthebius lecontei new species

Map: Figure 99A
Paratypes: 44

Canada: British Columbia: Vernon, 29-07-06, H.B. Leech (1 CAS). Vernon, 37-09-11, H.B. Leech (1 CAS).
Vernon, Ski-jump pond, 41-04-19, H.B. Leech (1 CAS). Vernon, Pond 3, 41-04-20, H.B. Leech (14 CAS; 2 CNC).
Kamloops, 39-08-20, G.J. Spancer (8 CAS). Cranbrook, 56-08-12, G. Stace Smith (2 UBC).

United States: Montana: Madison Co.: Ziegler Hot Spgs., 52-07-27, B. Malkin (6 CFMNH). Nevada: Elko Co.:
Thousand Springs Cr., Route 30, 9 mi. NE Montello, 69-08-26, H.B. Leech (1 CAS). Wells, no date, C.T. Brues (6

Western Hemisphere Hydraenidae

507

MCZ). No site, no date. Van Dyke (1 CAS). Utah: Beaver Co.: Milford, no date, Wickham (1 MCZ).

4. Ochthebius interrupt us LeConte

Map: Figure 1 0 1 C
Specimens examined: 692

Canada: British Columbia: Vancouver, no date, no collr. (7 ASP).

Mexico: Baja California: La Salina, 4 mi. S. La Mision de San Miguel, 61-05-21, I. Moore (19 CAS). Norte, 8 mi.
upstream from Hamilton Ranch, dam site, 63-04-23, H.B. Leech (1 CAS). Norte, Estero at mouth Arroyo del Rosario,
no date, H.B. Leech and P.H. Arnaud, Jr. (1 CAS). Norte, 3.2 mi. S. Colonia Guerrero, 63-04-24, H.B. Leech (17
CAS). Norte, Mision de San Miguel, on mud, salt flat, 59-06-27, 1. Moore (41 CAS). Norte, La Salina, 71-08-20, I.
Moore (1 USNM). Norte, La Mision de San Miguel, salt marsh, 71-10-05, 1. Moore (33 UCR). Norte, La Salina, salt
marsh, 71-10-09, I. Moore (243 UCR). Mision de San Miguel, 61-05-21, I. Moore (1 CNC).

United States: California: Alameda Co.: Alameda, 22-03-07, no collr. (6 CAS). Bay Farm Island, 22-03-07, no
collr. (1 UI). Arroyo d. Valle, 72-03-06, W.H. Tyson (8 RG). 2 mi. NE Livermore, 60-07-09, no collr. (1 UCB). 10 mi.

E. Livermore, 59-03-14, D. Burdick (1 UCB). No site, 06-06-01, F. Nunenmacher (5 CFMNH). Colusa Co.: Indian
Cr., 1.5 mi. along road to Cooks Springs SW of Lodoga, 71-10-10, H.B. Leech (2 CAS).V Contra Costa Co.: Vine Hill,
13-06-07, F.E. Blaisdell (3 CAS). Albany, tide pool, 21-04-23, C.J. Dodds (8 CAS). Albany, 21-03-16, no collr. (3
CAS). Danville, 51-06-01, F.X. Williams (3 CAS). Martinez, no date, Wickham (4 USNM). Albany, tide pool,
21-02-26, no collr. (2 UI). Glenn Co.: N. Fork Stony Creek, 0.5 mi. W. of Newville, 66-04-04, H.B. Leech (9 CAS).
Trib. to Stony Cr., 7 mi. N. Stonyford, 53-03-29, H.B. Leech (23 CAS). Kings Co.: Stratford, 50-08-21, P.S.
Bartholomew (1 CAS). Lake Co.: Clear Lake State Park, wet edge of Clear Lake, 64-1 1-10, P. Rubtzoff (1 CAS). Los
Angeles Co.: Redondo, 44-06-07, G.P. Mackenzie (6 CAS; 1 CU). Redondo, 44-05-24, G.P. Mackenzie (4 CNC; 4
UA). Redondo, no date, no collr. (4 SDSU; 2 CFMNH). Redondo, no date, A. Fenyes (4 CU; 1 USNM). Redondo, no
date, H.C. Fall (2 CAS). Los Angeles, no date, no collr. (3 CAS). L. Redondo, no date, F. Winters (8 CAS). Tejon
Pass, 18-07-28, J.O. Martin (5 CAS). Pomona, no date, no collr. (6 CNC). Marin Co.: Smiths Lake, Manor, 55-11-21,
H.B. Leech (3 CAS). Headwaters of Salmon Cr., Wilson Hill road, 64-02-22, H.B. Leech (1 CAS). Dipsea, no date,

F. E. Blaisdell (1 CAS). Mendocino Co.: N. Branch Mill Cr., Covelo-Paskenta road near Covelo, 68-07-17, H.B. Leech
(8 CAS). Napa Co.: Burton Cr., Pope Valley, 64-05-10, H.B. Leech (1 CAS). Pope Creek at Walter Springs road, 520’,
64-08-24, H.B. Leech (1 CAS). Orange Co.: San Juan, 17-08-13, no collr. (1 CAS). Laguna Beach, no date, no collr. (2
CAS). Riverside Co.: Sonorian Region, no date, F.E. Winters (4 CAS). Riverside, no date, F.E. Winters (4 CAS).
Elsinore Lake, 17-09-01, J.O. Martin (3 CAS). San Jacinto Mts., no date, F.E. Winters (2 CAS). San. Benito Co.: Farm
pond, Mendota-Hollister road at Panoche Pass, 63-07-21, H.B. Leech (32 CAS). San Diego Co.: Oceanside, 45-10-23,
H.P. Chandler (1 CAS). 1 mi. S. Carlsbad, 68-08-28, P.S. Bartholomew (1 CAS). San Diego, 17-08-17, J. O. Martin (3
CAS). Mission Valley, 35-08-19, 1. Moore (2 CAS). Torrey Pines, edge of Soledad Canyon, Lagun, 50-08-06, I. Moore
(1 CAS). Camp Pendleton, Oceanside, 45-10-26, H.P. Chandler (1 CAS). San Luis Obispo Co.: Lopez Canyon Dam
outlet, 70-09-05, P.D. Perkins (4 PDP). Santa Barbara Co.: Santa Inez Mts., Santa Barbara, no date, F.E. Winters (3
CAS). Santa Barbara, no date, F.E. Winters (12 CAS; 1 USNM; 3 CU). Montecito, no date, F.E. Winters (5 CAS).
Santa Cruz Island, no date, F.E. Winters (1 CAS). Santa Cruz Co.: Seabright, 24-07-18, F.E. Blaisdell (4 CAS; 8
ASP). Santa Cruz, 37-11-15, J.W. Tilden (4 CAS). Sonoma Co.: Guerneville, 08-07-23, F.E. Blaisdell (2 CAS). Yolo
Co.: Woodland, 33-05-22, E.C. Zimmerman (1 USNM). Unspecified Co.: No site, no date, no collr. (5 USNM; 4 UW;
8 ASP; 3 SDSU). No site, no date, F.C. Bowditch (8 MCZ). Oregon: Crook Co.: 5 mi. S. Suplee, Weburg Ranch, hot
springs, temp. 100 degrees F., 62-09-07, K. Goeden (5 ORSU). Harney Co.: Hot Spgs. SE shore Harney Lake,
51-06-20, B. Malkin (5 UWA; 3 CFMNH). 1 mi. S. Harney Lake, hot springs, 56-05-18, J.D. Lattin (7 ORSU). 1/2
mi. S. Harney Lake, margins of hot springs, 61-06-30, K. Goeden (5 ORSU). 20 mi. W. Malheur Lake, hot springs,
56-05-18, K. Goeden (2 ORSU). Lake Co.: fresh pool, SE shore L. Albert, 50-07-17, H.B. Leech (1 CAS). Abert
Lake, 57-04-28, J. Schuh (3 UWA; 3 JS). Malheur Co.: Sucker Cr. at hiway. 95, 56-07-20, H.B. Leech (2 CAS).
Washington: Grant Co.: Grand Coulee, Tule Lake, 46-05-11, M.H. Hatch (1 UWA). Upper Grand Coulee, 36-04-26,
M.H. Hatch (1 UWA). Pacific Co.: Tokeland, 29-07-10, no collr. (13 UWA). Skagit Co.: Anacortes, brackish pond,
61-05-20, D.V. McCorkle (2 UWA).

5. Ochthebius sierrensis new species

Map: Figure 99A
Paratypes: 15

United States: California: Calaveras Co.: Mokelumne Hill, 10-07-18, F.E. Blaisdell (5 CAS). Fresno Co.: Squaw
Valley Cr., 55-06-26, P.S. Bartholomew (7 CAS). Kings River Camp, 50-08-23, P.S. Bartholomew (3 CAS).

Quaest. Ent., 1980, 16 (1,2)

508

Perkins

6. Ochthebius lineatus LeConte

Map: Figure 107

Specimens examined: 1,690

Canada: Alberta: Medicine Hat, many dates, F.S. Carr (24 CAS; 2 USNM; 5 UWA; 4 MCZ; 8 UA). Medicine
Hat, 24-08-31, H. Wenzel (20 OSU). Highwood Valley, cataract Creek, 64-07-16, H.B. Leech (1 CAS). Hussar,
28-05-20, O. Bryant (5 CAS). Tilley, 34-06-25, J. Carr (3 CAS). Castor, no date, no collr. (1 OSU). British Columbia:
Kamloops, Lac du Bois, Lone Rock Narrows Pool, 43-07-08, G. J. spencer (2 CAS). Creston, Goat River, many dates,
G. Stace-Smith (3 UWA; 1 1 UBC). Copper Mtn., 30-08-24, G. Stace-Smith (2 CNC; 1 UBC). Sumqierland, 33-06-01,
A.N. Gartrell (1 CNC). Kamloops, no date, Wickham (1 ASP). 17 mi. W. Hedley, 59-05-31, R.E. Leech (2 CNC).
Manitoba: Winnipeg, 16-09-23, J.B. Wallis (3 CNC). Stonewall, 20-05-02, J.B. Wallis (1 CNC). St. Norbert, 17-09-22,
J.B. Wallis (1 CNC). Saskatchewan: Saskatoon, 70-09-19, E.J. Kiteley (2 EJK). Elbow, 50-06-03, A.R. Brooks (1
CNC).

Colombia: Magdalena: 8 km. E. Barranquilla, 69-03-19, P. & P. Spangler (5 USNM). Atlantico: Barranquilla,
69-03-18, P. & P. Spangler (5 USNM).

Mexico: Baja California: Arroyo de la Purisima, 1 mi. upstream from town, 58-12-27, H.B. Leech (3 CAS).
Mexicali, 42-10-28, no collr. (2 USNM). Chihuahua: Cd. Jiminez., 64-06-26, P.J. Spangler (1 USNM). Nayarit: Tepic,
53-09-24, B. Malkin (1 USNM). Oaxaca: Salina Cruz, 64-07-23, P.J. Spangler (13 USNM). Tehuantepec, 64-07-23,
P.J. Spangler (1 USNM). Sinaloa: Los Mochis, 22-06-13, C.T. Dodds (76 CAS). Los Mochis, 13 mi. N., 64-08-07,
Chemsak & Powell (1 UBC). Sonora: Hermosillo, 53-07-16, B. Malkin (93 CAS). Hermosillo, 55-05-25, B. Malkin (1
UBC). Alamos, 63-02-22, P.H. Arnaud, Jr., (92 CAS). 7 mi. SE Alamos, 71-1 1-27, K. Stephan (6 KS). Alamos, 7 mi.
W., 64-08-08, Chemsak & Powell (1 UBC). 40 mi. SE Guaymas, no date, K. Stephan (6 KS). 16 mi. NE Cd. Obregon,
61-05-14, Howden & Martin (1 CNC). 10 mi. NE Cd. Obregon, 64-08-10, Howden & Lindquist (1 CNC).

United States: Arizona: Cochise Co.: Wilcox Playa, 69-1 1-02, K. Stephan (1 KS). Gila Co.: Globe, 49-08-01, F.H.
Parker (8 UA). Porter Springs, Roosevelt Lake, 28-02-22, no collr. (4 CNC). Maricopa Co.: Phoenix, no date, no collr.
(4 OSU). Navajo Co.: Winslow, no date, Wickham (1 MCZ; 2 USNM). Pima Co.: Tucson, no date, Hubbard &
Schwarz (1 USNM). Colossal Cave Park, 68-02-18, K. Stephan (2 KS). Santa Cruz Co.: Patagonia, 36-07-01, E.S.
Ross (1 CAS). Yuma Co.: Tacna, no date, Hubbard & Schwarz (1 USNM). Yuma, 59-06-01, D. Muse (1 UA). Yuma,
59-03-30, D. Muse (4 UA). Yuma, 61-07-24, D. Tuttle (2 UA). Alamo Crossing, u. v. It., 62-07-14, Werner & Johnson
(2 UA). Unspecified Co.: No site, no date, no collr. (2 CAS; 1 ASP; 1 MCZ). California: Alameda Co.: 10 mi. E.
Livermore, 59-03-14, D. Burdick (1 UBC). No site, 06-08-01, F. Nunenmacher (1 CFMNH). Colusa Co.: Indian Cr.,
1.5 mi. along road to Cooks Springs, SW of Lodoga, 71-10-10, H.B. Leech (1 CAS). Contra Costa Co.: No site,
38-05-01, J. Blum (3 OSU). Imperial Co.: Imperial Valley, 11-02-01, F.E. Blaisdell (22 CAS). Imperial Cr., Imperial
Valley, 11-02-01, no collr. (4 USNM). El Centro, 27-12-06, F.E. Blaisdell (5 CAS). El Centro, 1 1-01-01, J.C. Bridwell
(5 USNM). La Puerta, 11-02-01, no collr. (39 CAS). Seeley, 45-02-16, Anderson & Hanson (4 USNM). No site,
22-06-06, F.E. Blaisdell (3 CAS0. Kern Co.: Poso Creek, no date, no collr. (8 CAS). Lake Co.: Hidden Lake, 4 mi. NW
of Lakeport, 55-08-05, H.B. Leech (1 CAS). Rocky Point, Clear Lake, 46-05-08, H.P. Chandler (1 CAS). L. Pillsbury,
Eel River, 2000’, 46-10-09, H.P. Chandler (1 CAS). Lassen Co.: Martins Springs, 22-08-08, J.O. Martin (1 CAS). Los
Angeles Co.: Tejon Pass, 18-07-28, J.O. Martin (12 CAS). Los Angeles, no date, no collr. (1 CAS). No site, no date, no
collr. (1 CAS). Marin Co.: Dipsea, 08-06-01, F.E. Blaisdell (1 CAS). No site, no date, no collr. (1 CAS). Mono Co.:
Poore Lake, 7514’, 63-08-14, H.B. Leech (5 CAS). Overflow pond N. site, Poore Lake, 7200’, 63-08-14, H.B. Leech (5
CAS). Round pond on ridge S. of Leavitt Mdw., 7500’, 63-08-13, H.B. Leech (1 CAS). W. Walker River, 52-08-16,
P.S. Bartholomew (2 CAS). Orange Co.: Laguna Beach, rock crevice, tidewater, 31-02-12, F.E. Winters (2 CAS).
Riverside Co.: Colorado River, no date, F.E. Winters (10 CAS). Palm Canyon, 16-04-15, J.O. Martin (1 CAS).
Riverside, no date, F.E. Winters (4 CAS; 1 OSU; 1 MCZ). San Bernardino Co.: San Bernardino Mts., no date, no collr.
(1 CAS). Needles, no date, no collr. (5 CAS). Santa Inez Mts., Santa Barbara, no date, F.E. Winters (I OSU). The
Needles, no date, no collr. (1 ASP). Needles, no date, Wickham (4 MCZ). San Francisco Co.: No site, 15-03-21, no
collr. (1 CAS). San Joaquin Co.: Near Lodi, 31-04-20, F.E. Blaisdell (1 CAS). Santa Barbara Co.: Santa Barbara, no
date, F.E. Winters (2 CAS). Shasta Co.: Hat Creek R.S., 3000’, 47-06-28, H.P. Chandler (1 CAS). Siskiyou Co.: 6 mi.
S. Macdoel, 58-03-24, J. Schuh (1 JS). 6 mi. S. Macdoel, edge of pond, 66-10-07, J. Schuh (1 JS). Sutter Co.: 8 mi. W.
Live Oak, 62-05-30, J. Doyen (1 UCB). Tulare Co.: Kern River, 9.5 road mi. N. of Kernville, 70-03-25, H.B. Leech (1
CAS). Colorado: Routt Co.: Steamboat Springs, 47-07-01, O. Bryant (1 CAS). Mesa Co.: Black Ridge, 5 mi. N. Glade
Park, 68-07-14, H.F. Howden (1 CNC). Moffat Co.: Deception Creek, 2 mi. E. Maybell, 5910’, 67-07-13, H.B. Leech
(4 CAS). Weld Co.: Greeley, no date, no collr. (1 USNM). Idaho: Bear Lake Co.: Montpelier, swamp, 52-07-10, B.
Malkin (2 UWA; 2 CFMNH). Bonner Co.: Pen d’Oreille R., Sand Point, 37-06-20, no collr. (9 UWA). Cassia Co.:
Sublett Reservoir, 52-07-13, B. Malkin (60 CAS, 3 UWA, 3 CFMNH). Custer Co.: Salmon River, 12 mi. N. Challis,
52-07-24, B. Malkin (8 UWA; 8 CFMNH). Jefferson Co.: Camas Wildlife Refuge, 52-07-27, B. Malkin (3 UWA; 3
CFMNH). Twin Falls Co.: Magic Hot Springs, 52-07-20, B. Balkin (2 UWA; 2 CFMNH). Valley Co.: Donnelly,
52-08-30, W.F. Barr (2 Ul; 1 UWA). Kansas: Logan Co.: McAllister, 56-08-29, P.J. Spangler (84 USNM). Montana:
Dawson Co.: Glendive, no date, Hubbard & Schwarz (4 USNM; 16 CAS). Flathead Co.: Kalispell, 20-06-13, Wickham

Western Hemisphere Hydraenidae

509

(12 USNM; 4 MCZ). Madison Co.: Ziegler Hot Springs, 52-07-27, B. Malkin (10 CFMNH). Nebraska: Thomas Co.:
Neb. Nat’l, Forest, 2.5 mi. W. Halsey, 67-07-16, H.B. Leech (1 CAS). Nevada: Ormsby Co.: Carson City, no date,
Wickham (1 MCZ). New Mexico: Bernalillo Co.: Albuquerque, no date, no collr. (2 CFMNH; 2 UW; 2 CU; 1 ASP; 13
CAS). Albuquerque, no date, Wickham (2 USNM). No site, no date, no collr. (12 USNM; 5 UW; 4 CFMNH; 8 OSU;
2 CNC; 3 CU; 13 MCZ). Dona Ana Co.: Mesilla Dam, 24-04-25, J. O. Martin (22 CAS). North Dakota: Adams Co.:
No site, 63-09-04, R. Gordon & R. Post (1 RG). Benson Co.: Pleasant Lake, springfed pond, 68-08-16, R. Gordon (1
USNM). Bottineau Co.: Lake Metigoshe, 63-05-23, R. Gordon (4 RG). No site, 62-07-15, R. Gordon (1 RG). Burke
Co.: No site, 63-05-23, R. Gordon (24 RG). Burleigh Co.: No site, 63-09-03, R. Gordon & R. Post (1 RG). Cass Co.:
Fargo, 66-07-30, R. Gordon (3 RG). Divide Co.: No site, 63-05-23, R. Gordon (1 RG). Dunn Co.: Killdeer Mts.,

63- 05-22, R. Gordon (1 RG). Eddy Co.: Lake Coe, 66-06-24, R. Gordon (1 RG). Foster Co.: No site, 63-05-03, R.
Gordon (5 RG). Grand Forks Co.: 5 mi. S. Niagara, 66-07-08, R. Gordon (1 RG). Northwood, Goose River, 66-07-08,
R. Gordon (22 RG; 1 CAS). Grant Co.: Lake Tschida, 66-05-21, R. Gordon (3 RG). Hettinger Co.: No site, 62-09-12,
R. Gordon (1 RG). Mchenry Co.: No site, 62-09-11, R. Gordon & R.L. Post (1 RG; 2 CAS). Ransom Co.: T.135N
R.52W Sec. 14NW, 66-08-05, R. Gordon (1 RG). Renville Co.: Sherwood, 66-05-29, R. Gordon (22 RG). Richland
Co.: Mirror Pool, 68-08-22, R. Gordon (1 USNM). T.135N R.52W Sec.5, 68-08-22, no collr. (13 USNM). No site,

64- 08-19, R. Gordon (3 RG). Rolette Co.: Dunseith, junct. Hwy. 3 & 43, .5 mi. W., 70-06-06, R. Gordon (2 RG).
Sargent Co.: Tewaukon Ref. Headq. spring, 68-08-23, R. Gordon (6 USNM). Slope Co.: Chalky Buttes, 65-06-07, W.
Kotchman (2 CAS). No site, 62-09-13, R. Gordon & R.L. Post (1 RG; 5 USNM; 2 CAS). Traill Co.: Mayville, Goose
River, 65-09-24 (3 RG). Wells Co.: Fessenden, James River, 66-06-24, R. Gordon (2 RG). Williams Co.: Willist’n,
09-06-08, Wickham (1 UW; 1 USNM; 12 CAS). Willist’n, 33-06-08, Wickham (1 RG). Oklahoma: Woods Co.: 3 mi.
W. Waynoka, old road to Herman, 67-08-11, H.B. Leech (2 CAS). Oregon: Benton Co.: Corvallis, small pond,
56-04-08, K. Goeden (1 ODA). Harney Co.: Steens Mts, Fish Lake, 7500’, 51-06-26, B. Malkin (1 UWA). Klamath
Co.: Bly Mts., 45-06-13, K.M. Fender (1 UWA). Sprague R., 12 mi. E. Chiloquin, 51-07-03, B. Malkin (26 UWA).
Bly, 45-06-13, K.M. Fender (3 UWA). Barkley Springs, 59-09-08, J. Schuh (2 UWA). 8 mi. NE (air) Klamath Falls,
black-lite trap, 65-07-03, K. Goeden (1 ODA). Hog Cr., E. side of Solomon Flat, 68-04-06, J. Schuh (15 JS). Poe
Valley, temporary pond, 66-05-13, J. Schuh (82 JS). Klamath Falls, Modoc Point, in pond, 55-06-01, J. Schuh (1 JS).
Klamath Falls, above Geary Ranch, sweeping swamp, 61-05-17, J. Schuh (2 JS). Barkley Springs, 59-09-08, J. Schuh (5
JS). Kirk, Williamson River, shore, 66-10-02, Schuh, Scott & Gray (1 JS). Upper Klamath Marsh, Jackson Cr.,

65- 09-25, J. Schuh (1 JS). Head of Spring Cr., 65-08-16, J. Schuh (1 JS). Sprague River, 12 mi. E. Chiloquin,
51-07-01, B. Malkin (24 CFMNH). Barkley, 74-07-03, Gordon & Schuh (1 RG). Spring Creek Campground, 74-07-02,
R. Gordon (2 RG). Chewaucan River near Valley Falls, 39-08-16, Gray & Schuh (1 CAS; 1 ORSU). Lakeview,
51-06-28, B. Malkin (1 UWA). Chewaucan R., dam site, 55-06-18, J. Schuh (1 JS). Chewaucan R. near Valley Falls,
55-06-06, J. Schuh (1 JS). Malheur Co.: Sucker Creek Canyon, 51-06-18, B. Malkin (3 CFMNH; 5 UWA). Owhhee
River, 3 mi. SE Rome, 3500’, 64-07-14, T. Schuh & J. Lattin (1 ORSU). Wasco Co.: The Dallas, 54-04-07, S. & M.
Sargent (1 UWA). Yamhill Co.: Dayton, 41-09-07, K.M. & D M. Fender (2 UWA). McMinnville, 48-07-15, K.M. &
D.M. Fender (4 UWA). 4 mi. S. Newberg, black-lite trap, 69-08-11, no collr. (1 ODA). South Dakota: Beadle Co.:
Wolsey, 3 mi. NW. 40-06-20, G. Spawn (4 SDAU). Brown Co.: Houghton, 6 mi. SE 40-06-21, H. Severin (2 SDSU).
Aberdeen, 39-09-24, G. Spawn (11 SDSU). Groton, 17 mi. N„ 40-06-20, H. Severin (6 SDSU). Houghton, 8 mi. W„
41-06-14, H. Severin (3 SDSU). Brookings Co.: Lake Oakland, 4 mi. N., 39-08-11, G. Spawn (60 SDSU). Day Co.:
Roslyn, 39-09,14, H. Severin (3 SDSU). Waubay Refuge, alkalia water, 40-06-22, H. Severin (2 SDSU). Deuel Co.:
Clear Lake, 39-09-15, H. Severin (1 SDSU). Fall River Co.: Hot Springs, 6 mi. S„ 40-06-22, H. Severin (1 SDSU).
Hot Springs, 61-07-09, H. & A. Howden (1 CNC). Angostura Dam, S. of Hot Springs, 68-07-06, H.F. Howden (1
CNC). Smithwick, 40-06-21, H. Severin (3 SDSU). Gregory Co.: Burke, 40-06-1 1, H. Severin (1 SDSU). Haakon Co.:
Phillip Junction, 40-09-07, H. Severin (6 SDSU). Dam Phillip, 40-09-07, H. Severin (2 SDSU). Jackson Co.: Belvidere,
10 mi. E., 39-09-24, G. Spawm (13 SDSU). Kingsbury Co.: Arlingon, pothole, 39-06-19, H. Severin (6 SDSU).
Lawrence Co.: Spearfish Creek, 3 mi. N. Spearfish, 71-06-09, E.U. Balsbaugh, Jr. (1 SDSU). Lincoln Co.: Canton, 1
mi. W., gravel pit, 40-08-20, G. Spawn (1 SDSU). Lyman Co.: Vivian, Reeds Ranch, 40-07-11, H. Severin (4 SDSU).
Kennebec, 2 mi. W., 40-06-20, H. Severin (8 SDSU). McPherson Co.: Leola, 14 mi. NW. 40-06-25, H. Severin (13
SDSU). Mellette Co.: Wood, 39-07-23, H. Severin (37 SDSU). Pennington Co.: Black Hills, Cheyenne Xing, 66-06-18,
R. Gordon (2 RG). Hill City, 10 mi. S„ 40-06-22, H. Severin (1 SDSU). Dam Wall, 40-09-07, H. Severin (2 SDSU).
Larive Lake, cold brook, 40-06-22, H. Severin (1 SDSU). Roberts Co.: Ortley, 7 mi. N., 40-07-24, H. Severin (3
SDSU). Todd Co.: 9 mi. E. Rosebud, 40-09-05, H. Severin (2 SDSU). Yankton Co.: 3 mi. W. Mission Hill, 40-08-05,
H. Severin (3 SDSU). Texas: El Paso Co.: El Paso, 89-11-22, Fall (1 CAS). El Paso, 42-02-14, no collr. (1 USNM). El
Paso, no date, no collr. (2 CU; 5 CAS). Jeff Davis Co.: Davis Mts., 71-02-01, K. Stephan (2 KS). Kimble Co.: Junction,
71-02-01, K. Stephan (1 KS). Uvalde Co.: Sabinal, 10-03-01, F.C. Pratt (1 USNM). Utah: Beaver Co.: Milford, no
date, Wickham (2 USNM; 3 CAS; 1 MCZ). Cache Co.: Logan Canyon, 7200’, 73-07-28, R. Gordon (1 RG). Duchesne
Co.: Myton, no date, no collr. (2 CNC; 5 CAS). Utah Co.: Utah Lake, east side, 4000’, 41-06-14, H.P. Chandler (12
CAS). Payson Canyon, 7000’, 41-06-21, H.P. Chandler (4 CAS). Wayne Co.: Hanksville, 68-08-01, H.F. Howden (10
CNC). 12 mi. S. Hanksville, 68-07-22, H.F. Howden (2 CNC). Washington: Kittitas Co.: Ellensberg, 32-07-19, M.H.
Hatch (2 UWA). Ellensberg, 54-09-26, B. Malkin (4 CFMNH). Lincoln Co.: Grand Coulee, Tule Lake, 46-05-11,
M.H. Hatch (1 UWA). Grand Coulee, Dry Falls, 37-05-01, M.H. Hatch (1 UWA). Grand Coulee, Dry Falls, 47-05-04,

Quaest. Ent., 1980, 16 (1,2)

510

Perkins

M.H. Hatch (1 UWA). Spokane Co.: Spokane, 32-08-26, M.H. Hatch (8 UWA). Mead, 32-08-26, M.H. Hatch (3
UWA). Chatteroy, 32-08-26, M.H. Hatch (1 UWA). Cheney, Turnbull Slough, 47-05-30, M.H. Hatch (3 UWA).
Whitman Co.: Lancaster, Palouse River, 32-08-27, M.H. Hatch (2 UWA). Wisconsin: Bayfield Co.: Bayfield, no date,
Wickham (1 RG). Wyoming: Bighorn Co.: Shell Cr., mouth of Shell Canyon at Shell, 4230’, 64-07-25, H.B. Leech (10
CAS). Crook Co.: Devils Tower N. Mon., Belle Fourche River, 62-08-13, P.J. Spangler (57 USNM). Fremont Co.:
Burris, 10 mi NW E. fork Wind River, 62-08-23, P.J. Spangler (2 USNM). Goshen Co.: Culvert under Hwy. 26, 3.5
mi. W. of town of Fort Laramie, foul pool, 65-08-19, H.B. Leech (8 CAS). N. Platte River, old Hwy. bridge, 5.3 mi. E.
town of Fort Laramie, 65-08-18, H.B. Leech (1 CAS). Hot Springs Co.: Thermopolis, 52-08-03, B. Malkin (1
CFMNH). Natrona Co.: Middle Casper Cr. at Hwy. 20, ca 2.5 mi. Se Natrona, 65-08-20, H.B. Leech (4 CAS).
Badwater Cr. at Badwater, NW of Arminto, 65-08-21, H.B. Leech (1 CAS). Dugout Cr., 8.5 mi. NW of Midwest,
64-07-27, H.B. Leech (4 CAS). Platte Co.: Stream under Hwy. 87, 5.8 mi. S. of Glendo, 64-07-29, H.B. Leech (1
CAS). Horseshoe Cr., 2 mi. S. Glendo, 64-07-29, H.B. Leech (1 CAS). Sheridan Co.: Bighorn Nat’l. For. nr. Dayton,
Isaac Walton Picnic Area, 62-08-14, P.J. Spangler (2 USNM). Sweetwater Co.: Ox-bow cut-off of Bitter Cr., 10 mi. W.
Rock Springs, Hwy. 30, 65-08-23, H.B. Leech (1 CAS). Yellowstone National Park: Yellowstone Park, 8000’, no date,
no collr. ( 1 CAS).

7. Ochthebius marinus (Paykull)

Map: Figure 109
Specimens examined: 702

Canada: Alberta: 6 mi. S. Pincher Creek, 71-08-01, P.D. Perkins (1 PDP). Medicine Hat, 25-05-08, F.S. Carr (4
UA; 1 CAS). Medicine Hat, 34-06-24, J. Carr (1 CAS). Medicine Hat, 24-08-31, no collr. (I OSU; 1 PDP). Medicine
Hat, 28-08-28, no collr. (7 USNM). Highwood Valley, Cataract Cr., 64-07-16, H.B. Leech (3 CAS). Tofield, 24-05-11,
O. Bryant (1 CAS). Edmonton, 24-09-01, O. Bryant (1 CAS). High River, 27-06-01, O. Bryant (1 CAS). Calgary,
45-06-10, E.J. Kiteley (1 EJK). Castor, no date, no collr. (1 OSU). Bittern Lake, 61-08-15, A.M. Brooks (1 CNC).
Lusk Creek, 1 mi. E. Kananaskis, F.E.S., 70-08-22, Lindquist (1 CNC). British Columbia: Kamloops, Old Stove Pond,
Lac du Bois, 43-07-18, G.J. Spencer (3 CAS). Kamloops, Lac du Bois, Lone Rock, Narrows Pool, 43-07-08, G.J.
Spencer (2 CAS). Upper Hat Cr., roadside pool, China Farm, 33-08-29, G. Spencer (1 CAS). Savona Road, 33-07-07,
A. Thrupp (1 CAS). Lillooet Dist., Alkali Lake, 30 mi. S. Williams Lake, 71-07-24, P.D. Perkins (5 PDP). Kamloops,
no date, Wickham (1 USNM). Summerland, 32-05-28, A.N. Gartrell (1 CNC). Manitoba: Churchill, 30-06-25, O.
Bryant (1 CAS). Aweme, 20-07-08, J.B. Wallte (1 CAS). Aweme, 27-08-05, E. Criddle (1 USNM). Treesbank, 4 mi.
W. Hwy. 344, 68-08-14, R. Gordon (3 USNM). Churchill, 37-08-18, W.J. Brown (17 CNC). Husavick, 16-07-17, J.B.
Wallis (3 CNC). Winnipegosis, no date, J.B. Wallis, (1 CNC). Winnipeg, 22-08-24, J.B. Wallis (1 CNC). Stonewall,
20-05-02, J.B. Wallis (1 CNC). Churchill, 52-08-02, J.G. Chillcott (3 CNC). Onah, 18-07-11, J.B. Wallis (1 MCZ).
Winnipeg Beach, 10-07-11, J.B. Wallis (1 MCZ). Aweme, 70-06-09, R. Gordon (1 RG). Saskatchewan: Yorkton,
47-07-27, C.C. Shaw (2 CAS). Saskatoon, 70-09-19, E.J. Kiteley (4 EJK). Christopher Lake, 46-07-30, E.J. Kiteley (1
EJK). Great Deer, 49-04-25, J.R. Vockeroth (4 CNC). Elbow, 60-06-03, A.R. Brooks (1 CNC). Cochin, 59-05-20, A.R.
Brooks (1 CNC).

United States: California: Modoc Co.: Menlo Baths, 4 mi. SE of Eagleville, 4550’, 66-08-28, H.B. Leech (1 CAS).
Mono Co.: Mammoth, 45-09-15, G.P. Mackenzie (5 CAS). Siskiyou Co.: Indian Tom Lake, 67-05-08, J. Schuh (86 JS).
Indian Tom Lake, 65-09-15, J. Schuh (43 JS). Indian Tom Lake, 66-09-27, J. Schuh (12 JS). Willow Cr., 55-07-14, J.
Schuh (1 JS). Tulare Co.: Beach Ridge, 9200’, 65-07-30, D.R. Schuh (2 JS). Colorado: Alamosa Co.: 9 mi. E. of
Hooper, 1 mi. W. of Dollar Lake, drainage ditch, 65-08-13, H.B. Leech (14 CAS). Alamosa, no date, F.C. Bowditch (1
MCZ). Costilla Co.: Garland, no date, Hubbard & Schwarz (1 CAS). Garland, no date, no collr. (2 ASP). Garland, no
date, F.C. Bowditch (1 MCZ). Grand Co.: Gore Pass, 49-08-15, O. Bryant (2 CAS). Larimer Co.: No. Park, 8000’,
33-08-18, E.B. Andrews (1 CAS). R. Mt. Natl. Park, 7900', 33-10-08, E.B. Andrews (1 CAS). Rocky Mtn. N.P.,
33-07-28, G. & J. Sperry (1 CAS). Estespark, R. Mt. Nat’l. Park, 7900’, 33-08-10, E.B. Andrews (1 CU). R. Mt.
Nat’l. Park, Beaver Lk. 33-07-28, G. & J. Sperry (2 MCZ). Park Co.: 1.5 m. E. of Hartsel, weedy pool, 65-08-15, H.B.
Leech (1 CAS). Saguache Co.: Mineral Hot Springs, ca 7700’, 65-08-13, H.B. Leech (31 CAS). Saguache, 52-08-18, B.
Malkin & Vet (7 CFMNH). Idaho: Bannock Co.: Pocatello, no date, no collr. (1 USNM). Bingham Co.: No site, no
date, Hubbard & Schwarz (1 USNM). Montana: Blaine Co.: Bear Paw Mt., no date, Hubbard & Schwarz (1 USNM).
Nevada: Elko Co.: 9 mi. NE Montello, Thousands Springs Cr., route 30, 69-08-26, H.B. Leech (5 CAS). Lincoln Co.:
Upper Pahranagat Lake, 71-08-05, P.D. Perkins (12 PDP). North Dakota: Bottineau Co.: No site, 63-05-23, R. Gordon
(1 CAS; 1 USNM). Lake Metigoshe, 63-05-23, R. Gordon (32 USNM). Burke Co.: No site, 66-05-23, R. Gordon (4
CAS). No site, 63-06-23, R. Gordon (2 USNM). Dunn Co.: Killdeer Mts., 63-05-22, R. Gordon (1 RG). Foster Co.: No
site. 63-05-01, R. Gordon (2 USNM; 1 CAS). Grant Co.: Lake Tschida, 66-05-21, R. Gordon (1 USNM; I CAS).
Griggs Co.: Binford, 66-06-02, R. Gordon (5 USNM). Mchenry Co.: No site, 62-09-11, R. Gordon & R. Post (3
USNM). Nelson Co.: No site, 63-06-20, R. Gordon (2 USNM). Pierce Co.: No site, 63-05-14, R. Gordon (3 USNM).
Ramsey Co.: Devils Lake, 17-07-23, R.T. Young (19 USNM). Renville Co.: Sherwood, 13 mi. west, 66-05-29, R.
Gordon (1 USNM). Rolette Co.: Dunseith, jet. Hwy. 3 & 43, 0.5 mi. W. 70-06-06, R. Gordon (3 RG). Slope Co.: Burn

Western Hemisphere Hydraenidae

511

Coal Vein, 65-06-07, L. Grochowski (1 USNM). Chalky Buttes, 65-06-07, W. Kotchman (1 USNM). Oregon: Douglas
Co.: Roseburg, 59-04-24, H. Foster (1 ODA). Harney Co.: Malheur Lake, 51-06-21, B. Malkin (119 UWA; 28
CFMNH). Steens Mts., Fish Lake, 7500’, 51-06-26, B. Malkin (3 UWA). Hot Spgs., SE shore of Harney Lake
51-06-20, B. Malkin (9 UWA; 1 CFMNH). Fish Lake, Steens Mts., 58-08-16, J.H. Baker (1 JS). Steens Mts., Fish
Lake, 7500’, 51-06-22, B. Malkin (3 CFMNH). Jackson Co.: Ashland, at light, 52-07-08, Black & Davis (1 ODA).
Klamath Co.: Barkley Springs, 59-09-08, J. Schuh (3 JS; 3 UW). Dairy, 38-06-15, M.H. Hatch (4 UWA). Klamath
Falls, 50-09-03, B. Malkin (2 UWA). Klamath Falls, light trap, 60-06-08, J.D. Vertrees (1 UWA). Lower Klamath
Lake, 55-07-03, J. Schuh (3 UWA). Klamath Falls, Barkley Springs, 55-06-01, J. Schuh (1 UWA). Poe Valley,
temporary pond, 66-06-05, J. Schuh (4 JS). Lower Klamath Lake, roadside ditch, 66-06-06, J. Schuh (18 JS). Klamath
Falls, above Geary Ranch, Sweeping swamp, 61-05-17, J. Schuh (1 JS). Lower Klamath Lake, in alkaline lake,
58-05-30, J. Schuh (1 JS). Klamath Falls, Poe Valley, in pond, 55-05-27, J. Schuh (1 JS). Near Gerber Dam, 57-06-16,
J. Schuh (1 JS). Upper Klamath Lake, Geary Canal, 57-04-22, J. Schuh (1 JS). Klamath Falls, Algoma, mech. trap,
55-07-13, J. Schuh (1 JS). Upper Klamath Lake, along shore line, 55-04-24, J. Schuh (1 JS). Klamath Falls, lite,
67-05-15, J. Schuh (3 JS). Lake Co.: Abert lake, 57-04-28, J. Schuh (1. JS). Malheur Co.: Sheepshead Mts., 51-06-18,
B. Malkin (7 UWA). South Dakota: Beadle Co.: Wolsey, 3 mi. NW, 40-06-20, G. Spawn (1 SDSU). Brookings Co.:
Brookings, light trap, 56-07-18, H. Severin (2 SDSU). Brown Co.: Groton, 17 mi. N., 40-06-20, H. Severin (2 SDSU).
Houghton, 8 mi. W., 41-06-14, H. Severin (1 SDSU). Day Co.: Waubay Refuge, alkali water, 40-06-22, H. Severin (19
SDSU). Andover, 2 mi. E„ 40-06-26, G. Spawn (1 SDSU). Roslyn, 39-09-14, H. Severin (2 SDSU). McPherson Co.:
Eureka, 40-06-25, H. Severin (2 SDSU). Utah: Millard Co.: Shore of Pruess Lake, 64-08-04, H.B. Leech (14 CAS).
Rich Co.: Randolph, 55-07-14, S.L. Wood (1 CNC). Washington: Pend Oreille Co.: Diamond L., 7 mi. NE Camden,
34-08-13, M.H. Hatch (1 UWA). Spokane Co.: Deer Park, 32-08-25, M.H. Hatch (1 UWA). Wyoming: Albany Co.:
Laramie, 94-03-13, Hubbard & Schwarz (6 USNM). Rock Creek, 5000’, 41-08-24, H.P. Chandler (1 CAS). Johnson
Co.: S. Fork of Crazy Woman Cr., 64-07-27, H.B. Leech (1 CAS). Sweetwater Co.: 10 mi. W. Rock Springs, Ox-bow
cut-off of Bitter Cr., 65-08-23, H.B. Leech (1 CAS). Yellowstone National Park: Natl. Park, no date, Hubbard &
Schwarz (1 USNM). Yellowstone Natl. Park, canyon, 37-09-01, M.H. Hatch (14 UWA).

8. Ochthebius uniformis new species

Map: Figure 1 17C
Paratypes: 80

United States: California: Del Norte Co.: 2 mi. S. Crescent city, roadside pond, 67-03-29, Schuh & Vertrees (23
JS). Humboldt Co.: Areata, no date, Van Dyke (1 CAS). Marin Co.: Dipsea, no date, F.E. Blaisdell (1 CAS). Dillon
Beach, pools, foot of Sand Point Dunes, 63-06-24, H.B. Leech (1 CAS). Pt. Reyes Penin., no date, D. Giuliani (2 CAS).
Whale Beach, 8 mi. W. Inverness, 62-08-18, J. Doyen (1 UBC). San Francisco Co.: San Francisco, 09-09-09, F.E.
Blaisdell (4 CAS). San Francisco, 09-03-28, F.E. Blaisdell (7 CAS). San Francisco, 16-09-16, Van Dyke (10 CAS). San
Francisco, no date, E.S. Ross (1 CAS). San Luis Obispo Co.: Lopez Canyon Dam outlet, 70-09-05, P.D. Perkins (1
PDP). Sonoma Co.: 2.8 mi. S. & E. Bodega Bay, 63-07-01, H.B. Leech (1 CAS). Oregon: Harney Co.: Steens Mts.,
Fish Lake, 7500’, 51-06-22, B. Malkin (8 CFMNH). Lane Co.: 7 mi. S. Florence, pond near beach, 62-05-01, Vertrees,
Hansen, Carter & Schuh (10 JS). 7 mi. S. Florence, Siltcoos Beach, 62-05-01, Vertress, Hansen, Carter & Schuh (8
JS). Washington: Pacific Co.: Seaview, 32-07-25, no collr. (1 UWA).

9. Ochthebius borealis new species

Map: Figure 1 1 7C
Paratypes: 362

Canada: British Columbia: Fernie, 34-07-26, H.B. Leech (6 CAS). Hosmer, Hosmer Cr., 49-07-08, H.B. Leech (2
CAS). Nation River Dist., 40-06-25, G.B. Leech (2 CAS). Skunk Lake, Manson R. Dist., 40-07-22, G.B. Leech (1
CAS). McNair L., 5.5 mi. W. Skookumchuck, E. Kootenays, 56-07-17, H.B. Leech (1 CAS).

Mexico: Baja California: Sierra San Pedro Martir, La Grulla, 6900’, 53-06-12, P.H. Arnaud, Jr. (12 CAS).

United States: California: Fresno Co.: Kaiser Peak Meadow N. of Huntington L., 8420’, 71-08-25, H.B. Leech (1 CAS).
Glenn Co.: NW corner of Glenn co., 4.5 mi. S. of Mendocino Pass, pool in stream, grassy slope, 6500', 60-07-29, H.B.
Leech (17 CAS). Plaskett Mdws., stream from N. entering lower Plaskett Lake, 6000’, 60-07-28, H.B. Leech (7 CAS).
Lassen Co.: Martins Spgs., 22-08-08, J.O. Martin (12 CAS). Madera Co.: Nidiver Lakes, 10,000’, 51-07-05, P.H.
Raven (1 CAS). Modoc Co.: 3 mi. S. Lake City, Soldier Cr., 66-08-25, H.B. Leech (1 CAS). Mono Co.: Round pond on
ridge south of Leavitt Mdw., 7500’, 63-08-13, H.B. Leech (5 CAS). Pond on ridge S. of Leavitt Meadow, 7500’,
62-08-10, H.B. Leech (13 CAS). Poore Lake, 7514’, 63-08-14, H.B. Leech (1 CAS). Napa Co.: Burton Cr., Pope
Valley, 64-05-10, H.B. Leech (1 CAS). Nevada Co.: Truckee, 5800’, no date, Wickham (3 USNM; 4 MCZ). Webber
Lake to Meadow Lake, 64-08-22, E. Ball, Jr., (1 JS). Sagehen Cr. nr. Hobart Mills, 66-06-26, W.J. Turner (7 UCB).
Placer Co.: Lake Tahoe, 19-08-15, J.O. Martin (14 CAS). Lake Tahoe, no date, A. Koebele (1 CAS). No site, no date.

Quaest. Ent., 1980, 16 (1,2)

512

Perkins

A. Koebele (1 USNM). Riverside Co.: Riverside, no date, F.E. Winters (1 CAS). S. Cal., no date, no collr. (1 USNM).
San Bernardino Co.: San Bernardino Mts., no date, F.E. Winters (1 CAS). Bear Lake, 17-07-02, J.O. Martin (10 CAS,
1 CU). Santa Clara Co.: Stanford Univ., 53-12-22, P.S. Bartholomew (9 CAS). Sierra Co.: Onion Cr., N. end Onion
Valley, 6075’, 64-10-21, Fl.B. Leech (1 CAS). Siskiyou Co.: Head of W. Branch Indian Cr., at Poker Flat, 5040’,
66-08-14, H.B. Leech (2 CAS). S. Fk. Sacramento River, 5200’, 53-07-08, H.P. Chandler (1 CAS). Headwaters E.
Fork of S. Fork Salmon River, Cecillville-Callahan road, 6000’, 68-07-31, H.B. Leech (10 CAS). Lower Boulder Lake,
Scott Mts., S. of Callahan, 6280’, 70-08-25, H.B. Leech (10 CAS). Upper Boulder Lake, Scott Mts. S. of Callahan,
6780’, 70-08-25, H.B. Leech (4 CAS). East Boulder Lake, Scott Mts. S. of Callahan, 6680’, 70-08-25, H.B. Leech (36
CAS). Blanche Lake, 4 mi. by road SE of Medicine Lake, ca. 6725’, 66-08-24, H.B. Leech (1 CAS). Medicine Lake,
sweep edge lagoon, 64-06-30, J. Schuh (1 JS). Stream flowing into Meeks Meadow Lake, 6.25 mi. airline SW Etna,
1925 m., 72-08-23, H.B. Leech (1 CAS). Tehama Co.: SW corner Tehama Co., 2 mi. SW of Government Camp, pool in
bed of dried up stream, grassy slope, 6000’, 60-07-29, H.B. Leech (30 CAS). Tulare Co.: Monache Mdws., 58-08-10, D.
Giuliani (2 CAS). Rt. 180 east of Gen. Grant Pk., 55-06-26, P.S. Bartholomew (1 CAS). Tuolumne Co.: Sonora Pass,
trib. Deadman Cr., 9500’, 62-08-09, H.B. Leech (6 CAS). Niagara Cr., Forest Campgrd., 6600’, 62-08-09, H.B. Leech
(1 CAS). Trinity Co.: Carrville, 47-08-21, no collr., (2 CAS). Unspecified Co.: No site, no date, no collr. (4 ASP; 2
MCZ). Colorado: Larimer Co.: North Park, 8000’, 33-08-18, E.B. Andrews (2 CAS). Summit Co.: Fremont Pass, 300’,
52-08-17, B. Malkin (4 CFMNH). Idaho: Bingham Co.: No site, no date, Hubbard & Schwarz (6 USNM). Blaine Co.:
Galena, 52-07-22, B. Malkin (1 UWA). Bonner Co.: Pack River, 50-07-19, H.B. Leech (1 CAS). Elmore Co.: Alturas
Lake, Sawtooth Mts., 52-07-22, B. Malkin (18 CFMNH; 20 UWA). Kootenai Co.: Athol, 53-05-12, W.F. Barr (1 UI; 1
UWA). Nevada: Lincoln Co.: Mormon, no date, Hubbard & Schwarz (1 CAS). Unspecified Co.: No site, no date, no
collr. (5 ASP). Oregon: Curry Co.: Pistol River, 52-06-18, B. Malkin (1 UWA). Harney Co.: Steens Mts., Fish Lake,
7580’, 51-06-22, B. Malkin (13 UWA). Lane Co.: McKenzie Pass, 30-06-21, M.H. Hatch (1 UWA). Washington:
Pacific Co.: Tokeland, 29-07-10, no collr. (2 UWA). Wyoming: Fremont Co.: 50 mi. SW Lander on Hiway 287, marg.
veg., 51-05-17, G.K. Todd (31 INHS). Sheridan Co.: 5 mi. NE of Granite Pass, roadside pool draining into Owen Cr.,
Big Horn Mts., 64-07-25, H.B. Leech (1 CAS). Uinta Co.: Trib. to Muddy Cr. at Hwy. 80, 8.3 mi. W. of Fort Bridger,
65-08-23, F.O. Leech (1 CAS).

10. Ochthebius kaszabi Janssens

Map: Figure 92A

Specimens examined: 286

Canada: Alberta: Edmonton, 19-04-26, F.S. Carr (1 CAS). Edmonton, 19-08-28, F.S. Carr (1 CAS). Edmonton,
17-09-15, F.S. Carr (2 CAS). Edmonton, 24-05-02, O. Bryant (1 CAS). 6 mi. S. Pincher Creek, 71-08-01, P.D. Perkins
(18 PDP). Cypress Hills Prov. Pk., 62-06-17, C.W. O’Brien (1 MCZ). Edmonton, 22-08-07, no collr. (4 OSU). Castor,
no date, no collr. (1 OSU). Bittern Lake, 61-08-15, A. & M. Brooks (3 CNC). British Columbia: Vernon, 37-09-18,
H.B. Leech (1 CAS). Vernon, 40-09-02, H.B. Leech (1 CAS). Armstrong, 45-06-01, H.B. Leech (2 CAS). Salmon
Arm, 29-08-26, H.B. Leech (2 CAS). Salmon Arm, 29-08-30, H.B. Leech (1 CAS). Salmon Arm, 37-09-06, H.B. Leech
(1 CAS). Salmon Arm, 39-07-02, H.B. Leech (7 CAS). Falkland, 32-09-16, E.B. Andrews (1 CAS). Lillooet Dist., 11
mi. S. Clinton, 71-07-23, P.D. Perkins (3 PDP). Kamloops, no date, Wickham (2 USNM). Cranbrook, 56-08-12, G.
Stace Smith (6 UBC). Copper Mtn., Similkameen River, 30-09-04, G. Stace Smith (13 UBC; 5 CNC). Copper Mtn.,
Similkameen River, 30-08-24, G. Stace Smith (6 UBC). Manitoba: The Pas, 30-05-28, O. Bryant (5 CAS). Treesbank,
4 mi. W. Hwy. 344, 68-08-14, R. Gordon (9 USNM). Winnipeg, 16-09-02, J.B. Wallis (1 CNC). Winnipeg, no date,
J.B. Wallis (1 CU). Winnipeg Beach, 10-07-11, J.B. Wallis (1 MCZ). Churchill, 37-08-10, W.J. Brown (17 CNC).
Treesbank, 10-07-25, J.B. Wallis (4 CNC). Winnipeg Beach, 10-08-23, J.B. Wallis (1 CNC). Aweme, 10-07-20, J.B.
Wallis (1 CNC). New Brunswick: French lake, 28-07-06, W.J. Brown (1 CNC). Northwest Territories: Ft. Simpson,
72-06-14, A. Smetana (34 CNC). Spence River, 38 mi. SE Ft. Simpson, 72-06-19, A. Smetana (1 CNC). Harris River,
Ft. Simpson, 72-06-15, A. Smetana (13 CNC). Rabbitskin R., 23 mi. SE Ft. Simpson, 72-06-12, A. Smetana (12
CNC). Ontario: Mer Bleue, 27-05-28, W.J. Brown (1 CNC). Ottawa, 30-05-15, W.J. Brown (4 CNC). Arnprior,
36-07-07, W.J. Brown (1 CNC). Quebec: Quarry Is., Mingan, 29-06-13, W.J. Brown (1 CAS;6 CNC). Pettit, no date,
Hubbard & Schwarz (3 USNM). Wakefield, 30-06-04, W.J. Brown (17 CNC). Pettit, no date, no collr. (1 MCZ).
Montreal, 69-06-25, E.J. Kiteley (1 EJK). Montreal, 69-08-05, E.J. Kiteley (1 EJK). Montreal, 69-09-07, E.J. Kiteley
(1 EJK). Fairy Lake, 30-05-13, W.J. Brown (1 CNC). Saskatchewan: Yorkton, 47-07-27, C.C. Shaw (2 CAS). Carlton,
48-09-11, J.R. Vockeroth (1 CNC).

United States: Alaska: Fairbanks, Farmers Loop, 57-08-11, E.L. Kessel (5 CAS). 100 mi. N. of Ft. Yukon,
27-05-12, J.M. Jessup (1 USNM). Ft. Yukon, no date, J.M. Jessup (19 UWA). Massachusetts: Barnstaple Co.:
Nonamasset Isd., 59-07-05, F.N. Young (7 PDP). Minnesota: Stearns Co.: St. Cloud, 10-01-66, no collr. (5 SC). St.
Cloud, 67-09-25, no collr. (4 SC). St. Cloud, 66-04-20, no collr. (1 SC). North Dakota: Bottineau Co.: No site,
62-07-15, R. Gordon (1 USNM). Lake Metigoshe, 63-05-23, R. Gordon (3 USNM). Cass Co.: Fargo, 66-07-07, R.
Gordon (1 RG). Divide Co.: No site, 63-05-23, R. Gordon (1 USNM). Nelson Co.: No site, 63-05-03, R. Gordon (1
USNM). Pierce Co.: No site, 63-05-14, R. Gordon (1 USNM). Richland Co.: No site, 64-08-19, R. Gordon (2 USNM).

Western Hemisphere Hydraenidae

513

T.135N R.52W, Sec.5, NW1/4, 68-08-22, no collr. (5 USNM). Mirror Pool, 65-08-20, R. Gordon (1 RG). Rolette Co.:
Dunseith, nr. jet. Hwy. 3 & 43, 68-08-18, R. Gordon (1 USNM; 5 RG). Sargent Co.: Tewaukon Ref. Headq. spring,
68-08-23, R. Gofgon (7 USNM).

1 1. Ochthebius rectus LeConte

Map: Figure 101 D

Specimens examined: 453

Canada: British Columbia: Royal Oak, V.I., 55-06-09, E. Argyle (1 UBC).

United States: Arizona: Cochise Co.: Huachuca Mts., Huachuca Canyon, 72-05-02, A.R. Gillogly (1 PDP).
California: Alameda Co.: No site, no date, A. Koebele (4 CAS). Contra Costa Co.: Berkeley, no date, F. Winters (1
CU; 4 CAS). Millbrae, 12-08-21, no collr. (1 CAS). No site, 38-05-01, F. Blum (1 OSU). Humboldt Co.: Areata, no
date, no collr. (1 CAS). Inyo Co.: Deep Springs, Deep Springs Valley, ca. 19 air mi. E. Bishop, 71-03-01, D. Giuliani (2
CAS). As above, 71-01-01 (2 CAS). As above, 71-02-01 (1 CAS). Saline Valley, Palm Spring, at edge of hot spring,
71-05-04, D. Giuliani (1 CAS). Deep Springs Valley, Buckhorn Springs, 72-01-22, D. Giuliani (2 CAS). As above,
71-04-22 (6 CAS). Saline Valley, Salt Lake, 71-09-21, D. Giuliani (4 CAS). Saline Valley, in small waterhole on
alkaline flat, 71-05-04, D. Giuliani (7 CAS). Little Black Rock Spring, 71-05-28, D. Giuliani (7 CAS). Lone Pine,
37-05-26, C.D. Michener (4 CNC; 1 CU; 26 CAS). Slough near Deep Springs Lk„ 4700’, 54-06-19, P. Raven (6 CAS).
Owens Lake, 72-03-01, D. Giuliani (6 CAS). Bad Water, Death Valley, 38-04-14, J. duBois (6 CAS). Cow Creek,
Death Valley, 64-06-04, E. Hilbert (56 CAS). Grimshaw Lake, freshwater, Tecopa, 1320’, 67-03-22, H.B. Leech (2
CAS). Pools, stream W. of Harmony Borax Works, Death Valley, -250’, 67-03-21, H.B. Leech (4 CAS). Furnace Creek
Ranch, 15 mi. N„ Death Valley, 31-06-08, J. Slevin (2 CAS). Death Valley, Salt Creek, 63-12-27, R. Bandar (2 CAS).
Panamint Valley, 91-04-01, A. Koebele (3 USNM). Shoshone, no date, no collr. (3 CAS). Death Valley, Badwater,
55-03-15, J. Schuh (1 JS). Bridgeport, 6465’, 33-07-15, Wickham (2 MCZ). Owens River, 7 mi. NW Bishop, 4400’,
70-11-30, P.D. Perkins (1 PDP). Kern Co.: Lebec, 45-06-28, G.P. Mackenzie (1 CAS). Los Angeles Co.: Los Angeles,
no date, F. Winters (2 CAS). Los Angeles, no date, Coquillett (2 USNM). Pomona, no date, W. Richardson (3
USNM). Redondo, no date, no collr. (2 CAS). Modoc Co.: Hot Springs, 5 mi. E. Cedarville, 60-06-05, J. Schuh (1 JS).
Mono Co.: Travertine Hot Sprgs., 2 mi. SE Bridgeport, 6700’. 62-08-11, H.B. Leech (1 CAS). Bridgeport, 6465’, no
date, Wickham (11 USNM). 6 mi. N. Bishop, Fish Slough, 70-04-20, P.D. Perkins (1 PDP). Orange Co.: Seal Beach,
salt marsh, 71-09-22, 1. Moore (10 UCR). Riverside Co.: Palm Springs, no date, F. Winters (1 CAS). Riverside, no
date, F. Winters (13 CAS). Riverside, no date, no collr. (2 USNM). Riverside, no date, H.C. Fall (11 MCZ). Fish
Springs, Salton Sea, 45-12-12, H. P. Chandler (1 CAS). Salton Sea, 16-04-16, J.O. Martin (1 CAS). Salton, no date,
Hubbard & Schwarz (5 USNM). San Jacinto Mts., no date, F.W. Winters (1 OSU). Sonorian Region, no date, F.E.
Winters (1 CU). San Benito Co.: Griswold Creek, Lyons Canyon on road to Idria, 63-07-21, H.B. Leech (9 CAS). San
Bernardino Co.: Death Valley NM. Saratoga Spring, 70-10-12, P.D. Perkins (6 PDP). San Diego Co.: Mountain Palm
Spr., Anza Desert, 65-04-14, no collr. (1 CAS). San Mateo Co.: SF Bay marsh E. Palo Alto, 63-01-01, P.S.
Bartholomew (4 CAS). Santa Barbara Co.: Santa Barbara, no date, F. Winters (9 CAS). Santa Clara Co.: Los Gatos,
no date, Hubbard & Schwarz (1 USNM). Unspecified Co.: No site, no date, no collr. (5 CFMNH; 2 ASP; 4 MCZ).
Idaho: Bear Lake Co.: N. shore of Bear Lake, 52-07-06, B. Malkin (1 UWA). Nevada: Elko Co.: Thousand Springs
creek, Route 30, 9 mi NE Montello, 69-08-26, H.B. Leech (12 CAS). Nye Co.: Ash Meadows, in swim pool, 66-03-30,
J. Schuh (4 JS). 2 mi. N. Beatty, saline pool, 66-03-29, J. Schuh (1 JS). Washoe Co.: 8 mi. S. Reno, alkaline irrigation
ditch, 74-04-28, A.R. Gillogly (37 PDP). Oregon: Harney Co.: Hot Springs, SE shore of Harney Lake, 51-06-20, B.
Malkin (19 CFMNH; 22 UWA). Malheur Lake, 51-06-20, B. Malkin (1 UWA). 1/2 mi. S. of Harney Lake, muck, hot
spring temp. 90 degrees F., 61-10-23, K. Goeden (1 UWA). 1/2 mi. S. Harney Lake, hot spring temp. 100 degrees F.,
62-08-09, K. Goeden (11 ODA). Trout Creek Hot Springs, 62-09-29, K. Goeden (6 ODA). Mickey Hot Spring,
62-09-26, K. Goeden (3 ODA). 9 mi. N. Andrews, margins of hot springs, 62-09-26, K. Goeden (3 ODA). Borax Hot
Lake, 62-09-27, K. Goeden (18 ODA). 20 mi. W. Malheur Lake, hot springs, 56-05-18, K. Goeden (13 ODA). 1/2 mi.
S. Harney Lake, hot spring, 63-06-04, K. Goeden (2 ODA). Klamath Co.: Bly, 45-06-13, K.M. Fender (1 UWA).
Upper Klamath Lake, along shoreline, 55-04-24, J. Schuh (1 JS). Mare’s Egg Spring, 59-09-07, J. Schuh (1 JS). Lake
Co.: Fresh pool, SE shore Lake Albert, 50-07-17, H.B. Leech (1 CAS). Malheur Co : 15 mi. NW Vale, hot springs,
temp, 108 degrees F., 62-09-09, K. Goeden (1 ODA). Utah: Unspecified Co.: Clear Lake, 33-07-02, Wickham (1
USNM). Washington: Pacific Co.: Nasel River, salt marsh, 30-08-06, no collr. (4 UWA). Bay Center, 31-03-26, no
collr. (4 UWA). Nahcotta, 55-08-18, no collr. (1 UWA). Tokeland, 29-07-10, no collr. (1 UWA). San Juan Co.: Lopez
Is., 26-07-03, no collr. (1 UWA). Wyoming: Albany Co.: Laramie, 94-03-13, no collr. (1 USNM). Unspecified Co.: No
site, no date, no collr. (1 ASP).

12. Ochthebius rectusalsus new species

Map: Figure 101 E

Quaest. Ent., 1980, 16 (1,2)

514

Perkins

Paratypes: 52

Mexico: Baja California: Norte, 3.2 mi. S. Colonia Guerrero, 63-04-24, H.B. Leech (1 CAS). La Salina, 4 mi. S. La
Mision de San Miguel, 61-05-21, I. Moore (1 CNC). Norte, Mision de San Miguel, on mud, salt flat, 59-06-21, I.
Moore ( 1 CAS).

United States: California: Contra Costa Co.: Same data as Holotype (16 CAS: 3 USNM; 2 PDP; 2 Ul). Los
Angeles Co.: Naples, 19-04-06, J.O. Martin (8 CAS). Pasadena, no date, no collr. (1 CAS). Redondo, no date, no collr.
(1 CAS). S. Cal., no date, no collr. (1 USNM). Marin Co.: Inverness, in salt marsh, 10-08-14, no collr. (1 CAS).
Merced Co.: Los Banos, 18-05-23, E.P. VanDuzee (1 CAS). Monterey Co.: Moss Landing, 09-01-22, no collr. (1 CAS).
San Diego Co.: San Diego, 92-02-24, Fall (3 MCZ). No site, no date, F.E. Blaisdell (1 CAS). San Mateo Co.: Millbrae,
in salt ponds, 12-07-21, no collr. (2 CAS). Santa Barbara Co.: Santa Barbara, no date, F. Winters (1 OSU). Ventura
Co.: Ojai Valley, no date, Hubbard & Schwarz (2 USNM). Washington: Clallam Co.: Sequim, 28-07-21, no collr. (1
UWA).

13. Ochthebius recticulus new species

Map: Figure 101 E
Paratypes: 143

United States: California: Colusa Co.: Same data as Holotype (20 USNM; 10 MCZ; 10 CNC; 60 PDP). Wilbur
Hot Springs, 74-06-26, W.N. Mathis (1 1 USNM; 6 ORSU). Tributary to Bear Creek, 9 mi. N. Wilbur Hot Springs, no
date, H.B. Leech (1 CAS). Sulphur Cr. at Wilbur Hot Sprs., 60-07-14, H.B. Leech (25 CAS).

14. Ochthebius bisinuatus new species

Map: Figure 101 F

Paratypes: 478

Canada: Alberta: Waterton River at Rt. 2, 15 mi. S. Macleod, 69-08-20, H.B. Leech (4 CAS). British Columbia:
Fernie, 35-08-12, H.B. Leech (2 CAS). Liliooet Dist., 11 mi. S. Clinton, 71-07-23, P.D. Perkins (36 PDP). Cariboo
Dist., 40 mi. NE McLeese Lake, 71-07-28, P.D. Perkins (15 PDP). Creston, Goat River, 45-09-23, G. Stace Smith (3
UBC). As above, 45-09-30 (1 UBC). As above, 46-08-25 (1 UBC). As above, 47-08-31 (1 UBC). Summerland,
32-05-28, A.N. Gartrell (1 CNC).

United States: California: Del Norte Co.: Smith River, 35-07-15, no collr. (1 UWA). Colusa Co.: Little Stony Cr., 6
mi. S. Stonyford, 56-03-29, H.B. Leech (5 CAS). Glenn Co.: N. fork Stony Cr., 0.5 mi. W. of Newville, 66-04-04, H.B.
Leech (1 CAS). Humboldt Co.: North Dobbyn Cr., Alderpoint-Blocksburg Rd., 68-07-19. H.B. Leech (1 CAS). No site,
11-05-03, Nunenmacher (1 CFMNH). South Eel River at Weott, 155’, 70-08-30, H.B. Leech (2 CAS). Lake Co.:
Middle Cr., Upper Lake, 49-05-28, H.B. Leech (11 CAS). Mendocino Co.: Black Butte River just above mouth,
68-07-17, H.B. Leech (1 CAS). Middle fork of Eel River, 0.3 mi. below mouth of Black Butte River, 1500’, 68-07-16,
H.B. Leech (10 CAS). Plumas Co.: Clio, on middle fork Feather River, 61-08-28, H.B. Leech (8 CAS). Mohawk,
57-07-09, D.C. Rentz (4 CAS). San Joaquin Co.: Manteca, 52-08-24, P.S. Bartholomew (2 CAS). Shasta Co.: Hat Cr.,
3000’, 47-06-28, H.P. Chandler (1 CAS). Sierra Co.: Onion Cr., N. end Onion Valley 6075’, 64-10-21, H.B. Leech (1
CAS). Siskiyou Co.: North fork Salmon River, 5 mi. NE of Forks of Salmon, 68-07-26, H.B. Leech (10 CAS). Scott
River, 1.5 mi. SE of Kelsey Cr., 66-08-17, H.B. Leech (1 CAS). Sonoma Co.: Cloverdale, 26-06-19, V.S. Brown (2
CAS). Tehama Co.: Red Bluff, 22-05-01, V.S. Brown (1 CAS). Trinity Co.: Mad River, 6 mi. S. Ruth, 60-07-31, H.B.
Leech (5 CAS). Trinity River at Big Flat, 60-08-04, H.B. Leech (14 CAS). Hayfork Cr., 0.5 mi. E. of Hyampon,
68-07-23, H.B. Leech (2 CAS). Mad River just above mouth Van Horn Cr., 4.25 air mi. SE of Ruth, pools in drying
bed of upper Mad River, 70-08-07, H.B. Leech (6 CAS). Idaho: Custer Co.: Salmon R., 14 mi. N. Challis, 71-08-03,
P.D. Perkins (3 PDP). Latah Co.: Boville, 32-06-18, M.H. Hatch (2 UWA). Lemhi Co.: Salmon R., 4 mi. N. Salmon,
71-08-03, P.D. Perkins (12 PDP). Twin Falls Co.: 11 mi. E. Rogerson, 52-07-20, B. Malkin (2 UWA). Magic Hot
Springs, 52-07-20, B. Malkin (22 UWA; 21 CFMNH). Montana: Blaine Co.: Bear Paw Mt., no date, Hubbard and
Schwarz (2 USNM). Ravalli Co.: Mill Cr. at Hwy. 93, 7 mi. N. Hamilton, 71-08-02, P.D. Perkins (23 PDP). Oregon:
Benton Co.: Monroe, 30-06-18, M.H. Hatch (1 UWA). Corvallis, pond, 56-04-08, K. Goeden (1 ODA). Harney Co.:
Blitzen River, 2 mi. E. Frenchglen, 4400’, 64-07-15, T. Schuh and J.D. Lattin (4 CAS; 6 JS; 9 ORSU). Klamath CO.:
Sprague River, 12 mi. E. Chiloquin, 51-07-03, B. Malkin (3 UWA). Sprague River, 12 mi. E. Chiloquin, 51-06-01, B.
Malkin (2 CFMNH). Sprague River nr. Bly, 52-06-22, B. Malkin (1 CFMNH). Lake Co.: Chandler State Park,
51-06-30, B. Malkin (3 UMA; 3 CFMNH). Linn Co.: Albany, 33-07-23, Wickham (1 USNM). Malheur Co.: Sucker
Creek Canyon, 51-06-18, B. Malkin (2 UWA; 4 CDMNH). Umatilla Co.: Echo, 32-08-31, M.H. Hatch (1 UWA).
Yamhill Co.: McMinnville, 42-07-05, K.M. Fender (4 UWA). Unspecified Co.: Medicine Lake, 36-07-04, no collr. (1
UWA). Washington: Benton Co.: Plymouth, 32-09-01, M.H. Hatch (1 UWA). Chelan Co.: Wenatchee, 32-08-23, M.H.
Hatch (6 UWA). Entiat, 32-08-23, M.H. Hatch (4 UWA). Clallam Co.: Pysht River, 32-05-30, no collr. (1 UWA).
Cowlitz Co.: Castle Rock, 32-07-10, no collr. (1 UWA). Jefferson Co.: Bogachiel River, 32-05-30, no collr. (1 UWA).

Western Hemisphere Hydraenidae

515

King Co.: N. Bend, 31-05-20, V. Tartar (3 UWA). Green River Gorge, 31-05-20, M.H. Hatch (2 UWA). Green River
Gorge, 56-07-15, Malkin and Kottke (4 CFMNH). Evans Creek, 29-07-04, M.H. Hatch (1 UWA). North Bend,
Maloney’s Grove, 46-05-23, M.H. Hatch (5 UWA). As above, 30-06-29, M.H. Hatch (12 UWA). As above, 30-05-10,
M.H. Hatch (38 UWA). Snoqualmie River, Maloney’s Grove, 27-09-05, M.H. Hatch (16 UWA). Renton, 13-05-31, no
collr. (22 UWA). Snoqualmie Falls, 30-05-10, M.H. Hatch (2 UWA). Kittitas Co.: Yakima River Canyon, 30-09-17,
M.H. Hatch (4 UWA). Ellensberg, 32-07-19, M.H. Hatch (10 UWA). Pacific Co.: Willapa River, 30-09-09, no collr. (1
UWA). Snohomish Co.: Arlington, 27-08-21, M.H. Hatch (4 UWA). Sultan, 30-05-02, M.H. Hatch (5 UWA). Sultan,
53-06-01, Malkin and Boddy (7 CFMNH). Stilaguamish River, 28-07-15, no collr. (6 UWA). N.F. Stilaguamish River,
Cicero, 27-08-21, M.H. Hatch (24 UWA). Spokane Co.: Spokane, no date, Wickham (1 USNM). Spokane, 32-08-26,
M.H. Hatch (3 UWA). Unspecified Co.: Iron Creek, 35-08-28, no collr. (2 UWA). S.F. Skokomish River, 56-07-15,
Malkin and Kottke (4 CFMNH). Neilson Lake, 30-05-23, M.H. Hatch (1 UWA). Wyoming: Natrona Co.: Badwater
Cr. at Badwater, NW of Arminto, 65-08-21, H.B. Leech (1 CAS).

15. Ochthebius californicus new species

Map: Figure 1 17B
ParatypeS:jJ 16

United States: California: Alameda Co.: Arroyo d. Valle, 72-03-06 W.H. Tyson (1 RG). Butte Co.: Little Chico
Creek, 70-11-26, P.D. Perkins (4 PDP). Fresno Co.: Fresno, no date, E.A. Schwarz (1 USNM). Inyo Co.: Tinemaha
Reservoir, 71-15-13, D. Giuliani (9 CAS). Lone Pine, 3500’, 13-06-15, R. Hopping (4 CAS). Lassen Co.: Eagle Lake,
21-07-31, J.O. Martin (10 CAS). Los Angeles Co.: Little Rock, Mojave Desert, no date, F.E. Winters (3 CAS). Tejon
Pass, 18-07-28, J.O. Martin (1 CAS). Pasadena, no date, no collr. (1 CAS). San Gabriel River, Rincon Sta., 1800',
71-04-17, P.D. Perkins (2 PDP). San Gabriel River, 4 mi. N. Azuza, 71-04-17, P.D. Perkins (3 PDP). Marin Co.:
Novato, collected at UV light, 62-09-08, D.C. Rentz (1 CAS). Monterey Co.: Little Sur R., vie. P. Ocean, 70-09-06,
P.D. Perkins (1 PDP). Nacimiento R., Ponderosa Public Camp, 70-09-06, P.D. Perkins (2 PDP). Hunter-Liggett M.R.,
Twin Valley and Coleman Reservoirs, 72-08-09, A.R. Gillogly (7 AG). Pleyto Rd. at San Antonio River, 68-04-09,
Rentz and Hale (1 CAS). Napa Co.: 5 mi. SE St. Helena, Conn Lake, 65-03-29, T. Schuh (1 JS). Riverside Co.:
Riverside, no date, F.E. Winters (1 CU; 16 CAS; 1 OSU). San Diego Co.: Camp Pendleton, 45-10-08, H.P. Chandler (2
CAS). Mission Vy., 33-08-19, I. Moore (1 CAS). Julian, 70-06-29, K. Stephan (1 KS). San Luis Obispo Co.: Lopez
Canyon Dam Outlet, 70-09-05, P.D. Perkins (2 PDP). Santa Barbara Co.: Santa Barbara, no date, F.E. Winters (1 CU;
6 CAS). Tulare Co.: Kern R., 9.5 road mi. N. Kernville, 70-03-25, H.B. Leech (14 CAS). Nevada: Ormsby Co.: Carson
City, 33-07-30, Wickham (7 USNM; 3 CAS; 2 UW; 3 MCZ). Carson, no date, F. Psota (4 CFMNH).

16. Ochthebius richmondi new species

Map: Figure 1 17B
Paratypes: 117

United States: California: Humboldt Co.: Same data as Holotype (7 CAS). Blue Lake, 07-06-20, Bradley (96 CU).
Washington: King Co.: North Bend, Maloney’s Grove, 31-05-16, M.H. Hatch (14 UWA).

17. Ochthebius costipennis Fall

Map: Figure 1 17A
Specimens examined: 1 1

United States: California: San Benito Co.: San Benito River, 55-06-18, P.S. Bartholomew (1 CAS; 1 PDP).
Pinnacles Nat. Mon., 1000’, 46-05-03, H.P. Chandler (1 CAS). Santa Barbara Co.: Santa Barbara, no date, F.E.
Winters (2 CAS; 1 CU; 1 MCZ). Lompoc, no date, F. Winters (1 PDP; 2 CAS). Clear Cr., Cuyama Cyn., 37-03-07,
H.B. Leech (1 CAS).

18. Ochthebius crenatus Hatch

Map: Figure 1 17A
Specimens examined: 19

United States: California: Willow Cr. just above its E. fork, 1500’, 70-08-29, H.B. Leech (1 CAS). Placer Co.: Lake
Tahoe, no date, Hubbard and Schwarz (1 CAS). Idaho: Latah Co.: Boville, 32-06-18, M.H. Hatch (2 UWA). Oregon:
Jackson Co.: Union Creek, 3100-3500’, 50-09-01, B. Malkin (1 CFMNH). Lake Co.: Crooked Cr., 19 mi. N. Lakeview,
55-06-07, J. Schuh (4 UWA; 8 JS). Lakeview, 52-06-22, B. Malkin (1 UWA). Unspecified Co.: Wilson River, coast

Quaest. Ent., 1980, 16 (1,2)

516

Perkins

range, 45-07-08, K.M. Fender (1 UWA).

20. Ochthebius attritus LeConte

Map: Figure 92A
Specimens examined: 635

Colombia: Atlantico: Barranquilla, 69-03-18, P. & P. Spangler (1 USNM). Magdalena: 8 km E. Barranquilla,
69-03-19, P. & P. Spangler (46 USNM). Isla Salmanca Parque Nat., 8 km W. Santa Marta, 68-02-27, B. Malkin (1
USNM).

Cuba: Oriente, Mayari Abajo, Loma la Bandera, 73-03-29, V. Decu (1 USNM).

Dominican Republic: Barahona, 38-09-15, Darlington (27 MCZ).

Mexico: Yucatan: Progresso, beneath debris on seashore, 71-05-07, E. Anderson (1 CAS).

Puerto Rico: Playa Salina nr. Corozo, in salt water, 61-08-13, Flint & Spangler (480 USNM).

United States: Florida: Brevard Co.: Titusville, no date, no collr. (1 CAS; 1 CNC). Lee Co.: Koreshan St. Pk., 19
mi. S. Ft. Myers, B.L. Trap, 68-06-08, F.E. Wood (5 USNM). Monroe Co.: Everglades Natl. Park, 5 mi. N. Flamingo,
Snake Bight Trail, sawgrass-mangrove area, 65-08-27, W. Suter (2 PDP). Big Pine Key, 77-01-06, W.E. Steiner (57
USNM). Okeechobee Co.: Mouth of Kissimmee River, 39-04-06, J.C. Bradley (1 CU). Texas: Cameron Co.:
Brownsville, 04-06-03, FLS. Barber (10 USNM). Brownsville, Esprza Ranch, no date, no Collr. (1 CU).

21. Ochthebius batesoni Blair

Map: Figure 180
Specimens examined: 52

Ecuador: Galapagos Islands: James Bay, Espumilla Beach, Lagoon, 73-07-01, F.N. Young (30 USNM; 10 FNY; 10
PDP). Flamingo intestine. Flamingo collected on Isabel Island, Poza del Cementario Lagoon, 76-1 1-06, R.W. Tindle (2
USNM).

22. Ochthebius sculptoides new species

Map: Figure 123B

Paratypes: 242

Mexico: Aguascalientes: Aguascalientes, 63-08-05, P.J. Spangler (16 USNM). Durango: San Juan del Rio,
64-06-27, P.J. Spangler (1 USNM). Morcillo, 64-06-28, P.J. Spangler (1 USNM). San Luis Potosi: Rio Borgues,
stream, 57-06-19, D. Lauck (2 USNM). Sinaloa: Culiacan, 29 mi. S., 63-06-23, J. Doyen (1 UCB). Zacatecas: 29 mi.
NW Zacatecas, stream in desert, 74-07-16, M.E. & P.D. Perkins (12 PDP).

United States: Arizona: Cochise Co.: Wood Cn„ Bisbee, UV light, 61-07-03, P.H. Johnson (2 UA). Yavapai Co.:
Bumble Bee, 19-05-20, E. Schiffel (1 CAS). Unspecified Co.: No site, no date, no collr. (6 ASP). California: Colusa
Co.: Little Stony Cr. at Lodoga-Stonyford Rd., 71-04-07, H.B. Leech (1 CAS). Little Stony Cr., 6 mi. S. Stonyford,
56-03-29, H.B. Leech (5 CAS). Fresno Co.: Waltham Cr. by Rt. 198, 515 road mi. SW of Coalinga, 70-03-27, H.B.
Leech (1 CAS). Glenn Co.: Salt Cr. at Stony Cr. N. of Stonyford, 56-03-29, H.B. Leech (2 CAS). Trib. to Stony Cr., 7
mi. N. Stonyford, 56-03-29, H.B. Leech (1 CAS). Inyo Co.: Shoshone, no date, no collr. (2 CAS). Monterey Co.: Lewis
Cr., 52-08-29, H.B. Leech (2 CAS). Bryson, 63-04-09, Rentz and Hale (1 UCB). Napa Co.: Pope Cr. at Walter Springs
Rd., 520’, 64-08-31, H.B. Leech (2 CAS). San Benito Co.: Pinnacles Natl. Monument, 1000’, 46-03-05, H. Chandler (1
CAS). Clear Cr., 10 mi. WSW New Idria mine, 69-08-15, V. Lee and S.C. Williams (1 CAS). Santa Barbara Co.:
Santa Barbara, no date, F. Winters (3 CAS; 1 OSU). Santa Inez Mts., no date, F. Winters (3 OSU). Siskiyou Co.:
Sugar Cr., 2.3 mi. NW of Callahan, 66-08-17, H.B. Leech (2 CAS). Stanislaus Co.: Del Puerto Cr., 4 mi. by road W. of
Freewy Rt. No. 5, 71-09-03, H.B. Leech (2 CAS). Unspecified Co.: No site, no date, no collr. (1 ASP). Colorado: Rout
Co.: Yampa River, 14 mi. E. Craig, Hwy 40, 6400’, 67-07-13, H.B. Leech (12 CAS). Idaho: Twin Falls Co.: Magic Hot
Springs, 52-07-20, B. Malkin (1 CFMNH; 1 UWA). Montana: Blaine Co.: Bear Paw Mt., no date, Hubbard and
Schwarz (6 CAS). Madison Co.: Ziegler Hot Springs, 52-07-27, B. Malkin (56 CFMNH). Nevada: Lincoln Co.:
Cathedral Gorge St. Park, 71-07-12, J. Doyen (1 UCB). Oregon: Crook Co.: Prineville, river in gravel but much
algaceous slime, 50-07-29, B. Malkin (6 UWA). Douglas Co.: Glendale, 38-06-14, M.H. Hatch (1 UWA). Jackson Co.:
Medford, 33-07-24, Wickham (5 CAS; 1 USNM; 3 UW). Medford, no date, Wickham (6 MCZ). Josephine Co.: Cave
Junction, 47-05-17, B. Malkin (1 UWA). Grave Creek, 52-05-30, B. Malkin (2 UWA). Malheur Co.: Sucker Creek
Canyon, 51-06-15, B. Malkin (28 CFMNH; 31 UWA). Utah: Weber Co.: Ogden, no date, Hubbard and Schwarz (2
CAS). Wyoming: Natrona Co.: Badwater Cr. at Badwater, NW of Arminto, 65-08-21, H.B. Leech (3 CAS). Fremont
Co.: Burris, 10 mi. NW E. Fork Wind River, 62-08-23, H.B. Leech (5 CAS).

Western Hemisphere Hydraenidae

517

23. Ochthebius sculptus LeConte

Map: Figure 123A
Specimens examined: 147

Mexico: Baja California: Arroyo de la Purisima, 1 mi. upstream from town, 58-12-27, H.B. Leech (14 CAS). No
site, no date, no collr., (1 CNC).

United States: California: Del Norte Co.: Smith River, 35-07-15, no collr. (15 UWA). Humboldt Co.: Willow Cr.
16-06-12, F.E. Blaisdell (3 CAS). N. fork Mattole River, NW of Petrolia, 65-10-02, H.B. Leech (11 CAS). Blue Lake,
07-06-20, Bradley (1 CU). Los Angeles Co.: Elizabeth Lake, 16-05-11, J.O. Martin (15 CAS). Riverside Co.: San
Jacinto Mts., no date, F.E. Winters (1 CAS). San Bernardino Co.: Mojave River near Victorville, 56-02-12, R.K.
Benjamin (58 CAS). Hesperia, 18-06-30, J.O. Martin (12 CAS). Sonoma Co.: 5.5 mi. E. of Guerneville, no date, P.
Rubtzoff (3 CAS). Trinity Co.: Mad river, 6 mi. S. Ruth, 60-07-31, H.B. Leech (2 CAS). South Fork Trinity River,
Salmon Rock Camp, Hyampon-Big Slide road, 68-07-23, H.B. Leech (4 CAS). Oregon: Curry Co.: Pistol River,
50-09-18, B. Malkin (6 UWA). Douglas Co.: S. Umpqua River at Canyonville, 71-07-17, P.D. Perkins (1 PDP).

24. Ochthebius tubus new species

Map: Figure 135B
Paratypes: 282

Mexico: Baja California: Arroyo de la Purisima, 1 mi. upstream from town, 58-12-27, H.B. Leech (2 CAS). 3.2 mi.
S. Colonia Guerrero, 63-04-24, H.B. Leech (2 CAS). La Suerte, Sierra San Pedro Martir, pool in canyon, 3700',
63-06-04, R.K. Benjamin (11 CAS). 8 mi. upstream from Hamilton Ranch, dam site, 63-04-23, H.B. Leech (2 CAS).
San Luis Potosi: 2 mi. S. San Luis Potosi, 48-1 1-21, H.B. Leech (2 CAS). Rio Borques, stream, 57-06-19, D. Lauch (3
USNM). Tamaulipas: Nr. San Antonio, 69-07-27, F.N. Young (6 USNM).

United States: Arizona: Gila Co.: 26 mi. N. Roosevelt, Tonto Creek, 66-04-06, J. Schuh (1 JS). Mojave Co.: Peach
Springs, no date, no collr. (1 CAS). California: Alameda Co.: Arroyo d. Valle, 72-03-06, W.J. Tyson (8 RG). Humboldt
Co.: South Eel River at Weott, 155’, 70-08-30, H.B. Leech (1 CAS). Lake Co.; Hidden Lake, 4 mi. NW Lakeport,
55-08-05, H.B. Leech (1 CAS). Los Angeles Co.: San Gabriel River, Rincon Station, 1800’, 70-08-29, P.D. Perkins (9
PDP). San Gabriel River, Rincon Station, 1800’, 71-04-17, P.D. Perkins (12 PDP). San Gabriel River, Cogswell Res.,
2400’, 71-03-28, P.D Perkins (15 PDP). San Gabriel River, 4 mi. N. Azuza, 71-04-17, P.D. Perkins (12 PDP).
Pasadena, no date, F.E. Winters (1 CAS). Palmdale, 18-06-09, J.O. Martin (12 CAS). San Dimas, 49-01-01, K.R.
Hobbs (6 ORSU). Mendocino Co.: No site, 18-1 1-03, E.R. Leach (4 CAS). Monterey Co.: Carmel River, 50-08-20, P.S.
Bartholomew (14 CAS). Carmel, 31-07-18, no collr. (1 CAS). Nacimiento R., Ponderosa Public Camp, 70-09-06, P.D.
Perkins (3 PDP). Hunter Ligget, Nacimiento R., 73-05-25, A.R. Gillogly (3 AG). Bryson, 63-04-09, Rentz & Hale (1
MCZ). Napa Co.: Pope Cr. at Walter Springs Rd., 520’, 64-08-24, H.B. Leech (15 CAS). Orange Co.: Upper Trabuco
Cyn., 70-02-18, P.D. Perkins (1 PDP). Riverside Co.: San Jacinto Mts., no date, F.E. Winters (1 CAS). San Diego Co.:
Camp Pendleton, Oceanside, 45-10-18, H.P. Chandler (4 CAS). San Diego, no date, F.E. Blaisdell (24 CAS). Dulzura
Cr., 1 mi. S. Dulzura, 7007-20, P.D. Perkins (1 PDP). San Joaquin Co.: Manteca, 52-08-24, P.S. Bartholomew (1
CAS). San Luis Obispo Co.: Lopez Canyon Dam outlet, 70-09-05, P.D. Perkins (4 PDP). Santa Barbara Co.: Santa
Barbara, Santa Inez Mts., no date, F.E. Winters (18 CAS; 1 CU). Tulare Co.: 2 mi. N. Kennedy Mdws., 70-05-09, P.D.
Perkins (45 PDP). 3 mi. NW Kennedy Mdws., Fish Cr., 70-05-10, P.D. Perkins (2 PDP). Yolo Co.: Winters, 46-08-22,
H.P. Chandler (1 CAS). Montana: Blaine Co.: Bear Paw Mt., no date, Hubbard & Schwarz (2 USNM). Oklahoma:
Woods Co.: 3 mi. W. Waynoka, old road to Herman, at light 67-08-11, H.B. Leech (1 CAS). Texas: Uvalde Co.:
Uvalde, 930’, 33-06-20, Wickham (1 USNM). Val Verde Co.: Del Rio, 955’, 33-06-27, Wickham (19 USNM; 6 MCZ).
Wyoming: Crook Co.: Devil’s Tower Nat’l. Mon., Belle Fourche River, 62-08-13, P.J. Spangler (2 USNM).

25. Ochthebius alpinopetrus new species

Map: Figure 99B
Paratypes: 14

United States: Colorado: Fremont Co.: Canon City, no date, Wickham (1 ASP). Wyoming: Natrona Co.: Same data
as Holotype (5 CAS; 2 USNM; 1 CNC; 2 PDP). Park Co.: Meeteetse, 52-08-03, B. Malkin (3 CFMNH).

26. Ochthebius spanglerorum Wood and Perkins

Map: Figure 99B
Specimens examined: 135

Quaest. Ent., 1980, 16 (1,2)

518

Perkins

United States: Colorado: Fremont Co.: Canon City, no date, Wickham (1 CAS). Montezuma Co.: Navajo Spring
Creek, 72-08-04, P.D. Perkins (11 USNM). New Mexico: Lincoln Co.; 5 mi. N. Angus, Hwy. 37, 7050’, 65-08-07, H.B.
Leech (31 CAS; 4 USNM). Torrance Co.: 10 mi. SW Mountainair, stream by Abo State Mon., 67-08-21, H.B. Leech
(7 CAS). North Dakota: Williams Co.: Williston, no date, Wickham (1 CAS). Utah: Emery Co.: San Rafael Swell,
5000’, 40-1 1-05, H.P. Chandler (3 CAS). Washington Co.: St. George, no date, Wickham (4 CAS; 5 USNM; 4 MCZ).
Leeds, 33-08-07, Wickham (22 USNM; 4 CAS; 6 MCZ). Wayne Co.: 14 mi. S. Hanksville, light, sand-oak area,
68-08-03, H. & A. Howden (5 CNC). Wyoming: Bighorn Co.: Mouth of Shell Cyn. at Shell, 4230’, 64-07-25, H.B.
Leech (1 CAS). Carbon Co.: Medicine Bow, 41-08-22, H.P. Chandler (2 CAS). Johnson Co.: S. fork of Crazy Woman
Cr„ 64-07-27, H.B. Leech (1 CAS). Natrona Co.: Dugout Cr., 8.5 mi. NW of Midwest, 64-07-27, H.B. Leech (19
CAS). Sweetwater Co.: 10 mi. W. Rock Springs, Hwy. 30, Ox-bow cut-off of Bitter Cr., 65-08-23, H.B. Leech (4 CAS).

27. Ochthebius aztecus Sharp

Map: Figure 121
Specimens examined: 524

Mexico: Distrito Federal: Mexico City, 59-07-30 Drake & Hotles (1 USNM). Durango: Morcillo, 64-06-28, P.J.
Spangler (2 USNM). Mexico: Chapingo, en arena de rio, 59-02-01, I. Martell (10 USNM). Puebla: Lag. Totolzingo,
Rt. 136, km 200, 66-08-02, Flint & Ortiz (1 USNM). Lago Alchichica, 48-12-19, H.B. Leech (1 CAS).

United States: Arizona: Cochise Co.: Wilcox Playa, 69-11-02, K. Stephan (7 KS). Wilcox, 68-04-28, K. Stephan (2
KS). California: Inyo Co.: Tecopa, freshwater S. Francis (near Grimshaw) Lake, 64-03-24, H.B. Leech (1 CAS).
Drainage of Carson Slough, Amargosa Desert, 2.3 mi. NE Death V. Junction, 2045’, 67-03-22, H.B. Leech (60 CAS).
Pool in dry bed of Amargosa River, 7.8 mi. S. of Death Valley Junction, 67-03-22, H.B. Leech (3 CAS). Deep Springs,
Deep Springs Valley, ca. 19 air mi. E. Bishop, 71-02-01, D. Giuliani (16 CAS). Deep Springs Valley, Buckhorn Springs,
71-04-22, D. Giuliani (3 CAS). Tecopa, 71-12-26, D. Giuliani (20 CAS). Los Angeles Co.: E. fork San Gabriel River,
San Gabriel Mts., 69-04-25, P.D. Perkins (1 PDP). Mono Co.: Travertine Hot Spgs., 2 mi. SE Bridgeport, 63-08-15,
H.B. Leech (81 CAS). Bridgeport, no date, Wickham (1 CAS). Bridgeport, 6465’, 15-06-12, Wickham (2 MCZ; 24
USNM). San Bernardino Co.: Death Valley NM, Saratoga Spring, 70-10-12, P.D. Perkins (5 PDP). Siskiyou Co.:
Macdoel, 67-06-12, J. Schuh (1 JS). Indian Tom Lake, 55-05-30, J. Schuh (202 JS). As above, 67-05-03, J. Schuh (7
JS). As above, 66-09-27, J. Schuh (1 JS). Nevada: Eureka Co.: Beowawe, hot spring No. 24, 38-08-01, no collr. (2
USNM; 7 MCZ; 2 CAS). Nye Co.: Clay Camp, Ash Meadows, 64-03-25, H.B. Leech (1 CAS). Ash Meadows,
70-10-10, P.D. Perkins (1 PDP). New Mexico: Bernalillo Co.: Albuquerque, no date, no collr. (1 CDMNH; 1 CNC; 1
SDSU; 2 CAS). Albuquerque, no date, Wickham (1 UW; 2 USNM). Unspecified Co.: No site, no date, no collr. (2
MCZ; 3 CFMNH). North Dakota: Bottineau Co.: Lake Metigoshe, 63-05-23, R. Gordon (1 USNM). Slope Co.: No
site, 62-09-13, R. Gordon & R.L. Post (1 USNM). Oregon: Harney Co.: Hot Spgs., SE shore of Harney Lake,
51-06-20, B. Malkin (1 UWA). 20 mi. E. Fields, creek 59-06-24, K. Goeden (1 UWA). Klamath Co.: Lower Klamath
Lake, 55-05-30, T. Schuh (3 UWA). Lower Klamath Lake, in alkaline lake, 55-05-30, J. Schuh (3 UWA). Lower
Klamath Lake, alkali lake, 58-06-21, J. Schuh (1 JS). As above, 55-05-30 (8 JS). Lake Co.: Abert Lake, 57-04-28, J.
Schuh (3 JS; 1 UWA). Lakeview, 51-08-28, B. Malkin (2 UWA). Utah: Salt Lake Co.: Saltair, 4000’, 41-07-15, H.P.
Chandler (18 CAS). Salt Lake, no date, H.S. Barber (1 USNM). Salt Lake, no date, Hubbard & Schwarz (1 USNM).
Weber Co.: No site, 57-07-16, G.F. Knowlton (1 OSU).

28. Ochthebius biincisus new species

Map: Figure 127B
Paratypes: 32

United States: California: Alameda Co.: Arroyo d. Valle, 72-03-06, B. Malkin (1 CFMNH). Del Norte Co.: No site,
10-06-01, Nunenmacher (3 CFMNH). Humboldt Co.: Korbel, 16-06-18, F.E. Blaisdell (3 CAS; 1 CFMNH).
Pepperwood, Eel River, 38-05-16, H.B. Leech (2 CAS). Marin Co.: Lake Lagunitas, 19-09-01, J.O. Martin (1 CAS).
Mendocino Co.: Pieta Cr. at Route 101, Pieta, 465’, 70-08-31, H.B. Leech (1 CAS). Eel River R.S., 7 mi. W., 1450’,
72-06-10, S.L. Szerlip (2 UCB). Monterey Co.: Little Sur R., vie. Pacific Ocean, 70-09-06, P.D. Perkins (15 PDP).
Siskiyou Co.: North Fork Salmon River, 5 mi. NE forks of Salmon, 68-07-26, H.B. Leech (2 CASj. Oregon: Curry Co.:
Pistol River, 56-09-17, B. Malkin (1 CFMNH).

29. Ochthebius gruwelli new species

Map: Figure 127B
Paratypes: 27

Mexico: Baja California: Sierra San Pedro Martir, La Grulla, 6900’, 53-06-12, P.H. Arnaud, Jr. (2 CAS). Norte,

Western Hemisphere Hydraenidae

519

Sa. Juarez, 1 mi. S. Laguna Hanson, 5000’, 70-07-19, P.D. Perkins (1 PDP). Norte, Sa. Juarez, 20 mi. N. El Rodeo,
70-03-26, J.A. Gruwell & P.D. Perkins (1 PDP). Norte, San Pedro Martir, Cyn. Diablito, 70-03-27, J.A. Gruwell &
P.D. Perkins (1 PDP).

United States: California: Los Angeles Co.: Pasadena, no date, F. Winters (1 PDP). Wickiup Public Camp,
70-08-01, P.D. Perkins (2 PDP). San Gabriel River, E. Fork, Mine Gulch Public Camp, 4500’, 70-07-26, P.D. Perkins
(4 PDP). San Gabriel River, W. Fork Sta., 3100’, 70-08-01, P.D. Perkins (2 PDP). As above, 71-11-01 (4 PDP). San
Gabriel River, N. Fork, Coldbrook Sta., 3600’, 71-02-27, P.D. Perkins (3 PDP). Riverside Co.: San Jacinto Mts., no
date, F. Winters (1 CAS). Palm Canyon, 16-04-15, J.O. Martin (2 CAS; 2 PDP). Ventura Co.: Sespe Cr., Sespe Gorge,
3500’, 72-06-18, P.D. Perkins (1 PDP).

30. Ochthebius arizonicus new species

Map: Figure 127B
Paratypes: 17

United States: Cochise Co.: Huachuca Mts., 37-1 1-03, O. Bryant (1 CAS). Gila Co.: 19 mi. N. Roosevelt, Sycamore
Cyn., 66-04-06, J. Schuh (2 JS; 2 CAS; 4 PDP). 26 mi. N. Roosevelt, Tonto Cr., 66-05-06, J. Schuh (1 PDP). Pinal
Co.: Tortolita Mts., Cottonwood Cyn., 69-12-14, K. Stephan (2 KS; 4 PDP). Yavapai Co.: Bumble Bee, 19-05-20, E.
Schiffel (1 CAS).

31. Ochthebius madrensis new species

Map: Figure 127A
Paratypes: 1 1

Mexico: Durango: 9 mi. E. Los Bancos, ca 90 mi. W. Durango, stream, pine forest meadow, 74-07-17, M.E. & P.D.
Perkins (3 PDP).

United States: Arizona: Cochise Co.: Portal, Southwest Research Station, 76-05-14, W.E. Steiner (5 USNM). W.
Turkey Cr. Camp, Chiricahua Mts., UV lite, 5900’, 64-06-15, J. Burger (1 UA). Santa Cruz Co.: Santa Rita Mts.,
Madera Cyn., 68-06-22, K. Stephan (1 KS). Pajarito Mts., Sycamore Cyn., 68-08-24, K. Stephan (1 KS).

33. Ochthebius mexcavatus new species

Map: Figure 127A
Paratypes: 135

Mexico: Durango: Same data as Holotype (5 CAS; 30 USNM; 5 CNC; 5 MCZ; 80 PDP). 1 mi. E. Los Bancos, ca
98 mi. W. Durango, stream in pine forest, 74-07-17, M.E. & P.D. Perkins (2 PDP). 9 mi. E. Los Bancos, ca 90 mi. W.
Durango, stream, pine forest meadow, 74-07-17, M.E. & P.D. Perkins (5 PDP). Sinaloa: 1 mi. W. El Palmito, stream in
pine forest, 74-07-19, M.E. & P.D. Perkins (2 PDP). Sonora: 7 mi. SE Alamos, 71-1 1-27, K. Stephan (1 KS).

34. Ochthebius obscurus Sharp

Map: Figure 130
Specimens examined: 6

Mexico: Guanajuato: Guanajuato (two female syntypes, one each in BMNH and USNM). Hidalgo: 2 mi. N.
Zimapan, intermittent desert stream, 74-05-21, M.E. and P.D. Perkins (2 females PDP). Mexico: 11 mi. S. Valle de
Bravo, stream in deciduous-pine forest, 74-07-12, M.E. and P.D. Perkins (1 male, 1 female PDP).

35. Ochthebius mesoamericanus new species

Map: Figure 130
Paratypes: 85

Guatemala: Baja Verapaz: 10 mi. S. Rabinal, 74-06-12, ME & PD Perkins (2 PDP). Huehuetenango: 35 mi. S. La
Mesilla, tropical brook, 74-05-31, ME & PD Perkins (3 PDP). Jalapa: 45 mi. E. Jalapa, small pool at base of waterfall,
74-06-14, ME & PD Perkins (3 PDP). Totonicapan: 25 mi. S. Huehuetenango, small, rapid stream, 74-06-01, ME &
PD Perkins (3 PDP).

Mexico: Chiapas: 27 mi. N. Comitan, somewhat muddy stream, 74-07-01, ME & PD Perkins (6 USNM: 6 PDP).
Durango: 9 mi. E. Los Bancos, ca 90 mi. W. Durango, stream, pine forest meadow, 74-07-17, ME & PD Perkins (20

Quaest. Ent., 1980, 16 (1,2)

520

Perkins

USNM: 30 PDP). 10 mi. W. El Salto, 64-06-10, E.E. Lindquist (1 CNC). Jalisco: 7 mi. S. Mazamitla, stream in pine
forest, 74-07-15, ME & PD Perkins (1 PDP). San Luis Potosi: Quinta Chilla near Tamazunchale, 48-12-21, H.B. Leech
(8 CAS). Sinaloa: 1 mi. W. El Palmito, stream in pine forest, 74-07-19, ME & PD Perkins (1 PDP). Sonora: 7 mi. SE
Alamos, 71-1 1-27, K. Stephan (1 KS).

36. Ochthebius benefossus LeConte

Map: Figure 99C
Specimens examined: 39

Canada: Ontario: Dundas, 31-05-31, W.J. Brown (5 CNC). Walsh, 31-06-10, W.J. Brown (7 CNC). Quebec:
Knowlton, 28-06-19, G.H. Fisk (1 CNC).

United States: Indiana: Lawrence Co.: No site, 10-07-16, W.S. Blatchley (2 USNM). Maryland: Harford Co.:
Rocks, 60-09-02, P.J. Spangler (10 USNM). Garrett Co.: Deep Creek Lake, 65-06.-13, R. Gordon (1 RG). New Jersey:
Unspecified Co.: No site, no date, no collr. (2 ASP). Pennsylvania: Westmoreland Co.: St. Vincent, no date, no collr. (2
USNM). Vermont: Bennington Co.: No site, no date, no collr. (2 ASP). Virginia: Fairfax Co.: Dead Run, in wet
Hypnum moss, 14-1 1-14, R.C. Shannon (7 USNM).

37. Ochthebius discretus LeConte

Map: Figure 135A
Specimens examined: 922

Canada: British Columbia: Metlakatla, no date, no collr. (3 CAS). Victoria, Van. Id., no date, Hubbard & Schwarz
(2 CAS; 1 ASP; 2 USNM).

Mexico: Baja California: La Suerte, Sierra San Pedro Martir, 3700’, pool in canyon, 63-06-04, R.K. Benjamin (1
CAS).

United States: California: Alameda Co.: Arroyo d. Valle, 72-03-06, W.H. Tyson (8 RG). Berkeley, no date, F.E.
Winters (1 CAS). No site, 06-06-01, Nunenmacher (3 CFMNH). Calaveras Co.: Mokelumne Hill, no date, F.E.
Blaisdell (1 CAS). Calaveras Big Trees, 37-09-13, F.E. Blaisdell (12 CAS). Colusa Co.: Paradise Cr„ 2400’, 53-10-14,
H.P. Chandler (1 CAS). Contra Costa Co.: Bryant, 35-08-04, I. Moore (1 CAS). Hills back of Oakland, 11-05-14, no
collr. (8 CAS). Danville, 51-06-01, F.X. Williams (10 CAS). Perkins Gulch, 7 mi. SE Clayton, 66-07-22, J. Doyen & P.
Opler (1 UCB). S.F. Bay area, no date, D. Giuliani (1 CAS). Mt. Diablo, 19-09-21, J.O. Martin (5 CAS). Del Norte
Co.: No site, 10-06-10, Nunenmacher (5 CFMNH). El Dorado Co.: Riverton, 72-06-15, no collr. (1 CAS). Fresno Co.:
Bass Lake, 34-04-01, no collr. (1 CAS). Glenn Co.: N. Fork Stony Creek, 0.5 mi. W. of Newville, 66-04-04, H.B. Leech
(1 CAS). NW corner Glenn Co., 6500’, 4.5 mi S. of Mendocino Pass, 60-07-29, H.B. Leech (6 CAS). Black Butte,
6500-7400’, 72-06-16, J. Doyen (2 UCB). Humboldt Co.: Hydesville, 01-06-01, no collr. (4 CAS). Areata, 01-07-01, no
collr. (1 CAS). No site, no date, no collr. (4 CAS). Roaring Gulch Cr., Redwood Valley, ca 5 mi. N. Hoopa Rd.,
70-08-14, H.B. Leech (1 CAS). Toss-up Creek, confluence with Redwood Cr., 2.5 mi. N. of road to Hoopa, 650’,
70-08-13, H.B. Leech (1 CAS). Willow Creek just above its E. Fork, 1500’, 70-08-29, H.B. Leech (4 CAS).
Pepperwood, Eel River, 38-05-16, H.B. Leech (1 CNC; 1 CU; 6 CAS). Van Duzen River, 8.8 mi. W. Bridgeville,
66-08-07, H.B. Leech (1 CAS). Mill Cr., 7.5 mi. S. of Bridgeville, 1200’, 68-07-19, H.B. Leech (11 CAS). South
Dobbyn Creek, Alderpoint-Blocksburg road, 450’, margin of Typha pool, 68-07-19, H.B. Leech (1 CAS). Willow Creek,
16-06-12, F.E. Blaisdell (10 CAS). Korbel, 16-06-17, F.E. Blaisdell (2 CAS). Lake Co.: Creek behind Cottage City
Resort, Lucerne, 53-07-05, H.B. Leech (2 CAS). 0.6 mi. SE of Glenbrook, pool in dry stream bed, trib. of Kelsey Cr.,
66-05-30, H.B. Leech (4 CAS). Rice Fork of Eel River at Crabtree Hot Springs, 57-08-09, H.B. Leech (1 CAS). L.
Blue Lake, 1500’, 47-11-08, H.P. Chandler (1 CAS). Lassen Co.: Norval Flats, 5500’, 20-07-25, J.O. Martin (1 CAS).
Manzanita Lake, 41-06-17, C. Michener (2 CAS). Los Angeles Co.: Los Angeles, collected from moss bedding (Lilac),
32-10-17, no collr, (1 CAS). Los Angeles, no date, no collr. (2 CAS). No site, no date, no collr. (2 CAS). Madera Co.:
Sugar Pine, no date, A. Fenyes (1 CAS). Marin Co.: Mill Valley, Cascade Creek, 51-05-09, R.E. Leech (22 CAS).
Olema, 48-03-01, H.P. Chandler (1 CAS). Bolinas, 06-09-10, no collr. (7 CAS). Mill Valley, 04-06-15, no collr. (1
CAS). Lagunitas Cyn., 19-11-08, J.O. Martin (2 CAS). Lagunitas, 22-09-01, F.E. Blaisdell (4 CAS). Fairfax, no date,
F.E. Blaisdell (1 CAS). Inverness, stream, 51-05-16, H.B. Leech (30 CAS). Lagunitas, 08-06-14, no collr. (3 CAS).
Muir Woods, 08-08-30, no collr. (1 CAS). 10 mi. E. Marshall, Marshall-Petaluma Rd., roadside marsh, 64-02-22, H.B.
Leech (1 CAS). Lagunitas Lake, 2000’, 46-08-14, H.P. Chandler (1 CAS). Cataract Creek, Rock Spring, Mt.
Tamalpais, 52-05-25, H.B. Leech (18 CAS). Novato, stream bed by sifting, 52-06-17, H.B. Leech (4 CAS). San Rafael,
50-06-25, P.S. Bartholomew (5 CAS). Pool at culvert, Tocaloma, 68-05-04, H.B. Leech (5 CAS). Lagunitas Creek at
Tocaloma, 68-05-04, H.B. Leech (36 CAS). Marshall, stream, N. end of town at Highway No. 1, 63-10-20, H.B. Leech
(1 CAS). Bootjack Cyn., Muir Woods, edge of stream, 52-05-21, no collr. (1 CFMNH). Muir Woods, 52-05-21, no
collr. (2 CFMNH). Mill Valley, 52-05-17, H. Dybas (1 CFMNH). Mariposa Co.: Chowchilla Mt. rd., stream at ca.
4600’, trib. Chowchilla R., 71-08-03, H.B. Leech (6 CAS). NE slope Chowchilla Mts., 6100', bog by Stove Pipe

Western Hemisphere Hydraenidae

521

Campground, 71-08-06, H.B. Leech (1 CAS). Miami Ranger Station, 5000’, 42-06-07, H.P. Chandler (1 CAS).
Yosemite, 7000’, 34-05-20, Bryant (1 CAS). Mendocino Co.: Mendocino, 67-07-21, J.R. Heifer (3 CAS). Mendocino,
57-07-06, J.R. Heifer (1 CAS). Cold Creek, 1 mi. E. of E. Fk. Russian River, 64-10-11, H.B. Leech (1 CAS).
McDowell Cr. at foot of grade below Oasis, 1000’, 55-07-27, H.B. Leech (4 CAS). Eel River R. S., 53-08-14, P.S.
Bartholomew (4 CAS). Rancheria Cr. 5.5 mi. SE Booneville, 50-06-15, H.B. Leech (1 CAS). 15 mi. W. Willits, stream,
48-06-15, H.B. Leech (1 CAS). 5 mi. S. of Willits, 38-05-15, H.B. Leech (1 CAS). Bloody Run Cr., 7 mi. E. of route
101 on Longvale-Covelo road, 1100’, 68-07-18, H.B. Leech (5 CAS). McDowell Creek just below Oasis, 1800',
55-07-27, H.B. Leech (1 CAS). Parson Creek, 4.5 mi. NE of Hopland, 64-06-30, H.B. Leech (12 CAS). Baechtel
Creek, 3 mi. W. Willits, 48-06-15, H.B. Leech (1 CAS). Eel River, 7 mi. W„ 1450’, 72-06-10, S. Szerlip (1 UCB).
Modoc Co.: Rush Cr., 9 mi. N. Adin, 50-07-16, H.B. Leech (2 CAS). Mono Co.: Hot Creek (it was cold), 1.4 mi. W. of
Fales Hot Springs, 64-08-07, H.B. Leech (4 CAS). Monterey Co.: The Indians, 2 mi. SE Santa Lucia Memorial Park,
seepage trickle over gravelly soil, 56-01-16, H.B. Leech (1 CAS). Tassajara Hot Springs, 54-05-26, no collr. (1 CAS).
Junipero Sierra Pk., Santa Lucia Mts., Forestry Camp Springs, ca 4900’, 56-08-12, H.B. Leech (1 CAS). Carmel,
11-06-11, no collr. (1 CAS). Salinas, no date, no collr. (1 CAS). Napa Co.: Huichica Cr., 28-06-05, J.W. Tilden (2
CAS). Calistoga, 34-06-12, Bryant (4 CAS). Nevada Co.: Shotgun Lake, Bowman Mt., 6500’, 23-07-13, J.O. Martin
(15 CAS). Graniteville, 52-08-22, P.S. Partholomew (2 CAS). Riverside Co.: San Jacinto Mts., no date, F.W. Winters
(2 CAS). Riverside, no date, no collr. (1 CAS). Riverside, no date, F.E. Winters (1 OSU). ldyllwild, 70-06-30, K.
Stephan (1 KS). San Bernardino Co.: Bear Lake, 19-07-10, no collr. (1 CAS). San Benito Co.: Griswold Creek, Lyons
Cyn. on road to Idria, 63-07-21, H.B. Leech (1 CAS). San Diego CO.: Cuyamaca Lake, 61-06-11, I. Moore (1 CAS).
Poway, no date, F.E. Blaisdell (2 CAS). Camp Pendleton, Oceanside, 2000’, 45-02-11, H.P. Chandler (1 CAS). Julian,
70-06-29, K. Stephan (1 KS). No site, no date, F.E. Blaisdell (3 CAS). San Francisco Co.: San Francisco, no date,
Hubbard & Schwarz (2 USNM). San Francisco, 95-08-01, no collr. (2 MCZ). San Mateo Co.: La Honda Rd.,
51-07-14, P.S. Bartholomew (1 CAS). No site, no date, no collr. (3 CAS). Santa Barbara Co.: Cuyama River ca. 10 mi.
E. Santa Maria, 52-07-21, H.B. Leech (1 CAS). Santa Inez Mts., Santa Barbara, no date, F.E. Winters (2 CAS). Santa
Barbara, no date, F.E. Winters (8 CAS). Santa Clara Co.: Jasper Ridge, Stanford Univ., 52-05-06, P.S. Bartholomew
(101 CAS). Stanford Univ., 53-12-22, P.S. Bartholomew (1 CAS). Mts. back of Alma, 29-10-21, J.O. Martin (4 CAS).
Los Gatos, no date, Hubbard & Schwarz (12 USNM). Santa Cruz Co.: Santa Cruz, no date, F.E. Blaisdell (13 CAS).
Santa Cruz, 96-06-01, F. Nunenmacher (2 CFMNH). Santa Cruz Mts., no date, no collr. (10 CAS). Santa Cruz Mts.,
no date, A. Koebele (7 USNM). Shasta Co.: Big Springs, 4000’, 47-06-26, H.P. Chandler (2 CAS). Viola, 41-05-20, no
collr. (2. CAS). Hat Creek R.S., 3000’, 47-06-28, H.P. Chandler (2 CAS). Viola, 4500’, 47-06-27, H.P. Chandler (1
CAS). Big Spring, 41-05-29, C. Michener (1 CNC; 1 CAS). Manzanita Lake, Lassen Natl. Park, 41-06-06, C.D.
Michener (6 CAS). Siskiyou Co.: Head of W. Branch Indian Cr. at Poker Flat, 5040’, 66-08-14, H.B. Leech (1 CAS).
Sonoma Co.: Cherney Cr., 2.8 mi. S. & E. of Bodega Bay, 63-07-01, H.B. Leech (20 CAS). Mark West Cr. at Calistoga
Rd., ca 4 mi. S. of Petrified Forest, 63-07-08, H.B. Leech (10 CAS). Bennet Mt. Lk. W. of Kenwood, 1 180', 68-05-26,
H.B. Leech (2 CAS). Santa Rosa Cr., no date, Ricksecker (10 CAS). Duncan Mills, 08-07-21, F.E. Blaisdell (1 1 CAS).
Sonoma, 50-04-29, H.B. Leech (2 CAS). Duncan Mills marsh, 69-07-21, P. Rubtzoff (9 CAS). No site, no date, no
collr. (3 CAS). Fort Ross, 51-07-10, P.S. Bartholomew (10 CAS). Camp Meeker, 52-07-10, P.S. Bartholomew (9 CAS).
Camp Meeker, no date, Wintersteiner (2 OSU; 3 CAS). Cheney Cr. 2.8 mi. S. & E. of Bodega Bay, 63-07-01, H.B.
Leech (1 CAS). Tehama Co.: SW corner Tehama Co., 1 mi. SW of Government Camp, 6000', muddy pool in clear
mountain stream, 60-07-29, H.B. Leech (51 CAS). Trinity Co.: Little Brown Creek at Route 3, ca 3 mi. airline SW
Douglas City, 70-08-11, H.B. Leech (1 CAS). Van Horn Creek, 1.5 mi. above its mouth at upper Mad River, 2850’,
clear water pools and stones of otherwise dry and shaded creek bed, 70-08-09, H.B. Leech (1 CAS). Trinity Center,
36-08-23, J.T. Howell (2 CAS). Big Slide Creek, 5 mi. NW of Hyampon, 68-07-24, H.B. Leech (1 CAS). SW corner
Trinity Co., Wilson Cr. Lake Mtn. area, 60-07-30, H.B. Leech (2 CAS). Tulare Co.: Kern River, 9.5 road mi. N. of
Kernville, 70-03-25, H.B. Leech (2 CAS). Redwood Park, 23-08-09, J.O. Martin (15 CAS). Sequoia Natl. Park, F.E.
Winters (2 OSU). Tuolumne Co.: Pinecrest, 48-07-01, P.H. Arnaud, Jr., (3 CAS). Yauba Co.: Yuba City, 42-05-10,
H.P. Chandler (2 CAS). Unspecified Co.: No site, no date, no collr. (5 UNSM; 2 UW; 2 CFMNH; 10 ASP). Colorado:
Costilla Co.: Veta Pass, no date, Hubbard & Schwarz (2 CAS; 1 ASP). Veta Pass, no date, F.C. Bowditch (2 MCZ).
Idaho: Bingham Co.: No site, no date, Hubbard & Schwarz (4 CU; 13 USNM). Blaine Co.: Galena, 52-07-22, B.
Malkin (1 UWA). Clark Co.: Birch Creek, route 28, 5.4 mi. N. of Blue Dome, 69-08-24, H.B. Leech (1 CAS). Custer
Co.: 15 mi. SE of Challis, 49-07-04, H.B. Leech (1 CAS). Twin Falls Co.: Magic Hot Springs, 52-07-20, B. Malkin (1
UWA). Nevada: Elko Co.: 1000 Spring Creek, Wilkins, 49-07-03, H.B. Leech (1 CAS). Ruby Valley, no date, no collr.
(2 OSU). No site, no date, no collr. (1 CU). Oregon: Benton Co.: Monroe, 30-06-18, M.H. Hatch (6 UWA). Curry Co.:
Pistol River, 51-07-07, B. Malkin (1 CFMNH; 2 UWA). Port Orford, 51-07-07, B. Malkin (1 CFMNH; 1 UWA).
Douglas Co.: Glendale, 38-06-14, M.H. Hatch (3 UWA). Gilliam Co.: Mayville, 38-06-21, M.H. Hatch (1 UWA).
Grant Co.: Pass Cr., N. of Long Cr., 50-07-18, H.B. Leech (8 CAS). Harney Co.: Steens Mts., Fish Lake, 7500’,
51-06-26, B. Malkin (1 UWA). Fish Lake, Steens Mts., 58-08-16, J.H. Baker (1 JS). Jackson Co.: Siskiyou, 51-07-05,
B. Malkin (1 UWA). Lake Co.: Lakeview, 52-06-22, B. Malkin (22 CFMNH; 22 UWA). Chandler State Park,
51-06-30, B. Malkin (1 UWA). Linn Co.: Albany, 28-07-15, Wickham (1 CAS). Multnomah Co.: Portland, no date,
Hubbard & Schwarz (1 USNM; 3 CAS). Umatilla Co.: 7 mi. SE Milton, 49-05-04, G.H. Nelson (1 CAS). 7 mi. SE
Milton, 48-07-04, G.H. Nelson (2 UA). Wheeler Co.: Summit, Oclioco Pass, 5200’, 50-07-30, B. Malkin (1 CFMNH).

Quaest. Ent., 1980, 16 (1,2)

522

Perkins

10 mi. NNE Spray, NE Fk. Deadhorse Cr., 3178’, 64-07-06, H.B. Leech (1 CAS). Yamhill Co.: McMinnville, 42-07-05,
K.M. Fender (2 UWA). Peavine Ridge nr. McMinnville, 47-05-16, K.M. Fender (1 UWA). No site, 35-01-01, E.S.
Ross (1 CAS). Utah: Cache Co.: Logan Canyon, 7200’, 73-07-28, R. Gordon (2 RG). No site, 56-07-23, G.F. Knowlton
(2 OSU). Garfield Co.: Escalante River, mouth of Calf Creek, 39-08-04, H.P. Chandler (1 CAS). City Can., no date,
Hubbard & Schwarz (2 ASP; 1 CAS). Utah Co.: Hobble Creek Canyon, 6000', 41-07-27, H.P. Chandler (3 CAS).
Aspen Grove, 38-08-15, H.P. Chandler (2 CAS). Utah Lake, east side, 4000', 41-06-14, H.P. Chandler (2 CAS).
Wasatch Co.: Wasatch Mts., 47-06-28, Bryant (3 CAS). Washington: Kittitas Co. Ellensberg, 32-07-19, M.H. Hatch (1
UWA). San Juan Co.: San Juan Island, 30-08-02, M.H. Hatch (2 UWA). Friday Harbor, 26-08-06, no collr. (1 UWA).
Snohomish Co.: Stillaguamish, 28-04-08, no collr. (1 UWA). Whitman Co.: Wawawai, 20-07-08, M.C. Lane (1 CU; 2
CAS). Pullman, no date, C.V. Piper (4 USNM). Pullman, no date, no collr. (1 JS; 4 UWA). Colfax, 32-06-17, no collr.
(1 UWA). Wyoming: Fremont Co.: Beaver Cr. at Hwy. 28, E. slope of South Pass, 24 mi. S. & W. Lander, 65-08-22,
H.B. Leech (1 CAS).

40. Ochthebius mimicus Brown

Map: Figure 139B
Specimens examined: 15

Canada: British Columbia: Little Sand Cr., Jaffray, 50-07-23, H.B. Leech (1 CAS; 1 UBC). Fernie, 35-08-31, H.B.
Leech (1 CAS).

United States: Oregon: Multnomah Co.: Portland, no date, Hubbard & Schwarz (1 USNM). Unspecified Co.: No
site, no date, no collr. (1 CU). Washington: Chelan Co.: Leavenworth, 33-07-09, Wickham (1 USNM). Kittitas Co.:
Easton, no date, A. Koebele (2 USNM). Snohomish Co.: Sultan, 30-05-02, M.H. Hatch (1 UWA). Spokane Co.:
Spokane, 32-08-25, M.H. Hatch (2 UWA; 2 PDP). Mead, 32-08-26, M.H. Hatch (2 UWA).

42. Ochthebius similis Sharp

Map: Figure 142A
Specimens examined: 10

Mexico: Hidalgo: Pachuca, 64-08-21, P.J. Spangler (1 USNM). Vera Cruz: Highway 150, 2 mi. above Acultzingo,
48-12-14, H.B. Leech (1 CAS).

United States: Arizona: Coconino Co.: Salt Creek, no date, no collr. (2 CAS). Clear Creek Canon, no date,
Wickham (1 USNM). Navajo Co.: Winslow, no date, no collr. (3 CAS; 1 CNC). Winslow, no date, Wickham (1 MCZ).

43. Ochthebius cribricollis LeConte

Map: Figure 137
Specimens examined: 151

Canada: Alberta: Medicine Hat, 25-08-05, F.S. Carr (1 UA). British Columbia: Salmon Arm, Salmon River,
33-10-06, H.B. Leech (1 CAS). Creston, 17-05-05, W.R.S. Metcalfe (1 CAS). Osoyoos, sandy pool near Osoyoos Lake,
41-03-29, H.B. Leech (1 CAS). Edgewood, Inonoaklin River, 46-09-29, S.H. Farris (2 CAS). Lumby, 37-09-19, H.B.
Leech (1 UBC). Creston, pond meadow, 54-09-27, G. Stace-Smith (2 UBC). Cawston, 17-05-05, W. Metcalfe (2 CNC).
Manitoba: Treesbank, 4 mi. W. Hwy. 344, 68-08-14, R. Gordon (1 USNM). Aweme, 70-06-09, R. Gordon (1 RG).
Quebec: Wakefield, 30-06-04, W.J. Brown (1 CNC).

United States: California: Lake Co.: Rocky Point, Clear Lake, 47-11-09, H.P. Chandler (2 CAS). Madera Co.:
Branch, Granite Cr. 0.15 mi. W. Soldier Meadow, 6965', 71-08-17, H.B. Leech (1 CAS). Napa Co.: No site, no date, no
collr. (2 CAS). Placer Co.: Lake Tahoe, no date, Hubbard & Schwarz (2 USNM). Sacramento Co.: Grand Is.,
06-06-01, no collr. (1 CAS). San Luis Obispo Co.: Pismo Beach, 24-07-31, F.E. Blaisdell (1 CAS). Santa Barbara Co.:
Santa Barbara, no date, F.E. Blaisdell (2 UWA; 4 CAS). Santa Clara Co.: Mts. back of Alma, 29-09-29, F.E. Blaisdell
(1 CAS). Tehama Co.: Red Bluff, no date, H.P. Chandler (1 CAS). Nevada: Elko Co.: Humboldt River at Halleck,
65-08-26, H.B. Leech (1 CAS). North Dakota: Bottineau Co.: No site, 62-07-15, R. Gordon (1 USNM). Divide Co.: No
site, 63-05-23, R. Gordon (2 RG). Grand Forks Co.: Northwood, Goose River, 66-07-08, R. Gordon (1 RG). Grant Co.:
Lake Tschida, 70-05-31, R. Gordon (5 RG). Pierce Co.: No site, 63-05-14, R. Gordon (1 USNM). Renville Co.:
Sherwood, 13 mi. West, 66-05-29, R. Gordon (1 RG). Richland Co.: No site, 64-08-19, R. Gordon (4 RG). Rolette Co.:
Dunseith, nr. jet. Hwy. 3 & 43, 68-08-18, R. Gordon (2 RG). Sargent Co.: Tewaukon Ref., headq. spring, 68-08-23, R.
Gordon (2 RG). Slope Co.: No site, 62-09-13, R. Gordon & R.L. Post (1 RG). Williams Co.: Willist’n, 09-06-08,
Wickham (2 USNM). Oregon: Brenton Co.: Corvallis, no date, no collr. (7 MCZ). Corvallis, small pond, 56-04-08, K.
Goeden (1 UWA). Columbia Co.: Scappoose, mech. trap, 37-05-01, no collr. (1 JS). Deschutes Co.: 7 mi. E. Terrebone,
Hood water, 56-05-09, K. Goeden (1 UWA). Jackson Co.: Union Creek, 3100-3500’, 50-09-15, B. Malkin (1 UWA).

Western Hemisphere Hydraenidae

523

Klamath Co.: Barkley Springs, Klamath Falls, 55-06-01, J. Schuh (1 UWA). Barkley Springs, 59-09-08, J. Schuh (3
JS). 5 mi. N. Rock Point, mud bank along lake, 61-09-04, J. Schuh (5 JS). Upper Klamath Lake, under rock along
shore line, 56-05-11, J. Schuh (1 JS). Mare’s Egg Spring, 62-05-30, J. Schuh (2 JS). Sprague River, 12 mi. E.
Chiloquin, 51-07-01, B. Malkin (4 UWA; 2 CFMNH). Spring Creek Campground, 74-07-02, R. Gordon (1 RG).
Marion Co.: Salem, blk. It. trap, 58-05-01, F.P. Larson (1 UWA). Yamhill Co.: McMinnville, 40-07-15, K.M. & D.M.
Fender (1 UWA). South Dakota: Brookings Co.: Brookings, light trap, 56-07-18, H. Severin (1 SDSU). Washington:
Asotin Co.: Anatone, Grande Ronde River, 32-08-29, M.F1. Hatch (1 UWA). King Co.: Green River Gorge, 56-07-15,
B. Malkin & R. Kottke (1 CFMNH). Evans Creek, 29-06-04, M.H. Hatch (3 UWA). Bothell, 37-07-13, G. Minsk (1
UWA). Bothell, 49-04-10, no collr. (1 UWA). Snohomish Co.: N.F. Stilaguamish River, Cicero, 27-08-21, M.H. Hatch
(1 UWA). Whitman Co.: Ewan, 32-08-27, M.H. Hatch (23 UWA). Malden, 32-08-26, M. H. Hatch (1 UWA).

44. Ochthebius brevipennis new species

Map: Figure 139A
Paratypes: 31

Canada: British Columbia: Agassiz, 31-03-07, H.B. Leech (1 CAS).

United States: California: Mendocino Co.: Garcia River at Highway 1, 64-10-12, H.B. Leech (1 CAS). 2 mi. N.
Fort Bragg, marshy pond, MacKerricher St. Pk., 67-03-31, Schuh & Vertrees (4 JS). Oregon: Benton Co.: Corvallis,
small pond, 56-04-08, K. Goeden (3 ODA). Deschutes Co.: 7 mi. E. Terrebonne, flood water, 56-05-09, K. Goeden (1
ODA). Klamath Co.: 5 mi. N. Rocky Point, mud bank along lake and sweeping marsh, 61-09-04, J. Schuh (2 UWA).
Tillamook Co.: Tierra Del Mar, under rocks by lake, 38-07-27, no collr. (4 CAS). Yamhill Co.: Carlton Lake, 38-03-13,
no collr. (1 CAS). 4 mi. S. Newberg, black-lite trap, 69-08-11, no collr. (1 ODA). 5 mi. NE Newberg, black-lite trap,
66-06-22, K. Goeden (1 ODA). Washington: Cowlitz Co.: Silver Lake, 32-07-23, no collr. (6 USNM). Unspecified Co.:
Lake A., 33-07-08, T. Kincaid (6 USNM).

45. Ochthebius apache new species

Map: Figure 142A
Paratypes: 43

Mexico: Zacatecas: 29 mi. SW Zacatecas, stream in desert, 74-07-16, ME & PD Perkins (1 PDP).

United States: Arizona: Cochise Co.: Huachuca mts., Upper Carr Cyn., spring, 73-08-29, A.R Gillogly (2 AG; 8
USNM; 4 PDP). Southwestern Research Sta., 64-10-24, P.H. Arnaud, Jr. (2 CAS). Huachuca Mts., Carr Cyn., 7100',
72-05-03, A.R. Gillogly (2 AG; 4 USNM; 2 PDP). Chiric Mts., no date, Hubbard & Schwarz (2 USNM). Chiricahua
Mts., 8300’, 68-10-05, K. Stephan (3 KS). Rustler Park, Chiricahua Mts., 8300’, 52-08-26, B. Malkin (4 CFMNH).
Rustler’s Park, 56-07-08, F.N. Young (3 FNY). New Mexico: Dona Ana Co.: Organ Mts., no date, no collr. (1
USNM). Texas: Brewster Co.: Big Bend Nat. Pk., Boot Spring, 7000’, 59-05-18, Howden & Becker (3 CNC). Big Bend
N.P., Pulliam Canyon, 45-6500’, W.R. Mason (2 CNC).

49. Ochthebius apicalis Sharp

Map: Figure 142B
Specimens examined: 10

Guatemala: Huehuetenango: 35 mi. S. La Mesilla, tropical brook, 74-05-31, ME & PD Perkins (1 PDP).

Mexico: Chiapas: El Chorreadero, Chiapa de Corzo, 64-1 1-03, H.P. Brown and C.M. Shoemake (1 USNM). 27 mi.
N. Bochil, stream in pine forest, 74-05-27, ME & PD Perkins (2 PDP). Veracruz: Cordoba, no date, A. Fenyes (6
CAS).

50. Ochthebius puncticollis LeConte

Map: Figure 135C
Specimens examined: 219

Mexico: Baja California: Sa. Juarez, 2.2 mi. SE El Topo, 70-03-25, J.A. Gruwell & P.D. Perkins (4 PDP). La
Suerta, Sierra San Pedro Martir, 3700’, pool in canyon, 63-06-03, R.K. Benjamin (2 CAS).

United States: Arizona: Navajo Co.: Carrizo, 70-05-31, K. Stephan (3 KS). Pinal Co.: Riverside, no date, Wickham
(1 USNM). Pinal Mts., Craig Ranch, 57-05-20, F.H. Parker (1 UA). Unspecified Co.: No site, no date, no collr. (2
ASP). California: Contra Costa Co.: Sleepy Hollow, Orinda, stream, 38-05-03, H.B. Leech (1 CNC; 3 CAS). Humboldt
Co.: Korbel, 16-06-17, F.E. Blaisdell (1 CAS). Willow Creek, 16-06-14, F.E. Biaisdell (1 CAS). Redwood Creek,

Quaest. Ent., 1980, 16 (1,2)

524

Perkins

Redwood Valley, 3 mi. N. of road to Hoopa, 650’, 70-08-12, H.B. Leech (1 CAS). Willow Creek just above its E. Fork,
1500’, 70-08-29, H.B. Leech (3 CAS). Mill Creek, 7.5 mi. S. of Bridgeville, 1200’, 68-07-19, H.B. Leech (25 CAS). Los
Angeles Co.: San Gabriel River, W. Fork Station, 3100’, 70-08-01, P.D. Perkins (20 PDP). San Gabriel River, Whittier,
44-05-05, E. Sevy (2 CAS). Santa Monica, 17-03-17, J.O. Martin (1 CAS). Marin Co.: McClures Bch., Pt. Reyes Pen.,
61-07-07, H.B. Leech (22 CAS). Point Reyes National Seashore Firebreak trail between Sky Camp & Coast Camp,
68-05-01, P.S. Bartholomew (2 CAS). Lagunitas creek at Tacoloma, 68-05-04, H.B. Leech (17 CAS). Mendocino Co.:
Mendocino, amongst roots Mimulus guttatus, 57-07-06, J.R. Heifer (8 CAS). Mendocino, 57-07-21, J.R. Heifer (24
CAS). James Creek, Hwy. 20, 12.5 mi. W. of Willits, 64-10-11, H.B. Leech (6 CAS). No site, no date, no collr. (7
CAS). Monterey Co.: Del Monte, 20-09-11, F.E. Blaisdell (1 CAS). Marina, 20-09-14, F.E. Blaisdell (2 CAS). Carmel,
14-03-05, no collr. (2 CAS). Tassjara Hot Springs, 3000’, 54-05-23, Bryant (1 CAS). Riverside Co.: Palm Canyon,
16-04-15, J.O. Martin (1 CAS). Palm Springs, 17-05-25, J.O. Martin (9 CAS). San Jacinto Mts., no date, F.E. Winters
(6 CAS). Riverside, no date, F.E. Winters (3 CAS). San Bernardino Co.: Bear lake, 19-07-10, J.O. Martin (1 CAS).
Yermo, 37-04-28, H.B. Leech (1 CAS). San Diego Co.: Poway, no date, F.E. Blaisdell (1 CAS). Julian, 70-06-29, K.
Stephan (3 KS). San Luis Obispo Co.: Santa Lucia Range, 2500’, 54-06-01, Bryant (1 CAS). San Mateo Co.: Lobitos
Cr., 25 mi. S. Half Moon Bay, 64-09-21, H.B. Leech (1 CAS). Santa Barbara Co.: Santa Cruz Island, 70-09-20, P.D.
Perkins (1 PDP). Santa Barbara Mts., no date, no collr. (2 MCZ). Siskiyou Co.: Shasta Retreat (now part of
Dunsmuir), no date, F.E. Blaisdell (1 CAS). Crawford Creek, 1.7 mi. N. of Cecilleville, 68-07-29, H.B. Leech (2 CAS).
Trinity Co.: Big Slide Creek, 5 mi. NW Hyampon, 68-07-24, H.B. Leech (12 CAS). Ventura Co.: Sespe Cr., Sespe
Gorge, 3500’, 72-06-18, P.D. Perkins (1 PDP). Unspecified Co.: No site, no date, no collr. (1 CAS; 1 ASP). Utah:
Garfield Co.: Escalante River, mouth of Calf creek, 39-08-04, H.P. Chandler (1 CAS). Washington Co.: St. George, no
date, Wickham (1 MCZ). Zion Nat. Pk., 47-06-26, B. Malkin (1 BMNH). Unspecified Co.: Chad’s Ranch, no date,
Wickham (3 MCZ; 2 CAS).

51. Ochthebius martini Fall

Map: Figure 135C
Specimens examined: 43

United States: California: Humboldt Co.: Redwood Park, 18-08-10, J.O. Martin (1 USNM: 4 MCZ; 12 CAS).
Redwood Park, 23-08-09, J.O. Martin (4 CAS). Mill Creek, 7.5 mi. S. of Bridgeville, 1200’, 68-07-19, H.B. Leech (7
CAS). No site, no date, no collr. (2 CAS). San Mateo Co.: La Honda Rd., 55-05-22, P.S. Bartholomew (1 CAS). La
Honda, 47-05-04, D. Giuliani (2 CAS). Santa Clara Co.: Mt. back of Alma, 29-11-29, J.O. Martin (1 CAS). San
Martin, 52-06-26, P.S. Bartholomew (1 CAS). Los Gatos, no date, Hubbard & Schwarz (2 USNM). Los Gatos, no
date, no collr. (1 ASP). Santa Cruz Co.: Santa Cruz Mts., no date, A. Koebele (5 USNM).

52. Ochthebius angularidus new species

Map: Figure 142A
Paratypes: 26

Mexico: Coahuila: Same data as Holotype (2 HPB; 6 PDP; 6 USNM). Nuevo Leon: Rio Cabisones, near Linares,
64-10-09, H.P. Brown & C.M. Shoemake (2 USNM).

United States: Texas: Pecos Co.: Pecos River, Sheffield, 67-08-25, H.P. Brown (1 USNM). Val Verde Co.: Devil’s
River, 07-05-07, Schwarz, Pratt & Bishop (5 USNM; 2 PDP). Devil’s River, Compton, 72-03-22, H.P. Brown (2
USNM).

53. Ochthebius leechi Wood and Perkins

Map: Figure 135C
Specimens examined: 96

United States: California: Colusa Co.: Sulphur Cr. at Wilbur Hot Sprs., flood pool, 56-03-29, H.B. Leech (2 CAS).
Sulphur Cr. at Wilbur Springs, 1345’, 71-04-05, H.B. Leech (41 CAS; 3 USNM; 3 MCZ; 3 CNC). Wilbur Springs,
1250’, 71-06-17, P.D. Perkins (12 USNM). Glenn Co.: Salt Cr. at Stony Cr., N of Stonyford, 56-03-29. H.B. Leech (16
CAS). Trib. to Stony Cr., 7 mi. N. Stonyford, 56-03-29, H.B. Leech (15 CAS). Marin Co.: Sleepy Hollow, Orinda,
38-05-03, H.B. Leech (1 CAS).

1. Neochthebius vandykei (Knisch)

Map: Figure 139C

Western Hemisphere Hydraenidae

525

Specimens examined: 257

Canada: British Columbia: Massett, Queen Charlotte Islands, no date, Keene (5 USNM). Metlaktla, no date, Keene
(5 USNM). Metlaktla, no date, no collr. (1 MCZ). Brunswick, 68-05-20, Campbell & Smetana (4 CNC). Long Beach,
12 mi. S. Tofino, 68-05-22, Campbell & Smetana (4 CNC).

United States: California: Contra Costa Co.: Jasper Ridge, Stanford Univ., 52-05-31, P.S. Bartholomew (8 CAS).
Humboldt Co.: Patrick’s Point, 64-07-01, D. Giuliani (2 CAS). Los Angeles Co., Vicente Pt., 64-06-01, D. Giuliani (5
CAS). Marin Co.: Pt. Diablo, 64-07-01, D. Giuliani (2 CAS). Dillon Bch., 64-08-01, D. Giuliani (2 CAS). Strawberry
Pt., 64-06-01, D. Giuliani (2 CAS). Agate Beach, 71-03-30, D. Giuliani (4 CAS). Willow Camp, 21-04-10, E.C. Van
Dyke (5 CAS). Pt. Reyes, 65-02-01, D. Giuliani (5 CAS). Pt. San Pedro, 65-04-01, D. Giuliani (17 CAS). Needle Rock,

64- 10-01, D. Giuliani (3 CAS). Muir Beach, 64-06-01, D. Giuliani (2 CAS). Rocky Point, 64-08-01, D. Giuliani (1
CAS). Gull Rock, 64-08-01, D. Giuliani (1 CAS). Spindrift Point, 64-07-01, D. Giuliani (1 CAS). Mendocino Co.: 1 mi.
N.S. Kibesillah 64-08-01, D. Giuliani (2 CAS). Point Arena, 65-06-0 1 , D. Giuliani (3 CAS). 7 mi. N. Havensneck,

65- 06-01, D. Giuliani (3 CAS). Monterey Co.: Pacific Grove, 50-10-04, I. Moore (1 CNC). Big Sur, 38-04-01, E.C. Van
Dyke (11 CAS). Pt. Pinos, crevices, intertidal rocks, 49-08-25, T. Aarons (6 CAS). San Francisco Co.: Bayview Park,
San Francisco Bay, 53-08-23, F.L. Rogers (2 USNM). San Luis Obispo Co.: Pismo Beach, 24-07-31, F.E. Blaisdell (1
MCZ). Shell Beach, 50-10-07, I. Moore (4 CAS; 1 CNC). San Mateo Co.: Moss Beach, many dates between 1910 and
1965, many collectors, including E.C. Van Dyke, F.E. Blaisdell, J.O. Martin, D. Giuliani, and T. Erwin (124 CAS; 6
USNM: 4 OSU; 1 CNC; 1 MCZ). Ano Nuevo Isl., 65-07-01, D. Giuliani (3 CAS). Pillar Pt., 65-06-01, D. Giuliani (6
CAS). Sonoma Co.: Goat Rock, 64-08-01, D. Giuliani (1 CAS). Stewarts Point, 64-08-01, D. Giuliani (1 CAS). Duncan
Point, 65-01-01, D. Giuliani (1 CAS). Fort Ross, 27-10-06, E.C. Van Dyke (3 CAS). Bodega Head, 64-08-01, D.
Giuliani (2 CAS).

APPENDIX B: TABULAR SUMMARY

specimens

aedeagi

species

species

species

examined

examined

described

described

total

previously

herein

Hydraenida

15

6

1

1

2

Parhydraenida

57

17

4

5

9

Neochthebius

257

6

1

0

1

Meropathus

3

0

0

1

1

Gymnochthebius

1,212

175

11

14

25

Ochthebius

9,794

1,210

23

30

53

Hydraena

7,102

2,722

18

77

95

Spanglerina

288

22

1

3

4

Limnebius

2,522

1,060

5

11

16

21,250

5,218

64

142

206

Quaest. Ent., 1980, 16 (1,2)

526

Perkins

Figs. 189A - C. (A) type-locality of Hydraena appalachicola. United States, Virginia, Bath County, two miles south of
Mountain Grove, Blowing Springs public camp. (B) biotope of Hydraena angulicollis. United States, Maine, Hancock
County, Bucksport. (C) type-locality of Hydraena canticacollis , Mexico, Zacatecas, thirteen miles south of Jalpa.

Western Hemisphere Hydraenidae

527

Figs. 190A - B. (A) type-locality of Hydraena splecoma , Mexico, Chiapas, four miles N. Bochil. (B) microhabitat at
type-locality of H. splecoma ; area is at base of undercut bank in left portion of figure A.

Quaest. Ent., 1980, 16 (1,2)

528

Perkins

Figs. 191 A - C. (A) biotope of Limnebius alutaceus and Ochthebius bisinuatus. United States, Montana, Ravalli County,
Mill Creek at highway 93, seven miles N. of Hamilton. (B) type-locality of Hydraena oblio , Guatemala, Baja Verapaz,
four miles S. of Rabinal. (C) as above, overview.

Western Hemisphere Hydraenidae

529

Figs. 192A - B. (A) type-locality of Hydraena chiapa , Mexico, Chiapas, nine miles N. of Tapilula; note collecting
technique. (B) as above, overview.

Quaest. Ent., 1980, 16 (1,2)

530

Perkins

Figs. 193A - B. (A) type-locality of Hydraena sabella , Mexico, Chiapas, eight miles W. of Teapa; Gymnochthebius
fossatus also taken at this locality. (B) type-locality of Hydraena maureenae and Limnebius ozapalachicus. United States,
Virginia, Bath County, twelve miles S. of Williamsville.

Western Hemisphere Hydraenidae

531

Figs. 194A - C. (A) type-locality of Hydraena d-destina , Mexico, Chiapas, 27 miles N. of Comitan; Ochthebius
mesoamericanus also taken at this site. (B) as above, microhabitat. (C) biotope of Hydraena marginicollis , United States,
Florida, Alachua County, Payne’s Prairie.

Quaest. Ent., 1980, 16 (1,2)

532

Perkins

Figs. 195A - C. (A) type-locality of Hydraena colymba , Guatemala, Jalapa, six miles N. of Jalapa; specimens of
Limnebius sinuatus were also found at this site. (B) type-locality of Spanglerina fluvicola, Hydraena cuspidicollis and
Hydraena scintilla , Mexico, Oaxaca, one mile N. Ixtlan de Juarez; Spanglerina brevis was also collected at this locality.
(C) microhabitat of Spanglerina fluvicola at type-locality; specimen was removed from submerged limb.

Western Hemisphere Hydraenidae

533

Figs. 196A - C, Biotopes of Spanglerina brevis. (A) Guatemala, Alta Verapaz, 20 miles W. of La Tinta. (B) Mexico,
Oaxaca, eight miles E. of Tapanatepec. (C) Mexico, Chiapas, nine miles N. of Tapilula.

Quaest. Ent., 1980, 16 (1,2)

534

Perkins

Figs. 197A - B. (A) biotope of Spanglerina brevis , Guatemala, Alta Verapaz, five miles W. La Tinta; note collecting
technique, compare with Fig. 192A. (B) microhabitat of Spanglerina ingens at type-locality, Mexico, Mexico, 1 1 miles S.
Valle de Bravo.

Western Hemisphere Hydraenidae

535

Figs. 198A - C, Biotope of Neochthebius vandykei , Marin Peninsula, Marin County, California. (A) overview; note arrow
indicating microhabitat. (B-C) microhabitat; note arrows indicating cracks in rocks from which beetles were collected.
(Photographs courtesy of Alan R. Gillogly.)

Quaest. Ent., 1980, 16 (1,2)

536

Perkins

ACKNOWLEDGEMENTS

Numerous individuals and institutions have aided this study, to them I extend my hearty
thanks.

First and foremost, I thank my wife Maureen Ellen for her constant encouragement, for the
many sacrifices she has made during the course of this study, and for help with field work.

Paul J. Spangler, National Museum of Natural History, Smithsonian Institution, has been
an unending source of assistance, providing material support of many kinds, including work
space and equipment, aid with the literature, and help with scanning electron microscopy. He
has unselfishly provided the fruits of his extensive field work throughout the Western
Hemisphere, and has made special efforts to provide specimens for this study. For these
kindnesses, encouragement and friendly advice, to him I extend my sincerest gratitude.

Special thanks are due Hugh B. Leech, California Academy of Sciences, for suggesting that
this family was in need of study, and for making available a wealth of meticulously mounted
material which is the result of an extensive investment of time, patience, and energy, both in the
field and in the laboratory.

I am very grateful to Allan R. Gillogly, who collected and sent many preserved and living
specimens, and who graciously provided the photographs of the intertidal habitat of
Neochthebius vandykei.

Harley P. Brown, David C. Miller, Warren E. Steiner and Frank N. Young have kindly
provided specimens from their collections, for which I am grateful. Many other individuals and
institutions have provided specimens for this study, to them I extend my thanks.

I thank Peter Hammond and Mick Bacchus of the British Museum (Natural History), A1
and Margaret Newton of the Museum of Comparative Zoology, Harvard University, and G.
Demoulin and entomologists at the Institut royal des Sciences Naturelles de Belgique
(Brussels) for their hospitality and assistance during my visits to their collections.

I also thank Ms. Mary Jacque Mann and Mrs. Susann Braden, Smithsonian Institution
scanning electron microscopists, for taking the micrographs. I am grateful to members of the
systematic theory discussion group at the National Museum of Natural History, including
Wayne Clark, Terry Erwin, Chris Thompson and Don Whitehead (and participants from
non-Entomology disciplines), for many stimulating sessions.

Terry L. Erwin and Paul J. Spangler kindly reviewed and criticized the manuscript. I also
gratefully acknowledge the editorial modifications made by George E. Ball, which improved
the manuscript significantly.

Funding for this study was provided in part by a one year research Fellowship at the
Smithsonian Institution’s Department of Entomology (1974), for which I am most grateful.
One additional year (1973) was supported by a teaching assistantship at the Department of
Entomology, University of Maryland, while I was a graduate student at that institution. The
remaining years (1972, 1975-1979) were supported by my wife and myself by working at
various temporary jobs.

Western Hemisphere Hydraenidae

537

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Western Hemisphere Hydraenidae

541

Orchymont, A.d’ 1932a. Notes sur certains sous-genres d 'Ochthebius ( Calobius , Cobalius ,
etc.). Ibid., 72: 41-52.

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Hydraenidae). Memoirs du Musee Royal d’Histoire Naturelle de Belgique, Deuxieme serie,
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Orchymont, A.d’ 1936b. Les Hydraena de la Peninsule Iberique. Ibid., Deuxieme serie, 6:
1-48.

Orchymont, A.d’ 1937. Contribution a l’etude des Palpicornia. X. Bulletin et Annales de la
Societe Entomologique de Belgique, 77: 458-475.

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Annales de la Societe Entomologique de Belgique, 78(7): 275-291.

Orchymont, A.d’ 1940. Notes sur quelques Ochthebius ( Asiobates ) du groupe bicolon (Col.
Palpicornia). Bollettino della Societa Entomologica Italiana, 72(4): 53-61 .

Orchymont, A.d’ 1941a. Revision des Ochthebius Europeens du sous-genre Henicocerus
Stephens, 1829 (Coleoptera Palpicornia). Bulletin du Musee royal d’Histoire naturelle de
Belgique, 17(12): 1-15.

Orchymont, A.d’ 1941b. Nouvelles notes sur quelques Ochthebius Palearctiques du sous-genre
Asiobates (Coleoptera Hydraenidae). Ibid., 17(8): 1-23.

Orchymont, A.d’ 1942a. Revision du sous-genre Homalochthebius Kuwert, 1887 du genre
Ochthebius Leach (Coleoptera Hydraenidae). Ibid., 18(39): 1-16.

Orchymont, A.d’ 1942b. Le complexe Ochthebius ( Hymenodes ) foveolatus Auct. (Coleoptera
Palpicornia Hydraenidae). Ibid., 18(45): 1-16.

Orchymont, A.d’ 1942c. Le groupe de 1’ Ochthebius ( Hymenodes ) metallescens Rosenhauer
(Coleoptera Palpicornia Hydraenidae). Ibid., 18(51): 1-16.

Orchymont, A.d’ 1943a. Contribution a l’etude du sous-genre Ochthebius (s. str.) Kuwert,
1887 (Coleoptera Palpicornia Hydraenidae). Ibid., 19(10): 1-24.

Orchymont, A.d’ 1943b. Faune du nord-est bresilien (recoltes du Dr. O. Schubart).
Palpicornia. Memoires du Musee royal d’Histoire Naturelle de Belgique, deuxieme serie,
28: 1-85.

Orchymont, A.d’ 1945a. Hydraena (5. str.) de la Guadeloupe (Coleoptera Palpicornia
Hydraenidae). Bulletin du Musee royal d’Histoire naturelle de Belgique, 21(3): 1-4.

Orchymont, A.d’ 1945b. Notes nouvelles sur le genre Limnebius (Coleoptera Palpicornia
Hydraenidae). Ibid., 21(6): 1-24.

Orchymont, A.d’ 1948. Mission scientific de l’Omo (Coleoptera: Hydraenidae). Memoires du
Museum National d’Histoire Naturelle, nouvelle serie, 27(2): 29-61.

Ordish, R.G. 1971. Entomology of the Aucklands and other islands south of New Zealand:
Coleoptera: Hydraenidae. Pacific Insects Monographs, 27: 185-192.

Paulian, R. 1941. Les premiers etats des Staphylinoidea. Memoires du Museum National
d’Histoire Naturelle, 15(1), 361 pages.

Quaest. Ent., 1980, 16 (1,2)

542

Perkins

Paykull, G. von 1798. Fauna Suecica: Insecta, vol. 1, p. 245. Upsaliae.

Perkins, P.D. 1975. Gender points: a timesaver for microcoleopterists. Coleopterists Bulletin,
25(2): 84.

Perkins, P.D. 1976. Psammophilous aquatic beetles in southern California: A study of
microhabitat preferences with notes on responses to stream alteration (Coleoptera:
Hydraenidae and Hydrophilidae). Ibid., 30(4): 309-324.

Platnick, N.I. 1976. Drifting spiders or continents?: Vicariance biogeography of the spider
subfamily Laroniinae (Araneae: Gnaphosidae). Systematic Zoology, 25: 101-109.

Platnick, N.I. and G. Nelson. 1978. A method of analysis for historical biogeography.
Systematic Zoology, 27: 1-16.

Rey, C. 1884. Histoire naturelle des coleopteres de France. Annales de la Societe Linneenne de
Lyon, 31 .

Richmond, E.A. 1920. Studies on the biology of the aquatic Hydrophilidae. Bulletin of the
American Museum of Natural History, 42: 1-94.

Rocha, A. A. 1967. Biology and first instar larva of Epimetopus trogoides (Col.,
Hydrophilidae). Papeis Avulsos de Zoologia, 20: 223-228.

Rosen, D.E. 1975. A vicariance model of Caribbean biogeography. Systematic Zoology, 24:
431-464.

Rosen, D.E. 1978. Vicariant patterns and historical explanation in biogeography. Ibid., 27:
159-188.

Samuelson, G.A. 1964. Insects of Campbell Island. Appendix. Coleoptera. Hydraenidae,
Leptodiridae (Larvae). Pacific Insects Monographs, 7: 624-627.

Sato, M. 1963. A new inter-tidal species of the genus Ochthebius Leach from Japan
(Coleoptera: Hydraenidae). Transactions of the Shikoku Entomological Society, 7(4):
129-132.

Sharp, D. 1882. Biologia Centrali-Americana, Insecta, Coleoptera, Haliplidae, Dytiscidae,
Gyrinidae, Hydrophilidae, Heteroceridae, Parnidae, Georissidae, Cyathoceridae. 1(2):
1-144.

Sharp, D. 1887. Biologia Centrali-Americana, Insecta, Coleoptera, Supplement. 1(2):
673-802.

Spangler, P. J. 1980. Two new species of aquatic beetles of the genus Hydraena from Cuba
(Coleoptera:Hydraenidae). Proceedings of the Entomological Society of Washington,
82(2):329-333.

Spangler, P.J. and P.D. Perkins. 1977. Three new species of the neotropical water beetle genus
Elmoparnus (Coleoptera: Dryopidae). Proceedings of the Biological Society of Washington,
89(63): 743-760.

Stephens, J.F. 1839. A manual of British Coleoptera or beetles. 443 pages.

Thomson, C.G. 1859. Skandinaviens Coleoptera, synoptiskt bearbetade. Vol. I. Lund.

Van Dyke, E.C. 1918. New inter-tidal rock-dwelling Coleoptera from California.
Entomological News, 29(8): 303-308.

Wood, F.E. and P.D. Perkins. 1978. Two new species of Nearctic Ochthebius (Coleoptera:
Hydraenidae). Coleopterists Bulletin, 32(1): 53-58.

Young, F.N. 1954. The water beetles of Florida. University of Florida Studies, Biological
Science Series, 5(1): 238 pages.

Western Hemisphere Hydraenidae

543

Zaitzev, P.A. 1908. Catalogue des coleopteres aquatiques des families des Dryopidae,
Georyssidae, Cyathoceridae, Heteroceridae, et Hydrophilidae. Horae Societatis
Entomologicae Rossicae, 38: 283-420.

Zwick, P. 1975. A new Orchymontia (Coleoptera, Hydraenidae) from New Zealand. Nouvelle
Revue d’Entomologie, 5(3): 247-250.

Zwick, P. 1977. Australian Hydraena (Coleoptera: Hydraenidae). Australian Journal of
Zoology, 25: 147-184.

Quaest. Ent., 1980, 16 (1,2)

544

Perkins

Index to Names of Taxa

FAMILY GROUP TAXA
Hydraenidae, 3,8,9, 10, 11, 12, 13,

17, 33, 48, 63, 222, 331, 351, 407, 410,
411,412, 429,431,471
Hydraeninae, 3, 9, 215, 411, 412, 427,
430

Limnebiidae,

Limnebiinae,

Ochthebiinae,

Spercheinae,

9

3,9,411,427,430
3, 247, 430
9

GENERA AND SUBGENERA
Acanthochthebius Kuwert , 409

Asiobates Stephens
(subgenus of

Ochthebius), 23, 35, 39, 293, 295,
298, 303, 374, 376, 391, 394, 403, 409,
436, 460, 461,468
Bilimneus Rey (subgenus of
Limnebius), 20, 407
Callilepis, 475
Calobius Wollaston, 293, 409
Chaetarthria, 1 1
Cobolius Wollaston, 409
Coelometopon Janssens, 40, 413, 417,
430, 434

Doryochthebius Kuwert, 293, 409
Epimetopus, 429
Grammhydraena Kuwert, 60
Gymnochthebius

(LeConte), 283
Gymnochthebius

d’Orchymont, 3, 13, 16, 17, 19, 20,
21, 23, 29, 33, 35, 38, 244 , 245, 247,
248, 251, 252, 253, 254, 273, 276, 286,
289, 290, 292, 293, 298, 417, 430, 431,
434, 437,455,459,476,482
Hadrenya Rey, 60
Haenydra Rey (subgenus of

Hydraena), 20, 60, 61, 212, 407,
412

Helophorus, 429

Henicocerus Stephens, 286, 374, 409,
464

Holcohydraena Kuwert, 60, 61
Homalochthebius Kuwert
(subgenus of

Ochthebius), 293, 295, 388, 469
Hoplydraena Kuwert, 60
Hydraena (sensu stricto ), 60, 61, 62,

407,412

Hydraena Kugelann, 3, 6, 9, 11, 12,

13, 15, 16, 19, 20, 22, 23,32,33,35,
36, 60, 61,62,63,64, 103, 116,211,
212, 215, 372, 407, 411, 412, 413, 417,
419, 427, 428, 429, 430, 431, 434, 435,
437, 440, 444, 475, 476, 479, 480, 482
Hydraenida Germain, 3, 17, 20, 34,

36, 40, 41, 45, 48, 417, 428, 429, 430,
431,434, 438

Hydraenopsis Janssens, 62
Hymenodes Mulsant
(subgenus of
Ochthebius), 295
Laccobius, 1 1

Laeliaena Sahlberg, 412,413,430
Limnebius ( sensu stricto), 407
Limnebius Leach, 3, 9, 11, 17, 18, 19,
20, 29, 33, 35, 38, 222, 225, 407, 411,
412, 413, 417, 418, 419, 427, 428, 429,
430, 431, 436, 437, 455, 475, 476, 477,
479, 482

Limnocharis Horn, 222
Meropathus Enderlein, 3, 17, 20, 33,
34, 39, 292, 293, 406, 407, 409, 410,
417, 419, 429, 430, 431, 434, 436, 471
Neochthebius d’Orchymont, 3, 1 1, 34,
39, 293, 407, 408, 417, 419, 429, 430,
436, 471,482
Ochthebius (Asiobates

Stephens), 23, 35, 39, 293, 295,
298, 303, 374, 376, 391, 394, 409, 436.
460, 461,468
Ochthebius

(Homalochthebius
Kuwert), 293, 295, 388, 469
Ochthebius (Hymenodes
Mulsant), 295

Western Hemisphere Hydraenidae

545

Ochthebius (LeConte), 284
Ochthebius ( sensu strictoj, 20, 23, 35,

295, 435, 459, 460, 462
Ochthebius ( sensu stricto)
d’Orchymont, 407, 409
Ochthebius {sensu stricto)

Leach, 38, 245, 252, 293, 298, 299,
305, 325, 346, 374, 407, 435, 464
Ochthebius Leach, 3, 6, 9, 11, 13, 16,
21,23,33,35, 38,60, 63, 244, 245,
247, 252, 292, 293, 295, 298, 315, 318,
343, 352, 374, 388, 389, 407, 409, 410,
41 1, 412, 413, 417, 418, 419, 427, 428,
429, 430, 431, 435, 437, 455, 460, 477,
479, 480, 482

Ochthebius LeConte, 284
Oocyclus, 369
Parhydraenida

J. Balfour-Browne, 3, 11, 13, 17,
21,33,34, 36, 40,41,45, 48,51,59,
428, 429, 430, 431, 434, 435, 438, 482
Phothydraena Kuwert, 60,61
Spanglerina, new genus, 3, 11, 12, 15,
33, 35, 38, 63, 212, 215, 216, 372, 429,
455,480

Sphaenhydraena Kuwert, 60
Taenhydraena Kuwert, 60, 61, 116

SPECIES AND SUBSPECIES
aberti Hatch, Ochthebius, 7, 295, 311,
312

aeneus Germain,

Ochthebius, 256
alida J. Balfour-Browne,

Parhydraenida, 36, 49, 57
alpinopetrus new species,

Ochthebius, 6, 39, 302, 357, 359,
464,517

alternata new species,

Hydraena, 6,36,66, 116,495
alternata Subgroup,

Hydraena, 29,33,7/6,435
alterra new species,

Hydraena, 6, 36, 67, 118, 121, 122,
123,445
alutacea Casey,

Limnocharis, 230
alutaceus (Casey),

Limnebius, 7, 38, 225, 226, 230,
455, 500

anaphora new species,

Hydraena, 6,37,71,775,454

ancylis new species,

Hydraena, 6, 36, 64, 82, 96, 97, 99,
100, 148, 441, 444, 475, 479, 492
angularidus new species,

Ochthebius, 6, 39, 303, 399, 400,
402, 403, 468, 479, 524
angulicollis Complex,

Hydraena, 36, 72, 82, 440, 444,

475

angulicollis Notman,

Hydraena, 36, 62, 64, 82, 83, 96,

97, 435, 440, 441, 444, 475, 486
angustula Casey,

Limnocharis, 238
angustulus (Casey),

Limnebius, 38, 226, 238, 455

anisonycha Complex,

Hydraena, 37,797,435,450

anisonycha new species,

Hydraena, 6, 12, 16,23,37,70,

164,797,452, 498
apache new species,

Ochthebius, 6, 39, 304, 391, 470,

480, 523

apicalis Sharp, Ochthebius, 39, 304,
393, 397, 470, 523
appalachicola new species,

Hydraena, 6, 36, 64, 83, 92, 444,

475

arenicola new species,

Hydraena, 6, 36, 65, 75, 444, 484

arenicolus new species,

Limnebius, 3, 38, 226, 234, 427,
455,479, 501
arenicolus new species,

Ochthebius, 6,39,301, 306, 307,
313, 356,466, 506
argutipes new species,

Hydraena, 6, 37, 68, 158, 449, 480
argutipes Subgroup,

Quaest. Ent., 1980, 16 (1,2)

546

Perkins

Hydraena, 37, 757, 448

aridus new species,

Limnebius, 6,38,226,247,455
arizonica new species,

Hydraena, 6,32,36,66,67,103,

108, 392, 445,494
arizonicus new species,

Ochthebius, 6, 39, 303, 365, 366,

464, 477,479,519
atlantica Complex,

Hydraena, 36, 72, 85, 441, 444,

475

atlantica new species,

Hydraena, 6, 29, 36, 64, 85, 86,

148,444, 475,488
attritus LeConte,

Ochthebius, 7, 12, 39, 245, 293,

295, 299, 301, 31 1, 346, 349, 437, 464,
466,516

aztecus Sharp, Ochthebius, 7, 39, 295,

301,346, 359, 518
barricula new species,

Hydraena, 6,37,71, 164 ,202
bartyrae new species,

Gymnochthebius, 6, 38, 249, 256,
270, 459

batesoni Blair, Ochthebius, 20, 39,

299, 301, 306, 311, 346, 349, 464, 516
benefossus Group,

Ochthebius, 39, 299, 374, 435, 464

benefossus LeConte,

Ochthebius, 39, 295, 299, 374,

435, 462, 464, 520
biincisus Group,

Ochthebius, 23, 293, 299, 345,

355, 435, 461, 462, 463, 464, 466, 470,
479

biincisus new species,

Ochthebius, 6, 39, 302, 346, 352,

353, 361, 464, 477,479,518
bisagittatus new species,

Gymnochthebius, 6, 38, 250, 264,
459

bisinuatus Group,

Ochthebius, 23, 299, 332, 345,

435, 462, 463, 464, 466

bisinuatus new species,

Ochthebius, 6, 39, 299, 336, 337,
338,339, 341,514
bituberculata new species,

Hydraena, 6, 23, 36, 63, 65, 103,
109, 392, 445, 495
borealis new species,

Limnebius, 6, 38, 225, 226, 235,
455, 479, 502
borealis new species,

Ochthebius, 6, 39, 300, 314, 322,
325,355,436, 466,511
borealis Subgroup,

Ochthebius, 39,300,574,321,

322, 355, 462, 464, 466
bractea new species,

Hydraena, 6, 37, 68, 152, 7 60, 161,

449

bractoides new species,

Hydraena, 6,37,68,152,160,767,

449

breedlovei new species,

Hydraena, 6, 36, 66, 67, 106, 445,

494

brevipennis new species,

Ochthebius, 6, 39, 295, 305, 389,

523

brevis (Sharp), Spanglerina, 12, 19,
38,216,219, 220, 455,480, 499
brevis Group, Spanglerina, 38,216,
219

brevis Sharp, Hydraena, 220
browni new species,

Hydraena, 6, 1 9, 37, 72, 180, 454
browni new species,

Ochthebius, 6, 39, 304, 393, 470

bruesi Darlington,

Ochthebius, 7, 295, 360

bubrunipes new species,

Parhydraenida, 3,36,45,49,57,
439

californica new species,

Hydraena, 6, 36, 65, 88, 89, 444,
477, 490

californicus new species,

Ochthebius, 6,23,39,299,313,

Western Hemisphere Hydraenidae

547

338, 339, 341,465, 465,515
campbellensis Brookes,

Meropathus, 1 7, 408, 434, 47 1
campbelli new species,

Hydraena, 6, 37, 67, 132, 445, 446,
472, 476, 480
canticacollis new species,

Hydraena, 6,36,66,773,444
chiapa new species,

Hydraena, 6, 38, 69, 206, 207, 454
chilenus

(J. Balfour-Browne),

Gymnochthebius, 38, 250, 256,

257, 261,262, 503
chilenus J. Balfour-Browne,

Ochthebius, 257
chuni Enderlein,

Meropathus, 407,408,471
circulata Complex,

Hydraena, 36, 74, 440, 44 1 , 444
circulata Group, Hydraena, 15, 36, 64,
72, 92, 212, 431, 435, 440, 444, 475,
476, 477, 479
circulata new species,

Hydraena, 6, 29, 36, 63, 65, 74, 15,
101, 392, 427,444, 482
clandestinus new species,

Gymnochthebius, 6, 38, 250, 256,

258, 262, 503
colombiana new species,

Hydraena, 6,33,36,67, 118, 727,
445

columbianus Brown,

Limnebius, 7, 33, 232
colymba Complex,

Hydraena, 37, 793, 452, 454

colymba new species,

Hydraena, 6, 37, 72, 793, 452, 498
compactus new species,

Gymnochthebius, 6, 38, 249, 267,
459

congener (Casey),

Limnebius, 7

congener Casey,

Limnocharis, 232
coniciventris (Casey),

Limnebius, 7

coniciventris Casey,

Limnocharis, 238
costiniceps new species,

Hydraena, 6, 36, 67, 124, 126, 445,

446

costipennis Fall,

Ochthebius, 39, 299, 313, 341, 515

crassalus new species,

Ochthebius, 6, 39, 299, 343

crassipes (Sharp),

Gymnochthebius, 38, 248, 283,

284, 286, 459
crassipes Sharp,

Ochthebius, 284

crenatus Hatch,

Ochthebius, 39, 299, 343, 464,

465, 515

cribricollis LeConte,

Ochthebius, 39, 293, 295, 298,

305, 388, 389, 391,469, 522
cribricollis Subgroup,

Ochthebius, 39, 304, 388, 468,

469, 479

crystallina new species,

Hydraena, 6, 37, 68, 1 15, 755

curvus new species,

Gymnochthebius, 6, 38, 249, 262
cuspidicollis new species,

Hydraena, 6, 12,37,68, 112, 115,

152, 153, 162, 448,449,497
d-destina new species,

Hydraena, 6,23,32,37,71, 164,

200, 202

decui Spangler, Hydraena, 37, 69, 70,

144, 448

discolor Casey, Limnebius, 38, 84,

140, 225, 227, 499
discretus (Asiobates),

Ochthebius, 23, 436

discretus Group,

Ochthebius, 39, 303, 376, 468

discretus LeConte,

Ochthebius, 7, 20, 39, 295, 303,

377, 380, 382, 468, 520
discretus Subgroup,

Quaest. Ent., 1980, 16 (1,2)

548

Perkins

Ochthebius, 39, 303, 376, 385,

468, 470, 477, 479
effeminata

J. Balfour-Browne,

Parhydraenida, 36, 49, 54, 439
elegans Janssens,

Ochthebius, 293
exarata Kiesenwetter,

Hydraena, 61,116
exilipes new species,

Hydraena, 6, 33, 37, 68, 118, 1 33,
445, 446, 472, 476, 480
falli new species,

Gymnochthebius, 6, 38, 248, 274,
276, 279, 281, 283, 460, 476, 505
fluvicola new species,

Spanglerina, 3, 38, 216, 218, 455,

480

fossatus (LeConte),

Gymnochthebius, 7, 20, 38, 248,
274, 276, 277, 279, 280, 281, 284, 388,
431,460, 504
fossatus Leconte,

Ochthebius, 277, 280
foveicollis LeConte,

Ochthebius, 277 , 280

francki (Bruch),

Gymnochthebius, 38, 250, 264
francki Bruch, Ochthebius, 264
frondsicola new species,

Spanglerina, 3,38,216,219,220,
455,480

geminya new species,

Hydraena, 6, 1 2, 38, 69, 206, 207,
209, 454

geminya Subgroup,

Hydraena, 12, 38, 69, 205, 215,

435,450, 454
germaini (Zaitzev),

Gymnochthebius, 29, 38, 250, 256,

257, 258, 261,262, 459, 503
germaini d’Orchymont,

Hydraena, 36,62,67,726,445

germaini Group,

Gymnochthebius, 38, 249, 256,

270

germaini Subgroup,

Gymnochthebius, 38, 249, 256,

459, 460

germaini Zaitzev,

Ochthebius, 256

granulosus Sato,

Ochthebius, 409
granulosus, Neochthebius, 436,471
grouvellei d’Orchymont,

Hydraena, 37,62,71,774,454

gruwelli new species,

Ochthebius, 6, 23, 39, 303, 365,

366, 464, 477,479,518
guadelupensis d’Orchymont,

Hydraena, 37,62,69, 145, 146,

448, 495

guatemala new species,

Hydraena, 6, 19, 37, 70, 7 69

haitensis new species,

Hydraena, 6, 37, 71, 777, 454, 480

hibernus new species,

Ochthebius, 6, 39, 304, 377, 381,

382, 468

holmbergi Maklin,

Ochthebius, 7,318

hyalina new species,

Hydraena, 6,37,69,71,7 79, 454,
497

hygropetrica new species,

Parhydraenida, 3, 36, 45, 49, 56,
57

ingens Group, Spanglerina, 38,216
ingens new species,

Spanglerina, 3,12,38,212,216,
218,372, 455,480
insulanus Brown,

Ochthebius, 7, 295, 377

insularis d’Orchymont,

Hydraena, 14, 37, 62, 71, 183, 497
interruptus Group,

Ochthebius, 23, 38, 299, 306, 435,

462, 463

interruptus LeConte,

Ochthebius, 7, 39, 295, 301, 308,

311, 312, 356, 507
interruptus Subgroup,

Western Hemisphere Hydraenidae

549

Ochthebius, 38, 300, 306, 346,

462, 464, 466
jensenhaarupi (Knisch),

Gymnochthebius, 38, 249, 250,

252, 253, 459
jensenhaarupi Knisch,

Ochthebius, 253, 254
jivaro Complex, Hydraena, 37, 174,
450, 454

jivaro new species,

Hydraena, 6,37,71,1 66, 1 76, 454

kaszabi Janssens,

Ochthebius, 1 4, 39, 30 1 , 306, 3 1 4,
318, 325, 328, 355, 435, 436, 466, 512
laevipennis (LeConte),

Gymnochthebius, 29, 38, 248, 283,

284, 286, 287, 459, 505
laevipennis LeConte,

Ochthebius, 283, 284
laevipennis Subgroup,

Gymnochthebius, 38, 248, 283,

431,455,459
lambda new species,

Parhydraenida, 3,21,36,45,49,

54

lapidicolus Van Dyke,

Ochthebius, 410
lecontei new species,

Ochthebius, 6,39,301, 308, 466,
506

leechi Group, Hydraena, 15, 16, 29,

36, 64, 65, 72, 102, 148, 152, 158, 212,
431, 434, 435, 440, 444, 446, 477
leechi new species,

Hydraena, 7,36,66,67, 103, 115,
494

leechi new species,

Limnebius, 6, 38, 225, 226, 235,
455, 502

leechi Subgroup, Hydraena, 29, 33, 36,
103, 116, 435,444, 445
leechi Wood and Perkins,

Ochthebius, 39, 295, 399, 403,

468, 524

limpidicollis new species,

Hydraena, 7, 37, 70, 167, 168, 169,

454

lindbergi J. Balfour-Browne,

Ochthebius, 20
lineatus LeConte,

Gymnochthebius, 293, 298
lineatus LeConte,

Ochthebius, 20, 245, 295, 300,

314, 315, 318, 352, 365,466, 508
longicollis Sharp, Hydraena, 37, 62,

70, 187, 190, 454, 472, 476, 480, 498
madrensis new species,

Ochthebius, 6, 39, 302, 366, 368,

464.519

malkini new species,

Hydraena, 7, 37, 72, 196
marginicollis Complex,

Hydraena, 37, 184, 437, 446, 450,
454

marginicollis Group,

Hydraena, 15,22,37,63,64,69,
72, 164, 212, 215, 431, 434, 435, 440,
477

marginicollis Kiesenwetter,

Hydraena, 18, 19, 37, 62, 70, 148,
184, 188, 190, 454, 476, 497
marginicollis Subgroup,

Hydraena, 37, 69, 1 64, 169, 172,
182, 190, 193, 196, 198, 199, 435, 450
marinus (Paykull),

Ochthebius, 7,39,298,301,306,
314, 318, 321, 325, 326, 328, 355, 407,
435,436, 466,510
marinus Paykull, Elophorus, 318
martini Fall, Ochthebius, 39, 303, 399,
400, 468, 524
maureenae new species,

Gymnochthebius, 6, 13, 29, 38,

248, 283, 287, 460
maureenae new species,

Hydraena, 7,37,66,136,735,445,
446, 476, 479
mazamitla new species,

Hydraena, 7, 37, 68, 1 1 5, 156, 449
mesoamericanus new

species, Ochthebius, 6, 39, 302,

373.519

Quaest. Ent., 1980, 16 (1,2)

550

Perkins

mexcavatus new species,

Ochthebius, 6, 39, 302, 346, 368 ,
463,464, 479,519
mexicana Complex,

Hydraena, 37, 165 , 437, 450, 452

mexicana new species,

Hydraena, 7, 37, 71, 777, 172, 205,
450, 497

mexicanus new species,

Limnebius, 6, 38, 226, 243, 455
mexicanus new species,

Ochthebius, 6, 39, 298, 304, 394 ,
397,470

mignymixys new species,

Hydraena, 7, 36, 64, 83, 92
milleri Hatch, Ochthebius, 7, 295, 314,
315

mimicus Brown,

Ochthebius, 39,303,377,381,

382, 383, 522
mitus new species,

Limnebius, 6, 38, 226, 238, 455
needhami d’Orchymont,

Hydraena, 7,62,148
nevermanni new species,

Hydraena, 7, 37, 71, 795, 498
newtoni new species,

Hydraena, 7, 37, 70, 168, 454
nigra Hatch, Hydraena, 36, 65, 84, 85,
475, 487

nitiduloides (d’Orchymont),
Gymnochthebius, 7
nitiduloides d’Orchymont,

Ochthebius, 277
nitidus (LeConte),

Gymnochthebius, 38, 274, 276,

279, 280, 281,460, 476, 504
nitidus Group,

Gymnochthebius, 38, 245, 248,

256, 274, 459, 477
nitidus LeConte,

Ochthebius, 274, 276, 280, 295
nitidus Subgroup,

Gymnochthebius, 38, 248, 274,
431,455,459, 460
oaxaca new species,

Hydraena, 7, 37, 68, 752, 449
oblio new species,

Hydraena, 7, 37, 67, 149, 446, 447,
448, 496
obscurus Sharp,

Ochthebius, 39, 112,302 ,372,

464, 519

occidentalis new species,

Hydraena, 7, 36, 65, 78, 444, 485
ocellata Germain,

Hydraenida, 36, 40, 41, 43

octolaevis new species,

Limnebius, 6, 38, 226, 243, 455,
503

octonarius new species,

Gymnochthebius, 6, 38, 249, 250,

252, 253, 254, 459
oppositus new species,

Gymnochthebius, 6, 29, 38, 248,

274, 289, 292, 476
oppositus Subgroup,

Gymnochthebius, 38, 248, 289,

431,455,459
orbus new species,

Ochthebius, 6, 39, 304, 377, 380,
382

orcula new species,

Hydraena, 7, 37, 140, 448
ozapalachicus new species,

Limnebius, 6, 12, 38, 84, 225, 230,
499

ozarkensis new species,

Hydraena, 7, 33, 37, 66, 118, 136,
138,445,446,476, 479, 495
pacifica new species,

Hydraena, 7, 36, 65, 86, 88, 444,

475,488

pacificus new species,

Ochthebius, 6, 38, 301, 306, 308,
313,356, 466, 505
paeminosa Group,

Hydraena, 38, 64, 210, 435, 440

paeminosa new species,

Hydraena, 7,20,38,277,440

paraguayensis Janssens,

Hydraena, 36, 62, 66, 128, 445

Western Hemisphere Hydraenidae

551

paralonga new species,

Parhydraenida, 3,21,36,45,49,
56, 57

particeps Group, Hydraena, 448
particeps new species,

Hydraena, 7, 37, 69, 142, 448, 495
particeps Subgroup,

Hydraena, 37, 140, 437, 446, 480
parvulus (Sharp),

Gymnochthebius, 7
parvulus Sharp, Ochthebius, 277 , 281
pauli new species,

Ochthebius, 6, 39, 302, 368, 464
pavicula new species,

Hydraena, 1,36,66,123

pennsylvanica Complex,

Hydraena, 36, 72, 96, 444, 475

pennsylvanica Kiesenwetter,

Hydraena, 36, 62, 64, 82, 83, 96,

97,427,444, 475,479,491
pentatenkta Group,

Parhydraenida, 36, 59

pentatenkta new species,

Parhydraenida, 3, 13, 36, 48, 49,

59, 434, 439
perkinsi Spangler,

Hydraena, 37, 71, 172, 173, 454,

480

perlabidus new species,

Gymnochthebius, 6, 13, 29, 38,

248, 286, 287

peru new species, Hydraena, 7, 37, 70,
190

peruvianus

(J. Balfour-Browne),
Gymnochthebius, 38, 250, 268

peruvianus

J. Balfour-Browne,

Ochthebius, 268
petila new species,

Hydraena, 7, 36, 65, 91, 444, 477,
490

piceus (Horn), Limnebius, 38, 226,

230, 455, 500

piceus Horn, Limnocharis, 222, 230

plaumanni d’Orchymont,

Hydraena, 37, 62, 67, 129, 445
plesiotypus Group,

Gymnochthebius, 38, 248, 250,

256, 431,459
plesiotypus new species,

Gymnochthebius, 6, 38, 249, 250,

257,254, 430, 459
plesiotypus Subgroup,

Gymnochthebius, 459

polita Casey, Limnocharis, 230
pontequula new species,

Hydraena, 7, 16, 19,37,72, 169,

198, 499

premordica new species,

Hydraena, 7, 37, 70, 775, 454

prieto new species,

Hydraena, 7, 20, 37, 68, 757, 449,
480, 496

pulsatrix new species,

Hydraena, 7, 19, 37, 70, 184, 7 87,
188, 190, 454, 472, 476, 480, 498
punctata LeConte,

Hydraena, 7, 20, 37, 62, 63, 68,

148 , 149, 448,479, 496
puncticollis Group,

Ochthebius, 39, 303, 399, 403,

406, 468

puncticollis LeConte,

Ochthebius, 39, 303, 399, 402,

403, 406, 468, 479, 523
puncticollis Sharp,

Hydraena, 19, 37, 62, 66, 130, 131,
445

putnamensis Blatchley,

Ochthebius , 39, 377, 385, 435,

464, 468, 469
quadraticeps

J. Balfour-Browne,

Parhydraenida, 36, 45, 49, 439
quadricurvipes new species,

Hydraena, 7, 1 5, 36, 64, 72, 93, 94,
444, 491

quechua new species,

Hydraena, 7, 37, 71, 166, 176, 454
recticulus new species,

Ochthebius, 6, 39, 300, 328, 329,

Quaest. Ent., 1980, 16 (1,2)

552

Perkins

332, 465,466,514

rectus LeConte, Ochthebius, 39, 300,
329, 331, 332, 377, 400, 466, 513
rectus Subgroup,

Ochthebius, 39, 300, 328, 462,

464, 465

rectusalsus new species,

Ochthebius, 6, 39, 300, 328, 329,

331,332, 466,513
reichardti Group,

Parhydraenida, 36, 49, 439

reichardti

J. Balfour-Browne,

Parhydraenida, 21,36,45,48,49,

52, 419, 439, 482
reticulatissimus new species,

Gymnochthebius, 6, 38, 249, 250,

273

reticulatus (d’Orchymont),

Gymnochthebius, 38, 249, 250,

271,213

reticulatus d’Orchymont,

Ochthebius, 271

reticulatus Subgroup,

Gymnochthebius, 38, 249, 271

reticulocostus new species,

Ochthebius, 6, 39, 304, 394, 470

reticulocostus Subgroup,

Ochthebius, 39, 304, 376, 391 ,

468, 470, 479
richmondi new species,

Limnebius, 6, 38, 84, 140, 225,

227, 479

richmondi new species,

Ochthebius, 6, 39, 299, 339, 464,

515

riparia Kugelann,

Hydraena, 60

robusta new species,

Hydraenida, 3, 36, 40, 41, 43, 434

sabella new species,

Hydraena, 7, 37, 72, 199, 454, 499

sahlbergi Champion,

Laeliaena, 430

sahlbergi d’Orchymont,

Hydraena, 37, 62, 69, 141, 146

schubarti d’Orchymont,

Ochthebius, 7, 295, 346
scintilla new species,

Hydraena, 7, 36, 65, 67, 111, 153,

372, 445

scintillabella new species,

Hydraena, 7 , 36, 66, 1 18, 475

scintillabella Subgroup,

Hydraena, 29,33,36,775,435,

445, 447

scintillutea new species,

Hydraena, 7,36,66,779

scolops new species,

Hydraena, 7, 37, 68, 153, 449

scopula new species,

Hydraena, 7,36,66,67,103,115,

132, 156, 445
sculptoides new species,

Ochthebius, 6, 39, 302, 346, 351 ,
352,353,356, 392,516
sculptus LeConte,

Ochthebius, 39, 302, 352, 353,
356,517

seminole new species,

Gymnochthebius, 6, 38, 248, 274,
289, 290, 292, 476
sierra new species,

Hydraena, 7,36,65,100,7(97,441,
444, 475, 494

sierrensis new species,

Ochthebius, 6,39,301,313, 466,
507

similis Sharp, Ochthebius, 7, 39, 293,
295,298,385,522
similis Subgroup,

Ochthebius, 39, 304, 385, 468,

469, 479

simplex LeConte,

Ochthebius, 346

sinuatus (Sharp),

Limnebius, 29, 38, 113, 226, 236,
419, 455, 502
sinuatus Sharp,

Limnocharis, 236
sordida Sharp, Hydraena, 37, 62, 67,
129, 130, 445

Western Hemisphere Hydraenidae

553

spangleri new species,

Hydraena, 7, 37, 69, 141, 146, 448,
479, 496

spanglerorum Wood and

Perkins, Ochthebius, 39, 295, 302,
357,359, 464,517
sparsa Sahlberg, Laeliaena, 430
splecoma new species,

Hydraena, 7, 37, 72, 172, 204, 399

sulcicollis Germain,

Ochthebius, 256
tectus new species,

Gymnochthebius, 6, 38, 250, 256,

258, 261,459, 504
terralta new species,

Hydraena, 7, 36, 67, 1 18, 121, 722,

445

texanus new species,

Limnebius, 6,38,226,247,455,

479

topali (J. Balfour-Browne),

Gymnochthebius, 38, 249, 265,

459, 504

topali J. Balfour-Browne,

Ochthebius, 265

trinidensis Complex,

Hydraena, 37 ,180,450,454

trinidensis new species,

Hydraena, 7, 37,71, 7 82, 450, 454

tuberculatus LeConte,

Ochthebius, 277 , 280

tubus new species,

Ochthebius, 6, 23, 29, 39, 302,

352, 353, 355, 356, 419, 427, 464, 517

tucumanica new species,

Hydraena, 7, 37, 70, 165, 454
tuolumne new species,

Hydraena, 7, 36, 65, 79, 444, 486
turrialba new species,

Hydraena, 7, 37, 70, 186
uniformis new species,

Ochthebius, 6,39,300,314,327,
355,436, 466,511
utahensis new species,

Limnebius, 6, 38, 225, 236, 455
vandykei (Knisch),

Neochthebius, 20, 39, 331, 409,
410, 436, 471,524
vandykei d’Orchymont,

Hydraena, 36, 62, 65, 75, 100, 101,
102, 444, 475,493
vandykei Knisch,

Ochthebius, 408,409,410
vandykei niger Hatch,

Hydraena, 62, 84

vectis new species,

Meropathus, 6, 13, 17, 29, 39, 407,
434, 471

vela new species, Hydraena, 7, 38, 69,
206

wickhami Fall, Ochthebius, 7, 295,

385

yosemitensis new species,

Hydraena, 7, 36, 65, 94, 444

youngi new species,

Hydraena, 7,37,67,750,448

zapatina new species,

Hydraena, 7, 37, 67, 118, 131, 445

Quaest. Ent., 1980, 16 (1,2)

554

Perkins

KEYS

Key to Genera of Western Hemisphere Hydraenidae, p. 34
Key to Species of Western Hemisphere Parhydraenida, p. 49
Key to Groups of Western Hemisphere Hydraena, p. 64
Key to Species of circulata Group, Hydraena, p. 64
Key to Species of leechi Group, Hydraena, p. 65
Key to Species of marginicollis Group, Hydraena , p. 69
Key to Species of Western Hemisphere Spanglerina, p. 216
Key to Species of Western Hemisphere Limnebius, p. 225
Key to Species of Western Hemisphere Gymnochthebius, p. 248
Key to Subgenera of Western Hemisphere Ochthebius, p. 298
Key to Species of Western Hemisphere Ochthebius ( sensu stricto ), p. 299
Key to Species of Western Hemisphere Ochthebius (Asiobates), p. 303

Publication of Quaestiones Entomologicae was started in 1965 as part of a
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Department of Entomology
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T6G 2E3

Quae st

lones

Entomologicae

A periodical record of entomological investigations*
published at the Department of Entomology,
University of Alberta, Edmonton, Canada.

VOLUME 16

NUMBERS 3-4

JULY-OCTOBER 1980

QUAESTIONES ENTOMOLOGICAE

ISSN 0033-5037

A periodical record of entomological investigation published at the Department of
Entomology, University of Alberta, Edmonton, Alberta.

Volume 16

Numbers 3,4

July-October 1981

CONTENTS

Pike - Origin of tundra butterflies in Alberta 555

Halffter, Halffter and Huerta - Mating and nesting behavior of Eurysternus (Coleoptera:

Scarabaeinae) 597

Smith and Lehmkuhl - The larvae of four Hydropsyche species with the checkerboard head

pattern (Trichoptera: Hydropsychidae) 621

Smith and Lehmkuhl - Analysis of two problematic North American caddisfly species: Oecetis

avara (Banks) and Oecetis disjuncta (Banks) (Trichoptera: Leptoceridae) 635

Donald and Mutch - The effect of Hydroelectric dams and sewage on the distribution of

stoneflies (Plecoptera) along the Bow River 657

Smith - Sawflies (Hymenoptera: symphyta) from George Lake, Alberta 671

Book Review-Griffiths, G.C.D. 1980. Flies of the Nearctic Region 676

Book Review-Howden, H.F. and O.P. Young. 1981. Panamanian Scarabaeinae:Taxonomy,

distribution and habits (Coleoptera, Scarabaeidae) 678

Book Review-Reigert, P.W. 1980. From arsenic to DDT: A history of entomology in western

Canada 679

Book Review-Matthews, E.G. 1980. A guide to the genera of beetles of South Australia. Part

1 681

Editor’s acknowldgements 683

Index 685

ORIGIN OF TUNDRA BUTTERFLIES IN ALBERTA

E.M.Pike'

Department of Entomology
University of Alberta

Edmonton, Alberta Quaestiones Entomologicae

16:555-596 1980

ABSTRACT

Four distribution types are recognized in the tundra butterfly fauna of Alberta. These
indicate two source areas. The major source area was south of Wisconsin ice in northern
Washington, Idaho, and Montana. Nine taxa survived in this unglaciated area, five with a
Southern Montane distribution: Lycaena phlaeas arethusa ( Wolley-Dod 1907), Lycaena snowi
snowi (Edwards, 1881), Oeneis polixenes brucei ( Edwards , 1891), Oeneis bore edwardsi dos
Passos, 1949, and Oeneis melissa beani Elwes, 1893. The remaining four have a Central
Montane distribution: Colias nastes streckeri Grim-Grschimaillo, 1895, Boloria astarte
(Doubleday, 1846-1852(1847 )), Boloria alberta (Edwards, Edwards 1890) Euphydryas editha
beani Skinner, 1897. This refugium was restricted on the north by the presence of ice, and on
the other three sides by lack of suitable habitat, indicating a narrow and discontinuous tundra
belt south of Wisconsin ice. With retreat of Wisconsin ice, dispersal north was stopped by the
elimination of continuous tundra in mountain valleys.

Taxa with disjunct populations or endemic forms survived glaciations in an Albertan
refugium in the vicinity of Mountain Park. The Albertan refugium did not contribute
significantly to the colonization of present day Alberta tundra. Disjunct distribution is shown
by Boloria improba youngi (Holland, 1900). Endemic forms are Boloria eunomia nichollae
(Barnes and Benjamin, 1926), Boloria napaea reiffi Reuss, 1925, and an ecological form of
Oeneis melissa beani Elwes, 1893.

This investigation yielded information on two isolated refugia. Therefore, the study of
butterfly distribution patterns is deemed of great potential value in the study of Wisconsin
glacial refugia in general.

On reconnait quatre types de distribution parmi la faune albertaine des papillons diurnes de la toundra. Ces types
indiquent qu’il existe deux regions d’origine pour ces papillons. La principale est situee sud de la calotte glaciaire du
Wisconsin dans le nord des etats de Washington, de I’Idaho et du Montana. Dans cette region, qui echappa a la
glaciation, neuf taxons ont survecu, dont cinq sont distribues dans I’etage montagnard sud; ce sont: Lycaena phlaeas
arethusa (Wolley-Dod, 1907), Lycaena snowi snowi (Edwards, 1881), Oeneis polixenes brucei (Edwards, 1891), Oeneis
bore edwardsi dos Passos, 1949, et Oeneis melissa beani Elwes, 1893. Les quatre autres taxons occupent I’etage
montagnard central; ce sont: Colias nastes streckeri Grum-Grschimaillo, 1895, Boloria astarte (Doubleday 1846-1852
(1847)), Boloria alberta (Edwards, 1890) et Euphydryas editha beani Skinner, 1897 . Cette zone refuge etait limitee au
nord par la calotte glaciaire, et sur ses trois autres cotes, par /’ absence d'habitats propices, indiquant que la ceinture de
toundra etait etroite et discontinue au sud de la calotte glaciaire du Wisconsin. Avec le retrait de la calotte, la dispersion
vers le nord fut interrompue par I’elimination des zones continues de toundra dans les vallees de montagne.

1 Present address: Box 1231, Fairview, Alberta, TOH 1L0

556

Pike

Des taxons a populations disjointes ou des formes endemiques ont survecu aux glaciations dans un refuge
albertain situe pres de Mountain Park. Ce refuge ne contribua pas de facon significative a la colonisation de la
toundra albertaine actuelle. Une distribution disjointe apparait chez Boloria improba youngi (Holland. 1900). Les
formes endemiques sont representees par Boloria eunomia nichollae (Barnes et Benjamin, 1926), Boloria napaea reiffi
Reuss, 1925, et par une variete eologique d’ Oeneis melissa beani Elwes, 1893.

Cette recherche fournit de I’information sur deux refuges isoles. Par consequent, I’etude des patrons de
distribution des papillons est consideree comme ayant une grande valeur potentielle dans I’etude des refuges de la
periode glaciaire Wisconsin.

TABLE OF CONTENTS

Introduction 556

Materials and Methods 557

Results 558

Discussion 568

Conclusions 574

Acknowledgements 574

References 574

Figures 580

INTRODUCTION

Certain butterfly taxa have long been recognized as having relict distributions which reflect
Pleistocene events (Grote, 1875; Maynard, 1886; Holland, 1898). In spite of the early
recognition of these relict taxa, few subsequent workers have considered butterflies in studies of
suspected refugia in North America.

Yet butterflies would seem to be subjects well suited to such studies for two reasons. In
terms of numbers of species, butterflies form an important part of the tundra community.
There are more species of butterflies on the arctic islands than there are of the order Coleoptera
(Ryan, 1977). This indicates a high probability that they might survive the conditions of a
tundra refugium. A second reason is that butterflies appear to differentiate more rapidly than
many other insect taxa (Ford, 1946). This suggests that butterfly taxa surviving in a small
refugium might develop endemic tendencies to a greater extent than other insects.

A number of tundra refugia of this type have been suggested in North America, but few
have escaped criticism. One that has, is in the area of Mountain Park, Alberta, Canada (see
figure 1). This area is easily accessable and so became the focal area of this study.

The objectives of this paper were to determine the value of the distributions of Alberta s
tundra butterflies to the study of Wisconsin age refugia. This entails the location of source
areas, routes of immigration, and barriers to dispersal. In order to meet this objective, detailed
distribution maps of all North American were compiled.

Tundra butterflies in Alberta

557

MATERIALS AND METHODS

Materials

During the course of this study, 1124 specimens were collected in Alberta and British
Columbia, of which 907 represent taxa known to occur in Alberta. A further 720 specimens
were examined from private collections, making a total of 1844 specimens.

Specimens collected within the boundaries of Banff and Jasper National Parks are deposited
in the Canadian National Collection, Ottawa, Ontario; University of Alberta Strickland
Museum, Edmonton, Alberta; and Park offices in Banff and Jasper. Remaining specimens are
deposited as follows: voucher specimens to the University of Alberta Strickland Museum, and
selected series to my collection. Some material was exchanged for specimens for future
research.

Methods

A tundra butterfly species is a taxon in which the life cycle is confined to areas above
treeline. This definition includes both arctic and alpine taxa. The existence of tundra is usually
defined through reference to treeline. Treeline is here used to delineate the lower, or southern,
boundary of the subarctic or subalpine zone as defined by Love (1970). This is necessitated by
the occurence of tundra butterfly taxa south of the actual limit of trees.

Because of limited dispersal abilities of most species used as ndicators of refugia, and the
island nature of alpine tundra, taxa restricted to tundra provide the best biological evidence for
identifying sites of suspected alpine refugia.

Because this study is not a revision, subspecies were accepted as presented in dos Passes
(1964), as modified by more recently published information. None of these subspecies has been
adequately investigated. Although many may not be valid taxonomically, the names provide
convenient sources of reference to recognizably distinct populations. This is the sole reason for
their use in this study. Most subspecies of in Alberta are fairly distinct, and are readily placed
with populations outside the province. This allows reasonably secure hypotheses about their
evolution and dispersal into Alberta.

Study area

The area under study includes all known tundra examined for butterflies in North America,
but the focus of attention is on tundra in Alberta. Tundra extends from the Sierra Nevada of
California and the Sangre de Cristo range of New Mexico (approximately 36° N.) at elevations
of over 3384 meters (1 1,000 ft.), north to the limit of land on Ellesmere Island and Greenland
(approximately 83° N.). In eastern North America, isolated areas of tundra occur as far south
as Mount Marcy, New York, and Mount Washington, New Hampshire (approximately 44°
N.) at elevations of just over 1358 meters (5000 ft.).

In Alberta, tundra extends from the United States border (49° N.) north to about 56° 20
N., where the Rocky Mountains are extended west of the provincial boundary, province.
Occurrence of tundra roughly parallels the Alberta-British Columbia border along the
continental divide. It is usually above 1970 meters (6500 ft.) in northern areas of the province,
gradually increasing in elevation to the point where it is not found below 2153 meters (7000 ft.)
at 49° N.

Quaest. Ent., 1980, 16(3,4)

558

Pike

Results

The following tundra butterfly taxa have been reported from North America.

Where possible, sequence and classification follow dos Passos (1964). Numbers preceding
names refer to this ordering. Changes reflect recent descriptions or instances where status of
taxa have been questioned. Asterisks preceding a name indicates that the taxon has been
recorded from Alberta.

243 Parnassiius eversmanni thor H. Edwards, 1881
Type-locality; upper reaches of the Yukon River.

Geographical Distribution. - Known distribution is given in Figure 2. This species is also
recorded from arctic Europe and Asia, southward on numerous mountain ranges, with one
disjunct population in Japan. In North America, this subspecies has dispersed outside of
Beringia only to adjacent mountain ranges in British Columbia, where it is represented by two
populations whose ranges are disjunct from one another.

Material examined: 88 specimens.

285 Colias boothii Curtis, 1835

Type-locality: Boothia peninsula, North West Territories.

Notes. -

Adults of this species have been confused by taxonomists in the past with those of C. nastes
and C. hecla, and the species was once thought to represent a hybrid of these taxa. It is now
recognized as a distinct species, but some taxonomists still confuse specimens with those of
yellow populations of C. nastes , particularly C. n. thula (Philip, in The Lepidopterists’ Society
season Summaries, 1974, 1975, 1976). Populations of C. n. thula are sympatric with those of C.
n. aliaska. This indicates three possibilities: C. n. thula is a spcies distinct from both C. boothii
and C. nastes; C. n. thula is an Alaskan subspecies of C. boothii’, C. n. thula is a form of C.
nastes not deserving taxonomic recognition. Because neither C. n. thula or C. boothii are found
in Alberta, this problem does not affect the outcome of this project.

Geographical Distribution.

Distribution is indicated in Figure 3, along with that of C. n. thula which is plotted here to
show that the two are allopatric. C. n. thula is restricted to northern Alaska, C. boothii to the
North West Territories and the Yukon Territory.

Material examined: 2 specimens.

296 Colias nastes Boisduval, 1832
Seven subspecies are currently recognized.

C. n. nastes Boisduval, 1932
Type-locality: Labrador (Ungava Peninsula).

C. n. rossi Guenee, 1864

Type-locality: Boothia Peninsula, North West Territories.

C. n. moina Strecker, 1880
Type-locality: Churchill, Manitoba.

* C. n. streckeri Grum-Grschimailo, 1895
Type-locality: Laggan, Alberta (Lake Louise).

C. n. cocandicides Verity, 1911
Type-locality: unavailable.

Tundra butterflies in Alberta

559

C. n. thula Hovanitz,

Type-locality: Meade River, Alaska.

C. n. aliaska Bang-Haas, 1927
Type-locality: unavailable
Notes. -

C. n. streckeri includes only green colormorphs, which exhibit slight, but constant variation.
Adults were first collected on a number of mountains in the vicinity of Laggan, Alberta, by T.
E. Bean. It has since been reported from many mountains in Alberta. Colonies probably exist in
the province wherever tundra has developed. Specimens are usually abundant, although often
difficult to catch. Populations from Pink Mountain, British Columbia, are provisionally
assigned to this subspecies.

This species has not been adequately treated in a revision. If it were, it is probable that some
of the presently accepted names would be synonymized.

Geographical Distribution. -

Distribution is shown in Figures 3 and 4. This species is also known from Europe and Asia.
In North America, it is recorded from Alaska, Yukon and North West Territories, Quebec,
Manitoba, Labrador, British Columbia, Alberta, Washington, and Montana. Alberta
distribution is indicated in Figure 24.

Exact limits of the subspecies are not known in the arctic, although the range shown on the
map is probably close to the actual range of the species.

Material examined: 271 specimens.

443 Lycaena phleas Linnaeus(Linnaeus, 1761)

Four subspecies are recognized, only three of which are restricted to tundra habitat.

L. p. hypophleas Boisduval, 1852)

Type-locality: Sierra of California.

*L. p. arethusa (Wolley-Dod, 1907)

Type-locality: Sheep River, 30 miles south west of Calgary, Alberta.

L. p.feildeni (M’Lachlan, 1878)

Type-locality: Ellesmere Island, 81° 41 N., North West Territories.

Notes. -

The distribution patterns and relationships between the various subspecies in Europe and
North America are poorly understood. In North America, one subspecies, L.p.
americanaLycaena phleas americana, does not occur on tundra. Also, while L. p. arethusa
specimens are encountered most often above treeline, some range well below treeline in Alberta.
The type locality, if taken literally, is well below treeline, although Wolley-Dod may have been
referring to the headwaters of the River, which are much higher in elevation. Specimens have
been taken below treeline more regularly at Mountain Park, and northwards on Prospect
Mountain, and at Moberly Creek, and Grande Cache. In spite of intensive collecting in recent
years, specimens have not been found below treeline south of Mountain Park. For this reason,
boreo-montane populations are here considered to be derived from alpine populations, and this
subspecies is considered a tundra butterfly. It is also possible that the low altitude populations
represent a distinct taxon separate from the alpine populations.

Geographical Distribution. -

L. p. arethusa is found as far south as Colorado, and as far north as Grande Cache, Alberta.
The nominotypical form is European. This species is found over much of Europe and Asia. The

Quaest. Ent., 1980, 16(3,4)

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Pike

Nearctic distribution is indicated in Figure 5. Alberta distribution is indicated in Figure 25.
Material examined: 33 specimens.

445 Lyceana snowi (Edwards, 1881)

Two subspecies are recognized.

* L. s. snowi (Edwards, 1881)

Type-locality: Colorado.

L. s. henry ae (Cadbury, 1937)

Type-locality: Cariboo Pass, Peace River Country, British Columbia.

Notes. -

L. s. henryae has not been collected since its description. L. s. snowi was first collected in
Alberta by T. E. Bean in the vicinity of Laggan. However, specimens -are more commonly
encountered to the south than to the north in the province. In Alberta, it appears to be
restricted to above treeline, but in Wyoming, it has been reported below treeline (Howe, 1975;
Ferris, 1971).

Opinions differ about the relationship of this species to L. cupreus, whose range is below
treeline in California, north east to Colorado. Howe (1975) and Ehrlich and Ehrlich (1961)
consider the two groups conspecific. Dos Passos and most previous authors consider them
distinct. I follow dos Passos. Certainly the two taxa are closely related. However, this
taxonomic problem does not affect the outcome of this project because the Alberta material is
clearly similar to L. snowi of Colorado.

Geographical Distribution. -

Distribution is indicated in Figure 6. L. snowi is found from Colorado north to central
British Columbia. It has not been reported from the Yukon Territory or Alaska. Alberta
distribution is indicated in Figure 26.

Material examined: 25 specimens.

595 Euphydryas edit ha (Boisduval, 1852)

Eighteen subspecies are currently recognized. Of these, only four are restricted to tundra.
These are treated below.

E. e. nubigena Behr, 1863

Type-locality: Headwaters of the Tuolumne River and beyond to elevations of 11500 ft. (3538
m.), California.

E. e. lawrenci Gunder, 1931

Type-locality: Mount Theilsen, Douglas County, Oregon.

E. e. colonia Write, 1905
Type-locality: Mt. Hood, Oregon.

*E. e. beani Skinner, 1897

Type-locality: High elevations near Laggan, Alberta (Lake Louise).

Notes. -

While most subspecies of E. editha are not found on tundra, these four subspecies appear to
be restricted to tundra environments, which they evidently colonized recently, apparently in
response to empty niches on the mountains they inhabit. With the exception of E. e. beani , they
occur where there are virtually no other tundra butterflies.

E. e. beani has been reported more commonly to the south of the type locality, where
specimens were collected by T. E. Bean. Specimens are easily confused with alpine specimens

Tundra butterflies in Alberta

561

of E. anicia. The northern records of E. e. beani are older, and may represent
misidentifications, but most of the southern records have been verified in recent years.
Geographical Distribution. -

Distributions are indicated in Figure 7. E. e. beani is restricted to the mountains of southern
Alberta and British Columbia and E. e. nubigena is restricted to the high Sierras of California.
The other two subspecies have only been recorded from their type localities. Alberta
distribution is indicated in Figure 27.

Material examined: 27 specimens.

597 Boloria napaca (Hoffmansegg, 1804)

The nominotypical form is European. Four subspecies have been recorded from North
America.

B. n. alaskensis (Holland, 1900)

Type-locality: Mountains between 40 mile and Mission Creeks, Alaska.

B. n. nearctica Verity, 1932
Type-locality: North eastern Alaska.

*B. n. reiffi Reuss, 1925

Type locality: Mountains of British Columbia.

B. n. halli Klots, 1940

Type-locality: Green River Pass, Wind River Mountains, Wyoming.

Notes. -

Shepard (in Howe, 1975) has made B. n. reiffi a junior synonym of B. n. alaskensis . This is
without warrant, for it is not based on study of the type specimen, but rather on conjecture by
Klots (1940) and Warren (1944). Specimens of B. n. reiffi have been recorded from Kvass
Creek Summit and the headwaters of the Berland River, Alberta. I adopt this assignment
because of the proximity of the type locality.

In the past, these subspecies were treated under the name B. pales (Denis and
Schiffermuller, 1775). Warren(1944) placed them under the name B. napaea. This is generally
accepted, but it is based on characters of doubtful significance.

Geographical Distribution. -

Distribution is indicated in Figure 8. This species is common in arctic and alpine areas of
Europe and Asia. In North America, it is found in Alaska, Yukon Territory, and arctic North
West Territories excluding the northern-most arctic islands. It has been reported in northern
British Columbia, and as disjunct populations in central Alberta, and in Wyoming. Alberta
distribution is indicated in Figure 28.

Material examined: 78 specimens.

601 Boloria improba ( Butler , 1877)

Two subspecies are recognized.

B. i. improba (Butler, 1877)

Type-locality: Winter Cove, Cambridge Bay, North West Territories.

*B. i.youngi (Holland, 1900)

Type-locality: Mountains between 40 mile and Mission Creeks, Alaska.

Notes. -

B. improba was first reported from Alberta in 1976 from Prospect Mountain (see Figure 1).
Eleven specimens have been collected. Adults of this population appear most similar to those of

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Pike

B. i. youngi, and the Alberta population is so placed, but it may deserve subspecific status.
Adults show constant and remarkably stable differences from adults of other examined
populations. This is a highly variable species year to year, so longer series are needed before a
decision can be made. In the summer of 1978, another disjunct population was discovered in
Colorado (Sperling, pers. comm.)

This population has been described as B. acrocnema Gall and Sperling, 1980.

Geographical Distribution. -

Distributions of the two subspecies are indicated in Figure 9. This species is also known from
arctic Europe and Asia. In North America, it is found in Alaska, the Yukon Territory, arctic
North West Territories excluding the high arctic islands, northern British Columbia, and
disjunct populations in west-central Alberta and Colorado. Alberta distribution is indicated in
Figure 29.

Material examined 147 specimens.

604 Boloria polaris (Boisduval, 1829)

Three subspecies are recognized.

B. p. polaris (Boisduval, 1829)

Type-locality: Norwegian Alps.

B. p. groenlandica (Skinner, 1892)

Type-locality: Greenland.

B p. stellata Masters, 1972
Type-locality: Churchill, Manitoba.

Notes. -

Adults of this species are rarely collected, although they are often abundant. Unlike most
butterfly species, very few infraspecific names have been proposed for this taxon.

Geographical Distribution. -

This species is found from Lappland across arctic Europe and Asia to Greenland. In North
America, it is recorded from Alaska, Yukon Territory, North West Territories including the
high arctic islands, Manitoba, Quebec, Labrador, and northern British Columbia. Distribution
is indicated in Figure 10.

Material examined: 234 specimens.

606 * Boloria alberta (Edwards, 1890)

Type-locality: Laggan, Alberta (Lake Louise).

Notes. -

This species has been reported from Anaktuvuk Pass, Alaska, but because worn adults of B.
polaris and B. distincta resemble those of B. alberta , this record must be regarded as suspect.
Geographical Distribution. -

This species is restricted to high alpine areas in northern Montana, southern Alberta and
British Columbia. A different subspecies has been reported from the U.S.S.R. Nearctic
distribution is indicated in Figure 12. Alberta distribution is indicated in Figure 30.

Material examined: 43 specimens.

607 * Boloria astarte (Doubleday, 1846-1852(1847))

Type-locality: Mountains of British Columbia, here restricted to Mt. Cheam.

Tundra butterflies in Alberta

563

Notes. -

dos Passos (1964) and Shepard (in Howe, 1975) recognize two subspecies; B. a. astarte and
B. a. distincta. Wyatt (1957) discounts the hypothesis that they are conspecific. Because of
numerous differences between the two taxa, I follow Wyatt. Certainly they are easily
separated, but closely related. The problem does not affect the outcome of this project.

Type-locality is the mountains of British Columbia. (Edwards 1891) roposed the name
which he later recognized as a junior synonym of B. astarte. The type locality for A. victoria is
Laggan, Alberta (Lake Louise).

At the time of the description of B. astarte , British Columbia s boundaries were poorly
defined or non-existent, and the area around Laggan was unexplored. It seems reasonable to
restrict the type locality of B. astarte to the locality nearest the major cities of British Columbia
around 1800-1820. The type-locality is hereby restricted to Mount Cheam, south of Hope,
British Columbia, where lives the population closes to Vancouver Island and the mouth of the
Frazer River.

Geographical Distribution. -

Distribution is indicated in Figure 12. This species is recorded from British Columbia,
Alberta, and northern Washington and Montana. Alberta distribution is indicated in Figure 34.
Material examined: 60 specimens.

607b Boloria distincta (Gibson, 1920)

Type-locality: Harrington Creek, Yukon Territory.

Geographical Distribution. -

In North America this species appears to be restricted to Beringia with one record from
Atlin, British Columbia and a few from the Richardson Mountains, North West Territories.
Distribution is indicated in Figure 13.

Material examined: 15 specimens.

610 Boloria eunomia (Esper, 1787)

Seven subspecies are recognized in North America, four of which are restricted to tundra
(includes alpine bogs) conditions above treeline.

B. e. caelestis ( Hemming, 1933)

Type-locality: Hall Valley, Park County, Colorado.

B. e. ursadentis Ferris and Groothuis, 1971
Type-locality: Beartooth Plateau, Wyoming.

*B. e. nichollae (Barnes and Benjamin, 1926)

Type-locality: Rocky Mountains of North America, here restricted to the north end of Wilcox
Pass, Columbia ice fields, Jasper National Park, Alberta.

B. e. laddi (Klots, 1940)

Type-locality: Lewis Lake, Albany County, Wyoming.

Notes. -

B. e. nichollae was misidentified by Shepard (in Howe, 1975). His identification was based
on the fact that according to the published itinerary of the original collector s trip west
(Nicholls, 1905), she did not and could not have collected in the area where a dark form
corresponding to the description is found. However, she made a later trip west, as indicated by
records of B. alberta and B. astarte collected by her at the headwaters of the Saskatchewan and
Athabasca Rivers, Alberta (Entomological Society of Ontario, records; seasonal collection list,

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564

Pike

1907). This area is the center of the distribution of the dark form of B. eunomia. This suggests
that Mrs. Nicholls could have collected the type series during her second trip. This is supported
by a paratype from the USNM which is darker than normal adults from most areas in the
mountains of Alberta. Accordingly, the type locality is restricted to the north end of Wilcox
pass, Columbia Ice Fields, Jasper National Park, Alberta. This pass was chosen because before
the highway was built between Jasper and Lake Louise, the only way to cross from the
Athabasca watershed to that of the Saskatchewan River was via this pass by pack train (J.
Pike, pers. comm.). If Mrs. Nicholls collected in both watersheds, she must have used this pass,
and probably collected there as evidenced by the type series of B. e. nichollae.

Geographical Distribution. -

Distributions of the four subspecies are indicated in Figure 14. B. e. nichollae is restricted to
west-central Alberta, B. e. ursadentis to its type-locality (Beartooth Plateau, Wyoming), B. e.
laddi to Wyoming, and B. e. caelestis to Colorado. There has been one record of B. e. laddi
from Colorado, but this has been questioned. Alberta distribution is indicated in Figure 32.
Material examined: 184 specimens.

667 Oeneis bore (Schneider, 1792)

Included here is O. taygete Geyer, 1830. Six subspecies are recognized.

O. b. taygete Geyer, 1830
Type-locality: Hopedale, Labrador.

O. b. gaspeensis dos Passos, 1 949
Type-locality: Mount Albert, Quebec.

O. b.fordi dos Passos, 1949

Type-locality: Kuskoquim River Valley, Alaska.

*0. b. edwardsi dos Passos, 1949

Type-locality: San Juan Mountains, Hinsdale County, Colorado.

O. b. hanburyi Watkins, 1928 .

Type-locality: Coronation Gulf, North West Territories.

O. b. mackinleyensis dos Passos, 1 949
Type-locality: Mount McKinley National Park, Alaska.

Notes. -

Adults of these subspecies are very similar to one another. Alberta material was ascribed to
O. b. edwardsi by dos Passos in his description. Adults were first collected in the province at
Nordegg by K. Bowman.

Adults of what is usually considered O. taygete are distinguished by the presence of white
outlined veins on the ventral hind wings. This character does not appear to be constant. Because
of this, and the amount of confusion surrounding the use of these names in the literature, they
are here treated as synonyms to facilitate the handling of locality data. Either way, the outcome
of this project is not affected.

Geographical Distribution. -

Distribution is indicated in Figure 15. This species is found in Alaska, Yukon Territory,
arctic North West Territories excluding the high arctic islands, Quebec, Manitoba, Labrador,
northern British Columbia, Alberta, Montana, Wyoming, and Colorado. There is one record
from Utah. It is also known from Europe and Asia, along the coast of the Arctic Ocean.
Alberta distribution is indicated in Figure 32.

Tundra butterflies in Alberta

565

Material examined: 178 specimens.

670 Oeneis melissa (Fabricius, 1775)

Seven subspecies are recognized.

O. m. melissa (Fabricius, 1775)

Type-locality: Newfoundland.

O. m. semplei Holland, 1931

Type-locality: Little Cape James River; Churchill, Manitoba; Hudson Bay.

O. m. assimilis Butler, 1868

Type-locality: Repulse Bay, North West Territories.

O. m. gibsoni Holland, 1931

Type-locality: Kuskoquim River Valley, Alaska.

O. m. lucilla Barnes and McDunnogh, 1918
Type-locality: Hall Valley, Colorado.

*0. m. beani Elwes, 1893

Type-locality: Laggan, Alberta (Lake Louise).

O. m. semidea (Say, 1828)

Type-locality: White Mountains, New Hampshire.

Notes. -

North of the type-locality, specimens of O. m. beani , while appearing phenotypically
identical to southern specimens, live in a different habitat. Southern populations are restricted
to areas of rock covered by black lichens. In the north, they are found on stable talus slopes
where there is no black lichen.

Distributions of the seven subspecies are indicated in Figure 16. Geographical limits of the
arctic subspecies are uncertain. This species is recorded from Alaska, the Yukon Territory,
arctic North West Territories excluding the high arctic islands, Quebec, Manitoba, Labrador,
Newfoundland, British Columbia, Alberta, Montana, Wyoming, Utah, Colorado, New Mexico,
and New Hampshire. Alberta distribution is indicated in Figure 34.

Material examined: 99 specimens.

671 Oeneis polixenes (Fabricius, 1775)

Six subspecies are recognized.

O. p. polixenes (Fabricius, 1775)

Type-locality: Labrador? America Boreali
O.p. subhyalina (Curtis, 1835)

Type-locality: Boothia Peninsula, North West Territories.

O. p.katahdin (Newcomb, 1901)

Type-locality: Mount Katahdin, Maine.

O. p. peartiae (Edwards, 1897)

Type-locality: Winter Cove, Cambridge Bay, North West Territories.

*0. p. brucei (Edwards, 1891)

Type-locality: Bullion Mountain, Hall Valley, Park County, Colorado.

O. p. yukonensis Gibson, 1920
Type-locality: unavailable.

Notes. -

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Pike

There appears to be a gap in the distribution of O. p. brucei. It is not reported from Montana
or southern Alberta. O. b. edwardsi shows a similar gap. These two species are very similar, and
in both, adults fly early in the season. It is possible that this gap represents a temporal
collecting bias, and not an actual disjunction.

O. p. brucei was first collected in Alberta in the vicinity of Banff. Adults are more
commonly encountered north of Banff than south. This species has not been reported from
southern British Columbia, being restricted, like O. b. edwardsi , to the front ranges east of the
Rocky Mountain Trench.

Geographical Distribution.

Distribution is indicated in Figure 17. This species has been reported from Alaska, the
Yukon Territory, arctic North West Territories excluding the high arctic islands, Quebec,
Manitoba, Labrador, northern British Columbia, Alberta, Wyoming, Colorado, and Maine.
Alberta distribution is indicated in Figure 35.

Material examined: 283 specimens.

675 Erebia magdalena Strecker, 1880
Two subspecies are recognized.

E. m. magdalena Strecker, 1880

Type-locality: Mountains near Georgetown, Colorado.

E. m. mackinleyensis Gunder, 1932

Type-locality: Sable Pass, Mount McKinley National Park, Alaska.

Notes. -

In spite of intensive collecting, this species has not been reported from north of the
Beartooth Plateau, Montana, or south of the Yukon Territory. The two subspecies are fairly
distinct.

Geographical Distribution. -

Distribution is indicated in Figure 18. This species is known from Alaska, the Yukon
Territory, Montana, Wyoming, Utah, Colorado, and New Mexico.

Material examined: 25 specimens.

676 Erebia fasciata Butler, 1868
Two subspecies are recognized
E.f. fasciata Butler, 1868

Type-locality: Victoria Island, North West Territories.

E.f. avinoffi Holland, 1930
Type-locality: Kotzebue Sound, Alaska.

Geographical Distribution. -

Neartic distribution is indicated in Figure 19. This species is known from Alaska, the Yukon
Territory, and arctic North West Territories excluding the high arctic islands and Baffin
Island. It is also recorded from Asia.

Material examined: 25 specimens.

677 Erebia youngi Holland, 1900
Three subspecies are recognized.

E. y. youngi Holland, 1900

Type-locality: Mountains between 40 mile and Mission Creeks, Alaska.

Tundra butterflies in Alberta

567

E.y. herscheli Leussler, 1935

Type-locality: Herscheli Island, Yukon Territory.

E.y. rileyi dos Passos, 1947

Type-locality: Mount McKinley National Park, Alaska.

Notes. -

Adults of this species are easily confused with those of E. dabanensis; records of one may
easily refer to the other.

Geographical Distribution. -

Distribution is indicated in Figure 20. This species is also recorded from Asia. In North
America, it is found in Alaska, the Yukon Territory and western-most arctic North West
Territories.

Material examined: 12 specimens.

Erebia dabanensis Erschoff, 1871
Type-locality: Chamar-daban, Urkutsk, U.S.S.R.

Notes. -

This species has tentatively been identified from a number of localities in Alaska. The
specimens may represent E. youngi. Details for their separation are given in Warren (1936).
Geographical Distribution. -

Distribution is indicated in Figure 21. So far, this species has only been reported from
Alaska and eastern Asia.

Material examined: 1 specimen.

Erebia inuitica Wyatt, 1966
Type-locality: Anaktuvuk Pass, Alaska.

Notes. -

This species has not been collected since its description.

Geographical Distribution. -

The type-locality is indicated in Figure 22.

681 Erebia callias Edwards ,1871
Type-locality: Colorado.

Notes. -

E. callias is common in the southern Rocky Mountains. It is the only endemic butterfly in
the southern Rocky Mountains that is restricted to tundra.

Geographical Distribution. -

Distribution is indicated in Figure 23. It is recorded from Montana, Wyoming, Utah, and
Colorado. It has also been reported from Asia.

Material examined: 23 specimens.

Twelve taxa are known from Alberta. Their distributions are shown in Figures 24 through
35. These taxa are:

C. n. streckeri Figure 24
L. p. arethusa Figure 25
L. s. snowi Figure 26
E. e. beani Figure 27
B. n. reiffi Figure 28

B. alberta Figure 30
B. astarte Figure 3 1
B. e. nichollae Figure 32
O. b. edwardsi Figure 33
O. m. beani Figure 34

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Pike

B. i. youngi Figure 29 O. p. brucei Figure 35

These twelve taxa are grouped into four types of distribution patterns: Southern Montane,
Central Montane, Disjuncts, and Endemics.

TYPE 1 - Southern Montane (Figure 36a)

This pattern includes five taxa whose ranges extend from Alberta south to the
Montana-Wyoming border, or beyond to Colorado and New Mexico.

L. p. arethusa O. b. edwardsi

O. p. brucei O. m. beani

L. s. snowi

TYPE 2 - Central Montane (Figure 36b)

This group includes four taxa not found north of the British Columbia- Yukon
Territory border, or south of northern-most Montana and Washington.

C. n. streckeri B. alberta

E. e. beani B. astarte

TYPE 3 - Disjuncts (Figure 36c)

One taxon found in Alberta represents a disjunction from a northern population.
There do not appear to be any disjunctions from southern populations.

B. i. youngi

TYPE 4 - Endemic forms (Figure 36d)

Included here are two taxa known only from the central Canadian Rocky Mountains.
B. e. nichollae B. n. reiffi

Possibly three other taxa may be placed here. As mentioned earlier, the Alberta population
of Boloria improba may represent an undescribed subspecies. Also, O. m. beani from around
Prospect Mountain shows an ecological specialization which may deserve recognition, and the
one specimen of L. p. arethusa from above treeline at Prospect Mountain is very different
from normal arethusa. This may be an aberration, or it may represent an undescribed taxon.

DISCUSSION

In general, distribution patterns are determined in part by ecological tolerances, or proximal
factors, and in part by past events, or historical factors (Udvardy, 1969; Larsen and Barry,
1974; Love and Love, 1974). I have not attempted to study explicitly by experimental means
those factors involved with ecological tolerance. Rather, I accept that such exist, and assume
that the tundra butterflies of Alberta exist in such areas because the latter are favorable.
Further, I assume that these taxa do not live elsewhere in geographically proximal areas,
because they cannot tolerate other ecological conditions, either biotic or physical. I concentrate
on explaining the historical concomitants of the distribution patterns.

In general, historical explanations depend on a series of hypotheses, because the determining
events were not observed, and thus their existence and interrelations must be inferred from
evidence that is presently available. However, meaningful inferences cannot be generated in
vacuo. Rather, they are based on assumptions that must be regarded, for the sake of a given set
of circumstances, as axiomatic. My assumptions are as follows.

1. Climatic events of the Wisconsin glacial stages influenced the distribution patterns of
extant butterfly taxa of tundra areas of Alberta. There is a vast amount of data which
document the effects of this glaciation on other groups of animals and plants. For the

Tundra butterflies in Alberta

569

present, these effects are assumed for the tundra butterflies as well. Specific indications
derived from distribution patterns shown by tundra butterflies are discussed in the section
on source areas of this fauna.

2. Unglaciated areas of the eastern slopes of the Rocky Mountains were habitable during
glacial times.

This assumption is necessary to explain the presence of disjunct populations of
non-butterfly taxa in the study area, given that these disjunctions are not artifacts and are
interpreted correctly. Geological data (Roed, Mountjoy, Rutter, 1967; Rutter, 1972;
Boydell, 1972; Curry, 1976; Reimchen and Bayrock, 1977; Stalker, 1977; Alley, 1973;
Jackson, 1977; Reeves, 1973) indicate the likelihood that this assumption is valid.

3. Immediate ancestral stocks of all species of butterflies that are included in each
distribution type survived together in the same refugium.

This assumption is required to explain the fact that more than one taxon shows a given
distribution pattern.

4. Dispersal of tundra adapted stocks has been slow and orderly. This has been the result of
the non-random and gradual retreat of Wisconsin ice sheets. Because life spans are short,
and flight capabilities are generally poor* tundra butterflies do not appear to be suited to
dispersal over long distances.

5. Evidence of endemism is evidence of isolation of such stocks from other populations for a
period of time that extends from the present to at least the end of the Sangamon
interglacial stage.

Genetic change usually requires a period of isolation (see Morisset, 1971, and Packer, 1971,
for discussions in the context of endemism and refugia). Endemism is one way that such genetic
change is expressed. The end of the Sangamon interglacial is the last possible time that
endemic populations could have been genetically continuous with ancestral populations of other
forms.

Explanation of the distribution patterns of the tundra butterflies of Alberta requires
postulation of source areas of these populations. There are three potential source areas:
Beringia, Continental North America south of Wisconsin ice, and one or more refugia within
the limits of continental ice along the Rocky Mountains in Alberta and British Columbia. Two
are external to Alberta: Beringia, and Continental North America south of Wisconsin ice. One
includes the eastern slopes of the Rocky Mountains, that is, an internal refugium in the sense
that it was probably surrounded by ice at the height of the Wisconsin glacial stage.

Existence of the external source areas is well established by an abundance of evidence.
Existence of the internal source area is based on less extensive evidence: at least twelve plant
taxa have disjunct populations in the front ranges of the Rocky Mountains (Packer and Vitt,
1974) as do three species of beetles (Belicek, 1976; Ball, pers. comm.), and one crustacean. The
endemic species of crustacean which has been reported (Clifford and Bergstrom, 1976) is of
questionable value in this context.

Extensive areas surrounded by ice were probably available in Alberta during Wisconsin time
for habitation, although much of the unglaciated area was likely bedrock, and probably too
rugged and too high to support tundra vegetation. Today, distribution of disjunct taxa is
concentrated along the front ranges of the Rocky Mountains, and especially in the Mountain
Park area. Endemic taxa are also centered in this area. Possibly the refugium was located in
this area during the Wisconsin stage.

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570

Pike

Figure 37 indicates the approximate limit of Wisconsin ice in the Mountain Park area. A
high ridge on the western side, which now forms the Jasper National Park boundary, would
have prevented ice from entering this area from the west. The northern boundary has been
documented as Cordilleran ice in the Athabasca River Valley which coalesced with laurentide
ice in the vicinity of Hinton (Roed, Mountjoy, and Rutter, 1967) See Figure 5. The eastern
boundary would most likely have been somewhere in the foothills, or the eastern slopes of
Cadomin and Red Cap Mountains. The southern boundary is uncertain, and the refugium may
have extended south to Nordegg, where ice in the Saskatchewan River Valley would have
formed a barrier. The area encompassed is a series of valleys and ridges which run in an
east-west direction. They provide, at present, considerable and varied alpine habitat. All ice
present in the refugium during Wisconsin time would have been thin and of local derivation. It
is probable that small pro-glacial lakes were present during the height of glaciation, being
formed by summer melt waters off the ice and from annual snow fall. Alpine tundra could have
maintained an extent and position similar to that at present.

Of the three possible source areas listed above, I believe that only two contained immediate
ancestors of the extant populations under consideration. My major hypotheses, then, are:

1. The source area for butterflies with distribution types 1 and 2 was an external refugium
south of the ice.

2. The source area for butterflies with distribution types 3 and 4 was an internal, or
Albertan refugium.

Each of these hypotheses is discussed below. Additionally, a series of secondary hypotheses
is presented in conjunction with locating more precisely the source area of the butterflies from
the external refugium south of Wisconsin ice.

The source area of the nine taxa in groups 1 and 2 is placed south of Wisconsin ice for the
following reasons.

Of the nine species involved, five also live in Beringia, and are represented there by
distinctive forms. Alberta material is easily allied with southern forms in all five species. None
of the Beringian forms even approach the Alberta border to the north.

The remaining four species are not in Beringia, and two have clear relationships with
southern taxa. This suggests that they evolved south of the Wisconsin ice sheets.

No tundra butterflies in Beringia have dispersed south into and still survive in Alberta.

In the Trichoptera (Nimmo, 1971) and Coccinellidae (Belicek, 1976) faunas that have been
investigated, only a very small proportion has been derived from Beringia. This includes all
habitat types. Of all Alberta s butterflies, the source area of only one can be identified as
Beringia. This suggests that not only tundra elements, but all elements of the Beringian fauna
could not easily migrate south, including the boreal forest communities.

If these taxa survived Wisconsin glaciations in the Alberta refugium, there are a number of
indications that might be expected.

First, we might expect that some of these taxa would have dispersed north from the
refugium as well as south. There would not be barriers to entry into Alaska for the four species
not present there now. We would alsq expect that some of the distinctly alpine taxa would be
found on arctic tundra in the North West Territories. These possibilities have not been realized.
It is possible that some of these taxa survived in the Alberta refugium, but have not contributed
to colonization of other areas, however, in the absence of endemic tendencies, these cannot be
identified.

Tundra butterflies in Alberta

571

It is also unlikely that taxa surviving in the Alberta refugium could have dispersed as far as
New Mexico in post-glacial times, but not into the coastal ranges of Washington, Oregon, and
California. This would imply long distance dispersal between mountain ranges, and the gaps in
habitat are similar in size on both the eastern and western mountain ranges.

In order to locate the source area of types 1 and 2 more precisely, the following hypotheses
are made.

1. Taxa in types 1 and 2 survived the Wisconsin glaciation in the same refugium.

2. Dispersal south into Wyoming and Colorado from this refugium was blocked by gaps in
habitat.

3. The tundra belt south of the ice sheet was very narrow and broken. This prevented
dispersal east to New England and Quebec.

4. Dispersal west and south along the coastal ranges was blocked by large gaps in habitat in
central Washington.

These hypotheses are discussed below.

1. Taxa in types 1 and 2 survived together.

These taxa have similar boundaries on three sides of their present ranges. This
indicates that they are responding to retreat of Wisconsin ice in a similar manner. If so, it
is reasonable to expect that they would respond to the Wisconsin ice advances in a similar
manner as well, and that as they were displaced south, and northern colonies were
extinguished, the surviving colonies would be found in about the same area.

Type 1 distributions have been identified in plants (Packer and Vitt, 1974),
Trichoptera (Nimmo, 1971), and Coccinellidae (Belicek, 1976). Type 2 distributions have
been identified in Trichoptera (Nimmo, 1971), but not in plants or Coccinellidae. At least
one species of carabid beetle shows this type of distribution: Nebria schwarzi. This
indicates a fairly general phenomenon, and that large elements of the tundra community
were involved. This is to be expected if the hypothesis is correct.

2. Dispersal from this refugium south was blocked by gaps in habitat.

This hypothesis is necessary to explain the fact that type 2 taxa have not dispersed
farther south, where there appears to be ample suitable habitat, and empty niches
available. Because there are no plant taxa which show this type of distribution, these
butterfly taxa are not limited by foodplant distribution. It would seem that they have been
physically blocked from dispersing south. The only reasonable explanation is that tundra
was not very extensive, and that these taxa are not capable of crossing even minor gaps in
habitat. In other words, dispersal can only be accomplished if the habitat is continuous. By
hypothesizing a narrow tundra belt, breaks would occur in the belt in the vicinity of
central Montana, which is where the barrier seems to have been.

Also in support of this hypothesis is the fact that the two endemic taxa in the southern
Rocky Mountains have not been able to disperse north across this barrier.

It would appear that the presence of type 1 taxa in the southern Rocky Mountains
would weaken this argument. However, because two of these taxa are derived from
non-tundra species which evolved below the ice margin, their presence probably dates to
pre-Wisconsin times. Also, because the three species on isolated tundra in New England
and Quebec are also in the Rocky Mountains, they must either be capable of much better
dispersal, or they must have had more time to reach these areas. While they may be more
efficient at dispersing than other tundra butterflies, they have not managed to invade the
arctic islands very successfully, which weakens the suggestion that they extended their

Quaest. Ent., 1980, 16(3,4)

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ranges into the southern Rocky Mountains in post-Wisconsin times.

If they were present in North America during earlier, more extensive glaciations, not
only would the extent of tundra be greater, and therefore the gaps smaller, but they would
have had considerably more time to spread through the southern Rocky Mountains. It is
suggested, therefore, that these taxa represent elements of an older dispersal south,
perhaps during Illinoisan or Nebraskan glaciations. This might also explain the presence
of E. magdalena and E. callias in Colorado and Wyoming.

3. The tundra belt along the southern margin of Wisconsin ice was discontinuous.

Six of the nine species under discussion are not represented in the isolated tundra of
New England and Quebec. The three tundra species there are represented by subspecies
that are more closely related to subspecies in Labrador and the eastern arctic. This
indicates that a major barrier was present. Because the six species that are absent inhabit
a variety of habitats, and two of them inhabit all tundra areas except New England,
Quebec, and the southern Rocky Mountains, it is reasonable to expect that the nature of
this barrier had to be a break in the tundra belt. Otherwise, at least one or two of these
species would be expected on the tundra in New England and Quebec, and the relationship
would be closer between eastern and western populations of the three species found on
both sides of this barrier.

Based on pollen core data, similar conclusions have been reached with respect to the
discontinuous tundra belt (Love, 1959; Ritchie, 1969; Wright, 1970).

4. Dispersal west and south along the coastal ranges was blocked by large gaps in habitat in
central Washington.

Only two of the twelve species in Alberta are also on the coastal ranges, where each is
represented by a different subspecies. Tundras from Oregon south to the Sierra Nevada are the
most depauperate in terms of tundra butterflies, in North America. This indicates a major
barrier. If minor barriers prove to be effective for these butterflies, distances between the
mountain peaks in Oregon and southern Washington would be almost insurmountable. This is
in keeping with the suggestion that the nine taxa in types 1 and 2 are unable to cross
unfavorable habitat, and necessitates only one assumption to explain all boundaries and
barriers encountered in this study.

It appears that tundra plants are also reacting to this barrier. According to Billings (1974),
only 20% of the flora of the tundra of the Sierra Nevada has affinities with northern and arctic
tundra floras. Of all known tundra in North America, this, and that of the Great Basin, are the
most depauperate in arctic-alpine species.

The hypothesis seems to explain all the available data, while being contradicted by none. As
more groups are investigated, particularly Carabidae, and the infraspecific relationships in the
flora between the tundra areas discussed above, further tests of the hypothesis can be made.

The probable extent of the external refugium is indicated in Figure 43.

Before an attempt is made to locate the source area for butterflies with distribution types 3
and 4, it is necessary to discuss the assumptions that the distributions known for these taxa are
accurate.

The only taxon that shows a clear disjunction is B. improba youngi, which is represented in
Alberta by a population disjunct from arctic Canada and Alaska. Collecting in the gap has
been minimal, so there is a possibility that this disjunction is an artifact, in which instance, this
would represent the only dispersal into Alberta from the north in Post-glacial times. Because of
the phenotypical differences between the Prospect Mountain population and the populations in

Tundra butterflies in Alberta

573

the north, and because this species has not been found on the mountains in the vicinity of
Prospect Mountain, I suspect that it probably represents a real disjunction. This would indicate
either long distance dispersal, or survival in the area during the Wisconsin. Because of the
distances involved (over 600 km.) it is unlikely that this represents long range dispersal. Adults
of this species are very weak fliers. The presence of a disjunct population in Colorado supports
the hypothesis that this species has a relict distribution in the Rocky Mountains, and that this
distribution is in part due to Wisconsin events.

Two taxa in type 4 may represent endemic forms. B. e. nichollae is very distinctive. B. n.
reiffi is largely unknown. The type specimen appears to have been lost, and no specimens have
been found that fit the type description. Alberta material has not been studied. A short series
from Pink Mountain, British Columbia has not been examined because of lack of material from
the Yukon Territory and Alaska for comparison. This species must have been present before
the Wisconsin glaciations because there is one disjunct population in Wyoming which
represents a different subspecies.

The only feasible explanation for the presence of types 3 and 4 distributions is that these
taxa survived at least the Classical Wisconsin glaciation in the Alberta Refugium.

Barriers to dispersal appear to be either lack of suitable habitat, or selection against
dispersal during glaciations. This has been suggested for Carabidae (Lindroth, 1949).

Colonization of present day tundra in Alberta

In this section I will discuss the contribution and dispersal routes from each of the two
refugia into Alberta tundra.

Dispersal of taxa which survived Wisconsin glaciations in the Alberta refugium has been
minimal. B. e. nichollae has dispersed west and south to areas within a 40 km. radius of
Prospect Mountain, B. n. reiffi and B. i. youngi are now located to the north of the refugium,
which may indicate Post-glacial dispersal, or possibly that the refugium extended north of the
Athabasca River Valley as a series of broken nunataks. If the ecological form of O. m. beani
found in this area survived in the refugium, it has dispersed about the same amount as B. e.
nichollae. This refugium does not seem to have contributed much to the colonization of Alberta
tundra in Post-glacial times.

With respect to the external refugium, as Wisconsin ice retreated, the tundra south of the
ice is expected to have followed the ice margins north. As the tundra moved northward, the
tundra butterflies would have as well. Boreal forest following behind the tundra would first
invade valleys, gradually isolating pieces of tundra on mountains. With the continued
movements of both communities north, these isolated tundras would slowly move up the
mountains to the summits as conditions for tree growth improved lower down. As ice retreated
still farther, Laurentide ice withdrew to the east across northern Alberta and what is now the
barrenlands of the North West Territories. The tundra belt followed the ice movements and
boreal forest eventually replaced tundra in all the mountain valleys creating a series of isolated
tundra communities on mountain summits. The breakup of continuous tundra in the mountains
effectively halted the dispersal north of tundra butterflies. The migration of the biota in this
refugium is summarized in Figure 38.

Because Cordilleran ice in northern British Columbia and the Yukon Territory did not
break up until well after Laurentide ice had retreated eastward, Beringian flora and fauna were
blocked from dispersing south by the presence of intact tundra and boreal forest communities
derived from south of the ice sheets. In other words, the Beringian communities were blocked

Quaest. Ent., 1980, 16(3,4)

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Pike

first by ice barriers, and later, by inter and intra specific competition.

CONCLUSIONS

Two Wisconsin butterfly refugia can be identified in the Rocky Mountains of Alberta and
adjacent areas. The first, Mountain Park, did not have a significant role in re-colonizing
Alberta after the ice retreated. The second, northern Washington, Idaho, and Montana, was an
important dispersal center for butterflies. Tundra butterflies are the only direct living
indication that the tundra belt south of the ice margin was not continuous.

This suggests that the tundra butterfly fauna has an important potential as an indicator of
refugia, and should be investigated whenever a study on the location of a refugium is
undertaken.

The importance of refugia is twofold. They serve as centers of dispersal, and as centers for
the development of new taxa. This study also suggests that large refugia tend to act as centers
of dispersal, and that small refugia tend to serve as centers for the development of new taxa.

Where areas surrounded by ice have been identified by geologists, evidence which indicates
refugia has usually been found by biologists, but geologists cannot determine the limits of a
given community type within the boundaries of an open, or continental refugium. Only
investigation of the biological components can determine these limits with accuracy.

ACKNOWLEDGEMENTS

I extend my appreciation to my sponsor, Dr. G. E. Ball for arranging financial support from
his National Research Foundation grant A- 1399. I thank J. Shepard and Dr. C. D. Bird for
free access to their collection records, and F. Sperling and T. Thormin for loan of important
reference material.

I gratefully acknowledge Parks Canada for issuing collecting permits in my name for Banff
and Jasper National Parks, Alberta.

Lastly, I thank P. Everson, F. Sperling, and H. Frania for reviewing the manuscript.

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Roed, M.A., Mountjoy, E.W., and Rutter, N.W. 1967. The Athabasca valley erratics train,
Alberta, and Pleistocene ice movements across the continental divide. Canadian
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Rutter, N.W. 1972. Geomorphology and multiple glaciation in the area of Banff, Alberta.

Tundra butterflies in Alberta

579

Geological Survey of Canada Bulletin 206, 54 pages.

Ryan, J.K. 1977. Energy Flow through arctic invertebrates at Truelove lowland, Devon Island,
N.W.T., 75° 40 N 84° 40 W. Ph.D. Thesis. Department of Entomology,
University of Alberta, Edmonton, 239 pages.

Say, T. 1828. American entomology, or descriptions of the insects of North America;

illustrated by coloured figures from original drawings executed from nature, vol. 3.
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Schneider, D.H. 1792. Neustes Magazin fur Liebhaber der Entomology, vol. 2, pages 128-256;
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Skinner, H. 1897. Notes on Rhopalocera, with descriptions of new species and varieties.
Canadian Entomologist 29; 154-156.

Skinner, H., and Mengal, L.W. 1892. Greenland Lepidoptera. Proceedings of the Academy of
Natural Sciences, Philadelphia 1892; 156-159.

Stalker, A. McS. 1977. The probable extent of Classical Wisconsin ice in southern and central
Alberta. Canadian Journal of Earth Science 14; 2614-2619.

Stanford, R.E. 1977. Rocky Mountain butterfly distribution maps. Denver, Colorado. 39
Denver, Colorado. 39 pages.

Strecker, F.H. 1880. Description^ of some new species and varieties of North American
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Udvardy, M.D.F. 1969. Dynamic Zoogeography. Van Nostrand Reinholt Co. New York, xviii
and 445 pages.

Verity, R. 1911. citation not found.

Verity, R. 1932. Notes on the geographical variations and evolution of Boloria pales Schiff.
Iris, Dresden. 46; 101-109.

Warren, B.C.S. 1936. Monograph on the genus Erebia. Adlard and Son, Ltd. London. 407
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Warren, B.C.S. 1944. A review of the classification of the Argynnidi; with a systematic revision
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Watkins, H.T.G. 1928. New satyrid butterflies. Annals and Magazine of Natural History
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Wolley-Dod, F.H. 1907. Notes on Chrysophanus Hypophleas and its allies, with description of
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Wright, H.E. Jr. 1970. Vegetational history of the Great Plains, pages 157-212 in Dort, W. Jr.

and J.K. Jones Jr. (eds.) Pleistocene and Recent environments of the central Great
Plains. Department of Geology, University of Kansas Special Publication 3. 433
pages.

Wright, W.G. 1905. The butterflies of the west coast of the United States; San Francisco.
Entomologists News 16; 336-340.

Wyatt, C.W. 1957. Observations on Boloria distincta (Nymphalidae). Lepidopterists News
11 (4-5): 142-146.

Wyatt, C.W. 1966. Zeitschrift Wien Entomologische Gesellschaft 51; page 93. citation not
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Wynne- Ed wards, V.C. 1937. Isolated arctic and alpine floras on eastern North America: a
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Quaest. Ent., 1980, 16(3,4)

580

Pike

Fig. 1. Important localities mentioned in the text.

A-Prospect Mountain (Mountain Park); B-Shunda Mountain; C-Coliseum Mountain; D-Wilcox Pass; E-Laggan (Lake
Louise); F-Hinton.

Tundra butterflies in Alberta

581

Fig. 2-4. Distribution of butterfly species and subspecies in North America.

Fig. 2. Parnassius eversmanni thor. Fig. 3. @ Colias boothii; ♦C. nastes thula. Fig. 4. ♦ Colias n. nastes; ★ C. n. rossii;
I C- n ■ moina; 0 C. n. streckeri; ▼ C. n. cocandicides; A C. n. aliaska unverified record. See Fig. 3 for range of C. n.
thula.

Quaest. Ent., 1980, 16(3,4)

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Pike

Figs. 5-8. Distribution of butterfly species and subspecies in North America.

Fig. 5 \%Lycaena phlaeas feildeni; A L. p. arethusa; Hi/., p. hypophlaeas. Fig. 6: $ Lycaena s. snowi; © L. s. henryae.
Fig. l.^Euphydryas editha beani; ^ E . e. nubigena; WkE. e. colonia; A E. e. lawrenci. Fig. 8: H Boloria napaea
alaskensis&B. n. nearctica; A B. n. reiffi; ♦ B . n. halli.

Tundra butterflies in Alberta

583

Fig. 9-1 2. Distribution of butterfly species and subspecies in North America.

Fig. 9: A B. i. improba; £ B. i. youngi. Specimens from the locality in Colorado have been described as B. acrocnema
Gall and Sperling, 1980. Fig. 10: Boloria p. polaris; % B. p. groenlandica; A B. p. stellata; identification uncertain.

Fig. 1 1 : Boloria alberta; Fig. 1 2: Boloria astarte.

Quaest. Ent., 1980, 16(3,4)

584

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Fig. 13-15. Distribution of butterfly species and subspecies in North America.

Fig. 13: Boloria distincta. Fig. 14: A Bolaria eunomia nichollae; 0 B. e. ursadentis; % B. e. laddi; ♦#. e. caelestis. Fig.
1 5: ♦ Oeneis bore taygete; ★ O. b. gaspeensis; | O. b. fordid O.b. edwardsi; A O. b. hanburyi; ▼ O. b. mackinleyensis.

Tundra butterflies in Alberta

585

LAMBERT AZIMUTHAL EQUAL- AREA PROJECTION

Figs. 16- 17. Distribution of butterfly species and subspecies in North America.

Fig. 16: | Oeneis m. mellissa; ★D. m. semplei; ♦ O. m. assimillis; WO. m. gibsoni; AD. m. lucilIa.-%0. m. beani; O O.
m. semidea. Fig. 17: ^ O . p. polixenes; WO. p. subhyalina; ^ O . p. katahdin; A O. p. peartiae&O. p. brucei; HD p.
yukonensis.

Quaest. Ent., 1980, 16(3,4)

Figs. 18-23. Distribution of butterfly species and subspecies in North America.

Fig. 18: A.Erebia m. magdalena;%E . m. mackinleyensis. Fig. l9:%Erebia f fasciata; A E. f avinoffi. Fig. 20: A
Erebia y. youngi; $E. y. herscheli;%E. y. rileyi. Fig. 21: Erebia dabanensis. Fig. 22: Erebia callias. Fig. 23: Erebia
inuitica.

Tundra butterflies in Alberta

587

Figs. 24-25. Distribution of butterfly subspecies in Alberta.

A-Banff; S-Jasper. Fig. 24: Colias nastes streckeri. Fig. 25: Lycaena phleas arethusa.

Quaest. Ent., 1980, 16(3,4)

588

Pike

Figs. 26 27: Distribution of butterfly subspecies in Alberta.

A-Banff; S-Jasper. Fig. 26: Lycaena s. snowi. Fig. 27: Euphydryas edit ha beani.

Tundra butterflies in Alberta

589

Glaciers

2000 ft. (610 m.) contours start at
4000 ft. (1220 m.)

Figs. 28-29. Distribution of butterfly subspecies in Alberta.

A-Banff; S-Jasper. Fig. 28: Boloria napaea reiffi. Fig. 29: Boloria improba youngi.

Quaest. Ent., 1980, 16(3,4)

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Pike

Figs. 30-31. Distribution of butterfly species in Alberta.

A-Banff; S-Jasper. Fig. 30: Boloria alberta. Fig. 31: Boloria astarte.

Tundra butterflies in Alberta

591

Figs. 32-33. Distribution of butterfly subspecies in Alberta.

A-Banff; S-Jasper. Fig. 32: Boloria eunomia nichollae.Flg. 33: Oeneis bore edwardsi.

Quaest. Ent., 1980, 16(3,4)

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Pike

Figs. 34-35. Distribution of butterfly subspecies in Alberta.

A-Banff; S-Jasper. Fig. 34: Oeneis melissa beani. Fig. 35: Onenis polixenes brucei.

Tundra butterflies in Alberta

593

36

Fig. 36: Distribution types exhibited by Alberta tundra butterflies.

A-Southern Montane; B-Central Montane; C-Disjunct populations; D-Endemic forms.

Quaest. Ent., 1980, 16(3,4)

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Pike

Mountain Park is indicated by dot “A”.

f

Fig. 38: Retreat of Wisconsinan and recent ice sheets in Western Canada modified after Prest (1969).

A-l 7,000 to 15,000 years before present; B-l 2,000 years before present; C-l 0,000 years before present; D-8,000 years
before present.

Stippled areas correspond to continental ice sheets. Colonization of Alberta by taxa in the refugium south of the ice sheets
is indicated by vertical hatching. In C and D this tundra would be very narrow, perhaps less than 1 kilometer. In D, line ‘a’
indicates limit of northern dispersal.

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MATING AND NESTING BEHAVIOR OF EURYSTERNUS (COLEOPTERA:

SCARABAEINAE

Gotizalo Halffter
Violet a Halffter
Carmen Huerta
Instituto de Ecologta
Apart ado Postal 18-845

Mexico 18, D. F.

Quaestiones Entomologicae
16:599-620 1980

ABSTRACT

Mating and nesting behavior of Eurysternus caribaeus, magnus and balachowskyi show
features which distinguish them from other scarabaeines and which collectively define a
distinct group of nesting behavior designated Pattern VI by Halffter (1977). These
distinguishing features are: a) the “nuptial feast”, a massive formation of dung balls by the
female initiating nesting ; b) partial consumption and abandonment of these balls by the
parent (s); c) lack of ball-rolling; d) multiple nests, comprising several brood balls; e) nest care
by the female; f) in some species, formation of a pair bond while nesting is in progress; g)
destruction of some or all brood balls after a period of nest care (such nests are termed
experimental nests); h) repetition of experimental nesting with intermittent periods of feeding
until a final, or definitive nest is constructed and cared for until the emergence of progeny.
Balls are made only by the female and only during nesting behavior; they are not made for
feeding, although some may be consumed.

Histological study of the ovary ofE. caribaeus suggests that attack and abandonment of an
experimental nest is linked to continuation of oocyte development during the period of nest
care. Disparity between ovarial function and nest care (which represents a fault in the normal
K-strategy of scarabaeines) is evidently what provokes the attack and abandonment of a nest
after several days of intensive care.

Nesting behavior of E. foedus and an unidentified Mexican species are not like that of the
species studied. Rather, their behavior is like that of certain Onitini, and is assignable to
Group I behavior fsensu Halffter and Matthews, 1966).

RESUMEN

En este trabajo se presenta el comportamiento en la reproduction y la nidificacion de tres especies de Eurysternus: E.
caribaeus, E. magnus y E. balachowskyi discutiendose las caracteristicas comunes a estas tres especies y a E. mexicanus,
asi como sus diferencias.

598

Halffter, Halffter and Huerta

El comportamiento reproductor de las cuatro expecies antes mencionadas tiene rasgos muy particulars que lo
separan claramente de las pautas seguidas por los dem'as Scarabaeinae, lo que llevo a Halffter 1977 a const ituir el
llamado grupo VI dentro patrones de nidificacion de la subfamilia. Estas caracteristicas peculiares ban quedado
confirmadas y ampliadas por este trabajo. Las mas importantes son:

1. Una secuencia en la nidification que se inicia con la formacion masiva de bolas por la hembra (festin nupcial),
durante la cual o inmediatamente despues ocurre la copula; el festin nupcial es seguido por la preparacion de un
nido multiple (con varias bolas-nido) en forma de crater que - en la mayor parte de las especies- despues de un
periodo de cuidados es atacado por la propia madre y abandonado ( nidificacion experimental ) o cuidado hasta la
emergencia (nidificacion definitiva). Cuando se presenta nidificacion experimental, al primer nido abandonado
puede suceder el nido definitivo o bien varios nidos experimentales hasta llegar al definitivo, que en E.
balachowskyi es de construccion distinta al experimental. Los nidos definitivos son cuidados hasta la emergencia
de la progenie.

2. Solo la hembra hace bolas y unicamente en relacion con el proceso reproductor. No hay rodaje de las bolas.

3. Asociamos el ataque y abandono de las bolas (basandonos en el estudio histologico del ovario de E. caribaeus, a
una continuacion del desarrollo y maduracion de oocitos durante el periodo de cuidados del o los nidos
experimentales, fenomeno que no se presenta en los otros Scarabaeinae estudiados, cuyo comportamiento incluye
cuidados prolongados al nido y cese de la oviposicion. Este desajuste entre el funcionamiento del ovario y los
cuidados al nido (ecologicamente una falla en la estrategia K tipica de los Scarabaeinae) es el que consideramos
que provoca, despues de varios dias de cuidados intensivos, que las bolas-nido vayan siendo atacadas, hasta ser el
nido experimental abandonado.

Ademas de un estudio detallado de los cuidados y construccion de los nidos en las tres especies, el trabajo incluye
una descripcion preliminar del funcionamiento del ovario en E. caribaeus y su relacion con el comportamiento; la
description de la formacion de la pareja bisexual y del papel del macho en la nidificacion; la descripcion del
mecanismo de copula, incluyendo el papel de un curioso peine de sedas del apice de las tibias anteriores del macho.
Tambien es estudiado el espermatoforo, comparandolo con los otros conocidos de Scarabaeinae, y otros aspectos del
comportamiento: la oviposicion, asi como despliegues de agresion y limpieza, y varias pautas interesantes directamente
relacionadas con la peculiar disposicion de las patas medias y de las partes laterales del pronoto, que permiten un
particular desplazamiento del animal boca arriba, asi como el retoque y cuidado de las bolas, haciendolas girar el
animal boca arriba entre las patas anteriores y posteriores.

TABLE OF CONTENTS

Introduction 598

Eurysternus Behavior 600

E. caribaeus (Herbst) 600

E. magnus Laporte 610

E. balachowskyi Halffter and Halffter 613

Discussion 616

Acknowledgements 618

References 618

INTRODUCTION

Mating and nesting bevavior of adult Eurysternus , of the monobasic tribe Eurysternini, is
unique in that it does not conform to described patterns for other Scarabaeinae (Halffter,
1977). Reproductive behavior of these adults does not conform well to either of the two main
lines of feeding and nesting behavior, the latter being interpreted as derivations of feeding

Mating and nesting behavior of Eurysternus

599

behavior. These lines are the burrowing scarabaeines (tribes Onthophagini, Oniticellini, Onitini
and Coprini) and the ball-rolling scarabaeines (tribe Scarabaeini). The behavioral uniqueness
of Eurysternus adults was pointed out by Halffter and Matthews (1966). They were unable to
relate the pattern to other groups because of inadequate knowledge. Halffter (1977) created a
special group, Group VI, based on his studies of E. magnus Laporte, E. balachowskyi Halffter
and Halffter and E. mexicanus Harold, to accomodate Eurysternus in the evolutionary
sequence proposed by Halffter and Matthews (1966). Group VI is characterized as follows: a)
initiation of nesting process by elaboration of numerous balls by the female; b) partial
consumption and abandonment of these balls; c) lack of ball-rolling; d) multiple nests (nests
comprising several brood balls) of one or two types in the same species; e) nest care by the
female alone; f) in some species, formation of pair bond while nesting is in progress; g)
destruction of some or all brood balls after a period of care; h) repetition of ball construction
with intermediate periods of feeding directly from an excrement mass without ball
construction.

Certain morphological features of Eurysternus are directly related to reproductive behavior
(Halffter and Halffter 1977). Both morphologically and behaviorally, Eurysternus is a group
isolated from the two main evolutionary lines of Scarabaeinae, the burying scarabaeines and
the ball-rolling scarabaeines. It originated in South America, from which it expanded into
Central America and Mexico (Typical Neotropical Dispersal, sensu Halffter, 1964, 1976).

This paper describes in detail nidification and certain other behavior aspects of E.
caribaeus , E. magnus and E. balachowskyi. Nesting behavior of these three species collectively
shows a trend from more generalized to one progressively more complex. General aspects of
Eurysternus behavior are covered in the description of E. caribaeus; only distinguishing
features of the behavior of E. magnus and E. balachowskyi are considered.

Descriptions are based upon laboratory observations. We did not observe a Eurysternus nest
in the field (most Eurysternus inhabit tropical forests). Halffter and Matthews’ account (1966)
of a nest of E. magnus observed in the field by H. F. Howden agrees with our laboratory
findings; moreover, A. Martinez (in litt.) reports observing the nest of a South American
species in the field which resembles those described here.

In all other known scarabaeines the nesting process is derived from feeding behavior. In
Eurysternus , however, this relationship is not clear. Nidification behavior of adults of this
genus is not related to their feeding behavior; moreover, it is not directly derivable from that of
either the Scarabaeini or burying groups.

In all observed species (the 3 studied here plus 4 others) ball making has not been observed
outside the nesting process; that is, balls are fashioned only in a reproductive context.
Moreover, even though Eurysternus adults are capable of making balls, they cannot roll them
with the legs in the scarabaeine manner; if moved at all, they are butted along with the head.
The facts that balls are fashioned only for reproductive purposes, that they are produced in
large number (during the “nuptial feast” and that they are not rolled by their makers clearly
distinguish the behavior of Eurysternus adults from those of groups IV and V (Scarabaeini).
Some, principally Australian Canthonines cannot fashion brood balls (Matthews, 1974); but all
of them can roll pieces of excrement which are small enough and whose shape allows it. This
observation would support the hypothesis that rolling was an evolutionary antecedent to ball
making (Halffter and Matthews, 1966; Matthews, 1974); but it could also be considered an
adaptation to special characteristics of the predominant type of dung in Australia, namely
pellets of marsupials. In Eurysternus , however, the situation is diametrically opposed; rolling

Quaest. Ent., 1980, 16 (3,4)

600

Halffter, Halffter and Huerta

capability of adults is lacking while ability to make balls is highly developed.

For all species of Eurysternus known to us, adults can feed directly from a source of
excrement for as long as 200 days without fashioning balls, which are made only by the female.
Their production signals onset of reproductive activity. As Halffter (1977) points out, the
nidification process in Eurysternus comprises 3 stages: 1) nuptial feast; 2) experimental
nesting; 3) definitive nesting. In all three species studied, the female can repeat the process
three or four times under conditions which presumably preclude ecological restrictions. These
species have exceptionally long adult lifespans for Scarabaeinae, which may exceed two years.

Eurysternus Behavior

E. caribaeus (Herbst)

All material upon which the following observations are based were field-collected in two
neighboring localities in the Lacandon rain forest, Chiapas, Mexico: Chansayab-Lacanja and
Bonampak. E. caribaeus occurs from Formosa, Argentina northward to Honduras (Halffter
and Halffter, 1977). All material studied came from more northern populations which could
represent a distinct species or subspecies neither of which was formally decided by Halffter and
Halffter, (1977) because of a lack of sufficient data on the intraspecific variation of the South
American E. caribaeus. Distinctive features of populations from which study specimens came
are the almost uniformly dark dorsal and ventral surfaces (some specimens show the spotted
appearance of typical E. caribaeus) and somewhat shorter average length.

Elaboration of balls, the nuptial feast. - The nuptial feast begins suddenly with rapid
construction of a large number of balls by a female. We suppose that its initiation is linked to
developmental state of the ovary. E. caribaeus females construct two to four balls within three
or four days after emergence when oocytes have barely begun to develop. Nevertheless,
construction stops very quickly.

Once the nuptial feast has begun, the female is soon joined by a male. If a male does not
arrive, the process is interrupted; we did not observe a nuptial feast completed by females
isolated from males. Moreover, except for premature initiation of nidification (as mentioned
above) females do not make balls if they are maintained in the absence of male contact.

Balls are made rapidly during the nuptial feast in the following fashion by E. caribaeus
females; work begins in the lower part of the dung mass using the head and front tibiae while
the middle tibiae are extended upward or rested on the dung and the posterior tibiae are rested
on the ground or dung. A female enters a dung mass and separates a dung ball (Fig. 1) using
the middle legs like oars to move herself in a manner unique to Eurysternus. From an
upside-down position the middle legs are moved anteriorly beneath the dorsal surface while the
tips of the tibiae are planted. Thus, the tips serve as support points for forward movement of the
entire body. Such movement of the tibiae is permitted by the rounded shape of the pronotum
(Halffter and Halffter, 1977). This “rowing” movement has also been observed in females of E.
magnus and E. balachowskyi.

Once the ball is separated, the female begins another from within the cavity resulting from
construction of the first, or to one side of it. Formation of each ball takes about 50 minutes;
females of all three species, make balls continuously. Nevertheless, interruptions of up to
several days can occur, after which a female resumes ball fabrication. Such interruptions cause
marked variation in number of balls produced and duration of ball making (see Table 1).

Mating and nesting behavior of Eurysternus

601

Fig. 1. Eurysternus caribaeus Hbst.. a-g: successive stages in the elaboration of a ball during nuptial feast

Balls produced during the nuptial feast are not exactly spherical nor uniform in size.
Although eggs may be laid in from two to five of them by females of E. caribaeus , most balls
are without eggs.

When a female has been deprived of male contact, she may begin ball making but the
number does not exceed four. Production of many balls requires presence of a male, as does
completion of the nidification process.

During the nuptial feast, both sexes of all three species eat directly from the dung source or
from balls fashioned by the female, most of which are partially consumed and later abandoned.

Quaest. Ent., 1980, 16 (3,4)

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Halffter, Halffter and Huerta

TABLE I

COMPARISON OF ASPECTS OF NESTING BEHAVIOR OF THREE

SPECIES OF

Eurysternus

ASPECT

SPECIES OF Eurysternus

E. caribaeus

E. magnus

E.

balachowskyi

A1

16- 94, x =

9-11, max.=

max.= 55 +

34.5

17

31-50, during
expt. nesting.

B2

7- 69, x =
29.8

12- 28

60- 90

C3 4

65- 80

not observed

not observed

D4

13-82

1

continuous

E5 6

2- 6, x = 4.2

3

F6

38-53

25- 26

40

1 Number of balls made during the nuptial feast.

2 Duration of the nuptial feast (in days) from the making of the first nesting sequence,
during which ball-making may continue interrupted or not.

3 Duration of copulation, in minutes.

4 Period (in days) between the end of the nuptial feast and beginning of next nest.

5 Final number of balls in the definitive nest.

6 Duration (in days) of the definitive nest.

Mating and nesting behavior of Eurysternus

603

Ovary development and behavior. - As is true for females of all Scarabaeinae (Halffter and
Lopez, 1977), the ovary of a Eurysternus female consists of a single ovariole (on the left side).
The ovaries of E. caribaeus females possess two characters which are unusual to scarabaeines,
particularly to those with advanced nidification: 1) the adult emerges with a completely
developed germarium and 2) oocyte maturation begins very soon and is rapid. It appears
contradictory that even when a female is provided necessary male company (in a terrarium),
the nuptial feast does not begin for at least 20, and as many as 50 days thereafter. Moreover, an
additional delay results from the nuptial feast itself and periods during which it may be
interrupted. Why there is such a long delay in egg production in spite of the ovarial condition of
a newly emerged female may be explained by a prolonged period of vitellogenesis, which is
much longer and morphologically more elaborate than in any of the few other scarabaeines
females studied (Fig. 2).

The fecundity of Eurysternus females more nearly approaches that of a scarabaeines with
primitive nidification, such as Onthophagus , than that of one with more advanced nidification.
This high fecundity may explain destruction and abandonment of experimental nests to begin a
new nest ( E . caribaeus, E. balachowskyi and E. mexicanus). High fecundity is perhaps also the
explanation of frantic formation of balls during the nuptial feast, most of which are not used. In
addition, the following ecological fact may obtain: the high number of balls may serve to
compensate for losses through robbery by ball-rolling scarabaeines, losses which should be
important during fierce competition for excrement within tropical forest.

Upon emerging, the germarium of E. caribaeus is completely developed (Fig. 2-a) but does
not contain developing oocytes. Three days after emergence, two developing oocytes and two
nascent ones are at the base of the germarium (Fig. 2-b). Such a rapid development of oocytes
is completely out of the ordinary for scarabaeines. Nineteen days after emergence, still before
beginning the nuptial feast, the ovariole bears 6 oocytes (Fig. 2-c), within the most mature of
which are lipid globules while at the same time the germarium is reduced.

The nuptial feast begins a few days later when the ovariole contains a series of oocytes of
which the first ones are mature. During the feast (the function of which appears to be
attraction of a male) copulation can occur at any time. Figure 2-d illustrates an ovary of a
female during the nuptial feast immediately after copulation: four oocytes contain large
quantities of granules; the fifth and sixth are forming. During this stage as many as eight
oocytes in various stages of development are distinguished.

If a male is present, the nuptial feast develops; if copulation occurs, some days later
(depending upon the state of maturation of the ovary) nidification continues.

We suppose that destruction and abandonment of brood balls in experimental nests are due
to continuation of oocyte formation. Whatever the mechanism is in other scarabaeines
(Halffter and Lopez, 1977) which, in concert with ovarial development, determines female
behavior and which, in turn (according to the phase of reproductive behavior) inhibits the
ovary, it does not function in Eurysternus. Unlike other groups with complex nidification
(Groups II, III and V, Halffter, 1977), the ovary of a Eurysternus female continues oocyte
production, she continues ovipositing in new brood balls and simultaneously attacks or
abandons those which were being cared for.

We suppose that these continuous processes end with completion of the first series of
oocytes, at which time the female ceases destruction and initiates care of what will be the
definitive nest.

Quaest. Ent., 1980, 16 (3,4)

604

Halffter, Halffter and Huerta

Fig. 2. Development of ovary in Eurysternus caribaeus Hbst.a: One day after emergence, there is no differentiation in
germarium formed by cells with very pigmented nucleus (trophocytes) and cells with nucleus less pigmented (oocytes) -
see detail; other details indicating the tunica propia and the inner and outer layers, as well as the mass of prefolicular
cells; b : three days after emergence - two oocytes in vitellogenesis, several in initial process of development in the base

During care of the definitive nest (Table 1), a new series of oocytes matures in females of E.
caribaeus. Toward the end of care, the ovary resembles that observed in the midst of the nuptial
feast. Copulation may occur at this time and a second nidification process begins immediately
after termination of the first (even before emergence of offspring) without an intermediate
feeding period.

Variability of duration of the nuptial feast as well as timing of copulation explains why eggs
are in some (but few relative to the total) balls of the nuptial feast of E. caribaeus. This
indicates that the first oocytes can mature before the end of the feast, at least under laboratory
conditions. We do not know if in the field, under conditions of intense competition, prolonged
nuptial feasts are possible without balls being robbed.

Formation of the bisexual pair. - In all three species studied, a male joins a female during
the nuptial feast in the midst of ball formation. As in Phanaeus, (Coprini; Halffter, Halffter,

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605

of germarium; c : 30 days after (before the beginning of nuptial feast - development of the vitellarium, in the
germarium, trophocytes tend to concentrate in the apical extreme; d: vitellarium 45 days after emergence, in the middle
of the nuptial feast, immediately after copulation - the more mature oocytes are close to oviposition.

and Lopez, 1974) but unlike Scarabaeini, a female’s activity attracts a male. In Eurysternus ,
formation of brood balls acts as an attractant for a male.

In E. caribaeus , the pair remains intact only during the nuptial feast. In E. magnus and E.
balachowskyi, pairing is maintained through experimental nidification. Most females of all
three species are alone during preparation and care of the definitive nest. Nevertheless, in E.
caribaeus we have seen copulation in a definitive nest during the period of care. This copulation
is part of the second nidification process to follow and likely owes its occurrence to conditions
within the terrarium, which prevent the male from leavingy and favor encounter with the
female during maturation of the new series of oocytes. In the field a female may encounter
another male upon beginning a new nuptial feast after emergence and dispersal of her offspring
and an intermediate feeding period.

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Copulation. - Normally in each reproductive cycle a single copulation occurs during the
nuptial feast (among the balls or at the side of the dung mass, Fig. 3). It may also occur a
second time during care of the definitive nest or during the last phase of care of the definitive
nest in E. caribaeus, but when it does it results in abandonment of the nest and initiation of a
new nidification process. In E. caribaeus , the male approaches the female from behind and
mounts her while tapping her elytra with the front legs while supporting himself on the ground
with the hind legs. The middle legs are held extended dorsolaterally. Meanwhile, the female
remains quiet and continues feeding. In a few minutes, the male has situated himself
horizontally over the female (Fig. 3) while grasping her abdomen with his back legs, the tibiae
of which are curved to facilitate hanging on. (To different degrees, this curvature of the hind
tibiae is a secondary sexual feature of all male Eurysternus studied). Meanwhile the middle
legs remain extended while the anterior legs softly caress the pronotum. At this moment, the
aedeagus is extended but not yet engaged in the female genital opening. The female, which up
to now had remained quiet, begins a series of movements which result in the pair being upside
down or lying on one side. The male remains strongly attached while continuing to caress the
female. When the female ceases movement, the male introduces the aedeagus and inserts the
internal sac.

The female remains quiet 30 to 45 minutes before resuming her movements. The male
remains astride her but disengages the internal sac and withdraws the aedeagus. The female
finally succeeds in separating herself from the male using strong movements. Observed
copulations have lasted 65 to 80 minutes.

Fig. 3. Eurysternus caribaeus Hbst. Copulation during nuptial feast.

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Fig. 4. Eurysternus caribaeus Hbst. Spermatophore immediately after its deposit in vagina.

Halffter and Halffter (1977) describe a curious lobe bearing a comb of setae on the apex of
the male tibia. They believed the structure to somehow be related to the fact that a male
sometimes cares for brood balls; that is, that the combed lobes were used to clear or otherwise
retouch the brood balls. Such now appears not to be so. The structures appear to be important
to stimulation of a female during copulation. This is the first structure of scarabaeines directly
and clearly related to sexual stimulation. Although similar stimulation appears characteristic of
scarabaeines in general, Eurysternus is the only group with a special morphological
modification which complements it, although males of several Onthophagus have a tuft of setae
at the apex of the anterior tibia.

In E. caribaeus the spermatophore is a very long, translucent tube containing spermatozoans
(Fig. 4). The ovoid shape of the compacted tube suggests a circular movement during
ejaculation with a gradual retraction of the free tip of the internal sac. This movement occurs in
spite of the spines of the internal sac which contact the sclerites of the wall of the vagina. The
few spermatophores known for other species have different forms indicating a different
movement during deposition (Heymons, 1930; Huerta, 1977; Halffter and Lopez, 1977).

The spermatophore occupies more than half the vagina. Form of the spermatheca,
spermathecal muscle and spermatozoans suggest that insemination follows a process like or
very similar to that observed in Phanaeus (Halffter and Lopez, 1977).

When copulation is complete, the crater-like nest is not immediately begun. Since
copulation can occur at any time during the nuptial feast, the time between copulation and

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crater construction varies. Moreover, some balls made during the nuptial feast are provided
with eggs. Thus, relatively rarely, copulation and complete maturation of some oocytes begins
so early that some balls receive eggs during the nuptial feast. The chances that these eggs later
develop are remote since most are destroyed by the parents or left uncared for.

Nidification. - The nuptial feast is followed by experimental nesting which is not as distinct
an event in E. caribaeus as in E. balachowskyi.

Fig. 5. Eurysternus caribaeus Hbst. Female caring for definitive nest.

In E. caribaeus , experimental nesting is represented by those beginnings of craters and
brood balls which are abandoned by the female. Experimental nests occur in 65% of observed
cases; 35% of observed nidification by caribaeus included no experimental phase.

Definitive nesting.. - Preparation of a definitive nest is strictly linked to state of the ovary;
its timing corresponds with maturation of the last oocytes of a single series. (Recall that the life
of a female may, however, include several series). We believe that nest destruction is inhibited
by and continuous care maintained by, an interruption in maturation of oocytes. Conversely,
nest care behavior acts as a temporary inhibitor of oocyte maturation. Evidently female
behavior changes during definitive nesting such that ball destruction and abandonment are not
manifested.

In E. caribaeus , nidification (definitive or experimental) begins 13 to 82 days after the end
of the nuptial feast. This variation is due to differences in the timing of copulation and
maturation of oocytes.

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609

The definitive nest of E. caribaeus is a crater dug by the female, beneath several previously
fashioned balls; several other balls may be pushed into the crater. Initially, the crater contains
seven to 12 (average 8.7) balls, of which two to six (average 4.2) remain in the completed nest.
The latter are provided eggs and an external layer of soil.

To prepare the definitive nest a female uses the last balls made during the nuptial feast.
They receive final modelling, which results in their being larger than balls constructed
previously (seen also in E. magnus ). The balls are slightly increased in diameter as the nest
develops. The average diameter of balls containing eggs is 23.9 mm; that of balls containing
larvae, 24.7. This increase is produced by the larva by its continual repair to the internal
surface using its excrement without breaking the wall and the action of the mother on the
outside surface.

In the definitive nest, brood balls are carefully modelled and covered with a layer of soil, which
often binds two to four balls into a single, compound structure (Fig. 6).

Fig. 6. Eurysternus caribaeus Hbst. Types of definitive nest. Observe the union of brood-balls with soil.

Nest abortion, or cessation of care and abandonment or attack of balls occurs before the soil
layer is added. Protection of the soil layer is ended when the larvae reach the third instar.

Nest formation is not rapid since it includes much modelling and remodelling and spaced
oviposition. Thus, a single nest may include balls with eggs and other with larvae in all stages of
development. Toward the end, development stages among progeny tend to become equalized.

As a nest develops, a female may depart for several hours to feed, but she returns. She cares
for brood balls in the definitive nest until emergence of new adults. A male does not participate
in nest care; normally he is not present. The nest crater can be to the side of the dung mass
from which the brood balls were extracted or beneath it. If beneath, the nest crater is
hemispherical. Definitive nesting lasts 38-53 days, during which a female maintains constant
care. If copulation occurs during the care period, within a few days after emergence of progeny
the female begins a new nesting cycle by initiating a new nesting process.

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Lapse of time between two nests depends upon whether or not copulation occurs during care
of the definitive nest. One female, which had copulated 20 days previously, began a new
nidification beneath the nest she was caring for. At the time the nest balls contained pupae,
whose care she abondoned (Fig. 7). The new nest was not finished.

Eurysternus magnus Laporte

Material upon which the following observations are based was collected at Lagunas de
Montebello, Chiapas, an area of pine - Liquidambar forests at 1400 m near the Guatemalan
border.

Cleaning. - The system of self-cleaning by E. magnus adults is probably used by those of the
other two species studied. Dorsal surfaces of the elytra are cleaned with the middle tibiae and
tarsi; apices, with the hind tarsi. All Eurysternus adults bear numerous ocellate punctures, each
with a central seta, particularly on the pronotum. These punctures easily collect dry excrement
and dirt, which normally cover part of the entire dorsum. “Dirty” appearance coupled with
normally obscure brown or black coloration results in a rather striking cryptic coloration.
Adaptiveness of the cryptic appearance is enhanced behaviorally by the habit of remaining
motionless (thanatosis) such that Eurysternus adults are exceedingly difficult to see in their

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611

natural surroundings. Presumably this cryptic coloration offsets increased vulnerability of these
beetles resulting from the fact that they do not burrow like almost all other scarabaeines.

Ball construction, nuptial feast. - We have observed E. magnus adults feeding directly from
dung for as many as 190 days. Some enter the dung mass superficially to eat. The nuptial feast
begins suddenly as in E. caribaeus. Number of balls prepared varies from nine to 1 1; Maximum
observed was 17. These balls are eaten, changed in position, destroyed and remodelled and only
a small portion is used for nesting.

Balls are separated from the margin of the dung mass in contact with the ground. The
female may separate the ball in an upside-down position using the front legs (cf. E. caribaeus ).
The margin of the dung mass presents concavities in places where balls have been separated.
Balls are constructed rapidly but with little care until the dung mass is exhausted. Rhythm of
construction is not uniform but is continuous. Fresh balls are only roughly spherical, not
smoothed over and with an approximate diameter of 15 mm. During intensive ball-making,
some are moved randomly on occasion (up to 9 cm) by pushing with the head and forebody
while planting the front and hind legs. Pushing is not continuous, but rather is achieved by a
series of butting motions.

Nesting. - Definitive nesting occurs from 12 to 28 days after beginning the nuptial feast.
Females of E. magnus do not construct experimental nests. The nuptial feast is followed by the
excavation of the nest crater, which is not destroyed, as are 65% of the nests of E. caribaeus
and all nests of E. balachowskyi.

A nest is begun with balls from the nuptial feast, which are remodeled superficially by
adding excrement. The crater is dug beneath three of these balls; excavation requires a day.
The finished crater is shallow, circular and about 5 cm in diameter (diameter of the rim is
somewhat less than that of the floor). The day after finishing the crater, about three more balls
are pushed into it. Thus, at first the nest contains more balls than will be converted into brood
balls, generally three (Fig. 9). The extra balls are used for food, to finish the brood balls or
simply taken apart.

A few hours after finishing the crater, a female models or retouches the balls and begins
oviposition even though all balls will not receive eggs. Two days after nesting is begun, a female
begins adding soil cover to the balls; this activity lasts as long as seven days. After oviposition
and covering are completed, brood balls are cared for continuously throughout development of
offspring.

As the brood balls are cared for, their positions are changed continously by pushing or, in an
upside-down position, by making them turn using the front and hind legs from beneath or from
the side (Fig. 8). The front tibiae are used to retouch and smooth their surfaces. Balls are cared
for alternatively and continuously and are not joined with soil as in brood balls of E. caribaeus
(Fig. 9). Although a ball may be attacked, the nest is not destroyed.

Once we have seen a male caring for brood balls, changing their position frequently while
the female continued to fashion balls from the nearby dung mass until it was exhausted. Some
of these balls were eaten, others simply abandoned. A male of E. magnus remains with a female
during nest formation and during part of the period of care. Rarely a female and much more
frequently a male may, for a short time, move to feed from a nearby dung mass before
returning to the nest.

As in E. caribaeus , brood balls are increased in size during development. Balls constructed
for the nuptial feast have an average diameter of 15 mm when formed from the dung source.

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Fig. 8. Eurysternus magnus Laporte. Female turning nest ball in interior of crater.

After being remodelled (using fragments from other balls or from the dung source itself) the
diameter exceeds 18 mm. The brood balls have an average diameter of 21 mm.

Subsequent nests of E. magnus are not constructed as rapidly as are nests of and E.
caribaeus. About 170 days elapse between emergence of adult progeny and initiation of a new
nuptial feast.

Oviposition. - We have observed oviposition in detail only by females of E. magnus but
believe it must be similar in E. caribaeus and E. balachowskyi. Using her front legs, a female
forms a hole in a prepared ball into which she enters almost completely and remains about five
minutes. Afterwards, she withdraws, turns, and introduces her abdomen. For another five
minutes, the hind legs are moved up and down while the middle legs rub the sides of the body.
Oviposition is in the bottom of the cavity. The female then collects dung from the same ball to
close the egg cavity using the front legs to work it into the opening as she turns around it.
Oviposition lasts 25 minutes, after which the egg remains in a small central cavity.

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613

Fig. 9. Eurysternus magnus Laporte. Definitive nest. Observe balls are not united by soil.

Eurysternus balachowskyi Halffter and Halffter

Observations are based on material from French Guiana (see Halffter and Halffter, 1977).

Ball-making, nuptial feast. - The nuptial feast of adults of this species is the largest (to 55
balls) and longest (to two or three months) of those species studied. Many of the balls are
abandoned or partially consumed. No eggs have been found in nuptial feast balls. Although ball
making is not suspended for more than a few days its rhythm is not uniform. Thus, for some
days a female makes no balls, but on others she may make several.

Balls can be separated from the upper part of a dung mass and from there rolled to the
ground. A female may work right side up or upside down, but either way she separates
excrement in small bits which are molded into a ball. The front legs are used to incorporate and
press the dung while the back legs, by making the mass turn between them, give the ball its
spherical shape. The middle legs remain free to either support the body or to move it with
oar-like movements as described for E. caribaeus.

Ball-making by E. balachowskyi females differs from that of E. caribaeus in that, rather
than separating an entire ball from a dung mass in a single operation, it is gradually built up by
fragments added to the growing ball by the front legs. Completed balls either accumulate to
one side of the dung mass or they are pushed short distanaces. They are not exactly spherical;
the lesser diameter varies between 15 and 18 mm while the greater varies between 15 and 20.

Some of the balls are retouched at one side of, or some distance from the dung mass. As
balls are moved, they are grouped; some of each group are retouched. Some smaller balls are
combined with larger ones, upon which the beetle perches as it pulls and incorporates the
smaller with the front legs. Debris produced by retouching include small pieces of dung, small
balls, including some already worked. The front legs press and smooth the surface of the ball;

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later a thin layer of soil is added. Retouching includes spinning the ball with the front and back
legs while the female is upside down.

At the end of the nuptial feast, some retouched balls receive eggs. The first oviposition
begins the experimental nesting phase; during the nuptial feast (in the strict sense) no balls
receive eggs.

Oviposition is followed by formation of a nest crater. In the other two species, crater
excavation precedes or coincides with oviposition.

Experimental nesting. - For approximately 60 days after the nuptial feast, a female
oviposits in a number of balls and constructs about three successive craters where the balls are
placed and cared for a few days before they are attacked, partially consumed and abandoned.

In contrast to the other two species, the female continues ball-making during experimental
nesting (31 to 50 additional balls ) if excrement is nearby. Undoubtedly, this prolonged process
of ball-making is related to destruction and abandonment of experimental nest craters. The
nuptial feast, with its characteristic elaboration of balls, overlaps with experimental nesting,
with its oviposition and formation of nest craters. This overlap we attribute to a continuously
active ovary, which by not ceasing activity, fails to produce the metabolic signal that the nest
should be cared for and ball-making ended.

Balls made during experimental nesting and at the end of the nuptial feast have two possible
fates: some are abandoned, whether or not they contain eggs; others are taken apart and
partially eaten, whether or not they contain eggs. Some eggs in balls removed from terraria
develop; others do not.

Preparation of the nest crater is very similar to that of E. magnus and E. caribaeus females.
Some balls are provided with a thin soil covering. As for E. magnus , the male of E.
balachowskyi often remains with the female and can participate in care of the brood balls.
Remodelling of the balls in the nest crater and their care is exactly as described for E. magnus.
Within a few days, four or five well worked balls are in the nest crater; of these, three large
ones finally remain and (rarely two) are completely finished and with eggs and a thin layer of
soil. They are cared for by the female. About two days later, one of the balls is eaten by one of
the parents, but the female continues caring for the others for approximately six days. During
this time the female does not leave them but attacks and partially consumes some of them.
Eight days after the first attack, most balls have been damaged by the parents and the nest
crater is abandoned.

During the period a male or female may eat from a nearby dung mass (the attack is not
occasioned by hunger) and, moreover, the female may make other balls which are pushed into
the crater and ultimately destroyed. Some balls may by chance survive the attacks and the egg
continues its development.

After a period of direct feeding, experimental nesting is repeated, generally three times,
with the consequent abandonment of the nests.

Oviposition is similar to that by E. magnus females. Each egg is in a chamber near the
upper pole of the brood ball closed by a plug of loosely compacted grass fibers. Oviposition can
occur either on the surface, after massive ball-making, or in the nest-crater.

Definitive nesting. - The definitive nest of E. balachowskyi adults is different from
experimental nests in both how it is made and in its final structure. Of the last balls made, two
are separated for definitive nesting. This separation begins definitive nesting and occurs about
five months after beginning of the nuptial feast and about two months after the first oviposition
and experimental nest. The two balls selected have diameters exceeding 27 mm; they are placed

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615

Fig. 10. Eurysternus balachowskyi Halffter and Halffter.a-d\ stages in formation of definitive nest in dorsal view.- two
brood balls united with soil and peripheral groove deepens; e\ definitive nest cut transversely.

on the surface in contact with each other (see Halffter, 1977, Fig. 12) 15 to 20 cm from the
dung mass and covered with soil. The female then excavates a groove around them (see Fig. 10)
which is enlarged until the balls are in contact with a minimum of support. Maximum width of
the groove is 7.5 cm; maximum depth, 3.5 cm (see Halffter, 1977, Fig. 13).

This nest is cared for by the female for about 40 days. She makes no attempts to destroy it
but, rather, spends most of her time in the groove, cleaning and maintaining it. Development
lasts about 43 days to teneral adult and another eight days to emergence. The female abandons
the nest shortly before emergence and about a month later re-initiates a new period of
ball-making. This 30 day period is about the same that passes between emergence of the adult
and the beginning of its first nuptial feast; however, much longer times can elapse before it is
begun.

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Once inseminated, females can proceed with successive experimental and definitive nesting
in the absence of a male.

When several females engaged in the nuptial feast occur in the same terrarium, a strong
competition for space ensues. Each female tries to isolate her balls from other females, which
may attack and eat them. Occasionally, fights occur for possession of balls in which each
grapples with the other while lying on her side.

DISCUSSION

Undoubtedly, behavior of Eurysternus adults isolates this taxon from the two main
evolutionary lines of feeding-nesting behavior of the scarabaeines (see Halffter, 1977).
Although the species comprising the genus are morphologically uniform, the few species
studied suggest two very different patterns of nesting behavior. Adults of the species described
here, as well as those of E. mexicanus, display a complex nesting behavior designated Group VI
by Halffter (1977). Another much simpler behavior is displayed by E. foedus,
Guerin-Meneville and a Mexican species (see discussion below). The characteristics of Group
VI, as illustrated by those species considered above are the following:

1) Balls are made only by females during the nuptial feast, the first phase of an elaborate
nesting procedure. Moreover, most are made in large numbers and not rolled.

The nesting behavior of eurysternines, unlike that of scarabaeines, cannot be considered a
derivative of feeding behavior. There are long periods during which feeding occurs but no
ball-making, and there is direct feeding from a dung mass even though balls have been
constructed. Balls can, however, be eaten. The fact that a large number of balls are made and
left on the surface near the dung source (as opposed to being rolled away and buried as is done
by Scarabeini) means that Eurysternus does not profit from the competitive advantages of
rolling behavior; namely, less aggregation and more efficient use of resources. Ball-making by
Eurysternus is, rather, a process related only to reproduction and which is correlated with a
certain stage of ovarial development.

2) Nests are multiple. A multiple nest is a group of brood balls, each with an egg, where
development takes place. Multiple nests cared for by parents (particularly the female) have
arisen three different times, presumably independently, in Scarabaeinae. Although there are
similarities in form and care, of the nest in each group, the way in which each is prepared is
completely different.

In Group III (see Halffter, 1977) a male and female construct an underground chamber
into which dung is brought and from which a female constructs brood balls. In Group V, a
multiple nest arises from an addition of single balls rolled from a dung source and modelled
independently. In Eurysternus , the balls comprising the nest are “selected” from a larger
number prepared during the nuptial feast. Moreover, there are other differences. Females of
Group III prepare a single nest where larval-pupal development is very long; fecundity is very
low. In Groups V and VI, each female prepares several nests ( Eurysternus females prepare
several definitive nests) with intermediate periods of feeding. Even though a male may
participate in nesting in all three groups, it is much more significant in Group III and
non-existent in the definitive nests of Eurysternus (Group VI).

Nevertheless, the most distinctive feature of multiple nests of Eurysternus , and exclusive to

Mating and nesting behavior of Eurysternus

617

them, are the experimental nests, which occur to various degrees in the three species studied
here. Nothing even similar to experimental nests are known in other scarabaeines.

3) Nesting behavior follows the sequence a) nuptial feast, b) experimental nesting, c)
definitive nesting. Females of E. magnus do not build experimental nests. But in E. caribaeus ,
E. magnus and E. mexicanus (Halffter, 1977) experimental and definitive nests are craters
containing several brood balls. In E. balachowskyi the experimental nest is a crater, but the
definitive nest is not (see above). When the brood balls are covered and united with soil by
female E. caribaeus , the definitive nest is established. Care of a definitive nest is similar, but
more elaborate by females of E. balachowskyi. Even though covered by a layer of soil, the
brood balls of E. magnus and E. mexicanus are not united by soil and the balls are continually
turned during care. Temporary care of experimental nest balls by E. balachowskyi females also
includes periodic turning.

Our studies of E. caribaeus show that the state of ovarial development is linked with
reproductive behavior. Maturation of a series of oocytes coincides with nuptial feast; copulation
determines termination of vitellogenesis, beginning of oviposition, and nest preparation.
Nevertheless, unlike other scarabaeines, there is poor synchronization between ovarial
development and nesting behavior. Our belief is that experimental nesting is attributable to a
continuation of oocyte formation . and maturation after a nest has been established. Thus, a
female is influenced by contradictory signals: nesting behavior tends to promote continuance of
nest care, while ovarial function promotes the construction of a new nest. Once the two signals
come into phase, they reinforce each other (which may take an extended period of time), and
definitive nesting ensues. If our hypothesis is true, formation of oocytes must be slowest and
more staggered in E. magnus and most rapid and unrelenting in E. balachowskyi and E.
mexicanus.

If we suppose that reproductive behavior of scarabaeines in general tends toward being a
K-strategy, the strategy is somewhat maladjusted in Eurysternus as compared to other known
groups in that much reproductive effort is lost as a result of experimental nesting.

Since a male joins a female during preparation of nuptial balls, the latter behavior can be
interpreted as a signal to a male that a female is physiologically prepared for copulation and
oogenesis. Perhaps also a large number of nuptial balls is a better inducement for the male’s
parental investment than a small number, as a sort of proof of the female’s nidificatory prowess.
Thus, the nuptial feast may be the result of Darwinian sexual selection (in this case exercised
by the male) in favor of advancing the usual nidificatory ball-making process to a period long
preceding actual nidification. Transition between the early nuptial stage, favored by sexual
selection, and the definitive nesting stage, favored by natural selection, can apparently be
somewhat indefinite and confused in some species, since it is not in itself subject to any direct
selection pressure. The resultant wastefulness of this intermediate experimental stage is
presumably not sufficient to offset the combined selective advantages of the first and last
stages.

Nesting behavior described so far is not universal to E. foedus and a yet unidentified
Mexican species nest in a completely different manner. Females of these species bury shallowly
a compact mass of excrement into which several eggs are laid. Larvae develop freely without
encountering each other or moving around much. The dung mass later contains two or three
tubular spaces created by the developing progeny. Among other differences, there is no
ball-making or nest crater. This nesting pattern is remarkably like that of Onitis caffer
Boheman and O. aygulus (F.), which Halffter and Matthews (1966) assigned to Group I. Such

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behavior, which Halffter and Matthews (1966) considered an evolutionary antecedent to
multiple nests, is no more characteristic of Onitis (and Onitini in general) than it appears to be
for Eurysternus. How common it may be to Eurysternus remains to be seen.

ACKNOWLEDGEMENTS

This paper is the result of a continuous and patient effort followed for many years (the first
terraria were established in 1966) during which we have had the most valuable collaboration
from different people. Pedro Reyes-Castillo and Irma Lopez Guerrero from the Institute de
Ecologia collaborated in the observation of terraria during the first stage. It was possible to
capture E. balachowskyi adults (as well as to gather ecological information and scarabaeines
material from Guyanne) thanks to Gonzalo Halffter’s participation in the expedition to the
Oyapock River (1969) headed by Prof. A. S. Balachowsky who was at that time Chief of the
Laboratoire d’Entomologie of the Museum National d’Histoire Naturelle de Paris.

The E. caribaeus material was captured in the Lacandon Forest by several young
researchers from the Institute de Ecologia: Gustavo Aguirre, Ernestina Fey and Bert
Kohlmann Cuesta.

Histological preparations of ovaries were made by Irma Lopez Guerrero. We thank Prof.
Jacques Carayon and Mile. Dominique Pluot (Laboratoire d’Entomologie, Museum National
d’Histoire Naturelle de Paris) who helped Irma Lopez in the development of the techniques for
the study of scarabaeines ovaries. Dr. Eric G. Matthews (South Australian Museum, Adelaide)
offered useful comments about the manuscript, for which we are grateful.

The English translation from the Spanish manuscript was made by Dr. W. David Edmonds
from the California State Polytechnic University Pomona. As with former works, Edmonds’
collaboration went far beyond a simple translation. We have discussed with our dear friend
each sentence and each word and this has enriched extraordinarily the approach and the ideas
of the authors.

REFERENCES

HALFFTER, G. 1964. La Entomofauna Americana, ideas acerca de su Origen y Distribucion.
Folia Entomologia Mexicana. 6: 1-108.

HALFFTER, G. 1976. Distribucion de los Insectos en la Zona de Transition Mexicana.

Relaciones con la Entomofauna de Norteamerica. Ibid., 35: 1-64.

HALFFTER, G. 1977. Evolution of Nidification in the Scarabaeinae (Coleoptera,
Scarabaeidae). Quaestiones Entomologicae. 13: 231-253.

HALFFTER, G. and E. G. MATTHEWS. 1966. The Natural History of Dung Beetles of the
Subfamily Scarabaeinae (Coleoptera, Scarabaeidae). Folia Entomologia Mexicana.
12-14: 1-312.

HALFFTER, G., V. HALFFTER, and Y. LOPEZ G. 1974. Phanaeus Behavior: food
transportation and bisexual cooperation. Environmental Entomology. 3:341-345.
HALFFTER, G. and V. HALFFTER. 1977. Notas sobre Eurysternus (Coleoptera,
Scarabaeidae, Scarabaeinae). Folia Entomologia Mexicana. 37: 43-86.

HALFFTER, G. and Y. LOPEZ G. 1977. Development of the Ovary and Mating Behavior in

Mating and nesting behavior of Eurysternus

619

Phanaeus. Annals of the Entomological Society of America. 70 (2):203— 21 3.
HEYMONS, R. 1930. Uber die Morphologie des weiblinchen Geschlectsapparatus der
Gattung Scarabaeus.L. Z. Morph. Okol. Tiere. 18: 563-574.

HUERTA, C. 1977. Espermatoforo de Canthon cyanellus cyanellus Lee. (Coleoptera,
Scarabaeidae, Scarabaeinae). Folia Entomologia Mexicana. 38: 13-16.

MATTHEWS, E. G. 1974. A Revision of the Scarabaeinae Dung Beetles of Australia. II.
Tribe Scarabaeini. Australian Journal of Zoology, Suppl. Series 24: 1-211.

Quaest. Ent., 1980, 16 (3,4)

620

Halffter & Halffter

THE LARVAE OF FOUR HYDROPSYCHE SPECIES WITH THE CHECKERBOARD
HEAD PATTERN (TRICHOPTERA: HYDROPSYCHIDAE)

D.H. SMITH & D.M. LEHMKUHL
Department of Biology
University of Saskatchewan
Saskatoon, Saskatchewan
Canada S7N 0W0

Quaestiones Entomologicae
16:625-634 1980

ABSTRACT

Diagnostic characters to distinguish among larvae of four species of Hydropsyche from
Saskatchewan (H. bifida Banks, H. recurvata Banks, H. walkeri Bet ten and Mosely, and H.
bronta Ross) with checkerboard pattern of light and dark areas on the dorsum of the head
include: differences in color of head and pronotum, body proportions, and secondary setation.
A key is provided to larvae of these four species.

Les larves de quatre especes J ’Hydropsyche de la Saskatchewan, caracterisees par un motif en damier de taches pales
et foncees sur la surface dorsale de la tete, se distinguent les unes des autres par des differences dans la coloration de la
tete et du pronotum, dans les proportions du corps, et dans la chetotaxie secondaire. On presente une cle d’ identification
des larves de ces quatre especes.

TABLE OF CONTENTS

Introduction 621

Methods 622

Results 623

Discussion 628

Acknowledgements 628

References 628

Figures 629

INTRODUCTION

Larvae of six hydropsychid species, Hydropsyche bifida Banks, Hydropsyche recurvata
Banks, Hydropsyche walkeri Betten and Mosely, Hydropsyche bronta Ross, Hydropsyche

622

Halffter & Halffter

cheilonis Ross, and Hydropsyche morosa Hagen, have a characteristic checkerboard pattern of
light and dark areas on the dorsum of the head (Figs. 3, 5a). Some individuals have a slightly
modified version of the pattern characteristic of their species (Figs. 5b, 6). Larvae of these six
species are difficult to distinguish and previous taxonomic studies (Ross, 1944; Schuster and
Etnier, 1978) failed to effectively separate them.

Schuster and Etnier, (1978) wrote that three small light spots at the posterior end of the
frontoclypeal apotome distinguish larvae of H. morosa from larvae of the other five species
with the checkerboard head pattern, which either have no light spots, or a single large light spot
at the posterior end of the frontoclypeal apotome. It is doubtful that three spots on the
frontoclypeal apotome is diagnostic, since Mackay (1978) illustrated an H. morosa larva with a
single large light spot.

Mackay (1978) distinguished larvae of H. bronta and H. morosa by differences in head
widths of each instar of the two species, those of H. morosa having a consistently larger mean
head width at each instar. This method is of limited use in normal taxonomic work as it requires
measurement of many specimens from each locality studied. Also, this method may fail to
discriminate between larvae from the same locality if more than two species with the
checkerboard head pattern are represented in the collections.

In Saskatchewan four species of Hydropsyche larvae with checkerboard head pattern were
collected: H. bifida, H. recurvata, H. bronta, and H. walkeri. In this paper we report results of
our study of those taxa.

METHODS

Larval sclerites from pupal cases of reared specimens of H. bifida, H. recurvata, H. bronta,
and H. walkeri were mounted on slides. We found consistent differences, and used them to
identify larvae. Identified larve were then studied for additional diagnostic features. Detailed
study of body setation was facilitated by clearing specimens and mounting various body parts
on slides for study with a compound microscope.

Several measurements were made of heads of larvae of each species. Widths of heads and
measurements of the frontoclypeal apotome (Figure 7) were determined as follows:

1 aa width of apotome at level of anterolateral lobe

2 bb width of apotome just posterad of anterolateral lobe

3 cc width of apotome at level of tentorial pits

4 dd width of apotome at widest portion of posterior part

5 ee width of apotome at level of the pits in posterior part

6 g distance from anterior margin of apotome to lateral pit

7 h distance from lateral pit to anterior margin of tentorial pit

8 k distance from anterior margin of apotome to medial pit H. bifida the anterior

margin gradually bends posterolaterad to meet the anterolateral corner (Figs. 1,

2 & 11). In H. walkeri the anterior margin projects anterolaterad as a small
rectangular lobe (Figs. 3, 4, & 12).

Six ratios calculated from these measurements were used to describe shapes and proportions
statistically, as follows:

1 . Head width/iength of frontoclypeal apotome (HW/FL).

Mating and nesting behavior of Eurysternus

623

2. Width of frontoclypeal apotome at level of tentorial pits/length of
frontoclypeal apotome (FW/FL).

3. Width of frontoclypeal apotome just posterad of anterolateral lobes/ width
of frontoclypeal apotome at level of anterolateral lobes (BL/L).

4. Distance from anterior margin of frontoclypeal apotome to mesal pit on
anterior part of frontoclypeal apotome/distance from anterior margin of
frontoclypeal apotome to lateral pit on anterior part of frontoclypeal
apotome;

5. Distance from lateral pit on anterior surface of frontoclypeal apotome to
anterior edge of tentorial pit/length of frontoclypeal apotome.

6. Width of frontoclypeal apotome at level of pits on posterior part of
frontoclypeal apotome/ width of frontoclypeal apotome at level of widest
part of posterior part of apotome.

Only the first three ratios are discussed further, because they are useful
for discrimination of species. Measurements for ratios BL/L and FW/FL
were taken from mature (fourth and fifth instar) larvae, and from sclerites
extracted from cases of reared pupae. Measurements for the ratio
HW/FL were taken only from mature larvae. All specimens measured are
from Saskatchewan. Range, mean, 1.5 standard deviations (SD) and 95%
confidence limits (CL) were determined for each ratio for each species
(Tables 1-3); these data are illustrated in Figs. 15-17.

RESULTS

We treat features diagnostic for larvae of the four species examined in this study. For more
complete descriptions consult Schuster and Etnier, Etnier (1978).

Color Pattern

Coloration must be used cautiously as a diagnostic feature for larvae of species with
checkerboard head pattern because of variability and overlap.

H. bifida Banks. - Head coloration of H. bifida larvae is quite distinctive compared to head
coloration of larvae of the other three species. In H. bifida, ground color of venter and dorsum
of the head is dark brown in almost all specimens, these dark regions contiguous
posterolaterally (Fig. 1 1) in most specimens. Most specimens of the other three species have a
lateral light area between the dark dorsal and ventral regions of the head (Figs. 12, 13), if
indeed these regions are dark. H. bifida larvae have distinct light spots on sides of the head
(Fig. 11), these spots contrasting with the dark lateral surface. Larvae of the three other species
lack spots on side of head, which contrast as noticeably with ground color of head (Figs. 12, 13)
as in H. bifida. There are also one to three white spots on the dorsal surface of each parietal
sclerite just anterad of seta 17 (Fig. 1). The light region around the eye of most specimens does
not extend posterodorsad towards the margin of the parietal sclerite (Fig. 1), as in H. recurvata
(Fig. 5a), H. bronta (Fig. 6), and most H. walkeri larvae (Fig. 3).

Schuster and EtnierEtnier (1978) noted that many H. bifida larvae are without anterior and
posterior spots on the dorsum of the head. Many Saskatchewan H . bifida larvae lack these

Quaest. Ent. 1980, 16 (3,4)

624

Smith and Lehmkuhl

spots and when the large single spot is absent from the posterior end of the frontoclypeal
apotome, several smaller light spots are evident (Fig. 1).

TABLE I

Variation in the ratio HW /FL for H . bifida, H. recurvata, H. bronta, and H. walkeri

N

Mean

Range

1.5 SD

CL

H.

29

1.139

0.986-1.260

0.071

1.121-1.157

recurvata
H. bifida

33

1.108

1.055-1.175

0.051

1.096-1.121

H. walkeri

42

1.149

1.060-1.300

0.071

1.133-1.164

H. bronta

21

0.959

0.882-1.000

0.047

0.945-0.974

The pronotum has numerous small white spots on each lateral surface (Fig. 14).

H. walkeri Betten and Mosely. - Schuster and EtnierEtnier (1978) reported H. walkeri
larvae with heads almost entirely light in color (as in Fig. 5b), but larvae examined by us have
dark heads with checkerboard pattern on the frontoclypeal apotome (Fig. 3). Some individuals
have, some lack, (Fig. 12) light spots on sides of head; these spots do not contrast as markedly
with ground color of the head as in H. bifida. H. walkeri larvae have a light area at the
posterior end of the frontoclypeal apotome, and there is a distinctive light spot laterad of seta
16 (Fig. 3). Light spots are lacking from the region of the head just anterad of seta 17, and
most specimens have a light area directed posterodorsad from the region around the eye. Most
specimens have a broad, dark stripe along the coronal suture (Fig. 3); this stripe is absent from
or less well developed in larvae of the other three species. Most specimens with the dorsal and
ventral regions of the head dark, have these regions separated by a light lateral area.

Lateral spots on the pronotum are only slightly lighter than ground color.

H. recurvata Banks. - Head coloration of H. recurvata larvae is extremely varied, from
almost entirely dark to almost entirely light (Fig. 5b) (Ross, 1944; Schuster and Etnier,
Etnierl978). Most H. recurvata larvae lack light spots anterad of seta 17 as this area is
occupied by a light area which extends dorsad and posterad from the light region around the
eye (Fig. 5a). In dark specimens of H. recurvata light spots are not evident on the lateral and
dorso-lateral regions of the posterior part of the head (Fig. 13). In lighter larvae some yellow
spots are evident but they do not contrast markedly with ground color of the head. If dorsal and
ventral regions of the head are both dark, they are separated laterally by a light area (Fig. 13)
in most specimens.

Pronotal spots, if evident laterally, are darker than the ground color.

Larvae of Four Hydropsyche species

625

TABLE II

Variation in the ratio FW /FL for H. bifida, H. recurvata, H. bronta, and H. walkeri

N

Mean

Range

1.5 SD

CL

H.

39

0.662

0.608-0.713

0.038

0.654-0.671

recurvata
H. bifida

38

0.651

0.608-0.700

0.032

0.644-0.657

H. walkeri

42

0.647

0.602-0.695

0.035

0.640-0.655

H. bronta

29

0.558

0.522-0.595

0.027

0.551-0.565

H. bronta Ross. - Schuster and Etnier Etnier(1978) described two forms of H. bronta ,
based on differences in larval head patterns, from different regions of their study area. The
Central Form has the typical checkerboard head pattern, but the Appalachian Form has a
transverse striped head pattern (Fig. 6). Adults associated with the two larval forms are
indistinguishable. In Saskatchewan both larval forms were collected, often from the same river.
It is likely these two color forms are conspecific variants.

Small light spots are evident laterally on heads of some H. bronta larvae, but most larvae
lack them. The light area around the eyes of most larvae is extended posterodorsad to the
region anterad of seta 17 (Fig. 6). Ventral and lateral surfaces of the head are predominantly
light. On each parietal sclerite of many larvae is a brown spot near the ventral ecdysial line and
another on the ventrolateral surface in the vicinity of the stridulatory surface.

Pronotal sclerites lack contrasting dark or light spots laterally.

Head Setation

Head setation is most readily observed on cleared specimens mounted on slides. Head
capsules of hydropsychid larvae possess a rich secondary setation, these setae being greatly
modified in many species. The Hydropsyche larvae examined in this study have three main
types of secondary setae on the head. The first is stout, dark, peg-like setae prominent on much
of the dorsal and posterolateral regions of the parietal sclerites, and also on the frontoclypeal
apotome of larvae of some species. The second type is fine setae present for most specimens on
anterodorsal and posterodorsal regions of the parietal sclerites and on the frontoclypeal
apotome. Larvae of some Hydropsyche species have setae intermediate between these first two
types. The third type of secondary setae is along the anterior margin of the frontoclypeal
apotome. These setae are extremely small with their blunt apical ends minutely divided.

Information about setation for abraded heads can be gained by determining size and
number of sockets left where setae were attached. Sockets at bases of peg-like setae are larger

Quaest. Ent. 1980, 16 (3,4)

626

Smith & Lehmkuhl

TABLE III

Variation in the ratio BL/L for H. bifida, H. recurvata, H. bronta, and H. walkeri

N

Mean

Range

1.5 SD

CL

H.

46

0.93

0.889-0.959

0.026

0.925-0.935

recurvata
H. bifida

39

0.892

0.84-0.944

0.036

0.884-0.900

H. walkeri

42

0.903

0.857-0.943

0.029

0.897-0.909

H. bronta

28

0.857

0.814-0.89

0.03

0.849-0.864

than those of the fine setae. Number of sockets in the rubbed area indicate number of setae
previously present in that region.

H. bifida Banks. - Larvae of H. bifida have many long, fine setae on the posterior part of
the frontoclypeal apotome, and on the region of each parietal sclerite laterad of the posterior
end of the frontoclypeal apotome (Figs. 8, 11). Peg-like setae are absent from the posterior part
of the frontoclypeal apotome (Figs. 1, 8).

H. walkeri Betten and Mosely. - Numerous long, fine setae are on the posterior part of the
frontoclypeal apotome, and on the region of each parietal sclerite laterad of the posterior end of
the frontoclypeal apotome (Figs. 8, 12). Peg-like setae are absent from the posterior part of the
frontoclypeal apotome (Fig. 3).

H. recurvata Banks. -

The central portion of the posterior part of the frontoclypeal apotome has few, fine, very
short setae (Figs. 9, 13). Fine setae are more abundant on the parietal sclerites laterad of the
posterior end of the frontoclypeal apotome. A few peg-like setae are present on the posterior
part of the frontoclypeal apotome (Figs. 5a, 5b, 9).

H. bronta Ross. - Like H. bifida larvae, those of H. bronta have numerous fine setae on the
posterior part of the frontoclypeal apotome (Fig. 10), although these setae are shorter in H.
bronta. There are also peg-like setae, and setae which are intermediate in thickness between the
fine and peg-like setae, on this region of the frontoclypeal apotome, and on the parietal sclerites
in the region laterad of the posterior end of the frontoclypeal apotome. Most peg-like setae on
heads of H. bronta larvae are more acuminate than in the other three species.

Larvae of Four Hydropsyche species

627

Shape of Head and Head Sclerites

Based on shape of head and frontoclypeal apotome, the four species considered in this study
are arranged in two groups. In Group I head width of almost all specimens is greater than
frontoclypeal apotome length, and the frontoclypeal apotome is much wider in relation to its
length than in Group II. In Group II width of head is equal to or less than length of the
frontoclypeal apotome, and the latter is much narrower in relation to its length than in Group I.
Larve of these four species differ in values for ratos HW/FL (Fig. 15) and FW/FL (Fig. 16).

The ratio HW/FL (Fig. 15) shows that heads of H. bronta larvae are much narrower in
relation to length of frontoclypeal apotome than are heads of the other three species. The ratio
FW/FL (Fig. 16) indicates that H. bronta larvae have much longer, narrower frontoclypeal
apotomes than do larvae of the other three species. Based on these ratios it is clear that three of
the four species studied, H. bifida , H. walkeri, and H. recurvata , belong to Group I while only
H. bronta belongs to Group II. We calculated values for ratios HW/FL and FW/FL from a
drawing of the larva of H. morosa in Mackay (1978). Values obtained indicate that H. morosa
probably belongs in Group II, if the drawing accurately represents the species.

Among the four species studied there are differences in relative size of anterolateral lobe of
frontoclypeal apotome. In H. bronta these lobes are prominent while in H. recurvata they are
only slightly developed. In H. bifida and H. walkeri development of these lobes is intermediate
between those of H. bronta and H. recurvata. The ratio BL/L (Fig. 17) illustrates the
difference in development of the anterolateral lobes of the frontoclypeal apotome among the
four species.

Hydropsyche bifida and H. walkeri larvae differ in shape of the anterior part of the
frontoclypeal apotome. In H. walkeri larvae each lateral margin of the anterior part bulges
outward (Figs. 3, 4), while in most, but not all H. bifida larvae the margin is straight (Figs. 1,
2). Larvae of these species also differ in the shape of anterior margin of the frontoclypeal
apotome. In H. bifida the anterior margin gradually bends posterolaterad to meet the
anterolateral corner (Figs. 1, 2 & 1 1). In H. walkeri the anterior margin projects anterolaterad
as a small rectangular lobe (Figs. 3, 4, & 12).

Key to Species

la Ratio FW/FL 0.522 -0.595 H. bronta

lb Ratio FW/FL 0.602 -0.713 2

2a (lb) Dorsum of head with numerous long, fine setae on middle of posterior part of
frontoclypeal apotome (Figs. 8, 11, 12); no peg-like setae on posterior part of
frontoclypeal apotome (Figs. 1, 3, & 8); side of head with (Fig. 11) or without

(Fig. 12) light spots 3

2b Middle of posterior part of frontoclypeal apotome with few short, fine setae

(Figs. 9, 13); peg-like setae on posterior part of frontoclypeal apotome (Fig. 5b);

side of head without contrasting light spots (Fig. 13) H. recurvata

3a (2a) Anterolateral margin of frontoclypeal apotome gradually curved posterad to

anterolateral corner of apotome (Figs. 1, 2, 1 1) H. bifida

3b Anterior margin of frontoclypeal apotome projected forward as small

rectangular lobe near each anterolateral corner of apotome (Figs. 3, 4, & 12) H.
walkeri

Quaest. Ent. 1980, 16 (3,4)

628

Smith & Lehmkuhl

DISCUSSION

Diagnostic features described above must still be tested on populations of these species in
other parts of North America for study of larvae with checkerboard head pattern is still
incomplete. Search for new and perhaps better features for identification for these species must
continue, preferably with inclusion of all species with this head pattern. We believe our results
will be useful to anyone undertaking this task.

ACKNOWLEDGEMENTS

Support for this study was provided by a National Research Council of Canada grant to
D.M. Lehmkuhl. The senior author thanks the Institute for Northern Studies for the
scholarship which enabled him to study Saskatchewan caddisflies.

We thank David Wong for his skillful preparation of the graphs.

REFERENCES

Mackay, R.J. 1978. Larval identification and instar association in some species of Hydropsyche
and Cheumatopsyche (Trichoptera: Hydropsychidae). Annals of the Entomological
Society of America 71: 499-509.

Ross, H.H. 1944. The caddisflies, or Trichoptera, of Illinois. Bulletin of the Illinois Natural
History Survey 23: 1-326.

Schuster, G.A. and D.A. Etnier. 1978. A manual for the identification of the larvae of the
caddisfly genera Hydropsyche Pictet and Symphitopsyche Ulmer in eastern and central
North America (Trichoptera: Hydropsychidae). United States Environmental

Protection Agency Report No. 600/4-78-060. 129 pp.

Larvae of Four Hydropsyche species

629

Figs. 1-4. Fig. 1. H. bifida head, dorsal aspect; Fig. 2. H. bifida frontoclypeal apotome; Fig. 3. H. walkeri head, dorsal
aspect; Fig. 4. H. walkeri frontoclypeal apotome showing bulge on side of front part of apotome (bl) and rectangular
lobe on lateral portion of anterior margin (rl).

Quaest. Ent. 1980, 16 (3,4)

630

Smith & Lehmkuhl

Figs. 5-7. Fig. 5a. H. recurvata head, dorsal aspect; Fig. 5b. H. recurvata head, dorsal aspect, showing anterior part of
frontoclypeal apotome (af), posterior part of frontoclypeal apotome (pf) and parietal sclerite (pa); Fig. 6. H. bronta
head, dorsal aspect; Fig. 7. Hydropsyche frontoclypeal apotome (schematic) showing locations where measurements
were taken; also anterolateral lobe (r), tentorial pit (t), medial pit on anterior part (v), lateral pit on anterior part (z)
and pit on posterior part (y).

Larvae of Four Hydropsyche species

631

Figs. 8-13. Fig. 8. H. bifida dorsum of head showing fine setae (f), peg-like setae (p), and frontoclypeal suture (x); Fig.
9. H. recurvata dorsum of head showing peg-like seta (p); Fig. 10. H. bronta dorsum of head showing peg-like seta (p);
Fig. 11. H. bifida head, lateral aspect, showing fine setae (f); Fig. 12. H. walkeri head, lateral aspect showing
rectangular lobe (rl); Fig. 13. H. recurvata head, lateral aspect, showing fine setae (f);

Quaest. Ent., 1980, 16(3,4)

632

Smith & Lehmkuhl

Fig. 14.-Thoracic sclerites of Hydropsyche bifida.

Larvae of Four Hydropsyche species

633

H . bifida ~~L- L

H. walkeri
JH. bronta

Fig. 15

h-

88

I - J-

96 1.04

HW/FL

H-

1.1 2

H-

1.2

H 1

1.28 1.36

JH. recurvata
JH. bifida
JH. waikeri
H. bronta

Fig. 16

I 1— — H 1 1 f

.52 .56 .6 .64 .68 .7

FW/FL

-H

.74

JH . recurvata
JH . bifida
it- walkeri
H . bronta

- ■■ 1 1* 1

r l

Fig. 17

.81

1 — t—

85 .89

BL/L

H-

93

+“

97

Figs. 15-17. Fig. 15. Variation in the ratio HW/FL for H. bifida , H. recurvata, H. bronta, and H. walkeri. Data for
each species is represented as follows: range, by basal horizontal line, mean by medial vertical line, confidence limits by
dark box and 1.5 standard deviations on each side of the mean by the clear box. Fig. 16. Variation in the ratio FW/FL
for H. bifida, H. recurvata, H. bronta and H. walkeri ; for explanation, see caption of Fig. 15; Fig. 17. Variation in the
ratio BL/L for H. bifida, H. recurvata, H. bronta and H. walkeri. For explanation see caption of Fig. 15.

Quaest. Ent. 1980, 16 (3,4)

634

Smith & Lehmkuhl

ANALYSIS OF TWO PROBLEMATIC NORTH AMERICAN CADDISFLY SPECIES:
OECETIS A VARA (BANKS) AND OECETIS DISJUNCTA (BANKS) (TRICHOPTERA:

LEPTOCERIDAE)

D.H. Smith and D.M. Lehmkuhl
Department of Biology
University of Saskatchewan
Saskatoon, Saskatchewan
Canada

S7N0W0

Questiones Entomologicae
16:641-656 1980

ABSTRACT

Oecetis disjuncta (Banks) has, since 1944, been regarded as possibly conspecific with
Oecetis avara (Banks). We propose here that these two forms are specifically distinct. Adults,
larvae, and pupae of both species are described. In Saskatchewan O. avara lives in southern
and central regions, while O. disjuncta inhabits central and northern regions. Immatures of
both species inhabit boreal streams, but those of O. avara also inhabit the main branches of
the Saskatchewan river system. Because specimens of O. disjuncta may, previously, have been
misidentified as O. avara, some published distribution records for the latter may not be
correct. Collection data for specimens examined in this study indicate that both species are
widely distributed in North America.

Depuis 1944, on considerait Oecetis disjuncta (Banks) comme un synonyme possible ^’Oecetis avara (Banks). Nous
proposons qu’O. disjuncta, bien que morphologiquement similaire a O. avara, soil considere comme une espece distincte.
Nous decrivons les adultes, les larves, et les pupes des deux especes. En Saskatchewan, O. avara occupe les regions du
centre et du sud, alors qu’O. disjuncta se trouve dans les regions di cemtre et du nord. Les immatures des deux especes
habitent les affluents secondaires boreaux, mais ceux d’O. avara se trouvent aussi dans les branches principales du
bassin de la riviere Saskatchewan. Etant donne qu’suparavent, des specimens d’O. disjuncta pourraient avoir ete
identifies comme O. avara, certaines mentions publiees au sujet de la repartition geographique de cette derniere
pourralient etre erronees. Les notes de collection des specimens examines au cours de cette etude indiquent que les deux
especes sont largement repandues en Amerique du Nord.

TABLE OF CONTENTS

Introduction 636

Descriptions 637

Oecetis disjuncta (Banks) 638

636

Smith & Lehmkuhl

Oecetis avara (Banks) 641

Discussion 643

Disposition of Material 644

Acknowledgements 644

References 644

Figures 646

INTRODUCTION

While studying Saskatchewan-collected males of Oecetis avara (Banks), we discovered that
two distinct color forms are recognizable: one with dark brown body and wings (dark form);
and another with yellow body and wings (light form). In central Saskatchewan, where both
forms occur, the main emergence of dark form adults is earlier in the year than that of light
form adults. Comparison of male genitalia of the two forms revealed differences in structure of
claspers and aedeagus. In the dark form, claspers lack a prominent ventrocaudal lobe (Fig. 1),
and the aedeagus, in caudal aspect, is symmetrical (Figs. 5, 7). In the light form, claspers
possess a prominent ventrocaudal lobe (Fig. 3), and the aedeagus is asymmetrical, in caudal
aspect (Figs, 6, 8). Differences in form of male genitalia between two forms of putative O.
avara associated with differences in general body coloration, and timing of adult emergence,
suggested to us that we were studying not just variants of a single species, but two distinct
species. We then searched for differences in other life stages.

We were able to associate adult females, larvae, and pupae with males of the dark and light
forms, respectively, and morphological differences were found which discriminate between
them.

We also examined ‘0. avara’ specimens loaned to us by Dr. G. B. Wiggins of the Royal
Ontario Museum (ROM). These had been collected from 1 1 North American localities outside
Saskatchewan. The dark form was recorded from eight localities, the light form from three;
there was no overlap. Adults of dark and light forms from the 1 1 localities are morphologically
consistent with adults of their equivalents from Saskatchewan. Presence of dark and light forms
in collections of ‘0. avara’ from localities outside of Saskatchewan indicates that these forms
are not local variants, restricted to Saskatchewan, but both are widely distributed in North
America. This further strengthened our conclusion that the two forms are distinct species.

The type specimens of 0. avara and 0. disjuncta

The two species recognized by us could not be named, based on published information. 0.
avara belongs to the disjuncta species group of the genus Oecetis. The disjuncta group contains
three species, 0. elatus Denning and Sykora, 0. avara (Banks), and 0. disjuncta (Banks).
Taxonomic status of 0. disjuncta has remained in doubt since Ross (1944) suggested that this
form might be conspecific with 0. avara. Drawings of the male genitalia of 0. avara (Ross,
1944), and of 0. disjuncta (Banks, 1920) indicate that males of both species have a prominent
ventrocaudal lobe on the clasper, but that the dorsal region of the clasper in 0. disjuncta is
much larger than it is in 0. avara. Ross (1938), however, stated that the male genitalia of the
type specimens of 0. avara and 0. disjuncta were very similar, which suggested to us that

Two problematic North American caddisfly species

637

Banks’ (1920) drawing of the clasper of O. disjuncta might be inaccurate.

We examined the genitalia of male type specimens of O. avara and O. disjuncta , and found
that each clasper of the holotype of O. avara has a prominent ventrocaudal lobe. The clasper of
the lectotype male of O. disjuncta , however, lacks a prominent ventrocaudal lobe, although
Banks’ (1920) drawing of the genitalia of O. disjuncta illustrated this lobe. Also, the dorsal
portion of the clasper of the type speciman of O. disjuncta is not markedly enlarged, although
Banks drawing indicated it to be so. The aedeagus of the O. avara holotype is damaged and
its structure could not be determined. The aedeagus of the type specimen of O. disjuncta is
symmetrical, in caudal aspect.

Our study of the genitalia of the two forms revealed that male specimens were most
effectively discriminated between by differences in aedeagal structure. Differences in clasper
shape were useful for separating most specimens, but not for discriminating between a few
specimens which had claspers intermediate in structure. Form of claspers and aedeagus of the
O. disjuncta lectotype resemble those of males of the dark form. On this basis we concluded
that the dark form was conspecific with O. disjuncta. Although the aedeagus of the O. avara
holotype is damaged, and could not be compared to males of the light form, the claspers, with
their prominent ventrocaudal lobes, leave no doubt that O. avara is conspecific with the light
form of our study. We conclude that O. disjuncta and O. avara , are taxonomically distinct.

DESCRIPTIONS

This section is divided into two parts. In the first, selected morphological features of adults,
larvae, and pupae of O. disjuncta and O. avara are discussed, to facilitate accurate
identification of specimens and to provide comparative information about interspecific variation
in certain structures. The second part provides detailed descriptions of adults, larvae, and pupae
of O. disjuncta and O. avara.

Descriptions are based on examination of a large number of specimens in our collection
taken throughout the province of Saskatchewan, as well as some from the ROM.

Comparison of selected features

Adults. - Although most adults of O. avara are yellow, and adults of O. disjuncta dark
brown, some are intermediate. The tibial spur formula of O. disjuncta and O. avara is 1,2,2
which distinguishes these two species from the closely related O. elatus which, according to
Denning and Sykora (1966), has a spur formula of 1,2,3.

The only feature of the male genitalia which is consistently different in the two species is
structure of the aedeagus. In caudal aspect, the aedeagus of O. disjuncta is symmetrical (Figs.
5, 7), while in O. avara it is asymmetrical (Figs. 6, 8). There are no sclerotized areas on the
apico-dorsal surface of the aedeagus in O.disjuncta (Figs. 5, 7), while in O.avara sclerotized
areas are present on that region (Figs. 6, 8). Form of the claspers differs in the two species.
Most males of O. disjuncta lack a prominent ventrocaudal lobe (Fig. 1), while males of O.
avara have such a lobe (Fig. 3). However, in both species, some males have claspers that are
nearly intermediate. Ventral margins of bases of claspers in the normal resting position are
more widely separated in O. avara (Fig. 13)than they are in O. disjuncta (Fig. 12) The median
process of tergum X consists of one (Fig. 10) or two (Fig. 9) lobes in O. disjuncta. Since both
variants are represented in many series of males collected on the same date at the same locality,

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Smith & Lehmkuhl

and since no other morphological differences were detected between males with one or two
lobes, we conclude that these variants are conspecific. In males of O. avara examined in this
study the median process of tergum X is a single lobe (Fig. 11).

We identified some morphological differences between female genitalia, but it is uncertain if
these will distinguish between all specimens. Sternum IX of females of both species has a
similar pattern of coloration but, in O. disjuncta, the darkened area is much darker (Fig. 14)
than in O. avara (Fig. 15). Body coloration is varied; possibly specimens will be found in which
sternal color is intermediate, although we have not seen such intermediates. The lateral sclerite
of segment IX also differs in shape in the two species. In O. avara (Fig. 17) the caudal margin
of this sclerite is produced as a prominent ventrocaudal lobe, projected beyond the caudal
margin of sternum IX in ventral aspect (Fig. 15). In O. disjuncta the ventrocaudal lobe of the
lateral sclerite of segment IX is slightly developed or absent (Fig. 16) and, in ventral aspect
(Fig. 14), this lobe does not project beyond the caudal margin of sternum IX. However, some
females of O. disjuncta have a prominent ventrocaudal lobe on the lateral sclerite of segment
IX. Although some females of O. avara and O. disjuncta may prove difficult to identify, most
specimens can be readily separated using the features discussed above.

Larvae. - Larvae of O. avara and O. disjuncta are morphologically similar and, currently,
only mature larvae of these two species can be assigned to species. The ventral apotome of the
head capsule is much narrower, relative to its length, in O. disjuncta (Fig. 23) than in O.avara
(Fig. 24). Difference in shape of the ventral apotome in larvae of these two species is reflected
by difference in value of the width/length ratio for the ventral apotome of each species. Values
for O. disjuncta are 1.7 - 2.8 (x = 2.23) and for O. avara 3.14 - 8.00 (x =4.48). Head color
differs between most specimens of O. avara and O. disjuncta but intermediate specimens were
observed for both species. The dorsum of the head capsule in most specimens of O. disjuncta is
brown, marked by darker muscle scars (Figs. 18, 21), while in O. avara the head capsule is
yellow, with muscle scars not contrasted with the ground color (Figs. 19, 22). In O. disjuncta
larvae the dorsal setae of the distal articles of the thoracic legs (Figs. 33, 34) tend to be longer
relative to the width of the parent article than are the equivalent setae in O. avara larvae (Figs.
35, 36).

Pupae. - Pupae of O. avara and O. disjuncta are morphologically very similar. The only
distinguishing feature is relative length of four setae on front of head. In O. disjuncta (Fig. 38)
the ventral pair of setae are shorter than the dorsal pair. In O. avara these four setae are
subequal (Fig. 39).

Detailed descriptions

Oecetis disjuncta (Banks)

Oecetina disjuncta Banks , 1920: 351 (Type locality: California, Arroyo Seco Canyon, San
Gabriel Mountains).

Adults. - Body and wings brown, legs yellow. Forewing with dark patches on stigma, at base
of discoidal and of thyridial cells, on chord, at branching point of Cul, at juncture of anal and
cubital veins, and at extremities of veins extended to wing margin. Tibial spur formula 1,2,2.
Males 1 1-12 mm, females 10 - 12 mm in length.

Two problematic North American caddisfly species

639

Male abdominal segment IX annular; in lateral aspect (Fig. 1), dorsal half wider than
ventral half, numerous setae on lateral surface; sternum, ventrally (Fig. 12), with large
membranous area; cercus short, tubular (Fig. 1) or elongate with ventral surface concave.
Clasper (Fig. 1), in lateral aspect, with dorsal margin rounded, posterior margin shallowly
emarginate, ventrocaudal lobe reduced or absent; few specimens with posterior margin
emarginate and ventrocaudal lobe present; ventromesal margins of both claspers, close together
(Fig. 12). Segment X with pair of lightly sclerotized, triangular lateral lobes; mesal process of
one (Fig. 10) or two (Fig. 9) lobes (in dorsal aspect), apex of lobes entire (Fig. 9) or incised
(Fig. 10). Aedeagus, in lateral aspect (Fig. 2), with distal half directed ventrad; in caudal
aspect (Figs. 5, 7), symmetrical, posterodorsal surface entirely membranous; internal
sclerotized ring symmetrical in caudal aspect (Fig. 7).

Female genitalia with lateral sclerite of segment IX narrow (Fig. 16); ventrocaudal lobe
absent or slightly developed, not extended beyond caudal margin of sternum IX (Fig. 14); few
specimens with caudal lobe well developed, extended beyond caudal margin of sternum IX.
Latter with ventral surface in form of raised, flattened, oval area (Fig. 14); pattern on oval area
darker and more distinct than in O. avara, oval area bordered by dark area anteriorly and
laterally. Cercus, in lateral aspect (Fig. 16), evenly rounded apically, short, not extended
beyond segment X. Clasper, in lateral aspect (fig. 16), rectangular, with ventral and dorsal
margins thickened. Segment X mostly membranous; ventrocaudal margin sclerotized, extended
beyond rest of segment. Bursa copulatrix as in Figure 14.

Larva. - Head with dorsum dark yellow to brown, marked by darker spots (Figs. 18, 21);
anterolateral region brown (Fig. 21), area about eyes white; lateral and posterolateral regions
white except scattered brown spots (Fig. 21) and large brown area in middle of gena with few
darker spots; venter of head (Fig. 23) light except brown ventral apotome, pair of brown
triangular patches posterad of ventral apotome, and dark rim around occipital foramen.
Cephalic seta 13 ventrad of midpoint between setae 14 and 15 (Fig. 18); seta 16 directly
anterad of seta 17. Frontoclypeal apotome (Fig. 18) darkest laterally; posterior part with two
large brown spots, one behind other, subdivided in some specimens; anterior part of
frontoclypeal apotome with two pairs of brown spots; linear pale area between each
anterolateral corner and rest of apotome (Figs. 18, 20). Each parietal sclerite (Fig. 18) with
four brown spots along dorsomesal margin; more brown spots near margin with subocular line.
Structure of labrum as in O. avara , spines of ventral comb as in Figure 29. Mandibles (Fig. 26)
each with single blade, mesal margin basad of subapical teeth of most specimens without
serrations. Plate on dorsal surface of submentum V-shaped (Fig. 25), with point of V directed
caudad. Ventral apotome (Fig. 23) nearly as wide as long (width/length ratio values range
1.7-2. 8; (x=2.23; n = 40); lateral margins of apotome rounded, anterolateral extensions
present.

Pronotum (Fig. 32) with light anterior transverse band; middle with light brown transverse
band; posterior region light, marked by few brown spots. Each mesonotal sclerite (Fig. 32)
brown anteriorly, lighter posteriorly; one seta near anteromesal corner, 16 to 21 setae along
anterior and lateral margins, three setae on middle of sclerite. Metanotum (Fig. 32) with sa2 of
one to two setae; sa2 of one to three setae. Trochantin of propleuron (Fig. 30) with three to six
setae on dorsal surface. Mesopleuron with single seta on each of episternum and epimeron.
Metapleuron (Fig. 32) with as many as eight setae on episternum, one seta on epimeron.
Foreleg (Fig. 33) without secondary setae on ventral surface of basal part of trochanter;
anterior surface of apex of trochanter with two stout, spine-like setae on ventral surface, two

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Smith and Lehmkuhl

setae near distal oblique margin; setae on dorsal surface of femur longer relative to femur width
than in O. avara ; tibia with single spine-like seta on distal portion of anterior surface; claw as
in O. avara. Structure of midleg and hindleg (Fig. 34) similar to O. avara except setae on
dorsal surfaces of femur and tibia of these legs longer relative to width of article than in O.
avara. Mesosternum without setae. Metasternum with two or three setae (in few individuals).

Abdomen with anterior gills on dorsum of segments II to VII and venter of segments II to
VI; pair of pleural gills on segment II; gills absent from lateral lobes of segment I. Segment I
with two groups of hooked spines at tip of median dorsal lobe (Fig. 32), each group wider than
long. Segment IX with single seta near each lateral margin; posterior margin with six long and
four short setae (Fig. 31). Hairs and spines sparse on membranous caudal surface of abdomen.
Claw of anal proleg with two dorsal denticles.

Mature larvae 7-8 mm in length.

Pupa. - Labrum (Fig. 40) rounded, triangular; anterior margin extended anterad mesally as
short, acute lobe. Mandibles (Fig. 37) with distal quarter of length directed slightly mesad;
mesal margin with teeth in region of bend, fine serrations basad and distad of teeth; two lateral
setae about equal in length, in line along lateral margin of mandible. Frons with two pairs of
setae; ventral pair much shorter than dorsal pair (Fig. 38).

Abdomen with anterior tergal plates on segments III to VII dark brown (Fig. 41), each with
three to five teeth; posterior part of each plate directly posterad of midline of anterior part of
plate in most specimens; anterior part of each plate oval, with anterior margin rounded,
anterior part rounded-triangular in few specimens; posterior tergal plate of segment V oval,
teeth inserted anterad of thin lighter area near posterior margin of plate. Lateral sclerotized
bars on each side of terga II to VIII T-shaped (Fig. 43), bars of most specimens thicker than in
O. avara. Anal rod as in Figure 45.

Pupae of both sexes 8 mm in length.

Larval and pupal cases. - Larval cases of O. disjuncta are tubular, curved slightly
posteriorly, and composed of sand grains (Figs. 46, 47). Cases of younger larvae (Fig. 46) are
more markedly tapered and curved than those of mature larvae (Fig. 47). The pupal case (Fig.
48) is similar to that constructed by mature larvae except that anterior end of pupal case has a
prominent flange. Pupal cases of O. avara do not have this prominent flange at the anterior end.

Bionomics. - Larvae of O. disjuncta occur primarily in fast flowing boreal streams. Adults
were collected in Saskatchewan from June 16 to June 21, and pupae from May 23 to July 17.
There is a single generation per year, the larvae overwintering. Adult emergence periods of O.
avara and O. disjuncta overlap but the peak emergence for O. disjuncta occurs earlier than for
O. avara.

Distribution. - O. disjuncta is recorded from Saskatchewan in Canada, and from Michigan,
South Dakota, Utah, Oregon and California in the United States. In Saskatchewan, O.
disjuncta is restricted to rivers in the central and northern regions of the province (Fig. 50).

Material examined. - SASKATCHEWAN Cold R. at Cold L., 10. VII. 1975, 1 larva-30.VIII.1976, 2 larvae; Mistohay
Cr. at Hwy. 224, 12. VIII. 1975, 3 larva-23.V.1975, 1 larvae, 2 3 pupae; Arsenault R. at Hwy. 104, 23. V. 1975, 4 pupae, 6
larvae; Englishman R. at Hwy. 26, 2.V.1977, 4 larvae-22.V.1975, 3 2 pupae-12.VIII.1975, 8 larvae-21. VIII. 1977, 2
larvae-29. VIII. 1976, 14 larvae; Waterhen R. at Hwy. 26, 4. V. 1977, 9 larvae-23.V.1975, 2 larvae-25. VII. 1976, 29 larvae;
Waskesiu L., 4. VII. 1940, 1 2 ; Weyakwin R. at Hwy. 2, 29. VII. 1976, 5 larvae; Montreal R., 8. V. 1960, 10
larvae-7.VI.1960, 1 larva-22. VI 1 1. 1960, 3 larvae; Caribou Cr. at Hwy. 120, 6.V1II.1976, 5 larvae-29.V.1977, 3 2
pupae-12.IV.1977, 1 larva-17.VI.1976, 4 <5 -1 1. VIII. 1977, 1 larva-15.VII.1976, 3 larvae; McDougal Cr. at Hwy. 120,
31. V. 1977, 3 larvae, 5 pupae-5.V.1977, 6 larvae-17.VI.1977, 2 <3 -22.VI.1977, 2 larvae, 2 2 pupae, 1 <3 pupa-7.VIII.1976,
9 larvae-16.VI.1976, 15 <5 -18.VI.1976, 1 2 ,15 3 -7.VII.1977, 1 3 -21. IX. 1976, 13 larvae; Puskwakau R. at Hwy. 106,
10. VI. 1975, 1 larva-17. VII. 1975, 1 3 pupa-6. VIII. 1976, 6 larvae; Cub Cr. at Hwy. 106, 29. V. 1975, 1 larva; Torch R. at
Hwy. 106, 21. IX. 1976, 3 larvae; MacKay Cr. at Hwy. 2, 5. VI. 1974, 3 larvae-7.VI.1977, 12 pupa-8. VI. 1977, 1 3 pupa, 1 2

Two problematic North American caddisfly species

641

pupa-21. VI. 1976, 1 2 -30.V1I.1976, 9 larvae-18.VIIl.1976, 11 larvae; Waddy R. at Hwy. 102, 3.V11.1975, 2 2 ; Creek
at mi. 37 of Hwy. 105, 17. VIII. 1976, 8 larvae; River at mi. 85 of Hwy. 102, 7. VIII. 1972, 2 larvae;
CALIFORNIA-stream near Oregon City, Butte Co., 1. VI. 1961, 1 <3(ROM); OREGON-South Umpqua R. at mouth
of Coffee Cr„ Rt. 138, s. Kellogg, Douglas Co. 7. VI. 1968, 2 6 (ROM); Lake Co., Deep Creek 56, 13. VI. 1978, 2 <5
(ROM); Lake Co. Twenty-mile Cr., Site 6 + 7, 6. VI. 1978, 14 3(ROM); SOUTH DAKOTA-stream in Spring Cr.
Campground, Black Hills near Rapid City, 17.VI.1969, 2 <3 (ROM); Horse Cr. at Sheridan L., Pennington Co.,
8. VI. 1961, 5 3 (ROM); MICHIGAN- Pellston, Emmet Co., west branch Maple R. at Rt. 31, 13. VI. 1972, 2 larvae, 1
pupa (ROM); UTAH- Bear R., East Fork For. Campground, Summit Co., 12. VI. 1961, 6 , 2 (ROM).

Oecetis avara (Banks)

Setodes avara Banks, 1895: 316. (Type locality: Sherbrooke, Canada). Oecetina avara
Banks, 1899: 214.

Adults. - Body and wings yellow to light brown, legs yellow. Forewing with spots as in O.
disjuncta, spots sometimes absent in females. Tibial spur formula 1,2,2. Males 9.5-11 mm,
females 7-10 mm in length.

Male genitalia with segment IX annular; in lateral aspect (Fig. 3), dorsal half wider than
ventral half, setae on lateral surface not as numerous as in O. disjuncta', sternum, in ventral
aspect (Fig. 13), with large membranous area; cercus (Fig. 3) with dorsal surface convex,
ventral surface concave. Clasper (Fig. 3) with dorsal margin rounded, posterior margin deeply
incised, shallowly incised in few specimens; ventrocaudal lobe prominent, not as prominent in
few specimens; ventromesal margins of both claspers widely separated at base (Fig. 13).
Segment X (Fig. 11) with pair of lightly sclerotized triangular lateral lobes; mesal process
composed of single elongated, sclerotized lobe, apex of lobe entire (Fig. 1 1) or shallowly incised
(Fig. 10). Aedeagus, in lateral aspect (Fig. 4), curved posteroventrad; in caudal aspect (Figs. 6,
8) aedeagus asymmetrical, apicodorsal surface with distinct sclerotized areas; inner sclerotized
ring asymmetrical (Fig. 8).

Female genitalia with lateral sclerite of segment IX, in lateral aspect (Fig. 17), narrow, with
prominent ventrocaudal lobe; lobe extended beyond caudal margin of sternum IX (Fig. 15);
latter with ventral surface in form of raised, flattened oval area (Fig. 15); pattern on oval area
much lighter and less distinct than in O. disjuncta ; oval area bordered by dark area laterally
and anteriorly. Cercus, in lateral aspect (Fig. 17), rounded, triangular, not extended beyond
segment X. Claspers and segment X (Fig. 17) as in O. disjuncta. Bursa copulatrix as in Figure
15.

Larva. - Dorsum of head yellow (Fig. 19); muscle scars indistinct; darker in color and
contrasted with ground color of head in few specimens. Posterolateral and posterodorsal areas
of head white (Fig. 22). Cephalic seta 13 (Fig. 19) directly below midpoint between seta 14 and
15; seta 17 directly posterad of seta 16. Frontoclypeal apotome with linear pale area between
each anterolateral corner and rest of sclerite (Figs. 19, 20). Labrum (Fig. 28) with convex lobe
on either side of mesal indentation; margin of lobe entire; numerous secondary setae on anterior
portion of dorsum; venter with pair of setae near lateral margin and single seta near anterior
margin on each side, some small spine-like hairs near anterior seta on left side, prominent
comb of spines near posterior margin, spines as in Figure 29. Mandibles (Fig. 27) single bladed,
prominent serrations on mesal surface basad of subapical teeth. Sclerite on dorsal surface of
submentum V-shaped or U-shaped, point of V or U directed posterad. Ventral apotome (Fig.
24) yellow, rectangular, much wider than long (width/length ratio values 3.14 - 8; x =4.48; n
= 37); lateral margins rounded, anterolateral extensions present. Pair of triangular sclerites
posterad of caudal margin of ventral apotome.

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642

Smith and Lehmkuhl

Thorax similar to O. disjuncta (Fig. 32). Pronotum with light yellow transverse band
anteriorly, darker transverse band in middle, posterior portion white, marked by few light
brown spots. Each mesontal sclerite dark yellow anteriorly, white posteriorly, single seta near
anteromesal corner, as many as 19 setae on anterior and lateral portions of sclerite, three setae
on middle of sclerite. Metanotum with sa2 and sa3 each of single seta. Structure of trochantin
of propleuron as in O. disjuncta , as many as seven setae on dorsal surface. One to three setae on
mesoepisternum; one seta on mesoepimeron. As many as seven setae on metaepisternum; one
seta on metaepimeron. Foreleg (Fig. 35) without secondary setae on ventral surface of basal
part of trochanter; anterior surface of apical part of trochanter with two stout spine-like setae
on ventral surface, two setae near distal oblique margin of trochanter; setae on dorsal surface of
femur shorter relative to femur width than in O. disjuncta ; tibia with single spine-like seta on
distal portion of anterior surface; claw about as long as tarsus. Midleg with few spine-like setae
and finer setae on ventral surface of femur; most setae on dorsal surfaces of femur and tibia
shorter than in O. disjuncta ; claw shorter than tarsus, basal seta well developed. Hindleg (Fig.
36) with most setae on dorsal surfaces of femur and tibia shorter than in O. disjuncta ; tibia and
tarsus each with spine-like setae on ventral surface; claw shorter than tarsus, basal seta well
developed. Mesosternum without setae, metasternum with pair of setae.

Abdomen with anterior gills on segments II to VI or VII dorsally and ventrally; one pair of
pleural gills on segement II; in few specimens, gill on dorsal surface of lateral lobe of segment I.
Two groups of hooked spines at tip of median dorsal lobe of segment I as in O. disjuncta.
Segment IX with seta on each side of tergum near lateral margin, posterior margin of tergum
with six large and four small setae. Hairs and spines sparse on surface of caudal end of
abdomen. Claw of anal proleg with two dorsal denticles.

Mature larvae 6.5 - 9 mm in length.

Pupa. - Anterior surface of head with two pairs of setae subequal (Fig. 39). Abdomen with
anterior hook-bearing plates on terga of segments III to VII (Fig. 42) yellow to light brown;
anterior portion of each plate triangular, anterior end of triangle in most specimens directed
laterad of midline of posterior portion of plate. Lateral bars on terga of segments II to VIII
(Fig. 44) in most specimens not as wide as in 0, disjuncta. Other features of 0. avara pupa
similar to those already described for pupa of 0. disjuncta.

Male pupae 6-9 mm in length, female pupae 6-7 mm.

Larval and pupal cases. - The larval case of 0. avara is similar to that of 0. disjuncta.
Some pupal cases of 0. avara (Fig. 49) have some sand grains attached around the rim of the
anterior end of the case but the case lacks the prominent flange at the anterior end
characteristic of those of 0. disjuncta.

Bionomics. - Larvae of 0. avara inhabit turbid waters of the Saskatchewan River system as
well as clear, fast-flowing streams in the boreal forest region of Saskatchewan. In
Saskatchewan, adults of 0. avara were collected from June 16 to August 12. In cooler boreal
streams, pupae of 0. avara were collected from May 29 to July 15. This species is univoltine in
these streams. In the warmer waters of the Saskatchewan River system 0. avara pupae were
collected in mid-summer and in fall, which suggests that this species is bivoltine in these
warmer waters. The larva is the overwintering stage in this species.

Distribution. - O. avara is recorded throughout North America, from southern Canada to
Mexico (Ross, 1944). However, all previously published records are suspect since specimens of
O. disjuncta may have been incorrectly identified as O. avara in previous publications. In this
study we examined specimens of O. avara from Saskatchewan and Ontario in Canada, and

Two problematic North American caddisfly species

643

from Idaho and Montana in the United States.

In Saskatchewan O. avara larvae live in the main branches of the Saskatchewan River
system and are also common in streams in the boreal forests of the central region of the
province (Fig. 50) but they are absent from northern Saskatchewan.

Material examined. - SASKATCHEWAN South Saskatchewan R., 1/4 mi. upstream from the Queen Elizabeth
Power Station, 11. VI. 1972, 1 2 pupa-10.VH.1972, 8 3-12.V1I.1971, 1 3-13.VII.1971, 1 3, 2 2 -15.VII.1972 4 3,12
-19. VII. 1971, 2 3 -23. VII. 1972, 1 3 -15. VII. 1971 1 3 ;South Saskatchewan R., ferry e. of Hague, 21. VI. 1972, 1 3
-4.VII.1972, 4 3 ; South Saskatchewan R„ ferry no. of Birch Hills, 26.V.1972, 7 larvae-25.V.1973, 10 larvae-7.V1.1972, 2
3 pupae, 2 2 pupae, 2 larvae-12.VI.1972, 1 2 pupa, 13 3 -24. IV. 1973, 4 larvae-6.VII.1972, 2 3,12 -21. IX. 1972, 1
larva-20.VI.1973, 12 larvae-18.VII.1972, 1 2 -17. VIII. 1971, 6 larvae-8.V.1973 1 larva; South Saskatchewan R„ ferry n.
of Lemsford, 14. VII. 1971, 3 3 pupae, 2 2 pupae-12. VII. 1972, 2 2 , 2 3 , 3 3 pupae, 3 2 pupae-24.VII. 1972, 2 3 pupae, 3 2
pupae, 1 larva-6.IX.1972, 1 2 pupa-27.IX.1972, 1 larva-25.VI.1972, 1 larva; North Saskatchewan R., ferry 10 mi. e. of
Prince Albert, 14.IX.1972, 2 larvae-17.V.1972, 1 larva-1 5.VI. 1972, 13 3,5 2 -21. IX. 1972, 1 larva-15.VI, 1972, 1 2 ;
North Saskatchewan R. at Hwy. 3, 23. VI. 1972, 9 3,7 2; North Saskatchwan R. at Hwy. 5, 23. VIII. 1972, 10 larvae;
North Saskatchewan R., Prince Albert, 20.VI.1973, 1 3 pupa; Montreal R. at Hwy. 2, s. of La Ronge, 27.VI.1972, 7 3,3 2
, 1 larva-11. VI. 1976, 6 3,5 2 -16. VI. 1971, 6 3 -19.VI.1976, 1 3 ; Montreal R„ 28.V.1969, 1 Iarva-20.V1I.1960, 1 3
-15.VII.1960, 1 larva-28. VII. 1960, 5 larvae-22.VI.1960, 5 larvae-1 1. VIII. 1960, 16 larvae; Montreal R. at outflow of
Bigstone Lake, 4. V. 1977, 2 larvae-10.VI.1976, 3 larvae-6.VII. 1977, 1 larva, 4 pupae; Nipekamew R. at Hwy. 165,
16.VII.1975, 1 3,1 2 -13.VII.1976, 2 3 , 3 3 pupae, 1 2 pupa, 5 larvae; Weyakwin R. at Hwy. 2, 28.VI.1976, 11 3
-1 1. VI. 1976, 2 larvae, 4 pupae-16.VI.1976, 1 3 -4.VII.1975, 1 larva-1 1.VII.1976, 1 3 pupa, 1 2 pupa-1 4. VI 1. 1974, 12,1
3 -16.VII.1975, 3 3,2 2; Caribou Cr. at Hwy. 120, 29.V.1977, 3 3 pupae, 17 larvae-17.Vl.1977, 1 2 pupa, 2
larvae-1 2.IV. 1976, 3 larvae-1 6.VI 1.1 977, 13,12 -23.VI.1977, 9 3 , 12 2 , 3 larvae-17.VI.1976, 3 3,2 2,5
larvae-27.VI.1977, 1 3 pupa-13.VIl.1977, 28 3 , 16 2 , 1 3 pupa-1 5. VI 1. 1 976, 1 3 pupa, 1 2 pupa, 35 3 , 28 2 , 5
larvae-7. VII. 1977, 1 larva, 2 3 pupae, 1 2 pupa-23. V 1. 1 977, 1 3 pupa, 13,22 -6. VIII. 1976, 43,9 larvae-27.VI.1977, 1
prepupa-15. VII. 1976, 3 prepupae-17.VII.1976, 1 larva; Crean R. at Hwy. 2, 9. VI. 1976, 1 3 pupa; Torch R. at Hwy. 106,
26.IV.1977, 1 larva-16.VI.1976, 2 3 -2.VII.1975, 1 3 -15.VII.1976, 1 3 , 2 2 -5.VIII.1976, 4 3 , 2 larvae-21 .IX.1976, 8
larvae; Mistohay Cr. at Hwy. 224, 10.VII.1976, 38 3 , 15 2 , 1 larva- 1 1. VI 1.1 976, 1 3 pupa— 1 2. V 1 1 1. 1 975, 1 3 ; Broad Cr.
at Hwy. 104 2. VII. 1975, 1 3,1 2; Overflow R. at Hwy. 109, 1 1. VI. 1975, 2 larvae Overflow R., 1958, 1 larva; Taggart Cr.
at road to Dore L., 26.VI.1976, 1 2 pupa; ONTARIO -Streetsville, Credit River, Peel Co., 23.VII.1952, 4 3 , 34 2 (ROM):
MONTANA- Yellow Bay, Flathead L., 26.V1I.1965, 1 3 ; Missoula Co., Owl Cr., Stn. #4, between Placid L. and
Clearwater R., 9.VIII.1973, 13 3,41 2 (ROM); IDAHO- 20 mi. s. of Mack’s Inn, Fremont Co., 10. VII. 1969, 37 3 , 3 2
(ROM).

DISCUSSION

The taxonomic status of O. disjuncta has been misunderstood for more than 30 years, for
several reasons. First, the description and drawing of the male genitalia of O. disjuncta
provided by Banks (1920) were inadequate to permit specimens of O. disjuncta to be
distinguished from specimens of O. avara. Second, specimens of the two species are extremely
similar morphologically and, even if one can compare type specimens, without a large collection
of males of both species to compare with the types it would be difficult to determine the proper
taxonomic status of O. disjuncta. Third, since Ross (1944) and Denning (1956) suggested that
O. disjuncta was likely conspecific with O. avara , taxonomists have not concerned themselves
with clarifying this problem. Specimens of O. disjuncta were probably regarded as variants of
O. avara.

Preliminary evidence suggests that specimens of O. disjuncta have previously been identified
as O. avara. As indicated here, both species are widely distributed in North America, and it
seems likely that they are abundant not only in Saskatchewan but, also in many other regions of
North America. However, while published records for O. avara are numerous, none exist for O.
disjuncta , except for the type localities. Specimens of O. disjuncta have probably been collected
but, since they are not published under this or any other name, these specimens must have been
identified as O. avara. Our study of specimens of O. avara from the ROM support this

Quaest. Ent., 1980, 16(3,4)

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644

Smith and Lehmkuhl

conclusion. Of 1 1 vials labelled O. avara, lent by the ROM, eight contained specimens of O.
disjuncta. If misidentifications of specimens of O. disjuncta have, indeed, occurred, then some
of the published records for O. avara are probably incorrect.

Among specimens of the O. avara complex which we studied, two species are recognizable:
O. avara and O. disjuncta. However, study of the O. avara complex is not complete because we
examined specimens from only a limited number of North American localities. Taxonomists
should continue careful study of specimens collected at other localities, to determine if
additional species are attributable to this complex, or if the morphological differences between
O. avara and O. disjuncta are as clear at these localities as is reported in our study.

DISPOSITION OF MATERIAL

Some adult, larval and pupal specimens of the two Oecetis species examined in this study
will be deposited in the Royal Ontario Museum, Toronto, and in the Canadian National
Collection, Ottawa. The remainder are in the authors collections, or in the collection of the
Entomology Museum, Biology Department, University of Saskatchewan, Saskatoon,
Saskatchewan.

ACKNOWLEDGEMENTS

This study was supported by a National Research Council of Canada grant held by Dr.
D.M. Lehmkuhl. The senior author thanks the Institute for Northern Studies for the
scholarship which enabled him to study Saskatchewan caddisflies.

We thank Dr. G.B. Wiggins of the Royal Ontario Museum, Toronto, for loaning specimens
of Oecetis avara and Oecetis disjuncta , acknowledge his assistance in examining specimens,
and thank him for his many helpful comments concerning the taxonomic problem dealt with in
this paper.

Thanks go also to Dr. Alfred Newton of the Museum of Comparative Zoology for loan of
type specimens of O. avara and O. disjuncta.

We gratefully acknowledge the assistance of Mr. David Wong in preparation of the
photographs.

REFERENCES

Banks, N. 1895. New neuropteroid insects. Transactions of the American Entomological
Society 22:313-316.

Banks, N. 1899. Descriptions of New North American neuropteroid insects. Transactions of
the American Entomological Society 25: 199-218.

Banks, N. 1920. New neuropteroid insects. Bulletin of the Harvard University Museum of
Comparative Zoology 64: 297-362.

Denning, D.G. 1956. Trichoptera, pp. 237-270. In: Usinger, R.L. (Editor), Aquatic Insects of
California. University of California Press, Berkeley and Los Angeles.

Denning, D.G. and J. Sykora. 1966. New North American Trichoptera. Canadian

Two problematic North American caddisfly species

645

Entomologist 98: 1219-1226.

Ross, H.H. 1938. Lectotypes of North American caddisflies in the Museum of Comparative
Zoology. Psyche 45: 1-61.

Ross, H.H. The caddisflies, or Trichoptera, of Illinois. Illinois Natural History Survey Bulletin
23: 1-326.

Quaest. Ent., 1980, 16(3,4)

Fig. 1. O. disjuncta male genitalia, lateral aspect; Fig. 2. O. disjuncta aedeagus, lateral aspect; Fig. 3. O. avara male
genitalia, lateral aspect, showing cercus (c), and clasper (cl); Fig. 4. O. avara aedeagus, lateral aspect; Fig. 5. O. disjuncta
aedeagus, caudal aspect; Fig. 6. O. avara aedeagus, caudal aspect; Fig. 7. O. disjuncta enlarged view of aedeagus, caudal
(dorsal) aspect, showing internal structure; Fig. 8. O. avara enlarged view of aedeagus, caudal aspect, showing sclerotized
plate (sp) and internal sclerotized ring (ir); Fig. 9. O. disjuncta mesal process of segment X, dorsal aspect; Fig. 10. O.
disjuncta mesal process of segment X, dorsal aspect; Fig. 11.0. avara segment X, dorsal aspect, showing lateral lobe ( 1 b)
and mesal process (mp).

Two problematic North American caddisfly species

647

Fig. 12. O. disjuncta male genitalia, ventral aspect, showing membranous region (m) of sternum IX, and clasper (cl);
Fig. 13. O. avara male genitalia, ventral aspect, showing membranous region (m) of sternum IX, and clasper (cl); Fig.
14. O. disjuncta female genitalia, ventral aspect.

Quaest. Ent., 1980, 16(3,4)

648

Smith and Lehmkuhl

Fig. 15. O. avara, female genitalia, ventral aspect, showing ventrocaudal lobe (vl) of lateral sclerite of segment IX; Fig.
16. O. disjuncta female genitalia, lateral aspect, showing lateral sclerite (Is), cercus (c), and clasper (cl); Fig. 17. O.
avara female genitalia, lateral aspect, showing ventrocaudal lobe (vl) of lateral sclerite of segment IX.

Two problematic North American caddisfly species

649

Fig. 18. O. disjuncta larval head, dorsal aspect, showing frontoclypeal apotome (f), and parietal sclerite (p); Fig. 19. O.
avara larval head, dorsal aspect; Fig. 20. O. avara view of region in vicinity of anterolateral corner of frontoclypeal
apotome; Fig. 21. O. disjuncta larval head, lateral aspect; Fig. 22. O. avara larval head, lateral aspect, showing
subocular line (so).

Quaest. Ent., 1980, 16(3,4)

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Smith and Lehmkuhl

Fig. 23. O. disjuncta larval head, ventral aspect, showing ventral apotome (a), and triangular sclerite (t); Fig. 24. O.
avara ventral apotome, showing width (w), and length (lg) of apotome; Fig. 25. O. disjuncta ventral surface of preoral
cavity, showing plate (p) on dorsal surface of submentum, and tip of labrum (It); Fig. 26. O. disjuncta larval mandible,
dorsal aspect; Fig. 27. O. avara larval mandible, dorsal aspect; Fig. 28. O. avara labrum, dorsal aspect, showing lateral
setae (Is), anterior seta (s), and comb of spines (c), all on ventral surface of labrum; Fig. 29. O. disjuncta , one spine
from comb of spines on ventral surface of labrum; Fig. 30. O. disjuncta trochantin, lateral aspect; Fig. 31.0. disjuncta
caudal end of abdomen, dorsal aspect.

Two problematic North American caddisfly species

651

Figure 32. Oecetis disjuncta (Banks) thorax and first abdominal segment, dorsal aspect, showing group of hooked spines
(h).

Quaest. Ent., 1980, 16(3,4)

652

Smith and Lehmkuhl

Fig. 33. O. disjuncta trochanter and femur of foreleg, anterior aspect; Fig. 34. O. disjuncta hindleg, anterior aspect;
Fig. 35. O. avara foreleg, anterior aspect; Fig. 36. O. gvara hindleg, anterior aspect.

Two problematic North American caddisfly species

653

Fig. 37. O. disjuncta mandibles, dorsal aspect; Fig. 38. O. disjuncta head, anterodorsal aspect, showing antenna (a),
and ventral pair of setae (vs); Fig. 39. O. avara head, anterodorsal aspect; Fig. 40. O. disjuncta labrum, dorsal aspect;
Fig. 41. O. disjuncta hook-bearing plates on abdominal terga, showing anterior (ap), and posterior parts (pp) of plate;
Fig. 42. O. avara hook-bearing plates on abdominal terga; Fig. 43. O. disjuncta abdominal tergum, showing lateral
tergal bar (lb); Fig. 44. O. avara abdominal tergum; Fig. 45. O. disjuncta anal rod.

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Smith and Lehmkuhl

Fig. 46. O. disjuncta immature larval case, ventral aspect; Fig. 47. O. disjuncta mature larval case, ventral aspect; Fig.
48. O. disjuncta pupal case, showing flange (fl); Fig. 49. O. avara pupal case.

Two problematic North American caddisfly species

655

Fig. 50. Distribution of Oecetis disjuncta (Banks) and Oecetis avara (Banks) in Saskatchewan.

Quaest. Ent., 1980, 16(3,4)

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Smith and Lehmkuhl

THE EFFECT OF HYDROELECTRIC DAMS AND SEWAGE ON THE DISTRIBUTION
OF STONEFLIES (PLECOPTERA) ALONG THE BOW RIVER

D.B. Donald

Canadian Wildlife Service
1000, 9942-108 Street
Edmonton, Alberta
T5K 2J5

Quaestiones Entomologicae
16:665-670 1980

R.A. Mutch
Department of Biology
University of Calgary
Calgary, Alberta
T2N 1N4

ABSTRACT

Adult stoneflies (Plecoptera) were collected from 17 sites along 346 km of the Bow River.
Of 59 species collected in the study area, 43 were relatively common. Although a few species
were found throughout most of the study area, many had relatively narrow distribution limits.
An ordination technique differentiated four species associations. One of these associations was
in the subalpine and montane vegetation zones, one near the boreal zone, and two were in the
grassland zone. Sewage effluent from small towns had little or no effect on distribution of
stonefly species, but hydroelectric dams and sewage effluents from a large city reduced the
species diversity and abundance of Plecoptera. Two species were apparently eliminated from
over 150 km of river by dams and by sewage from the city of Calgary, while the distribution of
some species was not reduced appreciably by these factors.

Des “ mouches de pierres” adultes ( Plecoptera ) ont ete collectionnees dans 17 localites reparties sur 346 km le long de
la riviere Bow. Parmis 59 especes collectionnees au cours de cette etude, 43 etaient relativement communes. Si quelques
especes furent trouvees dans la plus grande partie de la region etudiee, de nombreuses especes presentent une distribution
reduite. Quatre associations ont ete identifies a Vaide d’une technique d’ordination. Line de ces associations existaient
dans la zone subalpine et dans la zone a vegetation montagneuse, une autre fut identifiee dans la zone boreale, et les deux
autres dans la zone des prairies. Les effluents d’egouts des petites villes ont peu ou n’ont pas d’effet sur la distribution
des especes de Plecopteres; par contre les barrages hydroelectriques ainsi que les effluents d’egouts des grandes citees
influencent sensiblement la diversite et l’ abondance des especes. Les barrages et les eaux d’egouts de la ville de Calgary
ont apparemment elimine deux especes sur 150 km le long de la riviere; ces facteurs ne semblent pourtant pas reduire de
maniere evidente la distribution de certaines autres especes.

TABLE OF CONTENTS

Introduction 658

Methods 659

The Study Area 659

Results 660

Discussion 662

658

Donald & Mutch

Acknowledgements 667

References 668

INTRODUCTION

Sequential changes in distribution of Plecoptera as well as other aquatic insects along rivers
has been documented in Europe (Berthelemy 1966, Kamler 1967) and in North America
(Dodds and Hisaw 1925, Donald and Anderson 1977, Knight and Gaufin 1966). The principal
objective of this present study was to describe distribution and associations of Plecoptera along
the Bow River, and to identify distributions that have been altered by human activity in the
watershed. This river is controlled by four hydroelectric dams, and several small towns and a
major city discharge sewage into the river.

For many North American aquatic insects, including Plecoptera, identification of immature
stages cannot be made below generic level (Wiggins 1966, Hynes 1970, Cummins 1974).
Because most adult stoneflies do not disperse far from the shoreline of rivers, we used
quantitative collections of adult stoneflies to give an estimate of abundance and distribution of
aquatic stages.

Figure 1 . Map of study area showing the location of seventeen collecting sites on the Bow River.

Stoneflies (Plecoptera) along Bow River

659

METHODS

At the beginning and middle of each month, adult stoneflies were collected for 30 minutes
along approximately 0.5 km of shoreline at each of 17 sites on the Bow River (Fig. 1).
Collections were made in 1976 and 1977 from March to October. At one station, located within
the city limits of Calgary, stoneflies were collected on a weekly basis, although only data
compiled from the bimonthly samples were used in the main part of this paper. At each site
vegetation was swept with an insect net, rocks along the shoreline were overturned and
examined, and overhanging banks and bases of trees were checked for stoneflies. Because
comparable sampling efforts were made at each site, these collections were presumed to be
semi-quantitative relative to other sites. All specimens collected were preserved in the field in
70% ethanol. Identifications were made primarily with the aid of keys by Gaufin et al., (1972).
Scientific nomenclature follows that of Baumann et al., (1977).

Mean specific conductance, and mean total coliform bacteria values were calculated from
unpublished data provided by Environmental Protection Service, Alberta Environment and by
Water Quality Branch, Environment Canada. Approximate locations of sites where
measurements of water quality were taken can be determined from Fig. 2. Number of samples
taken at each site ranged from 13 to 77 for specific conductance, and from 10 to 30 for total
coliform bacteria counts. Daily discharge readings were taken at six sites on the Bow River, and
at 12 sites on the larger tributaries of the Bow (Water Survey of Canada 1974). Number of
years for which daily measurements were taken at these gauging stations ranged from three to
65.

Stonefly associations at the 17 sites along the Bow River were analysed with the Bray-Curtis
polar ordination method (Whittaker 1973). The total number of each species collected at a site
was determined. These abundance values were then converted to a percent of the total number
of stoneflies collected at each site. The percent values were then used to determine similarity of
the fauna at each site with the fauna of the other 16 sites. The most dissimilar sites became
poles of the axes along which other sites are arranged.

THE STUDY AREA

The Bow River originates on the Continental Divide in Banff National Park and flows in a
south-easterly direction through much of southern Alberta. The extreme upstream site (site 1)
has a mean annual discharge of approximately 8.5 moc/s and is about 35 km from the
headwaters of the Bow River. The last site is 346 km downstream where mean annual discharge
is about 109 moc/s (Fig. 2). Over this 346 km distance the river passes through four vegetation
zones (Rowe 1972): subalpine, montane, boreal, and grassland. In general, mean annual
temperature increases downstream, while mean annual precipitation decreases. Maximum
summer water temperatures at the furthest upstream and downstream sites are about 13°C and
23 °C respectively. The Bow River is frozen over between December and March, but actual
time of freeze-up and break-up at a given site depends on elevation, year, gradient, and distance
from sewage outfalls or hydroelectirc dams.

Gradient of the Bow River in the study area is approximately 2.05 m/km and only few
relatively short stretches have a gradient noticeably different from this (Fig. 3). At each

Quaest. Ent., 1980, 16(3,4)

660

Donald & Mutch

282

KILOMETRES

Figure 2. The specific conductance, mean annual discharge, and total coliform bacteria for the Bow River. A decrease in
discharge shows location of weirs where water is taken for irrigation.

collecting site, areas of sand, gravel, and boulders were present.

The major dissolved constituents of the river water are bicarbonates of calcium and
magnesium. Concentrations of common anions and cations increase in the downstream
direction, similar to increase in specific conductance shown in Fig. 2. Oxygen concentrations
were near saturation throughout the study area. The lowest oxygen concentration, 7.5 mg/1,
was recorded downstream from Calgary.

Bow River water is used for town and city waterworks, generating electrical power, and
irrigation purposes. Along the river are four towns and one city (Fig. 1). Lake Louise and Banff
are resort towns, and their total population is usually much larger than number of permanent
residents indicated in Fig. 3. Sewage discharged into the Bow River from towns and the city
increases abundance of total coliform bacteria in the river (Fig. 2).

The four dams on the Bow River are used for generating electrical power (Fig. 3). The two
upstream dams and the one furthest downstream have relatively constant daily discharge
patterns, but the other dam has a variable daily discharge.

RESULTS

During this study, we collected a total of 4,372 specimens representing 59 species. Of these,
16 species were represented by a single specimen or were found at only one site. These 16
species were Oemopteryx fosketti (Ricker), Zapada frigida (Claassen), Paraleuctra forcipata
(Frison), Capnia gracilaria Claassen, Capnia petila Jewett, Alloperla serrata Needham and

Stoneflies (Plecoptera) along Bow River

661

Figure 3. The gradient, number of species, and abundance of Plecoptera at seventeen sites on the Bow River. Dark
triangles show location of hydroelectric dams. Vertical and horizontal bars show location and resident population of
towns and city (see Fig. 1). Dotted lines indicate areas where species diversity and stonefly abundance would reach zero
because of presence of reservoirs or sewage outfalls.

Claassen, Sweltsa borealis (Banks), Malenka flexura (Claassen), Perlomyia utahensis
Needham and Claassen, Isocapnia grandis (Banks), Isocapnia crinita (Needham and
Claassen), Capnia coloradensis Claassen, Megarcys subtruncata (Needham and Claassen),
Isoperla mormona Banks, Utaperla sopladora Ricker, and Calineuria calif ornica (Banks).

Distribution of 43 plecopteran species found along the Bow River is represented in Fig. 4.
There was considerable variation in altitudinal distribution. Some species were restricted to
either upstream or downstream sections, while a few species were found throughout much of
the study area (e.g. the chloroperlids Sweltsa coloradensis (Banks) and Alloperla severa
(Hagen).

Of 32 genera collected: 17 were represented by one species; 10 by two species; and five by
three or more species. In general, ranges of congeneric species overlapped considerably (e.g. the
perlodid species Cultus tostonus Ricker and Cultus aestivalis (Needham and Claassen) -
Fig. 4), but there were some striking exceptions. For example, there was significant spatial
separation between Triznaka species and between Isoperla species.

Quaest. Ent., 1980, 16(3,4)

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Donald & Mutch

Nemourids and leuctrids were restricted to upstream areas (sites 1-9), while the other
families of Plecoptera were represented throughout the study area (Fig. 4). Capniids were
absent or reduced in abundance below hydroelectric dams (sites 8-11), especially the central
dam (site 9 and 10, Fig. 4). Pteronarcids, capnids and perlids were absent or reduced in
numbers downstream from Calgary (sites 12-14).

Figure 3 shows the total number of species collected at each site. Number of species
decreased slightly downstream from both Banff and Canmore (sites 5 and 6). The fewest
species were collected at site 9, 4.1 km below the central hydroelectric dam, and immediately
downstream from Calgary (site 12). Approximately 30 km downstream from Calgary (site 15)
number of species increased to levels similar to upstream sites, but then decreased sharply in an
area that had no known environmental perturbations.

Stoneflies reached peak numbers downstream from Lake Louise (site 2), Banff (site 5), and
near the upstream city limits of Calgary (site 11) (Fig. 3). The smallest number of specimens
was collected below the central hydroelectric dam (site 9), and about 2 km below last sewage
outfall from Calgary (site 12).

An arrangement of the 17 collection sites in relation to two axes by Bray-Curtis ordination is
shown in Fig. 5. Four faunal associations were thus identified. Single associations occurred in
the montane and subalpine vegetation zone, and in the general area of the boreal zone; two
occurred in the grassland zone.

In order to obtain some information on reliability of our sampling method relative to number
of species present at a site, and relative to the aquatic populations of Plecoptera found at a site,
two comparisons were made. These are summarized below.

Fifteen plecopteran species were identified from site 11 where weekly samples were
collected. If the normal bimonthly program had been carried out only 13 species would have
been collected. The two species that were missed were represented by single specimens.
Therefore, by doubling the sampling effort, the number of species found at this site was
increased by 13%. Conversely, the bimonthly sampling program obtained about 87% of the
species, and missed only those species that were very rare.

At two sites, one upstream, the other downstream from the town of Lake Louise (site 1 and
2, Fig. 1), larval stoneflies were collected by taking three kick samples at each site 15 times
during 11 months of one year (Robinson and Smith Smith 1974). Identifications for this
benthic study were made to subfamily, genus, or to species in a few cases. Using subfamily as
the common level of identification, relative abundance of plecopteran larvae was compared to
relative, abundance of adults collected during the present study at these same sites (Table 1).
This table shows that our method substantially underestimated relative abundance of
Nemourinae, Isogeninae, and Acroneurinae at these stations, although our method obtained
significantly more Capniinae. A comparison of taxa identified from these two studies indicated
that the benthic study obtained 36% fewer taxa.

DISCUSSION

Comparison between adult and larval plecopteran collections from sites 1 and 2 on the Bow
River indicated the two sampling methods obtained the same subfamilies but in different
proportions (Table 1). Differences were probably related to vulnerability of species to either the

Stoneflies (Plecoptera) along Bow River

663

SUBALPINE | MONTANE | BOREAL | GRASSLAND

1 2 3 4 S 6 7 8 9 10 11 12 131415 16 17

Pteronarcidae

Pteronarcella badia
Pteronarcella regular is
Pteronarcys ealifornica
Taeniopterygidae

Taenionema paoificum
Doddsia occidentalis
Taeniopteryx nivalis
Nemouridae

Zapada cinetipes
Zapada Columbiana
Prostoia besametsa
Malenka ealifornica
Leuctridae

Paraleuctra occidentalis
Capniidae

Bolsheaapnia milami
Capnia cheama
Capnia confusa
Mesocapnia oenone
Capnia vernalis
Eucapnopsis brevicauda
Utacapnia trava
Vtacapnia Columbiana
Isocapnia vedderensis
Isooapnia integra
Perlodidae

Kogotus nonus
Isoperla petersoni
Isoperla longiseta
Isoperla fulva
Isoperla patricia
Megarays signata
Cultus aestivalis
Cultus tostonus
Isogenoides elongatus
Isogenoides colubrinus
Skuala parallela
Chloroperlidae
Sweltsa fidelis
Sweltsa coloradensis
Neaviperla forcipata
Triznakx diversa
Triznaka signata
Alloperla severa
Suwallia pallidula
Paraperla frontalis
Perlidae

Doroneuria theodora
Hesperoperla pacifica
Claassenia sabulosa

0 100 200 300

KILOMETRES DOWNSTREAM

Figure 4. Distribution of 43 species of Plecoptera from Bow River. Abundance of each species is indicated by thickness
of horizontal line. The thinnest line represents one to ten specimens collected, and thickest line represents 50 or more
specimens. Nomenclature follows Baumann (1977).

Quaest. Ent., 1980, 16(3,4)

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Donald & Mutch

TABLE I

PERCENT COMPOSITION BY SUBFAMILY OF BENTHIC1 AND AERIAL
PLECOPTERAN SAMPLES COLLECTED AT TWO SITES ON THE BOW

RIVER

Site 1 Site 2

Number of

samples

Subfamily

Benthos

15

Aerial

11

Benthos

15

Aerial

11

Nemourinae

16

6

18

4

Brachypterinae

+

1

6

4

Capniinae

11

31

6

26

Leuctrinae

-

2

-

1

Pteronarcinae

-

-

2

2

Isoperlinae

-

2

1

2

Perlodinae

6

1

25

3

Acroneuriinae

26-

3

5

2

Chloroperlinae

41

54

37

58

Paraperlinae

-

-

+

100

100

100

100

Total number / m2

289

1397

Total number

collected

140

303

1 Data compiled from Robinson and Smith (1974)

+ present; - not collected

benthic or aerial sampling method. Only rare species were added to the list of adult taxa found
at site 1 1 when the collecting effort was doubled at this site. These data suggest that bimonthly
collections of adult stoneflies approximate the relative abundance of aquatic and aerial stages
at any given site. Adult collections are more suitable than larval collections for determining
distribution of stoneflies because all specimens can be identified to species.

Bray-Curtis ordination identified four plecopteran associations from the study area (Fig. 5).
Upstream and downstream limits of some associations were near boundaries of vegetation zones

Stoneflies (Plecoptera) along Bow River

665

found in the same area. Climatic factors that determined distinct vegetation zones also
appeared to influence distribution of stonefly associations.

Plecopteran faunas in streams do not occur in discrete species groups. Typically, along the
length of a river there is a progressive change in species with a broad overlap in distribution of
many species (Knight and Gaufin, 1966, Donald and Anderson, 1977, and others). The
majority of species in the study area were found in two or more associations. Only 13 of 43
common species were limited in their distribution to one of the associations (Fig. 4). However,
Bray-Curtis ordination successfully identified those sites most similar to each other, and
therefore ordination can be used to delineate parts of a stream that have a similar fauna or
association.

In the following paragraphs, effects of hydroelectric dams and sewage effluents on species in
the four associations (Fig. 5) are evaluated, beginning with the plecopteran fauna found in the
subalpine and montane vegetation zone.

In the subalpine-montane zones (sites 1-7), there were changes in number of species and
overall abundance of Plecoptera at certain sites (Fig. 4). Increase in abundance of Plecoptera
downstream from Lake Louise and Banff was probably related to at least two factors: increase
in discharge and width of Bow River at these sites (2 and 5), and to stream fertilization from
organic sewage. An increase in the standing crop of benthos is typical of mild organic pollution
(Hynes 1960). Sewage from the towns did not affect the overall distribution of plecopteran
species with the possible exceptions of Utacapnia columbiana (Claassen) and Kogotus nonus
(Needham and Claassen) (Fig. 4).

There was a major discontinuity in distribution of the stonefly fauna in the boreal vegetation
zone. Seventeen species had either upstream or downstream distribution limits in or near this
vegetation zone. A similar situation occurred in the near pristine Waterton River drainage
where 58% of the common species had either upstream or downstream limits at 1235 m ( ± 100
m), the lower boundary of the montane zone (Donald and Anderson, 1977). These data suggest
that discontinuity in species distribution near the downstream limit of the montane belt on the
Bow River was due to natural changes in the lotic environment, and was not necessarily due to
effects of sewage and hydroelectric dams in this area.

In the boreal zone there was a sharp drop in both diversity and abundance of stonefly species
below the central hydroelectric dam (site 9, Fig. 3), followed by a gradual increase. It is well
known that for the first few kilometres below large dams species diversity and overall
abundance of stonefly larvae are reduced (Gore 1977, Radford and Hartland-Rowe 1971,
Spence and Hynes 1971, Trotsky and Gregory 1974, Ward 1976). Data presented by
Gore(1977) for a Montana river and by Ward (1976) for a Colorado river suggest that
complete recovery of a plecopteran fauna occurs about 30-60 km below dams, although this
recovery probably depends on many factors such as size of tributary streams, size of reservoir,
daily variation in water release, and release of either epilimnetic or hypolimnetic water.

As indicated by reduced species diversity and abundance, site 9 was unfavourable for
plecopterans. This site was 4.1 km below the hydroelectric dam with the greatest daily variation
in discharge. Three other sites (8, 10 and 11) were located between 14.2 and 20.6 km below
dams (Fig. 3). Dams have an unfavourable effect on plecopterans, and because three of the four
dams in the study area were located in the boreal zone, it is possible that they were an
important factor determining plecopteran faunal association identified from this section of the
Bow River (sites 8-10, Fig. 5).

Quaest. Ent., 1980, 16(3,4)

666

Donald & Mutch

Figure 5. Scatter diagram of seventeen sites in the study area derived by Bray-Curtis polar ordination. Figure shows
presence of four plecopteran faunal associations in the study area.

In other rivers in western North America, larvae of Capnia vernalis Newport and
Isogenoides coluhrinus (Hagen), (Gore 1977), Pteronarcys calif ornica Newport (Elder and
Gaufin 1973 and Ward \916),Skwala parallela (Frison), Claassenia sabulosa (Banks),
Pteronarcella badia (Hagen), and Triznaka signata (Banks) (Ward 1976) are absent from, or
reduced in numbers below dams. Similar results were found for adults of these same species
along the Bow River (Fig. 4).

In the grassland vegetation zone reduction in the plecopteran fauna occurred immediately
downstream from Calgary (site 12). This part of the river received organic wastes as well as
some thermal and toxic pollutants from Calgary. Deterioration in water quality in this area was
indicated by a large increase in abundance of total coliform bacteria (Fig. 2). Many capniids,
perlids, and pteronarcids were either reduced in abundance or were absent from this zone.
Species completely eliminated from at least 26 km of river downstream from Calgary (sites

Stoneflies (Plecoptera) along Bow River

667

12-14) were Pteronarcys calif ornica Newport, Capnia confusa Claassen, Eucapnopsis
brevicauda (Claassen), Utacapnia trava (Nebeker and Gaufin), Utacapnia columbiana
(Claassen), Isocapnia integra Hanson, and Hesperoperla pacifica (Banks). Four other species
[Skwala parallela (Frison), Isoperla patricia Frison, Suwallia pallidula (Banks), Triznaka
signata (Banks)] appeared to be tolerant of some organic pollution as indicated by their
abundance two kilometres downstream from Calgary.

In general, stoneflies are intolerant of severe organic pollution and are usually eliminated by
it (Gaufin 1958, Gaufin 1962, Gaufin 1973, Hynes 1960, Paterson and Nursall 1975).
Stoneflies probably did not occur immediately below the city sewage outfalls. The relatively
high stream gradient and high levels of dissolved oxygen in the Bow River contributed to a
rapid recovery of water quality that permitted a few species to exist two kilometres downstream
from Calgary.

Downstream from the last sewage outfall from sites 12 to 15 there was a progressive
increase in the species diversity and abundance of Plecoptera (Fig. 3). This part of the Bow
River was in a recovery zone where many species that were intolerant of the upstream effects of
severe pollution once again reappear. Although the distributions of some species have not been
greatly reduced (e.g. the perlid Hesperoperla pacifica ), at least two capniid species ( Utacapnia
columbiana and Isocapnia integra have probably been eliminated by dams and sewage from
more than 150 km of river (Fig. 4).

The sharp drop in species diversity, but not in abundance of stoneflies, at sites 16 and 17 in
the grassland belt was probably due to natural conditions in the lotic environment that were
unfavourable for some species of Plecoptera. Reduced gradient (Fig. 3) and high summer
temperatures could be responsible. In the Waterton River drainage, distributions of Capnia
confusa , Eucapnopsis brevicauda , Taenionema pacificum (Banks), and Hesperoperla
pacifica did not extend far into the grassland zone (Donald and Anderson, 1977). These four
species had a similar distribution in the Bow River. At least six other species represented at site
15, but not at Sites 16 and 17, have not been collected from rivers in south-central Alberta
(Ricker 1943 and unpublished distribution records). These data suggest that change in the
plecopteran fauna at sites 16 and 17 was due to natural changes in the lotic environment. The
species represented at these two sites were identified as a second grassland association of
Plecoptera (Fig. 5).

In this study, collections of adult Plecoptera were used to document patterns in distribution
of stonefly species in the Bow River. Distribution of these species was influenced by
hydroelectric dams, domestic and industrial sewage and by natural environmental factors
(probably climate, river gradient, etc.). It follows, that in regions with a diversity of plecopteran
species, the distribution patterns of adult Plecoptera can be used as an indicator of effects of
severe organic pollution and hydroelectric dams on the lotic environment.

ACKNOWLEDGEMENTS

We are grateful for the suggestions and criticisms of R.S. Anderson during the preparation
of the manuscript. W.E. Ricker confirmed the identification of several species of Plecoptera
collected from the Bow River.

Quaest. Ent., 1980, 16(3,4)

668

Donald & Mutch

REFERENCES

Berthelemy, C. 1966. Recherches ecologiques et biogeographiques sur les plecopteres et
coleopteres d’eau courante (Hydraena et Elminthidae) des Pyrenees. Annales de
Limnologie 2:227-458.

Baumann, R.W., A.R. Gaufin, and R.F. Surdick. 1977. The stoneflies (Plecoptera) of the
Rocky Mountains. Memoirs of the American Entomological Society (Philadelphia)
31:1-208.

Cummins, K.W. 1974. Structure and function of stream ecosystems. Bioscience 24:631-641.

Dodds, G.S., and F.L. Hisaw. 1925. Ecological studies on aquatic insects. IV. Altitudinal range
and zonation of mayflies, stoneflies, and caddisflies in the Colorado Rockies. Ecology
6:380-390.

Donald, D.B., and R.S. Anderson. 1977. Distribution of the stoneflies (Plecoptera) of the
Waterton River drainage, Alberta, Canada. Syesis 10:1 1 1-120.

Elder, J.A., and A.R. Gaufin. 1973. Notes on the occurrence and distribution of Pteronarcys
californica Newport (Plecoptera) within streams. Great Basin Naturalist 33:218-220.

Gaufin, A.R. 1958. The effects of pollution on a midwestern stream. Ohio Journal of Science
58:197-208.

Gaufin, A.R. 1962. Environmental requirements of Plecoptera. Biological Problems in Water
Pollution. Third Seminar. (Ed. by C.M. Tarzwell). United States Department of
Health, Education, and Welfare.

Gaufin, A.R. 1973. Use of aquatic invertebrates in the assessment of water quality. Biological
Methods for the Assessment of Water Quality. American Society for Testing and
Materials Special Technical Publication 528.

Gaufin, A.R., W.E. Ricker, M. Miner, P. Milam, and R.A. Hays. 1972. The stoneflies
(Plecoptera) of Montana. Transactions of the American Entomological Society
(Philadelphia) 98:1-161.

Gore, J.A. 1977. Reservoir manipulations and benthic macroinvertebrates in a prairie river.
Hydrobiologia 55:1 13-123.

Hynes, H.B.N. 1960. The Biology of Polluted Waters. University of Toronto Press. 202 pp.

Hynes, H.B.N. 1970. The ecology of stream insects. Annual Review of Entomology 15:25-42.

Kamler, E. 1967. Distribution of Plecoptera and Ephemeroptera in relation to altitude above
mean sea level and current speed in mountain waters. Polskie Archwum Hydrobiologii
14:29-42.

Knight, A.W., and A.R. Gaufin. 1966. Altitudinal distribution of stoneflies (Plecoptera) in the
Rocky Mountain drainage system. Journal of Kansas Entomological Society
39:668-675.

Paterson, C.G., and J.R. Nursall. 1975. The effects of domestic and industrial effluents on a
large turbulent river. Water Research 9:425-435.

Radford, D.S., and R. Hartland-Rowe. 1971. A preliminary investigation of bottom fauna and
invertebrate drift in an unregulated and a regulated stream in Alberta. Journal of
Applied Ecology 8:883-903.

Ricker, W.E. 1943. Some prairie stoneflies (Plecoptera). Transactions of the Royal Canadian
Institute 26:3-8.

Stoneflies (Plecoptera) along Bow River

669

Robinson, D.J. and R.E. Smith. 1974. Limnological study of the Bow-Pipestone River
watershed in the vicinity of Lake Louise, Banff National Park. Canadian Wildlife
Service Manuscript Report. 84 pp.

Rowe, J.S. 1972. Forest regions of Canada. Department of the Environment, Canadian
Forestry Service, Publication Number 1300:1-172.

Spence, J.A., and H.B.N. Hynes. 1971. Differences in benthos upstream and downstream of an
impoundment. Journal of Fisheries Research Board of Canada 28:35-43.

Trotsky, H.M., and R.W. Gregory. 1974. The effects of water flow manipulation below a
hydroelectric power dam on the bottom fauna of the Upper Kennebec River Maine.
Transactions of the American Fisheries Society 103:318-324.

Ward, J.V. 1976. Comparative limnology of differentially regulated sections of a Colorado
mountain river. Archiv fur Hydrobiologie 78:319-342.

Water Survey of Canada. 1974. Historic stream-flow summary: Alberta to 1973. Department
of the Environment, Inland Water Directorate, Publication Number En36-418/1973-3.
327 pp.

Whittaker, R.H. (ed.) 1973. Ordination and classification of communities. Junk, The Hague.
Wiggins, G.B. 1966. The critical problem of systematics in stream ecology. Organism -
Substrate Relationships in Streams. (Ed. by K.W. Cummins, C.A. Tyron Jr., and R.T.
Hartman). The Pymatuning Symposia in Ecology, Special Publication Number 4.
University of Pittsburgh.

Quaest. Ent., 1980, 16(3,4)

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Donald & Mutch

SAWFLIES (HYMENOPTERA: SYMPHYTA) FROM GEORGE LAKE, ALBERTA

David R. Smith1

Systematic Entomology Laboratory, IIBIII
Agricultural Research
Science and Education Administration
U.S. Dept of Agriculture

Washington, D.C.

Quaestiones Entomologicae
16:681-670 1980

ABSTRACT

•I Seventy-three species of Symphyta are recorded from George Lake, Alberta. Of this total,
66 species were collected by the author in a three day period in 1978, and seven species are
recorded from the University of Alberta insect collection. Most species are found in eastern
North America; only seven of the species recorded are known only from western Canada and
United States.

RESUME

Soixante-treize especes de Symphytes ont ete inventoriees a George Lake, en Alberta. De ce total, l’auteur en a
collectionne soixante-six au cours d’une excursion de trois jours en 1978. Les sept autres especes se trouvaient dans la
collection d’insectes de l’Universite de l’Alberta. La plupart des especes se trouvent aussi dans Test de PAmerique du Nord;
seulement sept des especes rapportees ici ne sont connues que de l’ouest du Canada et des Etats-Unis.

In 1978 I had the privilege of spending three days, June 1 to June 3, at the University of
Alberta s George Lake Field Station about 50 miles northwest of Edmonton, Alberta. The
area consists of about one square mile of forest bordered on one side by the lake and on the
other sides by farmland. During this time, I collected 66 species of Symphyta. An additional
seven species were found in the University of Alberta insect collection, bringing the total
recorded from George Lake to 73 species. This is not a complete list, but a good indication of
the number of species that can be found in a small area of mixed vegetation. A similar account
was given by Strickland (1954) who collected 53 species of sawflies during a period of two
weeks in an area of about a half square mile near Gull Lake, Alberta.

Most of the specimens were collected by sweeping or directly from the foliage along a forest
trail to the lake, on the roadside and in a small cleared area with low vegetation. The remainder
were collected by Malaise traps set up in the forest.

‘c/o U.S. National Museum, Washington, D.C. 20560

672

Smith

All specimens were identified by me except for the Pristiphora which were determined by
H.R. Wong. Those identified as “sp.” or “spp.” cannot be named until taxonomic difficulties in
those genera are resolved.

Only a few generalities can be given about affinities of the sawfly fauna of George Lake,
because this is not a complete survey and several species cannot be identified. Of the 55
identified to species, 47 are also found in eastern North America; of these 47, 17 are
transcontinental in Canada and northern United States, 17 are both transcontinental and
Holarctic, and 13 are primarily eastern, with Alberta on the western edge of their distributions.
Consequently, most of the species from George Lake are the same as those one would expect to
collect in southeastern Canada and northeastern and north central United States. Only one
species, Empria evansi , is so far known only from Alberta. The other seven species are mainly
western; these are Birka nordica (Alberta, Alaska, British Columbia, Yukon), Dolerus nasutus
(Alberta and Montana to British Columbia and California), Monardis pulla (Saskatchewan
and Colorado to British Columbia and Utah), Allantus albolabris (Alberta and Colorado to
Alaska and California), Macremphytus lovetti (Alberta and Montana to British Columbia and
Oregon), Tenthredo fraternalis (Alberta, British Columbia), and Tenthredo varipicta (Alaska
to Alberta and California). Thus there is a slight mixture of some western species, but most
species from George Lake are typical components of the eastern deciduous forests and
temperate and boreal transcontinental regions. When all the material is identified, I would
expect similar results.

In the following list (H) = Holarctic, those species or subspecies also found in parts of
Eurasia and all of which are transcontinental in North America, (T) = transcontinental
species or subspecies found only in North America, (E) = eastern species or subspecies for
which Alberta is the western edge of their range, and (W) = species which are mainly western
in distribution, mostly from the Rocky Mountains to the West Coast. An asterisk indicates a
record from the Strickland Museum, University of Alberta.

PAMPHILIIDAE

Pamphilius ochreipes (Cresson) (T)

CIMBICIDAE

Zaraea inflata Norton (E)

ARGIDAE

Arge clavicornis (Fabricius) complex (H)

Sawflies from George Lake, Alberta

673

TENTHREDINIDAE

Selandriinae

Birka nordica Smith (W)

Dolerinae

Dolerus aprilis (Norton) (E)

Dolerus elderi Kincaid (H)

Dolerus nasutus MacGillivray (W)

Dolerus neocollaris neocollaris MacGillivray (E)
Dolerus sericeus sericeus (Say) (T)

Dolerus similis similis (Norton) (T)

Dolerus subfasciatus neoaprilis MacGillivray (T)
Dolerus yukonensis yukonensis Norton (H)
Dolerus sp.

Loderus eversmanni acidus MacGillivray (T)
Loderus pratorum albifrons (Norton) (H)
Loderus vestigialis apricus (Norton) (H)

Heterarthrinae

Fenusa pusilla (Lepeletier) (H)

Blennocampinae

Monophadnoides geniculatus (Hartig) (H)
Monophadnoides pauper (Provancher) (E)
Monophadnoides sp. near conspiculatus MacGillivray (E)
Phymatocera sp.

Monardis pulla Smith (W)

Quaest. Ent., 1980, 16(3,4)

674

Smith

Allantinae

*Empria ignota (Norton) (T)

Empria improba (Cresson) (T)

Empria maculata (Norton) (T)

*Empria obscurata (Cresson) (T)

Empria evansi Smith (Alberta)
Ametastegia sp.

Monostegia inferentia (Norton) (E)
Phrontosoma broccum Smith (T)
Allantus albolabris (Rohwer) (W)
Allantus mellipes (Norton) (E)
*Macremphytus lovetti MacGillivray (W)
Taxonus pallicoxus (Provancher) (E)

Nematinae

Priophorus morio (Lepeletier) (H)

Priophorus pallipes (Lepeletier) (H)

Fallocampus americanus (Marlatt) (T)

*Hemichroa crocea (Geoffroy) (H)

Hemichroa militaris (Cresson) (T)

Pachynematus spp. (Two species that cannot be named
at present. One of the two species should be marked *).
Nematus oligospilus Foerster (H)

Nematus spp. (Three species that cannot be named
at present).

Pontania spp. (Three species that cannot be named
at present).

Phyllocolpa sp.

Euura sp.

Amauronematus spp. (Five species that cannot
be named at present).

Pristiphora borea (Konow) (H)

Pristiphora cincta Newman (H)

Pristiphora rufipes Lepeletier (H)

Pristiphora siskiyouensis Marlatt (T)

Pristiphora sycophant a Walsh (T)

Pristiphora zella Rohwer (E)

Tenthredininae

Rhogogaster californica (Norton) (H)

P achy protasis rapae (Linnaeus) (H)

Macrophya trisyllaba (Norton) (E)

Sawflies from George Lake, Alberta

675

Macrophya varia (Norton) (E)

* Tenthredo colon Klug (H)

Tenthredo concessa Norton (E)
*Tenthredo fraternalis (Ross) (W)
Tenthredo leucostoma Kirby (E)
Tenthredo piceocincta Norton (T)
*Tenthredo varipicta Norton (W)
Tenthredo sp. near pectoralis Norton (T)

Janus integer Norton (T)

CEPHIDAE

ACKNOWLEDGEMENTS

I thank George E. Ball and W. G. Evans, University of Alberta, Edmonton, for allowing use
of the University of Alberta Field Station at George Lake for my studies. My thanks are
extended also to H.R. Wong, Canadian Forestry Service, Northern Forest Research Centre,
Edmonton, Alberta for identifying the Pristiphora specimens.

REFERENCES

Strickland, E.H. 1954. A key to the females of Tenthredo of the Canadian Prairies
(Hymenoptera, Tenthredinidae). Canadian Entomologist 86: 278-281.

Quaest. Ent., 1980, 16(3,4)

676

BOOK REVIEWS

GRIFFITHS, G.C.D. (Editor). Flies of the Nearctic Region. E. Schweizerbart’sche
Verlagsbuchhandlung (Nagele u. Obermiller) Stuttgart, 1980.

The above gives editor, title, and publisher of a new series about classification and
identification of the dipterous fauna of the New World (including Greenland, but excluding
Iceland), from arctic North America south to the Isthmus of Tehuantepec excepting the
Mexican coastal lowlands, and including Bermuda but not the other islands of the West Indies.
This series was conceived and organized by the editor, Graham C. D. Griffiths, and is intended
to be a counterpart of the monumental Palaearctic series “Die Fliegen der palaarktischen
Region.” Like the latter work, “Flies of the Nearctic Region” will be multi-authored, and will
appear in numbered issues, organized in a hierarchy of Volume, Part, and Number. The
sequence of numbering is based on a reconstructed phylogeny of the Order Diptera, with
volume I to deal with general aspects. The taxonomic section is scheduled to appear in volumes
II to IX, and each issue will treat a particular supraspecific taxon and its members. Numbers
will be published in the sequence in which they are prepared, and subsquently can be grouped
for binding, as Parts and Volumes are completed.

The first two issues are dated 1980, and I will review them after a few general
comments.The paper covers are attractively rendered in two colors, with white and black print,
and with an illustration of the head of a muscoid fly, apparently the logo of the series. Also
included on the front cover is the logo of the publisher. The paper seems to be of good quality,
but it is not high gloss. This, plus a clear, simple style of type, with justified right edge and
generous margins, gives each page a pleasing appearance. Overall, one is left with the
impression that printing mattters are in the hands of master craftsmen. Indeed, one can agree
with a quotation from Thucydides that appears on page V, following the Foreword in Volume I:
“This is composed more as a possession for ever than as a prize piece for immediate listening”.

Volume I. Handbook. Part 1. History of Nearctic Dipterology, by A. Stone. XIII + 62 pp.

In the Foreword, the great master dipterist, Erwin Lindner gives a brief synopsis of his
efforts to organize “Die Fliegen der palaarktischen Region”, and extends his best wishes to
G. C. D. Griffiths in his plans to produce a counterpart for the Nearctic Region. This brief
salutation is folowed by a fine photograph of Dr. Lindner, with a statement dedicating the new
series to him, on his 91st birthday.

The Preface, by Dr. Griffiths, acknowledges Lindner’s work, and expresses the hope that the
Nearctic counterpart will be completed by the year 2000. A map indicates the southern limits
of the area covered, and a “List of Abbreviations for denoting locations of specimens”
concludes the preface. I think it would have been desirable to include here the “Outline of
proposed volume structure” that was published in an advertisement for the series.

In 60 pages, Alan Stone provides a remarkable array of historical data, focussed on study of
the Nearctic fauna. In a section treating publications, he describes contributions by various
authors to morphological, systematic, physiological, genetic, and economic aspects of flies. The
“History of the Families” is a thumbnail sketch of progress made with study of each family,
including for each, number of valid (and invalid) genera and species. This treatment of
families, complete with bibliography, is followed by brief biographical sketches arranged

677

chronologically by date of birth, of 56 “leading dipterists”, from Fabricius (1745) to Saether
(1936). In this context, “leading dipterist” means one who has described 100 species or more
of Nearctic flies. Words are well chosen, and statements are succinct. Overall, the presentation
is descriptive rather than analytical or critical.

Dr. Stone suggests that these workers, though different from one another in many ways,
probably shared in common “a boyhood interest in nature”. Grouping them in quarters, he
points out that “the first fourth, chronologically, proposed names for Nearctic Diptera in an
average of 41 families;. ..the second fourth, 20 families;. ..the third fourth, 16 families; and the
last fourth, 6 families”. He identifies this as a trend to specialization that will probably
continue, and that although application of new techniques might radically change entomology,
“the enthusiastic naturalist turning a pinned specimen will long be needed”.

Although Dr. Stone’s treatment of historical aspects is rich and varied in detail, it lacks
elements of association, that, if considered, would have provided the sense of continuity that
history should convey. He acknowledges that “history ... includes the background and training
of the scientist”, but he does not draw attention to professor-student lineages. Perhaps none
exist among dipterists, but if not, even this deserves comment. Nor does he consider explicitly,
impacts of generalizing ideas on study of flies; for example, evolution, biological species
concept, sympatric speciation, phylogenetic systematics as expounded by another master
dipterist, Willi Hennig, vicariance biogeography, cytology, and so on. Be that as it may, the
information he provides can be used by future workers, and the histories they write will be
better because they will be able to build on the work of Alan Stone. Indeed, his contribution is a
worthy beginning for “Flies of the Nearctic Region”.

Volume V. Homeodactyla and Asilomorpha Part 13, Number 1. Bombyliidae, by J. C. Hall
and N. Z. Evenhuis, pp. 1-96.

Included in this issue is an introduction to the Nearctic Bombyliidae, with keys to
subfamilies and to the genera of Bombyliinae, and a taxonomic treatment of Bombylius and its
59 Nearctic species and subspecies. The key to these lower-ranking taxa follows the descriptive
section.

Treatments of species include: synomyny; discussion of type material; description of
structural features of adults; data about life history; and geographical distribution. The
succinct descriptions are supplemented by good line drawings of male genitalia and
spermathecae of females, and of wings of selected species. Illustrations are located near the
descriptions that they are intended to supplement, and thus spread through the text.

No attempt is made by the authors to seek patterns of relationship. In fact, the treatments
are arranged alphabetically by first letter of the specific epithets, so that one cannot infer
anything from the sequence. A range map is provided for only one species ( B . anthophoroides
Evenhuis). Otherwise, one must attempt to visualize distribution patterns from a list of states
from which each species has been recorded. Geographical variation is not mentioned, so the
descriptions take on a rather typological air. The authors explain in the introduction that these
and related topics will be considered at some future time. For the present, presumably, workers
must be satisfied with what seems to be a rather uninspiring treatment, of interest mainly to
specialists and to those who want to name their collections of bee flies.

I hope that future issues will provide treatments that have more general significance, but
that retain the excellent style of presentation of Hall and Evenhuis.

Each of these numbers is costly: $38.50 for Part 1, and $44.40 for V.13.1, in U. S. dollars.
But, recalling the introductory quotation from Thucydides and considering that one good meal

Quaest. Ent., 1980, 16(3,4)

678

with good wine and served in a good restaurant, for one person can cost $25.00 (and up!), the
issues of the “Flies of the Nearctic Region” are not unreasonably priced. Furthermore, their
value is likely to increase with the passage of time. Certainly, dipterists must have the series,
and entomological bibliophiles who wish to own fine publications will want it, too. For the rest
of us, it might be a toss-up between buying various issues or investing in some other worldly
pleasure. However, this series is worth having, and publisher, editor, and authors of the first
parts are to be congratulated for their efforts.

G. E.Ball

HOWDEN, H. F. and O. P. YOUNG. 1981. Panamanian Scarabaeinae:Taxonomy,
distribution and habits (Coleoptera, Scarabaeidae). Contributions of the American
Entomological Institute, 18 (1): 204 pp., 216 figures. (Separates available from the senior
author, for $15.00, U.S.).

According to the authors, this publication is a “review” rather than a “revision”, for the
taxa are described in terms of Panamanian material, only, and types of previously described
species were not studied in detail. The stated justification for publication at this time is to
provide a volume that will serve a need for identification of dung beetles by ecologists,
ethologists, and economic entomologists who are or who might become interested in way of life
of these animals. Scarabaeine adults exhibit complex behavior patterns in relation to use of
dung, and are therefore of interest to many biologists. The unstated justification for this
publication is the senior author’s intense interest in and enthusiasm for the heavily armored,
bumbling, horned monsters with disgusting alimentary habits, that are included in the
Scarabaeinae.

In the taxonomic part of the paper, 22 genera and their 113 species are keyed, diagnosed,
compared and described. Illustrations are included toward the end of the publication. Most are
SEM photographs. They are adequate rather than elegant.

This paper contains a useful gazetteer providing for each locality mentioned in the text
latitude and longitude, elevation (in meters), and relation to nearest major feature, so that a
particular place can be located by those who have at their disposal only rather general maps of
the area.

Figure 1 is an outline map of the Republic of Panama, with provinces labelled and their
boundaries indicated. Fig. 260 is a map showing elevations and Fig. 261 illustrates distribuion
of forest types of life zones in Panama. Thus, geographical aspects of this study are very well
portrayed.

In a few pages, the authors provide insights about behavior patterns of some species and
draw attention to aspects of behavior that require further investigation. These notes summarize
the wealth of information that the authors were able to gather in two man years of collecting
and observing in Panama. This field work has enlarged and enriched their knowledge of
tropical scarabaeines, and has given them insight that is denied to systematists who confine
their activities to study of preserved specimens housed in museum drawers.

Distribution patterns of the scarabaeine fauna of Panama are considered against a
background of topographical and geological changes during Tertiary time. The species are

679

arranged in two major zoogeographic groups: endemics (in Panama, or in Panama and Costa
Rica); and species that are more wide-ranging. In turn, species in the latter group are arranged
in three subgroups: widespread (in other parts of Central America, Panama, and South
America); those in Panama and South America, only; and those in Panama and Central
America, only. This last group, plus the Panamanian endemics, comprise the endemic Central
American fauna, which represents 52 per cent of the total. The authors correlate this high rate
of endemism in Central America with isolation, by seaways, of Central America from South
America, during much of the Tertiary period. They infer that, during the time of isolation,
differentiation took place. Further, they propose that species occurring now in both Central and
South America attained the present ranges when the seaways were closed as a result of
orogenies in Central America, leading to development of emergent land, and a terrestrial
connection of the two areas. This proposed sequence of events accounts nicely for the observed
patterns, and correlates well with inferences of various other recent authors, who have studied
distribution patterns of other taxa in Middle America.

A more detailed examination of the data shows that average body size is smaller for
members of Panamanian endemic species than it is for members of the wide-ranging groups.
From this, Howden and Young infer that smaller size may be correlated with flight behavior as
it relates to foraging, which in turn may relate to dispersal. Thus, the smaller species may be
inherently less vagile than are the larger ones. Hence, they have remained in their areas of
origin, that is, the areas that were above sea level during Tertiary times.

This is a reasonable explanation, but I wonder if more might be involved than dispersal
ability. The small endemics might represent older, less progressive stocks, and might have
remained in their areas of origin because they have been unable to compete successfully with
later-evolving, more progressive stocks comprised of species whose adults attain large size. To
test this hypothesis, a phylogenetic analysis of the scarabaeine fauna of Middle America is
required, and this the authors have not undertaken- nor do they recommend such an analysis.
In my view, this is an unfortunate oversight, for the missing system of hypotheses limits
markedly ability to interpret the zoogeographic data.

In spite of this one omission, the publication overall is fine, and contains information of
value to a wider range of biologists than those who wish to identify their Panamanian
scarabaeines. It should be on the shelves of coleopterists in particular, systematic entomologists
in general, ethologists, and biogeographers.

G.E. Ball

Reigert, P.W. 1980. From arsenic to DDT: A history of entomology in western Canada, xii
+ 357 pp. University of Toronto Press. Price:$30.00. ISBN 0-8020-5499-4.

Perhaps more than any other group of scientists, entomologists revel in writing histories of
themselves and their science. Although some of these (e.g. Mallis, “American Entomologists”;
Weiss, “The Pioneer Century of American Entomology”) briefly mention Canadian
entomology, Riegert’s book represents the first attempt to collect the history of entomology in
any part of Canada in one place. The book is organized into four parts encompassing 20

Quaest. Ent., 1980, 16(3,4)

680

chapters. “Early encounters”(Part I) describes problems encountered by early explorers(e.g.
Hearne, Palliser, Henry, Thompson), boundary surveyors and settlers with biting flies and
grasshoppers. This section is perhaps the most interesting in the entire book. Riegert makes
good use of quotes from various travellers that help in conveying a sense of the real suffering
endured by these people. The section concludes with a chapter about collectors and naturalists.
Part II(“The first professionals”) describes the beginnings of the federal and provincial
entomolgical services. It traces the efforts of such notables as Fletcher, Hewitt, Criddle and
Strickland in establishing pest monitoring and control programs. Part III (“Insects of British
Columbia”) follows the work of such people as Hearle, Downes, Glendenning, and Buckell in
controlling various crop pests, mosquitoes and grasshoppers. It concludes with a short chapter
about insect pests of Indian orchards. Part IV is entitled “Insects of the prairies” and deals in
great detail with outbreaks of wheat stem sawfly, various species of larvae and, above all,
grasshoppers. In fact, nearly 25% of this book is devoted to grasshopper outbreaks. Such figures
as King, Strickland, Criddle, and Seamans are prominent. Part V(Specialization) has chapters
dealing with livestock pests, stored products pests, entomology in universities and a summary
chapter. Parts II through V deal with pest control problems(except Chapter 19). They are
written in a clear, unambiguous, though rather mundane style that traces pest control incident
by incident. These sections are livened every now and then with anecdotes but these are few and
far between. There are several odd inclusions that seem to be afterthoughts. Chapter 17(Pests,
paralysis and plagues) ends with an account of Grylloblatta campodeiformis(see below), an
insect species that is not a pest and has nothing to do with paralysis or plagues. Chapter 16 is
entitled “Worms”. The choice of title is poor. The animals described are not worms(e.g.,
Annelida, Cestoda, Platyhelminthes etc.)' and use of this term is misleading to lay readers,
unnecessary for entomologists and wrong for both.

There are more general problems that seriously compromise this book. The first is one of
mistaken emphasis. Riegert states(pp. 4) “Because this is a history of entomology and not a
history of entomolgists, the present chronicle will follow insects rather than man....” is
unfortunate for it is the people who study a science that breathe the life into it: it is their ideas,
foibles, frustrations and passions that make history. Dr. Riegert’s insistence on using insects as
the main characters excludes most information that would make the people involved seem more
real. There are tantalizing anecdotes about William Downes and Eric Hearle that hint at some
interesting facets of their character but these are not pursued. The team of E.R. Buckell, A.
Dennys and A.D. Heriot are described as “the most colorful that Canadian entomology has
known” but little of this colour is brought home to the reader. I was left perplexed by this since
other historical essays by Riegert(e.g. Proc. ent.Soc. Alta. 25: 4-15) have far more personality
written into them. Questions of how the strengths, weaknesses, personalities and interactions of
these men helped (or hindered) the development of entomology are left largely unexplored.
Using insects as the focus for this book also leads to a disconcerting lack of continuity. The
narrative leaps from one insect outbreak to another and it is difficult to gain any appreciation
of the flow of events.

The second problem is one of imbalance. This is, in the main, a history of applied
entomology. Those who study insects with satiation of intellectual curiosity rather than pest
control as their goal will find little to identify with. For example, the life of F.H. Wooley Dod,
described as “one of the two leading Lepidopterists on the North American Continent”, rates
the same amount of space as an account of how a mixture of arsenic bait for grasshoppers was
prepared. At one point(Chapter 10), entomology is even forsaken for a nearly two page

681

discourse about control measures for moles and garden slugs. On the other hand, Strickland’s
building of a “world-renowned department [of entomology]” at Alberta receives less than a
page in the entire book. Acknowledged leaders in entomological education such as J.G.
Rempel(University of Saskatchewan) are dealt with in a cursory manner that borders on
gratuitous. Instead we are supplied with tiresome detail of control campaigns(proportions of
ingredients for bait mixtures, quantities of bait spread, dollar value of crops saved)that has its
place in technical reports but is of doubtful value here.

The third problem is one of omission of several important events and people. Two of the
earliest naturalists in Canada were James Isham and Alexander Graham at York
Factory(Manitoba). Neither are mentioned even though there is a very interesting story of
Graham’s data being pirated before its inclusion in Pennant’s “Arctic Zoology”. E.M. Walker’s
discovery of Grylloblatta campodeiformis near Banff, one of the major taxonomic discoveries
to be made in Canada, is not mentioned although a range extension of it by J. Gregson into
British Columbia is.

The final problem is one of editing of both text and figures. There is simply too much use of
quotes from reports of various federal entomology labs. In places(e.g., Chapter 15) perhaps one
third of the text has been written by other people. Many quotes used contain details of control
measures, crops saved, costs etc. whose omission could only enhance readability. The choice of
the 57 plates in this book is puzzling. For example, James Marshall, mentioned only at one
point in the book is shown, yet William Downes and Reginald Glendenning, each of whom
commands an entire chapter of text, are nowhere to be found. The plates are not numbered and
are grouped at the beginning of each section. Hence, any reference to them in the text is
followed by a frustrating search for the relevant illustration. Another curious anomaly is that,
except for line drawings on reproductions of posters and one picture of several hundred
mosquitoes on a fence post, there are no pictures of insects in the book. This omission is
puzzling in a book that is oriented to the insect and not the entomologist

Dr. Riegert has written a book whose cover promises more than the text delivers. The
subtitle implies a more even treatment than appears. The main title would lead a
non-entomologist to reasonably expect some insight into how scientists intimately connected
with DDT view its use and associated controversies. In fact, DDT is mentioned only four times
and then only in passing.

The word ‘history’ is 70% story. Hopefully any history will tell a story and not just recite
events. Unfortunately this book does the latter.

R.B. Aiken
Department of Entomology
The University of Alberta
Edmonton, Alberta
T6G 2E3

MATTHEWS, E.G. 1980. A guide to the genera of beetles of South Australia.
Part 1. Archostemata and Adephaga. Special Educational Bulletin Series, South Australian
Museum, Adelaide, vii + 50 pp., and 18 unnumbered plates of photographs.

Although policies of the Australian Government make it difficult for a foreign entomologist
to remove insect specimens from that country, that same Government is not opposed to

Quaest. Ent., 1980, 16(3,4)

682

encouraging excellent foreign entomologists to take up work there. Thus, we find on the staff of
the Commonwealth Scientific and Industrial Research Organization (CSIRO) and other
Australian institutions, a number of recent immigrants to the island continent, who are doing
excellent work on the indigeneous fauna. One of these entomologists is Eric G. Matthews,
curator of insects in the South Australian Museum, Adelaide. Dr. Matthews, who took his PhD
at Cornell University, with Howard E. Evans, and who subsequently immigrated to Australia,
is well known for his excellent studies of dung-using scarbaeid beetles. This present volume,
written by him, is the first in a series intended to provide a means of identifying to genus adult
beetles that inhabit the state of South Australia.

An Introduction provides a succinct history of study of Australian beetles. Statistical
information is summarized by means of a graph, plotting numbers of papers published about
beetles, against year of publication. A peak of activity is indicated in the latter part of the 19th
and first decade of the 20th Century, labelled “descriptive stage”, and followed by a decline
with its low point being the years of World War II. This is followed by a second, less
pronounced, rise in acivity, entitled the “revisionary stage”. This is a useful summary of much
information for historians of entomlogy.

The Introduction explains that this and subsequent issues deal with adults of genera and
higher taxa only, and that much remains to be learned at all levels, but especially at the species
level. Estimates of numbers of taxa are given for South Australia (1000 genera, 3200 species),
representing about 16 per cent of the Australian total. Advice is offered about study of beetles,
and two plates illustrate collecting and curating equipment and methods.

The next section includes a map of South Australia, with life zones indicated thereon. This
section also explains how the book is structured, and how it is to be used for identification of
genera. The focus is on picture keys, spread over 29 plates. These drawings are well executed,
and diagnostic features are clearly labelled. The main portion of the text is an annotated list of
names of genera and higher taxa, arranged in standard taxonomic sequence. For each genus,
the number of South Australian species is listed, along with the life zones in which specimens
have been collected. References are given by taxon to other publications, to the picture- key,
and to habitus photographs. In the equivalent space of six full pages, all of the taxa are thus
treated: Archostemata- Ommadidae (one genus); Adephaga- Carabidae (78 genera);
Haliplidae (one genus); Hygrobiidae (one genus); Dytiscidae (22 genera); and Gyrinidae (three
genera).

The photographs are sharp, and give good impressions of the habitus of adults of each genus.
Each plate has six photographs, and each photograph has a reference number and the
appropriate specific name. Size of the beetle illustrated is indicated by a number representing
length of the specimen, in millimeters.

An index to names of genera and higher taxa is provided, making it easy to locate desired
information.

The cover is stiff, gloss paper, and on the front is a colored photograph of a male of
Megacephala. The frontispiece is a color photograph of a living specimen of Calosoma schayeri
Erichson.

This volume was clearly conceived and superbly executed. It is a masterpiece of clarity and
brevity. Author, publisher, and printer are to be congratulated for producing a work that will
no doubt stimulate development of amateur entomology in Australia, and will be of use to
entomologists elsewhere who have an interest in Australian beetles.

G. E. Ball

683

EDITOR’S ACKNOWLEDGEMENTS

Pogo, the late Walt Kelly’s philosophically inclined possum friend from the great
Okefenokee Swamp, was able to demonstrate the relativity of time of occurrence of special
dates by noting that Friday the 13th did not invariably arrive on days normally designated as
Friday. In fact, it was a cause for celebration by Pogo and the other denizens of the Great
Swamp when Friday the 13th fell on Friday.

Extending this example of relativity almost to absurdity, the publishers of Quaestiones
Entomologicae have demonstrated that October, 1980 actually fell in July, 1981, for that is the
month and year of publication of Volume 16, Nos. 3 and 4-the July-October issue for 1980. I
suppose that instances such as this and variations in day of arrival of Friday the 13th are
special cases of the General Theory of Relativity.

While that explanation has appeal in the dark corridors of our publishing house, subscribers
are not likely to accept it as a reason why the issues for which they have paid good money (or a
pile of shin plasters, in Canada) have been so late in arriving. In fact, as Editor, I consider
myself lucky to be practising in an era when horsewhipping of members of my guild by
disgruntled subscribers has gone out of fashion-this form of expression of displeasure owing its
demise to a shortage of buggy whips which in turn went the way of horse-drawn vehicles.

Contributing to the time-warp alluded to above, were delays encountered in our efforts to
produce our first two issues for 1980, which included “The Hydraenidae of the Western
Hemisphere”. I am still amazed that such an elephantine volume can be devoted to
classification of such micro-lilleputian creatures. But, like Gulliver, in the land of Lilleput, we
became indeed tied down, not by anything big, but by numerous small delays and minor
problems.

It required about 19 months to produce this volume about hydraenid beetles- this being just
about the gestation period of elephants. When we saw the first bound copy, my colleagues and I
went into a state of mild euphoria, with feelings rather akin, perhaps, to those of a herd of
pachyderms when a new youngster is born and joins the troop. I am pleased to say that this 544
page elephant child was not at all wrinkled!

Three Publications Managers were involved consecutively in working on the hydraenid
volume: Mrs. Twyla Gibson, Mrs. Jane Ballash, and Mrs. Suseela Subbarao. I am grateful to
each of them for their contributions. I am especially grateful to Mrs. Subbarao, who saw to
completion the hydraenid volume, and as well the long delayed subsequent issues for 1980. The
author, Philip D. Perkins, is to be commended, too, both for his patience with our delays and for
having prepared this fine treatise.

I record appreciation of the efforts of the following, who acted at my request as referees of
papers published in Volume 16:

A. P. Nimmo, Department of Entomology, University of Alberta;

K. W. Philip, Institute of Arctic Biology, University of Alaska, Fairbanks,
Alaska;

J. R. Spence, Department of Entomology, University of Alberta; and

H. R. Wong, Environment Canada, Canadian Forestry Service, Edmonton,

Alberta.

Various members of my Department assisted with the publishing process. Jean-Francois
Landry provided French translations of several abstracts. John S. Scott helped with illustrative
matters , and he and Danny Shpeley read quantities of proof.

Quaest. Ent., 1980, 16(3,4)

In view of the long delay experienced by our loyal subscribers in receiving the issues of
Volume 16, 1 record our gratitude for patience and continued support. I cannot promise that we
will be able to get out the journal on time, once after the back-log has been cleared, but we will
do the best we can.

George E. Ball

685

INDEX

acrocnema Boloria , 562
aestivalis (Needham and
Claassen), Cultus, 669
alaskensis Holland, Boloria
napaca, 561

alberta Edwards, Boloria , 555, 562, 563,

567. 568

aliaska Bang-Haas, Colias
nastes, 558, 559
Alley, N.F., 569
Alloperla serrata Needham
and Claassen, 668
Alloperla severa (Hagen), 669
americana Lycaena phleas, 559
Anderson, R.S.,

see Donald, D.B., 666, 672, 673, 675
anicia Euphydryas, 561
arethusa , 568
arethusa Wolley-Dod,

Lycaena phleas , 555, 559, 567, 568
Arygynnis victoria, 563
assimilis Butler, Oeneis
melissa, 565

astarte Doubleday, Boloria, 555, 562,

563. 567. 568

astarte Doubleday, Boloria
astarte, 563

avara (Banks), Oecetis, 641, 642, 643,
644, 645, 646, 647, 648, 649, 650
avara Banks, Oecetina, 647
avara Banks, Setodes, 647
avinoffi Holland, Erebia
fasciata, 566

aygulus (Fabricius), Onitis, 620
badia (Hagen),

Pteronarcella, 675
balachowskyi Halffter and

Halffter, Eurysternus, 599, 601, 602,
605, 607, 608, 613, 614, 615, 616, 617,
619, 620

Banks, N., 642, 643, 644, 647, 649
Barnes, W., 563, 565
Barry, R.G., 568
Baumann, R.W., 667

Bayrock, L.A.,

see Reimchen, T.H., 569
beani Elwes, Oeneis

melissa, 555, 565, 568, 573
beani Skinner, Euphydryas

editha, 555,560,561,567,568
Belicek, J., 569,570
Benjamin, F.H.,

see Barnes, W., 555, 563
Bergstrom, G.,

see Clifford, H.F., 569
Berthelemy, C., 666
bifida Banks, Hydropsyche, 625, 626,
627,628,630, 631,632
Billings, W.D., 572
Boisduval, J.B., 559, 560, 562
Boloria acrocnema, 562
Boloria alberta Edwards, 555, 562, 563,

567, 568

Boloria astarte astarte
Doubleday, 563
Boloria astarte distincta
Gibson, 563

Boloria astarte Doubleday, 555, 562, 563,

567, 568

Boloria distincta Gibson, 562, 563
Boloria eunomia caelestis
Hemming, 563, 564
Boloria eunomia Esper, 563, 564
Boloria eunomia laddi
Klots, 563,564
Boloria eunomia nichollae

Barnes and Benjamin, 555, 563, 564,
567, 568, 573

Boloria eunomia ursadentis

Ferris and Groothuis, 563, 564
Boloria improba Butler, 561,568
Boloria improba improba
Butler, 561

Boloria improba youngi

Holland, 555, 561, 562, 568, 572, 573
Boloria napaca alaskensis
Holland, 561

Boloria napaca halli Klots, 561

Quaest. Ent., 1980, 16(3,4)

686

INDEX

Boloria napaca nearctica
Verity, 561

Boloria napaca reiffi Reuss, 555, 561,
567, 568, 573
Boloria napaea

Hoffmansegg, 561
Boloria polaris Boisduval, 562
Boloria polaris

groenlandica Skinner, 562
Boloria polaris polaris
Boisduval, 562
Boloria polaris stellata
Masters, 562

boothii Curtis, Colias, 558
bore Schneider, Oeneis, 564
borealis (Banks), Sweltsa, 668
Boydell, A.N., 569
brevicauda (Claassen),

Eucapnopsis, 675

bronta Ross, Hydropsyche , 625, 626, 627,
629, 631

brucei Edwards, Oeneis
melissa, 565
brucei Edwards, Oeneis
polixenes, 555, 566, 568
Butler, A.G., 561,565,566
Butterflies, 555
Cadbury, J.W., 560
caelestis Hemming, Boloria
eunomia, 563, 564
caffer Boheman, Onitis , 620
calif ornica (Banks),

Calineuria, 669
calif ornica Newport,

Pteronarcys, 674, 675
Calineuria californica
(Banks), 669

callias Edwards, Erebia , 567, 572
Capnia coloradensis
Claassen, 668

Capnia confusa Claassen, 675
Capnia gracilaria Claassen, 668
Capnia petila Jewett, 668
Capnia vernalis Newport, 674

caribaeus (Herbst),

Eurysternus, 599, 601, 602, 603, 605,
606, 607, 608, 609, 613, 614, 615, 616,
619

cheilonis Ross,

Hydropsyche , 626
Claassenia sabulosa
(Banks), 675
Clifford, H.F., 569
cocandicides Verity, Colias
nastes, 558
Coleoptera, 556
Colias boothii Curtis, 558
Colias hecla , 558
Colias nastes aliaska
Bang-Haas, 558, 559
Colias nastes Boisduval, 558
Colias nastes cocandicides
Verity, 558
Colias nastes moina
Strecker, 558
Colias nastes nastes
Boisduval, 558

Colias nastes rossi Guenee, 558
Colias nastes streckeri

Grim-Grschimaillo, 555, 558, 559,
567, 568

Colias nastes thula
Hovanitz, 558, 559
colonia Write, Euphydryas
editha, 560
coloradensis (Banks),

Sweltsa, 669
coloradensis Claassen,

Capnia, 668
colubrinus (Hagen),

Isogenoides, 674
columbiana (Claassen),

Utacapnia, 673, 675
confusa Claassen, Capnia, 675
Coprini, 601,607
crinita (Needham and

Claassen), Isocapnia, 668
Cultus aestivalis (Needham

687

INDEX

and Claassen), 669
Cultus tostonus Ricker, 669
Cummins, K.W., 666
Curry, D.V., 569
Curtis, J., 558, 565
dabanensis Erschoff,

Erebia, 567
Denis, M., 561
Denning, D.G., 643, 649
disjuncta (Banks), Oecetis, 641, 642, 643,
644, 646, 647, 648, 649, 650
disjuncta Banks, Oecetina , 644
distincta Gibson, Boloria, 562, 563
distincta Gibson, Boloria
astarte, 563
Dodds, G.S., 666
Donald, D.B., 666, 672, 673, 675
dos Passos, C.F., 557, 558, 563, 564, 567
Doubleday, E., 562
editha Boisduval,

Euphydryas, 560
Edwards, H., 555, 560
Edwards, J.,

see Elwes, H.J., 555, 565
Edwards, W.H., 555, 560, 562, 563, 565,
567

edwardsi dos Passos, Oeneis
bore , 555, 564, 566, 567, 568
Ehrlich, P.R., 560
elatus Denning and Sykora,

Oecetis , 642, 643
Elder, J.A., 674
Elwes, H.J., 565

Erebia callias Edwards, 567, 572
Erebia dabanensis Erschoff, 567
Erebia fasciata avinoffi
Holland, 566

Erebia fasciata butler, 566
Erebia fasciata fasciata
Butler, 566

Erebia inuitica Wyatt, 567
Erebia magdalena

mackinleyensis Gunder, 566
Erebia magdalena

magdalena Strecker, 566, 572
Erebia magdalena Strecker, 566
Erebia youngi herscheli
Leussler, 567

Erebia youngi Holland, 566, 567
Erebia youngi rileyi dos
Passos, 567
Erebia youngi youngi
Holland, 566
Erschoff, N.G., 567
Esper, E.J.C., 563
Etnier, D.A.,

see Schuster, G.A., 626, 627, 628, 629
Eucapnopsis brevicauda
(Claassen), 675

eunomia Esper, Boloria , 563, 564
Euphydryas anicia, 561
Euphydryas editha beani

Skinner, 555,560,561,567,568
Euphydryas editha
Boisduval, 560
Euphydryas editha colonia
Write, 560

Euphydryas editha lawrenci
Gunder, 560
Euphydryas editha

nubigena Behr, 560, 561
Eurysternus , 600, 601, 602, 605, 607,
608,611,618,619, 620
Eurysternus balachowskyi

Halffter and Halffter, 599,601,602,
605, 607, 608, 613, 614, 615, 616, 617,
619,620

Eurysternus caribaeus

(Herbst), 599,601,602,603,605,

606, 607, 608, 609, 613, 614, 615, 616,
619

Eurysternus foedus

Guerin-Meneville, 599,618,620
Eurysternus magnus

Laporte, 599, 601, 602, 607, 610, 61 1,
613,614,616,619
Eurysternus mexicanus

Harold, 601,605,618,619

Quaest. Ent., 1980, 16(3,4)

688

INDEX

Fabricius, J.C., 565
fasciata butler, Erebia, 566
fasciata Butler, Erebia
fasciata, 566
feildeni M’Lachlan,

Lycaena phleas, 559
Ferris, C.D., 560, 563
flexura (Claassen),

Malenka, 668
foedus Guerin-Meneville,

Eurysternus , 599,618,620
forcipata (Frison),

Paraleuctra , 668
Ford, E.B., 556
fordi dos Passos, Oeneis
bore, 564
fosketti (Ricker),

Oemopteryx, 668
frigida (Claassen), Zapada, 668
Gall, L., 562
gaspeensis dos Passos,

Oeneis bore, 564
Gaufin, A.R., , 667, 672, 675
see also Elder, J. A., 675
see also Knight, A.W., 666,672
Geyer, C., 564
Gibson, A., 563, 565
gibsoni Holland, Oeneis
melissa, 565
Gore, J.A., 674

gracilaria Claassen, Capnia, 668
grandis (Banks), Isocapnia, 668
Gregory, R.W., , 674

see Trotsky, H.M., 674
groenlandica Skinner,

Boloria polaris, 562
Groothuis, D.R.,

see Ferris, C.D., 563
Grote, A., 556
Gunder, J.D., 566
Halffter, , 605

Halffter, G., 599, 600, 601, 602, 605, 607,
608,615,618,619, 620
Halffter, V., 601,602,607,608,615

halli Klots, Boloria napaca, 561
hanbury Watkins, Oeneis
bore, 564

Hartland-Rowe, R.,

see Radford, D.S., 674
hecla Colias, 558
Hemming, F., 563
henryae Cadbury, Lyceana
snowi, 560

herscheli Leussler, Erebia
youngi, 567
Hesperoperla pacifica
(Banks), 675
Hewitson, W.,

see Doubleday, E., 555
Heymons, R., 608
Hisaw, F.L.,

see Dodds, G.S., 666
Hoffmansegg, J.C., 561
Holland, W.J., 556,561,565,566
Howe, W.H., 560,561,563
Huerta, C., 608
Hydraenidae , 5-543

Index of names, 544-554
Hydropsyche, 625, 629, 630
Hydropsyche bifida Banks, 625, 626, 627,
628,630, 631,632

Hydropsyche bronta Ross, 625, 626, 627,
629,631

Hydropsyche cheilonis
Ross, 626

Hydropsyche morosa
Hagen, 626,631
Hydropsyche recurvata

Banks, 625,626,627,628,630,631,
632

Hydropsyche walkeri

Betten and Mosely, 625, 626, 627,
628,630, 631,632
Hynes, H.B.N., , 666, 673, 675
see also Spence, J.A., 674
hypophleas Boisduval,

Lycaena phleas, 559
improba Butler, Boloria , 561, 568

689

INDEX

improba Butler, Boloria
improba , 561

integra Hanson, Isocapnia, 675
inuitica Wyatt, Erebia, 567
Isocapnia crinita (Needham
and Claassen), 668
Isocapnia grandis (Banks), 668
Isocapnia integra Hanson, 675
Isogenoides colubrinus
(Hagen), 674
Isoperla, 669

Isoperla mormona Banks, 669
Isoperla patricia Frison, 675
Jackson, L.E., 569
Kamler, E., 666
katahdin Newcomb, Oeneis
polixenes, 565
Klots, A.B., 561,563
Knight, A.W., 666,672
Kogotus nonus (Needham
and Claassen), 673
laddi Klots, Boloria
eunomia, 563, 564
Larsen, J.A., 568
lawrenci Gunder,

Euphydryas editha, 560
Leussler, R.A., 567
Lindroth, C.H., 573
Linnaeus, C., 559
L5ve, A., 568
Love, D., 557, 568, 572
Lopez, G.,

see Halffter, G., 605, 607, 608
lucilla Barnes and

McDunnough, Oeneis
melissa, 565

Lycaena phleas americana, 559
Lycaena phleas arethusa

Wolley-Dod, 555, 559, 567, 568
Lycaena phleas feildeni
M’Lachlan, 559
Lycaena phleas hypophleas
Boisduval, 559

Lycaena phleas Linnaeus, 559

Lycaena snowi Edwards, 560
Lyceana snowi henry ae
Cadbury, 560
Lyceana snowi snowi

Edwards, 555, 560, 567, 568
M’Lachlan, R., 559
Mackay, R.J., 626,631
mackinleyensis dos Passos,

Oeneis bore, 564
mackinleyensis Gunder,

Erebia magdalena, 566
magdalena Strecker,

Erebia, 566

magdalena Strecker, Erebia
magdalena, 566, 572
magnus Laporte,

Eurysternus, 599, 601, 602, 607, 610,
611,613,614,616,619
Malenka flexura
(Claassen), 668
Masters, J.H., 562
Matthews, E.G., ,601

see Halffter, G., 599,601,620
Maynard, C.J., 556
McDunnough, J.H.,
see Barnes, W., 565
Megarcys subtruncata
(Needham and
Claassen), 668

melissa Fabricius, Oeneis, 565
melissa Fabricius, Oeneis
melissa, 565
mexicanus Harold,

Eurysternus, 601,605,618,619
moina Strecker, Colias
nastes, 558
Morisset, P., 569
mormona Banks, Isoperla, 669
morosa Hagen,

Hydropsyche, 626, 63 1
Mountjoy, E.W.,

see Roed, M.A., 569, 570
napaea Hoffmansegg,

Boloria, 561

Quaest. Ent., 1980, 16(3,4)

690

INDEX

nastes Boisduval, Colias, 558
nastes Boisduval, Colias
nastes, 558

nearctica Verity, Boloria
napaca, 561
Newcomb, H.H., 565
nichollae Barnes and
Benjamin, Boloria

eunomia, 555, 563, 564, 567, 568, 573
Nicholls, , 563
Nimmo, A.P., 570
nonus (Needham and

Claassen), Kogotus, 673
nubigena Behr, Euphydryas
editha, 560,561
Nursall, J.R.,

see Patterson, C.G., 675
Oecetina avara Banks, 647
Oecetina disjuncta Banks, 644
Oecetis, 642, 650

Oecetis avara (Banks), 641, 642, 643,

644, 645, 646, 647, 648, 649, 650
Oecetis disjuncta (Banks), 641, 642, 643,
644, 646, 647, 648, 649, 650
Oecetis elatus Denning and
Sykora, 642,643
Oemopteryx fosketti
(Ricker), 668
Oeneis bore edwardsi dos

Passos, 555, 564, 566, 567, 568
Oeneis bore fordi dos
Passos, 564

Oeneis bore gaspeensis dos
Passos, 564
Oeneis bore hanbury
Watkins, 564
Oeneis bore mackinleyensis
dos Passos, 564
Oeneis bore Schneider, 564
Oeneis bore taygete Geyer, 564
Oeneis melissa assimilis
Butler, 565

Oeneis melissa beani Elwes, 555, 565,

568, 573

Oeneis melissa brucei
Edwards, 565

Oeneis melissa Fabricius, 565
Oeneis melissa gibsoni
Holland, 565
Oeneis melissa lucilla
Barnes and
McDunnough, 565
Oeneis melissa melissa
Fabricius, 565
Oeneis melissa semidea
Say, 565

Oeneis melissa semplei
Holland, 565
Oeneis polixenes brucei
Edwards, 555,566,568
Oeneis polixenes Fabricius, 565
Oeneis polixenes katahdin
Newcomb, 565
Oeneis polixenes peartiae
Edwards, 565
Oeneis polixenes polixenes
Fabricius, 565
Oeneis polixenes subhyalina
Curtis, 565
Oeneis polixenes

yukonensis Gibson, 565
Oeneis taygete Geyer, 564
Oniticellini, 601
Onitini, 601,620
Onitis , 620

Onitis aygulus (Fabricius), 620
Onitis caffer Boheman, 620
Onthophagini, 601
Onthophagus , 605, 608
pacifica (Banks),

Hesperoperla, 675
pacificum (Banks),

Taenionema , 675
Packer, J.G., 569,571
pallidula (Banks),

Suwallia, 675
Paraleuctra forcipata
(Frison), 668

691

INDEX

parallela (Frison), Skwala, 675
Parnassiius eversmanni
thor H. Edwards, 558
Paterson, C.G., 675
patricia Frison, Isoperla, 675
peartiae Edwards, Oeneis
polixenes, 565
Perlomyia utahensis

Needham and Claassen, 668
petila Jewett, Capnia, 668
Phanaeus, 608

phleas Linnaeus, Lycaena, 559
Plecoptera, 665

polaris Boisduval, Boloria, 562
polaris Boisduval, Boloria
polaris, 562

polixenes Fabricius, Oeneis, 565
polixenes Fabricius, Oeneis
polixenes, 565
Pteronarcella badia
(Hagen), 675
Pteronarcys californica
Newport, 674, 675
Radford, D.S., 674
recurvata Banks,

Hydropsyche, 625, 626, 627, 628,
630,631,632
Reeves, B.O.K., 569
reiffi Reuss, Boloria

napaca, 555,561,567,568,573
Reimchen, T.H., 569
Ricker, W.E., 675
rileyi dos Passos, Erebia
youngi , 567
Ritchie, J.C., 572
Robinson, D.J., 671
Roed, M.A., 569,570
Ross, H.H., 626, 642, 648, 649
rossi Guenee, Colias nastes, 558
Rowe, J.S., 667
Rutter, N.W., , 569

see also Roed, M.A., 569, 570
Ryan, J.K., 556
sabulosa (Banks),

Claassenia, 675
Say, T., 565
Scarabaeinae, 605
Scarabaeini, 601
Schiffermuller, I., 561
Schneider, D.H., 564
Schuster, G.A., 626, 627, 628, 629
semidea Say, Oeneis
melissa, 565
semplei Holland, Oeneis
melissa, 565
serrata Needham and

Claassen, Alloperla, 668
Setodes avara Banks, 647
severa (Hagen), Alloperla, 669
signal a (Banks), Triznaka, 675
Skinner, H, 562
Skwala parallela (Frison), 675
Smith, R.E.,

see Robinson, D.J., 671
snowi Edwards, Lycaena, 560
snowi Edwards, Lyceana
snowi, 555, 560, 567, 568
sopladora Ricker, Utaperla, 669
Spence, J.A., 674
Sperling, F., 562
Stalker, A.McS., 569
stellata Masters, Boloria
polaris, 562
Strecker, F.H., 566
streckeri

Grim-Grschimaillo,

Colias nastes, 555, 558, 559, 567, 568
subhyalina Curtis, Oeneis
polixenes, 565
subtruncata (Needham and
Claassen), Megarcys, 668
Suwallia pallidula (Banks), 675
Sweltsa borealis (Banks), 668
Sweltsa color adensis
(Banks), 669
Sykora, J.,

see Denning, D.G., 643
Taenionema pacificum

Quaest. Ent., 1980, 16(3,4)

692

INDEX

(Banks), 675 Zapada frigida (Claassen), 668

taygete Geyer, Oeneis , 564
taygete Geyer, Oeneis bore , 564
thula Hovanitz, Colias
nastes , 558, 559
tostonus Ricker, Cultus, 669
trava (Nebeker and

Gaufin), Ut acapnia, 675
Triznaka, 669

Triznaka signata (Banks), 675
Trotsky, H.M., 674
Udvardy, M.D.F., 568
ursadentis Ferris and
Groothuis, Boloria
eunomia, 563, 564
Utacapnia Columbiana
(Claassen), 673, 675
Utacapnia trava (Nebeker
and Gaufin), 675
utahensis Needham and

Claassen, Perlomyia , 668
Utaperla sopladora Ricker, 669
vernalis Newport, Capnia , 674
victoria Arygynnis, 563
Vitt, D.H.,

see Packer, J.G., 569, 571
xvalkeri Betten and Mosely,

Hydropsyche , 625, 626, 627, 628,

630,631,632
Ward, J.V., 674, 675
Warren, B.C.S., 561
Watkins, H.T.G., 564
Whittaker, R.H., 667
Wiggins, G.B., 666
Wolley-Dod, F.H., 559
Wright, W.G., 572
Wyatt, C.W., 563, 567
youngi Holland, Boloria

improba, 555, 561, 562, 568, 572, 573
youngi Holland, Erebia, 566, 567
youngi Holland, Erebia
youngi, 566

yukonensis Gibson, Oeneis
polixenes, 565

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