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RECEIVED BY GIFT FROM

Uarch 11, 1959

A Revision of the SPIDER MITE Family Tetranychidae

A REVISION OF THE

SPIDER MITE

FAMILY TETRANYCHIDAE

A. EARL PRITCHARD AND EDWARD W. BAKER

MEMOIRS SERIES
VOLUME 2

1955

SAN FRANCISCO

PACIFIC COAST ENTOMOLOGICAL SOCIETY

Published and sold by
THE PACIFIC COAST ENTOMOLOGICAL SOCIETY
California Academy of Sciences, Golden Gate Park,

San Francisco 18, California

Printed with the assistance
of the H. C. Fall
Memorial Publication Fund

Edited by: P. D. Hurd, Jr.
Designed by: John B. Goetz

Preface

The history of development of our knowledge of animal groups follows
a uniform pattern. First there is the problem of identification, usually
beginning with description of new forms. This is followed by first attempts
at a classification. Then regional systematic treatments appear. Finally
a monograph becomes possible, based on the accumulated work of many
people.

Curiously, the mites have not followed this precise pattern. Because
of their economic importance, mites have long attracted attention. Much
has been written on these small but numerous and widely distributed
arthropods. \et for years scientists did little to further knowledge of the
systematics of mites. Only recently have new species been described
in precise terms and old species redescribed adequately. Now the time
is propitious for monographic treatment, and it is indeed fortunate that
two such outstanding specialists as Professor A. Earl Pritchard and
Dr. E. W. Baker have dedicated themselves to the job and have chosen
the group that is most destructive to agricultural crops, the spider mites.
In the following pages the authors have not only considered all previous
work in the group, but they have gone to original sources of type speci¬
mens and living material in the museums of North America and Europe and
the type localities of two continents. The revision of the Tetranychidae
presented in this book not only provides the essential information re¬
quired by economic entomologists, but also provides illustrations of a
caliber seldom equalled in taxonomic work and a sound classification
for the use of taxonomists.

G. W. W harton,

Professor and Head and

Director of the Institute of Acarologv

Department of Zoology
University of Maryland
College Park, Maryland

Contents

Introduction . 1

Collection of samples . 2

Slide preparation . 2

Acknowledgments . 3

Systematics of the Tetranychidae . 4

Morphology . 6

Key to the subfamilies . 11

Subfamily Bryobiinae . 12

Key to the tribes . 14

Tribe Bryobiini . 14

Tribe Hystrichonychini . 35

Tribe Petrobiini . . 42

Subfamily Tetranychinae . 96

Key to the tribes . 96

Tribe Tenuipalpoidini . 97

Tribe Eurytetranychini . 100

Tribe Tetranychini . 124

Literature Cited . 447

Index of Host Plants . 462

Index of Spider Mites . 467

Introduction

1 lie family 1 etranycliidae contains many species that tire important pests
of agriculture. Practically all the major food crops and many ornamental
plants are subject to attack. Especially during the past decade, a great
deal of experimental work has been directed toward the control of these
mites and a consideration of the particular species involved has become
important.

The only comprehensive publications on the taxonomy of the family
l etrany chidae in North America are by Hanks (1900), McGregor (1919),
and McGregor (1950). The last mentioned article is monographic in
scope, and it is a noteworthy contribution.

A study of the taxonomy of European tetranychids has been con¬
sidered only on a localized basis, but more recent papers by Hirst (1920)
for England, Vitzthum (1929) for Germany, and Geijskes (1939) for
Holland are worthy of mention. Womersley (1940) reviewed the knowledge
of this family in Australia.

Heck (1947-1952) has been making important studies on the spider
mites of Georgia, S.S.H., but we have seen only a few of his papers.

This is the first comprehensive treatment of the species of the world,
and it is the over-all picture of the Tetranychidae with which we are
primarily concerned. The recognition of subfamilies and tribes is in¬
tended to show phylogenetic relationships within the family, and the
new interpretations of genera and the recognition of species groups are
intended to further delineate these relationships.

A study of the taxonomy and nomenclature of tetranychids must be
conducted on a world-wide basis. Man has undoubtedly transported many
of the more omnivorous species throughout the world, and these mites
are adjusting to new hosts in new geographical locations.

The present revision is largely synoptic, and the diagnoses and
illustrations are presented for ready identification. There are undoubt¬
edly a great many species that are undescribed, even as there are de¬
scribed species that cannot be recognized readily from the literature
and species complexes that cannot be readily resolved on a morpho¬
logical basis.

[1]

2

Spider Mites

Collection of Samples

When it is possible to bring infested plant material into the laPoratory,
it is easy to ascertain that both sexes are obtained for study by select¬
ing the specimens individually with the aid of a dissecting microscope.

In the field adequate samples of heavy infestations are often obtained
by placing infested leaflets into wide-mouthed vials of alcohol. With
lighter infestations, and particularly with conifers, it is practical to
beat the plant material over a Boudreaux funnel — a hand funnel equipped
with a wire screen at the top and bearing a vial of alcohol at the spout
to catch the specimens (Boudreaux, 1954). Care must be taken that
specimens are not left clinging to the sides of the funnel. A slower
method is to beat the plant material over an enameled pan and remove
the mites individually with a fine camel’s-hair brush.

For collecting mites that feed on grass, the Berlese funnel is very
practical. Heat, often in the form of an electric light bulb over the
large funnel, is used to drive the mites from the plant material over a
period of several days.

Slide Preparation

We have attempted the use of many mounting media for spider mites,
including Canada balsam, Clarite, Euparol, Hyrax, polyvinyl alcohol
(with lactic acid and phenol), methyl cellulose (Clark and Morishita,
1950), and glycerine. Hover’s modification of Berlese’s mounting medium
has proved to be the most satisfactory. It is true that this is not a
permanent mounting medium, but specimens may be remounted if nec¬
essary.

Our formula of Hoyer’s is prepared by mixing in the following se¬
quence:

Distilled water . 50 grams

Gum arabic (flakes) .... 30 grams

Chloral hydrate . 200 grams

Glycerine . 20 grams

Specimens may be mounted directly into Hoyer’s medium, either alive
or from alcohol. Males must be oriented laterally for study of the aedea-
gus. An oil-immersion lens is necessary for critical study of spider
mites, and the phase attachment is invaluable for detailed observations.

3

Introduction

Acknowledgments

A large number of entomologists have contributed material for this study,
and vve have attempted to name the collectors whenever individual col¬
lections are cited. We have particularly credited colleagues throughout
the world who were able to respond to our requests for needed material,
with the gift of specimens collected by them or by the loan of types,
lo all of these cooperators we are indeed grateful.

We also acknowledge our appreciation to Frederick Cunliffe, of the
Pinellas Biological Laboratory, for travel grants enabling survey work
on the tetranychoid and other mites of Florida.

Dr. Josef lv. Winkler, Charles University, Prague, Czechoslovakia,
has been particularly helpful in obtaining otherwise unavailable articles
by recent Russian workers. Dr. Schozo Fhara, Hokkaido University,
Sapporo, Japan, has also located for us Japanese articles unavailable
in the U.S.A; moreover, he has been kind enough to make translations.

It is, indeed, a pleasure to work with acarologists internationally,
each scientist being anxious to contribute unselfishly to an advancement
of our knowledge of mites.

Systematics of the
TETRANYCHIDAE

FAMILY TETRANYCHIDAE DONNADIEU

I ETRANYCHIDES Donnadieu, 1875, Recher. Serv. Hist. Tetranych., p. 9.
TETRANYCHIDAE Murray, 1877, Econ. Ent. Aptera, pp. 93, 97; Kramer,
1877, Archiv. Naturg., 43(2): 225, 228; Trouessart, 1891, Rev.
Sci. Nat. Ouest, 1: 289, 308; Berlese, 1897, Acari Myr. Scorp.
Prostig., pp. 7, 8, 51; Oudemans, 1897, Tijd. Ent., 40: 120;
Banks, 1900, U. S. Dept. Agr., Div. Ent. Tech. Ser., 8: 70; Banks,
1907, Proc. U. S. Natl. Mus., 32: 598; Ewing, 1909, Univ. Ill.
Bui., 7(14): 35; Oudemans, 1910, Bui. Ent. Res., 1: 112; Vitzthum,
1913, Mikrokos., 6: 99, 108; Banks, 1915, U. S. Dept. Agr. Rep.,
108: 32; Ewing, 1929, Man. Ext. Parasites, pp. 20, 28; Vitzthum,
1929, Tierw. Mitteleur., 3(Lief 7): 47; Vitzthum, 1931, Handb.
Zoo 1 . , 3(1, 3): 145; Geijskes, 1939, Meded. L andbouvvh. Wagen-
ingen, 42(4): 11; Carman, 1940, Bui. Conn. Agr. Exp. Sta., 431:
67; Womersley, 1940, Trans. Roy. Soc. S. Australia, 64(2): 234;
Vitzthum, 1942, Klass. Ordn. Tierr., 5(Abt. 4, Buch 5): 809;
McGregor, 1950, Amer. Midi. Nat., 44(2): 257; Radford, 1950,
Check List Mite Gen. and Type Spp., Intern. Union Biol. Sci.
Ser. C. (Sect. Ent.), 1, p. 76; Reck, 1950, Irudy Inst. Akad.
Nauk Gruz. S.S.R., 9: 117; Baker and Wharton, 1952, Intr. Acar.,
p. 211; Reck, 1952, Izd. Akad. Nauk S.S.R. 1952: 3.

Tetr AN^ CHINI Canestrini and hanzago, 1878, Atti Reale 1st. Veneto Sci.
Let. Arti (ser. 5), 4: 148; Canestrini, 1889, Atti Reale 1st. Ven.
Sci. Let. Art. (ser. 6), 7: 491.

TETRANYCHINA Berlese, 1886, Acari Dann. Piante Colt., p. 16.

The taxonomic revisions of TragWh (1915), Zacher (1916, 1933),
McGregor (1919), and I garov and Nikolskii (1937) refer to the family
only by a common name.

[4]

S rystematics of the l etranychidae

Concepts of the family 1 etranychidae have undergone considerable
evolution since the group was first given a suprageneric name in 1875.
Only two genera, Tetranychus Dufour and Bryobia Koch were recognized
prior to thut time, and to the former genus had been assigned a number
of species of predaceous mites properly belonging to several families
of the Prostigmata, Hven Donnadieu, in the dissertation proposing the
family name, considered eriophyids to be immature stages of tetrany-
chids, and some contemporary workers believed daggers to represent
their young.

Predaceous mites properly belonging to several genera of the
Haphignathidae were once included in tetranychid genera, and the rhapig-
nathid genus N eophyllobius Berlese, 1886, was only recently removed
from the 1 etranychidae (McGregor, 1950).

The genus II eteronychus Canestrini and Fanzago, 1876, was referred
by the original authors to the family Tetranychidae. 1 he species on
which the genus was based has not since been recognized. The descrip¬
tion of the coloration of the mite and the setation of the legs is entirely
inconsistent with our knowledge of the tetranychids, being, perhaps,
more like that of a member of the genus N eophyllobius.

During recent years the tetranychoid mites have been segregated into
separate units of family status. The latest and most comprehensive
comparative treatment of these family categories is by Baker and
Pritchard ( 1953). l’he genera Tenuipalpus Donnadieu, Brevipalpus Donna¬
dieu, Phy top tip alp us Tragardh, Pseudoleptus Bruyant, Raoliella Hirst,
and Tegopalpus Womersiey, all previously referred to the Tetranychidae,
are now placed in the family Phytoptipalpidae. Similarly Tuckerella
Womersiey is now placed in the Tuckerellidae.

The superfamily Tetranychoidea (Reck, 1952b; Baker and Pritchard,
1953) consists of those prostigmatic mites having the paired basal seg¬
ments of the chelicerae fused into a pouch-like lobe called a stylophore;
within the latter are anchored the curved proximal ends of the movable

Fig. I. Stylophore and chelicerae of a tetranychid mite ( Tetranychus telarius).

6

Spider Mites

digits or stylets (fig. 1). In the family 1 etranychidae, the fourth palpal
segment bears a strong “claw” and the dorsum of the bod) bears not
more than 16 pairs of setae. These obvious characteristics will separate
the tetranychids from all other mites.

MORPHOLOGY

Mites of the family Tetranychidae bear two obvious types of setae
(fig. 2): tactile and chemosensory (see Grandjean, 1948). The former are

l ig. 2. Sensory, tactile, and duplex setae of a tetranychid
mite ( Yetranychus telarius, female).

7

Systematics of the / etrnny chidae

Fig. 3. Anterior portion of propodosoma of a tetranychid showing
location of the peritremes ( Eotetrany chus uncatus).

slender, finely pointed, with thick walls, and bearing pubescence. The
latter have thin walls in which transverse striations may be evident,
and they are nude. The chemosensory setae are referred to as sensorv
setae for convenience, dhe sensory setae are sometimes distinguished
as to whether they are slender and tapering or else slender and broadly
rounded at the distal end or fusiform.

A third type of seta, found on the tarsal appendages, is characterized
by having a knob or hook at its distal end. Setae of this type are referred
to as tenent hairs. They are always found on the claw, and usually a
number of tenent hairs are amalgamated distally, each appearing to
originate from a number of roots. Tenent hairs are also found on the
empodium of the more generalized tetranychids, as in related tetrany-
choids, but they are replaced by tactile hairs in higher forms.

The tetranychid palpus, bears a nearly constant number of setae. The
dorsal seta on the second palpal segment of the male is usually swollen,
and the terminal sensillum on the fifth palpal segment of the male is
usually more slender than in the female. Seven setae occur on the fifth
segment: three are tactile and four are sensory. Of the latter, the prox¬
imal one is fusiform, two are tapering, and the terminal sensillum is
usually well developed and rounded at the tip but rarely reduced or
absent.

The development of the stylophore is similar among various genera,
but an anteromedian cleft may represent a species differentiation.

8

Spider Mites

Fig. 4. Types of true claws found in the Tetranychidae: A.) Tetrany cop sis
horridus (an individual claw is shown); B.) ttryobia drummondi ; C.) Aplonobia
acharis; D. ) Oligonychus ununguis.

The peritremes (fig. 3) consist of a pair of arms that arise medially
near the anterior end of the body and diverge over the surface of the
protrusible stylophore. The oil-immersion lens will sometimes suffice to
demonstrate that these “tubes” are open dorsally as observed by
Blauvelt (1939). The ends of the peritremes are anastomosing sacs of
tracheae in the most generalized tetrany chids. In the higher species they
usually end simply but each may terminate in a simple bulb, or have
several distal chambers and be simply hooked, or else the distal end
is irregular or anastomosing.

The dorsum of the tarsus of leg I of the adult bears two pairs of
intimately associated setae, a characteristic of the family Tetranychidae
(except in one tribe where the close relationship of both pairs of setae
is not apparent). These setae are termed the duplex setae (fig. 2). One
pair of duplex setae is found on the dorsum of tarsus II. Development
and placement of the duplex setae are sometimes valuable for species
differentiation but more often serve for recognition of species groups
or higher categories. The distal and comparatively long member of each
duplex is sensory, and the proximal member is tactile.

9

Systematics of the Tetranychidae

1 he legs possess sensory setae, other than those of the duplexes,
on all tarsi, the anterior tibiae, and sometimes tibiae 11-1 V. Other leg
setae on all segments are tactile, lhe number of setae on a given tibia
or tarsus mu.y be variable, but in many cases the tactile or else the
sensory setae will independently be constant in number; usually both
numbers are constant. In contrast to other prostigmalic mites, the sen¬
sory setae are more apt to be variable.

lhe tarsal appendages consist of a pair of true claws laterally and
u central empodium. Iheir evolutionary development is of considerable
taxonomic value (fig. 4).

The claw is primitively clawlike or else padlike, and with latero-
ventral tenent hairs. Trag&rdh (1915) first demonstrated that the higher
tetranychids possess a claw derived from this type. The lateroventral
tenent hairs of each claw form separate rows in T etranycopsis, but they
are fused distally to form one or several pairs in Bryobia. The distal
end of the claw disappears; and the proximal portion of the remaining
claw is slender in relatives of Petrobia, but it is strongly reduced in
higher forms, leaving mainly the pair of tenent hairs.

The dorsal texture of the integument of the body of a tetranychid
varies considerably. It is smooth, except for large folds in some of the
more generalized forms. There may be a development of mediodorsal
areas bearing areolate or punctate impressions on the propodosoma and
opisthosoma. However, the higher tetranychids bear integumentary
stnations, irregular and widely spaced in some species but similar to
that of a finger-print pattern in most. The striae may be characteristically
dotted or else solid.

lhe chaetotaxy of the body of a spider mite is of tribal and generic
significance. Only two genera have four pairs of dorsal propodosomal
setae, the rest three. Three genera have nine pairs of dorsolateral and
dorsosublateral hysterosomal setae. Other genera have only seven pairs
of dorsolateral and dorsosublateral hysterosomal setae.

The hysterosoma always bears three pairs of setae mediodorsally,
and these are called the dorsocentrals (fig. 5). Laterad of the first
pair of dorsocentrals are two setae on each side: the outermost is called
the humeral and the inner is the first dorsolateral. Laterad of each of
the second and third dorsocentrals is a pair of setae in certain of the
more generalized tetranychids. One member of each of these pairs of
lateral setae may occupy a sublateral position, or else it is absent in
the higher forms.

Caudad of the dorsocentral hysterosomals, there are three pairs of
setae, the posterior, inner pair being the clunals. This interpretation
differs from that of Oudenians and our own earlier work (Pritchard and

10

Spider Mites

Fig. 5. Dorsum of body of a tetranychid showing nomenclature of the setae.

Baker, 1952) in which the clunals were regarded as being either present
or absent (the caudal setae that drop out are now regarded as being the
post-anals). The two pairs of setae between the clunals and the dorso-
centrals are conveniently referred to as the sacrals inasmuch as they
may be marginal in some of the lower forms or else the inner pair re¬
sembles a fourth pair of dorsocentrals in higher forms.

Chaetotaxy of the venter is constant within the family, except for
the opisthosoma. Females of the higher tetranychids have two pairs
rather than three pairs of anal setae, and males have four pairs rather
than five pairs of genito-anal setae. Certain genera of the tribe Tetrany-
chini have the caudal set of the two pairs of para-anal setae displaced
(fig. 6) to appear as a terminal pair of dorsal setae (the post-anals), and
these setae are lacking in two genera.

11

Systemutics of the 1 etrany chidae

Fig. 6. Venter of body of a tetranvchid showing nomenclature of the setae.

Taking into consideration other characters that represent a more
generalized morphological structure within the family, it is thus evident
that a reduction in the number of body setae is indicative of phylogenetic
development.

Key to subfamilies of Tetranychidae

1. Empodium with tenent hairs; female with three pairs of anal setae
and male with five pairs of genito-anal setae (fig. 7) .

. Bryobiinae (p. 12)

1. Empodium (rarely appearing absent) without tenent hairs, female
with two pairs of anal setae and male with four pairs of genito-
anal setae (fig. 7) . T ETRANY' CHIN A E (p. 06)

I

Subfamily

BRYOBIINAE

Berlese

Bryobiini Berlese, 1913, Acaroth. Ital., p. 17.

Bryobiinae Reck, 1950, Trudy Inst. Zool. Akad. Nauk Gruz. S.S.R.,
9: 122; Reck, 1952, Izd. Akad. Nauk S.S. R. 1952: 24.

Bryobiidae Reck, 1952, Soobsh. Akad. Nauk Gruz. S. S. R.. 13(7): 422.

The subfamily Bryobiinae contains the most generalized members of
the family. None of the species is known to produce silken strands.

The true claws are well developed in Bryobia and Tetranycopsis but
each is reduced to a small but slender pad bearing a pair of distal tenent
hairs in the other genera. The pad, however, is better developed than in
the I etranychinae and represents an intermediate stage in its reduction.

The peritremes each have a glomerate, elongate or saccular termina¬
tion or, in some cases, the distal end is simple or else reflexed and
multilobed.

The character of the duplex setae is distinctive of the subfamily.
They are always placed at the abruptly declivate distal end of the tar¬
sus, and the proximal member of each pair is minute and straight.

The most generalized species possess four pairs of dorsal pro-
podosomals whereas others have three pairs of dorsal propodosomals.
The hysterosoma bears twelve pairs of dorsal setae in the more general¬
ized species and ten pairs of dorsal setae in the higher Bryobiinae.

1 he female bears three pairs of anal setae and the male has five pairs
of genito-anal setae (fig. 7).

[12]

13

Subfamily Bryobiinae Herlese

Fig. 7. Opisthosomal venters showing setation of the genital areas of the
Bryobiinae: A.) female of P etrobia harti\ FO male of P. harti\ and the Tetrany-
chinae: C.) female of TeUanychus telarius ; and D.) male of 7. telarius.

14

Spider Mites

Key to tribes of Bryobiinae

1. Propodosoma with four pairs of dorsal setae; true claw long and
with tenent hairs mediolaterally .... BRYOBIINI (p. 14)

1. Propodosoma with three pairs of dorsal setae; true claw a short

but slender pad with a pair of terminal tenent hairs ... 2

2. Hysterosoma with five pairs of dorsolateral and dorsosublateral

setae (with twelve pairs of dorsal hysterosomals) .

. Hystrichonychini (p. 35)

2. Hysterosoma with three pairs of dorsolateral setae (with ten pairs
of dorsal hysterosomals) . PeTROBIINI (p. 42)

TRIBE BRYOBIINI RECK

Bryobiinae Reck, 1952, Soobsh. Akad. Nauk Gruz. S.S.R. 13(7): 423.

The tribe Bryobiini is characterized by having four pairs of dorsal
propodosomals and the true claw is developed as a curved hook or a
long pad, with lateral tenent hairs. There are twelve pairs of dorsal
hysterosomals.

Key to the genera of Bryobiini

1. True claw uncinate, with one or several pairs of mediolateral

tenent hairs . Bryobia (p. 14)

1. True claw padlike, with two rows of ventrally directed tenent
()airs . T etranycopsis (p. 34)

GENUS BRYOBIA KOCH

Bryobia Koch, 1836, Deuts. Crust. Myr. Arachn., 1: 8, 9; Koch, 1838,
Deuts. Crust. Myr. Arach., 17: 11; Koch, 1842, Uebers. Arach,
Syst., 3: 31; Canestrini and Fanzago, 1878, Atti Reale 1st. Veneto
Sci. Let. Arti (ser. 5), 4: T18; Berlese, 1886, Acari Dann. Piante
Colt., p. 24; Canestrini, 1889, Atti Reale 1st. Veneto Sci. Let.
Arti (ser. 6), 7 : 494, 505; Oudemans, 1905, Tijd. Ent., 48: 242;

15

Subfamily Bryobiinae Berlese

Banks, 1907, Proc. U. S. Natl. Mus., 32: 598; Ewing, 1909, Univ.
Ill. Bui., 7(14): 52; Banks, 1915, U. S. Dept. Agr. Hep., 108: 34;
Ewing, 1921, Proc. U. S. Natl. Mus., 59(2394): 661; Vitzthum,
1929, 'lierw. Mitteleur., 3(7): 48; Oudemans, 1930, Ent. Ber.
8(176): 172; Oudemans, 1937, Krit. Hist. Overz. Acar., 3(C): 1063;
Geijskes, 1939, Meded. Landbouwh. Wageniugen, 42(4): 14;

Womersley, 1940, 1 rans. Hoy. Soc. S. Australia, 64(2): 23;

McGregor, 1950, Amer. Midi. Nat., 44(2): 364; Hadford, 1950,
Syst. Check List Mite Gen. and lype Spp. Ser. C. (Sect. Ent.),
1: 76; Baker and Wharton, 1952, Introd. Acar., p. 213. Type of
genus: Bryobia praetiosa koch, by present designation ( B . speci-
osa, the t)pe designated by Koch and that usually cited, was
not originally included).

Sannio Scheuten, 1857, Arch. Naturg., 23: 104. Type of genus: ( Sannio
rubrioculus Sheuten) = Bryobia praetiosa; monobasic.

Torynoph'ora Cambridge, 1876, Proc. Zool. Soc. Lond., 168: 258. Type
of genus: ( Torynophora serrata Cambridge) = Bryobia praetiosa;
monobasic.

Schmiedleinia Oudemans, 1930, Ent. Ber., 7(181): 290. Type of genus:

( Schmiedleinia tiliae Oudemans) = Bryobia praetiosa Koch;
monobasic.

P seudobryobia McGregor, 1950, Amer. Midi. Nat., 44(2): 355. Type of
genus: P seudobryobia bakeri McGregor, by original designation.
New synonomy.

McGregor (1950) proposed the generic name P seudobryobia for those
species of Bryobia in which the distal enlargement of the peritreme
is not obviously slender and protruding from the body. This character
is not valid for generic distinction inasmuch as the distal enlargement
of the peritreme of Bryobia praetiosa is usually slender but is some¬
times broadly rounded, and the peritreme is not protruding when the
stylophore is protracted.

The arrangement of the more lateral dorsal hysterosomal setae is
subject to displacement among the various species. The setae laterad
of the three pairs of hysterosomal dorsocentrals are arranged in dorso-
sublateral and lateral rows in Bryobia curiosa and B. bakeri; they form
a single lateral row in B. praetiosa and B. cristata; and they are inter¬
mediate in B. drummondi and B. sarothamni.

Trag&rdh (1904a, 1904b) considered Acarus denticulatus Linnaeus,
1758, to be a prior name for Bryobia praetiosa. However, Oudemans
(1937) and others refer this Linnaean species to the family Labidos-
tommidae; and the name is here given no further consideration.

All of the described species of Bryobia are included in the following

16

Spider Mites

treatment, but two of the recognized species are not known from North
America.

17

Subfamily Bryobiinae Berlese

1.

1.

2.(1).

2.(1).

3.(1).

3. (1).

4. (3).
4.(3).

i. (3).

Fig. 9. Bryobia curiasa : dorsal aspect of propodosoma.

Key to the species of BRYOBIA

Einpodia Il-IV each consisting of a pair of tenent hairs . . 2

Empodia II-IV padlike, each with two ventrally directed rows
of tenent hairs . 3

Stylophore cleft mediodistally; body with dorsal setae obviously

spatulate . curiosa (p. 19)

Stylophore convex distally; body with dorsal setae lanceolate
. bakeri (p. 19)

Propodosoma with anterior two pairs of setae arising directly
from dorsum; body with dorsal setae slender even if subclavate

. 4

Propodosoma with anterior two pairs of dorsal setae arising from
strong projections; body with dorsal setae short and broadly
spatulate . 5

Empodium I consisting of a pair of tenent hairs; propodosomal

dorsum striate . drummondi (p. 19)

Empodium I consisting of a short pad with ventral rows of tenent

hairs; propodosomal dorsum dotted, with smooth reticulations
. sarothamni (p. 20)

Empodium I consisting of a short pad with ventral rows of tenent

hairs; males common . cristata (p. 22)

18

Spider Mites

Fig. 10. Bryobia bakeri: dorsal aspect of female, type.

5.(3). Empodium I consisting of a single pair of tenent hairs; males
unknown . praetiosa (p. 26)

19

Subfamily Bryobiinae Berlese

Bryobia curiosa Summers
(Figures 8, 9)

Bryobia curiosa Summers, 1953, Ann. Ent. Soc. Amer., 46: 290. Type:
femule, Mojave Desert, California, on unknown host; in the IJ. S.
National Museum.

Adults of Bryobia curiosa may be recognized among other members
of the genus by the sharply cleft stylophore. I he adults resemble those
of B. baheri in that the empodia each consists of only a pair of tenent
hairs. However, the dorsal setae of the body are broadly spatulate rather
than being lanceolate as in B. bakeri, and there are four small projec¬
tions anteriorly on the propodosoma.

1 his species is indigenous to the desert region of southern Califor-
nia, although its host is unknown. Ihe only collection is that of the
types from the Mojave Desert, California, beaten from mostly composite
desert plants.

Bryobia bakeri (McGregor), new combination
(Figures 10, 11)

P seudobryobia bakeri McGregor, 1950, Amer. Midi. Nat., 44(2): 366
Type: female, Mt. Popocatapetl, Mexico, 12,000 ft., from trunk
of pine; in the U. S. National Museum.

Bryobia bakeri resembles B. curiosa in that the empodia each con¬
sists of a single pair of tenent hairs. However, the stylophore of B.
bakeri is not cleft, and the dorsal setae of the body are slender and
lanceolate.

This species is known from the type specimen from Mt. Popocatapetl
near Mexico City, and from a female, Texas (R. K. Fletcher) on wheat.
The latter specimen is smaller than the type, and the sensory setae on
the tarsi are also shorter.

Bryobia drummondi (Ewing), new combination
(Figures 12, 13, 14)

Petrobia drummondi Ewing, 1926, Ent. News, 37: 143. Type: female,
Death Valley, California, on creosote bush; in the U. S. National
Museum.

P seudobryobia drummondi, McGregor, 1950, Amer. Midi. Nat., 44(2): 368.

20

Spider Mites

Fig. 11. Bryobia bakeri: tarsus I of female.

Bryobia drummondi may be recognized by having no cephalic propodo-
somal projections; empodium I consisting only of a pair of tenent hairs;
and empodia II to IV padlike, one-half as long as the claws. The dorsal
setae of the body are slender, and the dorsum of the body is striate.

This species is indigenous to the arid southwestern United States.
It is found commonly in that region on creosote bush, Larrea tridentata.

Collections studied, other than the type, are from Little Rock,
California, (E. W. Baker), on Larrea tridentata; Lucerne Valley,
(A. E. Pritchard), on Larrea tridentata; Old Woman Springs, California
(A. E. P ritchard), on Larrea tridentata; Pearblossom, California
(A. E. Pritchard), on Larrea tridentata; and \sleta, Texas (P. J.
Netterville), on Larrea tridentata.

Bryobia sarotbamni Geijskes
(Figure 15)

Bryobia sarothamni Geijskes, 1939, Meded. Landbouwh. Wageningen,
42(4): 14. Types: female, male, nymph, and larva, Holland, from
Sarothamnus vulgaris; possibly in the Laboratorium voor Entomol-
ogie, Landbouwhoogeschool te Wageningen, Holland.

Bryobia sarothamni may be recognized by having no cephalic projec¬
tions on the propodosomal dorsum and by having all the empodia padlike,
as long as the claws, and bearing two ventrally directed rows of tenent
hairs. The dorsal integument of the body is distinctive in being retic¬
ulate, and, the dorsal setae are lanceolate.

I his species is possibly common in Europe, although it was recog¬
nized only recently. Numerous specimens studied in connection with
this revision were collected at East Mailing, Kent, England. (A. M.
Massee), on Cytisus sp.

21

Subfamily liryobiinae Herlese

Fig. 12. Bryobia drummondi : dorsal aspect of female, Little flock, California.

22

Spider Mites

B.) distal end of peritreme of female; C.) tarsus I of male; D.) duplex setae of
tarsus II of female; E.) tarsus I of female.

Bryobia cristata (Duges)

(Figures 16, 17, 18)

Tetranychus cristatus Duges, 1834, Ann. Sci. Nat. Paris (ser. 2), 1: 15,
28; Oudemans, 1937, Krit. Hist. Overz. Acar., 3 (C): 1064;
Geijskes, 1939, Meded. Landbouwh. Wageningen, 42(4): 17. De¬
scribed from males and females from Paris, on numerous hosts
and under stones.

Bryobia cristata, Oudemans; 1905, Ti j d. Ent., 48: 242; Oudemans, 1906,
Ent. Her., 2: 60; Oudemans, 1937, Krit. Hist. Overz. Acar.,
3 (C): 1065.

Bryobia praetiosa, Womersley (not Koch, 1836), 1940, Trans. Roy. Ent.

Soc. S. Australia, 64(2): 246. Misidentification.

Bryobia urticae Sayed, 1946, Bui. Soc. Fouad ler Ent., 30: 86. Types:
males and females, Dokki near Cairo, Egypt, on Urtica urens and

23

Subfamily Hryobiinae Herlese

Fig. 14. Bryobia drummondi : dorsal aspect of male, Little Rock, California,

with lateral view of aedeagus.

24

Spider Mites

other weeds; probably in the collection of M. T. Sayed. New
synonymy.

Bryobia borealis Oudemans, 1930, Skrift. Sval. Isharet Oslo, 27: 102.
Types: females, Hiortham, Iceland, under boards and stones;
probably in the Rijksmuseum van Natuurlijke Historie, Leiden,
Holland. New synonymy.

Although Oudemans considered cristata Duges to be a prior name for
praetiosa Koch, Geijskes did not accept the synonymy because Duges
described males. Geijskes noted that males of Bryobia praetiosa were
unknown in Europe, except for the Duges reference.

Duges’ description, however, obviously refers to a species of Bryobia,
and because he described the male in such detail, even observed in
copulation, his scientific name should be applied to the close relative

Fig. 1F>. Bryobia sarothamni: dorsal aspect of female, England.

25

Subfamily Bryobiinae Berlese

of B. praetiosa in which males are common. Even though this species
has not been recognized subsequently in Europe (except for Iceland),
the description of B. urticae Sayed shows that the species occurs in
the palaearctic region. B. cristate cannot be considered as an earlier
name for B. sarothamni, because of the very long front legs of the female.

Bryobia cristata resembles B. praetiosa in that the first two pairs
of dorsal propodosomals are borne on cephalic projections, and the

Fig. 17. Bryobia cristata, female: above, tarsus II; and below, tarsus I.

dorsal setae of the female body are subspatulate. However, the empodium
of tarsus I of the adult female consists of a short stub bearing two rows
of ventrally directed tenent hairs, and males are common. The dorsal
setae of the body appear to be somewhat more slender. Otherwise, fe¬
males of the two species are difficult to distinguish.

Bryobia cristata as thus recognized is known from Europe and North
Africa, Australia, and Japan. Specimens studied by us are from Japan
(intercepted in Seattle, Washington, by Bureau of Entomology and Plant
Quarantine personnel), on chrysanthemums.

Bryobia praetiosa Koch
(Figures 19, 20)

Acarus graminum Schrank, 1781, Beytr. Natur., p. 8; Oudemans, 1906,
Ent. Ber., 2: 60; Oudemans, 1929, Krit. Hist. Overz. Acar., 2: 289.
Be scribed from specimens from Germany, on grass.

Bryobia graminum, Oudemans, 1929, Krit. Hist. Overz. Acar., 2: 289;

Oudemans, 1937, Krit. Hist. Overz. Acar., 3(C): 1067.

Bryobia denticulata, Tragardh* 1904, Zool. Anz., 27: 565. Misidenti-
fication.

Bryobia praetiosa Koch, 1836, Deu. Crust. Myr. Arach., 1: 8; Canestrini
and Fanzago, 1878, Atti Heale 1st. Veneto Sci. Let. Arti (ser. 5),
4: 91; Berlese, 1886, Acari. Dann. Piante Colt., p. 24; Canestrini,
1889, Atti Heale 1st. Veneto Sci. Let. Arti (ser. 6), 7: 505;

27

Subfamily liryobiinae fieri ese

Fig. 18. Bryobia cristata: dorsal aspect of male, Japan,
with dorsal view of aedeagus.

Oudemans, 1900, Tijd. Ent., 43: 138; Oudemans, 1905, Tijd.
Ent., 48 : 242; Oudemans, 1906, Ent. Ber., 2: 60; Trag&rdh, 1914,
Meddel. Centralanst. Forsoks. Jordbruck, 92: 3; Zacher, 1916,
Mitt. kais. biol. anst. Land. — Forstw., 16: 23; Oudemans, 1927,
Ent. Ber., 7: 259; Tragardh, 1928, Rep. Sci. Res. N orveg. Exped.
Nov. Zemlya, 40: 7; Vitzthum, 1929, Tierw. Mitteleur., 3(7): 48;
Oudemans, 1930, Ent. Ber., 8: 172; Oudemans, 1937, Krit. Hist.

28

Spider Mites

Overz. Acar., 3(C): 1069; Geijskes, 1939, Meded. Landbouwh.
Wageningen , 42(4): 16; Garnian, 1940, Conn. Agric. Expt. Sta.
Bui., 431: 69; Andre, 1941, Bui. Mus. Natl. Hist. Nat. Paris
(ser. 2), 13: 430; Reck, 1947, Soobsh. Acad. Nauk Gruz. S.S.R. ,
8(7): 653; McGregor, 1950, Amer. Midi. Nat., 44(2): 365. Described
from specimens from Germany on shrubbery.

Bryobia gloriosa Koch, 1836, Deu. Crust. Myr. Arachn., 1: 9. Described
from specimens from Germany, in fields.

Bryobia speciosa Koch, 1838, Deu. Crust. Myr. Arachn., 17: 10;
Oudemans, 1905, Tijd. Ent., 48: 242; Oudemans, 1912, Ent. Ber.,
3: 273; Oudemans, 1937, Krit. Hist. Overz. Acar., 3(C): 1070.
Described from specimens from Germany, in woods.

Bryobia nobilis Koch, 1838, Deu. Crust. Myr. Arachn., 17: 11; Oudemans,
1937, Krit. Hist. Overz. Acar. (Gedeelte 3), C: 1069. Described
from specimens from Germany; no host given.

Rhyncholophus haustor Hardy, 1850, Ann. Mag. Nat. Hist. (ser. 2), 6(33):
182. Described from specimens from England, on grasses and
fruit trees.

Bryobia haustor , Oudemans, 1937, Krit. Hist. Overz. Acar., 3(C): 1067.

Torynophora serrata Cambridge, 1876, Proc. Zool. Soc. Lond. 168: 258.
Described from specimens from Kerguelen Land, Indian Ocean,
under stones.

Bryobia pratensis Garman, 1885, Fourteenth Rep. State Ent. Illinois,
p. 73; Riley and Marlatt, 1890, Ins. Life, 3: 45; Banks, 1915,
U. S. Dept. Agr. Rep., 108: 34. Described from females, Illinois,
on grass.

Bryobia weyerensis Packard, 1889, Cave Memoir, p. 42. Described from
Weyer’s Cave, Virginia.

Bryobia glacialis Packard (apparently a nomem nudum, since we have not
been able to find a reference to this species in Packard’s articles,
even though this is listed as a new species in the Zoological
Record for 1889).

Bryobia pallida Garman, 1885, Fourteenth Rep. State Ent. Illinois, p. 74;
Riley and Marlatt, 1890, Ins. Life, 3: 74. Described from nymphs,
Illinois, on grass.

Bryobia ribis Thomas, 1896, Zts. Pflanzenk., 6: 80. Described from
specimens from Germany, on Grossularia sp.

Bryobia glacialis Berlese, 1913, Redia, 9: 78. Type : probably nymph,
Sandrio, Italy (no host given); probably in the Berlese collection
at Florence, Italy.

Bryobia brevicornis Ewing, 1921, Proc. U. S. Natl. Mus., 59(2394): 662.
Types: females, Arizona, on alfalfa; in the U. S. National Museum.

29

Subfamily Hry obiinae Herlese

Fig. 19. Bryobia praetiosa : dorsal aspect of female, Los Alamos, New Mexico.

30

Spider Mites

Fig. 20. Bryobia praetiosa : appendages of tarsi II and IV.

Bryobia longicomis Ewing, 1921, Proc. U. S. Natl. Mus., 59(2394): 662.
Types: females, Ashland, Nebraska, from Dutchman’s breeches,
Bikukulla cucullana; in the U. S. National Museum.

Bryobia humeralis Halbert, 1923, Jour. Linn. Soc. Zool., 35: 385. Types:

females, Ireland, on garden walls and moss.

Schmiedleinia tiliae Oudemans, 1930, Ent. Ber., 7(176): 291. Types:
larvae, Berlin Dahlem, Germany, on Tilia sp.; probably in the
Rijksmuseum van Natuurlijke Historic, Leiden, Holland.

Bryobia praetiosa, as here identified, may be differentiated from other
members of the genus by having strong anterior propodosomal projections
and by having empodium I of the adult female consisting of a single
pair of tenent hairs (a short empodial pad with several pairs of ventrally
directed tenent hairs is present on this segment in the nymphs), Empodia
II to IV are padlike, about as long as the claws, and with two rows of
ventrally directed tenent hairs. Dorsal setae of the body are short and
broadly spatulate. Males are unknown.

Oudemans (1905, 1927, 1937) considered the praetiosa complex to
consist of at least two species, although he once (1900, 1906) con¬
sidered the forms as being merely physiological races. Tragardh (1914)
considered Bryobia praetiosa to be a single, variable species, and
Vitzthum (1929) stated that although specimens collected from enumer¬
ated hosts appear to be different species, still no morphological dis¬
tinctions are evident.

Geijskes (1939) also pointed out that Bry'obia praetiosa is not a
sharply delineated species. He postulated that there must exist a number
of probable subspecies or races on different hosts. Geijskes observed
that the anterior legs of the female bear more setae on specimens col¬
lected from certain hosts and that populations on different hosts differ
biologically, particularly in regard to overwintering habits. He was

31

Subfamily Bryobiinae Berlese

unable to separate the forms morphologically and recognized no similar
species in Holland.

McGregor (1950), without further comment, considered certain of
the species described from North America ( Bryobia pallida was disre¬
garded), as well as the European B. speciosa, to be synonyms of B.
praetiosa.

Hoosje and Van Dinther (1953) recently reviewed the taxonomy und
biological considerations of this mite in Holland. They found that popu-
lat ions from ivy transfer readily to the same host and to Zinnia e It gans;
but their transfers from ivy to gooseberry, red clover, and European
boxwood were all negative.

Morphological distinctions are evident among collections of Bryobia
praetiosa that are taken from different types of hosts. The most obvious
differences are in the length of the fore legs of the female, accompanied
by variations in the number of tactile setae on tibia I: from 11 to 17
in the specimens studied, lhese setae are not always constant on a
single specimen, nor are these numbers correlative with a given host.

Females from England, California, and Chile — all from apple — appear
to have the distal enlargement of the peritreme shorter and more globular
(not projecting anteriorly when the stylophore is protracted). Other
specimens have the peritremal enlargement slender and usually project¬
ing. However, no sharp morphological distinctions are evident with this
character, when all specimens are studied.

Summers (1952) made a detailed study of the biology of Bryobia
praetiosa on California almonds. His findings differ considerably from
the observed behavior of this mite on other types of plants and sub¬
stantiate the observations by Geijskes (1939) and others that seasonal
development may vary according to host.

It is evident, therefore, that there are a number of subspecies or
species in the Bryobia praetiosa complex and that a morphological dis¬
tinction of the various populations and their further delineation nomen-
claturally is extremely difficult. In view of the fact that these mites
are entirely parthenogenic, one might expect that a single mutation could
give rise to a clone and subsequent population that differs to some extent
from the parent, at least with regard to host relationships, biological
development or minor morphological characters. It is very difficult to
ascertain whether such mutations represent actual species differences,
since reproductive isolation is always present.

In the meantime, the taxonomist can recognize only Bryobia praetiosa
with its long list of synonyms. Bryobia graminum is undoubtedly a
prior name, but its proposed use is withheld pending further studies on
the species complex.

32

Spider Mites

Specimens of Bryobia praetiosa have been studied from Europe,
Turkey, South Africa, North America, South America, and Australia.

Deciduous fruit trees such as apple, pear, plum, prune, cherry, peach,
and nectarine are important hosts. Almond is a favorite host, and walnut
is reported to be a host. Wild or native grasses commonly harbor the
mite, as well as wheat, barley, and other grains. Clover and alfalfa are
occasionally infested. Many weeds are favorable hosts. Ornamentals
such as ivy, orchids, and shade trees are also subject to infestation.

Bryobia praetiosa commonly invades homes in both Europe and North
America, particularly during the fall.

Bryobia amygdali Reck

Bryobia amygdali Reck, 1947, Soobsh. Akad. Nauk Cruz. S.S.R., 8(9-10):
658. De scribed from specimens from Georgia, S.S.R., on Rhamnus
pallasii.

This and all of the following species described by Reck are presumed
to belong to the praetiosa complex, because his keys identify the species
by the anteromedian projections of the propodosoma, length of legs, type
of setae on femora I, and coxae I setation.

Bryobia go riensis Reck

Bryobia goriensis Reck, 1947, Soobsh. Akad. Nauk Gruz. S.S.R., 8(9-10):
656. Described from specimens from Gori, Georgia, S.S.R., on
Rubus sp.

Bryobia longisetis Reck

Bryobia longisetis Reck, 1947, Soobsh. Akad. Nauk Gruz. S.S.R.,
8(9-10): 655. Described from specimens from Georgia, S.S.R., on
Salvia spp.

Bryobia osterloffi Reck

Bryobia osterloffi Reck, 1947, Soobsh. Akad. Nauk Gruz. S.S.R., 8(9-10):
657. Described from specimens from Georgia, S.S.R., on Astragalus
caucasicus.

33

Subfamily Rryobiinae fierlese

Fig. 21. Tetranycopsis horridus : dorsal aspect of female, California.

Bryobia parietariae Reck

Rrvobia parietariae Reck, 1947, Soobsh. Akad. Nauk Gruz. S.S.R.,
8(9-10): 660. Described from specimens from Georgia, S.S.R., on
Parie taria judaica.

34

Spider Mites

Bryobia redikorzevi Reck

Bryobin redikorzevi Reck, 1947, Soobsh. Akad. Nauk Gruz. S.S.R.,
8(9-10): 658. Described from specimens from Georgia, S.S.R., on
Prunus spinosa.

Bryobia ulmophila Reck

Bryobia ulmophila Reck, 1947, Soobsh. Akad. Nauk Gruz. S.S.R., 8(9-10):
659. Described from specimens from Georgia, S.S.R., on Ulmus sp.

GENUS TETRANYCOPSIS CANESTRINI

T etranycopsis Canestrini, 1889, Atti Reale Istit. Veneto Sci. Let. Arti
(ser. 6), 7: 494, 504; Geijskes, 1939, Meded. Landbouwh. Wagen-
ingen, 42: 26. Type of genus: Tetranychus horridus Canestrini
and Fanzago; monobasic.

Tetrany chops is, Berlese, 1893, Acari Myr. Scorp. Prostig., 72: No. 8.
Emendation for T etranycopsis Canestrini.

The genus T etranycopsis may be recognized by having the claws
long and padlike, each with two rows of short, ventrally directed tenent
hairs. The empodium resembles the claws. Similar tarsal appendages are
found elsewhere only in the Linotetranidae and the Phytoptipalpidae.

A single species of Tetranycopsis has been definitely recognized.
Four species have been erroneously assigned to the genus: T. simplex
Iraglirdh, T. spinosa Banks, T. histricina Berlese, and T. paupera
Berlese. The status of T. spiraeae Reck has not been determined.

Tetranycopsis horridus (Canestrini and Fanzago)

(Figure 21)

Tetranychus horridus Canestrini and Fanzago, 1876, Atti Soc. Veneto-
Irentino Sci. Nat., 5: 139; Canestrini and Fanzago, 1878, Atti
Reale Istit. Veneto Sci. Let. Arti (ser. 5), 4: 151; Berlese, 1887,
Acari Myr. Scorp. Prostig., 36: No. 9; Reck, 1948, Trudy Zool.
Inst. Akad. Nauk Gruz. S.S.R., 8. Described from specimens from
Italy, on unspecified host.

35

Subfamily Hryobiinae Herlese

Neophyllobius horridus, Herlese, 1886, Acari Dunn. Piante Colt., p. 20.
Tetranycopsis horrida, Canestrini, 1889, Atti Reale 1st. Veneto Sci.
Let. Arti (ser. 6), 7: 504.

Tetranychopsis horrida, Herlese, 1893, Acari Myr. Scorp. Prostig.,
72: No. 8.

I etrany copsis horridus, Geijskes, 1939, Meded. Landbouwh. Wageningen,
42(4): 26.

Tetranycopsis horridus is a very distinctive spider mite with long
dorsal setae that are borne on strong tubercles. It feeds typically on
the upper surface of the leaves of hazel, Corylus maxima, in south¬
eastern Lurope. However, Canestrini and Fanzago, as well as Herlese,
recorded additional hosts.

This species was known only from Italy until Hirst and Reck recorded
its occurrence on hazel in England and Georgia, S.S.R. respectively.

A moderate but persistent infestation occurs near Niles, California,
on hazel trees imported many years ago from Europe.

Tetrarrycops is spiraeae Reck

Tetranycopsis spiraeae Reck, 1948, Trudy Zool. Inst. Akad. Nauk
Gruz. S.S.R. , 8. Described from specimens from Georgia, S.S.R. ,
on Spiraea hypericifolia.

Vie have not seen the article in which this species was described.

HYSTRICHONYCHINI PRITCHARD AND BAKER, NEW TRIBE

The tribe Hystrichonvchini is rather intermediate between the Bry-
obiini and the Petrobiini, although it is more closely allied to the latter
group. The hysterosoma possesses nine pairs of dorsolateral and dorso-
sublateral setae in addition to the three constant pairs of dorsocentrals,
as in the Bryobiini; but there are only three pairs of dorsal propodo-
somals. Moreover, the true claw consists of a slender pad bearing a
pair of tenent hairs distally. The empodium consists of a pair of tenent
hairs.

36

Spider Mites

Kig. 22. hystrichonychus gracilipes : dorsal aspect of female, Texas.

37

Subfamily Rryobiinae fierlese

Fig. 23. Hystrichonychus gracilipes : above, tarsus I of male with lateral
enlargement of appendages; below, tarsus 1 of female with dorsal enlargement
of appendages.

GENUS HYSTRICHONYCHUS McGREGOR

Hystrichonychus McGregor, 1950, Amer. Midi. Nat., 44(2): 272. Type
of genus: 7 etranychus gracilipes Banks; monobasic and by orig¬
inal designation.

A eotetranycopsis Bagdall, 1951. New synonymy. The original description
of this genus has not been seen; the new synonymy is based on
the key presented by Reck (1952a).

The genus Hystrichonychus is known to us only from the southwestern
and western United States. It contains two species that feed on members
of the family Malvaceae in the southwestern United States.

A third species was described by Bagdall (1951) from Armenia,
S.S.R., but we have not seen this description nor the specific name
proposed.

38

Spider Mites

Fig. 24. hystrichonychus gracilipes : dorsal aspect of male, Texas.

39

Subfamily Bryobiinae Berlese

Key to the species of H YSTRICHON YCHUS

1. Peritreme terminating in a very complex enlargement; dorsal

setae of body stout, nearly blunt di stall y . . . gracilipes (p.39)

1. Peritreme hooked distally, but sometimes irregularly sub¬

branched; dorsal setae of body slender, tapering to a fine point .
. sidae (p.40)

Hystrichonychus gracil ipes (Banks)

(Figures 22, 23, 24, 25)

l etranychus gracilipes Hanks, L900, U.S. Dept. Agr. l ech. Ser., 8: 72.
Types: females, Phoenix, Arizona, on Sphaeralcea; in the U. S.
National Museum.

Hystrichonychus gracilipes, McGregor, 1950, Amer. Midi. Nat., 44(2):
272.

Hystrichonychus gracilipes may be recognized by having the dorsal
setae of the body stout, set on strong tubercles, and the distal end of
the peritreme consisting of a complex enlargement.

This species, as here defined, is known only from Sphaeralcea in the
southwestern United States. Aside from Banks’ types, collections have
been studied from El Centro, California, (E. A. McGregor), on Sphaeral¬
cea angusti folia; and Tsleta, Texas (P. Netterville), on mallow.

Fig. 25. Hystrichonychus gracilip es, peritremes: A.) male, Texas;
B.) female, type; C.) female, Texas.

40

Spider Mites

Fig. 26. Hystrichonychus sidae: dorsal aspect of female, holotype.

Hystrichonychus sidae Pritchard and Baker, new species

(Figures 26, 27)

Hystrichonychus sidae is very closely allied to //. gracilipes. It
differs by having the body with comparatively slender and more tapering
dorsal setae, and the distal end of the peritreme is comparatively simple.
Moreover, H. sidae occurs only on alkali mallow, Sida hederacea.

Female. — Rostrum very slender, reaching middle of genu 1. Palpus
slender, the claw of the fourth segment surpassing the fifth segment;

41

Subfamily Bryobiinae Berlese

P ig. 27. Hystrichony chus sidae: peritreme of male and aedeagus.

terminal sensilla slender. Peritreme with several distal chambers forming
a strong hook (sometimes with lobulate diverticula). Legs with slender,
tapering, pubescent, tactile setae. Anterior legs about as long as body;
tarsus I with one dorsal pair and three ventral pairs of tactile setae
proximad of duplex setae and with a pair of medioventral sensory setae.
Empodium a single pair of divergent tenent hairs, about one half as
long as the pair of tenent hairs on the true claw. Body with fine, mostly
transverse striae on integument; propodosoma with the three pairs of
dorsal setae similar to the twelve pairs of dorsal hysterosomals, all
very long, slender, tapering from near the base, sparsely serrate, and
set on strong tubercles. Length of body, 353 ft ; with rostrum, 500 p.

Male. — Similar to female except tarsus I with three pairs of sensory
setae proximad of the duplex setae, and the dorsum of the body with
all of the setae shorter than the first three pairs of dorsocentral hystero¬
somals. Aedeagus slender but stout and curved dorsad to the dorsally
directed, tiny, distal angulation. Length of body 300 p ; with rostrum,
366 g.

Holotype. — Female, Modesto, California, August 8, 1949 (A. E.
Pritchard), on alkali mallow, Sida hederacea; type no. 2075 in the U. S.
National Museum. Paratypes. — Six males, 2 females, Corcoran, Califor¬
nia, August 6, 1951 (A. E. Pritchard), on Sida hederacea; 1 male, 4
females, 5 nymphs, August 31, 1948, August 31, 1948 and 8 males, 25
females, 2 nymphs, Modesto, California August 8, 1949 (A. E. Pritchard),
on Sida hederacea; and 7 males, 9 females, Tracy, California, May 26,
1949 (J. W. MacSwain), on Sida hederacea.

42

Spider Mites

TRIBE PETROBIINI RECK

Petrobiinae Reck, 1952, Soobsh. Akad. Nauk Gruz. S.S.R., 13(7): 423.

The tribe Petrobiini differs from other tribes of the Bryobiinae in
that the hysterosoma possesses only five pairs of dorsolateral and
dorsosublateral setae. In other words, the second and third dorsolaterals
are single, rather than paired. In many of the species, the inner sacrals
are placed medially to resemble a fourth pair of dorsocentral hystero-
somals; but in other cases they are marginal so that the mite has three
pairs of caudal setae.

The true claw resembles that of the tribe Hystrichonychini. It con¬
sists of a small, slender pad that bears a pair of tenent hairs distally.
The empodium may consist of a slender pad bearing many pairs of tenent
hairs; but it may be only a small pad or even reduced to just a single
pair of tenent hairs.

Key to the genera of Petrobiini

1. Empodium uncinate . 2

1. Empodium without a terminal hook, being padlike or else con¬
sisting of a pair of tenent hairs . 3

2. Empodium with two rows of ventrally directed tenent hairs

. P etrobia (p. 42)

2. Empodium with one pair of mediolateral, distally directed tenent

hairs . Schizonobia (p. 56)

3. Hysterosoma with inner sacrals approximate and resembling a

fourth pair of dorsocentrals . Aplonobiaip. 58)

3. Hysterosoma with inner sacrals more widely spaced than dorso¬
centrals and more removed from them than the dorsocentrals
are from each other . Monoceronychus (p. 74)

GENUS PETROBIA MURRAY

P etrobia Murray, 1877, Econ. Ent., Apt., p. 118; Oudemans, 1915, Ent.
Ber., 4(83): 193; Oudemans, 1915, Arch. Naturg. 81(A,5): 48;
Vitzthum, 1929, Tierw. Mitteleur., 3(7): 49; Geijskes, 1939, Med-
ed. Eandbouwh. Wageningen, 42(4): 27; Womersley, 1940, Trans.

43

Subfamily Hryobiinae Herlese

Fig. 28. P etrobia harti : dorsal aspect of female.

Roy. Soc. S. Australia, 64(2): 254; McGregor, 1950, Amer. Midi.
Nat., 44(2): 363. Baker and Wharton, 1952, Introd. Acarol., p. 213;
Baker and Pritchard, 1953, Hilgardia, 22(7): 206. Type of genus:
( Trombidium lapidum Hammer) = P etrobia latens (Muller), by
original designation and monobasic.

Tetranobia Banks, 1917, Ent. News, 28: 194. Type of genus: (Tetranobia
decepta (Banks)) - P etrobia latens (Muller); monobasic.
Tetranychina Banks, 1917, Ent. News, 28: 195; McGregor, 1950, Amer.
Midi. Nat., 44(2): 360. Type of genus: Tetranychina apicalis
Banks; monobasic. Sew synonymy.

44

Spider Mites

Fig. 29. P etrobia harti : peritreme and tarsus I of female, with
enlargement of tarsal appendages.

Tenuicrus Womersley, 1940, Trans. Roy. Soc. S. Australia, 64(2): 250.
Type of genus : (Tenuicrus errabundus Womersley) = Petrobia harti
(Ewing); monobasic. New synonymy.

Neobryobia Reck, 1941, Soobsh. Akad. Nauk Gruz. S.S.R., 2(8). Type of
genus: ( Neobryobia spectabilis Reck) = Petrobia harti (Ewing).
New synonymy.

Petrobia may be recognized by having an uncinate empodium bearing
two rows of ventrally-directed tenent hairs.

The genus Tetranychina is here considered to be a synonym of Pet¬
robia, because the only distinction that has been made between the
two genera is in the termination of the peritreme: elongate and protruding
when the stylophore is retracted in Petrobia, and more globular in
Tetranychina. A study of the genus Bryobia showed that this single
character is of no value for generic consideration in that group, and in
the absence of supplementary characters, the termination of the peritreme
is similarly considered to be of no generic value in this related group
of mites. Neobryobia was considered by Reck (1950) to be a synonym
of Tetranychina.

Petrobia drummondi Ewing is now known to belong to the genus
Bryobia.

45

Subfamily Bryobiinae Herlese

Key to the species of PETROBIA
Females

1. Body with dorsal setae much longer than intervals between them
and set on tubercles . 2

1. Body with dorsal setae shorter than intervals between them and

and not set on tubercles . 3

2. C.lunal setae shorter than other dorsal hysterosomals; anterior

legs much longer than body . hard (p. 45)

2. Clunal setae similar in length to. other dorsal hysterosomals;
anterior legs about as long as body .... lupini (p. 47)

3. Sacrals distinctly longer than other dorsal hysterosomals .

. apicalis (p. 49)

3. Sacrals similar in length to other dorsal hysterosomals

. latens (p. 51)

Petrobia hard (Ewing), new combination
(Figures 28, 29, 30)

N eophyllobius hard Ewing, 1909, Trans. Amer. Ent. Soc., 35: 405.
Type: female, Carbondale, Illinois, on moss; in the U. S. National
Museum.

letranychina hard, Banks, 1917, Ent. News, 28: 195; Garman, 1940,
Bui. Conn. Agr. Exp. Sta., 431: 73; McGregor, 1950, Amer. Midi.
Nat., 44(2): 363.

letranychina macdonoughi McGregor, 1917, Proc. U. S. Nat. Mus., 51
(2167): 588; McGregor, 1950, Amer. Midi. Nat., 44(2): 361. Types:
males and females, Quincy, Florida, on Oxalis stricta; in the
U. S. National Museum. New synonymy,
letranychina tuberculata Kishida, 1921, Dobutsugaku Zasshi, 33: 449.
Described from a female, Tokyo, Japan, from human urine. New
synonymy.

T enuicrus errabundus Womersley, 1940, Trans. Roy. Soc. S. Australia,
64(2): 251. Type: female, Concord West, New South Wales, on
ground; probably in the South Australian Museum. New synonymy.
Neobrxobia spectabilis Reck, 1941, Soobsh. Akad. Nauk Gruz. S.S.R.,
2(8); Reck, 1948, Trudy Zool. Inst. Akad. Nauk Gruz. S.S.R., 8.
Described from specimens from Suchumi, Georgia, S.S.R., on
Oxalis comiculata.

46

Spider Mites

enlargement of aedeagus.

47

Subfamily H ryobiinae Herlese

Tetranychina age rati Sayed, 1946, Bui. Soc. Kouad ler tint., 40: 83.
types: females, Dokki, near Cairo, Egypt, from Ageratum con y-
zoidis and Petunia hybrida; probably in the collection of M. T.
Sayed. !\eiv synonymy.

temales of Petrobia harti may be recognized by having the body with
long dorsal setae that are set on strong tubercles, the clunal setae
being obviously shorter than the others. Ihe male is distinctive in
having the first pair of dorsocentral hysterosomals comparatively long
and slender and the second to “fourth” (the inner sacrals) pairs short
and lanceolate. 1 he anterior legs are very long in adults of both sexes,
about twice as long as the body in the female and about three times as
long as the body in the male.

Tenuicrus errabundus (Australia), Tetranychina agerati (Egypt), and
Tetranychina tuberculata (Japan) are considered by us to be synonyms
of Petrobia harti. There is nothing in the illustrations accompanying
the original descriptions of these species to indicate a difference from
specimens that are found commonly on Oxalis in scattered parts of the
United States. T. macdonoughi is also considered to be a synonym of
P. harti inasmuch as no reliable difference has been found between
Ewing’s type of harti and other specimens studied. The synonymy of
Tetranychina spectabilis is based on the host.

In view of the fact that Petrobia harti feeds primarily on members
of the genus Oxalis, there has been a question as to whether specimens
recorded from other hosts, such as clover, ageratum, and petunia, may
not represent other species that form a complex with P. harti. However,
it has been noted in greenhouses and nurseries in the San Francisco Bay
area that specimens may be found on many other hosts when Oxalis
is present as a weed.

Collections of this species have been studied from Maryland, Florida,
Alabama, Mississippi, Illinois, and California.

Petrobia lupini ( McGregor), new combination

(Figures 31, 32, 33)

T etrany china lupini McGregor, 1950, Amer. Midi. Nat., 44(2): 362. Types:
males and females, Oxnard, California, on Lupinus arboreus; in
the U. S. National Museum.

P etrobia lupini is closely allied to P. harti and resembles that spe¬
cies in having the body with long dorsal setae that are set on strong
tubercles. However, the anterior legs are shorter, about as long as the

48

Spider Mites

Fig. 31. Petmbia lupini: dorsal aspect of female, type.

49

Subfamily Hryobiinae lierlese

Fig. 32. P etrobia lupini : peritreme and tarsus I of female.

body in the female and about twice as long as the body in the male.
Moreover, the clunal setae are as long as the other dorsal hysterosomals.

Ihis spider mite is known only from lupines on the California coast.
The types were collected on Lupinus arboreus in southern California.
Other material has been collected near Montara on the San Francisco
peninsula (A. E. Pritchard), on Lupinus varicolor.

Petrobia apicalis (Banks), new combination
(Figures 34, 35, 36)

T etrany china apicalis Banks, 1917, Ent. News, 28: 195; McGregor,
1950, Amer. Midi. Nat., 44(2): 360. Types: females, St. Bernard,
Louisiana, on white clover; in the U. S. National Museum.

Adults of Petrobia apicalis may be readily recognized and distin¬
guished from Petrobia latens, which they resemble, by having very short,
slender setae on the body except that the sacrals are obviously longer.
The anterior legs are about as long as the body in the female, about
twice as long as the body in the male.

50

Spider Mites

Fig. 33. P etrobia lupini: dorsal aspect of male, with
lateral enlargement of aedeagus.

51

Subfamily firyobiinae Hertese

Fig. 34. Petrobia apiccdis ■ dorsal aspect of female, Louisiana.

4^

x. -

/

Petrobia apicalis is found on legumes in the southeastern United
States. Specimens have been studied from Louisiana, Mississippi, and
Georgia, on clover, peas, and vetch.

Petrobia latens ( Muller )

(Figures 37, 38)

Acarus latens Miiller, 1776, Zool. Dan. Prodr., p. 187. Described from
specimens from Denmark, under stones.

52

Spider Mites

Fig. 35. Petrobia apicalis- tarsus I of female.

Petrobia latens, Oudemans, 1915, Arch. Naturg. , 81(A, 5): 44; Oudemans,
1929, Krit. Hist. Overz. Acar., 2: 285; Womersley, 1940, Trans.
Roy. Soc. S. Australia, 64(2): 254; McGregor, 1950, Amer. Midi.
Nat., 44(2): 364; Baker and Pritchard, 1953, Hilgardia, 22(7): 206.

Acarus praegnans Schrank, 1781, Ins. Austr., p. 520. Described from
specimens from Austria, on soil.

Acarus petrarum Fourcroy, 1785, Ent. Paris, 2 : 529. Described from
specimens from France, on soil.

Trombiaium lapidum Hammer, 1804, in Hermann, Mem. Apt., p. 49. De¬
scribed from specimens from Germany, on stones.

Petrobia lapidum, Oudemans, 1915, Arch. Naturg., 81: (A, 5): 49; Geijskes,
1939, Meded. Landbouwh. Wageningen, 42(4): 27.

Tetranychus anauniensis Canestrini, 1889, Atti Reale 1st. Veneto Let.
Sci. Arti (ser 6), 7: 503. Described from specimens from Italy,
under stones.

T etrany chops is simplex Tragardh, 1904, Zool. Exp. Egypt White Nile
1901, 20(1): 8. Types: females from Egypt, under stones; probably
in the Tragardh collection.

T etrany chop sis paupera Berlese, 1910, Redia, 6: 346. Types: female
and several nymphs, Cansiglio, Italy, under wood. New synonymy.

Tetranychus longipes Banks, 1912, Proc. Ent. Soc. Wash., 14: 97; Ewing,
1913, Ann. ,Ent. Soc. Amer., 6: 460. Types: females, Springer,
New Mexico, on Agropyron sp., as well as California; in the
U. S. National Museum.

Tetranobia decepta Banks, 1917, Ent. News, 28: 194. Types: females,
Mesa, Arizona, on barley; in the U. S. National Museum.

T etrany china tritici Ewing, 1921, Proc. U. S. Natl. Mus., 59(2394):
665. Types: females, Idaho, on wheat; in the U. S. National
Museum.

53

Subfamily Rryobiinae Rerlese

Fig. 36. Petrobia apicalis : dorsal aspect of male, Louisiana,
with lateral enlargement of aedeagus.

54

Spider Mites

Fig. 37. Petrobiu latens : dorsal aspect of female.

55

Subfamily Hryobijnae H erlese

Fig. 38. Petrobia latens : tarsus I of female, with
enlargement of appendages.

Petrobia cephae Sayed, 1946, Bui. Soc. Fouad ler Ent., 30: 79. Types:
females, Upper Egypt, on onions; probably in the collection of
M. 1 . Sayed.

Petrobia latens may be readily recognized by having a clawlike
empodium and the dorsal setae of the body all short, slender, and similar
in length. The anterior pair of legs is much longer than the body. It
further differs from other members of the genus by having the peritremal
enlargement slender, and by having the dorsum of the body with contin¬
uous but minutely crenulate striae rather than with dotted striae.

This species reproduces parthenogenetically, and males are unknown.
Eggs that are destined to hatch quickly are red and spherical, radially
striate dorsally and with a short dorsal stipe. However, eggs that serve
for dormancy are coated with a white material, including a circular,
radially striate cap (as first illustrated by Hammer, 1804). The dormant
eggs are laid on stones and other debris, and do not hatch until condi¬
tions are favorable for the growth of new annual grasses. An individual
female lays only one type of egg (Fenton, 1951).

Petrobia latens feeds primarily on monocotyledonous plants such as
grasses, wheat, barley, sorghum, onions, gladiolus, and iris, ^hen
large populations build up on grasses, the mites migrate and may feed
on other hosts. Damage has been reported to cotton, carrots, lettuce,
and melons. Alfalfa, bur clover, and apple are other recorded hosts.

Homes are sometimes invaded when large populations build up in
the yard.

56

Spider Mites

Petrobia latens is almost worldwide in distribution. It is known from
Europe, North Africa, Australia, and North America. This species was
not recorded from the United States until 1917, but it has since been
recognized as an important pest of agriculture in the southwestern and
western states. Collections also have been made in several eastern
states. Specimens studied are from England, as well as from Oregon,
Idaho, California, Arizona, New Mexico, Utah, Colorado, Kansas,
Oklahoma, Texas, North Carolina, and New Jersey.

Petrobia brevipes Reck and Bagdasarian

Petrobia brevipes Reck and Bagdasarian, 1949, Doklady Akad. Nauk
Armenia S.S.R., (10)4: 189. Types. Male and female, Erevan,
Armenia, on Kochia prostrata.

This species belongs to the latens group in possessing short dorsal
setae.

Petrobia erevanica Reck and Bagdasarian

Petrobia erevanica Reck and Bagdasarian, 1949, Doklady Akad. Nauk
Armenia S.S.R., (10)4: 190. Type. Females, Niuvad and Erevan,
Armenia, on Artemisia and other plants.

This species belongs to the latens group in possessing short dorsal
setae.

Petrobia zachvatkini (Reck and Bagdasarian), new combination

Tetrany china zachvatkini Reck and Bagdasarian, 1949, Doklady Akad.
Nauk Armenia S.S.R., (10)4: 191. Type. Females, Erevan, Armenia
on Salsola ericoides and Kochia prostrata.

This species belongs to the hard group in possessing long dorsal
setae set on tubercles.

GENUS SCHIZONOBIA WOMERSLEY

Schizonobia Womersley, 1940, Frans. Roy. Ent. Soc. S. Australia, 64(2):
251. I ype of genus: Schizonobia sycophanta Womersley;
basic.

mono-

57

Subfamily Bryobiinae Berlese

Fig. 39. Scni zonobia sycophanta : peritremes and tarsal
appendages (after rtomersley).

The genus Schizonobia, as described by ^omerslev, is closely allied
to Petrobia. It may be distinguished from P etrobia in that a single pair
of distallv directed tenent hairs are borne medially on the uncinate
empodium. The distal end of the peritreme, as figured by Womersley,
is also distinctive in that the branches originate together and fan out
to form a broadly rounded enlargement. The fore legs of the female are
not lengthened.

58

Spider Mites

Schizonobia sycophanta V/omersley

(Figure 39)

Schizonobia sycophanta Womersley, 1940, Trans. Roy. Ent. Soc. S.
Australia, 64(2): 251. Type: female, Hobart, Tasmania, on couch
grass; probably in the South Australian Museum.

This species is known only from the type female(s). We have not seen
this species.

GENUS APLONOBIA WOMERSLEY

Aplonobia Womersley, 1940, Trans. Roy. Soc. S. Australia, 64(2): 252.
Type of genus: ( Aplonobia oxalis Womersley) = A. histricina
(Berlese); monobasic.

The genus Aplonobia may be recognized by having the empodium
consisting of a pad bearing two rows of ventrally directed tenent hairs
or else a pair of tenent hairs, together with a rounded body bearing
only three pairs of dorsal propodosomals and with the inner sacrals
resembling dorsocentrals.

Aplonobia has been previously known from a single species in Aus¬
tralia. Five new species from the Pacific coast of the United States
are here referred to the genus.

The distal enlargement of the peritreme varies from being a complex
anastomosing chamber to having a simple enlargement in otherwise
similar species. There may be many fine dorsal striae, or the striae
may be comparatively few in number. The aedeagus forms a slender
stylet (fig. 40).

Key to the species of APLONOBIA

Females

1. Empodial pad twice as long as pad of true claw .... 2

1. Empodial pad not longer than pad of true claw .... 3

2. (1). Body with d orsal setae stout, as long as intervals between them,

and set on strong tubercles . histricina (p. 59)

2.(1). Body with dorsal setae very slender; much shorter than intervals
between them, and not set on tubercles . . . myops (p. 63)

59

Subfamily Hryobiinae Berlese

acharis

ame

anisa

Fig. 40. Aplonobia, aedeagi.

3.(i). Dorsal setae long and stout, arising from strong tubercles; en>
podial pad with rows of ventrally directed tenent hairs . . 4

3. (1). Dorsal setae slender or very short, not arising from strong tuber¬

cles; empodial pad with tenent hairs on either side united dis-
tallv . 5

4. (3). Hysterosoma with second and third pairs of dorsocentrals minute

. anisa (p. 64)

4. (3). Hysterosoma with second and third pairs of dorsocentrals as

long as first pair of dorsocentrals . deina (p. 67)

5. (3). Body with dorsal setae very short, not on tubercles; empodial

pad about as long as pad of true claw .... acharis (p. 69)

5.(3). Body with dorsal setae slender and tapering, set on small tuber¬
cles; empodial pad much shorter than pad of true claw .
. calame (p. 70)

Aplonobia histricina (Berlese), new combination
(Figures 41, 42)

T etranychopsis histricina Berlese, 1910, Redia. 6: 243. Types : females.
New South Wales, on fruit trees; in the Berlese collection at
Florence, Italy.

60

Spider Mites

P.60 Fig. 41. Aplonobia histricina : dorsal aspect of female, Australia,

Subfamily Hryobiinae Herlese

Fig. 42. Aplonobia histricina: A.) dorsocentral hysterosomal; B.) termination
of peritreme; C.) legs I and II of female; D.) tarsal appendages; E.) tarsus I of
female.

Aplonobia oxalis Womersley, 1940, Trans. Roy. Soc. S. \ustralia, 64(2):
253. Types : females. South Australia and New South Wales, on
Oxalis primarily; probably in the South Australian Museum. Aeu;
synonymy.

Aplonobia histricina may be readily recognized by the empodial pad
that is much longer than the pad of the true claw, together with the
stout setae on the dorsum of the body that arise from strong tubercles
and reach about as far as the distances between their bases. The end
of the peritreme bears a rounded enlargement that is composed primarily
of branches arising from the base of the expansion. There are numerous,
closely set striae on the dorsum of the body.

Aplonobia histricina is known only from Australia where it is found
commonly on Oxalis weeds in orchards. Womersley reports that fruit
trees may become infested, and that eggs are laid in clusters under

62

Spider Mites

bark und on twigs lying on the ground. Specimens studied by us, other
than Berlese’s types, were kindly forwarded by D. G. Swan.

63

Subfamily Bryobiinae fieri ese

Fig. 44. Aplonobia myops : peritremes and tarsus I of female, with
enlargement of tarsal appendages.

Aplonobia myops Pritchard and Baker, new species
(Figures 43, 44)

Females of Aplonobia myops may be readily recognized by having
the empodial pad much longer than the pad of the true claw, together
with having the dorsal setae of the body slender, much shorter than
the intervals between them, and not set on tubercles. The peritreme
is simple distally, and there are numerous, closely set striae on the
body.

Female. — Rostrum short, reaching middle of femur I. Palpus with
“claw” reaching end of fifth segment. Peritreme ending distally in a
simple enlargement. Legs with tactile setae similar, slender and finely
pubescent, tapering. Anterior legs about as long as body; tarsus I with
two pairs of dorsal and seven ventral, tactile setae proximal to the
duplex setae; and one mediolateral and one distoventral sensory setae
proximal to the duplex setae. Empodium somewhat tapering, twice as
long as pad of true claw, and with two rows of ventral ly directed tenent
hairs. Body with dorsal integument finely striate; dorsal setae all sim¬
ilar in size, very slender, finely pubescent, much shorter than intervals

64

Spider Mites

Fig. 45. Aplonobia anisa : dorsal aspect of female.

between their bases, and not set on tubercles. Length of body, 533 p ;
including rostrum, 666p.

Male. — Unknown.

Holotype. — Female, Holt, San Joaquin County, California, July 14,
1950 (W. W. Middlekauff) on asparagus; type no. 2076, in the U. S.
National Museum. Paratypes. — Fifteen females, Holt, California, July
14, 1950 (W. W. Middlekauff), on asparagus.

Dr. Middlekauff reported that this species was causing considerable
damage to a commercial field of asparagus.

Aplonobia anisa Pritchard and baker, new species
(Figures 45, 46)

Females of Aplonobia anisa may be readily differentiated from other
members of the genus by having the second and third pair of dorsocentral

65

Subfamily Hryobiinae Berlese

Fig. 46. Aplonobia tmisa: peritreme, tibia and tarsus I of female, with

enlargement of tarsal appendages.

hysterosomals minute. Setae on the anterior part of the dorsum of the
body are short and subspatulate, whereas the caudal setae are long
and slender.

Female. — Rostrum reaching end of genu I. Palpus with “claw” of
fourth segment approximate to end of segment five. Peritreme ending
in a distal, anastomosing, circular enlargement. Pegs with tactile setae
tapering, minutely pubescent, all of the same length; anterior legs
shorter than body. Empodia very slightly longer than pads of true claws
and each with two ventral rows of tenent hairs. Dorsum of body with
widely spaced striae. Propodosoma with dorsal setae stout, pubescent;
first pair slightly longer than second pair and first two pairs of setae
more acuminate than the subspatulate third ‘pair. Hvsterosoma with
second and third pair of dorsocentrals minute, the other setae anteriorly
being long and subspatulate but posteriorly stout and tapering. Length
of body, 353 g; including rostrum, 480 g .

Male. — Body with dorsal setae all slender and tapering, slightly
shorter than distances between their bases. Aedeagus with internal

66

Spicier Mites

Hg. 47. Aplonobia deina : dorsal aspect of female,
with enlargement of peritreme.

67

Subfamily Bryobiinae Berlese

Fig. 48. Aplonobia deina: above, tibia and tarsus I of female;
below, tibia and tarsus II of female.

portion very long and slender, the external portion consisting of a nearly
straight, slender and pointing sclerotization. Length of body, 335p ;
including rostrum, 406g.

Holotype. — Female, Bakersfield, California, August 11, 1949 (A. E.
Pritchard), on Artemisia-, type no. 2077, in the U. S. National Museum.
Paratypes. — Three males, 4 females, Bakersfield, California, August
11, 1949 (A. E. Pritchard), on Artemisia sp.

Aplonobia deina Pritchard and Baker, new species
(Figures 47, 48)

The females of Aplonobia deina closely resemble those of A. histricina,
the type of the genus, in that the dorsum of the body bears very long
setae that are set on strong tubercles. However, the empodium is not
more than approximately as long as the pad of the true claw. The dorsal
integument of the body bears numerous striae as in A. histricina.

Female. — Rostrum short, reaching middle of femur I. Palpus with
“claw” reaching end of fifth segment. Peritreme with the distal enlarge¬
ment a slender sac of branches originating together. Tegs with tactile
setae slender and strongly pubescent. I. eg I about as long as body;
tarsus I with two pairs of dorsal and three pairs of ventral tactile setae

68

Spider Mites

Fig* 49. Aplonobia acharis : dorsal aspect of female.

69

Subfamily Bryobiinae Berlese

Fig. 50. Aplonobia acharis : peritreme and tibia and tarsus I of female,

with enlargement of tarsal appendages.

proximal to the duplex setae; and one mediolateral and one distoventral
sensory setae proximal to the duplex setae. Empodium a short pad about
as long as the pad of the true claw, with two rows of ventrally directed
tenent hairs. Body with dorsal integument mostly with fine striae; dorsal
setae long, slender, tapering and set on strong tubercles, except for
the somewhat shorter marginal setae. Length of body, 533/i ; including
rostrum, 613 fx .

Male. — Unknown.

Holotype. — Female, Wenatchee, Washington, May 1952 (W. M. llants-
barger), on Balsamorrhiza sagittata; type no. 2078, in the U. S. National
Museum. Paratypes. — Five females, Wenatchee, Washington, May 1952
(W . M. llantsbarger), on Balsamorrhiza sagittata.

Aplonobia acharis Pritchard and Baker , new species
(Figures 49, 50)

The female of acharis may be differentiated from other species of
Aplonobia by having all the dorsal setae of the body minute, except

70

Spider Mites

for the slender anterior propodosomals. The integument, except for the
median area on the propodosoma, bears widely spaced striae. The em-
podium consists of a short pad on which each row of ventrally directed
tenent hairs are more or less united distally.

The male may be recognized by having the dorsal setae long and
slender but not as long as the intervals between their bases.

Female. — Rostrum reaching end of femur I. Palpus with “claw”
reaching end of fifth segment. Peritreme with distal enlargement con¬
sisting of two irregular branches. Legs with tactile setae strongly
tapering, finely pectinate. Leg I shorter than body; tarsus I with two
pairs of dorsal and seven ventral setae proximad of the duplex setae;
with a mediolateral, a distodorsal, and a distoventral setae proximal to
the duplex setae. Empodial pad about as long as pad of true claw, with
two rows of more or less distally united tenent hairs. Dorsum of body
with rather broadly spaced integumentary striae except for median
portion of propodosoma; dorsal setae slender, pubescent, fine except
for longer pair of anterior propodosomals. Length of body, 466 p ; in¬
cluding rostrum, 580//.

Male. — Similar to female except dorsal setae longer but not as long
as intervals between their bases. Aedeagus with external portion short,
straight, slender. Length of body, 400//; including rostrum, 486//.

Holotype. — Female, Tesla, California, October 20, 1949 (J. W.

MacSwain), on Hemizonia virgata; type no. 2079, in the U. S. National
Museum. P aratypes. — Six females, Livermore, California, October 15,
1948 (J. W. MacSwain), on Hemizonia sp.; 5 males, 24 females, Tesla,
California, October 20, 1949 (J. W. MacSwain), on H emizonia virgata;
8 males, 8 females, Tesla, California, July 27, 1950 (A. E. Pritchard),
on H emizonia virgata; 2 males, 2 females, Tesla, California, September
19, 1950 (A. E. Pritchard), on Hemizonia virgata.

Aplonobia calame Pritchard and Baker, new species
(Figures 51, 52)

The female of calame differs from other species of Aplonobia in
having the dorsal setae long and slender and set on small tubercles.
The empodium is distinctive in possessing a single, long pair of tenent
hairs.

The male is distinctive in having the dorsal setae long and slender,
fully as long as the intervals between them, and set on small tubercles.

Female. — Rostrum reuching end of femur I. Palpus with “claw”
reaching end of fifth segment. Peritreme with terminal enlargement

71

Subfamily liryobiiriat' Herlese

made up of three chambered branches. Legs with tactile setae narrowly
tapering, with long pectinations. Anterior legs about as long as body;
tarsus I with four dorsal and seven ventral tactile setae proximal to

72

Spider Mites

Fig. 52. Aplonobia calame : peritreme and tibia and tarsus of female,
with enlargement of tarsal appendages.

the duplex setae; with a mediolateral, dorsodistal, and distoventral
setae proximal to the duplex setae. Empodium a short pad bearing a
pair of tenent hairs that are nearly as long as the tenent hairs of the
true claws. Body with integumentary dorsum bearing rather widely
spaced striae except for pebbled area on propodosoma; dorsal setae
very slender, pubescent, about as long as intervals between their bases,
set on small tubercles. Length of body, 466 p; including rostrum, 566 p.

Male. — Similar to female except dorsal setae of body somewhat
longer. Aedeagus with external portion very long, slender, nearly
straight, and tapering. Length of body, 400p; including rostrum 466^i .

Ilolotype. — Female, Bakersfield, California, August 11, 1949 (A. E.
Pritchard), on a composite plant; type no. 2080, in the U. S. National
Museum. Paratypes. — Six males, 8 females, Bakersfield, California,
August 11, 1949 (A. E. Pritchard), on a composite plant.

73

Subfamily Bryobiinae Berlese

GENUS MESOTETRANYCHUS RECK

Mesotetranychus Heck, 1948, Trudy Zool. Inst. Akad. Nauk Gruz. S.S.R.,
8. lype of genus: Mesotetranychus vachushtii Heck; monobasic.

A description of the genus Mesotetranychus has not been seen by
us, nor a description of the type of the genus. Heck’s keys (1950, 1952a)
indicate that his genus is similar to Aplonobia and Monoceronychus.

Mesotetranychus vachushti i Reck

Mesotetranychus vachushtii Heck, 1948, Trudy. Zool. Inst. Akad. Nauk
Gruz. S.S. R., 8. Described from specimens from Georgia, S.S. H.
on Ephedra procera.

The de scription of this species has not been seen by us.

Mesotetranychus samgoriensis Reck

Mesotetranychus samgoriensis Reck, 1949, Soobsh. Akad. Nauk Gruz.
S.S.R., 10(6): 365. Described from females, Samgorien Desert,
Georgia, S.S. R., on Eryngium campestre.

Heck’s description and illustrations of Mesotetranychus samgoriensis
indicate that this species belongs to the genus Monoceronychus , as here
interpreted, inasmuch as the inner sacrals are placed laterally. However,
the body is rounded; and the closest relationship is probably with M.
corynetes , a species that may not properly belong in the genus Mono¬
ceronychus. A knowledge of the genital structures of the male of each
species may contribute to a better understanding of their generic place¬
ment.

Mesotetranychus samgoriensis is distinctive in having the dorsal
integument of the body mamillate. The dorsal setae are all short. The
empodium is longer than the proximal pad of each true claw. This species
is known only by the female from the Samgorien Desert of Georgia,

S.S.R.

74

Spider Mites

GENUS MONOCERONYCHUS McGREGOR

Monoceronychus McGregor, 1945, Proc. Ent. Soc. Wash., 47(4): 100;
McGregor, 1950, Anier. Midi. Nat., 44(2): 369. Type of genus:
Monoceronychus californicus McGregor; by original designation
and monobasic.

The genus Monoceronychus is very closely allied to Aplonobia. As
here recognized, the only constant difference observed between the two
genera consists in having the inner sacral setae more widely spaced
than the dorsocentral hysterosomals and placed more remotely from
them than the dorsocentrals are from each other.

Most of the species of Monoceronychus are readily differentiated
from Aplonobia by having the body very slender rather than rotund, the
propodosoma with a conspicuous, triangular projection mediocephalically
(not found elsewhere in the Tetranychidae), and the dorsal integument
of the body without striae in the area surrounding the third pair of dorso¬
central hysterosomals. Moreover, monocotyledonous plants (and gymno-
sperms) are the only known hosts of Monoceronychus, whereas Aplonobia
occurs on dicotyledonous plants.

One of the new species, Monoceronychus corynetes, swept from
grasses, is very intermediate between its assigned genus and Aplonobia.
It has a rather rounded body, no propodosomal projection, and possesses
dotted striae across the dorsocentral hysterosomal area. The antero¬
median placement of the inner sacral setae represents an extreme of
the Monoceronychus series.

In the only males known, Monoceronychus californicus, M. ae chmetes,
and M. linki, the distal portion of the aedeagus is very long and stylet¬
like, and ventrad of the aedeagus is a slightly wider, shorter, median
projection.

Fig. 53, Monoceronychus californicus : dorsal view of aedeagus.

75

Subfamily Hryobiinae Herlese

I L

I 1.

I 2.(1).

! 2.(1).

| 3.(1).
j 3.(1).

, 4.(3).

4. (3).

5. (4).

5. (4).

6. (4).
' 6.(4).

7. (3).

7.(3).

Key to the species of Monoceronychu s
Females

Propodosoma without an anteromedian projection ... 2

Propodosonm with an anteromedian projection . 3

Anterior legs longer than the body; iodiosoma rounded and with
spatulate dorsal setae . corynetes (p. 75)

Anterior legs shorter than the body; idiosoma slender and with
slender dorsal setae . mcgregori (p. 77)

Propodosoma with anteromedian projection much shorter than

rostrum . 4

Propodosoma with anteromedian projection as long as or longer
than rostrum . 7

Hysterosoma with caudal two pairs of setae very slender. . 5

Hysterosoma with caudal two pairs of setae obviously widened .
. 6

Anterior legs longer than body . machetes (p. 81)

Anterior legs much shorter than body . . . enoplus (p. 90)

Hysterosoma with caudal three pairs of setae broadly spatulate .

. californicus (p. 83)

Hysterosoma with caudal three pairs of setae lanceolate .
. aechmetes (p. 86)

Propodosomal projection covering only rostrum; hysterosoma
with caudal three pairs of setae slender, tapering, and set on

s-trong tubercles . scolus (p. 90)

Propodosomal projections covering entire gnathosoma; hystero¬
soma with caudal three pairs of setae differing in size and shape
and set on small tubercles . linki (p. 92)

Monoceronychus corynetes Pritchard and Baker, new species
(Figures 54, 55)

The female of corynetes may be differentiated from other members
of Monoceronychus, as well as Aplonobia , by having the body rounded,
the propodosomal projection absent, and the dorsal setae all short and
broadly spatulate. The anterior legs are much longer than the body.
The male is unknown.

76

Spider Mites

Fig. 54. Monoceronychus corynetes : dorsal aspect of female.

77

Subfamily Bryobiinae Berlese

Female. — Rostrum reaching just past the end of trochanter I. Stylo-
phore slender, broadly rounded anteriorly, Peritreme with distal enlarge¬
ment slender. Anterior leg one and one-half times as long as body;
dorsal setae on proximal segments slender and pubescent; tarsus I with
ten tactile and two sensory setae proximad of duplex setae. Empodium
somewhat longer than pad of true claw. Propodosoma without medio-
cephalic projection. Dorsum of body with crenulate and usually dotted
integumentary striae except for pebbled area on propodosoma; dorsal
setae all short and broadly spatulate. Length of body 413p ; including
rostrum 500 p.

Holotype. — Female, Tesla, California, September 21, 1951 (ft. C.
Bentinck), sweeping grass; type no. 2081 in the L. S. National Museum.
Paratype. — Female, Tesla, California, September 21, 1951 (ft. C.

Bentinck), sweeping grass.

Monoceronychus mcgregori Pritchard and Baker, new species

(Figures 56, 57)

The female of Monoceronychus mcgregori may be recognized by having
the propodosomal projection absent and the body slender. The anterior
legs are shorter than the body. The male is unknown.

78

Spider Mites

79

Subfamily Hryobiinae Herlese

/

Fig. 57. Monoceronychus mcgregori : above, tibia and tarsus I of
female; below, tibia and tarsus II of female.

Female. — Rostrum nearly reaching middle of femur I. Stylophore
slender, the sides angularly converging anteriorly and with a small
mediocephalic emargination. Peritreme with distal enlargement slender.

80

Spider Mites

Fig. 58. Monocerony chus machetes : dorsal aspect of female.

v\

81

Subfamily Bryobiinae Berlese

Fig. 59. Monocerony chus machetes : dorsal view of tarsus I of female.

Anterior leg distinctly shorter than body; dorsal setae on proximal seg¬
ments setiform; tarsus I with three tactile setae proximal to duplex
setae. Empodium distinctly longer than pad of true claw. Propodosoma
without anterior projections. Dorsum of propodosoma and most of opistho-
soma with nearly smooth integument, the metapodosomal dorsum with
rather widely spaced, solid striae. Dorsal propodosomals and dorsal
hysterosomals all minute and setiform except for somewhat longer outer
sacrais and clunals. Length of body 380 /j; including rostrum 420 ft.

Holotype. — Female, Miami Shores, Florida, May 5, 1952 (1). 0.

Kolfenbarger), on St. Augustine grass; type no. 2009 in the U. S. National
Museum. P aratypes. — Five females, Miami Shores, Florida, May 5, 1952
(D. O. Wolfenbarger), on St. Augustine grass.

This species is named in honor of E. A. McGregor who forwarded
to us the specimens for inclusion in this revision.

Monoceronychus machetes Pritchard and Baker, new species

(Figures 58 , 59)

The female of Monoceronychus machetes may be readily recognized
by having the anterior legs much longer than the body and the dorsal

82

Spider Mites

• • *' 4,- ;VV ■*».-

Fig. 60. Monocewnychus californicus : dorsal aspect of female, type.

setae of the body short and subspatulate except for slender setae caud-
ally. The male is unknown.

83

Subfamily Hryobiinae Herlese

Fig. 61. Monoceronychus californi cus'- above, tibia and tarsus I of
male; below, tibia and tarsus I of female.

Female. — Rostrum reaching to base of femur I. Stylophore slender,
rounded anteriorly. Propodosoma with anteromedian projection well
developed but shorter than rostrum, the anterior dorsal propodosomals
set on long projections. Leg I slightly longer than body; dorsal setae
on proximal segments slender and pubescent; tarsus I with four tactile
setae proximal to duplex setae. Empodium much longer than pad of true
claw. Body with broad dorsomedian area of propodosoma granulate, the
metapodosoma with rather widely spaced, solid, transverse striae.
Dorsal setae of body short and broadly lanceolate except for long and
slender outer sacrals and clunals. Length of body, 433 p; including
rostrum, 500 p.

Holotype. — Female, Jacumba, California, April 13, 1950 (A. E.

Pritchard), on juniper; type no. 2082 in the U. S. National Museum.

Monoceronychus cal ifornicus McGregor
(Figures 53, 60, 61, 62)

Monoceronychus califomicus McGregor, 1945, Proc. Ent. Soc. Wash.,
47(4): 100; McGregor, 1950, Amer. Midi. Nat., 44(2): 370. Types’-

84

Spider Mites

Pig. 62. Monoceronychus califomicus: dorsal aspect of male, type.

85

Subfamily Bryobiinae Berlese

63. Mono ceronychus aechmetes • dorsal aspect of female.

86

Spider Mites

/

Fig. 64. Monoceronychus aechmetes : tarsus I of female, with
enlargement of appendages.

males and females, Laguna Beach, California, on salt grass; in
the U. S. National Museum.

The female of Monoceronychus californicus may be readily recognized
by having broadly spatulate dorsal setae on a slender body that bears
a small anterior propodosomal projection. As here limited, this species
is known only from the coastal region of California, on salt grass.

In addition to the types from Laguna Beach, collections studied are
from Larkspur, California (R. E. Beer and A. E. Pritchard), on salt
grass; San Rafael, California (A. E. Pritchard), on salt grass; and
Clayton, California (J. W. MacSwain), on salt grass.

Monoceronychus aechmetes Pritchard and Baker, new species

(Figures 63, 64)

Monoceronychus aechmetes is very closely related to M. californicus,
and it may actually represent only a subspecies. Specimens of both
forms have been studied, and M. aechmetes differs consistently in having
the caudal setae of the body elongate — lanceolate rather than broadly
spatulate, and in being found in the interior valleys of California rather
than in the coastal area. McGregor (1950) noted the morphological dif¬
ferences.

Female. — Rostrum reaching proximal part of femur I. Stylophore
acuminate anteriorly and with a terminal angulation. Anterior legs much

87

Subfamily Bryobiinae Berlese

Fi

n*

65. Monoceronychus enoplus : dorsal aspect of female,

88

Spider Mites

Fig. 66. Mono ceronychus enoplus : dorsal and lateral
views of tarsus I of female.

shorter than body; dorsal, tactile setae of proximal segments slender;
tarsus I with five tactile and one sensory seta proximal to duplex setae.
Propodosoma with anteromedian projection slender, reaching as far as
ends of first propodosomal setae. Body with dorsum bearing transverse
striae across median portion, the propodosoma and opisthosoma with
strong areolets or globules; dorsal setae short and broadly spatulate
except for caudal three pairs of lanceolate setae. Length of body, 513 p;
including rostrum, 566p.

Male. — Similar to female. Shaft of aedeagus abruptly narrowed to
form a long and very slender terminal stylet. Length of body, 267 p ;
including rostrum, 300 p.

Holotype. — Female, Coalinga, California, May 10, 1952 (A. E.

Pritchard), on Agrostis sp.; type no. 2085 in the l . S. National Museum.
Paratypes. — One female, Sage, California, August 23, 1935, on Bermuda
grass; 1 male, 1 female, 1 nymph, Yokohl Valley, Tulare County, Cali¬
fornia, November 3, 1935 (E. A. McG regor), on salt grass; 1 female,
San Jacinto, California, May 26, 1951 (A. E. Pritchard), on salt grass;
1 female, Coalinga, California, May 10, 1952 (A. E. Pritchard), on
Agrostis sp.; 3 males, 13 females, Palm Canyon, California, August
19, 1934 (E. A. McGregor), on salt grass; and 2 nymphs, 3 larvae, Huron,
California, September 20, 1953 (A. E. Pritchard), on Bermuda grass.

89

Subfamily Rryobiinae Berlese

$>, f ^ Vi. ■

l*/’Sv v*

****#»• <9

•N.- ■ v O ^

Fig. 67. Monocerony chus scolus : dorsal aspect of female.

90

Spider Mites

Fig. 68. Monoceronychus scolus : tibia and tarsus I of female.

Monoceronychus enoplus Pritchard and Baker, new species
(Figures 65, 66)

The female of Monoceronychus enoplus may be readily recognized
by having the dorsal setae of the body short and lanceolate or narrowly
spatulate except for the slender two pairs of caudal setae.

Female. — Rostrum not reaching middle of femur I. Stylophore broadly
angulate anteriorly. Propodosoma with anteromedian projection present,
short and wide. Anterior leg much shorter than body; tactile setae on
dorsum of proximal segments setiform; tarsus I with six tactile and no
sensory setae proximal to duplex setae. Empodial pad similar in length
to pad of true claw. Dorsum of body with crenulate striations medially,
the propodosoma and opisthosoma largely pebbled. Length of body,
445 p; including rostrum, 533 ft.

Holotype. — Female, Hemet, California, May 26, 1951 (A. E.

Pritchard), on grass; type no. 2084 in tHe U. S. National Museum.
Paratype. — One female, Hemet, California, May 26, 1951 (A. E.

Pritchard), on grass.

A protonymph, Tesla, California, October 4, 1951 (J. E. Gillaspy),
on grass, is also regarded as representing this species. The nymph
resembles the adult except that the dorsal setae are very small and
slender except for longer and more lanceolate anterior propodosomals
and inner sacrals.

Monoceronychus scolus Pritchard and Baker, new species
(Figures 67, 68)

Females of Monoceronychus scolus are distinctive in having all
of the lateral setae on the body long and slender, set on strong tuber¬
cles. The anteromedian projection of the propodosoma is very long,
covering the rostrum. The male is unknown.

91

Subfamily Bryobiinae Berlese

Fig. 69. Mono cerony chus linki : dorsal aspect of female.

92

Spider Mites

Fig. 70. Mono cerony chus linki: above, tibia and tarsus I of male;
below, tibia and tarsus I of female.

Female. — Rostrum reaching proximal third of femur I. Stylophore
broadly angulate anteriorly. Propodosoma with median projection very
long, covering rostrum. Anterior legs much shorter than body; dorsal
setae on proximal segments very long and slender, pubescent; tarsus
I with five tactile setae and a proximolateral sensory seta proximal
to the duplex setae. Empcdium longer than pad of true claws. Body
with dorsal integument transversely striate medially and with clusters
of globules over must of propodosoma and opisthosoma; dorsal setae
all lateral, slender, set on obvious tubercles except for the three pairs
of short and broadly lanceolate dorsocentral hysterosomals. Length
of body, 533 p .

Iiolotype. — Female, Hemet, California, May 26, 1951 (A. E.
Pritchard), on grass; type no. 2083 in the U. S. National Muse¬
um. Paratypes. — Two females, Hemet, California, May 26, 1951 (A. E.
Pritchard), on grass.

Five deutonymphs, Durham, North Carolina, June 18, 1953 (A. E.
Pritchard), on Bermuda grass, appear to represent Mono cerony chus
scolus. The nymphs differ from the females mainly in having smaller
dorsocentral hysterosomals and a smaller anteromedian projection of
the propodosoma.

Monoceronychus linki Pritchard and Baker , new species
(Figures 69, 70, 71, 72)

Adults of Mono cerony chus linki may be recognized by having three
anterior projections of the propodosoma very strongly developed and
covering the rostrum and palpi.

93

Subfamily Bryobiinae Berlese

Fig. 71. Monocerony chus linki : dorsal aspect of male.

94

Spider Mites

B.) propodosomal projections of male; C.) tarsus II of female with enlargement
of appendages.

Female. — Rostrum not reaching end of trochanter I. Stylophore slen¬
der, slightly emarginate mediodistally. Leg I about as long as body;
dorsal setae on proximal segments lanceolate; tarsus 1 with five tactile
setae proximal to duplex setae. Empodium about as long as pad of true
claw. Propodosoma anteriorly with mediolateral angulations and with
three strong, medially widened projections covering gnathosoma. Dorsal
integument punctate, the metapodosoma with transverse striae. Dorsal
setae of body very short and mostly lanceolate, the clunals being long
and slender. Length of body 725 p; greatest width of body 292 p.

Male. — Similar'to female except legs I much longer than body; tarsus
I with ten tactile setae proximad of duplex setae; and clunal setae
shorter and more lanceolate. Aedeagus abruptly constricted to form a
long, stylet-like distal portion. Length of body 711 p; greatest width
of body, 285 p.

Holotype. — Female, Miami, Florida, April 15, 1953 (0. D. Link), on
Mariscus amcinensis ; type no. 2181 in the U. S. National Museum. Para-
types. — Five males, 4 females, 1 nymph, Miami, Florida, April 15, 1953
(0. D. Link), on saw grass.

95

Subfamily Hryobiinae lierlcse

lhis species is named in honor of 0. 1). Link who collected this
and many other interesting tetranychoids in Florida.

2

Subfamily

TETRANYCHINAE

Berlese

Tetranychini Berlese, 1913, Acaroth. Ital., p. 17

Tetranychinae Reck, 1950, Trudy Inst. Zool. Akad. Nauk Gruz. S.S.R.,
9:123.

Tetranychidae Reck, 1952, Soobsh. Akad. Nauk Gruz. S.S.R., 13(7): 423.

The subfamily Tetranychinae is distinctive in having only two pairs
of anal setae in the female and four pairs of genito-anal setae in the
male. The true claw is reduced to a very small pad bearing a long pair
of tenent hairs. The empodium bears no tenent hairs, although paired
hairs are often present proximoventrally.

The placement of the duplex setae varies considerably, and the
proximal (tactile) member is nearly always more strongly developed
than in the Bryobiinae. There are three pairs of dorsal propodosomals
and only ten pairs of dorsal hysterosomals, the dorsosublaterals being
absent.

Key to the tribes of Tetranychinae

1. Tarsus I dorsally with two pairs of duplex setae, the proximal
member of each pair shorter than the distal member ... 2

1. Tarsus I dorsally with at most a single pair of usually loosely
associated duplex setae, the proximal member usually as long as or
longer than the distal member, or else duplex setae absent;

96

97

Subfamily Tetrarxychinae B erlese

emporium very small or absent . . EuRYTETRANYCHINl (p.100)

Hysterosoma with sacral setae all marginal; tarsus II with distal
member of duplex setae a short sensory peg; propodosoma reti¬
culate dorsally . TENUIPALPOIDINl (p. 97)

Hysterosoma with inner sacrals mediodorsal; tarsus II with distal
member of duplex setae long and tapering; propodosoma without
reticulations . TetrANYCHINI (p.124)

TENUIPALPOIDINl PRITCHARD AND BAKER, new tribe

The tribe Tenuipalpoidini is a rather anomalous or, perhaps, somewhat
primitive member of the subjamily Tetranychinae. The strongly reduced
pad of the true claw, as well as the presence of only two pairs of anal
setae in the female and four pairs of genito-anal setae in the male,
indicates a subfamilial relationship with the I etranychinae. However,
the character and placement of the setae on tarsus I, the complex distal
enlargement of the peritreme, the integumentary sculpture, and the
lateral position of the inner sacrals are all characteristic of the
Bryobiinae.

TENUIPALPOIDES RECK AND BAGDASARIAN

Tenuipalpoides Reck and Bagdasarian, 1948, Doklady Akad. Nauk
Armenia S.S.R., (9): 4: 183-186.

Type of genus. — Tenuipalpoides zizyphus Reck and Bagdasarian,
monobasic and by original designation.

The genus Tenuipalpoides may be recognized by having the peritreme
hooked or with an irregularly pectinate enlargement distally, tarus I with
two pairs of well-developed duplex setae placed on the dorsodistal
declivity, tarsus II with the distal member of the duplex setae short and
peglike, and the empodium simple, short and uncinate.

Tenuipalpoides zizyphus Reck and Bagdasarian

Tenuipalpoides zizyphus Reck and Bagdasarian, 1948, Doklady Akad.
Nauk Armenia S.S.R., (9) 4: 183-186. Described from female,
Erevan, Armenia on Zizyphus vulgaris (Lam.).

Spider Mites

98

99

Subfamily T etrany chinae fieri ese

Tenuipalpoides zizyphus may be recognized bv having the distal
ends of the peritremes hooked rather than with irregular pectinate
branches. The dorsal body setae as illustrated appear to be shorter than
in 7 . dorychaeta from locust, and tibia 1 has two broadly lanceolate setae
instead of a single one found in I\ dorychaeta.

Tenuipalpoides dorychaeta Pritchard and Baker, new species

(Figures 73, 74)

The peritreme development separates this species from T. zizyphus.

Female. — Rostrum broadly obtuse anteriorly. Peritreme with distal
end broadly enlarged because of irregularly pectinate branches. Tarsus
1 with an inner, tactile seta and an outer sensory seta proximal to duplex

Fig. 74. Tenuipalpoides dorychaeta: A.) appendages of female tarsus IV;
B.) peritreme; C.) tarsus I of female; D.) duplex setae of tarsus II of female.

100

Spicier Mites

setae. Propodosoma with dorsum reticulate, the integument bearing
fine dashes; hysterosomal dorsum with widely-spaced, irregular mostly
transverse wrinkles and with dashed integumentary striae. Idiosoma
with dorsal setae all long, mostly longer than intervals between them,
and broadly lanceolate, the expansion beyond the median, sclerotized,
setiform skeleton being thinner and serrate. Length of body, 400 p ;
including rostrum, 566 p; greatest width of body 330 p .

Male. — Similar to female. Tarsus 1 with two sensory setae proximad
of duplex setae. Aedeagus with distal end turned dorsad, sigmoid and
tapering. Length of body, 400 p; including rostrum 533 p.

Holotype. — Female, Natchez, Louisiana, August 22, 1953 (H. B.
Boudreaux), on black locust; type no. 2175, in the U. S. National Mu¬
seum. Paratypes. — Two males, five females, six nymphs, Natchez,
Louisiana, August 22, 1953 (H. B. Boudreaux), on black locust; one
male, 4 females, 2 nymphs, Durham, North Carolina, June 11, 1953
(A. E. Pritchard and H. B. Boudreaux), on honey locust; one male, four
females, Logan, Utah (G. F. Knowlton and E. M. Kardo), on black locust;
and one female, (Utah (G. F. Knowlton and Shi Chun Via), on unknown host.

In life the mites are brilliant red with snow-white setae. They are
rather inactive and are found on the bark of honey locust and black
locust.

TRIBE EURYTETRANYCHINI RECK

Eurytetranychinae Reck, 1950, Trudy Inst. Akad. Nauk Gruz. S.S. R.,
9: 123; Reck, 1952, Izd. Akad. Nauk S.S. R., 1952: 25; Reck,
1952, Soobsh. Akad. Nauk Gruz. S.S. R., 13(7): 423.

Members of the tribe Eurytetranychini are quite distinctive in that
tarsi I and II both lack the duplex setae that are otherwise so character¬
istic of the family T etranychidae. Tarsus I and tarsus II each may bear
dorsally a single pair of setae that appears to be homologous with the
duplex setae, but the proximal (tactile) member of the pair is more
strongly developed than the distal (sensory) member, and their alveoli
are adjacent but not coalescent. Tarsus I bears lateroventrally a pair
of setae that resemble the second pair of duplexes. The body is rotund,
and the legs are long and slender. There are ten pairs of dorsal hyster-
osomals and two pairs of para-anals. The dorsal integument of the body
is striate. The termination of the peritreme is a simple distal bulb or
hook.

Eurytetranychine mites feed primarily on the dorsal surface of leaves.

101

Subfamily I etranychinae lierlese

Key to the genera of Eury tetranychini

1.

1.

Empodial claw present, small and hooked .

. Eurytetranychus (p.101)

Empodium rudimentary and rounded, appearing absent ....
. Eutetranychus (p. Ill)

GENUS EURYTETRANYCHUS OUDEMANS

Eury te tr any chus Oudemans, 1931, hint. Her., 8(178): 224, Geijskes,
1939, Meded. Landbouwh. Wageningen, 42(4): 30. 7 ype of genus:
Uetranychus latus, Oudemans, not Canestrini and Fanzago) =
Eury tetrany chus buxi (Carman); monobasic and by original desig¬
nation.

Simplinychus McGregor, 1950, Amer. Midi. Nat., 44(2): 274. Type of
genus : A eotetranychus buxi Garman; monobasic and by original
designation. A eiv synonymy.

Eurytetranychoid.es Reck, 1950, Trudy Inst. Akad. Nauk Gruz. S.S. R.,
9: 127. Type of genus: Eurytetranychus thujae Reck; monobasic
and by original designation. A ew synonymy.

1 he empodium of Eury tetrany chus consists of a rudimentary, uncinate
projection. I he only other genus of tetranychids having a similar em¬
podium is Tenuipalpoides , a dissimilar genus having the sacral setae all
strongly widened and marginal, and having well-developed duplex setae.
In Eurytetranychus the inner sacrals resemble dorsocentral hysterosom-
als, and duplex setae, as such, are absent.

Eurytetranychoides was differentiated from Eurytetranychus because
the species on which the fomier name was based has a single pair of
postanals, whereas two pairs of postanals are apparent in Eurytetrany¬
chus. A single pair of postanals is present in E. admes, a species
closely allied to the type of Eurytetranychoides. However, the first
pair of para-anals is present in admes, and it is probable that they were
overlooked by Reck. A difference in the placement of the anterior para-
anals is insufficient for generic recognition.

Zacher (1933) considered both P aratetranychus nuptialis Zacher
and P. brevipilosus Zacher to belong to the genus Eury tetranychus. The
original generic reference of ( P aratetranychus ) - Oligonychus for these
species was correct. Ugarov and Nikolskii (1937) described Eury tetrany-
chus stenoperitrematus, a species that is also properly referable to the
genus (P aratetranychus) - Oligonychus (Baker and Pritchard, 1953).

102

Spider Mites

Fig. 75. Eurytetranychus buxi: dorsal aspect of female, Florida.

Key to the species of EURYTETRANYCHUS *

1. Dorsal setae nearly as long as intervals between them; sensory

setae absent on tibia III an d IV . buxi (p.103)

Dorsal setae less than one-fourth as long as intervals between
them; proximal sensory seta present on tibia III and also tibia

IV . admes (p.110)

*We have not seen the descriptions of E. thujae and E. recki.

1.

103

Subfamily Tetranychinae Herlese

Fig. 76. Eurytetranychus buxi: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus 1 of male; D.) tibia and tarsus
II of male.

Eurytetranychus buxi (Garman), new combination
(Figures 75, 76, 77, 78)

Tetranychus latus, Berlese (not Canestrini, 1876), 1889, Acari Myr.
Scorp. Frostigmata, 46: 7. Misidentification.

104

Spider Mites

105

Subfamily T etruny chinae Herlese

Fig. 78. Eurytetrcinychus buxi : aedeagus and appendages of
tarsus I of female (left) and male (right).

Eurytetranychus latus, Oudemans, 1931, Ent. Ber., 8(178): 224: Geijskes,
1939, Meded. Landbouwh. Nageningen, 44(4): 30; Reck, 1948,
Trudy Zool. Inst. Akad. Nauk Gruz. S.S.R., 9(4). Misidentifi-
cation.

Eutetranychus latus, Ewing, 1932, Proc. Ent. Soc. ^ash., 34: 14. Mis -
identification.

A eotetrany chus buxi Garman, in Ries, 1935, Jour. Econ. Ent., 28: 57;
Garman, 1940, Bui. Conn. Agr. Expt. Sta., 431: 73. Types: males
and females, Michigan, on boxwood; probably in the collection
of the Connecticut Agricultural Experiment Station.

Simplinychus buxi, McGregor, 1950, Amer. Midi. Nat., 44(2): 274.

Canestrini and Fanzago (1876, 1878) originally stated that Tetrany-
cfius latus occurs on conifers. The illustration in the latter article,
inordinately diagnostic with regard to tarsal appendages for that period

106

Spider Mites

I'ig. 7l). hurytetrunychus admes: dorsal aspect of female

107

Su

bfamily Tetranychinae fierlese

Fig. 80. Eurytetranychus admes : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of male.

108

Spider Mites

Fig. 81. Eurytetranycnus admes : dorsal aspect of male,
with enlargement of aedeagus.

of research, clearly shows two well-developed true claws. This indi¬
cates that 7. latus cannot be a tetranychid. Moreover, the very strongly
developed palpi and the very small rostrum figured are not in keeping
with the tetranychid figures of these Italian workers. The shape of the
specimen figured and the comparative development of the dorsal body
setae are similar to those of certain species of the Eurytetranychini,
but this is not sufficient for recognition of T. latus as a tetranychid.

We believe, therefore, that Berlese (1889) erred in his identification

109

Subfamily T etranychinae flerlese

Fig. 82. Eurytetranyc/ius admes: tarsus I of female with
enlargements of appendages.

of T etranychus latus Canestrini. He apparently illustrated the boxwood
spider mite as this species, even though McGregor (1950) considered
Berlese’s figure of the foreshortened fifth palpal segment, the tibio-
tarsal proportions, and the length of the leg vestiture to be an indication
that a related species was under consideration.

Other workers have based their identifications of latus on Berlese’s
redescription and figures, but they have differed as to whether the name
should apply to mites here considered under the name Eury tetranychus
buxi or else Eutetranychus banksi.

Eurytetranyc/ius buxi is credited to Garnian alone (and not Carman
and Ries), because the article by Ries (1935) indicates that Garman
was responsible for the original description. 1 h is species may be readily
recognized by possessing, in addition to the generic characters, slender
dorsal setae of which many are nearly as long as the intervals between
their bases.

This spider mite occurs primarily on the European boxwood, Suxus
semp ervirens, and it is often a serious pest of this ornamental plant.
The Japanese boxwood, Buxus microphylla , is rarely infested.

In addition to the record of Berlese (1889) of collections from Italy,
E ury te trany c bus buxi is known to be widespread in the l nited States.
Garman (1935,1940) described specimens from Michigan and Connecti¬
cut, and Ewing (1932) reported collections from Virginia and Ohio.

110

Spider Mites

McGregor (1950) reported collections from California, Georgia, Michigan,
Oregon, and Virginia. Specimens studied by us are mostly from Berkeley,
San Rafael, and Niles, California (A. E. Pritchard), on Buxus semper-
virens; Medford, Oregon (L. G. Gentner), on boxwood; and Durham,
North Carolina (A. E. Pritchard), on Buxus spp.

Eurytetranychus admes Pritchard and Baker , new species

(Figures 79, 80, 81, 82)

Eurytetranychus admes differs from E. buxi in that the dorsal setae
of the body are much shorter than in E. buxi, and tibiae III and IV each
possesses a proximal sensory seta that is absent in that species. More¬
over, it occurs only on cupressaceous conifers.

Female. — Stylophore slightly emarginate distally. Peritreme with
distal end hooked. Palpus with terminal sensillum slender. Anterior
legs about as long as body; tibia I with nine tactile and one sensory
setae; tarsus I without paired setae resembling duplex setae; tibia II
with eight tactile and one sensory setae; tarsus II without paired setae
resembling duplex setae; tibiae III and IV each with a dorsomedian
sensory seta in addition to the tactile setae. Idiosoma with dotted
dorsal striae; dorsal setae slender, tapering, pubescent, greatly shorter
than intervals between them. Length of body, 466 p ; including rostrum,

606 p.

Male. — Similar to female. Tibia I with eight tactile and five sensory
setae. Aedeagus distally turned dorsad at right angle and tapering to
a slightly sigmoid apex. Length of body, 320 p; including rostrum, 413/z.

llolotype. — Female, Camp Nelson, California, September 7, 1947
(E. W. Baker), on incense cedar; type no. 2119 in the U. S. National
Museum. Paratypes. — Four males, 19 females, Camp Nelson, California,
September 7, 1947 (E. W. Baker), on incense cedar; 2 females, Keen
Camp, California, May 26, 1951 (A. E. Pritchard), on juniper; 1 male,
PI acerville, California, July 19, 1950 (A. E. Pritchard), on incense
cedar; and 6 females, Utah (G. F. Knowlton), on juniper.

Eurytetranychus thujae Reck

Eurytetranychus thujae Reck, 1947, Soobsh. Akad. Nauk Gruz. S.S.R.,
8(7). Described from female, Georgia, S.S.R., on {Biota) - Thuja
orientalis.

Eurytetranychoid.es thujae, Reck, 1950, Trudy Inst. Zool. Akad. Nauk
Gruz., 9: 127.

Ill

Su bfam ily I e trany chinae lierlese

Heck, s 1950 description of this species indicates that it is closely
allied to Eurytetranychus admes. lhe original description lias not been
seen.

Eurytetranychus recki Bagdall

Euryt etranychus recki Bagdall, 1948, Dokl. Akad. Nauk Armenia S.S. R.,
9(3). Described from specimens from Armenia, on Astragalus
caucasicus or Medicago spp., or both,
oe have not seen the article in which this species was described.

GENUS EUTETRANYCHUS BANKS

A eotetranychus ( Eutetranychus ) Banks, 1917, Ent. News, 28: 197. Type
of subgenus : 7 etranychus banksi McGregor, by subsequent desig¬
nation of McGregor, 1950.

Eutetranychus , McGregor, 1950, Amer. Midi. Nat., 44(2): 267.

Anychus McGregor, 1919, Proc. U, S. Natl. Mus., 56: 644; Sayed, 1942,
Bui. Soc. F'ouad ler Ent., 26: 125; Sayed, 1946, Bui. Soc. Fouad
ler Ent., 30: 143. Type of genus: T etranychus banksi McGregor;
by original designation.

The genus Eutetranychus is distinctive in that the empodium is
rudimentary and consists only of a rounded knob. Tarsus I bears on the
dorsum a pair of associated setae that are probably homologous with
one pair of the duplex setae. However, the alveoli are not coalesced,
and the proximal, tactile member is longer than the more distal, sensory
member.

Key to the species of EUTETRANYCHUS

1. Body with dorsal setae set on strong tubercles; dorsocentral
hysterosomals as long as dorsolateral hysterosomals . . 2

1. Body with dorsal seta not set on tubercles; dorsocentral hyster¬
osomals obviously shorter than dorsolateral hysterosomals .
. banksi (p.X 15)

112

Spider Mites

Dorsocentral hysterosomals long and tapering; third dorsal propo-
dosomal, humeral, outer sacral and clunals all slender and blunt

. spinosus (p.113)

Dorsocentral hysterosomals long and blunt; third dorsal propo-

dosomal, humeral, outer sacral and clunals all short and spatu-

late . schultzi (p. 1 IS)

Fig. 83. Eutetranychus spinosus: dorsal aspect of female, Maryland.

113

Subfamily T etranychinae Berlese

Fig. 84. Eutetranychus spinosus : above, tibia and tarsus 1 of female, with
ventral enlargement of distal end of tarsus: below, tibia and tarsus II of female.

Eutetranychus spinosus [Banks)

(Figures 83, 84, 88, 86)

T etranychopsis spinosa Banks, 1909, Proc. Ent. Soc. Wash., 11: 134.
Type', female, Guelph, Ontario, Canada, on basswood; in the
Museum of Comparative Zoology, Cambridge, Massachusetts.

A eotetranychus ( Eutetranychus ) spinosa. Banks, 1917, Ent. News,
28: 197.

Eutetranychus spinosa, McGregor, 1950, Amer. Midi. Nat., 44(2): 267.

The female of Eutetranychus spinosus may be readily differentiated
from other species in the genus by having the dorsocentral hysterosomals
very long and tapering, together with having the third propodosomal,
humeral, and outer sacrals short, slender, and sometimes blunt. The
dorsal setae of the body are set on strong tubercles. The dorsolateral
hysterosomals are similar to the dorsocentral hysterosomals; but the
outer sacrals are very short and slender, and the clunals are somewhat
shorter than the inner sacrals.

The male, previously unknown, resembles the female. The aedeagus
has the distal half of the external portion bent sharply dorsad, with the

114

Spider Mites

/

1'ig. 05. Eutetranychus spinosus : above, tibia and tarsus I
of male; below, tibia and tarsus II of male.

115

Subfamily T etrany chinae Rerlese

Fig. 86. Eutetranychus spinosus : aedeagus.

distal end curved somewhat caudad, and narrowing to a blunt tip.

In addition to the type female from Canada, on basswood, one female
was examined from Cabin John, Maryland, September 17, 1944 (E.
Baker), on grass; and a series was studied from Ithaca, New York
(J. G. Matthysse), on linden.

Eutetranychus schultzi ( Blanchard ), new combination

(Figures 87, 88, 89)

Anychus schultzi Blanchard, 1940, Rev. Fac. Agron. La Plata, (3)2: 24
(1939). Types: females, Tucuman, Argentina, on Ricinus com¬
munis; of unknown disposition.

Eutetranychus schultzi is closely allied to E. spinosus. The female
has long, slender, and nearly parallel-sided dorsocentral hysterosomals
and they are blunt distally. They are also set on strong tubercles.
However, the third dorsal propodosomals, the humeral, the outer pair
of sacrals, and the clunals are all very short and broadly spatulate.
The anterior pair of dorsal propodosomals are slender but shorter, as
in E. spinosus. The male is unknown.

Our recognition of this species is based on specimens from Buenos
Aires, Argentina, on Ricinus sp.; kindly forwarded by A. Ibarra Grasso.

Eutetranychus banks i (McGregor)

(Figures 90, 91, 92)

T etrany ch us banksi McGregor, 1914, Ann. Ent. Soc. Amer., 7(4): 358.
Types : females, Orlando, Florida, on castor bean and velvet
bean; in the U. S. National Museum.

l\eotetranychus ( Eutetranychus ) banksi, Banks, 1917, Ent. News, 28:
177.

Anvchus banksi, McGregor, 1919, Proc. L. S. Natl. Mus., 56(2303): 644.
Eutetranychus banksi, McGregor, 1950, Amer. Midi. Nat., 44(2): 268;
Muma, Holtzberg, and Pratt, 1953, Fla. Ent., 36(4): 141.

116

Spider Mites

Fig. 87. Eutetranychus schultzi: dorsal aspect of female, Argentina.

Tetranychus rusti McGregor, 1917, Proc. U. S. Natl. Mus., 51(2677):
582. Types: males and females, Mira Flores Station, Dept. Piura,
llaciendo “San Jacinto,” Peru; in the G. S. National Museum.

New synonymy.

117

Subfamily 7 etrany chinae Berlese

Fig. 88. Eutetranychus scnultzi : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; B.) tibia and tarsus II

of male.

118

Spider Mites

Fig. 89. Eutetrany chus schultzi: aedeagus.

Anychus rusti, McGregor, 1919, Proc. II. S. Natl. Mus., 56(2303): 645.
Eutetrany chus rusti, M cGregor, 1950, Amer. Midi. Nat., 44: 669.

Anychus ?latus. Hirst, 1923, Proc. Zool. Soc. Lond., 1923 : 991. Mis-
identification.

Anychus latus, Sayed, 1942, Bui. Soc. Fouad ler Ent., 26: 125. Mis-
identification.

Anychus africanus Tucker, 1926, Union S. Afr. Dept. Agr., Div. Ent.
Mem., 5: 5. Types : males and females, Durban, Natal, on oranges
and lemons, and Plumeria (Frangipani); of unknown disposition.

New synonymy.

Anychus clarhi McGregor, 1935, Proc. Ent. Soc. Wash., 37: 161. Types:
males and females, Weslaco, Texas, on citrus; in the U. S.
National Museum.

Eutetranychus clarki, McGregor, 1950, Amer. Midi. Nat., 44: 270.

Anychus orientalis (Zacher) Klein, 1936, Bui. Agric. Res. Sta. Rehovoth,
21: 3; Sayed, 1946, Bui. Soc. Ent. Fouad ler Ent., 30: 143. (This
species appears to be based on a manuscript name of Zacher.)
Anychus verganii Blanchard, 1940, Rev. Fac. Agron. La Plata, (3)2: 24
(1939). Types : females, Bella Vista, Corrientes, Argentina, on
citrus; of unknown disposition. Neiv synonymy.

Anychus ricini Rahman and Sapra, 1940, Proc. Ind. Acad. Sci., ll(sect.
B): 194. Types: males and females, Lyallpur, India, on castor
bean, almond, Cassia fistula , Ziziphus jujuba, and citrus; of
unknown disposition. New synonymy.

Eutetranychus mexicanus McGregor, 1950, Amer. Midi. Nat., 44: 27.

119

Subfamily T etranychinae Herlese

Fig. 90. Eutetranychus banksi: dorsal aspect of female, Florida, croton.

Types : female and two nymphs, Guadalajara, Mexico, on sapota:
in the U. S. National Museum.

Our studies indicate that Eutetranychus banksi is a polytypic spe¬
cies. It appears that there are several different morphological forms
as far as the development of dorsal body setae are concerned, and that
intercontinental introduction of these forms on citrus and certain orna¬
mental plants has created widespread opportunity for interbreeding and
and morphological intermediates.

The dorsal setae of the female body are all short and spatulate in
the tvpe series of banksi (Florida, citrus), with certain of the laterally
situated setae somewhat longer than the more mediodorsally located
setae. Specimens representing verganii (Argentina, citrus), are similar

120

Spider Mites

D

Fig. 91. Eutetranychus banksi: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

121

Subfamily l etrany chinae Berlese

Fig. 92. Eut etrany cnus banksi: dorsal aspect of male,
with enlargement of aedeagus.

122

Spider Mites

except that there is more disparity between the length of the dorsolateral
setae and the dorsomedian setae.

In correlation with an increased length of the dorsolateral setae
of the body, there is a tendency for these setae to be less spatulate
or merely slender and rather blunt, as in the types of rusti (Peru, papa¬
ya). Such variations are found on many individual specimens and within
individual series studied from Florida, Texas, Mexico, and Argentina.
The forms having the lateral setae slender and parallel-sided resemble
the types of clarki (Texas, citrus) as figured and illustrated by McGregor
(1935). However, the type series of clarki also consists of females
that have the lateral setae of the body slender and subspatulate.

The dorsocentral hysterosomals are short and spatulate in females
having subspatulate lateral setae. However, those specimens having
slender lateral setae sometimes have slender dorsocentral hysterosomals
(particularly in males and nymphs). The dorsocentral hysterosomals
tend to be longer and more or less slender in the types of mexicanus
(southern Mexico, citrus) and certain specimens from Florida, Texas,
Mexico, and Argentina.

We are, therefore, unable to differentiate between banksi, verganii,
clarki, rusti, and mexicanus, inasmuch as complete intergrades are
found between the length and shape of the dorsal setae of the female
body. No other differences such as the number and arrangement of dorsal
setae referred to by McGregor (1919, 1950) have been verified. Muma,
Holtzberg, and Pratt (1953) were also unable to differentiate Eutetrany-
chus banksi, E. clarki, and E. mexicanus.

Still another form has been noted in specimens from .Texas citrus
wherein the females possess lateral setae on the body that are long,
slender, and tapering. Specimens with dorsolateral body setae that are
tapering have been observed also from Mexico and Florida. Again, there
appears to be no sharp distinction from similar setae that are slender
but comparatively blunt.

Hirst (1923) identified as ?latus (Canestrini) Berlese a spider mite
found on citrus and other hosts in the Sudan. Hirst’s description indi¬
cates a species belonging to the genus Eutetranychus as defined by
us. Sayed (1942) accepted this identification of latus as being applic¬
able to a species from Fgypt having relatively slender and subspatulate
setae on the dorsum of the female.

Later Sayed (1946) identified as orientalis Zacher (apparently a
manuscript name) females with shorter and more spatulate dorsocentral
hysterosomals. Sayed further remarked that the status of latus would
remain in doubt until Berlese’s specimens were examined.. However,
Sayed (1946) simultaneously recognized as latus, a similar form in

123

Subfamily 1 etrany chinae lierlese

which the Literal setae of the body are slender and tapering, and the
dorsocen tral hysterosonials were also figured as slender and tapering.

Specimens studied by us from Israel, on citrus, show some of the
variations found in specimens from the New World. The lateral setae
of the female are slender and subspatulate, or else slender and tapei^
ing; and the dorsocentral hysterosonials are short and sputulate, or
else slender. Thus, they illustrate intermediates between the dorso¬
lateral setae of the two forms illustrated by Sayed (1946), but the tuper-
ing dorsocentral hysterosonials of the female of latus, as determined by
Saved, are different (see pantopus).

1 he descriptions of africanus (South Africa, citrus) and ricinus (India)
indicate that type specimens resemble those determined by Sayed (1946)
as orientalis.

A sensory seta is present at the proximal end of tibia III in the
specimens from Israel. This sensory seta is absent in specimens studied
from the Americas, and the significance of this sensillum is not known.
No geographical isolation is particularly evident with citrus pests that
appear to have been distributed throughout the world.

No differences have been observed among the aedeagi of males asso¬
ciated with females representing the various developments of dorsal
setae. The aedeagus is simple, abruptly turned dorsad near the distal
end. The development of the dorsal setae of the male body varies, but
not as strongly as in the females with regard to differential length of
the dorsocentral hysterosonials and the lateral setae. The same is true
for the nymphs.

In summary, this species complex is known from Texas and Florida
in the United States; Mexico, Argentina, and Peru in Central and South
America; Italy, Palestine and Egypt in the Palaearctic region; South
Africa, and India.

Hosts of Eutetranychus banksi, in addition to citrus, include croton,
Ficus sp., Oncoba spinosa, and Flacourtia indica as far as our own
studies are concerned. Published records are from citrus, castor bean,
velvet bean, almond, sapota. Cassia fistula , and Zizy-phus jujuba.

Eutetranychus pantopus ( Berlese), new combination

T etrany chus pantopus Berlese, 1910, Redia, 6: 242. Types: two males.

Moreton Bay, Australia, on Ficus sp.; in the Berlese collection.
Anychus latus, Sayed, 1946, Bui. Soc. Fouad ler Ent., 30: 143. W/s-
identification.

124

Spider Mites

The type males of pantopus Berlese agree with the drawing of the
male of latus as determined by Sayed (1946). These specimens as well
as the female illustrated by Sayed differ from banksi by having all of
the dorsal setae long, slender, and tapering. Similar mediodorsal setae
have not been noted in the New World nor in Egypt. Sayed’s material
was apparently from the Sudan on Lebbek trees, and Berlese’s is from
Australia.

Eutetranychus pantopus may represent an extreme variation of the
banksi complex or else a distinct species. Further studies are needed
to determine its true status.

TRIBE TETRANYCHINI RECK

Tetranychinae Reck, 1950, Trudy Inst. Akad. Nauk Gruz. S.S.R., 9: 123;

Reck, 1952, Izd. Akad. Nauk S.S.R. 1952: 25; Reck, 1952, Soobsh.
Akad. Nauk Gruz. S.S.R. , 13(7): 423.

The tribe Tetranychini contains most of the members of the family
Tetranychidae, and particularly most of the species of economic impor-
tance. Their identification is often difficult without representatives of
both sexes, or at least in many cases, males. The aedeagus must be
mounted laterally to see the outline of this simple but often diagnostic
structure.

Members of the Tetranychini may be differentiated from other tribes
in the subfamily by having the empodium well developed - not a tiny
hook or protuberance. The empodium in this tribe is usually represented
by several pairs of ventrally directed, proximoventral hairs, and a dorso-
median clawlike appendage may or may not be developed. When the
dorsomedian empodial claw is not prominent, the proximal pair of empo-
dial hairs may be enlarged (with the others reduced or absent) to form a
pair of clawlike appendages; or else the bases of the empodial hairs may
unite to form a slender, more or less clawlike appendage.

At least for taxonomic purposes, if not for phylogenetic considera¬
tions, there are two major divisions of the tribe Tetranychini. The more
primitive genera resemble the rest of the family in that two pairs of
para-anal setae are present. The caudal pair of para-anals are widely
spaced and laterad or somewhat caudad of the end of the anus in
Metatetranychus and Allonychus, but they are approximate and resemble
a terminal pair of dorsal opisthosomals in Eotetranychus and closely
allied genera ( Schizotetranychus and A' eotetranychus). In Oligonychus
and 7 etranychus, the caudal pair of para-anals are lacking.

125

Subfamily 7 etrany chinae Rerlese

Fig. 93. M etatetranychus ulmi: dorsal aspect of female.

Oudemans (1930) first recognized the significance of the presence
or absence of a pair of caudal setae for generic separation of this group
of mites. He referred to this distinction in terms of whether the clunal
setae are present or absent. This terminology was followed by Geijskes
(1939), Womersley (1940), and Pritchard and Baker (1952).

We now believe that the presence of clunal setae is constant through¬
out the family Tetranychidae, and that a theory of the presence or
absence of the caudal pair of para-anals not only provides an easier
criterion for taxonomic purposes, but it also provides a more acceptable
interpretation for phylogenetic considerations.

The duplex setae are characteristic of the tribe inasmuch as there
are two pairs that are variously located on the dorsum of tarsus 1 and
one pair on the dorsum of tarsus II. The proximal member of each duplex
is comparatively well developed, long enough to cross the distal member.

126

Spider Mites

Fig. 94. Metatetrany chus ulmi: tarsus I of female, with
dorsal enlargement of appendages.

The peritreme is comparatively simple distally, often ending in a
simple bulb. Sometimes the distal end is recurved, consisting of several
compartments, and rarely the recurved end possesses irregular diverti¬
cula.

Members of the tribe Tetranychini have the ability to produce silken
strands, and some spin copious webbing when colonies develop. Some
early workers believed the silk to originate from near the anus, but
later (Claparede, 1868) it was recognized that the silk glands are at
the anterior end of the body. Blauvelt (1945) believed the silk to orig¬
inate from two types of glands, one originating above the anterior coxae
and the other above the base of the palpi. Grandjean (1948) considered
the silk glands to be in the palpi.

Key to the genera of Tetranychini

1.

Opisthosoma with two pairs of para-anal setae

2

127

Subfamily 7 etrany chinae Herlese

1. Opisthosoma with a single pair of para-anals . 6

-MO. Empodium with a simple, clawlike dorsal member and with paired
proximoventral hairs . 3

2. (1). Empodium not clawlike and with paired proximoventral hairs. 4

3. (2). Empodium with a simple “claw” nearly as long as three pairs of

similar, proximoventral hairs; tarsus I with duplex setae adjacent
near distal end of segment .... Metatetranychus (p .127)

3. (2). Empodium with “claw” much shorter than the longest of the

dissimilar proximoventral hairs; tarsus 1 with duplex setae sep¬
arated along dorsal surface of segment . . . Allonychus (p. 137)

4. (2). Empodium with the two proximoventral hairs enlarged forming

two clawlike appendages, the dorsal hairs very short if present
. Schizotetranychus (p.225)

4. (2). Empodium (excluding legs 1 and II of males) comprised of three

pairs of hairs of similar length, the proximal member of which is
slightly the stronger, or else with the hairs united proximally to
form a single appendage . 5

5. (4). 1 '.mpodium forming a single, slender appendage on at least proxi¬

mal one-half . A eotetranychus (p.215)

5. (4). Empodium (excluding leg I and II of male) composed of three

pairs of hairs . Eotetranychus (p.138)

6. (1). Empodium clawlike and somewhat shorter than or about as long

as proximoventral hairs; peritreme usually straight distally and
ending in a simple bulb; tarsus I usually with duplex setae ad¬
jacent and placed near distal end . . . Oligonychus (p.270)

6.(1). Empodium with clawlike dorsal member much shorter than proximo¬
ventral hairs or else rudimentary; peritreme recurved distally
or rarely anastomosing; tarsus I with duplex setae widely spaced
on dorsum of segment . Tetranychusi p.373)

GENUS METATETRANYCHUS OUDEMANS

Metatetranychus Oudemans, 1931, Ent. Ber., 8(177): 199; Oudemans,
1931, Ent. Ber., 8(178): 224; Geijskes, 1939, Meded. Landbouwh.
ftageningen, 42(4): 41; Zacher, 1933, Mitt. zool. Mus. Berl.,
19: 586; (Vomersley, 1940, Trans. Hoy. Soc. S. Australia, 64:
260; McGregor, 1950, Amer. Midi. Nat., 44: 329. Type of genus:
Tetranychus ulmi Koch; by original designation.

128

Spider Mites

A

j

Members of the genus Metate¬
tranychus have the dorsal setae of
the body borne on strong tubercles.
The empodial claw bears three pairs
of proximoventral setae that are
similar in length. There are two
pairs of para-anal setae, and the
caudal pair are spaced widely but
similar to the anterior pair and located
caudad of the anus. These characters
will serve to identify the genus.
The duplex setae of tarsus I are
adjacent and placed near the distal
end of the segment. The peritreme
is straight distally, ending in a
simple bulb.

Two species of Metatetranychus
are definitely known to occur in
North America. These species are
similar morphologically, but differ
considerably in color, biological habits, and geographical distribution.
Both species are found in many parts of the world.

Fig. 95. Metatetranychus ulmi:
aedeagus.

Key to North American Species of Metatetranychus

1. Hysterosoma with outer sacrals similar in length to clunals,
each about one-third as long as inner sacrals . . . citri (p. 133)

1. Hysterosoma w'ith outer sacrals about two-thirds as long as inner
sacrals and the clunals about one-third as long . . ulmi (p.128)

Metatetranychus ulmi (Koch)

European Red Mite

(Figures 93, 94, 95)

Tetranychus ulmi Koch, 1836, Dent Crust. Myr. Arach., 1: 11; Berlese,
1886, Acari dann. Piante Colt., p. 22. Described from specimens
from Regensburg, Germany, on elm.

Oligonychus ulmi. Hirst, 1920, Proc. Zool. Soc. Lond., 1920 : 58.
Metatetranychus ulmi., Oudemans, 1921, Ent. Ber., 8(177): 198; Geijskes,
1939, Meded. Landbouwh. Wageningen, 42(4): 43; Reck, 1941,

129

Subfamily 7 etranychinae Berlese

Fig. 96. Metcitetranyctius citri : dorsal aspect of female.

Soobsh. Akad. Nauk Gruz. S.S. R. (2)9; Gunthart, 1945, Mitt,
schweiz. ent. Ges. 9 : 285; Womerslev, 1940, Trans. Roy. Soc. S.
Austr. , 64: 261; Groves and Massee, 1951, Syn. World Lit. Fruit
Tree Red Spider mite, p. 3; Pritchard and Baker, 1952, Hilgardia,
21(9): 260.

P aratetranychus ulmi, Andre, 1937, 1 til. Appl. Ltud. Acar., p. 21.

T etranychus pilosus Canestrini and Fanzago, not ( Distigmatus ) = 7 et~
ranychus pilosus Donnadieu, 1875, 1876, Atti. Soc. Yen. Trent.,
5: 133; Canestrini and Fanzago, 1878, Atti Reale 1st. \ eneto
Sci. Let. Arti (ser. 5), 4; 150; Canestrini, 1889, Atti Reale 1st.

130

Spider Mites

D

Fig. 97. M etatetranychus citri: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

131

Subfamily 1 etrariy china e Rerlese

\eneto Sci. Let. Arti (ser. 6), 7: 500; Berlese, 1889, Acari Myr.
!Scorp. Prostigmata, 46: 6. Described from specimens from Trevi¬
giano, Italy, from fungus. Secondary homonym.

Paratetranychus pilosus Zacher, 1913, Mitt. Lais, biol. Land-Forst.
Anst., 14: 39; T ragardh, 1915, Centralanst. forsok. jordbr. Knt.
avdel., 20(109): 21; Tragardh, 1915, Z. angevv. Ent., 2: 161;
McGregor, 1919, Proc. U. S. Natl. Mus., 56(2303): 671: Zacher,

1921, Zts. ang. Ent., 7: 184; Carman, 1921, Jour. Econ. Ent., 14:
355; Carman, 1923, Bui. Conn. Agr. Exp. Sta., 252: 103; Essig,

1922, Mo. Bui. Calif. Dept. Agr., 11: 409; Hamilton, 1924, Bui.
Maryl. Agr. Exp. Sta., 264: 1; Andre, 1932, Bui. Mus. Natl. Hist.
Nat. Paris (ser. 2), 3: 531; Carman, 1940, Bui. Conn. Agr. Expt.
Sta., 431: 77; McGregor, 1950, Amer. Midi. Nat., 44: 348.

.1 letatetranychus pilosus, Zacher, 1933, Mitt. Zool. Mus. Berlin, 19: 587.
P aratetranychus pilosus alboguttatus Zacher, 1913, Mitt. kais. biol.
Anst. Land-Forstw., 14: 39. Described from specimens from
Zehlendorf, Germany, on gooseberry. I\'ew synonymy.
Metatetranychus alboguttatus, Oudemans, 1931, Ent. Ber., 8(177): 199.
Paratetranychus pilosus occidentalis McGregor and Newcomer, 1928,
Jour. Agr. lies., 36: 180. Described from specimens from \akima,
Washington, on deciduous fruits, hew synonymy.

7 etranychus mytilaspidis, Ewing (not Riley, 1885), 1912, Jour. Econ.
Ent., 5: 414; Ewing, 1913, Ann. Ent. Soc. Amer., 6: 459. Mis-
identification.

Oligony chus mus corum Oudemans, 1929, Ent. Ber., 7(168): 484. Type
female from Amsterdam, Holland, on moss, hew synonymy.
Metatetranychus muscorurn, Oudemans, 1931, Ent. Ber., 8(178): 232;

Geijskes, 1939, Meded. Landbouwh. Wageningen, 42: 42.

Oligony chus potentillae Oudemans, 1929, Ent. Ber., 7(168): 484. Type:
female, Berlin, Germany, on P otentilla fruticosa; of unknown
disposition, hew synonymy.

Metatetranychus potentillae, Oudemans, 1931, Ent. Ber., 8(178): 233;

Geijskes, 1939, Meded. Landbouwh. Wageningen, 42(4): 43.
Oligonychus alni Oudemans, 1929, Ent. Ber., 8(169): 19. Described
from specimens from Berlin, Germany, on Alnus glutinosa.
Metatetranychus alni, Oudemans, 1931, Ent. Ber., 8(178): 231.
Metatetranychus mali Oudemans, 1931, Ent. Ber., 8(181): 290; Geijskes,
1939, Meded. Landbouwh. Wageningen, 42: 43. Type: female,
Bremen, Germany, on Pirus malus; in the Rijksmuseuni van
Natuurlijke Historie, Leiden, Holland, hleu synonymy.
Metatetranychus canestrinii Oudemans, 1939, Zool. Anz., 127: 78. New
name for T etranychus pilosus Canestrini and Fanzago, not
Donnadieu.

132

Spider Mites

Fig. 98. M etatetranychus citri : A.) appendages of tarsus I of female; B.)
appendages of tarsus III of male; C.) appendages of tarsus I of male.

M etatetranychus ulmi, long known in North America as P aratetrany-
chus pilosus , is a well-known pest of deciduous fruit trees. The body
of the adult female is brick red with whitish dorsal tubercles, and this
coloration serves for ready determination in the field.

Slide preparations of both sexes of the adult may be differentiated
from M etatetranychus citri by having the clunals distinctly shorter than
the outer sacrals.

The E uropean red mite is known from Europe, Georgia, S.S.R., and
throughout the United States, and southern Canada. It is also recorded
from Tasmania and New Zealand, and specimens have been received
from Japan.

Hosts are primarily deciduous trees and bushes belonging to the
family Rosaceae. Fruit trees, namely apple, cherry, pear, peach, plum,
and prune are cortimon hosts, as well as berries and the ornamental
shrubs cotoneaster and pyracantha. Metatetranychus ulmi also occurs
commonly on elm. Other known hosts are almond, walnut, mountain ash,
and black locust.

Metatetranychus ulmi overwinters in the egg stage on the twigs of
trees. The egg is red, slightly flattened and radially striate dorsally,
and with a dorsal stipe. Feeding injury occurs on the upper surface of
the leaf, and very little or no webbing is spun. Groves and Massee
(1951) present an extensive, annotated bibliography of this mite.

Metatetranychus citri (McGregor)
Citrus Red Mite
(Figures 96, 97, 9H, 99)

133

Subfamily 7 etrany chinae Herlese

l etranychus mytilaspidis, Hanks, 1900 (not Hiley, 1885), U. S. Dept.
Agr. Div. Ent. lech, Ser., 8: 71; Quayle, 1912, Calif. Agr. Exp.
Sta. Bui., 234: 487; Ewing, 1913, Ann. Ent. Soc. Amer., 6: 459.
M isidentification.

P arat etrany chus mytilaspidus, Hanks, 1915, U. S. Dept. Agr. Hep.,
108: 37. Misidentification.

T etrany chus citri McGregor, 1916, Ann. Ent. Soc. Ainer., 9: 28. lypes:
males and females, Orlando, Florida, on lemon; in the U. S.
National Museum.

Paratetranychus citri, McGregor, 1919, Proc. U. S. Natl. Mus., 56(2303):
672; McGregor and Newcomer, 1928, Jour. Agr. Res., 36: 157;
McGregor, 1950, Amer. Midi. Nat., 44: 335.

Me tat etrany chus citri, Heck, 1941, Soobsh. Akad. Nauk Gruz. S.S.R.,
2(9); Haker and Wharton, 1952, Introd. Acar., p. 214.

Adults of Metatetranychus citri may be recognized in nature by having
the entire body, including the strong tubercles, velvety reddish or pur¬
plish. Mounted specimens differ from those of M. ulmi by having the

outer sacrals and the clunals all
similar in length, about one-third
as long as the inner sacrals.

McGregor (1916) first showed
that T etrany chus mytilaspidis can¬
not refer to a tetranychid.

The citrus red mite is known
from California (from Sacramento
southward) and the southeastern
United States. Specimens also
have been received from South
Africa; Canton, China, and southern
Japan. It undoubtedly occurs in
most citrus growing areas of the
world.

Hosts are primarily broadleaved
evergreen trees and shrubs. Meta-
tranychus citri is sometimes very
abundant on citrus and broad¬
leaved evergreen ornamentals such
as Choisva, Xylosma, Elaeagnus,

Fig. 99. .1/ etatetranycnus citri:
aedeagus.

134

Spider Mites

Fig. 100. Allonychus brazili ensi s: dorsal aspect of female,
with enlargement of peritreine.

Umbellularia, and Prunus laurocerasus. Incidental hosts include rose,
almond, pear, castor bean, and grasses.

Large populations that build up on favorite hosts such as citrus may

135

Subfamily T etmny chinae Herlese

Fig. 101. Allonychus braziliensis : above, tibia and tarsus I of
female; below, tibia and tarsus II of female.

give rise to infestations on neighboring plants such as roses. Our ob¬
servations tend to show that such a secondary host is not favorable
for continuation of the species.

Reproduction continues throughout the year, with the greatest popu¬
lations being produced during the spring and fall under semi-tropical
conditions (cool winters). The egg is red, slightly flattened and radially

136

Spider Mites

Fig. 102. Allony chus brazili ensis: A.) ventrocaudal view of female opis-
thosoma; B.) appendages of tarsus I of female; C.) dorsocaudal view of female
opisthosoma; D.) terminal segment of female palpus.

striate dorsally, and there are usually fine guy fibrils arising front the
tip of the dorsal stipe. Feeding injury occurs on the upper surface of
the leaves and on the fruit.

Boyce (1948) summarized our knowledge of the biology of the citrus
red mite, and Debach et al. (1950) present studies on the effect of
natural enemies on the mite.

Metatetranychus spinigerus (Lucas)

Tetranychus spinigerus Lucas, 1849, Hist. Nat. Anim. Art., in Explor.
Sci. d’Algerie, Zool., 5(1): 309. Described front specimens from
Canstantine, Algeria, on Antirrhinum orontium.

Metatetranychus spinigerus, Oudemans, 1931, Ent. Ber., 8(177): 199;
Oudemans, 1937, Krit. Hist. Overs. Acar., 3(C): 1058.

The original description and figures of spinigerus indicate that

137

Subfamily Tetrany chinae fieri ese

Oudemans was correct in referring this species to the genus Meta-
te trany chus. It is possible that this is an earlier name for M. citri, but
the tetranychid fauna of the Mediterranean area should be better known
before synonymy is made.

Metatetranychus hadzhibejl iae Reck

M etatetranychus hadzhibejliae Heck, 1947, Soobsh. Akad. Nauk Gruz.
S. S. R., 8(7). De scribed from specimens from Georgia, S. S. R.,
on Ficus carica.

Vie have not seen the description of this species.

ALLONYCHUS PRITCHARD AND BAKER, new genus

Type of genus. — Tetranychus braziliensis McGregor.

The genus Allonychus is proposed for a single species that is closely
allied to \l etatetranychus, but it appears to bear a relationship with
the genus Tetranychus similar to the relationship that M etatetranychus
bears with Oligonychus.

The most distinctive characteristic of Allonychus is in the compo¬
sition of the empodium. This structure differs from that of all other
tetranychids in consisting of a mediodorsal spur that bears a tiny pair
of dorsal hairs, and in having four pairs of proximoventral hairs that
are dissimilar in length.

Allonychus is considered by us to be closely allied to the genus
M etatetranychus because there are two pairs of para-anals; the caudal
pair is nearly as widely spaced as the anterior pair and is placed lat-
terad of the anus. However, the duplex setae on tarsus I are separated
lengthwise of the dorsal surface of the segment, the dorsal setae of
the body are not set on tubercles, and the integumentary striae are
longitudinal between the third dorsal hysterosomals and inner sacrals
as in most species of T etranychus.

Allonychus braziliensis (McGregor), new combination
(Figures 100, 101, 102)

Septanychus tumidus, ftomersley, 1942, Trans. Roy. Soc. S. Australia,
66: 87. Misidentification.

138

Spider Mites

Septanychus braziliensis McGregor, 1950, Amer. Midi. Nat., 44: 318.

Types: Five females, Vicosa, Brazil, on quince; in the U. S.

National Museum.

Our reference to Womersley s record of this species from Victoria,
Australia, is not authenticated. Womersley presents an excellent photo¬
graph of copious webbing spun by the mite on buffalo grass.

Specimens studied by us are the types and a number of females from
Boaca, Nicaragua, February 28, 1951 (E. J. llambleton), on leaves
of an unknown tree. McGregor recorded banana as a host.

GENUS EOTETRANYCHUS OUDEMANS

Eotetranychus Oudemans, 1931, Ent. Ber., 8(178): 224; Geijskes, 1939,
Zacher, 1933, Mitt. Zool. Mus. Berlin, 19: 587; Geijskes, 1939,
Meded. Landbouwh. Wageningen, 42(4): 30. Type of genus :

Trombidium tiliarium Hermann, referred to as A cams telarius
Linnaeus; by original designation.

Apotetranychus Oudemans, 1931, Eng. Ber., 8(178): 225; Geijskes, 1939,
Meded. Landbouwh. Wageningen, 42(4): 32. Type of genus:

Apotetranychus muscicola Oudemans; monobasic and by original
designation. New synonymy.

Platytetranychus Oudemans, 1931, Ent. Ber., 8(178): 224; Oudemans.

1931, Ent. Ber., 8(181): 293; Geijskes, 1939, Meded. Landbouwh.

Wageningen, 42(4): 45. Type of genus: T etranychus gibbosus

Canestrini: by original designation and monobasic. New synon¬
ymy.

Mites belonging to the genus Eotetranychus may be recognized by
having the caudal pair of para-anals (the postanal setae) present, to¬
gether with having the empodium (except for leg 1, and sometimes II,
of the male), consisting of three pairs of hairs.

The proximal pair of empodial hairs is typically stronger than the
other two pairs, but the development is not as great as that of
Schizotetranychus, a genus derived from Eotetranychus. The base of
the empodial hairs may form a short stalk, but the base is not pro¬
longed greatly as in N eotetranychus.

Empodium i of the male sometimes resembles that of the female by
having three pairs of fine hairs. More often, however, the hairs are

139

Subfamily I etrany chinae Berlese

Fig. 103. Eotetranychus, caudoventra] aspects of the female
opisthosoma, showing types of striae.

reduced to slender or short teeth, so that the empodium appears as
a pair of divergent, short and broad, trifid plates. The dorsal tooth
is the smallest, and sometimes it is nearly absent. Empodia III and
IV' of the male resemble the female empodium.

The genus Apotetranychus is considered to be a synonym, because
specimens that undoubtedly represent the type of the genus have been
studied by us and they present no morphological differences of generic
significance. Oudemans considered the comparative shortness of the
dorsal setae of the body as well as the apparent shape of the alveoli
in which they are inserted to be of generic value.

Platytetranychus is also considered to be a synonym of Eotetrany¬
chus. Oudemans (1931) regarded the type of the genus, T etranychus
gibbosus Canestrini, to be lacking a pair of caudal setae; but his des¬
cription of the genus is obviously based on the poor drawing of Berlese.
The Berlese drawing indicates that gibbosus is closely related to E.
libocedri and E. thujae, both of which also occur on conifers. No other
species with an empodium consisting of only three pairs of hairs are
known from conifers.

140

Spider Mites

planki

multidicitul i

I ibocedri

perplexus

thujae

sexmaculatus

maivastris

yumensi s

Fig. 104. Eotetranychus, aedeagi.

Eotetranychus resembles the genus Tetranychus, a more distant
relative, in that the empodium consists of only three pairs of hairs.
However, representatives of Eotetranychus, in addition to possessing
two pairs of para-anals, have the duplex setae on tarsus I adjacent.
The peritreme is variable with regard to its termination, but it often
ends in a simple bulb.

The dorsal striae of the female (as well as the male) are usually,
but not always, transverse between the third pair of dorsocentral
hysterosomals and the sacrals.

141

Subjamily I etrany chinae lierlese

cory I i

popul i

weldoni

deflexus

hi coriae

smit'ni

Fig. 105. Eotetranychus, aedeagi.

pal I idus

The characteristics of the integumental striae on the genital flap
and just anterior to the flap were noted by C. A. Fleschner to be of
value for species differentiation. Although this character appears to
be variable in related genera, it has proved to be of considerable sig¬
nificance for determination of Eotetranychus females.

The number of tactile setae on tibia I, II, and III are here noted
to be of value for species recognition or assignment to related groups
of species. Similarly the number of tactile setae on the proximal portion
of tarsus I, as well as the shape of empodium I of the male, is valuable
for identification. These characters are delineated for the first time
for most of the species.

142

Spider Mites

Adult mites are usually tiny, with the body of the female slender.
They are strawcolored or somewhat greenish with several spots of
dark pigment along each side of the body. Species found in temperate
regions hibernate as bright, lemon-yellow females. The eggs are typi¬
cally pearly, globular, and with a tiny dorsal stipe.

Members of the genus Eotetranychus are found feeding on the under
surface of leaves. They reside primarily along the veins, forming small
colonies, and their webbing is usually sparse.

Several acarologists have misdetermined the genus Eotetranychus
as defined by Oudemans and interpreted by us. McGregor (1950) used
the character of the dorsal striae of the female hysterosoma (apparently
as a subgeneric character) and, consequently, included erroneously
several species of Tetranychus. Ugarov and Nikolskii (1937) plainly
included only species properly belonging to Tetranychus. E. inexpec -
tatus Andrd and E. cucurbitacearum Sayed are other species of Tetrany¬
chus that were erroneously assigned to Eotetranychus.

In our systematic treatment of the genus Eotetranychus, species
groups are recognized as an aid in presenting morphological characters
and as a means for ready identification. We are not sure that the groups
are discrete units phylogenetically. For instance, E. steganus and E.
clitus both closely resemble members of the liliarium Group; but the
leg chaetotaxy of each is distinct, and it is convenient to discuss
them separately.

Key to North American species of EOTETRANYCHUS
Females

1. Tibia II with five to seven tactile setae . 2

1. Tibia II with eight tactile setae (Tiliarium Group) ... 8

2. (1). Second tibia with five tactile setae . 3

2. (1). Second tibia with six or seven tactile setae . 6

3. (2). Peritreme with a distal hook bearing irregular projections; on

honey locust (Multidigituli Group). . . . multidigituli (p.163)

3. (2). Peritreme ending in a simple bulb . 4

4. (3). Dorsocentral hysterosomals longer than longitudinal intervals

between them; on palmetto (Steganus Group) . steganus (p.167)

4. (3). Dorsocentral hysterosomals shorter than longitudinal intervals

between them; on cupressaceous conifers (Libocedri Group). . 5

5. (4). I ibia 1 with nine tactile (anil one sensory) setae; tibia III with

five tactile setae . libocedri (p.154)

5. (4).

6. (2).

6.(2).

7.(6).

7.(6).

8.(1).

8.(1).

9.(8).

9. (8).

10. (9).

10. (9).

11. (10).
11.(10).

12.(11).

12.(11).

13.(12).

13. (12).

14. (9).
14.(9).

143

Subfamily I etrany chinae Herlese

Iibia I with seven tactile (and one sensory) setae; tibia 111
with four (or three) tactile setae . thujae (p.159)

Body with dorsal setae slender and tapering, much longer than
longitudinal intervals between them; tibia 11 with six setae

(Clitus Croup) . clitus (p.170)

Body with dorsal setae subclavate, no longer than longitudinal
intervals between them; tibia II typically with seven setae
(Caribbeanae Group) . 7

Dorsocentral hysterosonials not over one-half as long as inter¬
vals between them; propodosomal integument with irregularly
arranged dots or granulations mediodorsally, and usually

around tubercles on the hysterosoma . . caribbeanae (p.147)

Dorsocentral hysterosonials about as long as intervals between
them; propodosoma with anastomosing striae mediodorsally, as
well as on lateral parts of the hysterosoma . . planki (p.148)

Tarsus I with four tactile setae proximal to duplex setae .

. perplexus (p. 175)

Iarsus I with five tactile setae proximal to duplex setae . .9

Area immediately anterior to genital flap with longitudinal or

irregular striae . 10

Area immediately anterior to genital flap with transversely
parallel striae . 14

Genital flap with only transverse striae . 11

Genital flap with longitudinal striae on anterior portion ,
. sexmaculatus (p.202)

Area immediately anterior to genital flap with irregular striae .

. pallidus (p . 21 1 )

Area immediately anterior to genital flap with only parallel,

longitudinal striae . 12

Peritreme straight distally . ecclisis (p. 210)

Peritreme strongly hooked distally . 13

Palpus with terminal sensillum twice as long as broad at base

. hicoriae (p.21l)

Palpus with terminal sensillum one and one-half times as

long as broad at base . smithi (p.192)

Tarsus II with duplex setae subequal in length .

. willamettei (p. 1 87)

Tarsus II with proximal member of duplex much shorter than
distal member . 15

144

Spider Mites

15.(14). Peritreme anastomosing distally . populi (p.189)

15. (14). Peritreme straight distally or with a simple bend or hook . 16

16. (15). Peritreme straight distally, rarely bent . 17

16.(15). Peritreme with a strong hook . . uncatus ; weLdoni; malvastris;

frosti; yumensis; lewisi • • . . (pp. 183, 191, 192, 199 , 205)

17.(16). Palpus with terminal sensillum twice as long as wide at base

. deflexus (p.206)

17.(16), Palpus with terminal sensillum more than two times as long
as wide at base . 18

18.(17).

18.(17).

Palpus with terminal sensillum two and one-half times as long

as wide at base . carpini (p.179)

Palpus with terminal sensillum three times as long as wide
at base . coryli (pj.83)

Males*

The male of caribbeanae is unknown.

1. Tibia II with five to seven tactile setae . 2

1. Tibia II with eight tactile setae (Tiliarium Group) ... 7

2. (1). Second tibia with two sensory setae; on cupressaceous conifers

(Libocedri Group) . 3

2. (1). Second tibia without sensory setae; (rarely with a single

sensory seta); on other hosts . 4

3. (2). Aedeagus with distal portion slender and parallel sided, the

caudal end rounded . thujae (p.159)

3. (2). Aedeagus narrowing only slightly and with the caudal end

emarginate . libocedri (p.154)

4. (2). Aedeagus bent ventrad . 5

4. (2). Aedeagus curved strongly dorsad and tapering to an acute tip

(Ste ganus Group) . steganus (p.167)

5. (4). Aedeagus with distal portion sigmoid and tapering (Clitus

Group) . clitus (p.170)

5. (4). Aedeagus with a terminal knob . 6

6. (5). Peritreme anastomosing distally; knob of aedeagus with a long

caudally directed angulation; dorsal setae of body not on
tubercles (Multidigituli Group) . . . multidi gituli (p. 163)

6.(5). Peritreme straight distally, ending in a simple bulb; knob of
aedeagus with both angulations very short; dorsal setae of

145

Subfamily I etrany chinae Berlese

7.(1).

7. (1).

8. (7).

8. (7).

9. (8).

9. (8).

10. (9).

10. (9).

11. (10).
11.(10).

12.(11).

12.(11).

13.(9).

13. (9).

14. (8).

14. (8).

15. (14).

15. (14).

16. (15).

16. (15).

17. (16).

17. (16).

18. (15).

18. (15).

19. (18).

body borne on strong tubercles (Caribbeanae Group)
. . . . planhi (p.148)

Aedeagus enlarged at distal end to form a terminal knob
. perplexus (p.175)

Aedeagus tapering distally, without a terminal enlargement 8

Aede agus linear, long, slender, and caudally directed . , 9

Aedeagus not forming a linear shaft . 14

Aedeagus with a strong wave near the middle and tapering to

a point . 10

Aedeagus with a broad curve medially and with the distal end
rounded . 13

1 arsus 11 with both members of the duplex setae about equal

in length . willamettei (p.187)

Tarsus II with the proximal member of the duplex much shorter
than the distal member . . 11

Peritreme strongly hooked distally . . . uncatus (p.l 83 )

Peritreme straight distally or bent . 12

Peritreme straight distally, ending in a simple bulb

. carpini (p.l 79)

Peritreme bent at distal end . coryli (p.183)

Peritreme anastomosing distally . populi (p.189)

Peritreme with a simple hook distally . . iveldoni (p.191)

Aedeagus forming a triangle, the lower margin straight or

nearly so . malvastris (p.192)

Aedeagus obviously curved or bent dorsad or ventrad . . 15

Median portion of aedeagus curved or bent dorsad ... 16

Median portion of aedeagus curved or bent ventrad ... 18

Aedeagus shallowly bent dorsad . 17

Aedeagus abruptly bent dorsad . frosti (p.l 99)

Aedeagus abruptly constricted at end of curvature to form a

slender distal stylet . smithi (p.l 92)

Aedeagus gradually narrowing beyond bend . yumensis (p.l9Q)

Aedeagus abruptly declivate, the bent portion forming an acute

angle . 19

Aedeagus more shallowly bent, the distal end forming an obtuse
angle . 20

Shaft of aedeagus abruptly constricted at bend; peritreme with
distal end forming a weak angulation; dorsal setae of body

146

Spider Mites

slightly longer than intervals between them . pallidus (p. 21 1 )

19.(18). Shaft of aedeagus gradually narrowing to bend; peritreme with
distal end strongly hooked; dorsal setae of body much longer
than intervals between them . hicoriae (p.211)

20.(18). Aedeagus with bent portion sigmoid and evenly tapering, the

tip directed caudally . 21

20.(18). Aedeagus with bent portion not sigmoid, the tip abruptly nar¬
rowed and caudoventrally directed . . . sexmaculatus (p.202)

21.(20). Bend of aedeagus very gradual; palpus with well-developed

terminal sensillum . lewisi (p.205)

21.(20). Bend of aedeagus abrupt; palpus with terminal sensillum
rudimentary . 22

22.(21). Terminal segment of palpus with tapering sensilla subequal in
length; aedeagus gradually tapering through bend

. deflexus (p.206)

22.(21). Terminal segment of palpus with tapering sensilla very dis¬
similar in development; aedeagus slightly widened at bend
. ecclisis (p.210)

Caribbeanae Group

Adults of the Caribbeanae Group may be recognized by the peculiar
integument on the dorsum of the body. The mediodorsal portion of the
propodosoma, and usually some of the hysterosoma bears broken, very
irregular striae rather than the parallel striae found in other members of
the genus. Moreover, the dorsal setae of the body are clavate or near¬
ly so.

Iibia I of the female bears seven or nine tactile and one sensory
setae; tarsus I bears four tactile and one sensory setae proximad of
the duplex setae. Iibia II bears seven tactile setae, and tibia III bears
six tactile setae. The empodium of the female has a moderately long
base before division into six hairs. Tibia I of the male possesses nine
tactile setae plus four sensory setae; and tibia II has seven tactile
setae; and tibia III has six tactile setae. Tarsus I bears four tactile
and three sensory setae proximal to the duplexes. Empodium I of the
male consists of a slender, moderately elongate base, with three short
teeth on each side distally.

Two species, both of tropical distribution, belong to this group.

147

Subfamily l etrany chinae lierlese

Fig. 106. Eotetranyckus caribbeanae : dorsal aspect of female, with enlarge¬
ment of integumental striations, Key West, Florida, Cassava.

Eotetranychus caribbeanae (McGregor), new combination
(Figures 106, 107)

T etranychus caribbeanae McGregor, 1950, Amer. Midi. Nat., 44(2): 283.
Types: females, Loiza, Puerto Rico, on cassava; in the U. S.
National Museum.

The female of Eotetranychus caribbeanae may be recognized readily
by having many of the dorsal striae anastomosing; and the striae are
composed of short dashes rather than dots. The dorsocentral setae of
the hysterosoma are less than one-half as long as intervals between
their bases, and they widen to near the tip. Other dorsal setae of the

148

Spider Mites

Fig. 107. Eotetranychus caribbeanae : above, tibia and tarsus I of
female; below, tibia and tarsus II of female.

body are longer, spatulate and set on tubercles. In the female, tibia I
bears seven tactile setae plus a sensory seta. The male is unknown.

In addition to the types, specimens have been studied from Coral
Gables, Florida (0. D. Link), on Jamaica dogwood; Key West, Florida
(L. W. Holley), on cassava; and South Miami, Florida (A. E. Pritchard),
on Dalbergia sisso.

Eotetranychus planki (McGregor), new combination
(Figures 108, 109, 110, 111, 112, 113)

Tetranychus planki McGregor, 1950, Amer. Midi. Nat., 44(2): 300. Types:
males and females, Mayaguez, Puerto Rico, on Erythrina berte-
roana; in the U. S. National Museum.

The female of Eotetranychus planki may be readily differentiated
from other species included in the genus by having the mediodorsal
portion of the propodosoma, as well as broad areas around the dorsal
hysterosomals all with the integument irregularly dotted. In some of
the females from Argentina, however, the hysterosomal dotting is strong¬
ly reduced. The dorsal setae of the body are slender, each slightly

149

Subfamily 7 etranychinae lierlese

Fig. 108. Eotetranychus planhi : dorsal aspect of female,

Trinidad, Cajanus indicus.

enlarged near the distal end. Dorsocentral hysterosomals are approx¬
imately as long as intervals between them and not differentiated from
most other dorsal setae.

The female bears nine tactile and one sensory seta on tibia I.
Eotetranychus planhi has been known only from specimens from
western Puerto Rico, on Erythrina. Additional specimens have been

150

Spider Mites

I

151

Subfamily l etrany chinae Berlese

B

Fig. 110. Eotetranychus planki : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male; all from Trinidad.

152

Spider Mites

Fig. 111. Eotetranychus planki : lateral aspect of
male, Argentina, Cassia sp.

Fig. 112. Eotetranychus planki: above, appendages of male tarsus I; below,
appendages of female tarsus 1 (all from lrinidad).

153

Subfamily 7 etrany chiriae Berlese

Fig. 113, Eotetrany chus plcmki: aedeagus,
Puerto Rico.

studied from the type locality, Mayagiiez, Puerto Rico (H. k. Plank),
on Soya max, P uereria phaseoloides, and “kudzu” leaves; Santa Maria,
lrinidad (R. G. Fennah), on Cajanus indicus; and Concordia, Argentina
(L. C. knorr), on Cassia occidentalis.

Libocedri Group

Members of the Libocedri Group may be recognized by having the
dorsal setae of the body, especially the dorsocentral hysterosomals,
very short, together with having only five tactile setae on tibia II, and
the peritreme ending in a simple bulb.

Tibia I of the female bears seven or nine tactile and one sensory
setae; tibia II rarely may bear one or two sensory setae in addition
to the five tactile setae; tibia III bears three to five tactile setae. The
tibiae of the male resemble those of the female with regard to tactile
setae, but there are five sensory setae on tibia I and two sensory setae
on tibia II and one or two sensory setae on tibia III. Tarsus I bears
three to five tactile and one or two setae proximal to the duplex setae.

Members of the Libocedri Group are found only on cupressaceous
conifers. No other species of Eotetranychus are known from similar
hosts.

154

Spider Mites

Fig. 114. Eotetrany chus libocedri : dorsal aspect of
female, Texas, Arizona cypress.

Eotetrarrychus libocedri (McGregor), new combination
(Figures 114, 115, 116, 117,)

7 elranychus libocedri McGregor, 1936, Ann. Ent. Soc. Amer., 29(4):
771; McGregor, 1950, Amer. Midi. Nat., 44: 289. Types: males
and females, Camp Nelson, California, on Libocedrus decurrens;
in the U. S. National Museum.

155

Subfamily T etranychinae Berlese

Fig. 115. Eotetrany chus libocedri : A.) tibia and tarsus 1 of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus 1 of male; D.) tibia and tarsus
II of male.

156

Spider Mites

Fig. 116. Eotetrany chus libo cedri- above, appendages of tarsus 1
of male; below, appendages of tarsus I of female.

Adults of Eotetrany chus libocedri
may be recognized by having the
dorsocentral hysterosomals very short
and tapering (sometimes with a slight
medial enlargement), together with
the distinctive leg chaetotaxy.

The dorsal propodosomals vary
considerably in length, and there
is some variation in the humeral and
dorsolateral hysterosomals. The
dorsocaudal hysterosomals are often
conspicuously longer than the
dorsocentrals. Tibia I of the female
bears nine tactile setae, and tarsus
I bears five tactile (and sometimes
one sensory) setae proximal to the
duplex setae. Tarsus I of the male
bears four tactile and two sensory
setae proximal to the duplex setae. A
tactile member of the two tactile
and one sensory setae that are ven-
trad of the duplexes may appear to

Fig. 117. Eotetrany chus libocedri :
aedeagus, Texas, Arizona cypress.

157

Subfamily Tetranychinae lierlcse

Fig. 118. Eotetrany chus thujae : dorsal aspect of
female, Maryland, arbor vitae.

be slightly proximal. The aedeagus of Eotetranychus libocedri is dis¬
tinctive. It consists of a simple rod slightly narrowing distally and
laterally emarginate at the tip.

This species is known from cupressaceous conifers in the western
and southwestern United States. In addition to the types, specimens
have been studied from Danville, California (A. E. Pritchard), on Thuja
sp. and Cupressus sp.; Murietta, California (A. E. Pritchard), on Italian
cypress; Camp Nelson, California (E. ft. Baker), on incense cedar:
San Diego, California (D. F. Palmer), on cypress; \akima, ftashington

158

Spider Mites

Fig. 119. Eotetranychus thujae : A.) tibia and tarsus 1 of female; B.) tibia
and tarsus 11 of female; C.) tibia and tarsus 1 of male; D.) tibia and tarsus II
of male; all from type material.

159

Subfamily T etranychinae Herlese

Fig. 120. Eotetranychus thujae : aedeagus.

(1.. Baker), on arborvitae; l tah (G. F. Knowlton), on juniper; and
^tsleta, Iexas (P. Nettervill e), on Arizona cypress.

Eotetranychus thujae [McGregor), new combination
(Figures 118, 119, 120)

T etranychus thujae McGregor, 1950, Amer. Midi. Nat., 44(2): 303. Types:
males and females, Monticello, Florida, on arborvitae and “ever-
greens”; in the U. S. National Museum.

Eotetranychus thujae is closely allied to E. libocedri, and the adults
similarly have very short dorsocentral hysterosomals. However, these
setae are enlarged near the distal end, and the leg chaetotaxy and the
aedeagus are considerably different. There is variation in the length
of the second and third dorsal propodosomals. Tibia I of the female
bears seven tactile and one sensory setae, and tarsus I bears three (or
four) tactile setae that are definitely proximal to the duplex setae.
Tarsus I of the male similarly bears three tactile and one sensory setae
proximally. The tarsus is abruptly declivate just beyond the duplex
setae, and the two ventral tactile and one lateral sensory setae ac¬
companying the duplexes may appear to be placed slightly more
proximally. The aedeagus is distinctive in that it consists of a sharply

160

Spider Mites

161

Subfamily I etrany chinae Berlese

Fig. 122. Eotetrany chus multidi gituli: A.) tibia and tarsus I of female,
with enlargement of appendages; B.) tibia and tarsus II of female; C.) tibia
and tarsu? I of male; D.) tibia and tarsus II of male, with enlargement of append¬
ages of tarsus I.

162

Spicier Mites

/

Fig. 123, Eotetranychus multi digituli: aedeagus.

narrowed rod, forming a fingerlike distal end thdt is broadly rounded
at the tip.

This species is known from the eastern and southwestern United
States on cupressaceous conifers. In addition to the types, specimens
have been examined from Beltsville, Maryland (E. W. Baker), on arbor-
vitae; St. Petersburg, Florida (E. W. Baker), on juniper; Williana,
Louisiana (L. D. Newsom), on Juniperus virginiana; and Oklahoma
City, Oklahoma (A. E. Pritchard), on juniper. McGregor also recorded
specimens from Alabama.

Eotetranychus gibbosus ( Canestrini ), new combination

T etranychus gibbosus Canestrini, 1889, Atti Reale 1st. Veneto Let.
Sci. Arti (ser. 6), 7(2): 501; Berlese, 1886, Acari, Myr. Scorp.,
72, no. 7. Described from specimens from Trentino and Padova,
Italy, on conifers.

163

Subfamily 1 etrany chinae Herlese

P latytetranychus gibbosus, Oudemans, 1931, Ent. Ber., 8(178): 224;

Geijskes, 1939, Meded. Lundbouwh. Wugeningen, 42(4): 45.

1 he original description and Canestrini’s illustration indicate that
gibbosus is allied to Eotetranychus thujae and E. libocedri. Berlese’s
illustration also indicates that it may be a member of this group, even
though his specimen could represent Paratetranychus ununguis.

Oudemans apparently based his description of the genus P latytetrany¬
chus on Berlese’s poor figure, and he considered the postanals to be
absent in his key (1931). Ceijskes (1939) followed Oudemans in con¬
sidering the absence of these setae to be a key character.

Definite identification of this species must be based on topotype
material.

Multi digituli Group

Adults of the Multidigituli Group may be differentiated from other
members of the genus by having the peritreme forming an anastomosing
chamber distally, together with having the dorsocentral hysterosomals
shorter than the longitudinal intervals between them.

Tibia 1 bears seven tactile plus one sensory setae in the female,
seven tactile plus four or five sensory setae in the male; tibia II bears
five tactile setae in the female and an additional two sensory setae in
the male; tibia III bears five tactile setae in both sexes. Tarsus I is
abruptly declivate distally, and it bears three tactile setae proximally,
with one sensory seta in the female and three sensory setae in the male.

The aedeagus is distinctive in that it bends sharply ventrad and
forms a distal knob the distal angulation of which is much longer than
the anterior angulation.

The palpus bears three tactile and four sensory setae as is typical
of the family.

The Group contains a single species.

Eotetranychus multidigituli {Ewing), new combination
(Figures 121, 122, 123)

Tetranychus multidigituli Ewing, 1917, Jour. Econ. Ent., 10(5): 497;
McGregor, 1919, Proc. U. S. Natl. Mus., 56(2303): 654; McGregor,
1950, Amer. Midi. Nat., 44(2): 306. Types: five females, booster,
Ohio, on Gleditsia triacanthos ; in the U. S. National Museum.

164

Spider Mites

Fig. 124. E ote.tr any chus steganus: A.) tibia and tarsus I of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of male.

165

Subfamily I etrany chinae Herlese

Fig. 125. Eotetrany chus steganus: aedeagus;
and appendages of tarsus I of male
with dorsal view.

7 etranychus ellipticus Gannan, 1940, Bui. Conn. Agr. Exp. Sta., 431:
83; McGregor, 1940, Amer. Midi. Nat., 44(2): 284. Types: males
an’d females, New Haven and Glastonbury, Connecticut, on
Gleditsia triacanthos; in the collection of the Connecticut Agri¬
cultural Experiment Station. Aeu’ synonymy.

There is some variation in the length of the dorsal setae of the body
of this species, and they are not widened proximally (as indicated in
Carman’s illustration). In specimens from the northeastern United States
the dorsocentral hysterosomals are longer and possibly more pubescent
than in specimens from the midwestern and southern states.

Eotetranychus multidigituli is known only from honey locust, Gledit¬
sia triacanthos, occurring under the leaves.

The types of both multidigituli and ellipticus (kindly loaned by Dr.
Garman) have been studied, as well as collections from Hamden, Connec¬
ticut (Philip Garman), on honey locust; Washington, D. C. (E. W. Baker),

166

Spider Mites

Fig. 126. Eotetranychus clitus: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

167

Subfamily I etrany chinae H fries e

Fig. 127. Eotetrany chus clitus : A.) terminal segment of palpus of female;
B.) t erminal segment of palpus of male; C.) appendages of tarsus I of female.

on thornless honey locust; Durham, North Carolina (Bruce Boudreaux),
on honey locust; and Natchitoches, Louisiana (L. D. Newsom), on
honey locust.

Steganus Group

The Steganus Group resembles the Tiliarium group in that the dorsal
setae of the body are all long, slender, and tapering. However, tibia II
possesses only five, rather than eight, tactile setae, and there are very
few setae on tarsus I. The aedeagus is also distinctive in forming a
long, dorsally bent stylet.

This group is recognized on the basis of a single species that occurs
on palmetto in Florida.

Eotetranychus steganus Pritchard and Baker, new species
(Figures 124, 125)

Female. — Rostrum reaching beyond middle of femur I. Palpus with
terminal sensillum small and slender. Stylophore emarginate antero-
medially. Tibia I with six tactile and one sensory seta; tarsus I with
a single sensory seta proximal to duplex setae and with a single, ventral

168

Spider Mites

Fig. 128. Eotetranychus clitus : aedeagus.

tactile seta at the level of the duplex setae; tibia II with five tactile
setae; tibia III with three tactile setae. Empodium with three pairs of
hairs, divergent almost from base. Dorsal integument with regular,
parallel, dotted striae. Dorsal setae of body much longer than inter¬
vals between bases, slender and acutely tapering from near base, very
finely pubescent. Length of body, 330p; including rostrum, 410fi.

Male. — Similar to female. Tibia I with six tactile and three sensory
setae; tarsus I with three sensory setae proximal of duplex setae; tibia
II with a sensory seta in addition to the five tactile setae. Aedeagus
with external portion of shaft curved abruptly dorsal, the curved portion
longer than the shaft, needle-like, and tapering. Length of body, 266 p;
including rostrum, 333pi.

Uololype. — Male, St. Petersburg, Florida, July 1, 1952 (E. W. Baker),
on palmetto; type no. 2176 in the U. S. National Museum. P aratypes. —
Seventy-seven females, 59 males, St. Petersburg, Florida, July 1, 3,

169

S

ubfarnily Tetrany chinae lierlese

Fig. 129. Eotetrcmychus muscicola: dorsal aspect of female, Scotland.

and 11, 1952 (E. W. Baker), on palmetto; 2 females, 4 nymphs, Ponte
Vedra, Florida, July 3, 1953 (A. E. Pritchard), on palmetto; 5 females,
South Miami, Florida, July 9, 1953 (A. E. Pritchard), on palmetto; 3
males, 10 females, Miami, Florida, (E. W, Baker), on palmetto.

Clitus Group

The Clitus Group is based on a species that closely resembles
Eotetranychus deflexus, and it is probable that the closest relation¬
ships are with that species. However, E. clitus is distinctive in having
six tactile setae on tibia II.

170

Spider Mites

Fig. 130. Eotetranychus muscicola: above, tibia and tarsus
I of female; below, tibia and tarsus II of female.

Eotetranychus clitus Pritchard and Baker, new species
(Figures 126, 127, 12,3)

The male of Eotetranychus clitus closely resembles that of E. de-
flexus in having the aedeagus tapering and abruptly declivate in a
sigmoid curve. However, the distal segment of the palpus of this sex
bears four sensory sensilla, the terminal sensillum being very long
and slender.

The peritreme forms a strong hook distally, and the clunals of the
female are much shorter than the inner sacrals.

171

Subfamily T etrany chinae Rerlrsr

Fig. 131. Eotetranychus perplexus : A.) tibia and tarsus 1 of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of male.

This species is known only from the southeastern United States, on
low-growing hosts.

172

Spider Mites

B

Fig. 132. Eotetranychus perplexus: A.) appendages of tarsus I of female;
B.) terminal segment of palpus of female; C.) appendages of tarsus I of male;
D.) terminal segment of palpus of male.

Male. — Palpus with terminal sensillum obconical, about three times
as long as broad at base; proximal sensillum of last palpal segment
slender, somewhat longer than the mediodorsal, tapering sensilla. Peri-
treme strongly retrorse distally. Tibia I with nine tactile and four (or
three) sensory setae; tarsus I with four tactile and three sensory setae
proximal to duplexes; empodium I with three pairs of short teeth. Tibia
II with six tactile setae; tibia III with six tactile setae. Dorsal setae of
body slender and tapering, considerably longer than longitudinal inter¬
vals between bases. Aedeagus bent ventrad near middle of shaft, the
distal portion tapering and sigmoid. Length of body 280 p ; including
rostrum 360p .

b emale. — Similar to male. Terminal sensillum on palpus twice as
long as broad. Tibia I with nine tactile and one sensory setae; tarsus
I with five tactile and one sensory setae proximal to duplexes. Clunal
setae about two-thirds as long as outer sacrals. Genital flap and area
immediately anterior with transverse striae. Length of body 366 p ; in¬
cluding rostrum 433p; greatest width of body 253p.

Holotype. — Male, Leesburg, Florida, June 29, 1948 (R. A. Lafler),
on azalea; type no. 2177 in the 11. S. National Museum. P aratypes. —
Sixty-one females, 2 nymphs, Winter Garden, Florida, March 29, 1948

173

Subfamily l etrany chinae Rerlese

(0. D. Link), on blackberry; 3 males, 11 females, Leesburg, Florida,
June 29, 1948 (R. A. Lafler), on azalea; 13 females, Raleigh, North
Carolina, May 28, 1950 (C. F. Smith), on azalea; 19 females, Frost
Proof, Florida, April 20, 1951 (A. C. Baker), on passion flower; 8 fe¬
males, Baton Rouge, Louisiana, May 22, 1951 (L. D. Newsom), on
blackberry; 3 females, 1 larva, Corey, Louisiana, July 8, 1952 (J. S.
Roussel), on Rubus sp.

T il iarium Group

Members of the Tiliarium Group may be recognized by having eight
tactile setae on tibia II.

The species are, for the most part, very closely allied, and a lateral

174

Spider Mites

view of the aedeagus is usually necessary for identification. Differences
in the length of the dorsal setae, the terminal sensillum of the palpus,
the termination of the peritreme, the comparative length of components
of the duplex setae, and ventral striations of the opisthosoma are char-
acters sometimes useful for separation of the females on a local basis.

Eotetranychus muscicola ( Oudemans ), new combination
(Figures 129, 130)

Apotetranychus muscicola Oudemans, 1931, Ent. Ber., 8(178): 234;
Geijskes, 1939, Meded. Landbouwh. Wageningen, 42(4): 33.
Type : female, Arnhem, Holland, from moss; in the Rijksmuseum
van Natuurlijke, Leiden, Holland.

The female of muscicola differs from other members of the genus
Eotetranychus that have nine tactile and one sensory setae on tibia I
and eight tactile setae on tibia II by having only four tactile (and one
sensory) setae proximal to the duplexes on tarsus I, together with hav¬
ing the body broadly rounded with the dorsal setae somewhat shorter
than longitudinal intervals between them. The male is unknown.

This species has been known from a single female collected in
Holland, on moss. A number of females from Scotland (at Hoboken,
New Jersey quarantine, Perlmutter) were intercepted on Calluna sp.

Eotetranychus georgicus {Reck), new combination

Apotetranychus georgicus Reck, 1948, Trudy Zool. Inst. Akad. Nauk
Gruz. S.S.R., 8. Described from specimens from Georgia, S.S.R.,
on Rhamnus pallasii.

We have not seen the original description of Apotetranychus georgi¬
cus. However, the outstanding conception of tetranychid phylogeny,
which is expressed in the articles by Reck that we have been able to
see, indicates that he understands the basic principles of relationships
within the family. Reek’s keys (1950, 1952), indicate that his conception
of Apotetranychus is similar to that of Eotetranychus, and we, therefore,
make the new combination. Our own studies invalidate a distinction
between these related genera on a basis of dorsal tubercles on the
body, the shape of the dorsal setae, or the shape of the alveoli bearing
the dorsal setae.

175

Subfamily I e (rariy chinae Herlese

Fig. 134.

Eotetrany chus carpini borealis : dorsal aspect of female.

Eotetranychus perplexus (McGregor), new combi nat ion
(Figures 131, 132, 133)

Tetranychus perplexus McGregor, 1950, Anier. Midi. Nat., 44(2): 298.
Types : males and females, Lebec, California on Salix sp.; in
the U. S. National Museum.

The female of Eotetranychus perplexus agrees with most members of
the genus in that there are nine tactile and one sensory setae on tibia

176

Spider Mites

Fig. 135. Eotetranychus carpini: above, tibia and tarsus I of male E. carpini
borealis ; below, tibia and tarsus I of male, Hamden, Connecticut.

I and eight tactile setae on tibia II. However, it agrees with E. musci-
cola in that there are only four tactile (and one sensory) setae on tarsus
I proximal to the duplexes. In contradistinction to E. muscicola, the
body is slender, with the dorsal setae longer than the intervals between
them, and thus resembling most of the Tiliarium Group. Females are
sometimes found in association with Eotetranychus willamettei from

177

Subfamily /’ etrcuiychinae llerlese

Fig. 136. Eotetranychus carpini borealis : A.) aedeagus;

B.) peritreme; C.) palpus of female.

which they may be separated by having the peritreme bent or hooked,
not straight, dis tally.

The male may be readily recognized by having the aedeagus flaring
at the distal end to form a dorsal and a ventral angulation.

Collections, in addition to the types, that have been studied from
California are labelled: llatcreek (A. E. Pritchard), on Purshia triden-
tata; Modesto (A. E. Pritchard), on willow; Wasco and Bakersfield
(G. L. Smith), on willow; Tulare County H. Schweers), on willow;
Camp Nelson (E. W. Baker), on mountain mahogany; and Ridge Route,
Frenchman Flat (E. W. Baker), on willow. Other specimens studied are
from Satus Pass, Washington (E. J. Newcomer), on Prunus emarginatus;
Blewelt Pass, Washington (E. W. Baker), on Purshia sp.; and Basseaux

178

Spider Mites

Lake, British Columbia (E. VV. Baker), on Purshia sp. McGregor also
recorded this species from Idaho, and he further noted Cercocarpus
sp. as a host.

Eotetranychus tiliarium ( Hermann )

Trombidium tiliarium Hermann, 1804, Mem. Apt., p. 42. Described from
specimens from Straatsburg, France, on Tilia sp.

T etranychus tiliarium, Koch, 1838, Deu. Crust. Myr. Arach., 17: 13;
Hirst, 1920, Proc. Zool. Soc. Lond., 1920: 57; Hirst, 1924, Ann.
Mag. Nat. Hist (ser. 9), 14: 622; Oudemans, 1931, Ent. Ber.,
8(178): 235; Oudemans, 1937, Krit. Hist. Overz. Acar., 3(C): 1051.
T etranychus minimus Targioni Tozzetti, 1878, Ann. Agric., 1: 247.
Described from specimens from Italy, on Tilia Europaea. New
synonymy.

T etranychus telarius, Hirst, 1920, Proc. Zool. Soc. Lond., 1920: 57;
Oudemans, 1930, Ent. Ber., 8(175): 166. Zacher, 1921, Z. ang.
Ent., 7: 186. Oudemans, 1937, Krit. Hist. Overz. Acar., 3(C):
1045. Misidentification.

Eotetranychus telarius, Oudemans, 1931, Ent. Ber., 8(178): 225;
Geijskes, 1939, Meded. Landbouwh. Wageningen, 42(3): 31; Reck,
1948, Soobsch, Akad, Nauk Gruz. S.S.R. 8(9-10): 373. Misidentifi¬
cation.

The male of Eotetranychus tiliarium may be recognized by having
the aedeagus very long and slender, straight, and tapering to the tip.

The female bears nine tactile and one sensory setae on tibia I;
eight tactile setae on tibia II; and five tactile and one sensory setae
proximal to the duplexes on tarsus I. As in all other species having
this count of leg setae, the body is small and slender with long and
slender dorsal setae. As is usually the case with related species, the
end of the peritreme is hooked or angulate at the distal end (however,
Zacher describes a simple bulb).

Hermann (1804) may be considered the first reviser, inasmuch as
he proposed the specific name tiliarium for the linden mite and used
the# specific name telarius for the common spinning mite- of Europe.
It is true that Hermann was not entirely clear on his separation of the
two species. However, Koch (1838) restricted the specific name tiliarium
to the linden mite, and there appears to be little justification for sub¬
stitution of the Linnaean specific name telarius for this mite a£ proposed
by Oudemans (1931) and used by certain of his followers.

179

Subfamily I etrany chinae Herlese

lhe synonymy of minimus with tiliarium is based primarily on the
host and the figure of the leg and empodium that was presented by
1 argioni Tozzetti.

Specimens studied are from Germany, on I ilia sp., kindly submitted
by h . Zacher. Other authentic records are all from Europe on trees
such as maple, sycamore, horse-chestnut, hawthorne, hazel, and willow.
A collection too recent to be included in the key was made from 7 ilia
sp., July 9-19, Amherst, Massachusetts (W, B. Becker).

Eotetranychus carpini ( Oudemans )

(Figures 134, 135, 136)

Tetranychus carpini Oudemans, 1905, Tijd. Ent., 48: LXXIX; Oudemans,
1910; Bui. Ent. Res., 1: 114; Oudemans, 1915, Arch. Naturg.,
81 (5): 44; Hirst, 1920, Proc. Zool. Soc. Lond., 1920 : 56; Zacher,
1921, Z. ang. Ent., 7: 185. Type: male, Beuel, near Bonn, Hol¬
land, on Carpinus betulus; represented only by a figure in the
Rijksmuseum van Natuurlijke Historie, Leiden, Holland.

Eotetranychus carpini, Oudemans; 1931, Ent. Ber., 8(131): 290; Geijskes,
1939, Meded. Landbouwh. Wageningen, 42(4): 32.

Tetranychus borealis Ewing, 1913, Ann. Ent. Soc. Amer., 6: 457;
McGregor, 1919, Proc. U. S. Natl. Mus., 56(2303): 658; McGregor,
1950, Amer. Midi. Nat., 44(2): 306. Types : males and females,
from the Coast Range Mountains, Benton County, Oregon; on
Spiraea sp.; in the U. S. National Museum.

Eotetranychus carpini borealis, Pritchard and Baker, 1952, Hilgardia,
21(9): 261.

Tetranychus flavus Ewing, 1913, Ann. Ent. Soc. -Amer., 6:458; McGregor,
1909, Proc. U. S. Natl. Mus., 56(2303): 654; McGregor, 1950,

Amer. Midi. Nat., 44(2): 286. Types: males and females, Hood

River, Oregon, on apple; in the U. S. National Museum.

Tetranychus oregonensis McGregor, 1917, Proc. U. S. Natl. Mus.,

51(2167): 585; McGregor, 1919, Proc. 1. S. Natl. Mus., 56(2303):
661; McGregor, 1950, Amer. Midi. Nat., 44(2): 295. Types: males
and females, Portland, Oregon, on wild cherry: in the U. S. National
Museum.

Tetranychus monticolus McGregor, 1917, Proc. U. S. Natl. Mus.,

51(2167): 584; McGregor, 1919, Proc. U. S. Natl. Mus., 56(2303):
662; McGregor, 1950, Amer. Midi. Nat., 44(2): 293. Types: males
and females, Mount Hood, Oregon, on I accinium sp.

180

Spider Mites

Fig. 137. Eotetranychus coryli: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

181

Subfamily Tetranychinae Rerlese

Fig. 138. Eotetranychus coryli: aedeagus.

(Tetranychus willamettei, Garman, 1940, Bui. Conn. Agr. Exp. Sta.,

(431: 85. Misidentification.

Schizotetranychus ( Eotetranychus ) carpinula Reck, 1950, Trudy Inst.
Zool. Akad. Nauk Gruz. S.S.R., 9: 131. Described from male and
female, Gori and Lagodekhi, Georgia, S.S. R., on Carpinus betulus.
New synonymy.

( Schizotetranychus ( Eotetranychus ) pterocaryae Reck, 1950, Trudy Inst.

Zool. Akad. Nauk Gruz. S.S. R., 9: 130. Described from male and
female, Lagodekhi, Georgia, S.S.R., on P terocarya fraxinifolia.
New synonymy.

The peritremes of both carpinula and pterocaryae end in a simple
bulb, and only the comparative size of the bulb was used to differentiate
the two species. The other synonymy is based on the studies of
Pritchard and Baker (1952).

The males of Eotetranychus carpini, E. willamettei , and E. coryli,
E. aesculi, E. viticola, E. uncatus, and E. pruni, form a complex in
which each of the species has an aedeagus that is very long and slender,
acutely tapering, and strongly undulate near the middle. Both sexes
of E. carpini differ from E. willamettei by having the proximal member
of each duplex very short in comparison with the distal member; and
from the other species by having the distal end of the peritreme forming
a simple bulb (not a fork as illustrated by Oudemans, 1915).

Males studied from England, on Carpinus betulus, have only one
or two sensory setae (in addition to the nine tactile setae) on tibia I;
whereas there are four sensory setae on tibia I of the males studied
from the northwestern United States. Because of this discrepancy,

182

Spider Mites

Fig. 139. Eotetranychus coryli: A.) terminations of the peritreme of speci¬
mens from Washington, D. C.; B.) terminal segment of the palpus of female;
C.) terminal segment of male palpus; D.) appendages of tarsus 1 of female;
E.) appendages of tarsus 1 of male.

Pritchard and Baker (1952) referred to the European form as Eotetrany¬
chus carpini carpini and that from the western United States as E.
carpini borealis.

A third possible subspecies, or else a variation, occurs in the north¬
eastern United States. Specimens from Hamden, Connecticut (Philip

183

Subfamily 1 etranychinae Herlese

Garman), on beech, differ from the two named forms in that tibia I of
the male possesses three sensory setae, being intermediate between
previously examined specimens.

Eotetranychus carpini carjjini is recorded from Germany and England,
on hornbean, hazel nut, willow, maple, and alder.

Eotetranychus carpini borealis is known from British Columbia,
Canada, to central California, where it is often a pest of apples and
pears. Other hosts include cherry, raspberry, blueberry, spirea, alder,
and willow.

Eotetranychus co ryli [Reck), new combination
(Figures 137, 138, 139)

Schi eotetranychus [Eotetranychus) coryli Reck, 1950, Trudy Inst. Zool.
Akad. Nauk Gruz. S.S. R., 9: 130. Described from males and
females, Staliniry, Gori, Telavi, and Lagodekhi, Georgia, S.S.R.,
on Corylus avellana.

The original description and figures of coryli indicate that this
species differs from other members of the carpini complex in that the
distal end of the peritreme is simply bent, d he terminal sensillum of
the palpus of the female is slender, about three times as long as broad.

Specimens examined from Washington, D. C., (E. W. Baker), on
red maple, are tentatively referred to this species.

Eotetranychus uncatus Garman
(Figure 3)

Eotetranychus uncatus Garman, 1952, in Pritchard and Baker, Hilgardia,
21(9): 263. Holotype: male, Amherst, Massachusetts, on apple;
in the collection of the Connecticut Agricultural Experiment
Station.

Eotetranychus uncatus is closely allied to E. carpini from which it
differs only in having the distal end of the peritreme strongly T-shaped.
Many specimens studied have shown no variation in this character.
The terminal sensillum of the female palpus is two and one-half times
as long as broad.

This species has recently been recognized as a serious pest of
apples in Massachusetts and Connecticut. The only other specimens
studied that are similar are from Utah, on white birch.

Spider Mites

Fig. 140. Eotetrany chus willamettei : palpus of female
and tarsus I of female.

Eotetrarrychus aesculi {Reck), new combination

Schizotetranychus {Eotetrany chus) aesculi Reck, 1950, Trudy Inst.
Zool. Akad. Nauk Gruz. S.S.R., 9: 128. Described front males
and females, Tiflis, Georgia, S.S.R., on street plantings of
Aesculus hippocastanum and Acer platanoides.

Reek’s description and figures of aesculi indicate that this may
be a prior name for Eotetrany chus uncatus, the peritreme being IJ-shaped
distally. However, the terminal sensillum of the female palpus, as
described and figured by Reck, is somewhat slenderer and narrows
proximally.

185

Su

bfamily Tetranychinue lierlese

Fig. 141. Eotetranychus populi- A.) tibia and tarsus 1 of female; R.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

186

Spider Mites

Fig. 142. Eotetranychus populi: A.) appendages of tarsus I of male; B.)
empodium of tarsus IV of male; C.) appendages of tarsus II of male; D.) append¬
ages of tarsus I of female.

Eotetranychus viticola (Reck), new combination

Schizotetrany chus ( Eotetranychus ) viticola Reck, 1948, Soobsh. Akad.
Nauk Gruz. S.S.R., 9(6); 374; 9(7): 446, 447. Described from
specimens from Georgia, S.S.R., on grape.

The long, slender, tapering, undulate aedeagus places this species
in the carpini complex; although the terminal sensillum is slender as in
E. willamettei, the peritremes are hooked distally.

Eotetranychus pruni ( Oudemans )

Tetranychus pruni Oudemans, 1931, Ent. Ber., 8(177): 195. Type : female,
Germany, on Prunus domestica; possibly in the Rijksmuseum
van Natuurlijke Histone, Leiden, Holland.

Eotetranychus pruni, Geijskes, 1939, Meded. Landbouwh. Wageningen,
42(4): 31.

Schizotetranychus ( Eotetranychus ) pruni. Reck, 1950, Trudy Inst. Zool.
Akad. Nauk Gruz. S.S. R., 9: 129.

Oudemans original description of pruni, on the basis of a single
female collected in Germany in 1884, on Prunus sp. indicates that this
species differs from carpini in that the end of the peritreme is “gebogen”

187

Subfamily T etrany chinae Herlese

or I -shaped. Heck (1950) found a similar mite on Erurius spp. in Georgia,
S.S. R., and f^ave a more ample description of both sexes. Heck’s mites
resemble Eotetranychus uncatus closely, except that the terminal sen-
sillum of the female palpus is very slender, four times as long as broad.

Eotetranychus w ; / lamettei ( McGregor )

(Figure 140)

7 etranychus willamettei McGregor, 1917, Proc. U. S. Natl. Mus.,
51(2167): 586; McGregor, 1919, Proc. U. S. Natl. Mus., 56(2303):
660; Types : males and females, Oregon City, Oregon, on Quercus
garryana4, in the P. S. National Museum.

Eotetranychus willamettei, Pritchard and Baker, 1952, Hilgardia, 21(9):
263.

Fig. 143. Eotetranychus populi :
aedeagus, Connecticut.

Both sexes of Eotetranychus
willamettei differ from other species
in the genus by having each member
of the pair of duplex setae on tarsus
II nearly equal in length. The female
further differs from Eotetranychus
carpini and E. uncatus by having
the distal sensillum on the palpus
about four times as long as broad.
The peritreme is straight distally,
ending in a simple bulb. The
aedeagus resembles that of Eotet¬
ranychus carpini and E. uncatus,
being long and slender, tapering
and with a strong undulation. Tibia
I of the male bears four sensory
setae.

This species is known from
southern California to Washington
State. It is a serious pest of grapes
in California and occasionally in¬
fests apple. Other hosts include
antelope brush, box elder, service
berry, and oak.

188

Spider Mites

Fig. 144. Eotetranychus weldoni: A.) tibia and tarsus I of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of male.

Eotetranychus populi (Koch)
(Figures 141, 142, 143)

189

Subfamily T etrany chinae Berlese

l etranychus populi Koch, 1838, Deut. Crust. Myr. Arach., 17: 14;
Oudenmns, 1937, Krit. Hist. Overz. Acar., 3(C): 1041; Hirst,
1930, Proc. Zool. Soc. Lend., 1920 : 52; Carman, 1923, Bui.
Conn. Agr. Expt. Sta., 247: 339; Oudemans, 1931, E nt. Ber.,
8(178): 235; Oudemans, 1939, Krit. Hist. Overz. Acar., 3(C):
1041; Carman, 1940, Bui. Conn. Agr. Expt. Sta., 431: 85;
McGregor, 19-10, Amer. Midi. Nat., 44(2): 301. Described from
specimens from Regensburg, Germany, on poplar.

T etranychus salicicola Zacher, 1920, Vorlauf. Diag. ein. neu. Spinn-
milb., p. 1; Zacher, 1921, Zts. angew. Ent., 7: 186. Types :
males and females, Berlin-Dahlem, Germany, on willow and
poplar. Possibly in the Zacher collection. New synonymy.
Amphitetranychus salicicola, Geijskes, 1939, Meded. Landbouwh.
Wageningen, 42(4): 41.

Schizotetranychus ( Eotetranychus ) salicicola, Reck, 1948, Soobsh,
Akad. Nauk. Cruz. S.S.R., 9(7):374.

Both sexes of Eotetranychus populi
may be differentiated from other
members of the genus by having the
distal end of the peritreme forming
an irregular, anastomosing enlarge¬
ment, together with having the dorsal
setae of the body longer than the
intervals between them.

The aedeagus is very long and slender, as in Eotetranychus tili-
arium and the E. carpini complex, but it is slightly undulate and less
tapering, being rounded at the tip.

Hirst (1920) showed that specimens from England, on poplar, and
identified as populi, have an aedeagus similar to that of species often
occurring on poplars in North America, and Zacher’s description of
salicicola indicates that of a similar aedeagus with clarification of
the complex termination of the peritreme. Garman’s (1940) identifica¬
tion of populi is, therefore, accepted.

This species is recorded from Germany and England, as well as
Georgia, S.S.R., on poplar and willow. It also occurs in the eastern
United States on the same hosts. Specimens examined are from Hamden,
Connecticut (Philip Carman), on poplar; Farmingdale, New ^ ork
(J. G. Matthvsse) , on aspen; and Durham, North Carolina (A. E. Pritchard),
on weeping willow.

Fig. 145. Eotetranychus weldoni-
aedeagus, California.

190

Spider Mites

Fig. 146. Eotetranychus malvastris: A.) tibia and tarsus I of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of male.

191

Subfamily I etranychinue Berlese

Fig. 147. Eotetranychus malvastris: A.) appendages of tarsus I of female;
B.) appendages of tarsus I of male; C.) palpus of male.

Eotetranychus weldoni {Ewing), new combination
(Figures 144, 145)

Tetranychus weldoni Ewing, 1913, Ann. Ent. Soc. Amer., 6: 457;
McGregor, 1919, Proc. U. S. Natl. Mus., 56(2303): 660; McGregor,
1950, Amer. Midi. Nat., 44(2): 305. Types: males and females,
Grand Junction, Colorado, on cottonwood and possibly other
hosts; in the U. S. National Museum.

Tetranychus californicus McGregor, 1928, Proc. Ent. Soc. Wash., 30:
11; McGregor, 1950, Amer. Midi. Nat., 44: 282. Types: males
and females, Porterville, California, on Populus sp.; in the U. S.
National Museum. New synonymy.

Eotetranychus weldoni differs from E. populi only in that the distal
end of the peritreme forms a simple, long hook rather than being anas¬
tomosing. The two names represent allopatric species or subspecies.

This species is known from the midwestern and western Lnited States
on poplar and willow. Aside from the types of weldoni and californicus ,
specimens have been studied from Great Bend, Kansas (R. E. Beer), on
poplar; Wildwood, Wyoming (G. F. Knowlton), on willow; Shafter, Cali¬
fornia (G. L. Smith), on poplar; Arvin, California (A. E. Pritchard),
on poplar; and San Joaquin, California (G. I .. Smith), on willow.

192

Spider Mites

Eotetranychus malvastris (McGreyor), new combination
(Figures 146, 147, 148)

Tetranychus malvastris McGregor, 1950, Amer. Midi. Nat., 44(2): 290.
Types: males and females, Whittier, California, on Malvastrum
sp.; in the U. S. National Museum.

The aedeagus of Eotetranychus
malvastris is distinctive in being
triangular with the ventral margin
practically straight and the dorsal
margin gradually narrowing to an
acute tip. Females are not readily
differentiated from several other
members of the Tiliarium Group.

Specimens are known only from
southern California and Arizona.
Types of malvastris are from Whittier,
California, on Malvastrum sp. and
McGregor recorded specimens from
Gila Bend, Arizona, on the same
host. In addition to the types of
malvastris, we have studied speci¬
mens from Aguanga, California, (A.
E. Pritchard), on Adenostema fasci-
culatum; and Barrett, California (A.
E. Pritchard), on Malva sp.

Fig. 148. Eotetranychus malvastris :
aedeagus, California.

Eotetranychus smithi Pritchard and Baker, new species
(Figures 149, 150)

The male of Eotetranychus smithi may be recognized by having the
proximal half of the aedeagus with the ventral margin directed some¬
what dorsad, and with the distal portion abruptly narrowed to form a
fine, caudally directed stylet.

The female resembles that of Eotetranychus hicoriae in that there
are longitudinal striae anterior to, but not on, the genital flap, and
the peritreme is strongly hooked at its distal end. The terminal sen-
sillum on the palpus, however, is stouter than that in the female of E.
hicoriae, being about one and one half times as long as wide proximally.

193

Subfamily Tetranychinae Herlese

Fig. 149. Eotetranyct.us smithi : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

194

Spider Mites

Fig. 150. Eotetranychus smithi : aedeagus and terminal
segment of palpus of male.

Fig. 151. Eotetranychus yumensis:
aedeagus, type.

This species is known only from
the northeastern United States on
rose and bramble.

Male. — Terminal sensillum of pal¬
pus about three times as long as broad
at base. Peritreme strongly retrorse at
distal end. Tarsus 1 with four tactile
and three sensory setae proximal to
the duplexes; empodium I with three
pairs of very slender digits, the dorsal
pair being the finest. Tibia II with
eight tactile setae; tibia III with six
tactile setae. Body with dorsal setae
slender, much longer than longitudinal
intervals between them. Aedeagus
with proximal portion of shaft curved
dorsad, the median portion abruptly
narrowed, and the distal portion very
slender, tapering, caudally directed
but slightly undulate. Length of body
230p ; including rostrum 320 p.

195

Subfamily 1 etrany chinae llerlese

Fig. 152. Eotetranychus frosti: A.) tibia and tarsus 1 of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

196

Spider Mites

Fig. 153. Eotetranychus frosti : A.) terminal segment of palpus of male; B.)
terminal segment of palpus of female; C.) appendages of tarsus I of male; D.)
appendages of tarsus I of female.

Female. — Similar. Terminal sensillum of palpus about one and one
half times as long as wide as base. Tibia I with nine tactile and one
sensory setae; tarsus I with four tactile and one sensory setae proximal
to duplexes. Area immediately anterior to genital flap with longitudinal
striae; genital flap with transverse striae. Length of body 280 p; greatest
w idth of body 385 p .

l/olotype. — Male, College Park, Maryland, June 22, 1951 (Floyd
F. Smith), on rambler rose; type no. 2178 in the U. S. National Museum.
P aratypes. — Four males, 2 females, 2 nymphs, College Park, Maryland,
June 22, 1951 (Floyd b. Smith) on rambler rose; 1 male, Tyson’s Corner,
Virginia, July 11, 1951 (F. \\. Baker), on Rubus phoenicolasius.

Ihis species is named in honor of Floyd F. Smith who collected
part of the type series and who has made major contributions toward
control of the two-spotted spider mite in greenhouses.

197

Subfamily T etrany chinat Rerlese

Fig. 154. Eotetranychus frosti : A.) aedeagi of types;
B.) aedeagi of specimens from Missouri.

198

Spider Mites

Kip. 155. Eotctrunychus sexmaculatus : A.) tibia and tarsus I of female; B.)
tibia and tarsus 1 of male; C.) appendages of tarsus I of female; D.) appendages
of tarsus I of male.

199

S

ubfamily I etranychinae Herlese

Eotetranychus yumensis (McGregor), new combination
(Figure 151)

Tetranychus yumensis McGregor, 1934, Proc. Fnt. Soc. Wash., 36: 256;
McGregor, 1950, Amer. Midi. Nat., 44(2): 304. Types: males and
females, Yuma, Arizona, on citrus; in the U. S. National Museum.

The aedeagus of yumensis differs from other species of Eotetranychus
in that it forms a shallow, nearly sigmoid dorsal curve, the distal end
tapering gradually to a caudally directed point. The female resembles
several other members of the Tiliarium Group having transverse striae
anterior to the genital flap.

This species, originally known from Yuma, Arizona, has recently
become rather abundant in the Coachella and Imperial Vallies of Cali¬
fornia, particularly on lemon and tangerine. Grapefruit and orange also
serves as hosts. L. R. Jeppson and Andrew Deal sent us most of the
specimens studied from California citrus.

Eotetranychus frosti [McGregor), new combination
(Figures 152, 153, 154)

Tetranychus frosti McGregor, 1952, Proc. Fnt. Soc. Wash., 54: 142.
Types : males and females, lempe, Arizona, on rose; in the l . S.
National Museum.

The male of Eotetranychus frosti may be recognized by having the
aedeagus sharply bent dorsad to form a slender, sigmoid, distal end.
Females are similar to several others of the Tiliarium Group that bear
transverse striae anterior to the genital flap.

200

Spider Mites

Types from Tempe, Arizona, on rose, have been studied as well
as specimens collected near Modesto, California, August 8, 1949 (A. E.
Pritchard), on blackberry.

Additional specimens referred to this species are from Louisiana,
Missouri, August 12, 1952 (D. W. Hamilton), on raspberry; and Valley
City, North Dakota (V. Goodfellow), on raspberry. In males from these
collections, the aedeagus bends somewhat more sharply dorsad and the
bent portion is somewhat stouter. Moreover, the terminal sensillum on
the palpus of the male is more conical.

Eotetranychus hirsti Pritchard and Baker, new name

Tetranychus fici Hirst, 1926 (not Murray, 1877) Proc. Zool. Soc. Lond.,
1926: 828; Rahman and Sapra, 1940, Proc. Indian Acad. Sci.
(ser. B), 11: 186. Types : males and females, Coimbatore, India,
on fig ( Ficus carica); probably in the British Museum (Natural
History). Primary homonym.

This species, known only from South India, on fig leaves and fruit,
is very closely related to Eotetranychus frosti McGregor. The aedeagus
bends dorsad, with the upturned portion slender, tapering, and sigmoid.
The aedeagal bend, as figured by Hirst, is constricted; whereas it is
not in McGregor’s species.

Murray regarded his fig mite, from near London, England, to be an
introduced species. However, his description of the female as being
ovate is not characteristic of most species of Eotetranychus ; and it
is likely that Murray was dealing with an infestation of the two-spotted
spider mite, a species that is known to occur on fig.

Eotetranychus suginamensis ( Yokoyama ), new combination

Tetranychus suginamensis Yokoyama, 1922, Bui. Imp. Seric. Exp.
Sta. Japan, 8(6): 282. Described from specimens from Japan,
on mulberry.

Tetranychus mori Rahman and Sapra, 1940, Proc. Indian Acad. Sci.
(ser. B), 11: 184. Types: males and females, Lyallpur, India,
on mulberry ( Morus alba). New synonymy.

Yokoyama’s description of the mites as forming small colonies on
the underside of the leaf, the hibernation of adults, and the pearly

201

Subfamily T etranychinae Berlese

c

Fig. 157. Eotetranychus leuisi : A.) tibia and tarsus I of female; R.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; 0.) tibia and tarsus II
of male.

202

Spider Mites

Fig. 158. Eotetranychus lewisi: above, empodium I of
female; below, empodium I of male.

egg with a dorsal stipe all indicate that this is a species of Eotetrany¬
chus. The aedeagus was described as having a short shaft, tapering
and bending distally to form a small hook.

The description and figure of the aedeagus of Tetranychus mori is
similar to that of T. suginamensis, the aedeagus being tapering, strongly
curved dorsad and with the tip directed anteriorly. Both are from the
same host, mulberry. Mori is, therefore, considered to be a synonym of
suginamensis. We have not seen this species.

Eotetranychus sexmaculatus {Riley), new combination
(Figures 155, 156)

Tetranychus 6-rnaculatus Hi ley, 1890, Insect life, 2: 225. Described
from specimens from Florida, on citrus.

Tetranychus sexmaculatus. Banks, 1900, U. S. Dept. Agr. Div. Ent.
lech. Ser., 8: 75; McGregor, 1919, Proc. U. S. Natl. Mus.,
56(2303): 659; McGregor, 1950, Amer. Midi. Nat., 44: 301;
Ebeling, 1950, Subt. Ent., p. 374. Emendation.

203

Subfamily I etrany chinae Berlrse

The aedeagus of Eotetranychus sexmaculatus is distinctive in that
it curves slightly dorsad near the middle of the shaft; but the distal
portion is caudoventrally directed, and the tip bears a diagnostic, some¬
what ventrally deflexed hook.

The female is distinctive in having longitudinal striae on the genital
flap.

This species has long been known as a serious pest of citrus in
Florida and southern California, and more recently it has become an
important pest of avocado in California. The mites are found primarily
on the foliage, forming restricted colonies under the leaves.

California specimens studied by us are from Berkeley, (A. E.

204

Spider Mites

Fig. 160, Eotetranychus deflexus : A.) tibia and tarsus I of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of male.

205

Subfamily Tetrany chinae Berlese

Fig. 161 .Eotetranychus
deflexus : terminal seg¬
ment of male palpus.

Pritchard) on elaeagnus, royal paulonia, pyra-
cantha, azalea, camphor, and maple; Palo Alto
(A. E. Pritchard), on camphor; Ventura (L. R.
Jeppson), on lemon; Capistrano (L. R. Jeppson),
on citrus; Orange (C. A. Fleschner), on citrus;
and Costa Mesa (M. Badgley), on citrus, Florida
collections are from Ojus (0. D. Link) , on citrus;
Eloise Loop (L. C. Enorr), on citrus, and Lake
Alfred (L. C. Knorr), on citrus. Additional mate¬
rial has been studied from Formosa (T. C. Mao),
on Citrus grandis.

Eotetranychus talisiae (Hirst), new combi nation

Tetrany chus talisiae Hirst, 1920, Proc. Zool. Soc. Lond. 1920 : 54; Me
Gregor, 1950, Amer. Midi. Nat., 44(2): 302. Types: males and
females, from tropical greenhouse, Kew Gardens, England, on
Talisia princeps; in the British Museum (Natural History).

Eotetranychus talisiae is related to E. sexmaculatus in that the area
immediately anterior to the genital flap in the female has longitudinal
striae, as does the anterior portion of the flap. Talisiae may be dif¬
ferentiated from sexmaculatus in that each empodium of the female
possesses a small, well defined dorsal spur which is lacking in sex¬
maculatus. The aedeagus of talisiae is similar to that of yumensis , being
straight distally and without the ventrally deflexed hook found in sex¬
maculatus.

Eotetranychus lewisi (McGregor), new combination
(Figures 157, 158, 159)

T etranychus lewisi McGregor, 1943, Proc. Ent. Soc. Wash., 45: 12<;
McGregor, 1950, Amer. Midi. Nat., 44(2): 288; Ebeling, 1950,
Subt. Ent., p. 376. Types: males and females, Corona, California,
on orange; in the U. S. National Museum.

The aedeagus of Eotetranychus lewisi is distinctive by being grad¬
ually tapering and by forming a broad, sigmoid, ventral bend. The
peritreme is strongly hooked or angulate distally. Tibia 1 of the male

206

Spider Mites

usually bears three sensory setae (in addition to the nine tactile setae),
but rarely only two sensory setae are present.

The Lewis spider mite is found primarily along the California coast.
It is a pest of citrus, having been noted primarily on the fruit, causing
a silvering on lemons and a russetting of oranges. McGregor recorded
this species from southern California, on orange, lemon, bur-clover,
and castor-bean. Other than the types, collections studied by us are
from Palo Alto, California (A. E. Pritchard), on Ceanothus sp.; and
Santa Paula, California (C. A. Fleschner), on castor bean and olive.

Eotetranychus deflexus (McGregor), new combination
(Figures 160, 161, 162)

7 ctranychus deflexus McGregor, 1950, Amer. Midi. Nat., 44(2): 284.
I ypes: males and females, Grant’s Pass, Oregon, on Symphori-
carpos sp.; in the U. S. National Museum.

207

Subfamily I etrany chinae Herlese

Fig. 163. Eotetrany chus eccli sis: A.) tibia and tarsus I of female; 0.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

208

Spider Mites

Fig. 164. Eotetrany chus ecclisis : A.) empodium I of male; B.) empodiuin
II of male; C.) terminal segment of palpus of female; D.) terminal segment of
palpus of male.

Schizotetranychus cercocarpi McGregor, 1950, Anier. Midi. Nat., 44(2):
308. Types : males and females, Camp Nelson, California, on
Cercocarpus sp.; in the U. S. National Museum. A rew synonymy.

The male of Eotetranychus deflexus may be recognized by having
the aedeagus strongly bent ventrad near the middle with the bent portion
tapering and sigmoid, together with having the distal segment of the
palpus provided with a rudimentary terminal sensillum. The mediodorsal,
tapering sensilla of the last palpal segment of the male are subequal
in length. The peritreme is straight distally, terminating in a simple
bulb, and the striae on the genital flap of the female and the area
immediately anterior is transverse.

This species is known only from Oregon, and California. A new
collection is from The Dalles, Oregon (E. W. Baker), on snowberry.

209

Subfamily Tetranychinae Hrrlese

Fig. 166. Eotetranychus pcdlidus : A.) tibia and tarsus I of female; P.l

tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of male.

210

Spider Mites

Fig. 167. Eotetranychus pallidus : peritremes and aedeagus.

Eotetranychus ecclisis Pritchard and Baker, new species
(Figures 163, 164, 165)

Eotetranychus ecclisis is closely allied to E. deflexus in that the
terminal sensillum on the male palpus is rudimentary and the aedeagus
is ventrally bent to form a sigmoid curve. However, the tapering sensilla
on the male palpus are strongly dissimilar in length, and the aedeagus
is slightly widened at the ventral bend. Moreover, the female has longi¬
tudinal striae immediately anterior to the genital flap.

This species is known only from southern Mexico, on, Artemisia
mexicana.

Male. — Terminal segment of palpus with distal sensillum rudimentary;
mediodorsal, tapering sensilla with one member strongly developed,
twice as long as the other and nearly four times as long as proximodorsal
fusiform peg. Peritreme straight distally, ending in a single chambered
bulb. Tibia I with nine tactile and three sensory setae; tarsus I with
four tactile and two sensory setae proximal to duplexes; empodium I
bifid with a small mediodorsal tooth, each side being composed of three
short teeth. Tibia I with eight tactile setae; tibia III with six tactile
setae. Body with dorsal setae slender and tapering, considerably longer
than longitudinal intervals between them. Aedeagus with distal one-
half bent ventrad and sigmoid, the ventral bend somewhat widened and
the distal end caudally directed. Length of body 293 g ; including
rostrum 400 g.

Female. — Similar. Terminal sensillum of palpus about twice as long
as wide at base. Tibia I with nine tactile and one sensory setae; tarsus

211

Subfamily 1 etranychinae Berlese

I with five tactile setae posterior to duplexes. Genital flap with trans¬
verse striae; iirea immediately anterior to genital flap with longitudinal
striae. Length of body 330(1; greatest width of body 460 fi.

Holotype. — Male, Mexico City — Cuernavaca Highway, kilometer 67,
January 22, 1941 (E. W. Baker), on Artemisia mexicana ; tvpe no. 2179
in the l . S. National Museum. P aratypes. — One male, 7 females, Mexico
City — Cuernavaca Highway kilometer 67, January 22, 1941 (E, U. Baker),
on Artemisia mexicana.

Eotetranychus pallidus ( Garman ), new combination

(Figures 166, 167)

Tetranychus pallidus Garman, 1940, Bui. Conn. Expt. Sta., 431: 86;
McGregor, Amer. Midi. Nat., 44(2): 297. 7 \pes: males, females,
nymphs, larvae, and eggs, Hamden and Southington, Connecticut,
on beech; in the collection of the Connecticut Agricultural
Experiment Station.

Males referred to Eotetranychus pallidus may be readily recognized
by having the aedeagus bent sharply ventrad near the middle, the shaft
being abruptly constricted just before the bend. The distal portion of
the aedeagus is tapering and strongly sigmoid.

Ihe female is distinctive in that the striae of the integument im¬
mediately anterior to the genital flap are irregular, rather than being
transversely or longitudinally parallel. This area of irregular striae
is not as broad as in those species with longitudinal striae.

The peritreme is straight distally or with a terminal, but simple
angulation. Dorsal setae on the body are but slightly longer than the
longitudinal intervals between them.

This species has been known only from New Haven, Co nnecticut,
on beech. Type material has been studied by us, as well as specimens
from Cromwell, Connecticut, June 21, 1950 (P. Garman), on alder.

Eotetranychus hicoriae (McGregor), new combination
(Figure 168)

Tetranychus hicoriae McGregor, 1950, Amer. Midi. Nat., 44(2): 287.
Types: males and females, biggins, Mississippi, on pecan;
in the U. S. National Museum.

212

Spider Mites

Fig. 168: Eotetranychus hicoriae:
peritreme and aedeagus.

The aedeagus of Eotetranychus hicoriae closely resembles that of
E. pallidus in that it is bent very sharply ventrad with the bent portion
strongly sigmoid. However, the shaft of the aedeagus gradually narrows
to the bend.

The peritreme is strongly hooked distally;and the dorsal setae of the
body are much longer than the longitudinal intervals between them.

The female is similar to Eotetranychus smithi and E. ecclisis in that
the integumentary striations immediately anterior to the genital flap are
longitudinal. The genital flap bears transverse striae.

Ihe species is common in the southeastern United States, and
Pierce (1953) reported serious infestations on pecan scattered through¬
out northern Louisiana.

Specimens studied by us, in addition to the types, are from Durham,
North Carolina (A. E. Pritchard), on hickory, horse chestnut and black¬
jack oak; Glendale, Maryland (E. Van Leeuwen), on Asiatic and
European chestnut; Ithaca, New York (J. G. Matthysse), on red oak;
and many specimens from Georgia, on pecan.

Eotetranychus fagi ( Zacher)j new combination

Epitetranychus fagi Zacher, 1922, Verb. Deut. Gesel. ang. Ent., 5: 6;
Zacher, 1932, Zoo. Anz., 97(7)8: 181; Zacher, 1933, Mitt. Zool.
Mus. Berlin, 19: 587. Types: probably males and females, on
Eagus silvatica ; possibly in the Zacher collection.

213

Subfamily Tetranychinae Herlese

Schizotetranychus (Eotetranychus) fagit Heck, 1950, Trudy Inst. Zool.
\kad. Nuuk Gruz. S.S. K., 9: 131.

lhe illustration ol the aedeugus that was presented bv Zacher
(1932) indicates that this species may be recognized by having the
aedeugus bent sharply ventrad, the bent portion straight and broadly
tapering to a point. However, Heck (1950) illustrates the aedeugus as
being sharply bent dorsad and narrowly tapering to a point. The peri-
treme is straight distally, ending in a small bulb.

Zacher indicates that this is a common species in Germany, on
European beech, and Heck recorded specimens from Georgia, S.S. H.
on beech.

Eotetranychus jungiae Oudemans

Eotetranychus jungiae Oudemans, 1931, Ent. Her., 8(178): 225; Geijskes,
1939, Meded. Landbouwh. Wageningen, 42(4): 32. Type: female,
Triesdorf, Germany, on Salvia (= Jungia) splendens; possibly
in the Zacher collection.

This species was described on the basis of a single female, found
in association with cotypes of T etranychus ludeni Zacher (in Europe),
and supposedly originating from Brazil. Oudemans’ description of the
female indicates only that it is similar to females of Eotetranychus
tiliarium and E. carpini, but the terminal sensillum of the palpus was
described as being very small and lancet-like.

Eotetranychus aurantii ( Targioni Tozzetti), new combination

T etranychus aurantii Targioni Tozzetti, 1878, Ann. Agric., 1: 253,
fig. 4a. Described from females (probably Florence) Italy, on
live oak.

7 etranychus quercinps Berlese, 1886, Acari Dann. I’iante Goltivate,
p. 23. Based on the description of Targioni Tozzetti ( 18 < 8) of
mites from Italy, on oak. New synonymy.

Targioni Tozzetti referred in his text (p. 253) to this mite as “Tet-
rcmico della Erinosi del Leccio,” apparently not intending to give
it a scientific name. However, in his legend to the figures of this
species, the name T etranychus aurantii is validated. The figures of
the tarsal appendages indicate that there are three pairs of empodial
hairs.

214

Spider Mites

Topotype material must be
species can be determined.

studied before the true status of this

Eotetranychus aceri (Reck), new combination

Schizotetranychus ( Eotetranychus ) aceri Reck, 1948, Soobsh. Akad.
Nauk Cruz. S.S.R., 9(6): 373: 9(7): 446. Described from specimens
from Tiflis, Georgia, S.S.R., on Acer negundo.

This species is very similar to E. coryli and may prove to be the
same. The peritreme ends distally in a simple bulb which is bent weakly
posteriorly.

Eotetranychus bakuriensi s (Reck), new combination

Schizotetranychus ( Eotetranychus ) bahuriensis Reck, 1948, Soobsh. Akad.
Nauk Gruz. S.S.R., 9(6): 374; 9(7): 448. Described from specimens
from Bakuriani, Georgia, S.S.R., on Alchimilla erythropoda.

Reek’s figure of the aedeagus, although showing it bending dorsally
rather than ventrally, indicates a relationship with E. deflexus and E.
ecclisis. The peritreme ends distally in a simple bulb which is bent
weakly posteriorly.

Eotetranychus fraxini (Reck), new combination

Schizotetranychus ( Eotetranychus ) fraxini Reck, 1948, Soobsh. Akad.
Nauk Gruz. S.S.R., 9(6): 374; 9(7): 448, 449. Described from
specimens from Georgia, S.S.R., on Fraxinus spp.

The aedeagus is short, gently sigmoid, somewhat similar to that of
E. lewisi. The peritreme ends in a simple bulb.

Eotetranychus rubiphilus (Reck), new combination

Schizotetranychus ( Eotetranychus ) rubiphilus Reck, 1948, Soobsh. Akad.
Nauk Gruz. S.S.R., 9(6): 374; 9(7): 447. Described from specimens
from Georgia, S.S.R., on Rubus sp.

Subfamily Tetranychinae Herlese

I his species is similar to h. bakuriensis but with a much shorter
aedeagus. The peritreme ends in a simple bulb.

Eotetranychus ulmicola (Reck), new combi not ion

Schizotetrany chus (Eotetranychus) ulmicola Reck, 1048, Soobsh. Akad.
Nauk Gruz. S.S.R., 9(6): 374; 0(7): 449. Described from specimens
Georgia, S.S.R., on L imits spp.

1 he figure of the aedeagus indicates a close relationship with E.
carpini. The peritreme ends in a simple bulb which may be bent weakly
posteriorly.

GENUS NEOTETRANYCHUS TRAGARDH

A eotetranychus lriigardh, 1915, Medd. Centralanst. forsoks. jordbruk.

Ent., 109(20): 23; Tragardh, 1915, Zts. aug. Ent., 2: 163;

McGregor, 1919, Proc. U. S. Natl. Mus., 56(2303): 646; Geijskes,

1039, Meded. Landbouwh. Wageningen, 42(4): 45. Type of genus:

IS eotetranychus rubi Tragardh; monobasic.

Anatetranychus Womersley, 1940, Trans. Roy. Soc. S. Australia, 64(2):

261. Type of genus : Anatetranychus hakea Womersley; monobasic.

New synonymy.

An unusually long extension of the base of the empodium of both
females and males was the basis on which lriigardh differentiated the
genus A eotetranychus from Eotetranychus. McGregor assigned a second
species to A eotetranychus because of a similar development of the
female empodium. However, the male of McGregor’s species departs
even njore from the Eotetranychus pattern in that all empodia are simply
clawlike. I he genus Anatetranychus was based on a species in which
the empodia of the female (male unknown) were described as simply
clawlike.

The species that are here considered under the generic name Aeo-
tetranychus probably do not constitute a phylogenetic unit, the structure
of the empodium representing parallel development. The chaetotaxy
of the legs, the development of the dorsal setae of the body, the form
of the aedeagus and empodium I of the male, and the color of the body
in life all indicate that the species are not closely allied.

216

Spider Mites

Fig. 169. A eotetrany chus rubi: dorsal aspect of female.

217

Subfamily T etrany chinae Berlese

Fig. 170. Seotetranychus rubi : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

218

Spider Mites

Key to the species of Neotetranychus
Females

1. Body with dorsal setae longer than longitudinal intervals between
them and set on tubercles . 2

1. Body with dorsal setae shorter than longitudinal intervals between

them and not set on tubercles ......... 3

2. Tibia II with seven tactile setae (Europe) . . . rubi (p. 218)

2. Tibia II with six tactile setae (southwestern United States)

. siccus (p. 219)

3. Empodium with three pairs of hairs at distal end (eastern United

States) . virginiensis (p. 223)

3. Empodium simply clawlike (Australia) .... hahea (p. 225)

Neotetranychus rubi TragSrdh
(Figures 169, 170, 171, 172)

Neotetranychus rubi Tragardh, 1915, Medd. Central anst. forsoks jordbruk.
Ent., 109(20): 33; McCregor, 1919, Proc. U. S. Natl. Mus.,
56(2303): 647; Geijskes, 1939, Meded. Landbouwh. Uageningen,
42(4): 45. Types : males and females, Stockholm, Sweden, on
Rubus sp.; possibly in the Tragardh collection.

Neotetranychus rubi may be readily
recognized by having long, acutely
tapering setae that are tset on strong
tubercles on the dorsum of the body.
The empodium of the female has a very
long, slender, curved base, and only
the distal end is divided into three
pairs of hairs. The empodia of the male
are similar except that on leg I it
resembles a split claw.

Tibia I of the female bears seven
tactile and one sensory setae, and two
sensory setae are present in the male;
tibia II bears seven tactile setae in
both sexes; and tibia III bears six
tactile setae in both sexes. Tarsus I
bears four tactile setae proximally in
the female, along with two or three
sensory setae in the male.

Fig. 171. Neotetranychus rubi:
empodium of female and terminal
palpal segment of male.

219

Subfamily T etranychinae Rerlese

Ihe aedeagus is sickle-shaped, curved sharply dorsad and tapering
to the tip.

This species is known only from Rubus spp. in Europe. Records are
from Sweden, the type locality, and from Germany. Our material is from
Germany, kindly presented by Ur. F. Zacher.

Neotetranychus siccus Pritchard and Baker, new species
(Figures 173, 174)

Females of Neotetranychus siccus resemble those of A. rubi except
that the body is much smaller and the dorsal setae are narrower and
not borne on as prominent tubercles. The paired hairs at the distal
end of the empodium are quite obvious, and tibia II bears only six
tactile setae. The male is unknown.

220

Spider Mites

Fig. 173. Neotetranychus siccus: dorsal aspect of female.

221

Subfamily Tetrany chinae Berlese

c

Fig. 174. is eo tetrany chus siccus : A.) empodium of female; B.) tibia and
tarsus I of female; C.) tibia and tarsus II of female.

This species is known only from the Arizona desert.

Female. — Palpus with terminal sensillum about three times as long
as broad. Stylophore about twice as long as broad. Peritreme straight
distally, ending in a simple bulb. Tibia I with seven tactile and one
sensory seta; tarsus I with four tactile and one sensory seta proximal
to duplexes; empodium stem slender, slightly longer than the six distal
hairs. Tibia II with six tactile setae. Body with dorsal setae arising
from tubercles, slender, slightly longer than longitudinal intervals
between them. Hysterosomal integumentary striae mostly transverse,
but longitudinal between third dorsocentrals. Length of body 276 p ,
including rostrum 335 g; greatest width of body 193 fi.

Holotype. — Female, Phoenix, Arizona, September 27, 1953 (F. h .
Bibby), on leguminous desert shrub; type no. 2180 in the 1 . S. National
Museum.

Paratypes. — Five females, 3 nymphs, Phoenix, Arizona, September
27, 1953 (F. F. Bibby), on desert shrub (legume).

222

Spider Mites

Fig. 17F>. N eotetranychus virginiensis : dorsal aspect of female,

223

Subfamily T e trany chinae Herlese

Fig. 176. Seotetranychus virginiensis: A.) tibia and tarsus I of female;
B.) tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and
tarsus II of male.

Neotetranychus virginiens is McGregor
(Figures 175, 176, 177, 178)

A eotetranychus virginiensis McGregor, 1950, Amer. Midi. Nat., 44(2):
275. Types : males and females, Arlington Farm, Virginia, on
black locust; in the U. S. National Museum.

224

Spider Mites

Fig. 177. Neotetranychus virginiensis: above, appendages of tarsus I
of male; below, appendages of tarsus II of female.

Adults of Neotetranychus virginiensis
may be recognized by having the dorso-
central hysterosomals shorter than the
longitudinal intervals between them, not
set on tubercles, and the empodium with
a long, slender base. The empodium of
the male forms a simple clawlike append¬
age on all legs, and the aedeagus char¬
acteristically curves slightly ventrad to
form a distal knob having the anterior
and posterior angulations more or less
similarly developed.

Tibia I bears six or seven tactile
setae in the female plus one sensory
seta, and eight tactile setae in the male
plus four sensory setae; tibiae II and III
each bears five tactile setae in both
sexes. Tarsus I bears three (rarely
two or four) tactile setae in both sexes
proximal to the duplexes, plus one sensory seta in the female and
three sensory setae in the male.

This species is known only from black locust in the eastern United
States. Specimens, other than the types, examined are from Beltsville,
Maryland (E. W. Baker), on locust; and Natchitoches, Louisiana (L. D.
Newsom), on black locust.

Fig. 178. Neotetranychus
virginiensis: aedeagus.

225

Subfamily I etrany chinae Berlese

Neotetranychus hakea ( Womersley ), new combination

Anatetranychus hakea Womersley, 1940, lrans. Hoy. Soc. S. Australia,
4(2): 262. T ype: female, Claremont, Western Australia, on llakea
sp.; in the South Australian Museum.

1 he female of hakea differs from other members of the genus A eo-
tetrany chus in that the empodium of this sex is described us being
simply clawlike, and the color of the body in life is reddish. The dorso-
central hysterosomals are slender and shorter than the longitudinal
intervals between them, lhe male is unknown.

1 hi s species is known only from the type female from Australia,
on Eucalyptus.

GENUS SCH1Z0T ETRANY CHUS TRAGARDH

Schizotetranychus Tragardh, 1915, Stockholm Landtbr.-Akad. Handl.,
54: 277; Tragardh, 1915, Medd. Centralanst. forsoks. jordbruck.
Ent. avdeln., 20(109): 20; Tragardh, 1915, Zts. angew. Ent.,
2: 162; McGregor, 1917, Proc. U. S. Natl. Mus., 56(2303): 647;
Geijskes, 1939, Meded. Landbouwh. Wageningen, 42: 28; Garman,
1940, Bui. Conn. Agric. Expt. Sta., 431: 74; McGregor, 1950,
Amer. Midi. Nat., 44: 307. Type of genus: T etrany chus schizopus
Zacher, by original designation.

Stigmaeopsis Banks, 1917, Ent. News., 28: 195. Type of genus: Stigmae-
opsis celarius Banks; monobasic.

Divarinychus McGregor, 1930, Proc. Ent. Soc. Wash., 32: 161. Type of
genus: ( Divarinychus floridensis McGregor) - Schizotetranychus
asparagi (Oudemans); monobasic and by original designation.

P eritetranychus 1 garov and Nikolskii, 1937, Irudy Sredneaz. Stan.
Zasch. Rast., p. 37. Type of genus: P eritetranychus tuberculatus
Ugarov and Nikolskii; by present designation. A etc synonymy.

The genus Schizotetranychus is an offshoot of the Eotetranychus
stem. The ventrolateral pair of empodial hairs is enlarged to form two
clawlike appendages, and this development will serve for generic
recognition. The other two pairs of empodial hairs are extremely thin
in proportional size, usually difficult to see, and sometimes one or
both pairs of hairs are absent.

226

Spider Mites

garmani

asparagi

fluvialis

camur

spireafolia

andropogoni

Fig. 179. S chi zotetrany onus, aedeagi.

227

Subfamily Tetranychinae Berlese

Species of Schizotetranychus are most commonly found on monocoty-
ledonous plants, particularly grasses, but also bamboo, and asparagus.
Other hosts include willow and spirea. 1 he adult females are greenish,
sometimes slightly pinkish, with a number of dark spots of pigment
within the body on each side, lhey spin considerable webbing, and
in the case of S. celarius a dense canopy is spun over each colony
on the under surface of the leaf.

One species, ( Schizotetranychus cercocarpi McGregor) = Eotetrany-
chus deflexus has been erroneously referred to the genus.

Key to North American species of Schizotetranychus
Females

The female of Schizotetranychus camur is unknown.

1. Body with dorsal setae lanceolate, acutely tapering from the
widened proximal portion, nearly nude, and shorter than the
intervals between them; on Spirea . . . spireafolia (p. 248)

1. Body with dorsal setae slender, not obviously widened proximally

. 2

2. (1). Hysterosoma with first pair of dorsocentrals similar in length

to first dorsolaterals . 3

2, (1). Hysterosoma with first pair of dorsocentrals about one-half as

long as first dorsolaterals; on grass. . . eremophilus (p. 251)

3. (2). Hysterosoma with first pair of dorsocentrals similar in length

to second pair of dorsocentrals . 4

3. (2). Hysterosoma with first pair of dorsocentrals about one-half as

long as second pair of dorsocentrals; on bamboo .

. celarius (p. 249)

4. (3). Hysterosoma with dorsal setae much shorter than intervals be¬

tween them . 5

4. (3). Hysterosoma with dorsal setae nearly as long as or longer than

intervals between them .

5. (4). Stylophore very slender, over twice as long as wide; dorsal

setae finely pubescent; on grass . 6

5. (4). Stylophore comparatively broad, only one-third longer than wide;

dorsal setae densely pubescent; on asparagus fern ....
. asparagi (p. 237)

6. (5). Hysterosoma with second and third dorsolaterals similar in length

to second and third dorsocentrals .... fluvialis (p. 254)

228

Spider Mites

6. (5). Hysterosoma with second and third dorsolaterals much longer

than second and third dorso centrals . nugax (p. 264)

7. (4). Empodium with proximolateral chaeta . 8

7. (4). Empodium without proximolateral chaeta . 10

8. (7). Tarsus with ventral tactile setae very strongly pubescent;

hysterosoma with dorsal setae approximately as long or slightly
longer than longitudinal intervals between their bases; on grass
. cynodonis (p. 229)

8. (7). Tarsus with ventral tactile setae minutely pubescent ... 9

9. (8). Hysterosoma with dorsal setae much longer than longitudinal

intervals between them; on grass . . . parasemus (p. 230)

9. (8). Hysterosoma with dorsal setae slightly shorter than longitudinal

intervals between them; on willow . . . schizopus (p. 240)

10. (7). Dorsal hysterosomals far surpassing the longitudinal intervals

between them; on willow . garmani (p. 233)

10.(7). Dorsal hysterosomals slightly longer than longitudinal intervals
between them; on grass . elymus (p. 254)

Males

The males of parasemus and nugax are unknown.

1. Aedeagus flanked by a pair of triangular genital stylets; empodium
with proximolateral chaeta; on grass . . cynodonis (p. 229)

1. Aedeagus not accompanied by genital stylets; empodium without

proximolateral chaeta . 2

2. (1). Aedeagus strongly bent, dorsad or ventrad . 3

2. (1). Aedeagus slender, undulate, caudally directed; on willow .

. garmani (p. 233)

3. (2). Aed eagus bent ventrad, the distal end with an anterior angulation;

on asparagus . asparagi (p. 237)

3.(2). Aedeagus bent dorsad . 4

4.(3). Distal end of aedeagus forming a knob with an acute angulation

anteriorly and a slender angulation posteriorly .

. schizopus (p. 240)

4. (3). Distal end of aedeagus without an anterior angulation . . 5

5. (4). Farsi I and II with some sensory setae fusiform .

. eremophilus (p. 251)

229

Subfamily Tetranychinae Berlese

5. (4). 1 arsi 1 mnl II with sensory setae all slender . 6

6. (5). Aedeagus bent dorsad to form an acute angle; dorsal setae of

body very minutely pubescent, widened proximally and tapering
to a very fine point; on spirea .... spireafolia (p. 248)

6. (5). Aedeagus bent dorsad at not more than a right angle; dorsal

setae of body obviously pubescent and not very acutely tapering
from a widened base; on monocots . 7

7. (6). Aedeagus bent sharply dorsad at nearly a right angle; on grasses

. 8

7. (6). Aedeagus broadly curved dorsad at an obtuse angle; on bamboo .

. celarius (p. 249)

8. (7). Hysterosoma with dorsocentrals less than one-half as long as

longitudinal intervals between them . . . fluvialis (p. 254)

8. (7). Hysterosoma with dorsocentrals nearly as long as longitudinal

intervals between them . 9

9. (8). Bent portion of aedeagus about one-half as long as external

portion of shaft . elymus (p. 254)

9.(8). Bent portion of aedeagus less than one-third as long as external
portion of shaft . camur (p. 260)

Schizotetranychus cynodonis McGregor
(Figures 180, 181, 182)

Schizotetranychus cynodonis McGregor, 1950, Amer. Midi. Nat., 44:
309. Types : 12 males and 18 females, Julian, California, on
Bermuda grass; in the U. S. National Museum.

The male of Schizotetranychus cynodonis is distinctive in that a
pair of triangular plates, the genital stylets, accompany the aedeagus.
These stylets are not known to occur elsewhere in the Tetranychinae.

The female may be recognized by having a pair of proximolateral
chaetae on the empodium, together with having the ventral setae of
the tarsi strongly pubescent.

Schizotetranychus cynodonis has been known only from southern
California, on Bermuda grass and salt grass. New collections are from
San Rafael, California (A. E. Pritchard), on salt grass; Coalinga,
California (A. E. Pritchard), on Agrostis; and Palm Springs, California
(A. E. Pritchard), on Bermuda grass.

230

Spider Mites

Fig. 180. Schizotetranychus cynodonis: dorsal aspect of female.

Schizotetrarrychus parasemus Pritchard and Baker, new species
(Figures 183, 184)

Schizotetranychus parasemus appears to be closely related to S.
cynodonis, and it similarly possesses a pair of proximolateral chaetae
on the empodium. However, the dorsal setae of the body are much
longer in S. parasemus than in S. cynodonis, and the tactile setae of the
tarsi are nearly nude. The male of S. parasemus is unknown.

Female. — Gnathosoma reaching end of femur I, the palpi slightly

231

Subfamily Tetranychinae Berlese

Fig. 181. Schi zotetranychus cynodonis: A.) tibia and tarsus I of female;
B.) tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and
tarsus II of male.

longer than the rostrum. Palpus with terminal sensillum on fifth segment
slender, about four times as long as wide, the mediodorsal sensilla
somewhat long, and the proximal, fusiform sensillum also slender
and somewhat longer. Peritreme straight distilly, ending in a bulb.
Tibia I with seven tactile setae and one sensory seta; tarsus 1 slender

232

Spider Mites

Fig. 182. Schi zotetranychus cynodonis: A.) terminal segment of palpus
of male; B.) terminal segment of palpus of female; C.) aedeagus.

with three tactile setae and a sensory seta as proximal end; and all
tactile setae minutely pubescent. Tibia II with six tactile setae; tibia
III with five tactile setae. Empodium with each of the clawlike divisions
bearing a pair of fine dorsal hairs, and with an obvious pair of proxi-
molateral chaetae. Body with dorsal setae very long, reaching nearly
to base of second seta caudad, tapering and densely pubescent. Length
of body including rostrum 346 p; greatest width of body, 193 p.

Holotype. — Female, Nortonville, 10 miles east of Clayton, Contra
Costa County, California, October 15, 1952 (Vi. C. Bentinck), on
Distiehlis spicata; type no. 2128 in the U. S. National Museum.
P aratypes. — Female, Nortonville, California, October 15, 1952

(W. C. Bentinch), on Distiehlis spicata; 3 females, 1 nymph, Clayton,
California, October 8, 1952 (J. W. MacSwain), on salt grass; 5 females,
Sage, California, August 23, 1935 (E. A. McGregor), on Cynodon sp.

Schi zotetranychus oudemansi Reck

Schizotetranychus schizopus, Oudemans, 1931, Ent. Ber. 8(179): 260,
261; Geijskes, 1939, Meded. Landbouwh. Rageningen, 42(4): 28,
29. On Vaccinium uliginosum, Winterswijk, Holland. Misidentifi-
cation.

Schizotetranychus oudemansi Reck, 1948, Soobsh. Akad. Nauk Gruz.
S.S.R., 9(6): 374, 375.

Until Oudemans’ material can be studied the exact status of this
species will remain in doubt. It is probably closely related to S. cynodonis
and S. paras emus , with all dorsal setae of equal length but longer than
the longitudinal intervals between them.

233

Subfamily 7 etranychinae H erlese

Fig. 183. Schi zotetranychus parasemus : dorsal aspect of female.

Schi zotetranychus garmani Pritchard and Baker, new species
(Figures 185, 186, 187, 188)

Schi zotetranychus schizopus, Carman, 1940, Bui. Conn. Agric. Exp.
Sta., 431: 74. Misidentification.

Carman’s identification of Schizotetranvchus schizopus Zacher,
from Connecticut, is not accepted because the aedeagus of the New
England species differs markedly from that of S. schizopus as figured
by Hirst (1920) and McGregor (1950).

234

Spider Mites

Fig. 184. Schizotetranychus parasemus : A.) tibia and tarsus I of female;
B.) tibia and tarsus II of female; C.) terminal segment of palpus of female;
D.) empodium I of female; E.) lateral view of female empodium.

The aedeagus of S. garmani is distinctive in that it forms a slender,
undulating rod as in Eotetrany chus carpini and related species. The
female does not possess a pair of proximolateral chaetae on the em¬
podium, and the dorsal setae of the body are all long and slender,
much longer than the longitudinal intervals between them.

This species is known only from Connecticut, on willow.

Male. — Fifth segment of palpus with terminal sensillum moderately
slender, about four times as long as wide at base; mediodorsal sen¬
sillum about as long as terminal sensillum; the proximal, fusiform
sensillum shorter. Peritreme straight distally, ending in a simple
chamber. Tibia I with eight tactile and four sensory setae; tarsus I short
with duplex setae just beyond middle of segment, with four tactile
and three sensory setae proximal to the duplexes; empodial claws I each
with three slender teeth of which the inner, ventral tooth is fine. Tibia
II with eight tactile setae; tibia III with six tactile setae; empodia

235

Subfamily I etrany chinae Berlese

Fig. 185. Schizotetrunychus garmani : A.) tibia and tarsus I of female; R.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of male.

236

Spider Mites

Fig. 186. Schizotetranychus gar-
mani : A.) terminal segment of palpus
of female; B.) terminal segment
of palpus of male.

II-IV with two pairs of very fine
hairs dorsally on each clawlike
division; proximolateral chaeta
minute. Dorsum of body with very
long setae, much longer than inter¬
vals between them. Aedeagus very
long and slender, tapering, caudally
directed but with distinct wave near
the middle. Length of body, 213 p’,
including rostrum, 272 p.

Fig. 187. Schizotetranychus garmani: A.) appendages of tarsus I of male;
B.) appendages of tarsus IV of male; C.) appendages of tarsus I of female.

Female. — Similar to male except tibia I with two or three sensory
setae and tarsus I with a single sensory seta proximally; empodial
claws with dorsal hairs less evident and proximolateral denticulation
more evident; and dorsal setae of body only about as long as longitu¬
dinal intervals between them. Length of body, 316 p, including rostrum,
383 p; greatest width of body, 210 p.

Uolotype. — Male, Hamden, Connecticut, September 24, 1922, on
willow leaves; type no. 2127 in the U. S. National Museum. Paratypes. —
Eight females, Hamden, Connecticut, September 24, 1922, on willow;
13 females, Amherst, Massachusetts, July 17, 1950 (W. B. Becker),
on willow.

This species is named in honor of Philip Garman, a pioneer in the
study of spider mites in North America.

237

Subfamily T etrariy chinae Herlese

Fig. 188. Schi zotetranychus garmani: aedeagus.

Schizotetranychus asparagi ( Oudemans )

(Figures 189, 190, 191)

Epitetranychus asparagi Oudemans, 1928, Ent. Ber., 7 : 288. Types :

males and females, Amsterdam, Holland, on Asparagus springeri.
Schizotetranychus asparagi, Oudemans, 1931, Ent. Ber., 8: 292;

Geijskes, 1939, \leded. Landbouwh. Wageningen, 42: 29;

Pritchard, 1949, Bui. California Exp. Sta., 713: 7.

Divarinychus floridensis McGregor, 1930, Proc. Ent. Soc. Wash., 32:
161. Types: males and females, Longvvood, Florida, on Asparagus
plumosus; in the U. S. National Museum. New synonymy.
Schizotetranychus floridensis, McGregor, 1950, Amer. Midi. Nat., 44:
312. "

Females of Schizotetranychus asparagi may be readily recognized
by having the dorsal setae of the body all similar in length, slender,
densely pubescent, and much shorter than the intervals between them.
The stylophore is comparatively broad, little longer than wide.

The male of Schizotetranychus asparagi is distinctive in that the
aedeagus turns rather abruptly ventrad, and the distal end is nearly
sigmoid with an anterior angulation on the barb.

This species is found only on Asparagus ferns, which are usually
grown under greenhouse or lath-house conditions in the United States.
Asparagus springeri and A. plumosus are the only recorded hosts.
Holland, Florida, and California are the only localities from which
the mite has been recorded.

238

Spider Mites

Fig. 189. Schizotetranychus asparagi: dorsal aspect of female.

Collections studied by us, in addition to the types of floridensis,
are from Oakland and Colma, California (A. E. Pritchard), on Asparagus
plumosus; Rio Piedras, Puerto Rico (F. Sein), on /Lsparagus plumosus;
Waipahu, Hawaii (C. Schmidt), on Asparagus sp.; Washington, D. C.
(Smith and Lung), on Asparagus plumosus; and Deland, Florida
(M. L. Wright), on Asparagus plumosus.

239

Subfamily 1 etrany chinae Herlese

Fig. 190. Schizotetranycnus asparagi : A.) tibia and tarsus 1 of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; C.) tibia and tarsus
II of male.

240

Spider Mites

Fig. 191. Schi zotetranychus asparagi : A.) aedeagus; B.) empodium III of
female; C.) empodium I of male; D.) palpus of male; E.) palpus of female.

Schi zotetranychus schizopus ( Zacher )

(Figures 192, 193)

Tetranychus schizopus Zacher, 1913, Mitt. kais. biol. Anst. Land
Forst., 9: 40; Hirst, 1920, Proc. Zool. Soc. Lond. 1920 : 50.
Types: from Dahlem, Germany, on willow; possibly in the
Zacher collection.

Schizotetranychus schizopus , Tragardh, 1915, Stockholm Landtbr.-
Akad. Handl., 44: 277; Tragardh, 1915, Medd. Centralanst.
fdrsoks. jordbrucks. Ent. avdeln., 20(109): 20; Tragardh, 1915,
Zts. angew. Ent., 2: 162; Zacher, 1921, Zts. angew. Ent., 7:
184; McGregor, 1917, Proc. U. S. Natl. Mus., 56(2303): 648;
Oudemans, 1931, Ent. Ber., 8(179): 260; Geijskes, 1939, Meded.
Landbouwh. Wageningen, 42 : 28; Reck, 1948, Soobsh. Akad.
Nauk Gruz. S.S.R., 9(7): 450; McGregor, 150, Amer. Midi. Nat.,
44: 313.

1 he male of Schizotetranychus schizopus may be readily recognized
by having an anterior angulation on the distodorsad curvature.

1 he female may be recognized by having a pair of obvious proximo-
lateral chaetae on the empodium and the empodial “claws”'each with a
single dorsal hair. The dorsal hysterosomals are slightly shorter than
the longitudinal intervals between them.

Subfamily / etrunychinae Herlese

Fig, 192, 5 chi zo tetrany chus s cm zopusi A .) tibia and tarsus 1 o
B.) tibia and tarsus II of female; C.) tibia and tarsus I cf male; D.)
tarsus II of male.

f female;
tibia and

242

Spider Mites

Fig. 193. Schizotetranychus sctiizopus: A.) empodium I of male; P.)
empodium II of male; C.) empodium I of female; D.) terminal segment of palpus
of male; E.) terminal sensillum of palpus of female; F.) aedeagus.

This species is known from Europe and Georgia, S.S.R., on willow.
Material examined by us is from Ithaca, New York (J. G. Matthysse), on
willow. The species recognized by Garman (1940) under this name is
described as Schizotetranychus garmani in this publication.

Schizotetranychus cornus Pritchard and Baker, new species
(Figures 194, 195, 196, 197)

The male of cornus differs from all other members of the genus
Schizotetranychus in that the aedeagus is caudally directed and simple
except for a small, terminal enlargement (much as in Eotetranychus
perplexus). The adult female may be recognized by having all the
hysterosomals similar in length and less than one-half as long as the
intervals between them.

I his species is known only from New Zealand, on Elaeocarpus.

Male. — Palpus with terminal sensillum of fifth segment nearly twice
as long as broad at base and triangular; mediodorsal sensilla slender

243

Subfamily 1 etruny chiriae Herlrse

Fig. 194. Sctiizotetranychus cornus: dorsal aspect of female.

244

Spider Mites

Fig. 195. Schizotetranychus cornus : A.) tibia and tarsus I of female; B.)
tibia and tarsus 11 of female; C.) tibia and tarsus 1 of male; D.) tibia and tarsus
II of male.

Subfamily I etranychinae Herlese

Fig. 196. Schi zotetranychus cornus: A.) appendages of tarsus I of female;
B.) appendages of tarsus I of male; C.) terminal segment of aplpus of male;
D.) terminal segment of palpus of female.

with one twice as long as the other;
proximal, fusiform sensillum similar to
shorter mediodorsal sensillum. Peritreme
with distal end hooked. Tibia I with six
tactile and one sensory seta; tarsus I
very short, with one tactile and one
sensillum at proximal end of segument.
Tibia II and III with five tactile setae.
Empodia I and II with three very strong
cusps on each digit; empodia III and IV
with a pair of dorsal hairs on each of the
clawlike parts. Body with dorsal setae
slender and pubescent, somewhat less
than one-half as long as longitudinal
intervals between them. Aedeagus
straight, several times longer than wide
at base, gradually narrowing, and with
the distal end slightly widened, especially
caudoventrally. Length of body, 293 p;
greatest width of body, 170 p.

Female. — Similar to male, the terminal sensillum of the palpus
larger, not over twice as wide as long; dorsal setae of body even shorter
than in the male; and all empodial claws with a pair of dorsal setae
and a pair of obvious proximolateral chaetae. Length of body, 345 P ,
including gnathosoma 450 p; greatest width of body 200 p.

Fig. 197. Schi zotetranychus
cornus : aedeagus.

246

Spicier Mites

Holotype. — Male, Levin, New Zealand, December, 1949 (A. Lush),
on Elaeocarpus dentatus; type no. 2138 in the U. S. National Museum.
Paratypes. — Five males, 12 females, Levin, New Zealand, December
1949 (A. Lush), on Elaeocarpus dentatus.

247

Subfamily I etrariychinue Herlese

Fig. 199. Schi zotetrimychus spireafolia: A.) tibia and tarsus I of female;
R.) tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and
tarsus II of male.

248

Spider Mites

Fig. 200. Schizotetrany chus spireafolia : A.) appendages of tarsus III of
female; B.) distal segment of palpus of female; C.) appendages of tarsus I of
male; D.) distal segment of palpus of male.

Schizotetranychus spireafol ia Garman
(Figures 198, 199, 200, 201)

Schizotetrany chus spireafolia Garman, 1940, Bui. Conn. Agr. Exp.
Sta., 431: 74; McGregor, 1950, Amer. Midi. Nat., 44: 315. Types :
all stages, Connecticut, on Spirea lati(olia\ in the collection
of the Connecticut Agricultural Experiment Station.

Specimens of Schizotetrany chus spireafolia may be readily recog¬
nized by the shape of the dorsal setae on the body. These setae are
very minutely pubescent, widened near each base, tapering to a slender,
acute tip, and they are somewhat shorter than the longitudinal intervals
between them. The aedeagus bends upward at less than a right angle
to form a slender, sigmoid, acuminate tip.

Schizotetranychus spireafolia, previously known only 'from Spirea
latifolia in Connecticut, has been collected on a similar host in Phila¬
delphia, Pennsylvania (T. Parr).

Schizotetranychus andropogoni (Hirst), new combination
(Figures 202, 203, 204)

Tetranychus ( Schizotetranychus ) andropogoni Hirst, 1926, Proc. Zool.
Soc. Eond., 1926: 829. Types: male and female, Coimbatore,
India, on Andropogon annulatus; in the British Museum (Natural
History).

249

Subfamily 7 etrany chinae Herlese

Fig. 201. Schizotetranychus
spireafolia: aedeagus.

Adults of Schizotetranychus
andropogoni resemble those of 5.
spireafolia in that the dorsal setae
setae of the body are very minutely
pubescent and lanceolate, being
broadened proximally and finely
tapering distally. In the female,
however, the dorsal setae are about
as long as the longitudinal inter¬
vals between them. In the male,
the aedeagus distally forms a dor-
sally directed sigmoid curve, but
it is less acutely turned than in
spireafolia.

Specimens studied by us are
from Coimbatore, India, August 12,
1950 (G. H. Rao), on Saccharum
spontanum.

Schi zotetranychus ce/arius (Banks)

(Figures 205, 206, 207)

Stigmaeopsis celarius Banks, 1917, Ent. News, 28: 196; Essig, 1926,
Insects West. N. Amer., p. 32. Types : females, Oneco, Florida,
on bamboo; in the U. S. National Museum.

Schizotetranychus celarius, McGregor, 1950, Amer. Midi. Nat., 44 : 308.
Schizotetranychus latitarsus Ewing, 1917, Jour. Econ. Ent., 10: 498.
Types: females, Pasadena, California, on bamboo.

Females of Schizotetranychus celarius may be readily recognized
by having the first pair of dorsocentral hysterosomals about one-half
as long as the second pair of dorsocentrals and similar in length to
the first pair of dorsolateral hysterosomals. The aedeagus is distinctive
in being broadly curved dorsad.

This species is found only on bamboo. It forms restricted colonies
on the undersides of the leaves and lives underneath a dense cover
of webbing.

Schizotetranychus celarius is known only from Florida, Georgia,
and California.

250

Spider Mites

Fig. 202. Schizotetranychus andropogoni: A.) tibia and tarsus I of female;
B.) tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and
tarsus II of male.

251

Subfamily l e trany chinae Herlese

Sch izotetranychus bambusae Reck

Schizotetranychus bambusae Heck, 1941, Soobsh. Akad. Nauk. Gruz.
S.S.R., 2(5); Heck 1948, Soobsh. Akad. Nauk. Gruz. S.S.H.,
9(5): 375; 9(7): 451. Described from specimens from Georgia,
S.S.R., on Phyllostachys spp.

Fig. 203. Schizotetranychus andro-
pogoni: A.) terminal segment of pal¬

pus of female; B.) terminal segment
of palpus of male; C.) tarsal append¬
ages of female.

The description of the aedeagus
states that it is short and with
a hook. S. celarius , also from bam¬
boo, has the aedeagus broadly
curved dorsad.

Fig. 204. Schizotetranychus
andropo goni : aedeagus.

Schizotetranychus eremophi lus McGregor
(Figures 208, 209, 210, 211)

Schizotetranychus eremophilus McGregor, 1950, Amer. Midi. Nat.,
44: 311. Types: males and females, Plaster City, California,
on Bermuda grass; in the U. S. National Museum.

Adults of Schizotetranychus eremophilus may be readily recognized
by having the first pair of dorsocentral hysterosomals much shorter
than both the second pair of dorsocentral hysterosomals and the first
pair of dorsolateral hysterosomals.

252

Spider Mites

Fig. 205. Schizotetranychus celarius : dorsal aspect of female.

253

Subfamily 1 etrany chinae Series?

Fig. 206. Schizotetranyckus celarius : A.) tibia and tarsus I of female;
B.) tibia and tarsus I of male; C.) tarsus II of female; D.) tarsal appendages
of female; E.) tibia and tarsus II of female; F.) tibia and tarsus II of male.

Two sensory setae on tibia I and the three proximal sensory setae
on tarsus I of the male are fusiform, and this is distinctive of the sex.
The aedeagus bends upward to form a sigmoid distal end as in Schizo-
tetranychus elymus, S. fluvialis, and S. camur.

This species is known only from southern California, on Bermuda
grass. New collections are from the Coachella Valley, California (R. h.
Smith), on Bermuda grass; Bond’s Corner, 15 miles east of Calexico,
California (F. M. Summers), on Bermuda grass; and Riverside, California
(Jack Hall), on Bermuda grass.

254

Spider Mites

Fig. 207. Schizotetranychus celarius : A.) distal segment of palpus of female;
B.) distal segment of palpus of male; C.) aedeagus.

Schizotetranychus fluvial is McGregor
(Figures 212, 213, 214, 215)

Schizotetranychus fluvialis McGregor, 1928, Proc. Ent. Soc. \lash.,
30; 13; McGregor, 1950, Anier. Midi. Nat., 44: 313. Types: males
and females, Lemon Cove, California, on Epicampes rigens; in
the U. S. National Museum.

The female of Schizotetranychus fluvialis may be recognized by
having the dorsal setae of the body slender, much shorter than the
longitudinal intervals between them, and rather finely pubescent.

The aedeagus resembles that of Schizotetranychus eremophilus,
S. elymus, and S. camur in that the distal end forms a dorsally directed
sigmoid curve. However, the short dorsal setae of the body will serve
for differentiation. This species is known only from the type series
from central California, on grass.

Schizotetranychus elymus McGregor
(Figures 216, 217, 218, 219)

Schizotetranychus elymus McGregor, 1950, Amer. Midi. Nat., 44(2): 310.
Types: males and females, Pine Valley, San Diego County,
California, on Elymus sp.; in the U. S. National Museum.

The male of Schizotetranychus elymus may be recognized by having
the aedeagus with a dorsally directed sigmoid portion that is about

255

Subfamily Tetranychinae H erlese

Fig. 208. Schizotetranychus eremophilus: dorsal aspect of female,

256

Spider Mites

l'ig. 209. Schizotetranychus eremophilus: A.) tibia and tarsus I of female;
H.) tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and
tarsus II of male.

257

Subfamily i etrany ckinae Kerlese

Fig. 210. Schi zotetranychus eremophilus: A.) appendages of tarsus 1 of
female; R.) appendages of tarsus 1 of male; C.) distal segment of palpus of
female; D.) distal segment of palpus of male.

one-half a9 long as the shaft, to¬
gether with having the dorsal setae
of the body similar in length,
slender, and slightly longer than
the longitudinal intervals between
them.

The female may be recognized by
having similar dorsal setae on the
hysterosoma; and no proximolateral
chaeta is evident on the empodium.

This species is known only from
the western United States. Collec¬
tions studied, other than the types,
are from Coalinga, California (A. E.
Pritchard), on Agrostis sp.; Niles,
California (A. E. Pritchard), on
Bermuda grass; Tesla, California
(J. E. Gillaspy and A. E. Pritchard),
on grass; Modesto, California (R.
E. Beer), on grass; Antioch, Cali¬
fornia (ft. C. Bentinck), on grass;
and Logan, Utah (G. F. Knowlton).

Fig. 211. Schi zotetranychus
eremophilus: aedeagus.

258

Spider Mites

Fig. 212. Schi zotetranychus fluvialis: dorsal aspect of female.

259

Subfamily / e trany chinae Herlese

Fig. 213. Schi zotetranychus fluvialis: A.) tibia and tarsus I of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of male.

260

Spider Mites

Fig. 214. Schizotetranychus fluvialis:

A. ) distal segment of palpus of female;

B. ) distal segment of palpus of male;

C. ) appendages of tarsus I of female.

Fig; 215. Sent zotetranychus
fluvialis : aedeagus.

Schizotetranychus camur Pritchard and Baker, new species

(Figure 220)

The male of Schizotetranychus camur may be recognized by having
the aedeagus with the distal one-third dorsally directed and sigmoid,
together with having the dorsal setae of the hysterosoma similar and
slender, nearly as long as the longitudinal intervals between them.
No proximolateral chaeta is evident on the empodium. The female is
unknown.

This species is known only from Florida, on grass.

Male. — Palpus with terminal sensillum absent. Stylophore slender,
rounded anteriorly; peritreme hooked distally. Tibia I with seven tactile
and two sensory setae; tarsus I short and abruptly declivate distally,
with one tactile and three sensory setae proximal to duplexes; empodium
composed of two simple claws, without dorsal setae or proximolateral
chaetae. Tibia II with five tactile setae. Hysterosoma with dorsal
setae slender, tapering, nearly as long as longitudinal intervals between
them, but with longer humerals. Aedeagus with distal one-third bent
dorsad at a right angle, the distal end curved caudad. Length of body
320 p, including rostrum 400/x; greatest width of body 200 p.

Ilolotype. — Male, Fast Palatka, Florida, February 27, 1950 (0. D.
Link), on reed grass; type no. 2188 in the F. S. National Museum.
Paratypes. — I wo males, 1 larva, 1 nymph, East Palatka, Florida,
February 27, 1950 (0. I). Link), on reed grass.

261

Subfamily 1 etrany chinae Herlese

Fig. 216. Schizotetranychus elymus: dorsal aspect of female,

262

Spider Mites

Fig. 217. Schizotetranychus elymus: A.) tibia and tarsus I of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of male.

263

Subfamily l etrany chinae Herlesr

Fig. 218. Scni zotetranychus elymus: A.) distal segment of palpus of male;
FI.) distal segment of palpus of female; C.) appendages of tarsus of female.

Fig. 219. S chi zotetranychus elymus : aedeagus.

264

Spider Mites

F

Fig. 220. Schizotetranychus camur : A.) lateral view of aedeagus; H.) dorsal
aspect of aedeagus; C.) tibia and tarsus II of male: D.) appendages of tarsus I
of male; E.) tibia and tarsus I of male; F.) distal segment of palpus of male.

Schizotetranychus nugax Pritchard and Baker, new species
(Figures 221, 222)

The female of Schizotetranychus nugax may be recognized by having
the dorsocentral hysterosomals shorter than the intervals between them,
the second and third dorsolaterals being much longer. The male is
unknown.

Female. — Stylophore slender, nearly acuminate anteromedially.
Tibia 1 with seven tactile and one sensory setae; tarsus I short and
abruptly declivate distally, with two tactile and one sensory setae
setae proximal to the duplexes; empodium consisting of two simple

Subfamily Tetranychinae Herlese

Fiu. 221. Scnizotetranychus nugax'. dorsal aspect of female.

claws, without dorsal setae or proximolateral chafetae. Propodosonia
with dorsal setae somewhat shorter than intervals between them, slender,
tapering, and finely pubescent: hysterosoma with dorsocentrals and

266

Spider Mites

Fig. 222. Schizotetranychus nugax: A.) tibia and tarsus I of female; B.)
tibia and tarsus II of female; C.) appendages of the female tarsus.

first dorsolaterals similar in length, shorter than the longitudinal inter¬
vals between them; other dorsal hysterosomals considerably longer.
Length of body 283 fi, including rostrum 333 p ; greatest width of body
133 p.

Holotype. — Female, Portales, New Mexico, August, 1953, (T. L.
Harvey), on native grasses; type no. 2189 in the U. S. National Museum.
Paratypes. — Twenty-eight females, Portales, New Mexico, August,
1953, (T. L. Harvey), on native grasses.

Schizotetranychus hindustanicus {Hirst), new combination

Tetranychus ( Schizotetranychus ) hindustanicus Hirst, 1924, Ann. Mag.
Nat. Hist. (ser. 14), 9: 525. lypes: males and females, Coimba¬
tore, South India, on citrus; probably in the British Museum
(Natural History).

267

Subfamily T etranychinae Herlese

Fig. 223. Oligonychus, aedeagi of species on conifers.

This species is known only from the type series from South India,
on citrus. The description and figures of the aedeagus indicates that
Schizotetranychus hindustanicus is closely allied to those species
in which the distal portion turns dorsad to form a sigmoid distal end.
However, the dorsal aspect of the distal curvature of the aedeagus is
distinctively truncate.

Schizotetranychus graminicola Goux

Schizotetranychus graminicola Goux, 1949, Bui. Soc. Linn. Lyon, 18(6):
100. Types', males, females, and immature stages, Bessenay
(Rhone), France, on grass.

268

Spider Mites

Fig. 224. Oligonychus, aedeagi.

1 he illustration of the adults of Schizotetranychus graminicola
that was presented by Goux indicates that this species may be readily
recognized by having the second pair of dorsocentral hysterosomals
greatly longer than the other dorsocentral and dorsolateral hystero-
somals. The figure of the aedeagus indicates that this species is
closely allied to Schizotetranychus eremophilus, S. elymus, S. fluvialis,
and S. camur. This species is known only from the type series.

269

Subfamily i etrany chinae Herlese

Schizotetranychus tuberculatus (Ugarov and Nikolskii), new
combi nation

P eritetranychus tuberculatus Ugarov and Nikolskii, 1937, Trudy
Sreadneaz. Stan. Zasch. Hast., p. 37. Described from females,
lashkent, Russia, on mulberry.

1 wo species of Schizotetranychus that are known from Russia are
distinctive in that the dorsal setae of the body are borne on tuber¬
cles. In S. tuberculatus the dorsal setae are strongly pubescent. This
species is known only from the types.

Schizotetranychus glabri setus ( Ugarov and Nikolskii), new
combination

P eritetranychus glabrisetus Ugarov and Nikolskii, 1937, Trudy Sread¬
neaz. Stan. Zasch. Rast., p. 39. Described from a single female,
Tashkent, Russia, on grass.

Schizotetranychus glabrisetus was described on the basis of a single
female that differs from S. tuberculatus in that the dorsal setae of the
body are nearly nude.

Sch i zotetranychus guatemalae-novae {Stoll), new combination

Tetranychus guatemalae-novae Stoll, 1886, Biol. Cent.-Amer., Zool.,
Arach., Acar., p. 8. Described from Guatemala City, on Cassia
nic titans.

This species was recorded as webbing the undersides of the leaves
of wild sensitive plant near Guatemala City. The description allows
reference of the species to the genus Schizotetranychus , but no further
diagnosis is possible.

Schizotetranychus ibericus Reck

Schizotetranychus ibericus Reck, 1947, Soobsh. Akad. Nauk Gruz.
S.S.R., 8(7); Reck, 1948, Soobsh. Akad. Nauk Gruz. S.S.R.
9(6): 375; 9(7): 451. Described from specimens from Georgia,
S.S.R. , on Quercus spp.

270

Spider Mites

modestus

Fig. 225. Oligonychus, aedeagi.

The bent portion of the aedeagus is at right angles to the shaft, and
the tip is curved slightly candad somewhat similar to that of elymus.
The body setae are long, reaching to the bases of the setae of the next
row.

GENUS OLIGONYCHUS BERLESE

Oligonychus Berlese, 1886, Acari Dann. Piante Coltiv., p. 24;
Canestrini, 1889, A tti lleale 1st. Veneto Sci. Let. Arti (ser. 6),
7: 532, 534; Banks, 1917, Lnt. News, 28: 197; Hirst, 1920, Proc.
Zool. Soc. Lond., 1920: 58; Kwing, 1921, Proc. U. S. Natl. Mus.,

271

Subfamily T etrany chinae llerlese

59(2394): 659. I ype of genus: ileteronychus brevipodus Targioni
1 ozzetti; monobasic.

Paratetranychus Zacher, 1913, Mitt. Kais. biol. Anst. Land-. Forst.,
14: 39; lriigardh, 1915, Zts. angew. Ent., 2: 162; McGregor,
1919, Proc. U. S. Natl. Mus., 56(2303): 665; Geijskes, 1939,
Meded. I .andbouwh. Wageningen, 42(4): 33; Carman, 1940, Bui.
Conn. Agr. Exp. Sta., 43: 75; McGregor, 1950, Amer. Midi. Nat.,
44: 329; Baker and Pritchard, 1953, Hilgardia, 22(7): 209, Type
of genus: Tetranychus ununguis Jacobi; by present designation.
Panonychus Yokoyama, 1929, Nippon Sangyo Gaichu Zensho (Tokyo),
p. 531. lype of genus : P anonychus mori Yokoyama; monobasic.
N eiv synonymy.

Tacebia Yokoyama, 1929, Nippon Sangyo Gaichu Zensho (Tokyo), p.
536. Type of genus: Tacebia parva Yokoyama; monobasic. A'eu;
synonymy.

Berl ese’s description of the genus Oligonychus was based on his
identification of brevipodus Targioni Tozzetti, from holly oak in Italy.
Both authors emphasize that the empodium is clawlike, and Berlese
further noted, although inaccurately, that proximoventral hairs are
present. Several acarologists have considered Oligonychus to have
priority over Paratetranychus, and we have no reason not to accept
this synonymy.

The genus Rhodaxes Kirchner, 1863, has been regarded by some
workers as possibly being synonymous with Oligonychus. ^e regard
Rhodaxes as belonging to the Eriophyidae.

Mites belonging to the genus Oligonychus may be recognized by
having the empodial claw well developed, with six to twelve hairs
proximoventrally, and the caudal pair of para-anal setae absent.

These mites are usually found on trees, shrubs, or perennial grasses,
where they overwinter in the temperate zone as eggs. The egg bears
a dorsal stipe and is more or less radially striated dorsally; and it is
reddish or amber when laid by reddish females or pearly when laid by
greenish females. The mites usually feed on the dorsal surface of
broad leaves ( Oligonychus aceris is an exception), and leave the entire
upper surface speckled.

The number of tactile setae on tibia I and tarsus I are here employed
for segregation of species groups or subgroups. The number of sensory
setae on these segments is often constant, as in other genera, but
sometimes subject to considerable variation. Moreover, the proximal
tactile setae on tarsus I of the female may be of a distinctive number
when males all exhibit similar numbers of tactile setae. Exceptions,

272

Spider Mites

of course, are sometimes encountered,
but the present breakdown on this
basis has proved to be very useful for
identification. Males have more sensory
setae than the females, as a rule.

We recognize five major species
groups of the genus Oligonychus and
each is probably worthy of subgeneric
rank.

The first group consist of Oligonychus
ununguis and related species in which
the aedeagus bends down. The fore tibia
bears only five, six, or seven tactile
setae, and the fore tarsus bears from
none to four tactile setae proximal of
the duplex setae and one ventral, tactile
seta (with one exception) just distal
to the duplex setae (on the portion
with longitudinal striae). The empodium bears four to six pairs (appar¬
ently only three pairs in 0. cunliffei and the fore tarsus of males of
some species) of ventral hairs proximoventral to the empodial claw.

The second group consists of Oligonychus peruvianus alone. The
configuration of the dorsal striae of the idiosoma is distinctive. The
fore tarsus agrees with the Ununguis Group in that there is a single
tactile seta ventrodistad of the duplex setae. The aedeagus bends
ventrad also as in 0. ununguis. However, tibia I bears nine tactile
setae, and the empodium consists of only three pairs of proximoventral
hairs, both characters being as in the following groups.

The remainder of the genus Oligonychus consists of those species
in which the aedeagus bends dorsad, and tibia I bears eight or usually,
nine tactile setae. There are two tactile setae ventral ly at or just
beyond the duplex setae of tarsus I (on the portion with longitudinal
striae); and there are only three pairs of proximoventral hairs on the
empodium. The dorsal striae of the body of the female as well as the
structure of the aedeagus will separate the Pritchardi, Pratensis, and
McGregori Groups.

It is emphasized that the following key is not infallible. Occasionally
a specimen is encountered in which a tactile seta of the leg is lacking
or else an additional seta is present. However, the tactile setae of
the tibia and tarsi have proved to be much more constant than the
sensory setae on these segments, and their numbers are valuable,
at least with consideration to populations, for purposes of identification.

biharensi s

Fig. 226. Oligonychus, aedeagi.

273

Subfamily Tetranychinae fieri ese

l.

1.

2.(1).

2.(1).

3,(2).

3. (2).

4. (3).

4.(3).

5.(4).

5. (4).

6. (5).

6. (5).

7. (2).

7. (2).

8. (7).

8.(7).

Key to American and Hawaiian species of OLIGONYCHUS
Females

libia I with five, six, or seven tactile setae; tarsus I with a
single tactile seta on venter beyond first duplex; empodium
usually with four to six pairs of proximoventral hairs (Ununguis

Group) . 2

libia I with eight or nine tactile setae; tarsus 1 usually with
two tactile setae on venter beyond first duplex; empodium
with only three pairs of proximoventral hairs . 13

Hysterosoma with first pair of dorsocentrals not reaching

bases of second pair . 3

Hysterosoma with first pair of dorsocentrals reaching well
beyond bases of second pair . 7

Tibia I with seven tactile (and one sensory) setae; tarsus 1
with three tactile (and one sensory) setae proximal to duplex
setae; on cypress (Boudreauxi Subgroup) . boudreauxi (p. 291)
libia I with five or six tactile (and one sensory) setae; tarsus
I with one or no tactile (and one sensory) setae proximal to
duplex setae; on pine (Subnudus Subgroup) . 4

Hysterosoma with first pair of dorsocentrals over one-half as
long as interval to second pair; dorsal setae and para-anals

nearly nude . pityinus (p. 290)

Hysterosoma with first pair of dorsocentrals less than one-half
as long as interval to second pair; dorsal setae and para-anals
obviously pubescent . 5

Dorsocentral hysterosomals with anterior pair much shorter

than posterior pair . milleri (p. 280)

Dorsocentral hysterosomals all similar in length .... 6

Tarsi III and IV much longer than tibiae III and IV, and grad¬
ually narrowing distally . subnudus (p. 281)

Tarsi III and I\ subequal in length to tibiae III and I\ and
abruptly declivate at tip . cunliffei (p. 284)

Tibia I with six tactile (and one sensory) setae (Aceris Subgroup) 8
Tibia I with seven tactile setae (and one or more sensory)
setae . 9

Idiosoma with dorsal setae not conspicuously heavy; sensory
seta on tibia I more than one half as long as dorsal tactile seta;

on maple . aceris (p. 297)

Idiosoma with dorsal setae large; sensory seta on tibia I about

274

Spider Mites

9.(7).

9. (7).

10. (9).

10. (9).

11. (10).
11.(10).

12.(9).

12. (9).

13. (1).

13. (1).

14. (13).

14. (13).

15. (14).

15. (14).

16. (14).
16.(14).

one fourth as long as dorsal tactile setae; on oak and chest¬
nut . endytus (p. 301)

Tarsus I with three tactile setae proximal to duplex setae ( Hi-
color Subgroup) .

Tarsus I with four tactile setae proximal to duplex se*.

guis Subgroup) .

Duplex setae with proximal member nearly as long as distal

seta . platani (p. 304)

Duplex setae with proximal member very short in comparison
with distal setae . 11

Outer sacrals much shorter than inner sacrals. .ilicis (p. 305)
Outer sacrals similar in length to inner sacrals ....

• bicolor, viridis, neiccomeri, coffeae (pp. 308, 311, 312, 315)

On conifers .... ununguis, coniferarum (pp. 319, 328)

On other hosts . . .

. . yothersi, punicae, mangiferus, peronis (pp. 330, 335, 336)

Body with dorsal setae broadened proximally and strongly
tapering distally; integumentary striae longitudinal between
third pair of dorsocentral hysterosomals (Peruvianus Group)

. peruvianus (p. 342)

Body with dorsal setae not acutely tapering from an obviously
widened base; integumentary striae transverse between third

pair of dorsocentral hysterosomals . 14

Hysterosoma with integumentary striae longitudinal caudad
of inner sacrals . 15

Hysterosoma with integumentary striae transversely parallel
between inner and outer sacral setae (Pritchardi Group). . 16

Peritreme ending in a simple bulb (Pratensis Group) .

. stickneyi, gramineus, pratensis,

. . modestus, indicus, sacchari (pp. 344, 347, 349, 354, 355)

Peritreme retrorse distally (McGregori Group) .

. mcgregori (p. 359)

Peritreme retrorse distally . biharensis (p. 364)

Peritreme straight distally, ending in a simple bulb .

. * . . o . . .pritchardi, propetes (pp. 365, 366)

Males

1.

Aedeagus bent ventrad; tarsus 1 with not more than a single
tactile seta on venter just distad of duplex setae. ... 2

275

Subfamily T etranychinae lierlese

1.

2.(1).

2.(1).

3.(2).

3. (2).

4. (3).

4. (3).

5. (4).

5. (4).

6. (5).

6.(5).

n

(

(6).

7.(6).

8.(3).

8.(3).

Aedeagus bent dorsad, although the distal end may be directed
ventrad; tarsus 1 with two tactile setae on venter just distad
of duplex setae . 21

Body with dorsal setae obviously widened proximally and
acutely tapering distally; tibia 1 with nine tactile setae;
empodium with three pairs of proximoventral hairs; on dicot¬
yledonous plants (Peruvianus Croup) . . peruvianus (p. 342)

Body with dorsal setae slender, not acutely tapering from
widened proximal portion; tibia 1 with six or seven tactile
setae; empodium usually with four to six pairs of proximo-
ventral hairs (Ununguis Group) . 3

b irst pair of dorsocentral hysterosomals shorter than interval

to second pair . 4

hirst pair of dorsocentral hysterosomals longer than interval
to second pair . 8

Tibia l with seven tactile setae; tarsus I with three tactile
setae proximad of duplex setae; on cypress (Boudreauxi Sub¬
group) . boudreauxi (p. 291)

Tibia I with five or six tactile setae; Tarsus 1 with one or
no tactile setae proximad of duplex setae; on pine (Subnudus
Subgroup) . 5

First pair of dorsocentral hysterosomals about one-half length
of interval to second pair, finely pubescent . pityinus (p. 290)
First pair of dorsocentral hysterosomals not over one-fourth
length of interval to second pair, coarsely pubescent . . 6

Dorsocentral hysterosomals with anterior pair much shorter
than posterior pair; aedeagus with ventrally directed portion
from two-thirds to as long as dorsal part of shaft ....

. milleri (p. 280)

Dorsocentral hysterosomals all similar in length; aedeagus
with ventrally directed portion about one-fourth as long as
dorsal portion of shaft . 7

Tarsi III and I\ much longer than tibiae III and IV , and grad¬
ually narrowing to distal end .... subnudus (p. 281)

Tarsi III and IV about as long as tibiae III and I\ , and abruptly

declivate over base of pretarsus .... cunliffei (p. 284)

Tibia I with six tactile setae (Aceris Subgroup) .... 9

Tibia I with seven tactile setae; on other hosts (Bicolor and
Ununguis Subgroups) . 10

276

Spider Mites

9.(8).

9. (8).

10. (8).
10.(8).

11.(10).

11.(10).

12.(10).

12.(10).

13.(12).

13. (12).

14. (13).

14. (13).

15. (14).

15. (14).

16. (15).

16. (15).

17. (16).

17. (16).

18. (17).

18. (17).

19. (18).
19.(18).

Body with dorsal setae very strong; anterior dorsal sensory
seta of tibia I about one fourth as long as dorsal tactile seta;

on oak and chestnut . endytus (p. 301)

Body with dorsal setae slender; anterior dorsal sensory seta
of tibia I about one half as long as dorsal tactile seta; on maple
. aceris (p. 297)

On conifers . 11

On other hosts . 12

Aedeagus with bent portion ventrally directed and tapering

. ununguis (p. 319)

Aedeagus with bent portion directed caudoventrally and abrupt¬
ly truncate at tip . coniferarum (p. 328)

Duplex setae with proximal member of each pair nearly as

long as distal member . platani (p. 304)

Duplex setae with proximal member of each pair greatly shorter
than distal member . 13

Hysterosoma with outer sacrals much shorter than inner sacrals

. ilicis (p. 305)

Hysterosoma with outer sacrals more or less similar in length
to inner sacrals . 14

Aedeagus with distal bend as long as dorsal margin of shaft,
the distal half of the bend very slender . . yothersi (p. 330)

Aedeagus with bent portion much shorter than shaft ... 15

Bent portion of aedeagus much wider than long ....

. peronis (p. 336)

Bent portion of aedeagus longer than wide ...... 16

Aedeagus gradually narrowing distally . 17

Aedeagus with distal end abruptly narrowed . 20

Bend of aedeagus widened and with dorsocaudal portion of

bend flattened . newcomeri (p. 312)

Bend of aedeagus not widened and with dorsocaudal portion

evenly curved . 18

Aedeagus with bent portion at right angle to shaft ... 19
Aedeagus with bent portion forming an acute angle with shaft
. mangiferus (p. 330)

Bent portion of aedeagus sigmoid, the tip curved slightly

caudad . viridis (p. 311)

Bent portion of aedeagus with tip directed ventrad
. coffeae (p. 315)

Subfamily l'etranychinae Bcrlese

20.(16).

20.(16).

21.(1).

21.(1).

22.(21).

22.(21).

23.(22).

23. (22).

24. (23).

24. (23).

25. (23).

25. (23).

26. (25).

26. (25).

27. (21).

27. (21).

28. (27).

28. (27).

29. (28).
29.(28).

Aedeagus with bent portion forming a right angle with shaft

. punicae (p. 335)

Aedeagus with bent portion forming an obtuse angle with shaft
. bicolor (p. 308)

larsus 1 with proximoventral empodial appendages forming a
pair of empodial spurs; on monocots, mostly grasses (Prutensis

Group) . 22

larsus 1 with three pairs of proximoventral hairs on empodium;
on other hosts . 27

Aedeagus with distal end strongly sigmoid, the S-shaped portion

without obvious enlargement . sacchari (p. 355)

Aedeagus with distal end enlarged, not sigmoid .... 23

Knob of aedeagus about one-third as long as dorsal portion

of shaft . 24

Knob of aedeagus not over one-fourth as long as dorsal portion
of shaft . 25

Axis of knob of aedeagus forming about a 45-degree angle

with axis of shaft . gramineus (p. 347)

Axis of knob of aedeagus forming obviously less than a 45-
degree angle with axis of shaft, and knob more strongly

enlarged . stichneyi. (p. 344)

Knob of aedeagus about twice as wide as stem of knob .

. pratensis (p. 349)

Knob of aedeagus less obviously widened . 26

Aedeagal knob with axis parallel to axis of shaft

. modestus (p. 355)

Aedeagal knob with axis forming an angle with axis of shaft

. indicus (p. 354)

Aedeagus with terminal portion drawn out into a very slender

stylet (McGregori Group) . mcgregori (p. 359)

Aedeagus with distal end forming an acute angulation

(Pritchardi Group) . 28

Barb of aedeagus terminating above level of axis of shaft;

peritreme retrorse distally . biharensis (p. 364)

Barb of aedeagus with tip projecting into level of axis of shaft;
peritreme with a simple bulb at distal end . 29

Aedeagus with distal enlargement slightly angulate on dorsal
side, the distal end straight .... pritchardi (p. 365)

Aedeagus with distal enlargement strongly curved on dorsal
side, the distal end curved ventrad . . . propetes (p. 366)

278

Spider Mites

Fig. 227. Oligonychus milleri : dorsal aspect of female, Pomona Park, Florida.

Ununguis Group

Adults of the Ununguis Group may be recognized by having only
six or seven tactile setae on tibia I ( Oligonychus cunliffei is an ex¬
ception in that there are only five such setae). Tarsus I bears from
one to four tactile setae proximal to the duplex setae, and a single
tactile seta on the venter of the segment near or beyond the duplex
setae (except in 0. perditus where there are two such setae). There
are from four to six pairs of proximoventral setae on the empodium,

279

Subfamily T etrany chinae Herlese

Fig. 228. Oligonychus milleri : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

except on tarsus I of the male where there are often only three pairs.
The aedeagus bends ventrad as found otherwise in the genus only in
the Peruvianus Group. The integumentary striae of the adult female

280

Spider Mites

Fig. 229. Oligonychus milleri : A.) empodium I of male; B.) empodium IV
of male; C.) empodium I of female; D.) empodium II of female.

are transverse throughout the dorsocentral area of the hysterosoma.

Members of the Ununguis Group are ordinarily found on trees and
shrubs.

Oligonychus milleri [McGregor), new combination
(Figures 227, 228, 229, 230)

P aratetranychus milleri McGregor, 1950, Amer. Midi. Nat., 44: 343.
Types : males and females, Placerville, California, on Pinus
ponderosa; in the U. S. National Museum.

Adults of Oligonychus milleri may be recognized by having the
dorsocentral hysterosomals successively increasing in length, the
first pair being very short, the second pair longer, and the third pair
much longer than the first.

The aedeagus is also distinctive among the Subnudiis Subgroup
(tibia I with six tactile setae and tarsus I with one tactile seta proximal
to duplex setae) in that the distal end is very long, from two-thirds
to as long as dorsal portion of shaft, and it 'narrows evenly from a very
broad curvature. There is no geographical correlation with the compar¬
ative length of the turned down portion of the aedeagus, nor with
variations in the length of the dorsal seta of the body.

Specimens examined other than the types, are from El Cerrito, Cali¬
fornia (A. E. Pritchard), on pine; Coeur d’Alene, Idaho (J. C. Evenden),
on ponderosa pine; Logan, Utah, on scots pine; Lakewood, Wisconsin
(II. E. Mill iron), on jackpine; Coushaeta, Louisiana (L. D. Newson),

281

Subfamily I etrany chinae Berlese

on loblolly pine; Bryceland, Louisiana (L. 1). Newsom), on pine; Pomona
1 ark, Florida (0. 1). Link), on pine; Lake Placid (Arclibold Foundation)
anil St. Petersburg, Florida (L. \\. Baker), on pine; Durham, North
Carolina (A. F.. Pritchard), on pine; and Rehobeth Beach, Delaware
(L. \\. Baker), on pine. McGregor also recorded specimens from Arizona
and V irginia, on pine.

01 igonychus subnudus (McGregor), new combination
(Figures 231, 232, 233)

Paratetranychus subnudus McGregor, 1950, Amer. Midi. Nat., 44: 355.
Types: males and females, Oxnard, California, on pine; in the
U. S. National Museum.

Adults of Oligonychus subnudus may be recognized by having all
the dorsocentral hysterosomals very short and more or less similar
in length, together with having the tarsi, especially Ill and IV, slender
and longer than the tibiae.

Differences in the shape and length of the lateral and caudal setae
of the body of specimens studied indicate considerable variation, or
else that a species complex is involved. In typical specimens of 0.

subnudus (coastal California), the
dorsolateral hysterosomals and
humerals are rodlike, scarcely longer
than the dorsocentral hysterosomals,
but the outer pair of sacrals are
obviously longer than the inner pair.
Specimens from inland southern Cali¬
fornia exhibit dorsolateral hystero-
somal setae that are tapering and
much longer than the dorsocentrals,
the humerals being even longer; and
the dorsocentrals are also tapering.

The stylophore is deeply emarginate
distally in most of the specimens
studied, but it is only slightly cleft
or else broadly convex in specimens
studied from the interior of southern
California.

Fig. 230. Oligonychus milleri: The aedeagus is distinct from

aedeagus. that of Oligonychus milleri in that

282

Spider Mites

Fig. 231. Oligony chus subnudus : dorsal aspect of female, Yakitna, Washington.

the ventrally bent distal portion is not over one-fourth as long as the
dorsal portion of the shaft, and the distal end is acuminate and slightly
sigmoid. Variation in the comparative length and the curvature of the
bent distal portion is evident.

Specimens examined, except for the types, are from Richmond,
Berkeley, Oakland, Hayward, Monterey, Julian, and Keen Camp, Cali¬
fornia (A. E. Pritchard), on pine; Mountain View, California (M. Klaich),
on Monterey pine; Grant Grove, California (A. E. Pritchard), on red
fir; and Yakima, Washington (E. W'. Baker), on pine.

283

Subfamily Tetranychinae Berlese

Fig. 232. Oligonychus subnudus: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

284

Spicier Mites

01 igonychus hondoen si s (Ehara ), new combination

? Teramychus sp. ? (partim), Niijima, 1903, Textb. Jap. Forest Protect.,
p. 335, fig. 51.

? T etranychus sp. (partial), Niijima, 1923, Textb. Forest Protect., new
ser., vol. 1, p. 339, fig. 106; iVlatsushita, 1948, Textb. Forest
Pests, p. 401; Yamamoto, 1948, Textb. Forest Protect., p. 137.

P aratetranychus hondoensis Ehara, 1954, Annotat. Zool. Jap. 27(2):

102, 103. Types: Males and females, Sibusawa, Japan, on

Cryptomeria japonica; in Zoological Institute, Faculty ofScience,
Hokkaido University, Japan.

Oligonychus hondoensis is related to 0.
subnudus by the type of aedeagus, and the
dorsal setal structure of the female. It
is differentiated by having the first two pairs
of propodosomal setae and the humeral setae
quite long in the female, and in having com¬
paratively long dorsal body setae in the
male.

Fig. 233. Oligonychus
subnudus : aedeagus.

Oligonychus cunliffei Pritchard and Baker , new species
(Figures 234, 235, 236, 237)

Oligonychus cunliffei is closely allied to 0. subnudus and similarly
possesses very short dorsocentral hysterosomals. It differs, however,
in that all of the tarsi are short and stubby, and tarsus I lacks the
tactile seta proximad of the duplex setae. The body size is also con¬
siderably smaller.

This species is known only from Florida, on pine.

Female. — Palpus with terminal sensillum shorter than the dorsal,
fusiform seta. Stylophore broadly rounded anteriorly and slightly
emarginate medially. Peritreme straight distally. Tibia I with five
tactile and one sensory setae; tarsus I very short, abruptly declivate
beyond duplexes, with a single sensory seta proximoventral to duplexes,
and with a single tactile seta just beyond the duplexes before the
terminal setae of the tarsus; empodial claw very short, strongly hooked,
shorter than the three pairs of proximoventral hairs. Tibia II with four
tactile setae. Propodosoma with dorsal setae setiform, much shorter
than intervals between them, the second pair shorter than first and
third pairs. Hysterosoma with dorsocentrals similar in length and much

285

Subfamily Tetranychinae Herlese

Fig. 23 k Oligonychus cunliffei: dorsal aspect of female.

286

Spider Mites

Fig. 235. Oligonychus cunliffei : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

shorter than intervals between them, the first and second dorsolaterals
similar; humerals, third dorsolaterals, sacrals, and clunals all consider¬
ably longer; para-anals similar to clunals. Length of body 320 p ,
including rostrum 380//; greatest width of body, 193 p.

287

Subfamily l ctrany chinae Herlese

Fig, 236. Oligonychus cunliffei : A.) empodium I and tip of palpus
of female; B.) empodium I and tip of palpus of male.

Fig. 237. Oligonychus cunliffei : aedeagus.

l/olotype. — Female, St. Petersburg, Florida, June 27, 1952, (E. W.
Maker), on Pinus palustris ; type no. 2139 in the U. S. National Museum.
Paratypes . — Five females, St. Petersburg, Florida, June 27, 1952 (E. Vi.
Baker), on pine; 4 females, Pomona Park, Florida (0. D. Link), on pine;
1 female, Lake Placid, (Archbold Foundation), Florida, July 1952, (E. ft.
Baker), on pine. The male has been misplaced.

This species is named in honor of Frederick Cunliffe, of the Pinellas
Biological Laboratory, St. Petersburg, Florida, because of his keen
interest in advancing knowledge of plant-feeding mites.

288

Spider Mites

Fog. 238. Oligonychus pityinus: dorsal aspect of female.

01 igonychus brevipilosus ( Zacher ), new combination

Paratetranychus brevipilosus Zacher, 1932, Zool. Anz., 97: 179; Reck,
1950, Trudy Inst. Zool. Akad. Nauk S.S.R., 9: 126. Types :
females, Baden, Germany, on conifers; possibly in the Zacher
collection.

289

Subfamily Tetrany chinae Herlese

Fig. 239. Oligonychus pityinus: above, tibia and tarsus I of female;
below, tibia and tarsus II of female.

The photograph and drawings of the female presented by Zacher
indicate that this species is similar to Oligonychus subnudus
(McGregor).

This species is known only from the types from Germany, on pine,
and from Reek’s record from Georgia, S.S.R., on pine.

Oligonychus picei (Canestri ni ), new combination

Tetranychus picei Canestrini, 1889, Atti. Reale 1st. Veneto Sci. Let.
Arti (ser. 6), 7: 502. Described from specimens from Trentino,
Italy, on spruce.

Although Berlese (1894) and Geijskes (1939) considered Tetranychus
picei to be a synonym of Oligonychus minimus, this synonymy is not
accepted because of the difference in type hosts, and the longer dorsal
setae of the body in picei.

290

Spider Mites

Fig. 240. Oligonychus pityinus: above, tibia and tarsus I of male;
below, tibia and tarsus II of male.

A study of three type females in the Berlese collection indicates that
picei is closely allied to subnudus. The dorsal setae of the body are
short and lanceolate but not much shorter than the intervals between
them longitudinally.

01 igonychus pityinus Pritchard and Baker, new species
(Figures 238, 239, 240, 241)

1 he adults of Oligonychus pityinus may be recognized by having
the first pair of dorsocentral hysterosomals from one-half to three-
fourths as long as the interval to the second pair, tapering, and sparsely

291

Subfamily T etrariy chinae Herlese

Fig. 241. Oligonychus pityinus :
aedeagus.

pubescent. 1 he second ami third pair
of dorsocentral hysterosomuls .ire
similar. The fore tibia bears six
pairs of tactile setae, and the fore
tarsus bears a single tactile seta
as in 0. milleri and 0. subnudus.

The aedeagus resembles that of 0.
subnudus in that the distal, ventrally
directed portion is tapering and somewhat curved, but it is only about
one-half as long as the dorsal portion of the shaft.

Ibis species is known only from southern California, on pine.

Male. — Palpus with terminal sensillum much shorter than fusiform
sensillum, about as long as wide. Peritreme straight distally. Tibia 1
with five tactile and four sensory setae; tarsus I with one tactile and
three sensory setae proximal to the duplexes and with a single tactile
seta ventrally at the level of the duplexes; empodial claw short, slightly
shorter than the four pairs of proximoventral hairs. Tibia 11 with four
tactile setae. Propodosoma with dorsal setae slender, tapering, finely
pubescent, about as long as longitudinal intervals between them. Hyster-
osoma with dorsal setae similar to dorsal propodosomals; para-anals
similar to clunals. Aedeagus with distal one-half bent sharply ventrad
at a right angle, the distal portion with caudal face curved and tapering
to near the tip. Length of body 233 p ; including rostrum 300 p .

Female. — Similar. Terminal sensillum of palpus larger. Stylophore
broad and very slightly emarginate anteromedially. Tibia I with five
tactile and one sensory setae; tarsus I with one tactile and one sensory
setae proximal to duplexes. Length of body 333 p, including gnathosoma
433 p; greatest width of body 233 p.

Holotype. — Male, Big Pine, Inyo County, California, May 24, 1951
(A. E. Pritchard), on Pinus monophylla; type no. 2140 in the U. S.
National Museum. P aratypes. — Six males, 4 females, Big Pine, Cali¬
fornia, May 24, 1951 (A. E. Pritchard), on Pinus monophylla.

Oligonychus boudreauxi Pritchard and Baker, new species
(Figures 242, 243, 244, 245)

Adults of Oligonychus boudreauxi may be distinguished by having
the first pair of dorsocentral hvsterosomals much shorter than the
interval to the second pair, together with having seven tactile setae
on tibia I and three tactile setae proximal to the duplex setae on tarsus
I. The ventrally directed end of the aedeagus is tapering, slightly

292

Spider Mites

Fig. 242. Oligony chus boudreauxi: dorsal aspect of
female, Leland, Mississippi.

293

Subfamily 1 etrany chinae Berlese

curved, and not over one-fourth as long as the dorsal portion of the
shaft.

This species is known to occur only in the southeastern United
States, on cypress.

] Idle. — Palpus with terminal sensillum very small. Peritreme straight
distall y, slightly enlarged at distal end. Tibia I with seven tactile

294

Spider Mites

Fig. 244. Oligonychus boudreauxi : above, empodium I
of male; below, empodium I of female.

Fig. 245. Oligonychus boudreauxi : aedeagus.

295

Sub family Tetrany ch inae H t-rl es e

Fig. 246. Oligonychus aceris : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; C.) tibia and tarsus II
of male.

296

Spider Mites

Fig. 247. Oligonychus aceris : A.) empodium III of male; R.) empodium
I of male; C.) empodium III of female.

and three sensory setae; tarsus I with three tactile and three sensory
setae proximal to duplexes and a single tactile seta ventrally just
distal to duplexes; empodial claw I slender, curved, longer than the
four (sometimes apparently three) pairs of proximoventral hairs. Tibia
II with four tactile setae. Propodosoma with dorsal setae slender,
tapering, rather coarsely pubescent, the first pair longer than the interval
to the second, the third pair similar, the second pair considerably
shorter. Hysterosoma with dorsocentrals gradually increasing in length,
the first pair being less than one-half as long as interval to second
pair, the third pair reaching the inner sacrals; dorsolaterals, humerals,
and sacrals as long as third pair of dorsocentrals. Aedeagus with distal
one-fourth directed ventral, slightly curved and tapering. Length of
body 233p, including rostrum 282p; greatest width of body, 120g.

Female. — Similar. Terminal sensillum of palpus larger. Stylophore
comparatively broad, distinctly emarginate mediocephalically. Tibia
1 with seven tactile and one sensory seta; tarsus I with three tactile

297

Subfamily I etranychinae Herlese

and one sensory seta proximal to duplexes. Length of body 366 p ,
including gnatbosoma 400 p; greatest width of body 200 p .

Holotype. — Male, Baton Rouge, Louisiana, May 29, 1953 (R. W.
Burrell), on cypress; type no. 2141 in the U. S. National Museum.
Paratypes. — Five males, 20 females, Baton Rouge, Louisiana, jMay
29, 1953 (R. W. Burrell), on cypress; 3 males, 5 females, Baton Rouge,
Louisiana, June 5, 1951 (L. D. Newsom), on cypress; 1 male, 7 females,
Leland, Mississippi (C. J. flay), on T axodium distichum.

This species is named in honor of H. B. Boudreaux, an outstanding
student of spider mites of the southeastern United States.

01 igonychus aceris ( Shimer ), new combination
(Figures 246, 247, 248)

Acarus aceris Shimer, 1869, Trans. Amer. F.nt. Soc., 2 : 320. Described
from specimens from Illinois, on maple.

298

Spider Mites

Fig. 249. Oligonyclius endytus : dorsal aspect of female.

Subfamily fetrany chinae Berlese

Fig. 250. Oligonychus endytus: above, tibia and tarsus I of
female; below, tarsus II of female.

Tetranychus aceris, Banks, 1907, Proc. U. S. Natl. Mus., 32(1553):
598.

Adults of Oligonychus aceris may be readily recognized by having
only six tactile setae on tibia I, together with having the dorsal setae
of the body long and slender, set on small tubercles. The fore tarsus
bears three tactile setae proximal to the duplex setae, and the empodial
claw is very long.

In contrast to other members of the Ununguis Group that feed on
broad-leaved plants, Oligonychus aceris is found primarily on the
lower surface of the leaf. Adult females are straw colored with large
black markings.

300

Spider Mites

Fig. 251. Oligonychus endytus : above, tibia and tarsus I
of male; below, tibia and tarsus II of male.

This species is widespread and often abundant on maples in the
eastern United States. Specimens have been studied from Ithaca, New
\ ork (J. G. Matthysse), on maple; New \ ork City (from Philip Garman)
on sugar maple; Princeton, New Jersey (E. G. Brewer) on red maple;
Washington, D. C. (E. W. Baker), on red maple; Durham, North Carolina
(A. E. Pritchard), on maple; Vincennes, Indiana (S. A. Summerland)
on maple; Lawrence, Kansas (R. E. Beer), on maple; and \akima,
Washington (E. J. New-comer), on maple.

301

Subfamily T etruny chinae Berlese

Fig. 252. Oligony chus endytus : above, empodium I of male
below, empodium I of female.

01 igonychus endytus Pritchard and Baker, new species
(Figures 249, 250, 251, 252, 253)

Adults of Oligonychus endytus may be readily recognized by the
very long and stout dorsal setae that are borne on strong tubercles.

This species is known only from California, on valley oak and
chestnut.

Male. — Palpus with terminal sensillum very short and conical.
Peritreme straight and simple distally. Tibia I with six tactile and
three sensory setae; tarsus 1 with three tactile and three sensory setae
proximal to duplexes; with a single tactile seta ventrad of duplexes;
empodial claw moderately long and slender but shorter than the three
pairs of proximoventral hairs. Tibia II with five tactile setae. Dorsal
setae of the body moderately stout, narrowing, borne on tubercles, and
longer than longitudinal intervals between their bases; second dorsal
propodosomal much larger than first or third: humerals somewhat shorter

302

Spider Mites

Fig. 253. Oligonycnus endytus: aedeagus.

than dorsal hysterosomals except for the shorter clunals and outer
sacrals. Aedeagus with distal one-third bent ventrad, the terminal
portion narrowed to an acute tip. Length of body 266 p; including gnat bo-
soma 313 p.

Female. — Terminal sensillum of palpus broader and larger. Stylo-
phore moderately broad, somewhat emarginate anterodistall v. Tibia
I with six tactile and one sensory seta; tarsus I with three tactile and
one sensory setae proximal to duplexes; empodial claw with four pairs
of proximoventral setae. Body with dorsal setae stronger. Length of
body 286p, including gnathosoma 328p; greatest width of body 233 p.

Holotype. — Male, Berkeley, California, October 20, 1951 (W. C.
Bentinck), on oak; type no. 2142 in the U. S. National Museum.
Paratypes. — Four males, two females, Berkeley, California, October
20, 1951 (W. C. Bentinck), on oak; 1 female, Berkeley, California,
October 4, 1949 (A. E. Pritchard), on valley oak; 4 males, 2 females,
1 nymph, Lafayette, California, September 10, 1952 (A. D. Borden),
on chestnut.

According to A. D. Borden, this species is a serious pest of chestnut.
Deciduous oaks on the U niversity of California campus are only moder¬
ately infested. The mites feed primarily on the upper surfaces of the
leaves, as is characteristic of most other members of the genus.

Subfamily Tetranychinac Hrrlt-se

Fig. 254. Oligonycnus platani: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

304

Spider Mites

Fig. 255. Oligonychus platani: above, empodium I
of male; below, empodium I of female.

Oligonychus platani (McGregor), new combination
(Figures 254, 255, 256)

Paratetranychus platani McGregor, 1950, Amer. Midi. Nat., 44: 349.
Types: males and females, Davis, California, on sycamore; in
the U. S. National Museum.

Adult females of Oligonychus platani have seven tactile setae on
tibia 1 and three tactile setae proximad of the duplex setae on tarsus
I. Adults are distinctive in that the proximal member of each pair of
duplex setae is nearly as long as the distal member. The aedeagus
closely resembles that of Oligonychus viridis : the distal one-fourth
bends abruptly ventrad, and the distal end is slender.

California females have one sensory seta proximally on tarsus 1;
whereas Mexican specimens bear two or three such setae. The color

305

Subfamily T etrany chinae Berlese

of the adult female in life is somewhat
greenish with pronounced black spots.
The eggs are pale, radially striate
dorsally, and with a dorsal stipe.

It is possible that there are two
species or subspecies involved in this
taxonomic category. Oli gonychus
platani is a constant, serious pest of
the sycamore in the hot, interior valleys
of California. Specimens have not been
collected from London plane trees on
the coastal area of California, even
though similar specimens are common
on and sometimes a serious pest in
this area on broad-leaved evergreens.

Specimens examined are from Davis,
Tracy, Delano, Madera, and Bakers¬
field, California (A. E. Pritchard),
on London plane tree; Berkeley,
California (A. E. Pritchard), on loquat,
toyon, coast live oak, and valley
oak; Redwood City and Palo Alto,
California (A. E. Pritchard), on coast
live oak; Niles, California (A. E.
Pritchard), on cork oak; Sacramento,
California (A. E. Pritchard), on cork
oak; Glendora, California (J. W. Mac-
Swain), on toyon; Riverside, California
(A. E. Pritchard), on pyracantha; and Mexico (J. A. Baker, at El Paso,
Texas, quarantine), on oak.

Fig. 256. Oligony chus platani:
aedeagi.

01 igonychus ilicis (Me Gregor), new combination
(Figures 257, 258, 259)

T etrany chus ilicis McGregor, 1917, Proc. U. S. Natl. Mus., 51(2167):
586. Types: males and females, Batesburg, South Carolina, on
American holly; in the U. S. National Museum.

Paratetranychus ilicis, McGregor, 1919, Proc. U. S. Natl. Mus.,
56(2303): 673; Garman, 1940, Bui. Conn. Agr. Exp. Sta. 431:
78; McGregor, 1950, Amer. Midi. Nat., 44: 340.

306

Spider Mites

Fig. 257. Oligonychus ilicis : dorsal aspect of
female, North Carolina, holly.

The adult female of ilicis belongs to that species subgroup of the
genus Oligonychus in which the fore tibia bears seven tactile setae
and the fore tarsus three tactile setae proximal to the duplex setae.
Adults are distinct from other members of this subgroup (as well as the

Subfamily Tetranychinae Htrlt'se

Fig. 258. Oligonychus ilicis: A.) tibia and tarsus I of female; B.) tibia and
tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II of male.

Tnunguis Subgroup) in that the outer sacral setae are obviously smaller
than the inner sacrals. The body of the female is basically purplish
or reddish, paler anteriorly and with a paler spot medially, and the
dorsal setae are borne on small tubercles (sometimes not evident in
mounted specimens). The aedeagus closely resembles that of Oligony-
chus platani.

308

Spider Mites

Fig. 259, Oligonychus ilicis : empodium of female and aedeagus.

Oligonychus ilicis is particularly a pest of camellias and azaleas
in the southeastern United States, although its native home is probably
the Far East. English and Turnipseed (1940) have discussed its im¬
portance in Alabama.

Specimens, other than the types, that have been studied are from
Brookville, New York (J. Matthysse), on laurel; Tareytown, New \ork
(J. Matthysse), on camellia; Patchoque, Long Island, New ^ ork (C. V.
Johnson), on camellia; Raleigh, North Carolina (C. F. Smith), on holly
and azalea; Durham, North Carolina (A. E. Pritchard), on camellia;
Lake Co., Ohio (R. Neiswander), on boxwood; Baton Rouge, Louisiana
(J. Roussell), on camellia; Hayward and San Leandro, California
(A. E. Pritchard), on camellia and azalea; and Kyushu, Japan
(M. Tanaka), on rhododendron.

Oligonychus bicolor {Banks), new combination
(Figures 260, 261, 262)

T etranychus bi color Banks, 1894, Trans. Amer. Ent. Soc., 21: 218;
Banks, 1900, U. S. Dept. Agric. Div. Ent. Tech. Bui., 8: 72;
Types: females, Sea Cliff, New \ork, on oak; in the U. S. Na¬
tional Museum.

Paratetranychus bicolor , McGregor, 1919, Proc. U. S. Natl. Mus., 56
(2303): 675; Carman, 1940, Bui. Conn. Agr. Exp. Sta., 431: 77;
McGregor, 1950, Amer. Midi. Nat., 44: 334.

The adult female of Oligonychus bicolor resembles that of O. viridis,
O. newcomeri, and 0. coffeae in that the fore tibia bears seven
tactile setae and the fore tarsus bears three tactile setae proximad
of the duplex setae. The female resembles that of 0. newcomeri and
O. coffeae in that it is reddish in basic color.

309

Subfamily T e trany chinae li frit's?

Fig. 260. Oli gonyciius bicolor: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

310

Spider Mites

Fig. 261. Oligonychus bicolor : A.) empodium 1 of male; B.)
Empodium III of male; C.) empodium IV of female.

The aedeagus of this species is distinctive in that the distal end
of the ventrally bent portion is very abruptly narrowed and the bend
forms an obtuse curvature with the shaft.

Specimens of Oligonychus bicolor that have been studied by us
are all from oak or chestnut in the eastern United States, and severe
damage may be caused to shade trees. Series examined are from Ithaca,
New York (J. G. Matthysse), on oak; Hamden, Connecticut (Philip
German), on red oak; Washington, D. C. (E. W. Baker), on red oak;
Durham, North Carolina (A. E. Pritchard), on willow oak and white
oak; and Lawrence, Kansas (R. E. Beer), on pin oak.

311

Subfamily I etrany chinae Rerlese

Fig, 262, Oligonychus bicolor, aedeagus, Kansas.

01 igonychus viridis {Banks), new combination
(Figure 263)

1 etranychus viridis Banks, 1894, Trans. Amer. Ent. Soc., 21: 218.
Described from specimens from lexas, on pecan; of unknown
disposition.

Paraletranychus viridis, McGregor, 1919, Proc. U. S. Natl. Mus., 56
(2303): 671; McGregor, 1950, Amer. Midi. Nat., 44: 357.

1 he female of Oligonychus viridis closely resembles tliat of 0.
bicolor, 0. newcomeri, and O. coffeae. However, tlie basic color of
the body in life is greenish.

lhe aedeagus of Oligonychus viridis differs from those species
from which the females are morphologically indistinguishable in that
the portion bent ventrad tapers evenly to an acute tip, and it is sigmoid,
the distal end being somewhat caudally directed.

Specimens have been studied from Baton Rouge, Louisiana (Hardwick),
on pecan: Keatchie, Louisiana (VL C. Pierce), on pecan; Albany, Georgia
(G. F. Moznette), on pecan: and Monticello, Florida (J. B. Gill), on
pecan.

312

Spider Mites

Fig. 263. Oligonychus viridis : tarsus IV of female and aedeagus.

01 igonychus newcomer/ (McGregor), new combination
(Figures 264, 265, 266, 267)

P aratetranychus newcorneri McGregor, 1950, Amer. Midi. Nat., 44: 345.
Pritchard and Baker, 1952, Ililgardia, 21(9): 261. Types : males
and females, Yakima, Washington,, on pear; in the U. S. National
Museum.

Adult females of Oligonychus newcorneri are reddish in basic color,
and they are indistinguishable from females of P. bicolor. The fore
tibia bears seven tactile setae, and there are three tactile setae proximad
of the duplex setae on tarsus I.

The aedeagus of Oligonychus newcorneri is distinctive in that it
is widened at the bend with the upper surface straight on the dorso-
caudal portion of the bend, and it is acutely tapering distally.

Specimens studied include the types and topotypes, Yakima, Wash¬
ington (R. W. Burell), on pear.

313

Subfamily Tetranychinae Herlrse

Fig. 264. Oligony chus newcomeri : dorsal aspect of female.

314

Spider Mites

Fig. 265. Oligonychus newcomeri: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; 0.) tibia and tarsus II
of male.

3ir>

Subfamily I etranychinae Herlese

Mg. 266. Oligonychus neucomeri: empodium IV of female.

01 igonychus co ffeae ( N ietner), new combination
(Figures 268, 269)

Acarus coffeae Nietner, 1861, Observ. Enem. Coffee Tree Ceylon;
Nietner and Green, 1880, Coffee Iree Enemies, pp. 19, 20.
Described from specimens from Ceylon, on coffee trees.

7 etranychus bioculatus Wood-Mason, 1884, Hep. Tea-Mite Tea-Dug
Assam, p. 1. Described from specimens from Ceylon, on tea.
A ew synonymy.

P arat etranychus bioculatus, Daker and Pritchard, 1953, Hilgardia,
22(7): 213.

Oligonychus meru'ei 1 ucker, 1926, Ent. Mem. Dept. Agric. Pretoria,
5: 6. De scribed from males and females, Stanger, Natal, on tea
plants. New synonymy.

Our identification of Oligonychus bioculatus is based on topotypes
submitted by courtesy of C. A. Loos.

We have not seen the 1861 publication in which Nietner described
Acarus coffeae, but the description in the second edition, 1880, is
probably identical. Die description allows reference of the species
to the genus Oligonychus. Although we have not seen specimens from
coffee, it is assumed that they would represent the same species that
occurs commonly in Ceylon on tea.

The female bears seven tactile (and one sensory) setae on tibia I
and three tactile (and one sensory) setae proximal to the duplex setae
on tarsus 1. This sex is morphologically indistinguishable from Oligony¬
chus bicolor, 0. viridis, and 0. neu comeri.

However, the aedeagus differs from these three species in that the
distal bend is at right angles to the shaft and it gradually narrows
to a slender distal end. The tip is truncate. In specimens from Florida,
on Melaleuca, the bent portion appears somewhat shorter and more
pointed, but other Florida material is typical.

316

Spic/er Mites

Oligonychus merwei was described
from South Africa, on tea, the descrip¬
tion and figures obviously referring to
a member of the Ununguis Group. Speci¬
mens have been studied by us that are
from South Africa, on Virginia creeper,
and they are indistinguishable from 0.
coffeae. Because 0. coffeae is thus
known to occur in South Africa and
because it is regarded as occurring on
tea, 0. meruei is here considered to be
a synonym.

Specimens studied by us that are
referred to this species are from Ceylon
(C. A. Loos), on tea; Pretoria, Transvaal,
South Africa (E. K. Hartwig), on P arth-
enocissus quinque folia', Brisbane, Aus¬
tralia (E. H. Derrick), on Quisqualis
indie a; Gainesville, Florida (L. C.
Kuitert), on camellia; and Richmond,
Florida (F. G. Butcher), on Melaleuca sp.

Oligonychus terminalis ( Sayed ), new combination

P aratetranychus terminalis Sayed, 1946, Bui. Soc. Fouad ler Ent.,
30: 94. Types: males and females, Egypt, on Mangifera indica,
Terminalia sp., Eugenia gambolana, and Vitis vinifera; probably
in the collection of M. T. Sayed.

Sayed’s original description of terminalis indicates that this species
belongs to the Ununguis Group. The figure of the aedeagus is not
sufficiently detailed, however, to give positive identification. Ihe
figure of tarsus I of the female, together with figures of the dorsal
chaetotaxy, indicates that this species is possibly a synonym of Oli¬
gonychus coffeae.

Oligonychus perditus Pritchard and Baker, new species
(Figures 270, 271, 272, 273)

Oligonychus perditus may be differentiated from all other members
of the Ununguis Group by possessing two tactile setae ventrally just

317

Subfamily T etrany chinae litrlese

Fit*. 268. Oligonychus coffeae: A.) tibia and tarsus I of female; P.) tibia
and tarsus II of female, with enlargement of empodium; C.) tibia and tarsus I
of male; H.) tibia and tarsus II of male.

318

Spider Mites

beyond the duplexes on tarsus I.
The aedeagus is of the ununguis
type, but it is distinctive in having
a mediodorsal notch near the base
of the external portion of the shaft.

This species is known only
from Japan where it is apparently
common on cupressaceous conifers.

Male. — Palpus with terminal

sensillum very small, about as long
as the fusiform dorsal rod. Peri-
treme straight distally, slightly
enlarged at tip. Tibia I with seven
tactile and four sensory setae;
tarsus I with three tactile and three
sensory -setae proximal to duplexes
and with a pair of tactile setae
ventrad of the duplexes. Tibia II
with five tactile setae. Empodial
claw slender, cultriform, about
as long as the five or six pairs
of proximoventral hairs. Dorsal
setae of body slender, tapering,
somewhat longer than longitudinal intervals between them. Aedeagus
with distal one-third bent abruptly ventrad, the distal end narrow; dorsum
of shaft with a conspicuous notch near base. Length of body 333 p,
including rostrum 410 p.

Female. — Similar. Terminal sensillum of palpus much larger than
fusiform rod. Stylophore slightly emarginate anteromedially. Tibia I
with seven tactile and one sensory setae; tarsus I with three tactile
and one sensory setae proximal to duplexes. Length of body 345 p,
including gnathosoma 433 p ; Greatest width of body 300 p.

Holotype. — Male, Japan, May 20, 1952 (E. I. Smith), at Seattle,
Washington quarantine, on juniper; type no. 2143 in tfie U. S. National
Museum. Paratypes. — Three males, 15 females, Japan, July 24, 1950
(at Seattle, Washington quarantine), on dwarf juniper; 2 males, Japan,
August 29, 1950 (C. V. Scott, at Seattle, Washington quarantine), on
juniper; 1 male, Japan, May 3, 1951 (Howard, at San Francisco, Cali¬
fornia quarantine), on Juniperus sp.; 11 females, Japan, May 20, 1952
(E. 1. Smith, at Seattle, Washington quarantine), on juniper.

319

Subfamily

1 etrany chi nae Herlese

Fig. 270. Oligony chus perditus : dorsal aspect of female.

01 igonychus ununguis ( Jacobi )

(Figures 274, 275, 276, 277)

T etrany chus ununguis Jacobi, 1905, Natunv. Zts. Land.-Forstw., 3:

239. Described from specimens from Dahlem, Germany, on spruce.

P arat etrany chus ununguis, Zac her, 1913, Mitt. kais. biol. Anst. Land.-
Forstw., 14: 39; Jragardh, 1915, Medd. Centralanst. Forsoksv.
jordbruksomr. Ent. Avdeln. 109 : 29, 57; Zactier, 1916, Mitt.*

320

Spider Mites

Fie. 271. Oligonychus perditus: A.) tibia and tarsus 1 of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

321

Subfamily I etrwiychinae Herlese

Fig. 272. Oligonychus perditus: A.) empodium I of male; 13.)
empodium I of female; C.) empodium IV of female.

kaiserl. biol. Anst. Land.-Forstw. , 16: 25; McGregor, 1919,

Proc. IL S. Natl. Mus., 56(2303): 669; Garnian, 1923, Bui. Conn.
Agr. Exp. Sta., 247: 340; Zaclier, 1921, Zts. ang. Ent., 7: 184;
Ryle, 1925, Quar. Jour. Forestry, Lond., 1925: 1; Hirst, 1924,
Ann. Mag. Nat. Hist. (ser. 9), 14: 526; Oudemans, 1931, Ent.
Her., 8(180): 277; Zaclier, 1932, Zool. Anz., 97: 180; Geijskes,
1939, Meded. Landbouwh. ^ageningen, 42(4): 34; Garnian, 1940,
Bui. Conn. Agr. Exp. Sta., 431: 80; McGregor, 1950, Amer.
Midi. Nat., 44: 356; Reck, 1950, Irudy Inst. Zool. Akad. Nauk
S.S.R., 9: 126.

Oligonychus ununguis , Hirst, 1^20, Proc. Zool. Soc. Lond. lf)20:59.

T etranychus uniunguis Ewing, 1917, Jour. Econ. Ent., 10: 497. Types:
females, Urbana, Illinois, on arbor vitae; in the U. S. National
Museum. \ ew synonymy.

322

Spider Mites

Neotetranychus uniunguis, McGregor, 1919, Proc. U. S. Natl. Mus.,
56(2303): 647.

Paratetranychus uniunguis, McGregor, 1950, Amer. Midi. Nat., 44: 356.
Oligonychus americanus Ewing, 1921, Proc. U. S. Natl. Mus., 59(2394):
660. Types: males and females, Saskatchewan, Canada, on
spruce; in the U. S. National Museum. New synonymy.
Paratetranychus americanus, McGregor, 1950, Amer. Midi. Nat., 44:
333.

Paratetranychus alpinus McGregor, 1936, Ann. Ent. Soc. Amer., 29:
770. Types: males and females, Camp Nelson, California, on
Libocedrus decurrens; in the U. S. National Museum. New
synonymy.

P aratetrany chus pini Hirst, 1924, Ann. Mag. Nat. Hist. (ser. 9), 14: 526.
Types: males and females, Oxshott, Surrey, England, on Pinus
sylvestris ; probably in the British Museum (Natural History).

The female of Oligonychus ununguis bears seven tactile (and usually
one sensory) setae on tibia I and four tactile (and usually one sensory)
setae proximal to the duplex setae on tarsus I. This sex is indistinguish¬
able from O. coniferarum, 0. mangiferus, 0. yothersi, O. punicae, and
0. peronis.

The aedeagus is distinctive among these species in that the bend
is at a right angle to the shaft and the bent portion tapers gradually
to an acute tip; no dorsal notch is present on the shaft. Ihe length
of the bent portion varies considerably, being from less than one-half
to nearly as long as the dorsal margin of the shaft. It is probable that
a species complex is involved, but no clear-cut morphological separa¬
tions are indicated, and no distributional pattern nor host relationship
is correlated.

That Oligonychus ununguis is ordinarily found only on conifers
has been demonstrated by extensive collecting in the San Francisco
Bay region where no morphologically similar species has ever been
found on hosts other than conifers.

In collections from Amherst,

Massachusetts, the only series
studied from spruce, the female
bears in addition to the normal num¬
ber of tactile setae, four sensory
setae proximally on tarsus I. The
additional setae are considered to
be a variation.

Fig. 273. Oligonychus perditus:

323

Subfamily 1 ctrany chinae Herlese

Fig. 274. Oligonychus ununguis: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II

324

Spider Mites

Fig. 275. Oligonychus ununguis: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II of
of male, all from Amherst, Massachusetts, spruce.

325

Subfamily I etranychinae lierlcsc

Fig. 276. Oligonychus ununguis: above, empodium I of male; below, empodium
of female, both from Coachella Valley, California.

Fig. 277. Oligonychus ununguis: left, aedeagus, Coachella Valley,
California; right, aedeagus, Amherst, Massachusetts.

In collections from Beltsville, Maryland, on pine, the only specimens
studied from this host, the females consistently bear only three tactile
setae proximal to the duplexes on tarsus I. These specimens could
represent a distinct species, but no other differences are apparent.
The striae in the area immediately anterior to the genital flap are trans¬
verse in the specimens from pine. These striae are usually longitudinal
in females from cupressaceous hosts, but they vary to being transverse.

Hirst gave the name pini to specimens from England, on pine, that
he had previously (1920) identified as Oligonychus ununguis. Specimens
later examined by Hirst (1924) from England, on spruce, were identified
as the ununguis of Tragardh, and pini was regarded as having the distal,
bent portion of the aedeagus as being less slender and drawn out. No

326

Spider Mites

Fig. 278. Oligonychus coniferarum: A.) tibia and tarsus I of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of male.

327

Su b furri ily I ft ran y ch in a e fi erlese

Fig. 279. Oligonychus coniferarum: A.) empodium I of male; R.)
empodium III of male; C.) empodium II of female.

otlier characters were given by liirst for differentiating the two species,
and t fie length of the dorsal setae of pini was not noted. Because the
comparative length of the distal bend of the aedeagus is here considered
to be variable, pini is considered to be a synonym. The figure given
by Hirst (1920) of the aedeagus of pini is more typical of ununguis
than that presented by Hirst (1924) for ununguis.

We have studied a large number of specimens collected from through¬
out the United States and many specimens from Europe that were
intercepted at American ports. Members of the Cupressaceae are among
the favorite hosts: Juniperus, Cupressus, Thuja, Chamaecyparis, and
Libocedrus. Spruce is reported to be a favorite host; and specimens
have been collected on redwood and sequoia in California.

328

Spider Mites

Oligonychus inouei ( Ehara), new combination

? Tetranychus sp. (partim), Harada, 1927, Principl. Forest Enem. Con¬
trol, p. 72; Inoue, 1942, Prakt. Anleit. f. Vorbeug. u. Vertilg. v.
biolog. Forstschad., p. 121, fig. 75; Matsushita, 1943, Textb.
Forest Rests, p. 403, fig. 187.

P aratetranychus inouei Ehara, 1954, Annotat. Zool. Jap. 27(2): 104-106.

Types : Males and females, Hokkaido, Japan., on Picen jezoensis
and Abies mayriana, and Mombetsu, Japan, on Abies mayriana ;
in Zoological Institute, Faculty of Science, Hokkaido University,
Japan.

Oligonychus inouei appears to be closely related to 0. ununguis by
reason of the dorsal setal pattern, tarsus I setal pattern of the female,
and aedeagus of the male.

Oligonychus coniferarum ( McGregor ), new combination
(Figures 278, 279, 280)

P aratetranychus coniferarum McGregor, 1950, Amer. Midi. Nat., 44:
338. Types: males and females, Glen St. Marys, Florida, on
arbor vitae; in the U. S. National Museum.

Fig. 280. Oligonychus coniferarum : aedeagus.

Oligonychus coniferarum differs from O. ununguis only in that the
aedeagus forms a short, truncate, caudolaterally directed bend.

1 his species was originally known from specimens collected in
Florida, but other specimens have been examined from Hrownsville,
Texas (R. Alexander), on arbor vitae; and Ysleta, Texas (P. Netterville),
on Pfitzer juniper. McGregor stated that “other conifers” are also hosts.

329

Subfamily 1 etranychinae Hrrlrse

Fig. 281. Oligonychus mangiferus: A.) tibia and tarsus I of female; R.) tibia
and tarsus 11 of female; Cl.) tibia and tarsus 1 of male; R.) tibia and tarsus II
of male.

330

Spider Mites

01 igonychus mangiferus ( Rahman and Punjab), new combination
(Figures 281, 282)

P aratetranychus mangiferus Rahman and Punjab, 1940, Proc. Indian
Acad. Sci. (ser. B), 11: 192. Described from males and females,
Lyallpur, India, on mango, grape, and Eugenia jambolana.

P aratetranychus insularis McGregor, 1950, Amer. Midi. Nat., 44: 341.
Types : males and females, Poamoho, Oahu, on mango; in the
U. S. Natio’nal Museum. New synonymy.

The female of Oligonychus mangiferus is indistinguishable from
other members of the Ununguis Subgroup, which is characterized by
having seven tactile setae on tibia I and four tactile setae proximal

to the duplexes on tarsus I. The aedeagus
is distinctive in that the bent portion
is small, triangularly tapering or nearly
so, and forming an acute angle with
the shaft.

The synonymy of insularis with
mangiferus is based on a similarity in
drawings of the aedeagus, and both were
described from the same hosts. There
are no tetranychids endemic to Hawaii,
and tropical Asia is probably the original
home of this mite.

Specimens studied by us, other than
the types, are from Honolulu, Hawaii
(F. S. Morishita), on mango; Mopulehu,
Malokai (F. S. Morishita), on mango;
Poamoho, Oahu (F. S. Morishita), on
Anona sp.; and Peru (at Houston, Texas
quarantine), on rose.

Fig. 282. Oligonychus
mangiferus : aedeagus.

Oligonychus yothersi (McGregor), new combination
(Figures 283, 284, 285)

Tetranychus yothersi McGregor, 1914, Ann. Ent. Soc. Amer., 7: 355.
Types: females, Orlando, Florida, on camphor; in the U. S.
National Museum.

P aratetranychus yothersi, Banks, 1915, U. S. Dept. Agric. Hep., 108:
37; McGregor, 1919, Proc. U. S. Natl. Mus., 56(2303): 676;

331

Subfamily 1 etrany chinae Berlt'sr

Fig. 283. Oligonychus yothersi : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

332

Spider Mites

Fig. 284. Oligonychus yothersi : empodia of female.

McGregor, 1941, Proc. Ent. Soc. Wash., 43: 86; McGregor, 1950,
Amer. Midi. Nat., 44: 358.

Oligonychus major Ewing, 1921, Proc. U. S. Natl. Mus., 59(2394): 660.
Types : males and females, Rockville, Maryland, on avocado;
in the U. S. National Museum. New synonymy.

Females of Oligonychus yothersi are indistinguishable from other
members of the Ununguis Subgroup — those having seven tactile setae
on tibia 1 and four tactile setae proximal to the duplex setae on tarsus
I. The number of sensory setae associated with these tactile setae
is subject to considerable variation: from one to four on tibia I and
from one to two on the proximal portion of tarsus I. Rarely only three
tactile setae are found proximally on tarsus I.

The aedeagus is very distinctive in that the bent portion is as long
as the dorsal part of the shaft and the distal one-half of the hook is
long and slender and usually truncate at the tip (rarely pointed in
Florida specimens).

The male bears seven tactile setae on tibia 1 and three tactile setae
on the proximal portion of tarsus 1, and the sensory setae vary in number
as in the female: from one to three such setae on tibia 1, and from one
to four such setae on the proximal part of tarsus 1.

333

Subfamily I etranychinae Herlese

The specimens on the type slide of yothersi are all females and
they represent two species, the other being that here identified as
Oligonychus coffeae. These two species are found commonly assoc¬
iated in South America. McGregor’s 1941 identification is accepted as
that of the first reviser.

Oligonychus major is here considered to be a synonym of Oligonychus
yothersi. The types are extremely deteriorated, but tarsus I of the
female bears four setae proximad of the duplex setae. The types of
major were from experimental avocado plots, and this is an important
host of yothersi. Ewing referred to the aedeagus as -being much larger
and differently shaped in comparison with ( americanus ) - ununguis.
The synonymy is probably correct.

Series studied by us in which males and females are associated
are from Richmond, Florida (F. G. Butcher), on avocado; Fredonia,

334

Spider Mites

Fig. 286. Oligonychus ■ punicae : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male; all coiti types.

335

Subfamily T etranychinae Herlese

Fig. 287. Oligonychus punicae: left, empodium I of male;
right, empodium I of female; coiti types.

Colombia (C. 11. Ballou), on coffee; Pomasqui, Ecuador (11. II. ^ ust),
on Capuli cherry; Guail labamba, Ecnutlor (11. R. Vast), on avocado;
and Concordia, Argentina (L. C. Knorr), on Salix alba.

Females alone from Florida are from Richmond (F. C. Butcher), on
avocado and mango; Sunland Groves (F. G. Butcher), on mango; Florida
City (F. G. Butcher), on avocado; Coral Gables (F. G. Butcher), on
mango; Perrine (F. G. Butcher), on mango, avocado, litchi, Euphora
longana, and Averrhoa carambola; Bomestead (D. 0. Wolfenbarger), on
mango and avocado; Orlando (L. C. Knorr), on camphor; and Gainesville
(L. C. Kuitert), on camphor.

Oligonychus punicae {Hirst), new combination
(Figures 286, 287, 288)

Paratetranychus punicae Hirst, 1926, Proc. Zool. Soc. Lond., 1926:
830. Types : males and females, Coimbatore, South India, on
pomegranate and grape; probably in the British Museum (Natural
History).

Paratetranychus coiti McGregor, 1941, Proc. Ent. Soc. Kash., 43 : 85;
McGregor, 1950, Amer. Midi. Nat., 44: 337. Types: males and
females, Chula Vista, California, on avocado; in the U. S. Nation¬
al Museum. New synonymy.

The female of Oligonychus punicae possesses seven tactile (and
one sensory) setae on tibia I and four tactile (and one sensory) setae
on tarsus I proximal to the duplex setae. This sex cannot be distin¬
guished from females of 0. yothersi, 0. mangiferus, and 0. peronis,
all of which also occur on broad-leaved tropical plants.

The aedeagus is distinctive among this group of species in that the
hook is rather broad and with the distal end abruptly narrowed to form
a fingerlike projection.

The synonymy of Oligonychus coiti with 0. punicae is based on
the study of type material.

336

Spider Mites

The only specimens, other titan the types, examined by us might
be considered topotypes of coiti in that they are from southern Cali¬
fornia (Walter Ebeling and Lee Jeppson) on avocado. Although formerly
a serious pest of avocado in this area in the past, this species has
seldom been encountered in recent years.

It is probable that this species is tropical Asian in origin, but it
may have been introduced to California from Central America.

01 igonychus peronis Pritchard and Baker, new species
(Figures 289, 290, 291)

The female of Oligonychus peronis belongs to that subgroup having
seven tactile setae on tibia I and four tactile setae on tarsus I proximal
to the duplex setae. The aedeagus shows that this species is closely
allied to 0. punicae, but the distal fingerlike end of the aedeagus is
extremely small and ventrally placed on the very bulbous enlargement.
This species is known only from Ecuador, on Derris sp.

Male. — Palpus with terminal sensillum no longer than fusiform
peg of last palpal segment. Peritreme straight distally, scarcely en¬
larged at tip. Tibia I with seven tactile and four sensory setae; tarsus

I with three tactile and three sensory
setae proximal to duplexes and with a
single tactile seta ventrally just beyond
duplexes. Tibia II with five tactile setae.
Empodial claw slightly longer than the
four pairs of proximoventral hairs. Dorsal
setae of body rather slender, tapering,
longer than longitudinal intervals be¬
tween them. Aedeagus forming a swollen
bulb caudally above the ventrally direct¬
ed, narrow and truncate distal end.
Length of body 266 p, including gnatho-
soma 320 p, greatest width of body 133 p.

Female. — Similar. Terminal sensil¬
lum of palpus considerably larger.
Stylophore broadly rounded medio-
anteriorly. Tibia I with seven tactile
and one sensory setae; tarsus I
with four tactile and one sensory setae
proximal to duplexes. Integumental
striae longitudinal immediately

F'ig. 288. Oligonychus punicae :
aedeagus; coiti type.

337

Subfamily 1 etranychinae lit-rlt'se

Fig. 289. Oligonychus peronis’ A.) tibia and tarsus I of female; R,1 tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

338

Spider Mites

Fig. 290. Oligonychus peronis: above, empodium I of male and terminal
segment of palpus; below, empodium I of female and terminal sensillum of
pal pus.

Fig. 291. Oligonychus peronis : aedeagus.

Subfamily l etrany chinae Herlese

Fig. 29 2. Oligonychus peruvianus : dorsal aspect of female.

anterior to genital flap. Length of body 333 g , including gnathosoma
400 g; greatest width of body 250 g.

Holotype. — Male, Santo Domingo, Pichincha, Ecuador, November
27, 1952 (H. R. ^ust), on Denis sp.; type no. 2144 in the U. S. National
Museum. Paratypes. — Two males, 19 females, Santo Domingo, Pichincha,
Ecuador, November 27, 1952 (11. R. ^ust), on Denis sp.

01 igorrychus primulae ( Oudemans ), new combination

Paratetranychus primulae Oudemans, 1931, Ent. Ber., 8(181): 291;
Geijskes, 1939, Meded. Landbouwh. Rageningen, 42(4): 35.
Types : eight females, Arnhem, Holland, on Primulus obconica;

340

Spider Mites

Fig. 293. Oligonychus p eruvianus: A.) tibia and tarsus I of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
II of mal e.

probably in the Rijksmuseum van Natuurlijke Historic, Leiden,
Holland.

The rotund body, the five pairs of proximoventral enipodial hairs,
the long dorsal setae and the dorsal striae of the body (Geijskes, 1939)
all indicate that Oligonychus primulae belongs to the Ununguis Group.
Males are unknown, and the status of this species must remain in doubt.

01 igonychus nuptialis ( Zacher ), new combination

Paratetranychus nuptialis Zacher, 1932, Zool. Anz., 97(7/8): 13. Types:
males and females, Einbeck, Germany, on “Myrthenstecklinge”;
probably in the Zacher collection.

Zacher’s description of nuptialis indicates, although by no means
certainly, that this species belongs to the Ununguis Group. The yellow¬
ish-red color of the body, as described by him, is found only in this
group, and his figure of the aedeagus indicates that it bends ventrad

341

Subfamily l etrany chinae fieriest •

ns in this group, lhe terminal enlargement of the aedeagus, as illus¬
trated by Zacher, will distinguish this species from all species of the
Ununguis Group.

Oligonychus kobachidzei (Reck), new combination

Parat etrany chus hobachidzei Heck, 1947, Soobsh. Akad. Nauk Gruz.
S.S.R., 8(7). De scribed from specimens from Georgia, S.S. H.,
on Platanus occidentalis.

We have not seen the description of this species.

01 igonychus mori (Yokoyama) , new combinat ion

P anonychus mori \ okoyama, 1929, Nippon Sangyo Gaichu Zensho
(Tokyo), p. 531. Described from male and female, Japan, on
mulberry.

Although \okoyama credited this species to kishida, no article by
kishida has been found in which the name was used. However, the
name is validated by Yokoyama, and his description clearly indicates
that this is a reddish species belonging to the Ununguis Group.

0 1 igonychus parva (Yokoyama), new combination

Tacebia parva Yokoyama, 1929, Nippon Sangyo Gaichu Zensho (Tokyo),
p. 536. Described from female, Japan, on mulberry.

\ okoyama validated this species, even though it was credited to
kishida. No reference to publication of tlje name by kishida has been
found. Parva was described as being very similar to mori, but smaller
in size.

Peruvianus Group

The Peruvianus Group is based on a single species that may be
readilv recognized by the shape of the dorsal setae of the body. These
setae are short, lanceolate, and nearly nude.

342

Spider Mites

Fig. 294. Oligonychus p eruvianus : tarsal appendages and aedeagus.

In common with the Ununguis Group the aedeagus bends ventrad and
tarsus I bears a single tactile seta ventral to the duplexes. In common
with the other groups, tibia I bears nine tactile setae and the empodium
bears only three pairs of proximoventral hairs. Tibia I bears one sensory
seta in the female, two sensory setae in the male. Tarsus I bears four
tactile setae proximal to the duplexes, plus one sensory seta in the
female and three sensory setae in the male. Tibia II possesses seven
(rarely six) tactile setae.

The integumentary striae of the female are distinctive in that they
are longitudinal between the third pair of dorsocentral hysterosomals.

Oligonychus peruv ianus (McGregor) , new combination

(Figures 292, 293, 294)

Tetranychus peruvianas McGregor, 1917, Proc. U. S. Natl. Mus.,
51(2167): 581, 589. Types : males and females, La Legua, Peru,
on willow; in the U. S. National Museum.

P aratetranychus peruvianus, McGregor, 1919, Proc. U. S. Natl. Mus.,
56(2303): 667; McGregor, 1950, Amer. Midi. Nat., 44(2): 346;
Baker and Pritchard, 1953, llilgardia, 22(7): 209.

P aratetranychus trinitatis Hirst, 1922, Proc. Zool. Soc. Lond., 1921:
801. Types: males and females, Trinidad, on grape; probably
in the British Museum (Natural History).

Oligonychus peruvianus has been recorded from Peru, Trinidad, and
southern California, on willow, grape, carob, and cotton. The colonies
are very restricted, being found on the undersides of the leaves.

343

Subfamily I etrany chinae Herlese

big. 29. «. Oligonychus stickneyi : A.) tibia and tarsus I of female; H.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

Pratensis Group

Mites tlmt belong to the Pratensis Group are distinguished by having
the proximoventral appendages of the male empodium I consisting of a
single pair of spurs (each with a trace of the first and second proximo-
ventral hairs).

The males are further recognizable in that the aedeagus bears a
strong bend dorsad, with the distal end either sigmoid or with a rather
compact distal enlargement.

Females are distinguishable as a group, but they cannot be differ¬
entiated as to species. Tibia I bears nine tactile setae. Tarsus 1 has
four tactile setae proximad of the duplex setae, and the venter of tarsus
I bears two tactile setae on the ventral surface (in the portion bearing
longitudinal striations) just distal to the location of the duplexes. The
dorsal striae of the females of the Pratensis Group are transverse
between the dorsocentral hvsterosomals, but they are longitudinal
between the sacrals. Dorsolateral striae of the body are mostly
transverse.

344

Spider Mites

The peritreme is straight distally, ending in a simple bulb. There
are three pairs of empodial hairs below the long and slender empodial
claw. The duplex setae on tarsus I are more widely spaced on the
dorsum of the segment than in other groups of Oligonychus except for
the illcGregori Group.

Mites belonging to the Pratensis Group feed characteristically on
grasses, and they are often pests of such crops as sorghum, maize,
sugar cane, and rice. Two species, ordinarily found on grasses, are
serious pests of the fruit of date palms.

Adult females are very small, pale yellowish or straw-colored, and
have dusky spots along each side.

Oligonychus stickneyi (McGregor), new combination

(Figures 295, 296, 297)

Paratetranychus stickneyi McGregor, 1919, Proc. Ent. Soc. Wash., 41:
253; McGregor, 1950, Amer. Midi. Nat., 44: 353. Types: males

345

Subfamily fetrany chinae Herlrse

and females, Whittier, California, on Bermuda grass; in the U. S.
National Museum.

ihe male of Oligonychus stichneyi may be recognized by having
the terminal enlargement of the aedeagus very large, about one-third
as long as the dorsal portion of the shaft, the anterior margin broadly
rounded, the caudal end acutely angulate, and with the axis of the
enlargement forming less than a 30 degree angle with the axis of the
shaft. The shaft is sharply constricted just before the dorsal bend.

Specimens other than the types that have been studied are from
Redlands, California (A. E. Pritchard), on Bermuda grass; Tulare
County, California, on corn; Santa Barbara, California (A. E. Pritchard),
on Bermuda grass; Riverside, California (Jack Hall), on Bermuda grass;
Indio, California, on corn; Avondale, Arizona (M. H. brost, Jr.), on
maize; and Jalostoc, Morelos, Mexico (J. J. Mckelvev), on maize.

346

Spider Mites

Fig. 298. Oligonychus grarrineus: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

Specimens from Windermere, Florida (0. D. Link), on maiden cane grass
appear to be identical.

McGregor recorded tlie following genera of grasses as hosts: Arundo,
Bouteloa, Cenchrus, Clitoris, Cynodon, Digitaria, Echinochloa, Eragr-
ostis, Setaria, Sorghum, and Sporobolus.

347

Subfamily I etrany chinae Herlese

I*ig. 299. Oligonychus grumineus : above, empodium I of
male; below, empodium I of female.

01 igonychus gramineus (McGregor), new combination

(Figures 298, 299, 300)

Paratetranychus gramineus McGregor, 1950, Amer. Midi. Nat., 44 : 339.
Types: males and females, Julian, California, on Hordeum
murinum ; in the U. S. National Museum.

Oligonychus gramineus is closely allied to 0. stickneyi , but the
distal enlargement of the aedeagus is narrower and the axis of the
enlargement forms a 45 degree angle with the axis of the shaft.

This species has been known only from the very southern coastal
area of California, from San Diego County to Los Angeles County. A
more northern collection, from Davis, California (F. M. Summers), on
rye, has been studied by us.

Oligonychus exs iccator ( Zehntner ), new combination
(Figure 301)

Tetranychus exsiccator Zehntner, 1897, Arch. Java-Suikerind., 5(1):
525; Zehntner, 1901, Arch. Java-Suikerind., 9(1): 193. Described
from specimens from Java, on sugar cane.

348

Spider Mites

Fig. 300. Oligony chus gramineus : aedeagus.

The figures of the aedeagus that were presented by Zehntner (1901)
indicate that this species belongs to the Pratensis Group and that it
is closely related to Oligony chus stickneyi. However, the caudal pro¬
jection of the aedeagal knob is rounded in Zehntner’s figures.

Swezey (1922) and Williams (1931) regarded this species as a sugar
cane pest in Hawaii, but their identification is in need of confirmation.
We have not seen this species.

Fig. 301. Oligony chus exsiccator : empodium and aedeagus (after Zentner).

349

Subfamily T etrany chinae Herlese

01 igonychus afrasiat icus (McGregor), new combination

(Figure 302)

Paratetranychus afrasiaticus McGregor, 1939, Proc. Ent. Soc. Rash.,
41(9): 255; McGregor, 1950, Anier. Midi. Nat., 44(2): 331. Types:
males and females, Biskra, Algeria, on dates; in the U. S.
National Museum.

Oligonychus Psirnplex, Hirst, 1920, Proc. Zool. Soc. Lond., 1920: 60;

Buxton, 1921, Bui. Ent. lies., 11: 299. Misidentification.
Paraletranychus simplex, Andre, 1932, Bui. Soc. Hist. Nat. Afr. Nord.,
23: 325. Misidentification.

The aedeagus of Oligonychus afrasiaticus has a moderately large
terminal knob, about one-fifth as long as the dorsal portion of the shaft.
The axis of the knob is parallel to that of the shaft; the anterior pro¬
jection is broadly rounded, and the posterior angulation is deflexed
at the tip, about as long as the anterior angulation. No sharp constriction
is evident on the shaft.

This species is reported to be a serious pest of dates in Algeria
and Iraq; and Buxton (1921) also recorded “khadhrawi” trees as a host.

01 igonychus pratensis {Banks), new combination

(Figures 303, 304, 305, 306)

Tetranychus pratensis Banks, 1912, Proc. Ent. Soc. Rash.., 14: 97;
Ewing, 1913, Ann. Ent. Soc. Amer., 6: 459; Types: females,
Pullman, Washington, on timothy; in the U. S. National Museum.
Paraletranychus pratensis, 3anks, 1915, U. S. Dept. Agr. Rep., 108:
37; McGregor, 1919, Proc. h. S. Natl. Mus. , 56(2303): 668;
McGregor, 1950, Amer. Midi. Nat., 44: 350.

Tetranychus simplex Banks, 1914, Pomona Jour. Ent. and Zool., 6: 57.

350

Spider Mites

Types: described from specimens from El Centro, California, on
date palm, in the Museum of Comparative Zoology, Cambridge,
Massachusetts. New synonymy.

Paratetranychus simplex, Banks, 1915, U. S. Dept. Agr. Rep., 108:
37;. McGregor, 1939, Proc. Ent. Soc. Wash., 41: 248; McGregor,
1950, Amer. Midi. Nat., 44: 352.

351

Subfamily I etrany china e tterlrse

Fig. 304. Oligonychus pratensis: A.) tibia and tarsus 1 of female; B.) tibia
ind tarsus II of female; C.) tibia and tarsus I of male; B.) tibia and tarsus II

>f male.

352

Spider Mites

P aratetranychus heteronychus Ewing, 1922, Proc. Ent. Soc. Wash.,
24: 105. Types : males and females, Coachella Valley, California,
on dates; in the U. S. National Museum. New synonymy.

The male of Oligonychus pratensis may be recognized by having
the distal knob of the aedeagus about twice as wide as the stem of
the knob, the axis of the knob forming a distinct angle with the axis

353

Subfamily I etranychinae Berlese

of the shaft. 'Hie dorsal margin of the knob may be nearly straight
with the tip slightly down, or it is curved or angulate. The anterior
projection of the knob is bluntly angulate, the posterior angulation
acute. No constriction of the shaft is evident.

Oligonychus pratensis has been inadequately characterized due
to the lack of males. An outbreak of this species on grasses and grains
occurred in the Pacific Northwest in 1951, and specimens collected
near Pullman, Washington, are regarded as topotypes. They represent
the same species previously known as the date mite in southern Cali¬
fornia.

1 his species is common on grasses in the western United States.
Specimens examined are from Pullman, Washington (H. S. Telford), on
wheat; Dishman, Washington, on grass; La Grande, Oregon (13. G.
Thompson), on wheat; La Grande, Oregon (R. W. Every), on grass;
Pickleville, Utah (G. S. Knowlton), on aspen; Indio, California (L. R.
Jeppson), on dates; and Riverside, California (Jack Hall), on Bermuda
grass.

Specimens from the eastern and midwestern United States differ
from specimens from the far West in that the knob of the aedeagus is
more slender, the anterior angulation more acute, and the caudal angula¬
tion somewhat more deflexed. Such collections have been studied from
Clovis, New Mexico (T. L. Harvey), on wheat; Garden City, Kansas
(C. F. Henderson), on wheat; Curtis and Benton, Louisiana (L. D.
Newsom), on Panicum sp.; Pelican Lake, T lorida (D. D. Questal), on
sugar cane; and Miami Beach, Florida (0. D. Link), on para grass.

In other males from Florida the aedeagal knob is somewhat smaller,
approaching that of Oligonychus indicus but with the dorsally bent
portion comparatively large in relation to the size of the shaft and
the anterior angulation evident. These collections are from Belle

354

Spider Mites

Fig. 307. Oligonychus modestus : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

Glade, Florida (R. Mathes), on sugar cane; Miami Beach, Florida (0. D.
Link), on smut grass; and Miami, Florida (0. D. Link), on broom grass.

01 igonychus indicus {Hirst), new combination

P aratetranychus indicus Hirst, 1923, Proc. Zool. Soc. Lond., 1923;
990; Rahman and Punjab, 1940, Proc. Ind. Acad. Sci. (ser B),
11: 189; Rahman and Sopra, 1940, Ind. Jour. Ent., 2: 201. Types :
males and females, India, on sorghum; probably in the British
Museum (Natural History).

P aratetranychus mexicanus McGregor and Ortega, 1953, Fol. Tec., 10: 3.
Types: males and females, Chapingo, Mexico, on maize and
Johnson grass; in the U. S. National Museum. New synonymy.

355

Subfamily I etranychinue Berlese

Fig. 308. Oligony cnus modestus:
aedeagus.

Oligonychus indicus is closely
allied to O. pratensis. Types of 0.
mexicanus (similar to the illustrated
types of indicus) are distinctive in
having the distal knob of the aedeagus
very small, directed caudo-dorsally ,
and with the anterior angulation virtually
absent. 1 he bend of the aedeagus forms
an ucute angle with the axis of the
shaft.

It is possible that the specimens
discussed in the last paragraph under
Oligonychus pratensis might be prop¬
erly referred to 0. indicus. The com¬
plex needs additional study.

01 igonychus modestus [Banks), new combination
(Figures 307, 308)

Tetranychus modestus Banks, 1900, U. S. Dept. Agr. Tech. Ser., 8: 73.
Types: males, Washington, D. C. on corn; in the U. S. National
Museum.

Paratetranychus modestus, Banks, 1915, Dept. Agr. Rep., 108: 37;
McGregor, 1919, Proc. L. S. Natl. Mas., 56(2303): 670; McGregor,
1950, Amer. Midi. Nat., 44: 344.

The aedeagus of Oligonychus modestus is distinctive in that the
distal end is scarcely enlarged, and the dorsal surface of the tiny
knob is curved and parallel to the axis of the shaft. The distal bend
is at a right or obtuse angle with the axis of the shaft.

In addition to the types from Washington, D. C. on com, specimens
have been examined from Washington, D. C. (F. A. McClure), on bamboo.

01 igonychus sacchari [McGregor), new combination

(Figures 309, 310, 311)

Paratetranychus sacchari McGregor, 1942, Jour. Univ. Puerto Rico,
26: 91; McGregor, 1950, Amer. Midi. Nat., 44: 351. Types: males
and females, Mavagiiez, Puerto Rico, on sugar cane; in the
U. S. National Museum.

356

Spider Mites

Fig. 309. Oligonychus sacchari: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

357

Subfamily l etranychinae Lierlese

Fig. 310. Oli gonychus sacchari: above, empodium I of
male; below, empodium I of female.

Th e male of Oligonychus sacchari is distinctive in having the distal
end of the aedeagus bent dorsad, tapering, strongly sigmoid, and with
the tip turned down.

This species was originally known from specimens collected on
sugar cane in western Puerto Rico, but McGregor later recorded speci¬
mens from the New Hebrides and Windward Islands, on dendrobium
orchids and foxtail millet.

01 igonychus oryzae (Hirst), new combination

P aratetranychus oryzae Hirst, 1926, Proc. Zool. Soc. Lond., 1926:
830. Types: males, Coimbatore, India, on paddy leaves; probably
in the British Museum (Natural History).

Oligonychus oryzae is closely related to 0. sacchari, but Hirst’s
drawing of the aedeagus shows the tip of the slender, sigmoid distal
end to be dorsally directed. The bent portion of the aedeagus is much
longer than in 0. iseilemae.

This species is known only from the types, from south India, on rice.

358

Spider Mites

01 igorrychus iseilemae [Hirst), new combination

Paratetranychus iseilemae Hirst, 1924, Ann. Mag. Nat. Hist. (ser. 9),
14: 524. Types: males and females, Coimbatore, South India,
on Iseilema laxum; probably in the British Museum (Natural
11 istory.

Oligonychus iseilemae is a grass infesting mite. Hirst’s figure
indicates that the aedeagus bears a small, sigmoid, dorsal bend without
any distal enlargement and with the tip directed upward. The peritreme
is distinctive among the group inasmuch as the distal end is described
as being U-shaped.

This species is known only from the types from South India.

Oligonychus stenoperitrematus ( Ugarov and N i kol ski i) , new
combination

Eurytetranychus stenoperitrematus Ugarov and Nikolskii, 1937, Sredneat.
Stant. Zasch. Iiastenii, p. 36. Described from males and females,
probably Tashkent, Russia, on corn, watermelon, cotton, and
th istle.

P aratetranychus stenoperitrematus, Baker and Pritchard, 1953, Hilgardia
22(7): 209.

Hie description of stenoperitrematus and its position in Ugarov
and Nikolskii’s key indicate that the empodium is a simple claw with
six ventral hairs. The peritreme is described as forming a simple,
enlarged ultimate compartment. The description of the aedeagus (not
illustrated) further indicates that this mite belongs to the Pratensis
Croup. No satisfactory identification of this spider mite can be made
at tli e present.

McGregori Group

The McGregori Group is closely allied to the Pratensis Group. Fe¬
males of the two groups bear similar patterns of dorsal striae on the
idiosoma, the striae behind the inner sacrals being longitudinal and
the dorsolateral striae being mostly transverse. Tibia 1 bears nine

359

Subfamily I etranychinae Herlese

Fig. 311. Oligonychus sacchari :
aedeagus.

tactile (and one sensory) setae; and
tarsus 1 bears four tactile (and
one sensory) setae proximal to t lie
duplexes, and two tactile setae
just distal to the duplexes on the
ventral side. There are similarly
only three pairs of proximoventral
empodial hairs. However, the peri-
tremes are strongly retrorse distally,
and the duplex setae on tarsus 1
are more widely spaced. More¬
over, members of the McCregori
Group are not known to occur on
grasses.

The aedeagi of the species re¬
ferred to the McCregori Group are
distinctive in that the distal end
is bent dorsad and with a very long
appendages of empodium 1

and slender termination. The proximoventral
of the male consist of three pairs of hairs.

01 igonychus mcgregori ( Baker and Pritchard), new combination
(Figures 312, 313, 314)

P aratetranychus mcgregori Baker and Pritchard, 1953, llilgardia, 22(7):
209. Holotype: male, Chinandega, Nicaragua, on cotton; in the
U. S. National Museum.

The female of Oligonychus mcgregori may be recognized by the group
characters. The very slender prolongation of the aedeagus is distinctive.

This species is known only from the types from Central America,
on cotton.

Oligonychus gossypii (Zacher), new combination
(Figure 315)

P aratetranychus- gossypii Zacher, 1920, Zts. angew\ h,nt., 7: 183;
Hirst, 1926, Proc. Zool. Soc. Lond., 1926: 832; Andre, 1933,

360

Spider Mites

Fig. 312. Oligonychus mcgregori: dorsal aspect of female.

Bui. Mus. Hist. Nat. Paris (ser. 2), 5: 306. Types: males and
females, Togo, Africa; probably in the Zacher collection.

Descriptions of Oligonychus gossypii will not definitely determine
whether this species is referable to the Mcgregori Group. However,
published figures of the aedeagus indicate that this species is either
closely allied to 0. mcgregori, or else it is worthy of a group of its
own.

Hirst recorded this species from Sierra Leone, Africa, on cassava
and beans; and from Portuguese West Africa, on papaya. It was originally
described from cotton.

361

Subfamily Tetranychinae fieriest*

Fia. 313. Oligonychus mcgregori: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

362

Spider Mites

Fig. 314. Oligonychus mcgregori: A.) aedeagus;
B.) empodium II of female.

Fig. 315. Oligonychus gossypii : aedeagus.

Pritchardi Group

Tlie Pritchardi Group of the genus Oligonychus is readily recog¬
nizable by the integumentary pattern of the striae on the dorsum of
the female, the striae being transverse between the inner and outer
sacrals, together wdth the tibial chaetotaxy. The female bears nine
tactile (and one sensory) setae on tibia 1; four tactile (and one sensory)
setae on tarsus I proximal to the duplexes; and two tactile setae disto-
ventrad of the duplexes on tarsus I. There are only three pairs
of proximoventra! hairs on the empodium.

I ll e male bears three pairs of short, proximoventral hairs on empodium

363

Subfamily Tetranychinae Herlrsr

Fig. 316. Oli gonychus biharensis : above, tibia and tarsus I
of female; below, tibia and tarsus 1 of male.

1 in contradistinction to the Pratensis Group. The form of the aedeagus
is distinctive in that there is a short and broad curvature upward with
a long distal knob; the distal end of the knob is drawn out and may be
ventrally directed to give the aedeagus the appearance of a primary
ventral bend.

Members of the Pritchardi Group are usually found on trees. They
are very small mites, yellowish, and with parallel-sided bodies.

364

Spider Mites

Oligonychus biharensis [Hirst), new combination

(Figures 316, 317, 318)

P aratetrany chus biharensis Hirst, 1925, Proc. Zool. Soc. Lond., 1925:
69. Types : males and females, Pusa, India, on rose; probably
in the British Museum (Natural History).

P aratetrany chus hawaiiensis McGregor, 1950, Amer. Midi. Nat., 44:
340. Types: males and females, Honolulu, Hawaii, on loquat;
in the U. S. National Museum. New synonymy.

The figures of the aedeagi presented by Hirst and McGregor, together
with a study of specimens having similar aedeagi, convince us that
hawaiiensis is a synonym of biharensis.

Females are readily differentiated from other members of the group
by having the peritremes retrorse distally.

Oligonychus pritchardi (McGregor), new combination
(Figures 319, 320, 321)

P arat.etranychus pritchardi McGregor, 1950, Amer. Midi. Nat., 44: 350.
Type s : males and females, Berkeley, California, on vallev oak;
in the U. S. National Museum.

366

Spider Mites

Fig. 320. Oligonychus pritchardi: empodium I of male.

Fig. 321. Oligonychus pritchardi :
aedeagus.

the University of California
Berkeley, California (A. E.
Washington (E. J. Newcomer),
on oak; Oregon City, Oregon
Oregon (E. W. Baker), on oak.

The male of Oligonychus pritchardi
is distinctive in that the distal hook
is nearly straight on the dorsal margin,
except for the obtuse angulation. The
tip of the aedeagus reaches a level of
the axis of the shaft. The peritreme
has a simple bulb distally.

The female is indistinguishable from
Oligonychus propetes.

This species forms compact col¬
onies that live under very dense
canopies of webbing, either on the
upper or lower sides of leaves of
deciduous oaks. In this biological
characteristic it differs considerably
from that of other species of Oligo¬
nychus.

Oligonychus pritchardi was de¬
scribed from specimens from oak on
campus. We have studied specimens from
Pritchard), on valley oak; Wiley City,
on oak; Yakima, Washington (E. W. Baker),
(E. W. Baker), on oak; and Hood River,

Oligonychus propetes Pritchard and Baker, new species

(Figures 322, 323, 324)

The female of Oligonychus propetes resembles that of 0. pritchardi .
It differs from O. biharensis in that the peritreme is straight distally,

367

Sub farm' ly / etrany chinae Berlese

Fig. 322. OligonyctiUS propetes ■ A.) tibia anH tarsus I of female; R.) tibia
and tarsus I of male; C.) tibia and tarsus II of male.

368

Spider Mites

Fig. 324. Oligonychus
propetes : aedeagus.

and from 0. hadrus in that the mem¬
bers of each duplex are very unequal.
The aedeagal barb is strongly convex
on the dorsal margin with the acuminate
tip directed ventrally, much as ir
Oligonychus hadrus.

This mite is apparently common
on deciduous oaks in the eastern
United States.

Male. — Palpus with terminal sen-
sillum rudimentary. Peritreme straight
distally, ending in a simple bulb.
Tibia I with nine tactile and four
sensory setae; tarsus I with four
tactile and two (or three) sensory

Fig, 325. Oligonychus hadrus : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; B.) tibia and tarsus II
of male.

369

Subfamily I etranychinae Berlese

<

Hg. 326. Oligony chus hadrus : empodium I of female.

setae proximal to duplexes, with a pair of tactile setae ventrally at
level of duplexes; duplexes each with proximal member very short;
empodium 1 a hooked claw, longer than the three pairs of proximoventral
hairs. Tibia II with five tactile setae. Dorsum of body with setae slender
and tapering, longer than intervals between bases. Aedeagus curved
dorsad but terminal enlargement large, with short proximodorsal angula¬
tion and with long caudoventrally curved terminal angulation. Length
of body 266 p, including rostrum 340 p; greatest width of body 166 p.

Female. — Similar. Palpus with terminal sensillum large, three times
as long as wide at base. Stylophore broadly convex cephalically. Tibia

1 with nine tactile and one sensory setae; tarsus 1 with four tactile
and one sensory setae proximal to duplexes. Length of body 345 p,
including gnathosoma 440 p; greatest width of body 200 p.

Holotype. — Male, Tyson’s Corner, Virginia, July 24, 1951 (E. ft.
Baker), on oak; type no. 2145 in the U. S. National Museum. Para-
types. — Nineteen males, 35 females, Tyson’s Corner, Virginia, July 11
and 24, 1951 (E. Vi. Baker), on oak; 8 males, 8 females, McLean, Vir¬
ginia, August 18 and September 4, 1952 (E. ft. Baker), on oak; 15 males,
35 females, ftashington, D. C., July 4, 1953 (E. ft. Baker), on oak;

2 males, 1 female, Durham, North Carolina, June 19, 1953 (A. E.
Pritchard), on white oak.

01 igonychus hadrus Pritchard and Baker, new species

(Figures 325, 326, 327)

Adults of Oligonychus hadrus closely resemble those of 0. pritchardi
and 0. propetes, but both sets of duplex setae on tarsus II are composed

370

Spider Mites

Fig. 327. Olig onychus hadrus : aedeagus.

of members that are more or less similar in length, rather than having
the proximal member of each duplex very short. Moreover, the distal
sensory rod on the female palpus of Oligonychus hadrus females is
very slender, over four times as long as wide.

The aedeagus of Oligonychus hadrus closely resembles that of
0. propetes. The distal enlargement is strongly convex on the dorsal
margin, and the acuminate tip is caudoventrally directed and reaching
the level of the axis of the shaft.

Male. — Palpus with terminal sensillum rudimentary. Peritreme straight
distally, ending in a simple bulb. Tibia 1 with nine tactile and four
sensory setae; tarsus I with four tactile and three sensory setae proximal
to duplexes; with a pair of tactile setae ventral to duplexes; duplexes
each with the proximal member about two thirds as long as distal mem¬
ber; empodium I cultriform, longer than the three pairs of proximoventral
hairs. Tibia II with six (or seven) tactile setae. Body with dorsal
setae slender, tapering, longer than longitudinal intervals between
them. Aedeagus with ventral surface curved dorsad, but the distal
enlargement large, with a small anterior angulation and with a large,
caudoventrally curved projection. Length of body 266 p, including rostrum
320 p.

371

Subfamily I etrany chinae Herlese

pacif icus

Fig. 328. Tetranychus, aedeagi of Pacificus Group.

F emale. — Similar. Palpus with terminal sensillum slender, somewhat
over four times as long as wide. Stylophore convex anteriorly. 1 ibia 1
with nine tactile and one sensory setae: tarsus I with four tactile and
one sensor)' setae proximal to duplexes. Length of body 266 p, including
gnathosoma 340g; greatest width of body 153.p.

Holotype. — Male, Pretoria, Transvaal, South Africa, March 21, 1951
(H. k. Munro), on Combretum zeyheri; type no. 2146 in the U. S. National
Museum. Paratypes. — One male, 7 females, Pretoria, Transvaal, South
Africa, January 2, 1951 (E. k. Hartwig), on Combretum zeyheri-, 1 male,
20 females, Pretoria, Transvaal, March 21. 1^51 (II. k. Munro), on
Combretum zeyheri.

372

Spider Mites

desertorum mexicanus

/

tumidellus

Fig. 329. Tetranychus, aedeagi of Desertorum and Tumidus Groups.

01 igonyclws brev ipodus ( Targioni Tozzetti)

Heteronychus ? brevipodus Targioni Tozzetti, 1878, Ann. Agric., 1: 255.
Described from specimens from (probably Florence) Italy, on
holly oak.

Oligonychus brevipodus, Berlese, 1886, Acari Dann. Piante Coltiv.,
p. 24; Canestrini, 1889, Atti Reale 1st. Veneto Sci. Let. Arti
(ser. 6), 7: 534; Hirst, 1920, Proc. Zool. Soc. Lond., 1920: 60.
Oligonychus quercinus. Hirst, 1920, Proc. Zool. Soc. London, 1920:
59. Misidentification.

373

Subfamily I etrany chinae Rerlest

Oligonychus minimus, Geijskes, 1939, Meded. Landbouwh. Wageningen,
42(4): 30. Misidentification.

Targioni Tozzetti originally emphasized that the empodium of brevi-
podus is clawlike, his description being based on a nymph. Berlese
similarly appears to have figured a nymph as his identification of this
species, but he does indicate, although inaccurately, that proximoventral
hairs are present.

Examination of Hirst’s quercinus from oaks in England shows that it
is structurally related to 0. coffeae, although the small size and pale
color belong to the Pritchardi Group. However, we consider quercinus
to be a synonym of Eotetranychus aurantii.

Hirst also pointed out the possibility that Oligonychus brevipodus
Berlese, as well as T etranychus virescens Berlese (apparently a manu¬
script name) might represent the same species.

The specific status of Oligonychus brevipodus must be based on
topotype material.

GENUS TETRANYCHUS DUFOUR

T etranychus Dufour, 1832, Ann. Sci. Nat. Paris, 25: 276; Koch, 1836,
Deutsche Crust. Myr. Arach., fasc. 1, 10; Duges, 1834, Ann.
Sci. Nat. Paris (ser. 2), 1: 14; Koch, 1842, Uebers. Arach. Syst.,
3: 58; Donnadieu, 1875, Ann. Soc. Linn. Lyon (n. ser.), 22: 147;
Murray, 1877, Econ. Ent. Apt. p. 97; Canestrini and Fanzago,
1878, A tti reale Istit. Ven. Sci. Let. Arti (ser. 5), 4: 148;
Canestrini, 1889, Atti Reale Istit. Ven. Sci. Let. Arti (ser. 6),
7: 494; Banks, 1900, U. S. Dept. Agr. Div. Ent. Tech. Ser.,
8: 70; Banks, 1907, Proc. U. S. Natl. Mus., 32(1553): 598;
Trag&rdh, 1915, Zts. ang. Ent., 2: 163; Irag&rdh, 1915, Meded.
Centralanst. Forsoks. Jordbruks. Ent. Avd., 20: 19; McGregor,
1919, Proc. U. S. Natl. Mus., 56(2303): 649; Hirst, 1920, Proc.
Zool. Soc. Lond., 1920: 49; Vitzthum, 1929, Tierw. Mitteleur.,
3(7): 49; Oudemans, 1930, Ent. Ber. 8(175): 158; Oudemans,
1931, Ent. Ber., 8(177): 190: Oudemans, 1931, Ent. Ber., 8(178):
221; Oudemans, 1937, Krit. Hist. Overz. Acer., 3(C): 1012;
Geijskes, 1939, Meded. Landbouwh. K ageningen, 42(4): 35;
Garman, 1940, Bui. Conn. Agr. Exp. Sta., 431: 80; ttomersley,
1940, Trans. Roy. Soc. S, Australia, 64: 256; McGregor, 1950,
Amer. Midi. Nat., 44(2): 277; Baker and Pritchard, 1953, Hil-
gardia, 22(7): 212.

374

Spider Mites

cucurbitae

marianae

piercei

Fig. 330, T etranychus, aedeagi of Telarius Group.

Distigmatus Donnadieu, 1876, Ann. Soc. L.inn. Lyon (1875), 22: 146.
Type of genus: (Distigmatus pilosus Donnadieu) T etranychus
telarius (Linnaeus); monobasic.

T etranychus ( Epitetranychus ) Zacher, 1916, Mitt. kais. biol. Anst.
Land-Forstvv., 16: 22. Type of subgenus: (T etranychus altheae
Hanstein) = T . telarius (Linnaeus); by original designation.
Epitetranychus, Zacher, 1916, Mitt. kais. biol. Anst. Land-Forstw., 16:

24; Oudemans, 1931, Ent. Her., 8(177): 193.

Septanychus McGregor, 1919, Proc. U. S. Natl. Mus., 56(2303):663; Mc¬
Gregor, 1950, Amer. Midi. Nat., 44(2) :3 16. Type of genus: Tetrany-
chus tumidus Hanks, by subsequent designation of Baker and
Pritchard (1953).

Amphitctranychus Oudemans, 1931, Ent. Her., 8(178): 225; Geijskes,
193^, Meded. Landbouwh. Wageningen, 42(4): 32. Type of genus:
Telranychus viennens is Zacher; by original designation and
monobasic. New synonymy.

375

Subfamily I etranychinae Berlese

Mites belonging to the genus T etranychus feel on the underside of
leuves of most of the ungiospermous plants, usually forming colonies,
at least to start with, and sometimes producing a great deal of webbing.
1 he eggs are pearly, spherical, and without a dorsal stipe.

Adult females in the more northern climates are nearly always green¬
ish or straw-colored, but those in the tropical areas are carmine in basic
color. 1 hey overwinter, or enter a non-feeding phase, as orange females;
elsewise reproduction is continuous throughout the year.

I he genus Tetranychus may be recognized by having only one pair
of para-anal setae (the postanals being absent) and by having the em-
podium composed of three (only two in T. fijiensis) pairs of
proximoventral hairs on the female, or on tarsi III and IV of the male,
above which there is a rudimentary or small spur, much shorter than
the ventrally directed hairs, lhe paired empodial hairs are all similar
in length and width (except in /. fijiensis).

I he end of the peritreme always bears a long, four or five chambered
hook, rarely anastomosing. The duplex setae on tarsus 1 are widely
separated on the dorsum on the tarsus, and this segment is long and
gradually narrows distally. Empodium 1 of the male usually consists
of a pair of short, tridigitate appendages with or without a mediodorsal
spur, ami tarsus II usually bears a short spur above the paired empodial
empodial hairs, lhe aedeagus bends sharply dorsad, and the develop¬
ment of the distal end is characteristic of the species. Dorsal setae
of the body are long and slender, and they are not borne on tubercles.

Species Erroneously Referred to the Genus Tetranychus

Less than a century ago, some scientists believed that red-spider
mites were the adult forms of chiggers or eriophyid mites. Related
families of predaceous, prostigmatic mites were still not clearly dif¬
ferentiated. It is not surprising, therefore, that a few species have
been described in or transferred to the genus Tetranychus although
they properly belong to other families. Hie following list comprises
such names known to us:

prunicolor Duges, 1834
caudatus Duges, 1834
trombidinus Duges, 1834
major Duges, 1834
longipes Duges, 1834
celer Duges, 1834
glabrum Duges, 1834
salicis Koch, 1838

Raphignathidae

Phvtoptipalpidae

St igmaeidae

Lupodidae

Eupodidae

Tydeidae

Stigmaeidae

Tvdeidae

376

Spider Mites

tini Boisduval, 1867
taxi Murray, 1875
molestissimus (\\ eyenberg), 1876
tlalsahuate (Murray), 1877
superba (Canestrini), 1888
longirostris Mola, 1907
vestitus Canestrini and Fanzago, 1876
For a complete list of tbe tetranychids that have been referred to
the genus Tetranychus, see the index.

The following names appear to be nomina nuda : Tetranychus gibbus
Koch; and T. brevipes Koch. The original description of one other
species has not been located. This is Tetranychus ulicis Jourdain,
referred to by Andre (1933) and considered by him to be a synonym of
the mite that we refer to as Tetranychus telarius.

Phytoptipalpidae
Eriophyidae
Trombiculidae
Trombiculid ae
Raphignathidae

Aphidae

Stigmaeidae

1.

1.

2.(1).

2.(1).

3.(2).

3. (2).

4. (3).

4. (3).

5. (4).

5. (4).

6. (3).

Key to species of TETRANYCHUS

Empodium with two pairs of empodial hairs, the dorsal pair
shorter than the ventral pair; mediodorsal spur of empodium
nearly one-half as long as proximoventral hairs (Fijiensis

Group) . fijiensis (p. 382)

Empodium with three pairs of empodial hairs, all similar in
length; mediodorsal spur of empodium not over one-third as
long as proximoventral hairs . 2

Peritreme with distal end irregularly anastomosing (\ iennensis

Group) . viennensis (p. 384)

Peritreme with distal end forming a simple hook. ... 3

Tarsus I with proximal pair of duplex setae in line with most

other proximal setae (Desertorum Group) . 4

Tarsus I with proximal pair of duplex setae distad of other
proximal tactile setae . 6

Knob of aedeagus nearly one-third as long as dorsal margin

of shaft . g/'gas (p. 405)

Knob of aedeagus not over one-fourth as long as dorsal margin
of shaft . 5

Aedeagus with knob about one-fourth as long as dorsal margin

of shaft . desertorum (p. 403)

Aedeagus with knob scarcely larger than stem and the caudal
angulation absent . ludeni (p. 405)

Empodium with an obvious empodial spur (Tumidus Group) . 7

377

Subfamily Tetranychinae fieriest-

6. (3).

7. (6).

7. (6).

8. (7).

8. (7).

9. (8).

9. (8).

10. (9).

10. (9).

11. (9).

11. (9).

12. (6).

12.(6).

13.(12).

13.(12).

Kmpodiuin (except for legs 1 and 11 of male) with the empodial
spur very tiny or absent . 12

Fmpodial spur at least one-third as long as proximoventral

hairs . 8

Fmpodial spur not over one-fourth as long as proximoventral
irs . 11

Knob of aedeagus with anterior projection broadly rounded

. turnidus (p. 408)

Knob of aedeagus with anterior projection ungulate ... 9

Aedeagus with knob less than twice as wide as its stem, the

angulations similar . tumidellus (p. 409)

Aedeagus with knob four times as wide as its stem, the caudal
angulation much longer than the anterior angulation ... 10

Axis of aedeagal knob parallel to axis of shaft ....

. mexicanus (p. 411)

Axis of aedeagal knob forming an angle with axis of shaft
. magnoliae (p. 412)

Palpus of male with terminal sensillum three times as long

as broad at base; knob of aedeagus with posterior angulation
but slightly longer than anterior angulation . cocosi (p. 414)
Palpus of male with terminal sensillum over four times as long
as broad at base; knob of aedeagus with posterior angulation
twice as long as anterior angulation . . cocosinus (p. 417)

Female* with transverse (sometimes irregularly so) striae
between the third pair of dorsocentral hysterosomals and in the
area caudad of these setae (Pacificus Group) .... 13

Female with longitudinal striae between the third pair of dorso¬
central hysterosomals and with a diamond shaped pattern in
the area caudad of these setae (Telarius Group) .... 19

Female with transverse integumentary striae between inner

sacral setae . 14

Female with longitudinal or irregular integumentary striae
between inner sacral setae . 15

* Males belonging to the Pacificus and Telarius Groups may be identified by
reference to figures of the aedeagus, but it is exceedingly difficult to present
a key to the shapes of the simple aedeagi without considering the integumentary
striae of the females. Moreover, females are found more easily than the males
and are nearly always present in any collection.

378

Spider Mites

14.(13).

14. (13).

15. (13).

15. (13).

16. (15).

16. (15).

17. (16).

17. (16).

18. (15).

18. (15).

19. (12).

19. (12).

20. (19).

20. (19).

21. (20).
21.(20).

22.(21).

Aedeagus with bent portion sigmoid, with or without a small
anterior angulation, the distal end being at a level of caudal
end of bend ......... mcdanieli (p. 386)

Aedeagus with a long posterior angulation on distal knob, its
tip reaching well beyond level of caudal end of bend
. . , pacificus (p. 388)

Empodia I and II of male each with an obvious mediodorsal

spur . 16

Empodia I and II of male each with mediodorsal spur rudimen¬
tary or absent . 18

Posterior angulation of aedeagal knob over three times as
long as anterior angulation ...... homorus (p. 390)

Posterior angulation of aedeagal knob not over twice as long
as anterior angulation . 17

Aedeagus with distal knob strongly enlarged, about one-half

as long as dorsal margin of shaft .... schoenei (p. 392)
Aedeagus with distal knob smaller, about one-fourth as long as
dorsal margin of shaft . canadensis (p. 393)

Knob of aedeagus over twice as wide as its stem, the anterior
angulation acute and the posterior angulation slender

. Iambi (p. 399)

Knob of aedeagus less than twice as wide as its stem, the
anterior angulation obtuse and the posterior angulation very
short . polys (p. 396)

Knob of aedeagus berry-like, the rounded anterior projection
more strongly developed than the posterior convexity

. . . . cucurbitae (p. 419)

Knob of aedeagus not globular, the caudal projection angulate
. .20

Aedeagal knob comparatively large, about one-third or one-

fourth as wdde as the dorsal margin of the shaft .... 21

Aedeagal knob very small, not over one-sixth as long as dorsal
margin of shaft . 23

Knob of aedeagus with dorsal margin obtusely angulate; female

greenish . atlanticus (p. 424)

Knob of aedeagus with dorsal margin broadly convex; female
carmine . 22

Anterior projection of aedeagal knob much broader than base
of posterior angulation . merganser (p. 429)

379

Subfamily T etrany chinae Herlese

22. (21). \nterior projection of aedeagal knob similar in width to base

of posterior angulation . hydrangeae (p. 425)

23. (20). Axis of knob of aedeagus forming a strong angle with axis of

shaft, the posterior angulation obviously longer than the tiny
anterior angulation . 24

23. (20). Axis of knob of aedeagus parallel or forming a small angle

with axis of shaft, the posterior angulation no longer than
anterior angulation . telarius (p. 432)

24. (23). Knob of aedeagus wider than base of its stem ....

. marianae (p. 429)

24.(23). Knob of aedeagus much smaller than base of its stem

. piercei (p. 431)

380

Spider Mites

Fig. 332. Tetranychus fijiensis'. above, tibia and tarsus I of
male; below, tibia and tarsus II of male.

Fijiensis Group

The empodium of the single species on which the Fijiensis Group
is based departs strongly from others in the tribe Tetranycliini in that
there are only two pairs of proximoventral hairs, and the dorsal pair
is considerably smaller than the ventral pair. The mediodorsal spur of
the empodium is strong, about one-half as long as the longer pair of
proximal hairs. Such tarsal appendages suggest that this species is
derived from a form similar to Allonychus braziliensis.

There is a single pair of para-anal setae. Tarsus 1 is attenuated
and with the duplex setae widely spaced. The peritreme is strongly
U-shaped distally. The integumentary striae on the hysterosoma between

381

Subfamily Tetranychinae Herlese

Fig. 333. Tetranychus fijiensis : A.) terminal segment of palpus of male;
R.) terminal sensillum of palpus of female; C.) empodium I of female; D.)
empodiuin I of male.

the third pair of dorsocentrals and the inner sacrals form a diamond¬
shaped pattern.

Empodium I of the male is similar to the others, except that the
proximoventral hairs are nearly equal in length. The aedeagus also
departs strongly from other members of the genus Tetranychus in that
it is very slender and tapering, curved dorsad.

The group may be worthy of subgeneric or generic standing.

382

Spider Mites

Tetranychus fijiensis Hirst
(Figures 331, 332, 333, 334)

Tetranychus fijiensis Hirst, 1924, Ann. Mag. Nat. Hist. (ser. 9), 14:
523. Types : male and female, Ovalau, Fiji, on coconut; probably
in the British Museum (Natural History).

Specimens examined by us are from Fiji (H. W. Simrnonds), on coco¬
nut; Nakuoro Island, Micronesia (Townes), on Cyrtosperma chamissonis ;
and Likiep Island, Micronesia (Oakley), on coconut.

Viennensis Group

The irregularly anastomosing termination of the peritreme is char¬
acteristic of this group. The proximal pair of duplex setae on tarsus I
is distal to the other proximal setae; and the empodial spur is rudi¬
mentary or absent.

The actively feeding female is described as being greenish-yellow
in color (l)osse, 1953). Integumentary striae of the female are transverse
between the third pair of dorsocentral hysterosomals and also the inner
sacrals. The distal portion of the aedeagus is very long and slender.

383

Subfamily 1 etrany chinae II e rl e s e

335. Tetranychus vi ennensis: above, tibia and tarsus I of
female; below, tibia and tarsus II of female.

384

Spider Mites

Fig. 336. Tetranychus viennensis : terminal segment of
palpus of female and peritreme.

Tetranychus viennens is Zacher

(F’igures 335, 336)

Tetranychus ( Epitetranychus ) viennensis Zacher, May 1920, Vorl. Diag.
neuer Spinnmilb., p. 1; Zacher, 1921, Zts. ang. Ent., 7: 186.
Types: male and female, Wien, Austria, and Berlin-Dahlem,
Germany, on apple, pear, sour cherry, and sweet cherry; possibly
in the Zacher collection.

Tetranychus viennensis, Reck, 1950, Trudy Inst. Zool. Akad. Nauk.
Gruz. S.S.R., 9: 127.

Amphitetrany chus viennensis, Oudemans, 1931, Ent. Ber., 8(178): 225;

Geijskes, 1929, Meded. Landbouwh. Viageningen, 42(4): 32.
Tetranychus crataegi Hirst, 1920, Proc. Zool. Soc. Lond., July 1920:
p. 51; Hirst, 1923, Proc. Zool. Soc. Lond., 1923: 991. Types:
male and female, Salisbury, Wilts, England, on hawthorn; probably
in the British Museum (Natural History).

Apotetranychus longipenis Ugarov and Nikolskii, 1937, Trudy Sreadneaz.
Stan. Zasch. Hast., p. 34. Described from male and female speci¬
mens, Tashkent, Russia, on apple. A 'em synonymy.

According to the recommendations of the International Commission
on Zoological Nomenclature (Bui. Zool. Nom., 4: 217; 1950), the pri¬
vately published (mimeographed) paper by Zacher (1920) constitutes
publication. Tetranychus viennensis, therefore, has priority over T.
crataegi.

The aedeagus of T etranychus viennensis is bent sharply dorsad, and
the distal knob is modified as a small anterior angulation near the base
of the bent portion, with the caudal angulation very attenuated and
tapering.

385

Subfamily Tetranychinae Rerlese

ltiis species lias been recorded from England, on hawthorn; from
Germany and Austria on apple, pear, and both sweet and sour cherry;
and from Georgia, S.S.R., on apple, pear, prune, cherry, blackthorn,
and oak. We have studied a series of females transmitted by courtesy
of E. Zacher.

Tetranychus virginis [Ugarov) , new comb i nat i on

Apotetranychus virginis Ugarov, probably 1937, Vuipisha iz otcheta
za 1936g, No. 465: 1-4. ( reference in Zool. Record); 1937, Inst.
Zaslich. rast. za 1936g, 11 (reference in Reck, 1952a).

1 he article in which this species was described has not been seen,
lhe generic transfer here is based on Ugarov’s conception of the genus
Apotetranychus in the paper in which “ Apotetranychus ” longipenis
was described.

Pacificus Group

lhe Pacifi cus Group is defined principally on the basis of females.
In this sex the integumentary striae are transverse (sometimes irregu¬
larly so) between the third pair of dorsocentral hysterosomals , and
they are also transverse in the area between these setae and the inner
sacrals. The area between the inner sacrals may bear either transverse
or longitudinal striae.

The distal end of the peritreme consists of a simple hook. The
proximal pair of duplex setae on tarsus I is distad of the other proximal
setae? and the empodial spur is rudimentary or absent. The distal end
of the aedeagus varies from being sigmoid to having a very large knob.

In life the actively feeding adult females are greenish, with a pair
of dark medially and a pair of dark spots caudally. Species in this
group are found in temperate zones.

386

Spider Mites

Fig. 338. Tetranychus pacificus : dorsal aspect of female.

Tetranychus mcdanieli McGregor

(Figure 337)

Tetranychus mcdanieli McGregor, 1931, Proc. Ent. Soc. Wash., 33:
193; McGregor, 1950, Amer. Midi. Nat., 44(2): 292; Pritchard and
Baker, 1952, Hilgardia, 21(9): 266. Types : males and females,
Bridgman, Michigan, on raspberry; in the U. S. National Museum.

387

Subfamily l etranychinae Berlese

Fig. 339. Tetranychus pad ficus: female
showing body markings when feeding.

388

Spider Mites

Fig. 340. T etranychus pacificus: aedeagi.

Tetranychus mcdanieli may be recognized by having the dorsally
directed bend of the aedeagus sigmoid, the distal end being directed
dorsocaudad at about a 45° angle and terminating at a level of the
posterior margin of the bend. The bent portion may narrow gradually
or there is often a small, obtuse, anterior angulation.

The female resembles that of Tetranychus pacificus in that the
integumentary striae are transverse between the third pair of dorso-
central hysterosomals and also between the inner sacrals.

For many years this species was known only from the type series
from Michigan. However, it is now known to be a serious pest of decidu¬
ous fruit trees in the northwestern United States. Collections have been
studied from British Columbia, Washington, Utah, California, Montana,
North Dakota, Michigan, and New \ork; on apple, plum, prune, and
raspberry.

Tetranychus pacificus McGregor

(Figures 338, 339, 340)

Tetranychus pacificus McGregor, 1919, Proc. U. S. Natl. Mus., 96(2303):
657; lleriot, 1941, Canad. Ent., 73(1): 1; McGregor, 1950, Amer.
Midi. Nat., 44(2): 296; Pritchard and Baker, 1952, llilgardia,
21(9): 265; Baker and Pritchard, 1953, llilgardia, 22(7): 215.
Types: males and females, Portland, Oregon, on Philadelphicus
gordonianus, Viciia sp., and Kibes sp., and Tracy, California,
on chinaberry; in the U. S. National Museum.

T etranychus pacificus may be recognized by having the integumentary
striae transverse between both the third pair of dorsocentral hystero¬
somals and the inner sacrals of the female (as in 7'. mcdanieli), together
with having the knob of the aedeagus directed slightly dorsad and with
the terminal angulation ending well beyond the level of the bend.

This species is an important pest of agriculture in the far western
United States. It is known to occur in Idaho, Oregon, and California.

Subfamily Tetranychinae lit-rlese

Fig. 341. Yetrany cuus hornoms : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

390

Spider Mites

Fig. 342. Tetranychus homorus : aedeagus.

Crops that are subject to severe infestation include cotton, deciduous
fruit trees and walnuts, grapes, melons, beans, berries, alfalfa, clover,
and vetch. Shade trees such as elm and black locust, ornamental shrubs
such as cotoneaster, and wild plants such as garrya, ceanothus, sun¬
flower, tarweed, morning glory, California poppy, milkweed, salvia, and
pigweed are also hosts.

No thorough investigation of the biology of Tetranychus pad ficus
has been published.

Tetranychus homorus Pritchard and Baker, new species
(Figures 341, 342)

The aedeagus of T etranychus homorus resembles that of T. pad ficus
very closely. However, specimens are known only from the far eastern
United States, and the integumentary striae of the female are longitu¬
dinal between the inner sacral setae. T. homorus may represent a
sub species of T. pacificus .

Male. — Palpus with terminal sensillum slender, about four times
as long as wide. Peritreme with long hook at distal end. Empodium I a
pair of trifid plates but slightly longer than the strong mediodorsal
spur; empodium II with obvious mediodorsal spur; empodia III and IV
each with the spur tiny but evident. Aedeagus with knob forming a
distinct angle with axis of shaft, slender, about three times as long
as neck of stem, the anterior angulation short, the caudal angulation
slender, tapering and reaching well beyond level of bend. Length of
body 300 p, including rostrum 370/i.

Female. — Palpus with terminal sensillum less than three times as
long as broad. Tarsus I with proximal duplex well distad of four tactile
setae. Empodia with mediodorsal spur rudimentary. Ilysterosoma with
transverse striae dorsally except for longitudinal striae between inner

391

Subfamily T etrany chinae Herlese

Fig. 343. Tetranychus schoeni: dorsal aspect of female.

392

Spider Mites

Fig. 344. Tetranychus schoeni: aedeagi.

sacrals. Area immediately anterior to genital flap with longitudinal
striae. Length of body 430 p, including rostrum 500 P ; greatest width
of body 290 p.

Holotype. — Male, Durham, North Carolina, June 18, 1953 (A. E.
Pritchard), on hickory; type no. 2182 in the U. S. National Museum.
Paratypes. — Two males, 4 females, Durham, North Carolina, June 18,
1953 (A. E. Pritchard), on hickory; 5 males, 7 females, Durham, North
Carolina, June 18, 1953 (A. E. Pritchard and Harvey Goldstein), on ash.

Tetranychus schoenei McGregor

(Figures 343, 344)

Tetranychus schoenei McGregor, 1941, Proc. Ent. Soc. Wash., 43: 223;
Pritchard and Baker, 1952, Hilgardia, 21(9): 266; Baker and
Pritchard, 1953, Hilgardia, 22(7): 216. Types: males and females,
Winchester, Virginia, on apple; in the U. S. National Museum.
Septanychus schoenei, McGregor, 1950, Amer. Midi. Nat., 44(2): 324.

The aedeagus of schoenei is distinctive among species of the genus
Tetranychus in that the distal knob is very large, about one-half as
long as the dorsal margin of the externa] shaft. The anterior angulation
of the knob is more or less broadly rounded, and the caudal angulation
is acute. The mediodorsal spur on empodium 1 (and 11) of the male is
obvious.

393

5

ub family l etranychinae Herlese

M -3 J

tig. 345. Tetrany chus canadensis : aedeagi.

The female resembles most other species of the Pacificus Group
in that the integumentary striae between the inner sacral setae are
longitudinal.

Tetrany chus schoenei is widely distributed over the eastern and
southwestern United States. Specimens have been studied from Mary¬
land, Virginia, West Virginia, Pennsylvania, Georgia, Alabama,
Mississippi, Louisiana, Missouri, and Oklahoma.

This species is sometimes a serious pest of apple, cotton, and
shade trees such as elm and black locust. Bean, bramble, raspberry,
wild plum, and buckberry are other hosts on which it has been taken.
Cagle (1943) presented an excellent study on the biology of this species.

Tetrarrychus canadensis ( McGregor )

(Figure 345)

Septanychus canadensis McGregor, 1950, Amer. Midi. Nat., 44(2): 319.
Types: males and females, Ontario, Canada, on apple; in the
U. S. National Museum.

Tetranychus canadensis, Pritchard and Baker, 1952, Hilgardia, 21(9):
267; Baker and Pritchard, 1953, Hilgardia, 22(7): 221.

The knob of the aedeagus of Tetranychus canadensis is a rather
miniature replica of T. schoenei. It is about one-third as long as the

394

Spider Mites

Fig. 347. Tetranychus Iambi: A.) tibia and tarsus I of female; R.l tibia
and tarsus II of female; (..) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

395

Subfamily T etrany chinae Berlese

Fig. 348. T etrany chus Iambi : A.) terminal segment of palpus of male; B.)
terminal segment of palpus of female; C.) empodium I of male; D.) termination
of peritreme; E.) empodium IV of male.

dorsal margin of tlie external shaft, the anterior projection being rounded
or somewhat angulate and the caudal projection forming an acute angle.
Empodia 1 and II of the male each possesses an obvious mediodorsal
spur.

The female bears longitudinal striae between the inner sacral setae,
and it is indistinguishable from other members of the Tacificus Group
with similar striae.

This species is widespread throughout the eastern and southwestern
United States and southeastern Canada. Specimens studied, other than
the types from Ontario, Canada, are from Connecticut, New Tork,New
Jersey, Washington, D. C., Maryland, \ irginia, Indiana, Ohio, Louisiana,
Mississippi, Tennessee, Kansas, Texas, and Arizona.

This species is sometimes of economic importance on apple, plum,
and cotton. Other hosts are elm, linden, horse chestnut, Osage orange,
poplar, rose, and umbrella tree. The only biological notes of this species
were published by Lienk and Chapman (1951).

396

Spider Mites

Tetrarvychus polys Pritchard and Baker, new species

(Figure 346)

Tlie aedeagus of Tetranychus polys resembles that of T. canadensis
except that it is smaller, about twice as wide as the stem. Moreover,
the empodium on tarsus I (and II) of the male does not possess a medio-
dorsal spur. The female bears more or less longitudinal striae on the
integument between the inner sacral setae, thus resembling the females
of T. schoenei, T. canadensis, and T. Iambi, but there is considerable
variation in these striae.

This species is known only from the Mojave Desert, in California.

Male. — Palpus with terminal sensillum slender, about four times
as long as broad. Peritreme with a short hook (or elbow) terminally.
Empodium I with stem about one-half as long as the pair of trifid divi¬
sions terminally, the teeth slender and the mediodorsal spur absent;
empodia III to IV without mediodorsal spur. Aedeagus with distal knob
very small, less than twice as wide as its stem, the anterior angulation
somewhat broader than the acute posterior angulation. Length of body
266 (x , including rostrum 345 p.

/' emalc. — Palpus with terminal sensillum about three times as long
as wide. Tarsus 1 with proximal duplex well beyond four tactile setae.

397

Subfamily I etranychinae Hrrlese

Fig. 350. Tetranychus desertorum : dorsal aspect of female.

Empodium without mediodorsal spur. Hysterosoma with transverse
striae across median line except for caudally directed angulations in
area arising between inner sacrals. Area immediately anterior to genital
flap with longitudinal striae. Length of body 300 p, including rostrum 400
p; greatest width of body 233 p.

398

Spider Mites

Fig. * 351. Tetrany chus descrtorum: A.) tibia and tarsus I of female; B.)
tibia and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus
of male.

Subfamily I e trany chiriae Berlese

Fig. 352. Yetranychus desertorum : A.) terminal palpal segment of male;
B.) temiinal palpal segment of female; C.) empodium I of male; D.) empodium I
of female.

Holotype. — Male, Mojave, California, August 11, 1945 (A. E.

Pritchard), on Atriplex sp.; type no. 2183 in the U. S. National Museum.
Paratypes. — Ten males, 39 females, Mojave, California, August 11,
1945 (A. E. Pritchard), on Atriplex sp.

Tetranycbus Iambi Pritchard and Baker , new species
(Figures 347, 348, 349)

The aedeagus of 7 etranychus Iambi is distinctive in that the distal
knob of the aedeagus is scarcely widened dorsoventrally, but the an¬
terior, and particularly the posterior, angulation is pronounced.
Empodium 1 of the male consists only of two, almost amalgamated,
trifid appendages, the mediodorsal spur being absent as in 7. polys,
and empodium 11 similarly lacks a mediodorsal spur. The female re¬
sembles other members of the Pacificus Group that have longitudinal
striae between the inner sacral setae.

This species is known only from New Zealand.

400

Spicier Mites

Fig. 353. T etrany chus des ertorum' aedeagus.

Male. — Palpus with terminal sensillum about four times as long
as broad. Peritreme with distal end strongly hooked. Empodium I con¬
sisting of two pairs of nearly united, trifid plates, the mediodorsal
spur absent; empodia II to IV without median spurs. Aedeagus with
axis of knob parallel to axis of shaft, slender, the anterior angulation
acute and pronounced, the caudal angulation very slender and acute.
Length of body 246p, including rostrum 313 p.

Female. — Distal sensillum of palpus about twice as long as wide.
Tarsus I with proximal duplex distal of four tactile setae. Empodia
each with mediodorsal spur absent, llysterosoma mediodorsal ly with
transverse striae except for longitudinal striae between and caudad of
inner sacrals. Area immediately anterior to genital flap, as well as

Fig. 354. Tetranychus gigas: aedeagus.

Subfamily I etrany chinae Herlese

Fig. 355. Tetranyctius deviatarsus : above, tibia and tarsus I
of female; below, tibia and tarsus II of female.

anterior portion of flap, with longitudinal striae. Length of body 320 g,
including rostrum 410 g; greatest w idth of body 233 g.

Holotype. — Male, Oratia, Auckland, New Zealand, March 11, 1953
(k. IN Lamb), on apple; type no. 2184, in the U. S. National Museum.
Paratypes. — hive males, four females, Oratia, Aukland, New Zealand.
March 11, 1953 (k. P. Lamb), on apple; 3 males, 5 fen, ales, Owairaka,
New Zealand, August 28, 1948 (K. P. Lamb), on strawberries in green¬
house.

402

Spider Mites

Fig. 356. Tetranychus deviatarsus : above, tibia and tarsus I
of male; below, tibia and tarsus II of male.

This species is named in honor of K. P. Lamb, the collector and
an entomologist keenly interested in the plant-feeding mites of ?>ew
Zealand.

Desertorum Group

I he Desertorum Group is based on species that exhibit a migration
of the proximal pair of duplex setae into line with the four tactile setae
on tarsus 1. I he peritreme ends in a simple hook, and the dorsal striae
of the female hysterosoma form a broad triangle between the third pair

403

Subfamily l e trany china? Merit's?

of dorsocentrals and the inner sacruls, the striae being longitudinal
between these setae. The mediodorsal spur of the empodium may be
rudimentary or apparent, but it is not as obvious as in most of the
lumidus Group.

hemales of species in this group are carmine, and tropical or sub¬
tropical in distribution. They are indistinguishable.

1 he three species assigned to this group are all similar except
with regard to the comparative enlargement of the distal knob of the
aedeagus. hemales that belong to this group have been received from
Iransvaal, Africa, on cotton, and from New Zealand, on greenhouse
tomatoes and strawberry. Males must be observed before their specific
identity can be ascertained.

Tetranychus desertorum Banks

(Figures 350, 351, 352, 353)

T etranychus desertorum Banks, 1900, Tech. Bui. U. S. Dept. Agr.
Div. Ent., 8: 76; Baker and Pritchard, 1953, Hilgardia, 22(7):
229, Types: males and females, Mesilla Park, New Fdexico, on
Larrea tridentata and Phacelia crenulata ; in the U. S. National
Museum.

7 etranychus opuntiae Banks, 1908, Proc. Ent. Soc. Rash., 10: 36.
Types : females, San Antonio, Texas, on Opuntia sp.; in the
U. S. National Museum.

T etranychus thermophilus Ewing, 1926, Ent. News, 37: 142. Types:
males, and females, Furnace Creek, Death Valley, California,
on ( Covillea ) - Larrea sp., in the U. S. National Museum.
Septanychus argentinus McGregor, 1943, Proc. Ent. Soc. Wash., 45:
176; McGregor, 1950, Atner. Midi. Nat., 44(2): 317. Types: males
and females, Argentina (at New Vork, Quarantine), on pear; in
the U. S. National Museum.

Septanychus deserticola McGregor, 1950, Amer. Midi. Nat., 44(2): 321.
Types; males and females, Palm Springs, California, on creosote
bush; in the U. S. National Museum.

Septanychus texazona McGregor, 1950, Amer. Midi. Nat., 44(2): 328.
Types; males and females, College Station, Texas, on turnip;
in the U. S. National Museum.

The aedeagus of T etranychus desertorum is typical of the Desertorum
Group in that the dorsal margin of the knob of the aedeagus is sigmoid,

404

Spider Mites

Fig. 357. Yetranyciius deviatarsus : A.) empodium I of female; B.)
empodium I of male; C.) empodium II of male.

the anterior angulation being small and acute and the posterior angula¬
tion being acute and curved ventrad to a variable extent. The width of
the aedeagal knob is not more than one-fourth as long as the dorsal
margin of the aedeagal shaft. The female is similar to that of other
females in the Desertorum Group.

This species is an important pest of cotton in Texas, and it is
widespread, although apparently only of local importance, throughout
other parts of the southern United States. Specimens have been received
from California, Arizona, New Mexico, Texas, Oklahoma, Louisiana,
Mississippi, Georgia, Florida, South Carolina, and North Carolina in
the United States, as well as from Tamaulipas and Coahuila in Mexico.
Collections from South America are from Peru and Argentina.

In addition to cotton, crops such as melons, cantaloupe, cucumber,
celery, carrots, turnips, and alfalfa are known to be subject to infesta¬
tion. Other records are from creosote bush, grass, wild tomatoes (Peru),
Stillingia sp., Opuntia sp., monkey flower, puncture vine, Eriodictyon
sp., sunflower, horseweed, and gladiolus.

Subfamily I etrcmychinae lierlese

Tetranychus gig as Pritchard and Baker , new species
(Figure 354)

Uie aedeagus of Tetranychus gigas resembles that of T. desertorum
except that the distal knob is considerably enlarged, being nearly one-
third as long as the dorsal margin of the shaft. Otherwise the characters
of both the male and female are as in T. desertorum.

lo date, this species is known only from western lexas and Arizona,
on cotton.

Male. — Terminal sensillum of palpus about three times as long as
wide. P eritreme very strongly retrorse distally. Empodium 1 with u
strong proximoventral, tapering tooth proximo ventrally on each side
and with a pair of finer, more medial teeth on each side, the mediodorsal
spur strong and nearly as long as the trifid appendages; empodium 11
w i th mediodorsal spur strongly developed; empodia Ill and IV each
with the mediodorsal spur small but obvious. Aedeagus with knob about
one-third as long as dorsal margin of shaft, the anterior angulation
acute and the caudal angulation acutely curved ventrad. Length of body
293 p, including rostrum 366 p.

Female. — Terminal sensillum of palpus about twice as long as
wide. Tarsus I with proximal duplex located level with the four tactile
setae. P.mpodia may have minute mediodorsal spur. Ilysterosoma with
striae forming a broad triangle between the third pair of dorsocentrals
and the inner sacrals, the striae being longitudinal between these
striae. Length of body 445 p , including rostrum 566 g; greatest width
of body 280 g.

llolotype. — Male, Sahuarita, Arizona, July 8, 1953, on cotton; type
no. 2185, in the U. S. National Museum. Paratypes. — One male, 6 fe¬
males, Sahuarita, Arizona, July 8, 1953, on cotton; 12 males, 36 females,
Crosby County, lexas, July 9-20, 1953, on cotton.

Tetranychus ludeni Zacher
(Figures 355, 356, 357, 358)

7 etrany chus ludeni Zacher, 1913, Mitt. kais. biol. Anst. Land-Forstw.,
14: 40; Zacher, 1921, Zts. ang. Ent., 7: 187; McGregor, 1919,
Proc. L. S. Natl. Mus., 56(2303): 653; Ilardouin, 1934, Bui.
Soc. Ent. France, 39: 123. Described from specimens from St.
Cloud, near Paris, France, on Salvia splendens, Solanum
melongena, and Cucurbita sp.

406

Spider Mites

T etranychus ( Epitetranychus ) ludeni, Zacher, 1921, Zts. ang. Ent.,
7: 187; JIardouin, 1934, Bui. Soc. Ent. France, 39: 123, Andre,
1934, Bui. Hist. Nat. Paris (ser. 2), 6(40): 348.

T etranychus salviae Oudemans, 1931, Ent. Ber., 8(177): 230. Types :
3 females, possibly from Paris, France, on Salvia splendens;
possibly in the Kijksmuseum van Natuurlijke llistorie, Leiden,
Holland. New synonymy.

Septanychus deviatarsus McGregor, 1950, Amer. Midi. Nat., 44(2): 322.
Types: males and females, Anaheim, California, on castor bean;
in the U. S. National Museum.

Fig. 358. Tetranychus deviatarsus :
aedeagus.

The aedeagus of T etranychus
ludeni resembles that of T. desertorum
except that the distal knob of the
aedeagus is very small, scarcely
larger than the stem, and the pos¬
terior angulation is absent. The
female is indistinguishable from
other members of the Desertorum
Group.

This species is encountered
occasionally out of doors in the
southern United States, collections
being from southern California and
Louisiana. Specimens have also
been found in greenhouses in northern
California and in Missouri. Zacher’s
specimens were from greenhouses near
Paris, France, on several different
hosts.

The Louisiana material, collected
by H. Bruce Boudreaux, is from
cotton. Outdoor collections from
southern California are from Carlsbad
(A. E. Pritchard), on lantana, Los
(C. A. Hanson); on Ken-
wonder beans; and Santa
(C. A. Fleschner), on castor
Bay region, California, are
and Datura sp. South
Chile (A. E. Michelbacher),
R. King), on kudzu; San Salvador,

Angeles
tucky
Paula

bean. Collections from the San Francisco
from greenhouses (A. E. Pritchard), on lantana
American specimens studied are from Catema,
on castor bean; Concordia, Argentina (J.

407

Subfamily 7 etrany chinae Herlese

/

/

Fig. 339. / etranychus tunidus : tarsus I of female.

El Salvador (Ross), on Cosmos sp. Still other collections have been
received from Taringo, Australia (E. H. Derrick), on Convolvulus sp.;
and Australia (Maehler and Ross, at Hawaiian quarantine), on celery.

On one of Zacher’s slides that Oudemans studied, three out of 21
specimens were larger and with longer legs, longer setae, and larger
eyes. These specimens formed the basis for Tetranychus salviae
Oudemans, but we are unable to appreciate the differentiation from
T. ludeni.

The placing of deviatarsus into synonymy with ludeni is based upon
the study of one of Zacher’s slides from the Oudemans’ collection loaned
us through the courtesy of Dr. H. Boschma.

408

Spider Mites

Tumidus Group

Mites belonging to the Tumidus Group may be recognized by having
an obvious mediodorsal spur on the empodium and the proximal pair
of duplex setae on tarsus 1 placed distad of the proximal tactile setae.
In I etranychus cocosi and T. cocosinus the empodial spur is consider¬
ably smaller than in the other species, but it is easily seen. These
species are included in the lumidus Group because the aedeagus re¬
sembles that of certain species belonging to this group and they are
apparently very closely related.

The hysterosoma of the female bears a diamond-shaped pattern in
the area between the third pair of dorsocentrals and the inner sacrals,
the striae being longitudinal in the interval between each of these
pairs of setae. Adult females are carmine, and they are for the most
part indistinguishable.

The species are tropical or subtropical in distribution.

Tetrarrychus tumidus Banks
(Figures 359, 360)

1 etranychus tumidus Banks, 1900, U. S. Bept. Agr. Tech. Ser., 8: 73;
Baker and Pritchard, 1933, Ililgardia, 22(7): 232. Types: females,
Eustis, Florida, on water hyacinth; in the U. S. National Museum.
Septanychus tumidus, McGregor, 1919, Proc. U. S. Natl. Mus., 56(2303):

664; McGregor, 1950, Amer. Midi. Nat., 44(2): 326.

T etranychus gloveri. Banks, 1900, U. S. Dept. Agr. lech. Ser., 8: 76.
Types: females, Baton Rouge, Louisiana, on cotton; in the U. S.
National Museum.

T etranychus quinquenychus McGregor, 1914, Ann. Ent. Soc. Amer.,
7(4): 358. Types: females, Orlando, Florida, on castor-bean;
in the U. S. National Museum.

Septanychus quinquenychus, McGregor, 1919, Proc. U. S. Natl. Mus.,
56(2303): 664.

Tetranychus antillarum Banks, 1917, Ent. News, 28: 194. Types: females,
Rio Piedras, Puerto Rico, on Lconotis nepetacfolia and Asclepias
curassavica\ in the E. S. National Museum.

The male of 7 etranychus tumidus may be recognized by having the
anterior development of the aedeagal knob broadly rounded, together
with having an obvious empodial spur on tarsi 111 and IV. The caudal
development of the aedeagal knob is short and acutely angulate.

Subfamily T etranychinae lierlese

Tetranychus tumidus is foutul commonly in the southeastern United
States, and collections have been studied from Florida, Georgia, South
Carolina, Louisiana, and southeastern lexas. It also occurs in Puerto
It i co, and McGregor ( 1950) recorded specimens from Guam. In California,
this species is often a greenhouse pest (Pritchard, 1949).

lhis species is a serious pest of cotton (Rousel et al., 1952) as
well as vegetable crops such as celery, beans, eggplant, beets, okra,
peas, and sweet potato. It is also very destructive to commercial crops
of potted ornamentals such as palms, maranta, and bamboranta. We
have accumulated a long list of other low-growing plants that serve
as hosts.

Tetranychus tumidel lus Pritchard and Baker, new species
(Figures 361, 362, 363)

Tetranychus tumidellus is closely allied to T. tumidus from which
it differs only by having the terminal knob of the aedeagus very tiny.
I h is species is known only from the southeastern United States.

Male. — Palpus with terminal sensillum about three times as long
as broad. Peritreme with a long distal hook. Empodium 1 with a pair
of trifid plates, the teeth minute, and with a mediodorsal spur nearly
as long as the appendages; empodia I I-I \ each with the dorsal spur
nearly one-half as long as the proximal hairs. Aedeagus with ventral
margin gradually curved dorsad, the terminal knob only slightly wider
than its stem and with posterior and anterior angulations similar, acute.
Length of body 300 p, including rostrum 390 p.

Female. — Similar. Terminal sensillum of palpus about twice as long
as wide. Tarsus I with proximal duplex located distad of the four tactile
setae. Empodia each with mediodorsal spur nearly one-half as long as
proximoventral hairs, llysterosoma with longitudinal striae between both
the third pair of dorsocentrals and the inner sacrals. Anterior portion
of genital flap and area immediately anterior to genital flap with longi¬
tudinal striae. Length of body 366 p, including rostrum 433 p; greatest
width of body 280 p.

410

Spider Mites

Kig. 361. Tetranychus tumidellus : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus 1 of male; D.) tibia and tarsus II
of male.

411

Subfamily T etrany chinae Htrlcse

Fig. 362. Tetranycnus tumidellus: A.) terminal segment of palpus of female;
B.) terminal segment of palpus of male; C.) empodium I of female; D.) empodium
1 of male.

Holotype. — Male, lift County, Georgia, July 23, 1948 (P. W. Gilmer),
on peanut vines; type no. 2186 in tlie U. S. National Museum. P aratypes.
— Forty ftiales, 93 females, Tift County, Georgia, July 23, 1948

(P. Vi. Gilmer), on peanut; 9 males, 49 females, Union Springs, Alabama,
August 23, 1949 (F. S. Arant), on peanut; 2 males, 8 females, Bullock
County, Alabama, September 15, 1949 (F. S. Arant), on peanut.

Tetranychus mexi canus (McGregor), new combi nation
(Figures 364, 365, 366, 367)

Septanychus mexi canus McGregor, 1950, Amer. Midi. Nat., 44(2): 323.
Types: males and females, Mexico (at Laredo, Texas, quarantine),
on orange; in the U. S. National Museum.

412

Spider Mites

Fig. 363. Tetranychus tumidellus: aerieagus.

The male of Tetranychus mexicanus may be differentiated from other
members of the Tumidus Group that have a large empodial spur by having
the axis of the knob of the aedeagus parallel to the axis of the shaft,
and with the anterior angulation short and acutely angulate and the
posterior angulation considerably longer and acutely angulate.

This species is known from the type specimens found on orange being
shipped from Mexico; Valles, Mexico (II. D. Smith), on citrus; Monte
Alto, Texas (II. A. Dean), on lemon; and Concordia, Argentina (J. King),
on citrus.

Tetranychus magnoliae Boudreaux

(Figures 368, 369)

Tetranychus magnoliae Boudreaux, 1954, Pan-Pac. Ent., 30: 184.
Uolotype : male, Baton llouge, Louisiana, on Magnolia grandi flora;
in the U. S. National Museum.

113

Subfamily ietranychinne Berlese

Fig. 364. Tetranyclius mexicanus : above, tibia and tarsus I of
female; below, tibia and tarsus II of female.

T etranychus magnoliae is closely allied to T. mexicanus from which
it differs in having the axis of the knob of the aedeagus forming an angle
with the axis of the shaft. The terminal angulation of the knob is slen¬
derer and longer than in 7. mexicanus.

This species is known only from southern Louisiana on magnolia
and tulip tree. Adult females are carmine. They spin dense webbing on
the upper surface of magnolia leaves but inhabit both surfaces of the
tulip tree leaf.

414

Spider Mites

Fig. 365. Tetranychus mexicanus ■ above, tibia and tarsus I of
male; below, tibia and tarsus II of male.

Tetranychus cocos/ (McGregor), new combination
(Figures 370, 371, 372)

Septanychus cocosi McGregor, 1950, Amer. Midi. Nat., 44(2): 320.
Types : males and females, Whittier, California, on royal palm;
in the IJ. S. National Museum.

The aedeagus of Tetranychus cocosi resembles that of T. mexicanus
in that the aedeagal knob, with an axis parallel to the axis of the

•U5

Subfamily 7 etranychinae Merles?

Hg. 366. Tetranychus mexicanus : above, empodium IV of
female; below, empodium I of female.

Fig. 367. Tetranychus mexicanus : aedeagus.

416

Spider Mites

Fig. 368. Tetranychus magnoliae : A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of mal e.

417

Subfamily T etrany chinae Herlese

Fig. 369. T etrany chus ma&noliae'- aedeagus.

shaft, bears slender angulations both anteriorly and posteriorly. The
caudal angulation is somewhat the longer. The terminal sensillum on
the palpus of the male is parallel-sided, about three times as long
as wide at the base. 1 he mediodorsal empodial spur of both sexes is
small but quite evident, and in this respect, T etrany ck us cocosi is
rather intermediate between the Tumidus and lelarius Groups. I he
adult female is carmine.

I his species is known only from southern California. Recently
collected material is from Fullerton, California (A. E. Pritchard), on
royal palm; San Diego, California (A. E. Pritchard), on royal palm;
and Coronado, California (A. E. Pritchard), on bamboo.

T etrany chus cocos inus Boudreaux
(Figures 373, 374)

7 etrany chus cocosinus Boudreaux, 1954, Pan-Pac. Ent., 30: 182.
liolotype : male, Port Allen, Louisiana, on Celtis sp.; in the
U. S. National Museum.

This species is closely allied to Tetranychus cocosi, similarly
having the knob of the aedeagus parallel to that of the shaft and with
both the anterior and posterior angulations slender. However, the poste¬
rior angulation is twice as long as the anterior angulation. Moreover,
the terminal sensillum on the palpus of the male is somewhat clavate
and nearly five times as long as the proximal width. The female is
dark purple in life.

T etrany chus cocosinus is known only from the types from southern
Louisiana, on brambles, hackberry, rose, and American elm.

418

Spider Mites

Telarius Group

Mites belonging to the Telarius Group of the genus Tetranychus
have the mediodorsal spur of the empodium tiny or absent; and the
proximal pair of duplex setae on tarsus I is distal to the four tactile
setae at the base of the segment. The female has longitudinal striae
on the integument between the third pair of dorsocentral hysterosomals
and also the inner sacrals, and a diamond-shaped figure is formed in
the area between these setae.

Adult feeding females occurring naturally in the temperate zones
are greenish. However, most of the species are found in tropical or
subtropical areas, and their females are carmine.

419

Subfamily 7 etrany chinae Berlese

Hg. 371. T etrany ctius cocosi : A.) tibia and tarsus II of female; R.)
tibia and tarsus I of male; C.) tibia and tarsus II of male.

Tetranychus cucurbitae Rahman and Punjab
(Figures 375, 376, 377)

Tetranychus cucurbitae Rahman and Punjab, 1940, Proc. Indian Acad.
Sci. (ser. B), 11: 179; Rahman and Sapra, 1946, Indian Jour.

420

Spider Mites

Agr. Sci., 15(3): 124. Types: males and females, Lyallpur, India,
on pumpkins ( Cucurbita maxima, C. pepo, and C. moschata),
Citrullus vulgaris var. fistulosus, Luffa aegyptica, cabbage
( Brassica oleracea), tomato ( Lycoperciscum esculentum), and
hollyhock ( Althaea rosea), as well as many others, totaling about
sixty different plants.

Tetranychus equatorius McGregor, 1950, Amer. Midi. Nat., 44(2): 285.
Types : males and females, Waipahu School, Oahu, Hawaiian
Islands, on string beans; in the U. S. National Museum. New
synonymy.

Tetranychus cucurbitae may be
readily recognized by the aedeagal
knob, which is berrylike with the
anterior curvature more strongly
developed than the posterior con¬
vexity. The adult female is carmine.

Specimens from India have been
studied that are undoubtedly refer-
rable to this species. They are the
same as Tetranychus equatorius.

McGregor recorded this species
from several of the Hawaiian Islands,
the Fiji Islands, Venezuela, and
Puerto Rico. Recorded hosts are
Cinchona sp., Cracca vogeli,
Grammatophyllum sp., peanut, string
bean, water hyacinth, and water¬
melon.

New collections studied by us
are from Honolulu, Oahu, Territory
of Hawaii (F. S. Morishita), on
mango; Bahamas (at Hoboken, New
Jersey quarantine; McMaster), on
Codiaeum sp.; Coral Gables, Florida
(F. G. Butcher and A. E. Pritchard), on papaya and Bauhinia alba;
P t. Lauderdale, Horida (0. 1). Link), on Buddlcia asiatica; Ft. Lauder¬
dale, Florida (C. Poucher), on Maranta sp.; Geneva, Florida (0. D.
Link), on Chinaberry; Northport, Long Island, New York (G. V. Johnson),
on sweet potato in greenhouse; South America (at Honolulu, quarantine;
Yokoyama), on Cynoches sp.; and Mysore, India (M. Puttarudriali),
on bean.

Fig. 372. Tetranychus cocosi:
aedeagus.

421

Subfamily T ttrany chinae Herlesr

Fig. 373. Tetranychus cocosinus: A.) tibia and tarsus I of female; If.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of mal e.

422

Spider Mites

Fig* 375* Tetranychus cucurbitae: A.) empodium I of female; B.) empodium
1 of male; C.) tibia and tarsus I of female.

423

Subfamily 1 etranychinae Herlese

Fig. 376. 7 etrany ckus cucurbitae : A.) tibia and tarsus II of female; B.)

tibia and tarsus I of male; C.) tibia and tarsus II of male.

424

Spider Mites

Fig. 377. Tetranychus cucurbitae: aedeagus.

Tetranychus atlanticus McGregor
(Figure 378)

Tetranychus atlanticus McGregor, 1941, Proc. Ent. Soc. Wash., 43: 26;
McGregor, 1950, Amer. Midi. Nat., 44(2): 280; Pritchard and
I3aker, 1952, Ililgardia, 21(9): 271; Baker and Pritchard, 1953,
Bilgardia, 22(7): 227. Types: males and females, Chadbum,
North Carolina, on strawberry; in the U. S. National Museum.

Tetranychus atlanticus may be recognized by having the distal
knob of the aedeagus moderately enlarged, about one-fourth as long
as the dorsal margin of the shaft, and with the dorsal margin of the
knob obtusely angulate. The anterior projection of the knob is broad
and narrowly rounded, and the posterior angulation is small and acute.
The axis of the knob usually forms an angle with the axis of the shaft.
Actively feeding females are strawcolored or greenish with a pair of
large black spots near the middle of the body.

This spider mite is found throughout most of the United States,
but it appears to reach greatest abundance in the West. Records are
from New York, Connecticut, Maryland, Delaware, Virginia, South

425

Subfamily 1 etrany china? Merit's?

Fig. 378. Tetranychus atlanti cus: aedeagi.

Carolina, Kentucky, Georgia, Florida, Alabama, Mississippi, Louisiana,
Ohio, Wisconsin, Utah, Idaho, Oregon, and California.

Tetranychus atlanticus is found primarily on low-growing plants.
It is a serious pest of cotton, alfalfa, beans, melon, clover, straw¬
berry, parsley, and eggplant. Many weeds serve as hosts. Occasional
collections are taken on pear, peach, apple, walnut, and lemon.

One collection was forwarded from Ankara, Turkey (Zeliha Diizgiines),
on apple; and another collection from Okitsu, Shiznoka, Japan (Jiro
Fukuda), on apple.

Tetranychus hydrangeae Pritchard and Baker, new species
(Figure 379)

The knob of the aedeagus of Tetranychus hydrangeae is moderately
enlarged as in /. atlanticus but the dorsal margin of the knob is convex,
not angulate. The anterior, rounded projection of the knob is about
as wide as the base of the acute posterior angulation, and the axis of
the knob is parallel to that of the shaft.

Fig. 379. Tetranychus hydrangeae: aedeagus.

426

Spider Mites

Fig. 300. Tetranychus merganser: A.) tibia and tarsus I of female; B.) tibia
and tarsus II of female; C.) tibia and tarsus I of male; D.) tibia and tarsus II
of male.

427

Su b fam ily l e truri v cfi in a e H e rlese

l he adult female, and also the male, is carmine in color, and hy¬
drangea is the most important host.

Male. — Palpus with terminal sensillum subclavate, nearly five
times as long as broad at base. Peritreme strongly retrorse distally.
Lmpodium I with two trifid appendages having slender digits, the medio-
dorsal spur strong; empodium II with mediodorsal spur strong; empodia
111 and IV each with tiny but apparent spur. Aedeagus with dorsad bend
t nearly right angle; knob about one-fifth as long as shaft, its axis
parallel to that of shaft, the anterior projection rounded and no wider
at base than base of the acute posterior projection. Length of body
330 p, including rostrum 450 p.

Female. — Similar, Terminal sensillum of palpus about three times
as long as wide at base. Tarsus 1 with proximal duplex distal to four
proximal tactile setae. Empodia with tiny mediodorsal spur. Ilysterosoma
with longitudinal striae between third pair of dorsocentrals and between
inner clunals. Area immediately anterior to genital flap with longitudinal
striae. Length of body 375 p, including rostrum 500 p; greatest width
of body 300 p.

Holotype. — Male, Los Angeles, California, February 15, 1952 (11. N.
Jefferson), on bean; type no. 2187 in the U. S. National Museum. Para-
types. — Twenty-four males, 12 females, San Francisco, California,
October 22, 1949 (A. F.. Pritchard), on hydrangea in greenhouses; 1
male, 1 female, December 15, 1951 (A. E. Pritchard), on poinsettia
in greenhouse; 4 males, 5 females, Los Angeles, California, July 18,
1949 (R. N. Jefferson), on Maranta sp. in greenhouse; Los Angeles,
California, February 14, 1952 (R. N. Jefferson), on beans.

This species is an important pest of hydrangeas, particularly potted
plants grown commercially in greenhouses. Davis (1952), by transfers
in the laboratory, showed that the mites could live and reproduce on
bean, strawberry, and violets, but are unable to survive on banana
squash. Poinsettia is not a favorable host, the colonies remaining
very small and often disappearing under warm greenhouse conditions.

428

Spider \1ites

Fig. 382. Tetranycnus marianne : A.) tibia and tarsus I of female; R.) tibia
and tarsus II of female; C. ) tibia and tarsus 1 of male; 13.) tibia and tarsus II
of male.

429

Subfamily Tetranychinae fieriest ‘

vVV

Fig. 383. Tetranychus marianae : above, empodium I of
male; below, empodium I of female.

Tetranychus merganser Boudreaux
(Figures 380, 381)

T etranychus merganser Boudreaux, 1954, Pan-Pac. Ent., 30: 181.
Holotype : male, Baton Rouge, Louisiana, on Ligustrum vulgare ;
in the U. S. National Museum.

The knob of the aedeagus is moderately enlarged with the dorsal
margin convex, thus resembling T etranychus hydrangeae. However,
the evenly rounded anterior projection of the aedeagal knob of T.
merganser is very broad in comparison with the acute caudal angu-
1 ation.

The female is carmine. In contrast to Tetranychus hydrangeae and
T. atlanticus, the anterior portion of the genital flap bears longitudinal
striae.

This species is known only from Louisiana, on privet.

Tetranychus marianae McGregor
(Figures 382, 383, 384)

T etranychus marianae McGregor, 1950, Amer. Midi. Nat., 44(2): 291;
Baker and Pritchard, 1953, llilgardia, 22(.): 229. Types: males
and females, Mt. Lasso, Tinian Island, Mariana Group, on
Passiflora foetida; in the U. S. National Museum.

430

Spider Mites

Fig. 384. Tetranyciius marianae: aedeagus.

T etranychus marianae may be recognized by the aedeagus, the
axis of the terminal knob forming a definite angle with the axis of
the shaft, with a small anterior angulation and with a longer, dorso-
caudally directed angulation. The knob is obviously longer than the
stem. Adult females are carmine in life.

McGregor recorded this species from Saipan, and the Tinian Islands
on castor bean, passion flower, and Melanolepis multiglandulosa.
Additional specimens studied by us are from Iwo-Arno Atoll (R. L.
Usinger), on 1 Vedelia sp.; Concordia, Argentina (J. R. King), on night¬
shade; Chinandega, Nicaragua (R. B. Swain), on cotton; Managua,
Nicaragua (R. Pinell), on cotton; Key West, Florida (E. ft. Baker), on
wild lavender; and Miami, Florida (0. D. Link), on Triumfetta semitriloba.

Tetranychus neocaledoni cus Andre

T etranychus neocaledoni cus Andre, 1933, Bui. Mus. Hist. Nat. Paris
(ser. 2), 5: 302. Types: females, New Caledonia, on cotton;
probably in the Museum d’ Kistoire Naturelle de Paris.

Andre’s description of T etranychus neocaledonicus is based on
the female alone, and F. Cohic, the entomologist of the island, has
been unable to find topotype males on which we might base determina¬
tion of the species. The original host, cotton, is no longer a commercial
crop on the island.

Fig. 385. Tetranychus piercei: aedeagus.

431

Subfamily I etranyehinae Herlese

Our knowledge to date indicates that this name preoccupies that
of either l etranychus marianae or T. cucurbitae.

Tetranychus piercei McGregor

(Figure 385)

l etranychus piercei McGregor, 1950, Amer. Midi. Nat., 14(2): 299.
lype: male, Victorias Occ. Negros, Philippine Islands, on
Clitoria temata ; in the U. S. National Museum.

I etranychus piercei appears to be closely related to 7. marianae,
but the aedeagal knob is diminutive and much smaller than the base of
the stem that supports it. 1 he only male is in very poor condition, and
this species may prove to be a synonym of 7. marianae. Only the type
from the Philippine Islands is known.

Tetranychus dugesii Cano y Alcacio

I etranychus dugesii Cano y Alcacio, 1886, Naturaleza, 7(12): 197.
Described from specimens from Hacienda Escuela (probably near
Mexico City), Mexico, on Medicago denticulata.

lhe reddish coloration of the female indicates that this species
belongs to the genus T etranychus, even though Cano y Alcacio’s figure
of the empodial appendages is more suggestive of Schizotetrany chus.
Identification will have to be based on topotype material.

Tetranychus kanzawai Yokoyama

I etranychus kanzawai Vokoyama, 1927, Zool. Mag., 39(460): 105. De¬
scribed from male and female, Japan, on mulberry.

The aedeagus of Tetranychus kanzawai, as figured bv Yokoyama. is
distinctive. The distal knob is about one-third as long as the shaft,
with a small, dorsally projecting angulation on the anterior, rounded
development, and with the caudal angulation acute.

432

Spider Mites

Fig. 386. Tetranychus telarius: female with indications
of body markings when feeding.

Tetranychus telarius ( Linnaeus )

(Figures 386, 387, 388, 389, 390, 391)

Acarus telarius Linnaeus, 1758, Syst. Nat., 10: 616; Oudemans, 1931,
Ent. Her., 8(177): 221. Described from specimens from Sweden,
on various hosts and 7 ilia sp.

433

Subfamily T e trany chinae Herlese

Fig. 387. Tetranychus telarius: dorsal aspect of non-feeding female.

Tetranychus telarius, Duges, 1834, Ann. Sci. Nat. Paris (ser. 2), 1: 15;
Donnadieu, 1875, Ann. Soc. Linn. Lyon (n. ser.), 22: 151; Murray,
1877, Econ. Ent. Apt., p. 97; Canestrini, 1889, Atti Beale 1st.
\ en. Sci. Let. Arti (ser. 6), 7: 497; Banks, 1900, U. S. Dept.
Agric. Div. Ent. lech. Ser., 8: 75; Ewing, 1914, Bui. Oreg. Agr.
Expt. Sta., 121: 1; Tragardh, 1915, Meded. Centralanst. forsoks
jordbruks. Ent. avd., 20 : 40; McGregor, 1917, U. S. Dept. Agric.
Farm. Bui., 831: 3, 40; McGregor, 1919, Proc. L. S. Nat!. Mus.,
56(2303): 650; Hirst, 1920, Proc. Zool. Soc. Lond., 1920: 49;
Hirst, 1924, Ann. Mag. Nat. Hist. (ser. 9), 14: 621.

434

Spider Mites

Fig. 388. Tetranychus telarius : dorsal aspect of actively feeding female

435

Subfamily I etruny chinae Herlesc

Fig. 389. Tetranychus telarius : above, tibia and tarsus I of
female; below, tibia and tarsus II of female.

Acarus sambuci Schrank, 1781, Enum. Ins. Austr., p. 521. Described
from specimens from Germany, on Sambucus.

7 etranychus sambuci, Koch, 1842, Ueber Arachn. Syst. Fam. 3, p. 37;
Oudemans, 1930, Ent. Der., 8(176): 168; Oudemans, 1937, Krit.
Hist. Overz. Acar. , 3(C): 1043; Geijskes, 1939, Meded. Land-
bouwh. ftageningen, 42(4): 37.

436

Spider Mites

Fig. 390. Tetranychus telarius: above, tibia and tarsus I of
male; below, tibia and tarsus II of male.

Epitetranychus sambuci, Oudemans, 1931, Ent. Ber., 8(177): 194.

Acarus textor Fourcroy, 1785, Ent. Paris, 2: 530. Described from speci¬
mens from France, on bark of tree.

Tetranychus textor , Oudemans, 1929, Krit. Hist. Overz. Acar., 2: 276.

Tetranychus lintearicus Dufour, 1832, Ann. Sci. Nat. Paris, 25: 276 —
also spelled as lintearius on p. 281; Canestrini and Fanzago,
1878, Atti Reale Istit. Ven. Sci. Let. Arti (ser. 5), 4: 148; Hirst
1920, Proc. Zool. Soc. Lond., 1920 : 56; Oudemans, 1931, Ent.
Her., 8(177): 196; Oudemans, 1937, Krit. Hist. Overz. Acar.,
3(C): 1038. Described from specimens from Saint-Sever, France,
on Ulex europaeas.

Tetranychus urticae Koch, 1836, Deu. Crust. Myr. Arach., 1: 10;
Oudemans, 1931, Ent. Her., 8(177): 231; Oudemans, 1931, Ent.

437

Subfamily letrany china e H crime

Iht., 8(180): 276; Geijskes, 1939, Meded. I.andbouwh. Wagen-
ingen, 42(4): 36; Womersley, 1940, Trans. Hoy. Soc. S. Australia,
64: 256; Heck, 1950, hudy lust. Zool. Akad. Nauk Gruz. S.S.H.,
9; 127. Described from specimens from Hegensburg, Germany,
on nettle.

Tetranychus urticae dianthica Dosse, 1952, Hofchen-BHefe, 5: 250.
l)e scribed from specimens from Germany, in greenhouse, on
carnation. New synonymy.

7 etranychus russeolus Koch, 1838, Deu. Crust. Myr. Arach., 17: 15;
Oudemans, 1937, krit. Hist. Over/. Acar., 3(C): 1042. Described
from specimens from Germany, on nettle.

Tetranychus viburni Koch, 1838, Deu. Crust. Myr. Arach., 17: 17.
Described from specimens from Germany, on Viburnum opulus.

Sch izotetranychus vibumi, Oudemans, 1937, Krit. Hist. Overz. Acar.,
3(C): 1061.

I etranychus fervidus Koch, 1841, Deu. Crust. Myr. Arach., 37: 21;
Oudemans, 1937, Krit. Hist. Overz. Acar., 3(C): 1037. Described
from specimens from Germany, in moss.

Acarus cucumeris Boisduval, 1867, Ent. Ilort. , p. 84. Described from
specimens from France, on cucumber.

I etranychus cucumeris, Murray, 1877, Econ. Ent. Apt., p. 102.

Acarus rosarum Boisduval, 1867, Ent. Ilort., p. 84 Described from
specimens from France, on rose.

1 etranychus rosarum, Murray, 1877, Econ. Ent. Apt., p. 102.

Acarus cinnabarinus Boisduval, 1867, Ent. Hort., p. 88. Described from
specimens from France, in greenhouse on Dracaena.

Acarus haematodes Boisduval, 1867, Ent. Ilort., p. 88. Described from
specimens from France, on castorbean.

Tetranychus telarius haematodes, Murray, 1877, Econ. Ent. Apt., p. 101.

Hearns ferrugineus Boisduval, 1867, Ent. Hort., p. 90. Described from
specimens from France, in greenhouse on cyclamen.

I etranychus ferrugineus Murray, 1877, Econ. Ent. Apt. p. 103.

Acarus vitis Boisduval, 1867, Ent. Hort., p. 92. Described from speci¬
mens from France, on grape.

T etranychus vitis, Murray, 18 <7, Econ. Ent., Apt. p. 103.

Distigmatus pilosus Donnadieu, 1875, Rech. Serv. Hist. Tetran., p. 118.
Described from specimens from France, on prune, peach, and
other rosaceous trees.

T etranychus major Donnadieu, 1875, (not Duges, 1834), Rech. Serv.
Hist. Tetran., p. 120. Described from specimens from France, on
vegetation, particularly trees.

T etranychus piger Donnadieu, 18^5, Rech. Serv. Hist. letran., p. 121,

438

Spider Mites

Described from specimens from France, on elm and paper-
mulberry.

7 etranychus minor Donnadieu, 1875, Rech. Serv. Hist, detran., p. 121.
Described from specimens from France; no host given.

T etranychus longitarsus Donnadieu, 1875, Rech. Serv. Hist. Tetran.,
p. 122. Described from specimens from France; no host given.

7 etranychus plumistoma Donnadieu, 1875, Rech. Serv. Hist. Ietran.,
p. 122. Described from specimens from France, on herbaceous
plants. New synonymy.

T etranychus fici Murray, 1877, Econ. Ent. Apt., p. 107. Described from
specimens from near London, on fig. New synonymy.

T etranychus eriostemi Murray, 1877, Econ. Ent. Apt., p. 109. Described
from specimens from England, in greenhouse, on Erios temon
verii folium. New synonymy.

T etranychus inaequalis Targioni Tozzetti, 1878, Ann. Agr., 1: 251.
Described from specimens from Italy, on many greenhouse plants.

7 etranychus bimaculatus Harvey, 1893, Ann. Rep. Maine Agr. Exp.
Sta. 1892: 133; McGregor, 1912, U. S. Dept. Agr. Lire., 150: 1;
McGregor, 1917, U. S. Dept. Agr. Bui., 416: 3; McGregor, 1919,
Proc. U. S. Nat. Mus., 56(2303): 654; Garman, 1940, Conn. Agr. Exp.
Sta. Bui., 431: 81; McGregor, 1942, Proc. Ent. Soc. Wash., 44:
28; McGregor, 1950, Amer. Midi. Nat., 44(2): 281; Pritchard and
Baker, 1940, 1952, Hilgardia, 21(9): 268; Baker and Pritchard, 1953,
Ililgardia, 22(7): 221. Described from specimens from Orono,
Maine, on numerous hosts.

7 etranychus altheae von Ilanstein, 1901, Zts. wiss. Zool., 70: 74;
dragardh, 1915, Midd. Central anst. fbrsoks jordbruks, Ent. avd.,
109(20): 36; Oudemans, 1930, Ent. Ber., 8(175): 163.

Epitetranychus altheae, Zacher, 1916, Mitt, kaiserl. biol. Anst. Land-
Forstw., 16: 23; Oudemans, 1931, Ent. Ber., 8(177): 193.

Epitetranychus hamatus Zacher, 1916, Mitt, kaiserl. biol. Anst. Land-
Forstw., 16: 25. Described from male and female specimens

from Germany, on Euphorbia ; possibly in the Zacher collection.

New synonymy.

Epitetranychus aequans Zacher, 1916, Mitt, kaiserl. biol. Anst. Land-
borstw., 16: 25. Described from male and female specimens

from Germany, on mint; possibly in the Zacher collection. New
synonymy.

Epitetranychus alceae Oudemans, 1928, Ent. Ber., 7(159): 290. De¬
scribed, and erroneously accredited to Linnaeus, 1758, not

1746, from specimens from Holland, on Althea rosea. New
synonymy.

139

Subfamily T etrany ehinae Htrlese

Tetranychus reinwardtiae Oudeinans, 1930, hint. Her., 8(175): 170.
types: male and female, Stockholm, Sweden, in greenhouse on
Keinwardtia tetragyna ; probably in the Rijksmuseum van Natuur-
lijke llistorie, Leiden, Holland. New synonymy.

Epitetranychus reinwardtiae, Oudeinans, 1931, Knt. Her., 8(177): 194.

Epiteh any chus caldarii Oudemans, 1931, Ent. Her., 8(177): 194. types:
female, Stockholm, Sweden, in greenhouse, on unknown host;
probably in the Rijksmuseum van Natuurlijke llistorie, Leiden,
lloll and. New synonymy.

tetranychus ( Epitetranychus ) caldarii, Geijskes, 1939, Meded. Land-
bouwh. Wageningen, 42(4): 40.

Tetranychus fragariae Oudemans, 1931, lint. Her., 8(17H): 226; Geijskes,
1939, Meded. Landbouwh. Wageningen, 42(4): 37. types: male
and female, Holland, on Tragaria vesca; probably in the llijks-
museum van Natuurlijke llistorie, Leiden, Holland. A' ew synonymy.

1 etrany chus fransenni Oudemans, 1931, Ent. Her., 8(178): 227; Geijskes,
1939, Meded. Landbouwh. Wageningen, 42(4): 38. Types: female,
Wageningen, Holland, in greenhouse, on unnamed host; probably
in the Rijksmuseum van Natuurlijke llistorie, Leiden, Holland.
A ew synonymy.

7 etrany chus aspidistrae Oudemans, 1931, Ent. Her., 8(179): 258;
Geijskes, 1939, Meded. Landbouwh. Wageningen, 42(4): 39.

Types: male and female, Halfweg, Holland, on Aspidistra elatiae;
probably in the Rijksmuseum van Natuurlijke llistorie, Leiden,
Holland. New synonymy.

I etrany chus choisyae Oudemans, 1931, Ent. Her., 8(180): 274; Geijskes,
1939, Meded. Landbouwh. Wageningen, 42(4): 38. types: male,
female, and nymph, Apeldoorn, Holland, on Choisya temata ;
probably in the Rijksmuseum van Natuurlijke llistorie, Leiden,
Holland. New synonymy.

I etrany chus stellariae Oudemans, 1931, Ent. Her., 8(180): 275;
Geijskes, 1939, Meded. Landbouwh. Wageningen, 42(4): 39.

types: female and nymph, Arnhem, Holland, on Stellaria media ;
probably in the Rijksmuseum van Natuurlijke llistorie, Leiden,
Holland. New synonymy.

Tetranychus violae Oudemans, 1931, Ent. Her., 8(180): 277. Type:
one male, Naarden, Holland, on Viola tricolor, probably in the
Rijksmuseum van Natuurlijke llistorie, Leiden, Holland. New
synonymy.

7 etranychus manihotis Oudemans, 1931, Ent. Her., 8(181): 289. Types:
male, female, nymph, and larva, Berlin-Dahlem, Germany, on
Manihot utillissima ; probably in the Rijksmuseum van Natuurlijke
llistorie, Leiden, Holland. A ew synonymy.

440

Spider Mites

Eotetrany chus inexspectatus Andre, 1933, Bui. Mus. Natl. Hist. Nat.
Paris, 5: 131. Types : males and females, Paris, France, in
greenhouse, on Acalypha spp. and Salvia splendens ; probably
in the Museum d’llistoire Naturelle de Paris. New synonymy.

1 etranychus dahliae Oudemans, 1937, Krit. Hist. Overz. Acar., 3(C):
1022. Based on descriptions of specimens from Europe, on dahlia.
New synonymy.

Eotetranychus turhestani Ugarov and Nikolskii, 1937, Sredneaz. Stant.
Zasch. Rastenii, p. 28. Described from specimens from Tashkent,
Russia, on many hosts.

Tetranychus turkestani, Baker and Pritchard, 1953, Ililgardia, 22(7): 213.
Eotetranychus scabrisetus Ugarov and Nikolskii, 1937, Trudy Sredneaz.
Stan. Zashch. Rast., p. 33. Described from male and female
specimens from Tashkent, Russia, on grass. New synonymy.
Eotetranychus cucurbitacearum Sayed, 1946, Bui. Soc. Fouad ler Ent.,
30: 90. Types: males and females, Egypt, on weeds, shrubs,
and trees; probably in the collection of M. T. Sayed. New
synonymy.

Tetranychus multisetis McGregor, 1950, Amer. Midi. Nat., 44(2): 294;
Davis, 1952, Pan-Pac. Ent., 28: 1; Keh, 1952, Jour. Econ.
Ent., 45: 308. Types: males and females, Riverside, Cali¬
fornia, on bean; in the U. S. National Museum.

There is no doubt that the name Tetranychus telarius as employed
here represents a polytypic species represented by at least several
subspecies or species.

Differences have been noted from samples taken in many parts of
the world with regard to the comparative development of the inediodorsal
spur of the empodium as well as the length of the empodial digits on
leg I of the male and the comparative development of the empodial
spur, especially on leg II, but also legs III and IV of the male. There
is rarely some variance in the comparative length of the terminal sensil-
lum of the male palpus. The knob of the aedeagus is always small, but
its axis sometimes forms a small angle with the axis of the shaft; and
the dorsal margin of the knob as well as the development of each of its
angular projections varies considerably. In some cases (particularly
in Ceylon) the proximal pair of duplex setae on tarsus I is set more
proximally than usual. We have been unable to correlate these dif¬
ferences, even though some populations appear to be amply distinct
on a local basis.

Actively feeding females in the more temperate zones of each hemi¬
sphere are greenish in basic color, and typically with a large internal

7 flrunychivi telariua females: the green color form; (lie carmine color form; and ilx nonfeeding colmalton

•141

Subfamily l ctrany chinae llerlese

fig. 391. Tetranychus telarius : aedeagi.

dark., trifid spot on each side of t he body. Ibis form represents typical
telarius. In the tropics and often in northern greenhouses, the females
are carmine in basic color, typically with darker internal markings
along each side of the body. Most of the morphological differences
exhibited in specimens that vve have studied are in forms from the
tropics of subtropics, presumably carmine in color.

One of these carmine forms sometimes exhibits in the female two
(or one) sensory setae in addition to the four tactile setae that typically
are found proximal to the proximal duplex setae as in the male. Davis
(1952) showed that females with the extra setae breed freely with
carmine males lacking such, setae, the chaetotaxy of the offspring
resembling the mother. This morphological distinction is, therefore,
of no value for characterizing one of the carmine forms.

However, when Kell (1952) crossed the green form with the carmine
form, reproductive isolation was evident in most cases in which the
first generation was inbred; and subspecies or species rank was in¬
dicated for the two color forms used in his experiments.

Boudreaux (in litt.) has suggested that rearing experiments indicate
that the green form, T. telarius , is a distinct species, as is the red form,
T. cinnabarinus, with T. multisets (the red form with the extra tarsal I
setae) a subspecies or variety of T. cinnabarinus.

Tetranychus telarius (Linnaeus) has been accepted by the great
majority of acarologists as the scientific name of the common spinning
mite of Europe — the two-spotted spider mite of North America.

Linnaeus (1758) described Acarus telarius, the only tetranychid
among the 38 species of mites included in his tenth edition of “Systema
Naturae.” It is relevant that Linnaeus previously (1746) in his “Fauna
Suecica,” referred to two such mites: Acarus alceae and Acarus viridi-
albicans foliorum tiliae. Both of these concepts were united in the
1758 publication, inasmuch as Linnaeus referred to .4. telarius as being
a spinning mite on European plants, also found in greenhouses (“ caldario
inclusis ”) and on Tilia (linden).

442

Spider Mites

Twentieth century acarologists decided that Linnaeus included
two or three species in his description of Acarus telarius: 1) the common
outdoor spinning mite of Europe, 2) a species that is more or less
confined to the linden tree in Europe, and 3) a greenhouse species
closely allied to the common spinning mite.

Tragardh (1915), wdio might be considered the first modern reviser
(see Eotetranychus tiliarium) first made such a distinction obvious,
and he referred to the common outdoor mite as T etranychus telarius ,
the greenhouse form being T. altheae. Oudemans (1931) maintained
that telarius should be used for the linden mite, and he substituted
the name T. urticae for the common spinning mite indoors and outdoors.
Zacher (1916) followed Oudemans in restricting telarius to the linden
tree mite, but he used the specific name altheae for the common spinning
mite of Europe. Andre (1933) followed a combination of these ideas,
7. telarius being the linden mite, T. urticae the common spinning mite
outdoors, and T. ludeni being the greenhouse relative.

Hirst (1920, 1924) argued strongly that telarius should be retained
for the common spinning mite of Europe. And in North .America, Banks
and Ewing continued to apply this name to the similar species in this
country.

McGregor (1944) followed Zacher in restricting telarius to the linden
mite, and he employed the specific name altheae for the common spinning
mite of Europe. McGregor at that time considered altheae to be present
in North America; but he later (1950) restricted American specimens
to T etranychus bimaculatus, a name that has been used by economic
entomologists in this country during the past few years.

In most of the voluminous literature dealing with the common spinning
mite of Europe or the two-spotted spider mite, the name T etranychus
telarius has been used; and it is best to preserve this Linnaean name
for the common species.

It is true that an entirely different species is often found on linden
in Europe, but so is the common spinning mite. More recent European
workers who could definitely separate the two species have testified
to this, and we have seen linden defoliated by the two-spotted spider
mite in California.

The synonymy here included under the name 1 etranychus telarius
is undoubtedly subject to further scrutiny. Most of the synonymy of
older names is not new, and most of the names were proposed long ago
in Europe when the taxonomy of tetranychids was, indeed, little under¬
stood. No attempt has been made to include references to other than
names of zoological standing and references that may have a direct
(and usually modern) bearing on the interpretation of these names.

Subfamily I etranychinae Herlese

Undoubtedly, u careful, modern study of the tetrunychoid and allied
mites of Europe would enable new interpretations of some of the de¬
scriptions.

We have attempted to give reasonable interpretations to the European
descriptions, and we have believed it best in many cases to place a
name in synonymy with the common or two-spotted spider mite of Europe
rather than let the name dangle, perhaps forever, as a norneri dubium.

1 he first of such names is Acarus sarnbuci Schrank. It is probable
that modern acarologists were correct in considering this mite to be
an overwintering or else the carmine form of the two-spotted spider
mite; but it could also have represented some predaceous prostigmate.

Hirst (1920) maintained that a single male that he hud examined
representing Acarus linteari cus Dufour, 1832, from England on gorse,
was distinct with regard to the aedeagal termination from the two-spotted
spider mite. Oudemans (1931) did not agree with Hirst; and we have
studied two collections from England, on gorse, transmitted by courtesy
of A. M. Massee, that are indistinguishable from the tw’o-spotted mite.
/ etranychus lintearicus is, therefore, considered to be a synonym.

1 etranychus urticae Koch, the name commonly used in Europe and
British territories during recent years, undoubtedly represents the same
species. I. fervidus Koch probably represents the hibernating color
form of the same species. However, 7. vibumi Koch could be an
Eotetranychus.

Boisduval (1867) as well as Donnadieu (1875) introduced a number
of new names based primarily on color characters, host, and size. Most
of these names are considered to be based on variants, but 1 etranychus
rosarum might well represent an entirely different type of mite.

Murray (1877) had an unusual understanding of the tetranychid and
other mites at the time of his work, and 1 etranychus eriostemi, therefore,
must represent the two-spotted spider mite. 7. fici was regarded as
an imported species, and we are unable to evaluate this possibility;
the fig is known to be a host of the two-spotted spider mite.

T etranychus altheae von Hanstein (1901), was promulgated by
Tragardh (1915) as a name for the greenhouse two-spotted spider mite
as differentiated from the outdoor form in Europe. If 7. altheae had been
restricted to the carmine females, the differentiation would have been
more valid. However, Tragardh’s distinction has not been acceptable,
and 7. altheae , as far as the literature is concerned, is another name
used in the telarius complex.

During 1930-37, Oudemans described a number of new species of
7 etranychus from Europe, each based on differences of characters that
we are not able to appreciate: integumentary striae of the female solid

444

Spider Mites

or dotted (now known to be a seasonal character — see Pritchard and
Baker, 1952); width of the diamond-shaped figure formed by the striae
between the third pair of dorsocentral hysterosomals and the inner
sacrals; basic color of the female in life; and other variations such
as the number of chambers at the distal end of the peritreme, the de¬
velopment of the empodial spur on legs III and IV of the male, the
apparent length of the terminal sensillum on the palpus of the female,
and the comparative length of the dorsal propodosomals.

It is possible that Oudemans has validated names for several dif¬
ferent species, but this is not apparent from his descriptions nor from
the Oudemans drawings that were published by Geijskes. Consequently,
nearly all V>f these names are here considered to be synonyms. The
aedeagus of each species, when known to Oudemans, was simply re¬
ferred to as the hamate type, thus confirming only the generic placement.

There is no justification for the obvious belief of Oudemans that
the spider mites on introduced greenhouse plants were imported from
the native country of the plants.

Andre (1933) described as Eotetranychus inexspectatus a greenhouse
form (with greenish females) that he considered to be distinct by pos¬
sessing four pairs of proximoventral hairs on the empodium. Cotype
specimens kindly loaned by Dr. Andre are indistinguishable from the
tw'o-spotted spider mite. The aedeagus of inexspectatus as figured by
Andre has the terminal knob decidedly enlarged. The male loaned to
us for study was mounted with the aedeagus oriented dorsoventrally,
but it appeared to present no differences from the two-spotted spider
mite.

Reck (1950) considered turkestani to be a synonym of the common
spider mite of Europe. Scabrisetus is here considered also to be a
synonym; its aedeagus (figured only from a dorsal aspect) was described
as being similar to that of turkestani, although the peritreme was re¬
garded as being straight, not hooked distally.

The earliest trinomial for the carmine form appears to be T etranychus
telarius cinnabarinus Boisduval. Most of the older students, as well
as many modern workers, have referred to the orange, non-feeding phase
as “red” (hence, the name “red-spiders”), and the synonymy of this
form is difficult to determine. Our lack of knowledge of the outdoor
occurrence of the carmine form in Europe adds to the problem. Among
more recent names, however, T. cucurbitacearum Sayed (in part), T.
multisetis McGregor, and T. urticae dianthica Dosse are more certain
to represent this form. We have compared live material of carmine,
“resistant” mites from greenhouse carnations in England with similar
specimens in California.

Subfamily I etranychinae Herlese

Numerous collections ot tins species complex liuve been studied
from through out the United States and Hawaii, Europe, tbe Middle East,
South Africa, Peru, New Zealand, Western Australia, and Ceylon. Tbe
plant host list is exceedingly large.

Literature Cited

Andre, Marc

1932. Compte rendu d’unu mission dans le Sud-Algerien (May 1932)
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1932. Contribution a l’etude du “ilou-l' aroua” Tetranyque nuisible
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301-338.

1933. Note sur “l’Araignee rouge” des serres du Museum. Bui.
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1933. Sur la biologie des letranyques tisserands. Rev. Path.,
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1933. Note sur un Tetranyque nuisible au cottonier en Nouvelle-
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1934. Note de systematique sur des letranyques. Bui. Mus. Natl.
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1937. Util ite et Applications des Etudes Vcarologiques, 38 pp.
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1941. Sur le Bryobia praetiosa Koch (acarien). Bui. Mus. Natl.
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Bagdall, A. I.

1948.* Novii ved pautiknovo klescha ez Armenii. Uokl. Akad. Nauk
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Baker, Edward W. and G. W. Wharton

1952. An introduction to acarology, 465 pp. Macmillan Co., New
1 ork.

Baker, Edward W. and A. Earl Pritchard

1953. 1 lie family categories of tetranychoid mites, with a review
of the new families Linotetranidae and 1 uckerellidae. Ann.
Ent. Soc. Amer., 46(2): 243-258.

1953. A Guide to the spider mites of cotton. Hilgardia, 22(7):
203-234.

*t,e have not seen this article.

[447]

448

Spider Mites

Danks, Nathan

1894. Some new American Acarina. Trans. Amer. Ent. Soc., 21:
209-222.

1900. The red spiders of the United States {T etranychus and Stig-
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1904. Four new species of injurious mites. Jour. New York Ent.
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1905. Descriptions of some new mites. Proc. Ent. Soc. Wash.,
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1907. A catalogue of the Acarina, or mites, of the United States.
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Index of Host Plants

Abies , 328 Atriplex, 399

Acalypha, 440 Averrhoa, 335

Acer, 179, 183, 184, 187, 205, 213, avocado — see Persea

297, 300
Achras, 119
Adenostoma, 192
Aesculus , 179, 184, 212
Ageratum, 47
Agropyron, 52
Agrostis , 88 , 229 , 257
A l biz zia, 124
Alchimilla , 214
alder — see Alnus
alfalfa — see Medic ago
Allium, 55
almond — see Prunus
Alnus, 131, 183, 211
Althaea, 420, 438
Amelanchier, 187
Andropogon, 248
Anona, 330

antelope brush — see Purshia
Antirrhinum, 136
Apium, 404, 407 , 409
apple — see Malus
Arachis — 411, 420
arbor-vitae — see Thuja
Areca, 365

Artemisia, 56, 67, 210, 211
Arundo, 346
Asclepias , 390 , 408
ash — see Fraxinus
Asparagus , 64, 237, 238
aspen — see Populus
Aspidistra, 439
Astragalus, 32, 111

azalea — see Rhododendron

Balsamorrhiza, 69

bamboo, 249, 355, 417

Bamboranta, 409

banana — see Musa

barley — see Hordeum

basswood — see Tilia

Bauhinia, 420

beech — see Fagus

bean — see P haseolus

beet— see Beta

Bermuda grass — see Cynodon

Beta, 409

Betula, 183

Bikukulla, 30

Biota — see Thuja

birch — see Betula

blackberry— see Rubus

blackthorn — see Prunus

black locust — see Robinia

blueberry — see Vaccinium

Bouteloa, 346

boxwood — see Buxus

box-elder — see Acer

bramble — see Rubus

Brassica, 403, 404, 420

Buddleia, 420

bur-clover — see Medicago

Buxus, 31, 105, 109, 308

cabbage — see Brassica
Cajanus, 153

463

Index of Host Plants

California poppy — sit Eschscholzia

Calamagrostis , 260

Calluna, 17-1

Camellia, 308, 316

camphor-tree — see Cinnamomum

cantaloupe — see Cucumis

Carica, 360, 420

carob — see Ceratoniu

Carpinus, 179, 181, 183

carrot — see Daucus

Carya, 211, 212, 311, 392

cassava — see Manihot

Cassia, 118, 123, 153, 269

Castanea, 2 1 2 , 301, 302

castor-bean — see Ricinus

Ceanothus , 206 , 390

celery — see Apium

Celtis , 417

Cenchrus, 346

Ceratonia, 342

Cercocarpus , 177, 178, 208

Chamaecyparis , 327

Chenopodium, 390

cherry — see Prunus

chestnut — see Castanea

China-berry — see Melia

Chloris, 346

Choisya, 133, 439

Chrysanthemum, 26

Cinnamomum, 205, 230, 335

Cinchona, 420

Citrullus , 358, 420

Citrus, 118, 123, 133, 199 , 202 , 20 5,
206, 266, 267, 411, 412
Clitoria, 431
clover — see Trifolium
Codaeum, 123, 420
Coffea, 315, 335
coffee — see Coffea
Combretum, 371
Convolvulus , 390, 407
corn — see Zea
Corylus, 35, 179, 183
Cosmos, 407
Cotoneaster , 132, 390
cotton — see Gossypium
cottonwood — see Populus
Covillea — see Larrea
Cracca, 420
Crataegus , 179, 384
creosote bush — see Larrea
croton — see Codaeum
Cryptomeria, 284
cucumber — see Cucumis
Cucumis, 55, 390, 404, 425, 437
Cucurbita, 405, 420, 427

Cupressus, 157, 159, 293, 297, 327
Cyclamen, 437
Cynoches , 420

Cynodun, 88 , 92, 229 , 232 , 251, 253,
257, 345, 346, 353
cypress — see Cupressus
Cytisus, 20

Dahlia, 440

Dalbergia , 148

date — see Phoenix

Datura, 406

Daucus, 55

Dendrobium, 357

Derris , 339

Digitariu, 346

Distichlis, 86, 88, 229, 232

Drac aena, 437

Echinochloa, 346
eggplant — see Solanum
Eichhornia, 408, 420
Elaeocarpus , 242, 246
Elae agnus , 133, 205
elm — see Ulmus
Elymus, 254
Ephedra, 73
Epicampes , 254
Eragrostis , 346
Erigeron, 404
Eriobotrya, 364
Eriodictyon, 404
Eriostemon, 438
Eryngium, 73
Erythrina, 148, 149
Eschscholzia, 390
Eugenia, 316, 330
Euphora, 335
Euphorbia, 438

Fagus, 211, 212, 213

Ficus, 123, 137, 200

fig — see Ficus

Flacourtia, 123

foxtail millet — see Setaria

Fragaria, 401, 424, 425, 427, 439

frangipani — see Plumeria

Fraxinus , 214, 392

Garry a, 390
Gladiolus , 55 , 404
Gleditsia, 100, 163, 165, 167
gooseberry — see Ribes
Gossypium, 55, 342, 358, 359, 360,
390, 393, 404, 405, 408, 409, 430
Grammatophyllum, 420

464

Spider Mites

grape — see V it is

grass, 26, 28, 32, 55, 58, 77, 90, 92,
115, 134, 138, 267, 269, 354
Grossularia, 28

hackberry — see Celtis
Hakea, 225

hawthorn — see Crataegus
hazel — see Corylus
Hedera, 31, 32
Helianthus , 390 , 404
Hemizonia, 70, 390
Hibiscus , 409
hickory — see Carya
holly — see Ilex
hollyhock — see Althaea
honey locust — see Gleditsia
Hordeum, 32, 52, 55, 347
hornbeam — see Carpinus
horse-chestnut — see Aesculus
horseweed — see Erigeron
Hydrangea, 427

Ichthyomethia, 148
Ilex, 305, 308

incense cedar — see Libocedrus

Ipomaea, 409, 420

Iris, 55

Iseilema, 358

ivy — see Hedera

Jamaica dogwood - see Ichthyomethia

Johnson grass — see Sorghum
Juglans, 32, 132, 390, 425
J ungia — see Salvia
juniper — see Juniperus
] uniperus , 83, 110, 159, 162, 318, 327,
328

khadhrawi, 349

Kochia, 56

kudzu — see Pueraria

Lactuca, 55
Lantana, 406
Larrea, 19, 20, 403, 404
laurel — see Laurus
Laurus, 308

Lebbek-tree — see Albizzia

legume, 51, 221

lemon — see Citrus

Leonotis, 408

lettuce — see Lactuca

Libocedrus, 110, 154, 157, 322, 327

Ligustrum, 429

linden — see Tilia

Liriodendron, 413
Litchi, 335, 365
locust — see Robinia
loquat — see Eriobotrya
Luffa, 420
Lupinus, 47, 48
Lycopersicum, 404, 420

Maclura, 395
Magnolia, 412, 413
maidencane grass — see Panicum
maize — see Zea

Malus, 31, 32, 55, 132, 179, 183, 384,
385, 388, 392, 393, 394, 395, 401, 425
Malva, 192
Malvastrum, 192
Mangifera, 316, 330, 335, 420
mango — see Mangifera
Manihot, 147, 148, 360, 439
maple — see Acer
Maranta, 409, 420, 427
Maris cus , 94

Medicago, 28, 32, 55, 111, 206, 390,
404, 425, 431
Melaleuca, 315, 316
Melanolepis , 430
Melia, 420
melon — see Cucumis
Mentha, 438

milkweed — see Asclepias

Mimulus , 404

mint — see Mentha

monkey-flower — see Mimulus

morning-glory — see Convolvulus

Morus, 200 , 269, 341, 431, 438

mountain ash — see Sorbus

mountain mahogany — see Cercocarpus

mulberry — see Morus

Musa, 138

Myrthe — see Myrtus

Myrtus , 340

nectarine — see Prunus
nettle — see Urtica
nightshade — see Solanum

oak — see Quercjis
okra — see Hibiscus
Olea, 206
olive — see Olea
Oncoba, 123
onion — see Allium
Opuntia, 403, 404
orange — see Citrus
orchid, 32
Oryza, 357

Index of Host Plants

Osage orange — see Maclura
Oxalis , 45, 61

paddy — see Oryzu
palm, 409
almetto — see Sabal
anicum, 346, 353
papaya — see Carica
para grass — see Panicum
Parietaria, 33
parsley — see P etroselinum
Parthenocissus , 316
Pass i flora, 173, 429, 430
passion flower — see P assiflora
pea — see Pisum
peach — see Prunus
peanut — see Arachis
pear — see Pyrus
pecan — see Carya
Persea, 203, 332, 333, 335, 336
P etroselinum, 425
Petunia, 47
P hacelia, 403

Phaseolus, 360 , 390 , 393, 409 , 420,
425, 427, 440
Philadelphicus , 388
Phleum, 349

Phoenix, 349, 350, 352, 353
Photinia, 305
P hyllostachys , 251
pigweed — see Chenopodium
Picea, 289, 319, 322, 325, 327, 328
pine — see Pinus

Pinus, 19, 280, 281, 282, 284, 287, 289,
291, 322, 325
Pisum, 51, 409
plane tree — see Platanus
P latanus , 304, 305, 341
plum — see Prunus
Plumeria, 118
P oinsettia, 427
pomegranate — see Punica
poplar — see Populus
Populus, 189, 191, 353, 395
P otentilla, 131
Primulus , 339
privet — see Ligustrum
prune — see Prunus

Prunus, 31, 32, 34, 118, 123, 132, 134,
177, 179, 183, 186, 335, 384, 385,
388, 393, 425, 437
Pterorarya, 181
Puereria, 153 , 406
Punica, 335
Purshia, 177, 178, 187
P yracantha, 132, 305

Pyrus, 32, 131, 132, 134, 183, 312,
384, 385, 403, 425

Quercus, 187, 212, 213, 269, 301, 302,
305, 308, 310, 365,366, 368, 369,
372, 385
Quisqualis , 316

raspberry — see Rubus
redwood — see Sequoia
reedgrass — see Calamagrostis
Re inwardtia, 439
Rhurnnus , 32, 174
Rhododendron, 172, 173, 205, 308
Ribes , 3 1, 131, 388
rice — see Oryza

Ricinus, 115, 123, 134, 206, 406, 408,
437

Robinia, 100, 132, 223, 224, 390, 393
Rosa, 134, 194, 196, 199, 200, 330,
364, 365, 395, 417, 437
rose — see Rosa
royal palm — see Roystonea
Roystonea, 414, 417
Rubus , 32, 173, 183, 194, 196, 200, 214,
218, 219, 305, 386, 388, 393, 417
rye — see Secale

Sabal, 169

Saccharum, 249, 347, 348, 353, 354,
355, 356

Saint Augustine grass — see
Stenotaphrum

Salix, 175, 177, 179, 183, 189, 191,
234 , 236 , 240, 242, 335, 342
Salsola 55 -

salt grass — see Distichlis
Salvia, 32, 213, 390, 405, 406, 440
Sambucus , 435
sapota — see Achras
Sarothamnus vulgaris, 20
Secale, 347
Sequoia, 327

service berry — see Amelanchier
Setaria, 346, 357
Sida, 41

smut grass — see Sporobolus

snow berry — see Symphoricarpos

Solanum, 405, 409, 425, 430

Sorbus, 132

Sorghum, 55, 346, 354

Soya, 153

Sphaeralcea, 39

Spiraea, 35, 179, 183, 248

spirea — see Spiraea

Sporobolus , 346, 354

466

Spider Mites

spruce — see Picea
squash — see Cucurbita
Stellaria, 439
Stenotaphrum, 81
Stillingia, 404
Stizolobium, 115, 123
strawberry — see Fragaria
sugarcane — see Saccharum
sunflower — see Helianthus
sweet potato — see Ipomoea
sycamore — see Platanus
Symphoricarpos , 206 , 208

Talisia, 205
tangerine— see Citrus
tarweed — see Hemizonia
Taxodium, 297
tea — see Thea
Terminalia, 316
Thea, 315, 316

Thuja, 110, 157, 159, 162, 321, 327,
328

Tilia, 30, 113, 115, 178, 179, 395, 432

timothy — see Phleum

tomato — see Lycopersicum

toyon — see Photinia

Trifolium, 31, 32, 47, 49, 51, 390, 425

Triticum, 19, 32, 52, 55, 353

Triumfetta, 430

tulip-tree — see Liriodendron

turnip — see Brassica

Ulex, 436

Ulmus, 34, 128, 132, 214, 390, 393,
395, 417, 438
Umbellularia, 134
umbrella tree — see Melia
Urtica, 22, 437

Vaccinium, 179, 183, 232

velvet bean — see Stizolobium

vetch — see Vicia

Viburnum, 437

Vicia, 51, 388, 390

Viola, 427, 439

violet — see Viola

Virginia creeper — see Parthenocissus
Vitis, 186, 215, 316, 330, 335, 342,
390, 437

walnut — see Juglans
water-hyacinth — see Eichhornia
watermelon — see Citrullus
Wedelia, 430
wheat — see Triticum
willow — see Salix

Xylosma, 133

Zea, 342, 345, 354, 355, 358
Zinnia elegans, 31
Zizyphus , 97, 118, 123

Index of Spider Mites

Italics are used to indicate names in synonmy, misidentifications, and erroneous
combinations.

Acarus aceris, 297

Acarus cinnabarinus , 437

Acarus coffeae, 315

Acarus cucumeris , 437

Acarus denticulatus , 15

Acarus ferrugineus , 437

Acarus graminum, 26

/Icarus haematodes , 437

Acarus latens, 51

Acarus petrarum, 52

Acarus prae gnans , 52

Acarus rosarum, 437

/Icarus sambuci, 435

Acarus telarius, 432

Acarus textor, 436

Acarus vitis, 437

Allonychus, 137

Allonychus braziliensis, 137

Amphitetranychus , 374

Amphitetranychus salicicola, 189

Amphitetranychus viennensis, 384

Anatetranychus , 215

Anatetranychus hakea, 225

Anychus , 111

Anychus africanus , 118

Anychus banksi, 115

Anychus clarki, 118

Anychus latus , 118, 123

Anychus orientalis , 118

Anychus ricini, 118

Anychus rusti, 118

Anychus verganii, 118

Aplonobia, 58
Aplonobia acharis, 69
Aplonobia anisa, 64
Aplonobia calame, 70
Aplonobia deina, 67
Aplonobia histricina, 59
Aplonobia myops, 63
Aplonobia oxalis, 61
Apotetranychus , 138
Apotetranychus georgicus, 174
Apotetranychus longipenis, 384
Apotetranychus muscicola, 174
Apotetranychus virginis, 385

Brevipalpus, 5
Bryobia, 14
Brvobia amygdali, 32
Bryobia bakeri, 19
Bryobia borealis, 24
Bryobia brevicornis , 28
Bryobia cristata, 22
Bryobia curiosa, 19
Bryobia denticulala, 26
Bryobia drummondi, 19
Bryobia glacialis , 28
Bryobia gloriosa, 28
Bryobia goriensis, 32
Bryobia graminum, 26
Bryobia haustor, 28
Bryobia humeralis , 30
Bryobia longicornis , 30
Bryobia longisetis, 32

14671

468

Spider Mites

Bryobia nobilis , 28
Bryobia osterloffi, 32
Bryobia pallida, 28
Bryobia parietariae, 33
Bryobia praetiosa, 22, 26
Bryobia pratens is , 28
Bryobia redikorzevi, 34
Bryobia ribis, 28
Bryobia sarothamni, 20
Bryobia speciosa, 28
Bryobia ulmophila, 34
Bryobia urticae, 22
Bryobia weyerensis, 28
BRYOBIINAE, 12
BRYOBIINI, 14

Distigmatus , 374
Distigmatus pilosus, 437
Divarinychus , 225
Divarinychus floridensis , 237

Epitetranychus , 374
Epitetranychus aequans, 438
Epitetranychus alceae, 438
Epitetranychus altheae, 438
Epitetranychus asparagi, 237
Epitetranychus caldari.i, 439
Epitetranychus fagi, 212
Epitetranychus hamatus , 438
Epitetranychus reinwardtiae , 439
Epitetranychus sambuci, 436
Eotetranychus, 138
Eotetranychus aceri, 213
Eotetranychus aesculi, 184
Eotetranychus aurantii, 213
Eotetranychus bakuriensis, 214
Eotetranychus caribbeanae, 147
Eotetranychus carpini, 179
Eotetranychus carpini borealis, 179
Eotetranychus clitus, 170
Eotetranychus coryli, 183
Eotetranychus cucurbitacearum, 440
Eotetranychus deflexus, 206
Eotetranychus ecclisis, 210
Eotetranychus fagi, 212
Eotetranychus fraxini, 214
Eotetranychus frosti, 199
Eotetranychus georgicus, 174
Eotetranychus gibbosus, 162
Eotetranychus hicoriae, 211
Eotetranychus hirsti, 200
Eotetranychus inexspectatus , 440
Eotetranychus jungiae, 213
Eotetranychus lewisi, 205
Eotetranychus libocedri, 154
Eotetranychus malvastris, 192

Eotetranychus multidigituli, 163
Eotetranychus muscicola, 174
Eotetranychus pallidus, 211
Eotetranychus perplexus, 175
Eotetranychus planki, 148
Eotetranychus populi, 189
Eotetranychus pruni, 186
Eotetranychus rubiphilus, 214
Eotetranychus scabrisetus , 440
Eotetranychus sexmaculatus, 202
Eotetranychus smithi, 192
Eotetranychus steganus, 167
Eotetranychus suginamensis, 200
Eotetranychus talisiae, 205
Eotetranychus telarius, 178
Eotetranychus thujae, 159
Eotetranychus tiliarium, 178
Eotetranychus turkestani , 440
Eotetranychus ulmicola, 314
Eotetranychus uncatus, 183
Eotetranychus viticola, 186
Eotetranychus weldoni, 191
Eotetranychus willamettei, 187
Eotetranychus yumensis, 199
EURYTETRANYCHINI, 100
Eurytetranychus, 101
Eurytetranychus admes, 110
Eurytetranychus buxi, 103
Eurytetranychus latus, 105
Eurytetranychus recki, 111
Eurytetranychus stenoperitematus, 358
Eurytetranychus thujae, 110
Eurytetrany choides , 101
Eurytetranychoides thujae, 110
Eutetranychus, 111
Eutetranychus banksi, 115
Eutetranychus clarki, 118
Eutetranychus latus, 105
Eutetranychus mexicanus, 118
Eutetranychus pantopus, 123
Eutetranychus rusti, 118
Eutetranychus schultzi, 115
Eutetranychus spinosus, 113

Heteronychus, 5
Heteronychus brevipodus, 372
Hystrichonychus, 37
Hystrichonychus gracilipes, 39
Hystrichonychus sidae, 40

Mesotetranvchus, 73
Mesotetranychus samgoriensis, 73
Mesotetranychus vachustii, 73
Metatetranychus, 127
Metatetranychus alboguttatus , 131
Metatetranychus alni, 131

469

Index of Spider Miles

Metetetranychus cunestrinii, 131
Metatetranychus ritri, 133
Metatetranychus hadzhibejliae, 137
Metatetranychus mali, 131
Metatetranychus mus corum, 131
Metatetranychua pilosus, 131
Metatetranychua potentillae , 131
Metatetranychus spinigerus, 136
Metatetranychua ulmi, 128
Monoceronychus, 92
Monoceronychus aechmetes, 86
Monoceronychus californicus, 83
Monoceronychus corynetes, 75
Monoceronychus enoplus, 90
Monoceronychus linki, 92
Monoceronychus machetes, 81
Monoceronychus mcgregori, 77
Monoceronychus scolus, 90

Neobryobia, 44
Neobryobia spectabilis , 45
Neophyllobius, 5
Neophyllobius harti, 45
Neophyllobius horridus, 35
Neotetranychus, 215
Neotetranychus buxi, 105
Neotetranychus hakea, 225
Neotetranychus rubi, 218
Neotetranychus siccus, 219
Neotetranychus uniunguis , 322
Neotetranychus virginiensis, 223
Neotetranychus (Eutetranychus), 111
Neotetranychus (Eutetranychus) banksi,
115

Neotetranychus (Eutetranychus) spin-
os a, 113

Neotetranycops is , 37

Oligonychus, 270
Oligonychus aceris, 297
Oligonychus afrasiaticus, 349
Oligonychus alni, 131
01 igonvchus americanus , 322
Oligonychus bicolor, 308
Oligonychus bihariensis, 364
Oligonychus boudreauxi, 291
Oligonychus brevipilosus, 288
Oligonychus brevipodus, 372
Oligonychus coffeae, 315
Oligonychus coniferarum, 328
Oligonychus cunliffei, 284
Oligonychus endytus, 301
Oligonychus exsiccator, 347
Oligonychus gossypii, 359
Oligonychus gramineus, 347
Oligonychus hadrus, 369

Oligonychus hondoensis, 284
Oligonychus ilicis, 305
Oligonychus indicus, 354
Oligonychus inouei, 328
Oligonychus insularis, 330
Oligonychus iseilemae, 358
Oligonychus kobachidzei, 341
Oligonychus major, 332
Oligonychus mangiferus, 330
Oligonychus mcgregori, 359
Oligonychus rneritiei, 315
Oligonychus milleri, 280
Oligonychus minimus, 373
Oligonychus modestus, 355
Oligonychus mori, 341
Oligonychus mus corum, 131
Oligonychus newcomeri, 312
Oligonychus nuptialis, 340
Oligonychus oryzae, 357
Oligonychus parva, 341
Oligonychus perditus, 316
Oligonychus peronis, 336
Oligonychus peruvianus, 342
Oligonychus picei, 289
Oligonychus pityinus, 290
Oligonychus platani, 304
Oligonychus potentillae , 131
Oligonychus pratensis, 349
Oligonychus primulae, 339
Oligonychus pritchardi, 365
Oligonychus propetes, 366
Oligonychus punicae, 335
Oligonychus quercinus , 372
Oligonychus sacchari, 355
Oligonychus simplex, 349
Oligonychus stenoperitrematus, 358
Oligonychus stickneyi, 344
Oligonychus subnudus, 281
Oligonychus terminalis, 316
Oligonychus ulmi, 128
Oligonychus ununguis, 319
Oligonychus viridis, 311

Panonychus , 271
P anonychus mori, 341
Parotetranychus, 271
Paratetranychus afrasiaticus, 349
P aratetranychus alpinus, 322
Paratetranychus americanus , 322
P aratetranychus bicolor, 308
Paratetranychus bihariensis, 364
Paratetranychus bioculatus , 315
Paratetranychus brevipilosus, 288
P aratetranychus citri, 133
P aratetranychus coiti, 335
P aratetranychus hawaiiensis , 364
P aratetranychus coniferarum, 328

470

Spider Mites

P aratetranychus gossypii, 359
Paratetranychus heteronychus , 352
P aratetranychus hondoensis, 284
P aratetranychus ilicis, 305
Paratetranychus indicus, 354
P aratetranychus inouei, 328
Paratetranychus insularis, 330
Paratetranychus kobachidzei, 341
P aratetranychus mangiferus, 330
P aratetranychus mcgregori, 359
P aratetranychus mexicanus , 354
P aratetranychus milleri, 280
P aratetranychus modestus, 355
Paratetranychus mytilaspidis , 133
P aratetranychus newcomeri, 312
P aratetranychus nuptialis, 340
Paratetranychus oryzae, 357, 358
Paratetranychus peruvianus, 342
P aratetranychus pilosus, 131
Paratetranychus pilosus alboguttatus , 131
P aratetranychus pilosus occidentalis, 131
P aratetranychus pini, 322
P aratetranychus platani, 304
P aratetranychus pratensis, 349
Paratetranychus primulae, 339
P aratetranychus pritchardi, 365
P aratetranychus punicae, 335
P aratetranychus sacchari, 355
P aratetranychus simplex, 349, 350
Paratetranychus stenoperitrematus, 358
Paratetranychus stickneyi, 344, 347
P aratetranychus subnudus, 281
Paratetranychus terminalis, 316
P aratetranychus trinitatis , 342
P aratetranychus ulmi, 129
P aratetranychus uniunguis , 322
P aratetranychus ununguis, 319
Paratetranychus viridis, 307
P aratetranychus yothersi, 330
P eritetranychus , 225
P eritetranyci.us glabrisetus, 269
P eritetranychus tuberculatus, 269
Petrobia, 42
Petrobia apicalis, 49
Petrobia brevipes, 56
Petrobia cephae, 55
Petrobia erevanica, 56
Petrobia harti, 45
Petrobia latens, 51
Petrobia lupini, 47
Petrobia zachvatkini, 56
PETROBIINI, 42
Phytoptipalpus, 5
P latytetranychus , 138
Platytetranychus gibbosus, 163

Pseudobryobia, 15
Pseudoleptus, 5

Raoliella, 5

Rhyncolophus liaustor, 28

Sannio, 15
Schizonobia, 56
Schizonobia sycophanta, 58
Schizotetranychus, 225
Schizotetranychus andropogoni, 248
Schizotetranychus asparagi, 237
Schizotetranychus camur, 260
Schizotetranychus celarius, 249
S c hizotetranychus cercocarpi , 208
Schizotetranychus cornus, 242
Schizotetranychus elymus, 254
Schizotetranychus eremophilus, 251
Schizotetranychus floridens is , 237
Schizotetranychus fluvialis, 254
Schizotetranychus garmani, 233
Schizotetranychus cynodonis, 229
Schizotetranychus glabrisetus, 269
Schizotetranychus graminicola, 267
Schizotetranychus guatamalae-novae,
269

Schizotetranychus hindustanicus, 266
Schizotetranychus ibericus, 269
Schizotetranychus latitarsus , 249
Schizotetranychus nugax, 264
Schizotetranychus oudemansi, 232
Schizotetranychus parasemus, 230
Schizotetranychus schizopus , 232, 233
Schizotetranychus schizopus, 240
Schizotetranychus spireafolia, 248
Schizotetranychus tuberculatus, 269
Schizotetranychus viburni, 437
Schizotetranychus (Eotetranychus)
aceri, 213

Schizotetranychus (Eotetranychus)
aesculi, 184

Schizotetranychus (Eotetranychus)
bakuriensis, 214

Schizotetranychus (Eotetranychus)
carpinula, 181

Schizotetranychus (Eotetranychus)
coryli, 183

Schizotetranychus (Eotetranychus)
fagi, 212

Schizotetranychus (Eotetranychus)
fraxini, 214

Schizotetranychus (Eotetranychus)
pruni, 186

Schizotetranychus (Eotetranychus)
pterocaryae , 181

Schizotetranychus (Eotetranychus)
rubiphilus, 214

471

Index of Spider \lites

Schizotetranychus (Eotetranychus)

salictcola, 189

Schi zotetranychus (Eotetranychus)
ulmicola, 214

Schizotetranychus (Eotetranychus)
viticola, 186
Schmiedleinia, 15
Schmiedleinia tiliae, 30
Septanychus , 374
Septanychus urge minus , 403
Septanychus braziliensis, 138
Septanychus canadensis, 393
Septanychus cocosi, 414
Septanychus deserticola, 403
Septanychus deviatarsus , 406
Septanychus mexicanus, 411
Septanychus quinquenychus , 408
Septanychus schoenei, 392
Septanychus texazona, 403
Septanychus tumidus , 137
Septanychus tumidus, 408
Simplinychus , 101
Sirnplinychus buxi, 105
Stigmaeopsis, 225
Stigmaeops is celarius, 249

Tacebia, 271
Tacebia parva, 341
Tegopalpus, 5
Tenuicrus , 44
Tenuicrus errabundus , 45
TEN HIP AL POIDINI, 97
Tenuipalpoides, 97
Tenuipalpoides dorychaeta, 99
Tenuipalpoides zizyphus, 97
Tenuipalpus, 5
Te tranobia, 43
Tetranobia decepta, 52
TETR ANYCHIDAE, 4
T etr any china, 43
Tetranychina agerati, 47
Tetranychina apicalis, 49
Tetranychina harti, 45
Tetranychina lupini, 47
Tetranychina macdonoughi , 45
Tetranychina tritici, 52
Tetranychina tuberculata, 45
TETR AN YC HO IDE A, 5
Tetranychopsis , 34
Tetranychopsis histricina, 59
Tetranychopsis horridus, 35
Tetranychopsis paupera, 52
Tetranychopsis simplex, 52
Tetranychopsis spinosa, 113
Tetranycopsis, 34
Tetranvcopsis horridus, 34

letranycopsis spiraeae, 35
TETR ANYCH1NAE, 96
TETR ANYCH1NI, 124
Tetranychus, 373
Tetrany chus aceris, 299
Tetranychus ultheae, 438
l etranychus anuuniensis , 52
Ietranychus antillarurn, 408
Ietranychus aspidistrae, 439
Ietranychus atlanticus, 424
Ietranychus aurantii, 213
Ietranychus banksi, 115
Ietranychus bicolor, 308
Tetranyc-hus bimaculatus , 438
Tetrany chus bioculutus , 315
Tetrany chus borealis, 179
Tetrany chus californicus , 191
Ietranychus canadensis, 393
Tetrany chus caribbeanae, 147
Tetranychus carpini, 179
Tetrany chus caudatus, 375
Tetranychus celer, 375
Tetranychus choisyae, 439
Tetranychus citri, 133
Tetranychus cocosi, 414
Tetranychus cocosinus, 417
Tetranychus crataegi, 384
Tetranychus cristatus, 22
Tetranychus cucumeris , 437
Tetranychus cucurbitae, 419
Tetranychus dahliae, 440
Tetranychus deflexus, 206
Tetranychus desertorum, 403
Tetranychus dugesii, 431
Tetranychus ellipticus, 165
Tetranychus equatorius , 420
Tetranychus eriostemi , 438
Tetranychus exsiccator, 347
Tetranychus ferrugineus , 437
Tetranychus fervidus, 437
Tetranychus fici, 200
Tetranychus fici, 438
Tetranychus fijiensis, 382
Tetranychus flatus, 179
Tetranychus fragariae, 439
Tetranychus fransenni , 439
Tetranychus frosti, 199
Tetranychus gibbosus, 162
Tetranychus gigas, 405
Tetranychus glabrum, 375
Tetranychus gloveri, 408
Tetranychus gracilipes, 39
Tetranychus guatamalae-novae, 269
Tetranychus hicoriae, 211
Tetranychus homorus, 390
Tetranychus horridus, 34

472

Spider Mites

Tetranychus hydrangeae, 425
Tetranychus ilicis, 305
Tetranychus inaequalis , 438
Tetranychus kanzawai, 431
Tetranychus Iambi, 399
Tetranychus latus, 103
Tetranychus lewisi, 205
Tetranychus libocedri, 154
Tetranychus liniearicus , 436
Tetranychus longipes, 52
Tetranychus longipes, 375
Tetranychus longirostris, 376
Tetranychus longitarsus , 438
Tetranychus ludeni, 405
Tetranychus magnoliae, 412
Tetranychus major, 437
Tetranychus major, 375
Tetranychus malvastris, 192, 199
Tetranychus marianae, 429
Tetranychus manihotis , 439
Tetranychus mcdanieli, 386
Tetranychus merganser, 429
Tetranychus mexicanus, 411
Tetranychus minimus, 178
Tetranychus minor, 438
Tetranychus modestus, 355
Tetranychus molestissimus, 376
Tetranychus monticolus , 179
Tetranychus mori, 200
Tetranychus multidigituli, 163
Tetranychus multisetis , 440
Tetranychus mytilaspidis , 131, 133
Tetranychus neocalidonicus, 430
Tetranychus opuntiae, 403
Tetranychus oregonensis , 179
Tetranychus pacificus, 388
Tetranychus pallidus, 211
Tetranychus pantopus, 123
Tetranychus perplexus, 175
Tetranychus peruvianus, 342
Tetranychus picei, 289
Tetranychus piercei, 431
Tetranychus piger, 437
Tetranychus pilosus , 129
Tetranychus planki, 148
Tetranychus plumistoma, 438
Tetranychus polys, 396
Tetranychus populi, 189
Tetranychus pratensis, 349
Tetranychus pruni, 186
Tetranychus prunicolor, 375
Tetranychus quercinus , 213
Tetranychus quinquenychus , 408
Tetranychus reinwardtiae , 439
Tetranychus rosarum, 437
Tetranychus russeolus , 437
Tetranychus rusti, 116

Tetranychus salicicola, 189
Tetranychus salicis, 375
Tetranychus salviae, 406
Tetranychus sambuci, 435
Tetranychus schizopus, 240
Tetranychus schoenei, 392
Tetranychus sexmaculatus, 202
Tetranychus simplex, 349
Tetranychus spinigerus, 136
Tetranychus stellariae, 439
Tetranychus superba, 376
Tetranychus suginamensis, 200
Tetranychus talisiae, 205
Tetranychus taxi, 376
Tetranychus telarius, 178
Tetranychus telarius, 432
Tetranychus textor, 436
Tetranychus telarius haematodes , 437
Tetranychus thermophilus , 403
Tetranychus thujae, 159
Tetranychus tiliarium, 178
Tetranychus tini, 375
Tetranychus tlalsahuate, 376
Tetranychus trombidinus, 375
Tetranychus tumidellus, 409
Tetranychus tumidus, 408
Tetranychus ulmi, 128
Tetranychus uniunguis , 321
Tetranychus ununguis, 319
Tetranychus urticae, 436
Tetranychus urticae dia-ithica, 437
Tetranychus vestitus, 376
Tetranychus viburni, 437
Tetranychus viennensis, 384
Tetranychus violae , 439
Tetranychus virginis, 385
Tetranychus viridis, 307
Tetranychus vitis , 437
Tetranychus willamettei , 181
Tetranychus willamettei, 187
Tetranychus yothersi, 330
Tetranychus (Epitetranychus), 374
Tetranvchus ( Epitetranychus ) caldarii,
439 '

Tetranychus ( Epitetranychus ) ludeni,
406

Tetranychus ( Epitetranychus )
viennensis, 384

Tetranychus (Schizotetranychus)
andropogoni, 248
Tetranychus (Schizotetranychus)
hindustanic.us, 266
Torynophora, 15
Torynophora serrata, 28
Trombidium lapidum, 52
Trombidium tiliarium, 178
Tuckerella, 5