Life Sciences Miscellaneous Publications Royal Ontario Museum A Systematic Study of the Nearctic Larvae of the Hydropsyche morosa Group (Trichoptera: Hydropsychidae) Digitized by the Internet Archive in 2012 with funding from Royal Ontario Museum http://archive.org/details/systematicstudyoOOsche A Systematic Study of the Nearctic Larvae of the Hydropsyche morosa Group (Trichoptera: Hydropsychidae) A Systematic Study of the Nearctic Larvae of the Hydropsyche morosa Group (Trichoptera: Hydropsychidae) Patricia W. Schefter and Glenn B. Wiggins ROM A Life Sciences Miscellaneous Publication of the Royal Ontario Museum, Toronto ROYAL ONTARIO MUSEUM PUBLICATIONS IN LIFE SCIENCES The Royal Ontario Museum publishes three series in the Life Sciences: Contributions: a numbered series of original scientific publications. Occasional Papers: a numbered series of original scientific publications, primarily short and of taxonomic significance. Miscellaneous Publications: an unnumbered series on a variety of subjects. All manuscripts considered for publication are subject to the scrutiny and editorial policies of the Life Sciences Editorial Board, and to independent refereeing by two or more persons, other than Museum staff, who are authorities in the particular field involved. LIFE SCIENCES EDITORIAL BOARD Senior Editor: J. Barlow External Editor: C. S. Churcher Editor: J. L. Eger Manuscript Editor: C. S. Churcher Editor: E. J. Crossman Production Editor: B. E. Ibronyi Patricia W. Schefter is a Curatorial Assistant in the Department of Entomology, Royal Ontario Museum. Glenn B. Wiggins is Curator in charge. Department of Entomology, Royal Ontario Museum, and Professor in the Department of Zoology, University of Toronto. Cover: Hydropsyche morosa Hagen, final instar larva. Drawing by Anker Odum. Canadian Cataloguing in Publication Data Schefter, Patricia W., 1940- A systematic study of the Nearctic larvae of the Hydropsyche morosa group (Trichoptera : Hydropsychidae) (Life sciences miscellaneous publications, ISSN 0082-5093) Bibliography: p. ISBN 0-88854-321-2 I. Caddis-flies — Identification. I. Wiggins, Glenn B. II. Royal Ontario Museum. III. Title. IV. Series. QL518.H94S33 1986 595.7'45 C86-093039-4 Publication date: 15 July 1986 ISBN 0-88854-321-2 ISSN 0082-5093 (r)The Royal Ontario Museum, 1986 100 Queen's Park, Toronto, Canada, M5S 2C6 PRINTED AND BOUND IN CANADA AT THE ALGER PR1 SS CONTENTS Abstract 1 Introduction 1 The Hydropsyche morosa Group 2 Systematica 2 Biolog) 6 Range 7 Materials 7 Techniques 8 Chaetotaxal Characters 9 Introduction 9 Morphology 10 Primary Setae 10 Secondary Setae 1 1 Distribution 17 Other Characters 2 1 Key to Nearctic Larvae of the Hxdropsxche morosa Group 22 Diagnosis and Discussion for Species 44 Hxdropsxche aenigma Schefter, Wiggins, and Unzicker 44 Hxdropsxche alhedra Ross 45 Hxdropsxche alternans (Walker) 48 Hxdropsxche amblis Ross 51 Hxdropsxche bronia Ross 52 Hxdropsxche centra Ross 55 Hxdropsxche cheilonis Ross 57 Hxdropsxche cockerelli Banks 58 Hxdropsxche etnieri Schuster and Talak 59 Hxdropsxche macleodi Flint 60 Hxdropsxche morosa Hagen 62 Hxdropsxche oslari Banks 66 Hxdropsxche piatrix Ross 68 Hxdropsxche slossonae Banks 70 Hxdropsxche sparna Ross 74 Hxdropsxche tana Ross 77 Hxdropsxche xenada Ross 79 Hxdropsxche venture Ross 80 Hxdropsxche xexa Ross 81 Hxdropsxche walkeri Betten and Mosely 83 Hxdropsxche species (San Bernardino) 85 Hxdropsxche species (Snake River) 86 Hxdropsxche species (British Columbia) 87 Ph\logenetic Significance of Larval Chaetotaxal Characters 88 Acknowledgements 90 Literature Cited 91 A Systematic Study of Nearctic Larvae of the Hxdropsyche morosa Group (Trichoptera: Hydropsychidae) Abstract A system of taxonomic characters based on primary and secondary setae is developed and applied to identification of larvae of the Hydropsyche morosa (formerly bifida) species group known in North America. Diagnoses are provided for final instar larvae of H. aenigma Schefter. Wiggins, and Unzicker. alhedra Ross, alternans (Walker), amblis Ross, bronta Ross, centra Ross, cheilonis Ross, cockerelli Banks, etnieri Schuster and Talak, macleodi Flint, morosa Hagen, oslari Banks, piatrix Ross, slossonae Banks, sparna Ross, tana Ross, venada Ross, ventura Ross, vexa Ross, and walkeri Betten and Mosely. Of the Nearctic species known in the morosa group. H. abella Denning, andersoni Denning, cora Denning, dorata Denning, intrica Denning, protis Ross, and vanaca Denning remain unas- sociated in the larval stage, although diagnoses for three unnamed species known only as larvae are also provided. Secondary setal types are defined and illustrated, and a key is provided to the Nearctic larvae now known; distribution of each species is summarized. Characters based on setae appear to be less variable over the entire range of each species than the traditional characters of colour, and for the most part they are concordant with genitalic characters, suggesting that larval chaetotaxy is likely to provide useful data for classification and phylogeny in the Hydropsychidae. INTRODUCTION More than 80 species of Hydropsyche are known in North America, their larvae abundant in running water habitats. Although discrimination of species among the adult stages has developed with growing precision, identification of the larvae is a problem of long standing. Taxonomy of larvae based largely on markings of the head u as introduced by Ross (1944) for a number of eastern species, and a major advance in larval identification was made by Schuster and Etnier (1978) with diagnoses for 39 eastern species based mainly on markings with some characters of setal form. Diagnoses based on head pattern were provided for three western species by Alstad (1980). The present study was prompted by problems of geographic variability in head markings which made existing diagnoses ineffective over the full geographic range of man> species, particularly for northern populations of species originally characterized in the southeast. Moreover, even with larval/adult associations from populations over 1 much of the range, larvae of several species were inseparable because of intergradation of traditional characters. The objective of the present study was, then, to discover diagnostic characters that were less variable over the entire range of the species, and appropriate for discrimination among similar species. New suites of setal characters were found which satisfied these criteria fairly effectively. Some similar characters were employed by Smith and Lehmkuhl (1980) in diagnoses for four species which appeared during the final stages of the present study. THE HYDROPSYCHE MOROSA GROUP Because Hydropsyche bifida Banks has been shown to be a junior synonym of H. morosa Hagen (Schefter and Unzicker, 1984), the bifida species group is now known as the morosa group. SYSTEMATICS Approximately 200 species of Hydropsyche , distributed throughout all biotic regions of the world except the Neotropical, are divided into species groups: the morosa, depravata, scalaris, and cuanis groups in North America; the fulvipes-instabilis and simulans groups in Europe; the brxanti-celebensis-anmdata group in southeast Asia; the propinqua group in Africa. The Eurasian nevae group (Schmid, 1961) and penicillata group (Schmid, 1965), combined by Botosaneanu (1970) as the nevae group, should be incorporated in the morosa group along with the Palaearctic H. silfvenii. Approximately 15 species of the morosa group have ranges in Asia, two occur in Siberia and Europe, and 21 in North America. Traditionally the morosa group has been distinguished from other Nearctic Hydropsyche species on the basis of male genitalic characters. Homologies of the phallic structures in Hydropsyche have been interpreted differently by various authors (Nielsen, 1957, 1981; Ross and Unzicker, 1977; Schmid, 1979, 1980), and we are employing a synthesis of terminology derived from Schmid (1979, 1980) and Schefter and Unzicker (1984), until a phylogenetic assessment of the whole of Hydropsyche and related genera has been completed on a world-wide basis. In contrast with the entirely sclerotized phallotheca of the depravata, scalaris, and cuanis groups, the phallus of the morosa group species (Figs. 1-5) comprises a sinuate, tubular phallotheca into which is inserted dorsally in the distal portion a complex dorsolateral membrane, probably a modified endotheca (F. Schmid, pers. comm.) surmounted by a pair of ovoid sclerotized processes, the phallotremal sclerites (parameres, Nielsen, 1981). These dorsal sclerites articulate with an internal ejaculatory structure and the proximal membrane may be relatively unmodified as in H. oslari (Fig. 1) or be more elaborately lobed and armed with spicules or spines as in the other species (Figs. 2-5). The apex of the phallotheca (ventral endothecal lobe, Ross and Unzicker, 1977) is modified as well, usually partially membranous and in most cases equipped with eversible or permanently everted membranous lobes tipped with spicules. Nielsen identified the gonopore as the distal opening of the ejaculatory duct near the apex of the aedeagus, flanked by inner lips ( 1957) or parameres (1981); Ross and Unzicker (1977) placed the gonopore in the proximal cavity of the phallobase, opening into a large endophallus occupying much of the phallic cavity. and apparently opened and closed by phallotremal sclerites Hanking the distal pore, or phallotreme. Schmid's (1979) comments draw attention to the difficulties raised in phylogenetic interpretation by inconsistencies in phallic homologies. The tenth abdominal segment bears two fingerlike apical extensions (paraprocts, Nielsen. 1981) (Fig. lc) absent in most other Hydropsyche species groups, although present in the Asian bryanti-celebensis-annulata group. Internal abdominal glands, characteristic of many families of Trichoptera, are present and well developed in the morosa group although greatly reduced in the other species of Hydropsyche (Schuster, 1977). Abdominal segment X is distinctive in morosa group females, bearing an arched row of setae adjacent to the invaginated clasper receptacle (Figs. 6-8). Pupae of the morosa group bear a pair of dorsal hook plates on the second abdominal segment which are lacking in other species of Hxdropsxche (Schuster, 1984). All Hxdropsxche larvae bear several different types of secondary setae, described in detail below, but the morosa species group is distinguished from others by the absence of minute, often colourless spines on the dorsal surface of at least the first three abdominal segments; these spines occur on all abdominal segments in the depravata, scalaris, and cuanis species groups. Larvae of Hxdropsxche are of the typical hydropsychid form (Wiggins, 1977), with a quadrate to globose head, flattened dorsally, straight or slightly curved frontoclypeal sutures, the ventral apotome divided into a large and roughly triangular anterior portion, and a minute posterior triangular part connected by the ventral ecdysial suture. Meso- and metanotal sclerites lack transverse ecdysial sutures, and the foretrochantin is forked. Abdominal gills occur as single ventromedial! stalks and bifid ventrolateral stalks bearing short filaments, and sometimes single lobelike filaments laterally on at least abdominal segments I to VII. Hxdropsxche is distinguished from other hydropsychines by the paired ventral sclerites of abdominal segment VIII and the large, subrectangular prosternal sclerites (Wiggins, 1977). Further distinction between Hxdropsxche and Cheumatopsyche is in the primary setation of the head and prothorax (Mackay, 1978). Whereas head setae 2, 3, and 14 and pronotal seta 22 (sensu Williams and Wiggins, 1981) in Cheumatopsxche are thin, finely tapered, and usually more than one-half as long as the head or thorax, in Hxdropsxche the same setae are usually less than one-half the length of head or prothorax and, although frequently finely tapered as well, appear thicker and stiffer. The morosa group of Hxdropsxche was recently transferred to the genus Sxmphitopsxche Ulmer, although as a separate subgenus Ceratopsyche (Ross and Unzicker, 1977). Shortcomings in the genitalic homologies employed in that study have been pointed out by Schmid (1979), but one of the strongest reservations about the taxonomic conclusions arises from the fact that many groups within the Hydropsychinae were not included in the analysis. More recently Ceratopsyche was elevated to full generic status (Nielsen, 1981) to include the morosa group of North America and some European species. It has long been a tenet of systematic biology that relationships among taxa comprising a group such as the subfamily Hydropsychinae can be accurately assessed only after making an exhaustive analysis of many characters of representatives of the world's fauna. Until this has been done in the Hydropsychinae, we take the position that taxonomic proposals resulting in Figs. 1-5. Genital segments, male. 1 //. oslari. a) Lateral view. b) Tip of phallotheca, dorsal view. c) Apical extensions of abdominal segment X, dorsal view. 2. H morosa. a) Lateral view. b) Eastern form, tip of phallotheca, dorsal view. c) West/central form, tip of phal- lotheca, dorsal view. H. venruru. a) Lateral view. b) Tip of phallotheca, dorsal view. H. alternans. a) Lateral view . b) Tip of phallotheca, dorsal view. // amblis. Lateral view. ams /tT\Q _ _; flange 6 7 Figs. 6-8. Genital segments, female, lat- eral view showing receptacle of inferior appendage. 6. H. oslari. 7. H. ventura. 8. H. morosa. Abbreviations for genital segments: ae apical extension of abdominal segment X aJ apicolateral membrane als spicules of apicolateral membrane \J3 \ setae am ams asip dl dls en ph pts ria sb IX X 8 apical membrane spicules of apical membrane apical segment of inferior appendage dorsolateral membrane spur of dorsolateral membrane endophallus phallotheca phallotremal sclcrite receptacle of inferior appendage sclerous band abdominal segment IX abdominal segment X nomendatorial changes are premature. Morover, the monophyletic sets of species within Hydropsyche sensu Into are more appropriately expressed as subgenera and species groups because, as stated by Schmid (1979), their recognition as coordinate genera will become a precedent by which several large genera in the Trichoptera could be subdivided with equal justification; we are not convinced that generic fragmentation is a constructive development for the taxonomy of Trichoptera. This study is concerned with larvae of Nearctic species of the//, morosa group, as listed below; species marked * are not treated because no larval material was available. Hydropsyche abella Denning* aenigma Schefter, Wiggins, and Unzicker alhedra Ross alter nans (Walker) amblis Ross andersoni Denning* bronta Ross centra Ross cheilonis Ross cockerelli Ross cora Denning* dorata Denning* etnieri Schuster and TaJak H. intrica Denning* macleodi Flint morosa Hagen oslari Banks piatrix Ross protis Ross* slossonae Banks sparna Ross tana Ross vanaca Denning* venada Ross ventura Ross vexa Ross walkeri Betten and Mosely BIOLOGY Larvae of Hydropsyche species are widespread throughout the running water continuum, with the scalaris and depravata groups occurring primarily in downstream areas and morosa group larvae in summer-cool upper reaches of the stream. Although morosa group species are not usually found in torrential headwaters, H. sparna has been collected in cold, turbulent waterfall basins as well as a wide variety of other habitats, and some species, notably H. etnieri and //. piatrix, are apparently restricted to permanent spring-fed streams. H. alternans, although frequently found in large, fast rivers and lake outflows, also occurs along wave-washed shores of lakes. Hydropsyche larvae attach fine-meshed silken nets to permanent substrates in moving water. Oriented in the current to filter suspended organic particles, the nets of different species vary in mesh size or location within the stream. At the edge of the net is a silken retreat, covered with sand grains or organic material, in which the larva lies concealed. Hydropsyche larvae are generally omnivorous, feeding on a variety of suspended organic materials including detritus, various invertebrates, algae, and diatoms, the latter also being scraped from algal mats which may accumulate near the opening of the larval retreat (Fuller and Mackay, 1980). RANGE Nearctic species o( the Hydropsyche morosa group, with the exception of H. cheilonis, occur throughout the boreal forest biome and its ecotone extensions southwards into the Cordilleran and Appalachian montane forests (Ross, 1963, fig. 5), although no single species is distributed across the whole of North America. Three major range types can be delineated as follows: Northern transcontinental species occur from Atlantic coastal watersheds across Canada and the northern United States to the northern Pacific coastal ranges, with northern limits at the tree line and southern limits roughly those of the boreal forest biome; species in this group may also extend southwards along the Rocky Mountains and/or the Appalachians. Species with northern transcontinental ranges are H. alternans, alhedra, morosa, and slossonae . Eastern and northeastern species are either restricted to small areas of the Appalachians (H. macleodi, H. etnieri), or the Ozarks {H. piatrix), present only in the temperate deciduous forest biome of the south-central and midwestern United States (H. cheilonis), or are more widespread, extending through the Appalachian Mountains, northeastwards to Newfoundland, and northwestwards as far as the eastern slopes of the Rocky Mountains. Northern limits of this group lie considerably south of the tree line, with the southern limits variable; H. bronta has a widespread range within this group, and H. ventura is a species with a limited eastern range. Species with western ranges are either widespread from the southwestern states and Mexico northwards into Alaska and the Yukon (H. oslari, H. cockerelli), or are more restricted (H. amblis and H. centra in the Pacific Northwest, H. venada in Arizona and New Mexico). MATERIALS Material examined in this study was obtained from several sources. The extensive collection of adult and immature Hydropsyche in the Department of Entomology, Royal Ontario Museum, and the many specimens collected during the course of the study provided the major portion; all material not otherwise indicated by acronym (see below) is deposited in the ROM, with that collected since 1978 bearing six-digit field site numbers. The geographic scope of the study has been broadened through loans and gifts of additional material from these institutions and individuals: D. G. Cobb and J. F. Flannagan, Freshwater Institute, Winnipeg; P. L. Flannagan, Manitoba Department of Natural Resources; O. S. Flint, National Museum of Natural History, Smithsonian Institution (USNMNH); D. Fowler, University of Central Michigan (DF); University of Minnesota Department of Entomology collection; R. J. Mackay, University of Toronto; J. A. Nasca, Buffalo, New York; A. P. Nimmo, University of Alberta; D. E. Ruiter, Denver, Colorado (DER); G. A. Schuster, Eastern Kentucky University (GAS); S. D. Smith, Central Washington University (SDS); M. J. Stansbury, Oregon (MJS); L. Tsomides, University of Maine (UM); J. D. Unzicker, Illinois Natural History Survey (INHS); J. S. Weaver, Clemson University (JSW). TECHNIQUES When larvae of unknown identity are encountered, there are two basic methods available for species discrimination, both widely employed for adult/larval species association in Trichoptera. The more precise is rearing sorted, field-collected larvae through to the adult stage, a process which can be difficult for hydropsychids because particular current and temperature regimes are often difficult to simulate. We have successfully reared Hydrupsyche larvae in the small plexiglass chamber recently developed by Mackay (1981). Larvae can survive several days" transport from collecting site to laboratory packed with damp moss or paper towelling in plastic bags in a container of ice. Living fifth instar larvae should be sorted under a dissecting microscope to ensure as nearly as possible that they are of the same species, and some preserved as larvae. The second method of larval/adult association involves repeated collecting at the same location until all life stages are obtained, or occasionally an opportunely timed single series yielding both larvae and mature pupae. The larval sclerites, shed at larval/pupal ecdysis and present in the intact case, along with the fully developed pharate adult, comprise a metamorphotype which is essential for positive larval/adult association. Larval identity, inferred from the exuvial sclerites in the pupal case, is still uncertain if species with similar pattern, size, and pupation time coexist in the same area of the stream, a situation encountered frequently. Moreover, setae are not retained on exuvial sclerites, and the connection between larval colour pattern and diagnostic setal patterns must be made on the basis of preserved whole specimens. It is necessary, therefore, to have identifiable larvae as well as metamorphotypes. Metamorphotypes should be processed carefully in order to preserve all elements present in the pupal case. The anterior end of the case is opened and the specimen carefully extracted into a dish of clean alcohol, the larval exuviae remaining in the posterior end of the case. The species can be identified if genitalia of the pharate adult are sufficiently sclerotized, and the larval sclerites removed and compared with mature larvae collected at the same site. Each metamorphotype, with case and larval exuviae, is stored in a separate microvial, and all vials from one collection are placed in a jar with the larval collection and properly documented. We have found that for pharate adults fixed in Kahle's solution, the genitalia are more readily cleared for species determination by immersion in KOH solution at room temperature for several hours or overnight; internal tissues preserved in Kahle's solution tend to resist maceration. The availability of metamorphotypes is often restricted to a brief period in the spring for univoltine species, and obtaining them may be further complicated by the migration of the mature larva from its filter- feeding location in the stream to an area more suitable for the sessile pupal stage. Thus while larval populations may be easily located and collected, pupae may be in different parts of the stream and attached to different kinds of substrate, or even buried within the substrate. Because trichopteran adults are mainly nocturnal insects, they are most effectively collected by light traps at night or by sweeping riparian vegetation during the day. These methods are, however, not appropriate for establishing composition of communities at a particular site because Hydropsyche adults may fly long distances from their larval habitat. Emergence traps positioned over small areas of substrate, although yielding localized distribution and emergence data, are spatially and 8 temporally limited as well as impractical lor extensive survej collections, Larvae mas be collected by hand picking, kick and Surber sampling, or colonization of artificial substrate; but whatever method is employed, the habitat must be thoroughK explored because most sites support more than one species of Hydropsyche. For taxonomic study, the best larval specimens are obtained by fixation in Kahle's solution (Wiggins, 1977). The tendency for internal decomposition and reduced colour patterning of alcohol-fixed larvae is a detriment to the study of larval characters. For this study, larvae of each species were cleared by immersion in KOH at room temperature, often for 24 hours, with the abdomen carefully cut from the rest of the bod\ . ensuring complete maceration of all tissue. Setation was examined, sketched, and photographed at x 63.5 magnification with a Zeiss dissecting microscope, using both reflected and transmitted light. Head capsules cleared and mounted in glycerin in depression slides were viewed at x 100 using a compound microscope. For the scanning electron microscope (SEM) micrographs, cleared specimens were mounted on stubs and airdried at room temperature before coating with gold for examination. In using the ke> . diagnostic setal characters require magnification of at least x 50. To obtain mean head capsule measurements, a number of larvae were measured from geographically separate populations whenever possible, or a selection of largest and smallest fifth instars from a single population were measured (Mackay, 1978); sample size is bracketed following measurements. CHAETOTAXAL CHARACTERS INTRODUCTION Although Hydropsyche larvae have been treated taxonomically by several authors in recent years (e.g., Ross, 1944; Lepneva, 1964; Wiggins, 1977; Schuster and Etnier. 1978), and some of the numerous and highly differentiated setal types have been described as morphological features (see Lepneva, 1964), setae with few exceptions have not been investigated as diagnostic characters within the genus. Ross ( 1944) and Schuster and Etnier (1978) distinguished//, morosa group larvae on the basis of dorsal abdominal setation. Schuster and Etnier distinguished//, piatrix larvae by the presence of large spinelike setae on the venter of the anal prolegs, and several species of the scularis group by the presence of bristlelike setae on the frontoclypeus. Mackay ( 1978) used characters of anterolateral pronotal setae to distinguish between Cheumatopsxche larvae, Hydropsyche sparna, and the other hydropsychid species in her study area. Smith and Lehmkuhl (1980) distinguished four morosa group species using colour patterns, morphometric comparisons, and secondary setation of the head capsule. Williams and Wiggins (1981) have re-examined existing setal nomenclature for the Trichoptera, proposing a new and unified system incorporating primary setae and sensory pits of all body parts, homologizing them among the caddisfly taxa. We have found that distribution and morphology of both primary and secondary setae provide diagnostic characters which are much less subject to geographic variability than colour patterns. MORPHOLOGY PRIMARY SETAE These setae are present on first instar larvae (Fig. 9) and persist in homologous positions through subsequent instars. Primary setae are therefore distinguished by position, rather than by morphology. Numbers used for primary setae in this study are those proposed by Williams and Wiggins (1981) in their comprehensive chaetotaxy for Trichoptera. Some primary setae on first instar larvae are plumose (Fig. 9), but primary setae of later instars are usually long, tapered, flexible, and may be either clear or dark (Fig. 24). Shorter and less flexible primary setae occur dorsally on the posterior parietal sclerites (e.g., head seta 17), dorsally and laterally on the thoracic notal sclerites (thoracic setae 22 and 5), and in some species pronotal seta 22 is very short and cylindrical or moderately long and slightly tapered. SEM study reveals that head seta 17 has a tubular structure with a distal pore (Fig. 10), as does the shorter pronotal seta 22 (Fig. 1 1); head seta 14, although longer and more flexible than seta Fig. 9. First instar larva, Hydropsyche s/>.. showing primary Notation for Hydropsyche 10 17. also has a distal pore in some species. Although primary setae of the head do not provide the diagnostic characters for larvae in this study, the length of pronotal seta 22 is used to distinguish subgroups of species. Primary setae on the legs, distinguished b\ their position, are often accompanied by long secondary setae or shorter spikelike setae (Fig. 26). Presence or absence, and colour of setae 1,2, 3. and 5 on the trochanter, and setae 3 and 4 on the femur also furnish diagnostic characters (Figs. 39-44.53.54.58-61). SECONDARY SETAE Secondary setae arise in various positions on the body in instars II to V. Abundant and diverse, the) provide a rich source of chaetotaxal characters. The designation, morphology, and distribution of diagnostic types recognized in this study are as follows: Is Long slender setae are similar in appearance to long primary setae, may be clear or dark, and are usually located close to a primary seta; found on head, notal, and leg sclerites, and anal prolegs (Figs. 35-38,39-42,56). ap Acuminate peg setae are short, bristlelike, distinctly tapered, clear (Fig. 28) or dark (Fig. 25), and are usually erect or inclined anteriorly on head and thoracic notal sclerites. SEM study reveals a fluted, tapering tubular structure, the distal pore with a smooth aperture (Fig. 12). tp Truncate peg setae are short, bristlelike, cylindrical in shape (Fig. 13) ordistally enlarged (Fig. 14), clear (Fig. 27a) or dark (Fig. 31), and are usually erect or inclined posteriorly on head and thoracic notal sclerites. Study by SEM reveals a fluted, sometimes finely grooved, tubular structure, with the distal pore crenulate (Fig. 14). dorsolaterally compressed (Fig. 10), or unelaborated (Fig. 13). bl Brushlike setae are usually clear, very short, and inconspicuous under a dissecting microscope. Located on the frontoclypeus of several western species, the regularly spaced alveoli of these setae give the sclerite a punctate appearance (Fig. 27a). The presence of brushlike frontoclypeal setation is most easily detected by gently cleaning any detritus from the head and viewing it obliquely or laterally so that light directed through the minute, clear setae is visible. Examination with SEM shows the setae arising from a short fluted base, and distally dissected into 8 to 10 filaments (Fig. 15). hi Hairlike setae are short, appressed, flexible, and present on most cuticular and sclerotized body surfaces. While the morphological diversity of the hairlike setae on the head capsule is not discernible under a dissecting microscope, study by SEM or examination of a cleared head capsule under a compound microscope reveals a variety of forms. Simple whiplike setae (Fig. 16) may be asymmetrically bifurcate, bifid, trifid, or have four to five filaments (Figs. 17,18). Fine structure of hairlike setae can vary within species and is therefore not useful as a diagnostic character. si Spikelike setae are sharp, inflexible, and may be short or medium long, clear reddish, clear tan, or dark. They are present on leg sclerites (Fig. 26), and anal prolegs (Fig. 35). Some spikelike setae have prominent sockets and are similar to the spikelike setae found on the ventral sclerites of abdominal segments VIII and IX (Fig. 35); these may be clear reddish or clear tan, or occasionally opaque red, and their arrangement on ventral membranous areas of the anal prolegs is diagnostic. 11 sh Scale hairs are erect or semiereet abdominal setae, clavate (Figs. 19,20) or flattened and conspicuously wider than adjacent hairlike (hi) setae (Fig. 21) in some species, and are homologous with the club hairs of Schuster and Etnier (1978). They are mingled with appressed hairlike (hi) setae dorsally and occasionally laterally on abdominal segments (Figs. 65,66). SEM reveals a fluted structure with a terminal pore. Figure 21 shows abdominal setae in//, betteni, a species of the depravata group; note the wide, flattened scale hair (sh), and also the minute spines (ms) diagnostic for depravata, scalaris, and cuanis species groups. Other specialized but nondiagnostic secondary setae are the pectinate setae present on the lateral margins of the labrum (Fig. 22), the featherlike setae on the proximal leg segments illustrated by Jansson and Vuoristo (1979), and the brushlike setae on the anterior frontoclypeal margin (Fig. 23). Colours of setae are very important in these diagnoses, and yet the vocabulary available to describe subtle differences is inadequate. We have tried to convey a visual impression — setae designated as "clear" may be hyaline, golden, orange, red, or tan, but they share the property of being transparent. On the other hand, "dark" setae are not necessarily opaque, but are simply darkly pigmented and may be brown or black, opaque or slightly translucent. A frontoclypeus "lacking apparent setation" may bear fine, clear, and inconspicuous hairlike (hi) setae which are often not visible under a dissecting microscope. Describing larval colour patterns is equally difficult, and we use "light" and "dark" to imply contrasting colours — "light" may be yellow or tan, whereas "dark" may be tan, brown, or black, relative to the contrasting area. Figs. 10-23. SEM photographs of setae. 10. Parietal, seta 17, truncate peg (tp) and brushlike (hi) setae; H. sp. (San Bernardino), x 860. 11. Pronotum, anterolateral seta 22; H. sparna, x 1300. 12. Parietal, acuminate peg (ap) seta;//, bronta, x 4000. 13. Parietal, truncate peg (tp) seta;//, sparna, x 4000. 14. Parietal, truncate peg (tp) seta;//, walked, x 4000. 15. Frontoclypeus, brush! ike (bl) seta;//, sp. Snake River, x 1800. 16. Parietal, hairlike (hi) seta;//, bronta, x 1800. 17. Parietal, hairlike (hi) seta; H. walked, x 1800. 18. Parietal, hairlike (hi) seta; H. cockerelli, x 1800. 19. Abdomen, erect, clavate scale hair (sh);H. sp. (San Bernardino), x 1400. 20. Abdomen, erect, flattened scale hair (sh); H. alhedra, x 1400. 21. Abdomen, erect, flattened scale hair (sh) and minute spines (ms)] H. betteni, x 1030. 22. Labrum, lateral pectinate setae;//, alhedra, x 1300. 23. Frontoclypeus, anterior margin; //. alhedra, x 2000. 12 16 DISTRIBUTION HEAD The anterolateral comer of the frontoclypeus bears, in addition to setae 2 and 3, several secondary peg setae identical to those adjacent on the parietal sclerite. The remainder of the frontoclypeus may be free of secondary setae (as in Figs. 25,28,45). ma\ bear appressed acuminate peg (ap) setae posteriad of the tentorial ridge (as in Figs. 57.62). or erect truncate peg (tp) setae near the frontoclypeal sutures (as in Figs. 31 .46). Many erect or semierect acuminate peg (ap) setae are present over the entire frontoclypeal surface in H. macleodi (Fig. 30), while clear or dark, short, inconspicuous brushlike (bl) setae cover the frontoclypeus in several of the species found in the Rocky Mountains and westwards (Fig. 27). Frontoclypeal setation is best seen in dorsal view, especially in species with checkerboard coloration. Appressed acuminate peg (ap) setae near the lateral and posterior angles of the frontoclypeus are usually evident in light areas of the head colour pattern. Specimens 2-3-4 (probably)/ appressed hi setae,^ clavate sh setae /^ ventral sclerite of vni abdominal segment IX, si setae with prominent sockets Fig. 24. Fifth instar larva, H. bronta. 17 with dark heads should be viewed in lateral aspect so that otherwise inconspicuous setae may be detected. Clear, inconspicuous brushlike (bl) setae are often discernible only by light directed through them in lateral view. If the head capsule is carefully cleaned of detritus with a soft brush, the frontoclypeal setation can be seen in both dorsal and lateral view. On the parietal sclerites secondary setae can be uniform in length and morphology, or they can be varied. By examining each specimen from the same aspect (as in Figs. 29,30) the characteristic setation occurring near the frontoclypeal suture can be seen. The truncate peg (tp) setae are usually erect and may be inclined posteriorly; acuminate peg (ap) setae are usually inclined anteriorly or appressed. Some species, notably H. alhedra and H. sparna, have peg setae of intermediate form, i.e., tapered and truncate. Brushlike (bl) setae may be mingled with peg setae, although more commonly hairlike (hi) setae are present on the parietals, sometimes as fine, clear, inconspicuous setae which may also be present on the frontoclypeus (Fig. 16), or as more conspicuous hairlike (hi) setae evident in a lateral view (Figs. 48,62). In most species, the lateral parietal areas bear more and longer acuminate peg (ap) setae than truncate peg (tp) setae, while the areas dorsad of the eyes bear denser and longer truncate peg (tp) setae than other areas of the head. THORAX The pronotum bears a prominent primary seta near each anterolateral corner at position 22 (Figs. 25,32-34); a long, finely tapered seta is typical of most species, including those with checkerboard head patterns (Fig. 57), while a short, blunt seta (less than one and one-half times the length of the adjacent peg setae on the pronotal surface) occurs in most of the remaining species (Fig. 31). H. alhedra larvae show some variation in this character, as do several western species, the anterolateral seta being two to five times the length of adjacent secondary setae and tapered but apically truncate (Figs. 33,34). All three thoracic notal sclerites may have fine appressed hairlike (hi) setae, tapered, bristlelike acuminate peg (ap) setae inclined anteriorly or appressed, and erect, blunt, bristlelike truncate peg (tp) setae, often inclined posteriorly on the meso- and metanotum. The truncate peg (tp) setae are usually the only short, erect setae on the metanotum and are mingled with appressed hairlike (hi) setae and minute spines. Minute spines, outgrowths of the cuticle which are not articulated (as in Fig. 21), present on the meso- and metanotum, are detected by using transmitted light on cleared specimens. Meso- and metanota often have a primary seta at position 5 (Fig. 25). LEGS The legs also bear abundant and diverse setal types, some of which may be vibration receptors (Jansson and Vuoristo, 1979). The diagnostic setae, however, are long and tapered primary setae (as in Fig. 26), usually darkly pigmented and conspicuous. The procoxa in all species bears at least one long primary seta mesolaterally at position 1 (Figs. 26,63). Some species have a long secondary seta, and/or sharply tapered spikelike (si) setae on the same surface (Fig. 64). The mesotrochanter bears a dark primary seta at each of positions 2, 3, and 5, and there may be long secondary setae near position 3(Figs. 39,41,58,60). The mesotrochanter of some species bears a dark primarj seta at position 1, usually slightly shorter than the other three primary setae, but darkly pigmented and conspicuous (Figs. 53,54). Clear spikelike (si) setae are IX frontoclypeus lacking SVV apparent setation \\ 22 long, tapered Fig. 25. H. slossonae, head and thoracic segments, dorsal view showing setation (in part). 19 / ^ 4&W A Fig. 26. H. sparna, legs, posterior view showing setation. abundant on the distal leg segments, and on the mesotrochanter seta 1 may be distinguishable as a clear seta, longer than adjacent clear spikelike (si) setae. A dark seta 1 may also be present on one or both sides of occasional specimens in several species. This is critical in the distinction of H. slossonae and H. aenigma where characters of size, colour, and distribution may not discriminate between them. The mesofemur shows characteristic setation along the distolateral margin when examined from the posterior aspect (usually best accomplished by holding the larva head downwards). There may be only two dark long primary setae, one at each of positions 3 and 4, in addition to the invariable dark seta at position 2 (Fig. 39), or near these two setae there may be one or two shorter but equally dark long slender (Is) setae (Fig. 60), or a cluster of three or more dark long slender (Is) setae near position 3, sometimes extending to position 4, as is characteristic of//, slossonae (Fig. 41 ). This character, in some species, can vary considerably among populations. Clear long slender (Is) or spikelike (si) setae are also present on the distolateral margin of both meso- and metafemur. 20 The metatrochanter o( most species has a single dark primary seta at each ol positions 2 and 3 (Fig. 40). H. oslari , H . walkeri . and occasionally H. alhedra show a dark primary seta at position 3 and a clear, inconspicuous primary seta at position 2 (Fig. 44). Both the second and third trochanters have other clear long slender [Is) setae distributed on the sclerite. The metafemur bears, in addition to the invariable seta 2, a dark primary seta at each of positions 3 and 4 (Fig. 40) or a single dark primary seta at position 3, and a clear, inconspicuous primary seta at position 4 (Figs. 43.44,61). ABDOMEN Setation on most segments consists of fine, black, appressed hairlike (hi) setae dorsally , laterally, and ventrally, with two or three long, fine primary setae at what is probably position 2-3-4 and one primary setae at position 5 (Fig. 24), and erect or semierect, clavate (Fig. 65) or flattened (Fig. 66) scale hairs (sh setae) dorsally and laterally. Minute spines are present ventrally on abdominal segment IX. The ventral membranous surface of the anal proleg bears several different types of setae in addition to the covering hairlike (hi) setae and minute spines. Sharply tapered, dark or clear spikelike (si) setae (as in Figs. 38,50) or sharp, reddish spikelike (si) setae (some with prominent sockets), either straight (as in Fig. 36) or hooklike (as in Fig. 49), are mingled with the hairlike (hi) setae. The triangular ventral sclerite of abdominal segment IX bears 20 to 50 reddish spikelike (si) setae with prominent sockets, and these are used as a reference in descriptions of some of the spikelike (si) setae on the anal proleg. OTHER CHARACTERS The number and arrangement of abdominal gill trunks is constant in all known Hydropsyche morosa group species, although the number of filaments on each branch may be distinctive for certain species. Characters involving gills are based on the third abdominal segment. Larvae of the very closely related species//, ventura and H. macleodi are distinguished by the difference in numbers of gill filaments, in addition to the distribution of acuminate peg (ap) setae on the frontoclypeus. Many species share a similar head colour pattern, and the well-established term "checkerboard" is used in this study to indicate the basic pattern of seven contrasting light patches on the frontoclypeus: one anterior, two anterolateral, one central, two posterolateral, one near the posterior frontoclypeal angle, and various light areas dorsally and laterally on the parietal sclerites. Ten of the known H. morosa group larvae share the characteristic checkerboard-patterned head, often intraspecifically variable, as described above and illustrated in Figures 71 to 85. Some species with patterns other than checkerboard are geographically variable in colour (H. slossonae, H. alhedra, H. sparna), while in others variability has not been demonstrated (//. etnieri , H. amblis). Improperly preserved larvae, or preserved larvae exposed to light for long periods of time, tend to lose contrast in sclerite or setal colours, appearing uniformly reddish brown or sometimes black. 21 KEY TO NEARCTIC LARVAE OF THE HYDROPSYCHE MOROSA GROUP Frontoclypeus with, in addition to peg setae near anterolateral corners, numerous minute, clear or tan bl setae; viewed laterally, setae evident by light directed through them; viewed dorsally, setae visible, or clear and inconspicuous with sclerite appearing punctate, especially on posterior surface (as in Fig. 27). Rocky Mountains and westwards 1' Frontoclypeus bare (as in Figs. 25,28), or with occasional tp or ap setae near frontoclypeal sutures (as in Figs. 31,57), or with many ap setae on surface (as in Fig. 30). Several peg setae occur near anterolateral corners. Widespread Fig. 27. Head, dorsal view, showing partial setation and texture. a) H. sp. (San Bernardino). b) H. sp. (British Columbia), detail of frontoclypeus, posterior angle. c) H tana, detail of frontoclypeus, posterior angle. 22 frontoclypeus lacking \ * V apparent setation l/sfr£ y/sA clear ap on parietal frontoclypeus with a few erect tp near sutures erect ap and tp on parietal /^/-^ frontoclypeus with ap scattered on entire surface Figs. 28-30. Head, showing setation (in part). 28. H. venada, dorsal view. 29. H. sparna, oblique view. 30. H. macleodi, oblique view. 23 2(1) Mesofemur in posterior aspect with setae 3 and 4 accompanied by several dark, long secondary (Is) setae (as in Fig. 41). Idaho, Oregon H. sp. (Snake River) 2' Mesofemur in posterior aspect with long, dark primary seta at each of positions 3 and 4, no more than one dark, long secondary seta near position 3 or 4 (as in Fig. 60), although tan or clear setae are present 3 3(2') Parietal sclerites with dorsal and lateral peg setae inconspicuous, clear yellow or tan (Fig. 27a). Frontoclypeal bl setae clear, inconspicuous in dorsal aspect, but pubescent effect visible in profile. Southern California H. sp. (San Bernardino) 3' Parietals with dorsal and lateral peg setae brown, conspicious (as in Fig. 45). Frontoclypeal bl setae either conspicuous or inconspicuous 4 4(3') Frontoclypeus with bl setae tan or brown, conspicuous on yellow or tan sclerite (Fig. 27b). Alaska and British Columbia . . . H. sp. (British Columbia) 4' Frontoclypeus with bl setae transparent, inconspicuous on dark sclerite (Fig. 27a) 5 5(4') Frontoclypeus with alveoli of bl setae closely spaced, sclerite appearing rough, densely punctate (as in Fig. 27a). Head capsule width greater than 0.9 mm, posterior area of parietals uniform dark brown; light area around eyes only (Fig. 87). Pacific Northwest H. amblis 5' Frontoclypeus with alveoli of bl setae widely spaced, sclerite smooth, not densely punctate (Fig. 27c). Head capsule width less than 0.9 mm, posterior area of parietals light in colour, the parietal suture suffused with dark pigment (as in Fig. 84). Montana, Idaho, California, British Columbia H. tana 6( 1 ') Pronotum with anterolateral seta 22 long, at least 2 times length of adjacent peg setae, and tapered (Figs. 24,25,33,34). Head with 24 parietal with dark ap and (p frontoclypeus with erect tp near sutures 22 short, truncate /T& " 22 snort' truncate 22 medium long tapered and truncate 22 long, with curved peg setae on anterior margin of pronotum Fig. 31. H. sparna, head and prothorax showing setation (in part). Figs. 32-34. Pronotum. anterolateral corner showing setation. 32. H. sparna. 33. H alhedra. 34. H. oslari. 25 various colour patterns, including checkerboard 7 6' Pronotum with anterolateral seta 22 short, one to one and one-half times length of adjacent peg setae, and cylindrical or slightly tapered (Figs. 31,32). Head with colour pattern other than checkerboard 20 7(6) Venter of anal proleg lacking clear reddish si setae on caudal lobes (Figs. 37,38). Head with various colour patterns 8 7' Venter of anal proleg with several clear reddish ,v/ setae on caudal lobes (Figs. 35,36,49). Head with checkerboard colour pattern 13 anal claw caudal ventral membranous area caudal lateral area few JJJi —clear reddish si « / 1 1/ w'tn Prom'nent ,lV '' 'Bl(- basal area c,eartan/ si lacking prominent sockets ventral sclerite with clear reddish si 49 50 Figs. 49,50. Left anal proleg and left side of abdominal segment IX, ventral view showing setation (in part). 49. H. piatrix. 50. H. sparna. setae (Fig. 33). Metatrochanter with setae 2 and 3 usually dark (as in Fig. 43). Venter of anal proleg with hi setae only; occasionally a few clear si setae on lateral areas (Fig. 37b) H. alhedra 12(9) Mesotrochanter with seta 1 present, dark, about one-half length of setae 2, 3, and 5 (as in Fig. 54). Head with checkerboard pattern. Beaverkill River, New York 12' Mesotrochanter with seta 1 reduced and clear (as in Fig. 39) or absent. Head usually with other than checkerboard pattern. Appalachians and northern transcontinental H. aenigma H. slossonae 13(7') Venter of anal proleg with reddish si setae stouter than those on ventral sclerite of 32 abdominal segment IX, their prominent sockets larger and darker than soekets of si setae on sclerite of venter IX (Fig. 49). Parietals with short, clear up setae of uniform length dorsall) near frontoclypeal suture (Fig. 52). Ozark Plateau of Missouri and Arkansas H. piutrix 13' Venter of anal proleg with .v/ setae clear reddish or tan, and same thickness or thinner than those on sclerite of venter IX, some with prominent sockets similar to those of si setae on sclerite of venter IX (as in Figs. 35,36). Parietals with various setation but not as above 14 frontoclypeus bare or with a few clear, erect tp parietal with clear, erect tp frontoclypeus lacking apparent setation parietal with clear, erect ap 52 Figs. 51,52. Head, oblique view showing setation (in part). 51 . H. alter nans. 52. H. piatrix. 33 5 2 3 frontoclypeus with a few appressed ap near lateral corners parietal with clear, erect and appressed tp and ap Figs. 53,54. Leg segments, posterior view showing setation. 53. H. ullernans, mesotrochanter and mesofemur. 54. H. vexa, mesotrochanter and mesofemur. Fig. 55. H. vexa, head, oblique view showing setation (in part). 34 14(13') Parietals with tp setae of uniform length dorsalh near frontoelypeal suture, up setae absent or ineonspieuous (Fig. 51) 15 14' Parietals with tp setae of various lengths mingled with op setae (as in Fig. 56) 17 15(14) Mesotrochanter with seta 1 clear and similar in length to adjacent setae (as in Fig. 41 ). Pacific Northwest H. centra 15' Mesotrochanter with seta 1 dark and much longer than adjacent setae (Fig. 53) 16 16(15') Parietals with tp setae clear (Fig. 51). Northern transcontinental H. alternans 16' Parietals with tp setae dark. Rocky Mountains and westwards H. cockerelli clear, erect and appressed ap and tp 14 at least half length of head 22 long, at least half length of pronotum Fig. 56. H. vexa, head and pronotum, dorsal view showing setation (in part). 35 17(14') 17' Mesotrochanter with seta 1 dark (as in Fig. 54). Venter of anal proleg with stout, curved si setae basally, some as stout as si setae on sclerite of venter IX (as in Fig. 35); thinner si setae on lateral surfaces and caudal lobes, mingled with numerous /;/ setae (as in Fig. 36). Pigmentation on pronotum appears freckled. Primary head and thoracic notal setae long, greater than one-half length of head (Figs. 55,56). Northern transcontinental from Quebec to Alberta H. vexa Mesotrochanter with seta 1 clear and similar in length to adjacent setae (as in Fig. 39). Venter of anal proleg with variable setation but not as above. Pigmentation on pronotum not freckled. Primary head setae less than one-half length of head frontoclypeus with Ob appressed ap near sutures parietal with erect and appressed, dark ap Fig. 57. H. bronta, head and pronotum, dorsal view showing setation (in part). 36 ■\^# 4 dark 4 clear Figs. 58-61. Leg segments, posterior view showing setation. 58. H. morosa west/central, mesotrochanter and meso femur. 59. H. morosa west/central, metatrochanter and metafemur. 60. H. morosa east, mesotrochanter and mesofemur. 61. H. morosa east, metatrochanter and metafemur. 37 parietal with erect and appressed , frontoclypeus with appressed ap near sutures hi conspicuous seta 1 seta 1 with dark hi and si adjacent 63 64 2-3-4 clavate sh \ appressed hi \ \\\ I 2-3-4 flattened sh I appressed hi 65 66 Fig. 62. H. bronta, head, oblique view showing setation (in part). Figs. 63,64. Procoxa, lateral view showing setation (in part). 63. H. bronta. 64. H. morosa. Figs. 65,66. Abdominal segment, dorsal view showing setation. 65. H. morosa. 66. H. alhedra. 38 18(17') Frontoclypeus lacking peg setae on posterior surface (as in Fig. 48), or with one or two dark, erect peg setae near posterior frontoclvpeal angle. Venter of anal proleg with a few clear reddish si setae which lack prominent sockets (as in Fig. 50). Southeastern and central H. cheilonis 18' Frontoclypeus with ap setae scattered on posterior surface, visible in dorsal view at lateral or posterior angle in light patches of colour pattern or in profile (as in Fig. 62). Venter of anal proleg with numerous and/or stout, reddish si setae, some with prominent sockets (Figs. 35,36) 19 19(18') Venter of anal proleg with a few clear reddish si setae, some on the basal area with sockets as prominent as sockets of si setae on ventral sclerite of abdominal segment IX, on basal area mingled with a few hi setae; thinner, pale red si setae distolaterally with few hi setae in this region (Fig. 35). Mesofemur with long, dark setae 3 and 4, usually with only clear si setae adjacent (Fig. 39). Procoxa with single long, dark seta 1 (Fig. 63), lacking adjacent dark Is or si setae. Widespread east of Rocky Mountains H. bronta 19' Venter of anal proleg with many clear reddish si setae, usually with sockets less prominent than those on ventral sclerite of abdominal segment IX, numerous basally and laterally, and mingled with numerous hi setae basally and distolaterally (Fig. 36). Mesofemur with dark si or Is setae near long, dark setae 3 and 4 (Figs. 58,60). Procoxa usually with several dark si setae mesolaterally in addition to seta 1 (Fig. 64). Northern transcontinental H. morosa 20(6') Frontoclypeus with many ap setae (Figs. 30,67) 21 20' Frontoclypeus lacking numerous ap setae, although there may be 2 to Map or tp setae on posterior surface (Figs. 29,68) 22 39 21(20) Abdominal gills of segment III with bifid outer trunk bearing 8 to 10 filaments on lateral branch, 5 to 7 filaments on mesial branch (Fig. 69). Abdominal sh setae flattened and conspicuously wider than adjacent appressed hi setae (as in Fig. 66). Frontoclypeus with numerous ap setae, most numerous on posterior surface of sclerite (Fig. 67). Eastern H. ventura 21' Abdominal gills of segment III with bifid outer trunk bearing six to seven filaments on lateral branch, four to six filaments on mesial branch (Fig. 70). Abdominal sh setae clavate but similar in width to adjacent appressed hi setae (as in Fig. 65). Frontoclypeus with ap setae scattered over entire surface of sclerite (Fig. 30). Restricted range in Appalachian Mountains H. macleodi 22(20') Parietals with closely spaced, dark, short ap setae of uniform length and inclined anteriad (Fig. 68). Frontoclypeus with distinctly wrinkled texture. Tennessee H. etnieri 22' Parietals with tp setae, sometimes mingled with ap setae, all setae of uniform length; all head setae erect (Fig. 29). Frontoclypeus smooth and shiny. Widespread through eastern North America H. sparna 40 frontoclypeus with appressed ap scattered on surface concentrated on posterior area frontotclypeus lacking apparent setation parietal with dark, erect ap lateral mesial lateral mesial 69 70 Figs. 67.68. Head, oblique view showing setation (in part). 67. H. ventura. 68. H. etnieri. figs. 69,70. Abdominal gill, outer bifid trunk showing filaments on mesial and lateral branches. 69. H. ventura. 70. H. macleodi . 41 72 77 78 79 Figs. 71-79. Head, dorsal view showing colour patterns. 71-73. H. bronta. 74,75. H. walker i. 76. H. bronta. 11-19. H. morosa. 42 5 % ¥fi 84 85 87 Figs. 80-87. Head, dorsal view showing colour patterns. 80-82. H. slossonae. 83. H. alhedra. 84. H . sparna 85. // alternans. 86. W. w.s/tin. 87. H. amblis 43 DIAGNOSIS AND DISCUSSION FOR SPECIES Hydropsyche aenigma Schefter, Wiggins, and Unzicker Hydropsyche aenigma Schefter, Wiggins, and Unzicker, 1986, holotype male, allotype female; type locality. Beaverkill River at Horton. Delaware County, New York. Larvae of this distinctive species were collected on several occasions in Delaware County, New York, from the Beaverkill River, and were later associated with the male and female. Larvae of Hydropsyche aenigma are described in this study for the first time. DIAGNOSIS This species has a typical checkerboard head pattern and shares the characters of a smooth frontoclypeus, nearly bare of secondary setae posteriad of the prominent tentorial ridge, with several other species. Numerous black ap setae on the parietals and the cluster of dark Is setae between primary setae 3 and 4 on the mesofemur distinguish it from similar species. These are the largest larvae known in the morosa group in eastern North America. The head pattern is similar to that of//, alternans (Fig. 85) but is very darkly pigmented in dark areas, contrasting with the light patches. This checkerboard species has been collected at only one site, where variability is seen in the number of frontoclypeal light patches — some specimens have three mesial patches, one anteriad, one posteriad of the central patch, similar to one form of//, slossonae . The more common pattern is a very dark, but typical checkerboard with seven light patches. The parietals have a dorsal light streak from the eyes posteriad to the mesial frontoclypeal angle. The posterodorsal light area of the head capsule is usually lightly suffused with brown pigment along the coronal suture. DESCRIPTION Head squarish, width 1.45-1.69 mm, length 1.66-1.85 mm (10 larvae). Frontoclypeus smooth, nearly bare of secondary setae, one or two erect tp setae may be near posterior frontoclypeal angle. Parietals with ap setae of uniform length, dense, black, erect or inclined; ap setae longer and sometimes translucent on anterolateral surfaces; tp setae dorsad of eyes; hi setae inconspicuous. Pronotum with anterolateral seta 22 long, dark, tapered; dorsally and laterally with ap setae, some as stout as parietal ap setae, black, inclined anteriorly, and some less stout than parietal ap setae, dark or translucent, appressed; hi setae inconspicuous. Mesonotum with seta 5 moderately long, dark, cylindrical or slightly tapered; dorsally and laterally with ap setae dark, inclined, mingled with dark, erect tp setae and conspicuous hi setae. Metanotum with seta 5 moderately long, translucent; dorsally and laterally with tp setae medium brown, distally expanded, those inclined anteriorly interspersed with similar setae inclined posteriorly. Procoxa with seta 1 long, dark, and several dark Is and si setae on same surface. Mesotrochanter with setae 2, 3, and 5 long and dark, with seta 1 also dark, shorter than other primary setae; mesofemur with setae 3 and 4 long and dark, with cluster of 44 dark Is setae between. Metatroehanter with setae 2 and 3 long, dark; metafemur with setae 3 and 4 long and dark. Abdomen with erect sh setae clavate, mingled with appressed hi setae. Ventral membranous area of anal prolegs with either black si setae basallv and laterally, mingled with /;/ setae; or black si setae basallv and laterally, interspersed with clear reddish ,s7 setae on lateral areas (some with prominent sockets less pronounced than the sockets of si setae on the ventral sclerite of abdominal segment IX), and mingled with dark /;/ setae. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 13-18; lateral branch, 20-23. BIOLOGY The Beaverkill River at the collecting site is 10 to 20 m wide and less than 1.0 m deep. Larvae were found in a turbulent riffle in 30 to 40 cm of water. The river flows out of a relatively undisturbed upland area and is a productive trout stream. Other Hxdropsxche present were H. slossonue and H. morosa. METAMORPHOTYPES EXAMINED NEW YORK: Delaware County, Beaverkill River at Exit 92 off Route 17, 6 V 82, #822504, holotype male, allotype female, reared, emerged 13 V 82. LARVAE EXAMINED NEW YORK: Delaware County, Beaverkill River at Exit 92 off Route 17, 12 IX 80, #801054 (30); 20 X 80. #801065 (20). Hxdropsxche alhedra Ross Hxdropsxche alhedra Ross, 1939, p. 67, fig. 7, holotype male; type locality. Black Gap. North Carolina. Hxdropsxche riola Denning, 1942, p. 49, fig. 4, holotype male, allotype female; type locality. Nine Mile Creek, Hennepin County, Minnesota. Syn. Schefter, Wiggins, and Unzicker, 1986. Hxdropsxche riola — Denning, 1943, pp. 133-134, figs. 22,23, female, pupa. Hxdropsxche racona Denning, 1965, p. 78, figs. 4,5, holotype male, allotype female; type locality, Albany County, Wyoming. Syn. Schefter, Wiggins, and Unzicker, 1986. Sxmphitopsyche riola — Schuster and Etnier, 1978, pp. 44-45, fig. 21, larva. Sxmphitopsyche alhedra — Schuster and Etnier, 1978, p. 45, fig. 22, larva. Larvae of Hxdropsxche alhedra and H. riola, distinguished in colour pattern by Schuster and Etnier (1978), were, in the course of this study, found to be the same in setal characters. By extensive field work in Ontario and Manitoba, larvae of two major colour morphs were associated with adult stages; a uniform dark brown H. alhedra, similar to that described by Schuster and Etnier, is as numerous in this part of its range as the patterned H. alhedra, formerly H. riola, which has a dark head 45 with two anterolateral light patches. Schuster (pers. comm.) collected population samples of very large, uniformly brown//, alhedra in Tennessee on many occasions, finding larvae and pupae present in the stream until April, but no mature larvae or pupae after a synchronous May emergence. The typical H. alhedra occurs in the Appalachians and is also widespread across the northern part of the continent. The large H. alhedra is restricted to cold, fast Appalachian streams, while other populations are usually collected in shallow riffle areas of streams of various size. DIAGNOSIS The uniform dark brown morph of Hydropsyche alhedra is similar to//, etnieri but can be distinguished by the dark, erect tp setae on the parietals, the flattened abdominal sh setae and the moderately long anterolateral pronotal seta 22, approximately three times the length of adjacent secondary setae. The patterned//, alhedra larva is not a typical checkerboard species although some populations examined contained a high proportion of individuals with a head pattern somewhat similar to a checkerboard type, consisting of two mesial and two lateral light patches anteriad of the tentorial ridge (Fig. 83). These patterned larvae can be readily separated from all checkerboard species except H. walked by setation of the anal proleg. H. alhedra larvae have long hi setae on the ventral membranous area, with occasionally one or two straight clear reddish or tan si setae occurring on lateral surfaces, while H. walkeri larvae have short hi setae on the venter of the anal proleg. H. alhedra also differs from H. walkeri in head setation: the parietals in H. alhedra have dark tp setae of unequal lengths dorsally and dark ap setae laterally, while the parietal setation of//, walkeri consists of dark tp setae of uniform length, usually distally enlarged, and lacks lateral ap setae. The anterolateral pronotal seta 22 of//. alhedra is of intermediate length (from 2 to 5 times the length of adjacent setae), and although tapered, it is usually blunt distally. H. alhedra could be confused with specimens of H. sparna having a slightly elongate pronotal seta 22, but the erect abdominal sh setae of//, alhedra are long and flattened, while erect sh setae on //. sparna are similar in length and width to the appressed hi setae. The head capsule of//, alhedra larvae may be uniformly dark brown (as in Fig. 84) or brown with two frontoclypeal anterolateral light patches anteriad of the tentorial pits; other variations consists of a faint median light patch anteriad of the tentorial ridge in addition to the anterolateral light areas, and a pseudocheckerboard head with a light brown or tan background with four light patches anteriad of the tentorial ridge, two lateral and two mesial (Fig. 83), resembling the four anterior spots of a typical checkerboard pattern. The full range of variability can occur in a single population, the monochromatic dark brown individuals appearing very different from the lighter, nearly checkerboard larvae. DESCRIPTION Head rectangular; width 1.37-1.45 mm, length 1.66-1.74 mm (6 larvae; population from Little River, Great Smoky Mountains National Park), width 1.04-1.21 mm, length 1.29-1.45 mm (19 larvae; populations from remainder of range). Fronto- clypeus lacking apparent setation, or with one to four erect tp setae near the posterior frontoclypeal angle. Parietals with dark, erect tp setae of unequal lengths, longer anteriorly; inclined ap setae, dark and clear tan, short on dorsal surfaces, longer laterally; hi setae inconspicuous against dark background, visible on light areas. 46 Pronotum with anterolateral seta 22 elear or tan, averaging three times the length of adjacent setae, tapered, and distally blunt; dorsally and laterally with up setae dark, inclined anteriorly; hi setae dark, conspicuous (distinetion between up and tp setae in this speeies is not always elear — they may be slightly tapered and apieally blunt). Mesonotum with seta 5 moderately long, light tan; dorsally and laterally with//? setae ereet, dark; up setae appressed, dark, thinner than those on pronotum; and hi setae dark, conspicuous. Metanotum with seta 5 moderately long, light tan; dorsally and laterally with tp setae dark, ereet and inelined posteriorly, and hi setae dark, conspicuous. Procoxa with dark seta 1 accompanied by one or more short, dark si setae. Mesotrochanter with setae 2, 3, and 5 long, dark; mesofemur with long, dark setae 3 and 4, often shorter, dark si setae between. Metatrochanter with long, dark setae 2 and 3 (occasionally seta 2 is clear); metafemur with long, dark seta 3, seta 4 clear or not distinguishable. Erect abdominal sh setae flattened. Venter of anal proleg with hi setae basally and laterally; on some individuals, a few thin, clears/ setae may be present either basally or laterally. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 9-10; lateral branch, 11-14. BIOLOGY Populations of the large Hydropsyche alhedra occur in the Middle Prong of the Little River in Great Smoky Mountains National Park, Tennessee, the collecting site described by Schuster and Etnier (1978) as 12 to 15 m wide, 0.2 to 1.0 m deep with large to medium-sized boulders and moderate to fast current. Larvae are found on larger rocks in white water areas, associated with Arctopsvche irrorata , Hydropsyche bronta, H. sparna, and H. slossonae . In the South Toe River in North Carolina, the large H. alhedra occurs with H. macleodi. Other populations of//, alhedra occur in small, cool streams and rivers although the larvae are apparently tolerant of organic enrichment. H. alhedra often occurs with H. slossonae throughout its north-east and north-central range. RANGE Hydropsyche alhedra occurs from New England in the east to the Yukon and Alaska in the west. Northern range limits are the Hudson Bay lowlands in Ontario, and northern Manitoba and Saskatchewan. Southern limits are North Dakota and Minnesota in the Midwest, and the Appalachians southwards to North Carolina and Tennessee in the east. METAMORPHOTYPES EXAMINED Large larvae. TENNESSEE: Sevier County, Hills Creek north of Tennessee 73, between Gatlinburg and Cosby, 11 IV 76 (5); Great Smoky Mountains National Park, Little River at Elkmont Campsite, 26 IV 80, GAS (3). Other metamorphotypes and associated larvae. MANITOBA: Duck Mountain Provincial Park, North Pine River, 29 V 81, #81 1078a (1 and 10 unpatt.). MINNESOTA: Winona County, 3.2 km south of Elba, middle fork of the Whitewater River at Minnesota 74 bridge, 24 VIII 76 (6). ONTARIO: Algoma District, Baldhead River at Highway 17, 7 VI 80, #801025 (1); Kenora District, Kiruna Lake, 12 VII 81, #81 1029 (3 and 30 unpatt., 30 patt. larvae); Sudbury District, Eastman Creek at 47 Highway 101, 55 km west of Timmins, 23 V 72, #720181 (8); Thunder Bay District, Cloud River at Cloud River Road, 10 VI 80, #801029 (1 and 60 larvae, most with light patt.); 4 VIII 80, #801065 (3 reared, emerged 27 VIII 80; and 10 larvae); stream at East Loon Lake Road, 4 VIII 80, #801045 (2 and 6 unpatt.); Joe's Creek, Sibley Provincial Park, 20 V 81, #811056 (2 and many unpatt. prepupae). LARVAE EXAMINED Large larvae. NORTH CAROLINA: McDowell County, Pisgah National Forest, South Toe River at Black Mountain Campground, 23 X 84, #840235 (20). TENNESSEE: Blount County, Great Smoky Mountains National Park, Middle Prong of the Little River at Tremont, 18 XI 75, GAS (2); Sevier County, Great Smoky Mountains National Park, Little River at Elkmont Campsite, 10 IV 81, GAS (5). Other larvae. ALASKA: Parks Highway, milepost 128.5, small stream crossing highway, 62°32'N by 150°14'W, 14 VII 82, #821 117a (4 unpatt.). MANITOBA: Duck Mountain Provincial Park, Cowan Creek, 28 V 81, #81 1077; Garland River, 1 VII 62 (7); South Duck River, Station C4, 28 X 80, #801068 (2 adults reared from unpatt. larvae); Norgate, stream at Baseline Road 1.3 km west of Highway 5, 28 X 80, #801067 (6 unpatt.); Riding Mountain National Park, Edwards Creek, 2 VII 62 (15 unpatt., 5 patt.). MINNESOTA: Winona County, 3.2 km south of Elba, middle fork of the Whitewater River at Minnesota 74 bridge, 24 VIII 76, GAS (10). NORTH DAKOTA: Pembina County, Icelandic State Park, Renwick Lake, Tongue River at Renwick Dam, 8 VII 81, #813013 (30, coll. with adults). ONTARIO: Cochrane District, Thunder Creek at Highway 101, 19 V 72, #720163; Kenora District, KirunaLake, 10 VII 81, #810023g(l unpatt., 5 pan.); Rainy River District, Quetico Provincial Park, French River at Highway 11 east of Dawson Trail Campground, 25 VIII 76, #760213 (5 patt.); Thunder Bay District, Crooks Township, Cloud River, 12 VII 80, #801039 (10 unpatt., 40 patt.); Dorion Township, Wolf River at Highway 17, 21 V 81, #811058 (10 unpatt., 5 patt.); Dublin Creek at Highway 17, 40 km west of Rossport, 19 VIII 80, #800160 (3 unpatt.); Jackpine River at Highway 17, 19 V 81, #811049 (10 unpatt., 5 patt.); Lismore Township, Little Whitefish River, 24 V 81, #81 1066 ( 15 unpatt., 15 patt.); North Mclntyre, Mclntyre River, 22 V 81, #81 1062; 3 km north of Highway 17 on Ouimet Canyon Road, Coldwater Creek, 10 VI 80, #801031 (1 patt.); Pearl, Pearl River at Highway 17, 12 VI 80, #801036 (10 patt.); 12 VII 80, #801042 (15 patt.); 21 V 81, #811059a,b (1 unpatt.); Sibley Provincial Park, Sibley Creek, 20 V 81, #81 1055a (30 larvae — most unpatt.); Sunshine, Sunshine Creek at Matawin River, 10 VI 80, #801030a (15 patt.); Thunder Bay, McVicar's Creek at Cumberland Street, 4 VIII 80, #801046 (5 unpatt., 30 patt.). SASKATCHEWAN: Goodsoil, stream on Highway 224, 16 VIII 70, #700549 (1 unpatt.); Meadow Lake, swamp ca. 11.3 km north on Highway 7, 14 VIII 70, #700539(1 unpatt.). YUKON: Klondike Highway, km 384, Tatchun Creek at Tatchun Creek Campground. 9 VIII 80, #800150, 800151 (10 patt). Hydropsyche alternans ( Walker) Philopotamus alternans Walker, 1852, p. 104, type locality, St Martin's Falls, Albany River, Hudson's Bay, Ontario. 48 Philopotamus indecisus Walker, 1852, p. 104. Syn. McLachlan, 1863, p. 159. Hydropsyche alternans — Hagen, 1861, p. 288. Hydropsyche alternans — McLachlan, 1863, p. 159. Hydropsyche slossonae var. recurvata Banks, 1914, p. 253, fig. 73, male: type locality. Go Home Bay, Ontario. Syn. Nimmo, 1981, p. 261. Hydropsyche codona Betten, 1934, p. 187, male, female. Syn. Ross, 1938b. Hydropsyche recurvata — Ross, 1938b, p. 18, lectotype male. Hydropsyche alternans — Betten and Mosely, 1940, pp. 20-21. Hydropsyche recurvata — Denning, 1943, pp. 126-127, fig. 16, allotype female. Hydropsyche recurvata — Ross, 1944, p. 99, figs. 16,344,357, larva; fig. 363'. male; figs. 387c, 388b, female. Symphitopsyche recurvata — Schuster and Etnier, 1978, pp. 34-35, larva. Hydropsyche recurvata — Smith and Lehmkuhl, 1980, pp. 621-633, figs. 5a, b, 9, 13. larva. Synonymy of Hydropsyche recurvata Banks with H. alternans (Walker) was established by Nimmo (1981) after examination of the female holotype of the latter. DIAGNOSIS A widely distributed checkerboard species, Hydropsyche alternans has a nearly square head capsule (ratio of length to width approx. 1.04). The smooth, nearly bare frontoclypeus with an exaggerated ridge at the tentorial pits separates this species from many checkerboard species, and H. alternans may be identified by the tp setae, usually clear and of uniform length, dorsaJly on the parietals, as well as by the presence of a dark seta 1 on the mesotrochanter. The variability of head capsule colour in H. alternans is typical of checkerboard species (Fig. 85), although dorsolateral light areas extending posteriad from the eyes to the frontoclypeal suture (Ross, 1944; Smith and Lehmkuhl, 1980) appear to be common to all populations; a population from Alaska contains individuals with unpatterned dark brown heads in which this area is only faintly visible. The posterior light area of the head capsule is not interrupted by dark pigment along the coronal suture. DESCRIPTION Head squarish, often with lateral margins convex, width 1.12-1.37 mm, length 1.21-1.45 mm (16 larvae). Frontoclypeus occasionally with very few erect//? setae posteriad of the tentorial ridge; the sclerite conspicuously ridged at the tentorial pits. Parietals with tp setae clear or occasionally dark, of uniform length, distally enlarged; ap and hi setae, if present, inconspicuous laterally, although occasionally con- spicuous ventrolaterally. Pronotum with anterolateral seta 22 long, dark, and tapered; dorsally and laterally with tp setae clear or dark; hi setae clear and inconspicuous. Mesonotum with seta 5 49 moderately long, clear; dorsally and laterally with tp setae clear, erect; hi setae dark, conspicuous. Metanotum with seta 5 moderately long, clear; dorsally and laterally withfy? setae clear, erect, sparsely scattered; hi setae numerous, dark, conspicuous. Procoxa variable; in addition to seta 1, mesolateral dark Is or si setae may be several, few, or none. Mesotrochanter with setae 1, 2, 3, and 5 long, dark, although seta 1 may be shorter than the other three; mesofemur with setae 3 and 4 long and dark, often with several dark Is setae between. Metatrochanter with setae 2 and 3 long and dark; metafemur with setae 3 and 4 long and dark. Erect abdominal sh setae shorter than adjacent hi setae and clavate. Venter of anal proleg with clear reddish or tan si setae basally, laterally, and on caudal lobes; some si setae may have prominent sockets similar to si setae on the ventral sclerite of abdominal segment IX; hi setae interspersed basally, laterally, and on caudal lobes. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 17-22; lateral branch, 20-26. BIOLOGY Hydropsyche alternans occurs in large, fast rivers, lake outflows, and along wave-washed lake shores. It is the only species in this group known to occur in lakes. RANGE Hydropsyche alternans has a northern transcontinental range, occurring from eastern Quebec westwards through Alberta, British Columbia, and the Yukon. Northern limits of the known range are the tree line around Hudson Bay in northern Quebec, Ontario, and Manitoba, to lat. 63°N in the Yukon. Southern limits are New England, New York, the southern shores of the Great Lakes, and southern Wisconsin, mid-Saskatchewan, and southern Alberta. METAMORPHOTYPES EXAMINED ALASKA: Glenn Highway, milepost 153 at Mendeltna Creek, 62°02'N by 146°42'W, 17 VII 82, #821124 (2 and larvae). ALBERTA: Battle River, at Highway 61 1 near junction with Highway 792, 15 VI 79 (4); Oldman River at Taber Provincial Park, 25-26 VII 70, #700442 (1 and larva). MANITOBA: Lake Winnipeg, at Gimli, 6 VI 81 (2 and 10 larvae); Lake Winnipegosis, along shoreline, 6 VIII 70, #700482 (3); Mistik Creek, ca. 46 km south of Flin Flon on Route 10, 30-31 VII 70, #700406 (10 and 100 larvae and pupae). MINNESOTA: Cook County, Saganaga Falls, 3 VIII 75 (2 and 1 larva). ONTARIO: Parry Sound District, Croft Township, Magnetawan River at Highway 124, Ahmic Harbour, 1 IX 72, #720458 (3 and 6 larvae); Thunder Bay District, Booth Township, Nipigon River, 3 VII 81 (4 and 15 larvae); Cedar Creek below dam, 6 VI 71, #710343 (1 and 20 larvae); Timiskaming District, Montreal River at Route 11, 27 VI 71, #710485 (7 and 70 larvae). QUEBEC: Montreal, lie Ste-Helene, 7 VI 65 (1). LARVAE AND ADULTS EXAMINED ALASKA: Mendeltna Creek, Glenn Highway, 30 VI 68 (6 adults). ALBERTA: St Mary River, at Highway 820 below reservoir, 12 VI 79 (1). ONTARIO: Algoma District, small stream at Route 17, 2.4 km east of Sowerby, 3 V 71, #710312 (4); Kenora District, Kiruna Lake, 27 VII 81, #810088 (adults and larvae); Lakitusaki River, 9 VI 77 (16); between McKenzie and Eva lakes, 27 VII 78 (7); Rushing River 50 Provincial Park. Rushing River. 13-14 VI 71. #710400 (6); Renfrew County. Waba Creek. 9 VI 54 (1); Thunder Bay District. Cedar Creek above dam, 6 VI 71. #710344 (adults); Lake St Joseph. Doran Outlet (25); Thelma Outlet (several; dates not available). QUEBEC: Rapide-Danseur, ca. 32.2 km south of Lac Abitibi. 27 III 63 (15); Schefferville. 18 VI 60 (1). SASKATCHEWAN: Cold Lake, Cold Lake beside street in town. 15 VIII 70, #700544 (30); Loon Lake, Makwa River, Fast-flowing outlet of Makwa Lake, 16 VIII 70, #700551 (1). YUKON: Alaska Highway, Morley River. 60°00'N by 132°08'W, IX 78 (1). Hydropsyche amblis Ross Hydropsyche amblis Ross, 1938c, p. 120, fig. 9, holotype male; type locality, Corvallis, Oregon. The larva of Hydropsyche amblis is associated here for the first time, with material from the state of Washington. DIAGNOSIS Among the species bearing numerous minute brushlike frontoclypeal setae, Hxdropsxche amblis and H. tana are the only dark brown larvae collected to date (Fig. 87). The brown parietal peg setae and clear, inconspicuous frontoclypeal bl setae distinguish H. amblis and H. tana from similar species, and H. amblis is distinguished from//, tana by the numerous bl setae giving the frontoclypeal sclerite a punctate appearance, in contrast to the smooth frontoclypeus with few bl setae characteristic of//, tana. DESCRIPTION Head nearly round, lateral margins convex; width 0.93-1.05 mm, length 1.10-1.13 mm (10 larvae). Frontoclypeus with bl setae numerous, clear, inconspicuous, on entire surface of sclerite; surface posteriad of tentorial ridge with wrinkled or punctate appearance. Parietals with clear bl setae dorsally, adjacent to coronal and posterior frontoclypeal sutures, mingled with a few brown tp setae; anteriorly tp setae inclined or erect, most numerous dorsad of eyes; few ap setae laterally; hi setae dark and conspicuous in lighter areas around eyes. Pronotum with anterolateral seta 22 dark, cylindrical, approximately two to four times longer than adjacent peg setae; dorsally and laterally with dark tp setae erect dorsally, inclined anteriorly on lateral surfaces; ap setae appressed; hi setae dark and conspicuous. Mesonotum with seta 5 dark, moderately long; dorsally and laterally with tp setae erect; ap setae few, appressed; hi setae dark, conspicuous. Metanotum with seta 5 moderately long, clear; dorsally and laterally with few erect tp setae; hi setae dark, conspicuous. Procoxa with seta 1 long, dark, occasionally with one or two dark si setae on same surface. Mesotrochanter with setae 2, 3, and 5 long, dark, occasionally with short, dark seta 1 present; mesofemur with setae 3 and 4 long, dark. Metatrochanter with seta 3 long, dark; seta 2 clear or not distinguishable; metafemur with seta 3 long, dark, seta 4 clear or not distinguishable. 51 Abdomen with erect sh setae shorter than adjacent hi setae and flattened. Venter of anal proleg with hi setae basally and laterally; there may be one or a few black si setae on lateral areas. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 8; lateral branch, 11-12. BIOLOGY Larvae of Hvdropsxche amblis were collected from Camp Creek, a second order tributary of the Cispus River, 35 km northeast of Mount St Helens in Washington; site "D" in the Mount St Helens ashfall study on lotic Trichoptera (Smith, 1981) is approximately 2 m wide and 0.3 m deep, with a mixed cobble bed, almost completely shaded by riparian forest. Beaver Creek, Wasco County, Oregon, is a similar stream. RANGE Hydropsyche amblis occurs in the coastal ranges of Washington, Oregon, British Columbia, and Alaska, and in the Yukon. METAMORPHOTYPES EXAMINED WASHINGTON: Jefferson County, Olympic National Park, small stream crossing readjust east of Hoh Valley Entrance, 29 VI 69, #690145 (7). YUKON: Atlin Road, km 12.5, Haunka Creek, 60°14'N by 133°53'W, 17 VI 82, #821055 (1 and 100 larvae). LARVAE EXAMINED OREGON: Benton County, St Marys Peak, small streams joining Woods Creek, 12 IV 64 (1); Wasco County, Beaver Creek at Route 26, 8 VI 84 (6 collected with 30 adults). WASHINGTON: Lewis County, near Randle, Camp Creek, #61 site. Mount St Helens Project, 16 V 81 (20). YUKON: Alaska Highway at Watson Lake Campground, small stream beside campground, 60°07'N by 128°48'W, 23 V 82, #821002(4). Hydropsyche bronta Ross Hydropsyche bronta Ross, 1938a, p. 149, fig. 79, holotype male, allotype female; type locality Bronson, Michigan, along Prairie River. Hydropsyche bronta — Denning, 1943, pp. 125-126, fig. 15, female. Hydropsyche bronta — Ross, 1944, p. 98, figs. 364,387b, male, female. Symphitopsyche bronta — Ross and Unzicker, 1977, pp. 304-305, type species of new subgenus Ceratopsyche, fig. 4, male. Symphitopsyche bronta — Schuster and Etnier, 1978, p. 25, fig. 19, Appalachian larval form; pp. 37-40, description of Central and Appalachian larvae. Hydropsyche bronta— Smith and Lehmkuhl, 1980, pp. 621-633, figs. 6,10, larva. Problems of confusion of this species with H. morosa are treated under the latter species. 52 DIAGNOSIS The checkerboard-patterned head of Hydropsyche bronta shows great variability of coloration within and between populations. Schuster and Etnier ( 1978) described two variants, the striped Appalachian form and the checkerboard Central form, indicating intermediate colour patterns had not been observed. Using setal characters one can discern H. bronta larvae with a variety of head colour patterns intermediate between Central and Appalachian forms. The head is narrow, the length approximately one and one-quarter times the width. The appressed ap setae near the lateral and posterior frontoclypeal angles, visible in light patches of the colour pattern on the frontoclypeus, will separate H. bronta from many other checkerboard species, and the larva may be identified by the few clear reddish si setae on the venter of the anal proleg, some of which have prominent sockets as stout as those of the si setae on the ventral sclerite of abdominal segment IX. The procoxa bears a single dark seta 1 mesolaterally, and the mesofemur usually bears dark setae 3 and 4 with no adjacent dark Is or si setae, although clear setae are often present. Variability of the head colour pattern in H. bronta includes the checkerboard pattern common to several morosa group species (Fig. 7 1 ) of seven light patches on a dark background, as well as intermediate combinations of contrasting light and dark patches. These include the distinctive striped Appalachian form (Fig. 73), larvae with a similar but less contrasted light and dark pattern (Fig. 76), and a light variant with little dark pigmentation (Fig. 72). Populations of the dark Central form seldom contain lighter variants, but populations of variant forms usually display a wide range of variability and may include a small proportion of darker larvae. DESCRIPTION Head width 0.94-1.18 mm, length 1.10-1.34 mm (34 larvae). Frontoclypeus with appressed ap setae near lateral and posterior angles. Parietals with ap setae of unequal lengths, usually dark (but they may be clear on light specimens), longer and more inclined anteriorly on lateral areas; tp setae erect, longer anteriorly, dark or clear as above, as fine as ap setae, cylindrical; appressed hi setae light, but visible. Pronotum with anterolateral seta 22 long, dark, tapered; dorsally and laterally with erect and inclined ap setae, few erect tp setae, and light hi setae. Mesonotum with seta 5 moderately long, clear; dorsally and laterally with appressed ap setae, erect tp setae of various lengths, and hi setae more numerous than on pronotum. Metanotum with seta 5 medium long, clear; dorsally and laterally with erect tp setae of various lengths, and hi setae dark and conspicuous. Procoxa with single dark seta 1 mesolaterally. Mesotrochanter with setae 2, 3, and 5 long, dark; several specimens have been observed to have a dark seta 1 on one or both mesotrochanters. Mesofemur with setae 3 and 4 long and dark. Metatrochanter with setae 2 and 3 long and dark; metafemur with setae 3 and 4 long and dark. Abdomen with erect sh setae clavate, similar in appearance to appressed hi setae. Ventral membranous area of anal proleg with a few clear reddish si setae on caudal lobe, mingled with a few short, fine hi setae. Basal reddish si setae with sockets as prominent as sockets of si setae on ventral sclerite of abdominal segment IX, also a few clear reddish si setae basally and laterally lacking prominent sockets; very few hi setae on lateral areas. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 9-11; lateral branch, 11-14. 53 BIOLOGY Although usually occurring in cooler upper reaches of streams, Hxdropsvche bronta is apparently tolerant of some organic enrichment. No correlation has been established between habitat and colour variation. H. bronta is often collected with//. slossonae, H. sparna, and//, morosa. RANGE Hydropsyche bronta occurs in the Appalachians from Quebec southwards through North Carolina, the range extending westwards to Alberta through southern Ontario, the midwestern States, to the south of Lakes Huron, Michigan and Superior. Northwestern limits are mid-Manitoba, mid-Saskatchewan, and mid- Alberta, and//. bronta extends into southeastern Wyoming to the south. A disjunct population occurs in the Ozark Plateau of Oklahoma and Arkansas. Appalachian, or striped, larvae occur over much of the range of H. bronta. Populations from Virginia, Tennessee, and North Carolina are distinct, with highly contrasting horizontal banding on the head and thoracic nota. Banded larvae with more muted colour differences, as well as intermediate forms between Appalachian and Central types, are recorded from New England and at least two areas of Ontario — the streams flowing southwards out of the extensive moraine area parallel to Lake Ontario in Northumberland and Hastings counties, and streams flowing north and west off the Niagara Escarpment in Grey County. A population of striped larvae is also recorded from the Black Hills in South Dakota and from central Alberta. Below, "var." designates variant forms — usually a light background with dark markings; no designation or "typ." indicates the typical checkerboard form. METAMORPHOTYPES EXAMINED ILLINOIS: Havana, Quiver Creek, 29 V 36, inhs (1); White Pine Park, 30 V 36, INHS (1). MARYLAND: Flintstone, 19 IV 38, INHS (1). NORTH CAROLINA: Avery County, Linville River at Linville Falls Campground, Blue Ridge Parkway, 22 V 70, #700369 (1 and 50 var. larvae). ONTARIO: Durham County, Duffin Creek at Greenwood Conservation Area, 22 V 80, #801007a (2 and 10 var., 10 typ. larvae); Halton County, Credit River, Glen Williams, 3 VI 75 (3); 3 VI 76 (1); Huron County, small stream at Huron County 12, 3.7 km south of Winthrop, 16 I 76 (7 and many typ. larvae); Northumberland County, Shelter Valley Creek at Highway 401, 26 V 76 (2 and 20 var. larvae); Peel County, Credit River at Churchville, 2 VI 52 (7); 1 1 VIII 76 (4 and 15 typ. larvae); Humber River at Albion Hills, 15 VII 75 (1); 8 V 76 (1); 12 V 76 (1); 6 VII 76 (1); Wellington/Grey counties, South Saugeen River at Highway 89, west of Mount Forest, 26 VII 76 (10 and 30 typ. larvae); North Spey River, Highway 10 south of Rock ford, 21 V 76 (1 and 6 var. larvae); York County, Humber River at Highway 27, 10 VI 76 (1). VIRGINIA: Montgomery County, Mill Creek at Route 785, 29 III 73 (1 var.); Roanoke County, Roanoke River at Virginia 419, 10 VII 76 (1 and 10 var. larvae). LARVAE EXAMINED ALBERTA: Little Red Deer River, at Highway 922 north of Highway 582, 23 VI 79 (15); Pembina Provincial Park, near Edson, 19 VII 61 (25); Highway 16, 16 VI 62 (15); Willow Creek, at Highway 527, 12 V 79 (12). ILLINOIS: Vermilion County, Jordan Creek 3.2 km southwest of Oakwood, 12 IV 83 (60). MANITOBA: Duck 54 Mountain Provincial Park, North Pine River at picnic grounds on 9th Baseline, 29 X 80, #801074 (1); Overflowing River, at provincial campground. Route 10. 4 VIII 70. #700481 (3); Riding Mountain National Park, Edwards Creek, 11 IV 62 (1). MARYLAND: Baltimore County, creek 3.2 km south of Jacksonville on Maryland 146. 5 IX 77 (1). NEW YORK: Cattaraugaus County, Allegheny River near Salamanca, 15 IV 68 (1); Tompkins County, Slaterville Springs, Six Mile Creek, 9 IX 66 (3). NORTH CAROLINA: Transylvania County. French Broad River at junction of 215N and 64E. 9 V 78, #780091 (3 var.). ONTARIO: Durham County, Duffin Creek at Greenwood Conservation Area, 3 VII 80, #801038 (6); Grey Count\ . Euphrasia/St Vincent Townline near Walters Falls, 27 VI 80 ( 1 var. , 1 typ.); Sydenham Township, Telford Creek, 8 VIII 79 (2); Saugeen River at Durham Conservation Area, 17 VI 76 (2 var., 2 typ.); 21 VI 76 (4 var., 2 typ.); Haldimand County, Grand River 4.8 km northeast of Grand Valley, 28 VII 60 (1); Huron County, Maitland River, 17 VI 76 (100); Middlesex County, Ausable River at Highway 81 south of Parkhill, 16 VI 76 (40); Thames River, 23 XI 66 (1); Nipissing District, Algonquin Park, Madawaska River at Highway 60, 29,31 V 72, #720203 (1); Northumberland County, small stream at Van Luven Road near Baltimore, 27 V 80, #801010 (1 ); Shelter Valley Creek, 1 1,20 VI 79, #790019 (2 var.); Peel County, Credit River at Forks of the Credit, 24 XI 78 (30); Humber River at Sideroad 25, Palgrave. 4 X 78 (10); 3 XI 78 (25); Simcoe County, stream at Highway 11, 15.8 km north of Highway 400 cutoff, 31 VIII 67 (2 var.); Victoria County, Manvers Township, Pigeon Creek, 11 VII 79 (4 var.); Wellington County, Shard Dam, Fergus, 27 VII 60 (3). TENNESSEE: Sevier County, stream at Tennessee 73, 14.5 km east of Gatlinburg, 3 X 67 (10 var.). VIRGINIA: Allegheny County, tributary of Jackson River beside Route 220 just north of Covington, 18 IV 68 (4 var.); Amherst County, Lower Otter Creek at Lower Otter Creek Overlook on Blue Ridge Parkway, 19 IV 68 (1 var.); Giles County, Sinking Creek, 23 V 74 (1 var.); Grayson County, Halton Creek, 4 IV 75 (1 var.); Highland County, Jackson River beside Route 84, 8 km southwest of Monterey, 5 X 67 (2 var.); Loudon County, Goose Creek at Route 7, 12 V 79 (1 var.); Montgomery County, Mill Creek at Route 785, 12 IV 79 (2 var.); Toms Creek, 19 IV 74 (1 var.). Hydropsyche centra Ross Hydropsyche centra Ross, 1938a, p. 150, fig. 82, holotype male, allotype female; type locality, Centralia, Washington. The type of Hydropsyche centra is similar to males of Palaearctic H. nevae Kolenati examined from Finland, Sweden, and Japan. Larvae of//, centra are associated with the adult and described here for the first time. DIAGNOSIS A checkerboard species apparently confined to the Pacific Northwest, Hydropsyche centra has a nearly square head capsule and a smooth, nearly bare frontoclypeus. //. centra can be distinguished from similar species by the lack of seta 1 on the mesotrochanter, and by the dark, distally enlarged tp setae of uniform length on the parietal sclerites. 55 DESCRIPTION Head width 1.16-1.29 mm, length 1.29-1.42 mm (three larvae); head nearly square, with lateral margins convex. Frontoclypeus with two to three erect tp setae near frontoclypeal sutures, and conspicuously ridged at the tentorial pits. Parietals with erect tp setae dark, of even length, distally enlarged, along frontoclypeal sutures; tp setae longer laterally; hi setae inconspicuous. Pronotum with anterolateral seta 22 moderately long, three to four times length of adjacent secondary peg setae, and tapered; dorsally and laterally with tp setae erect, dark, cylindrical or distally expanded; hi setae conspicuous on lateral surfaces. Mesonotum with seta 5 moderately long, clear; dorsally and laterally with tp setae tan, erect or inclined posteriorly; hi setae dark, conspicuous. Metanotum with seta 5 moderately long, clear; dorsally and laterally with tp setae clear tan, erect; hi setae dark, conspicuous. Procoxa with seta 1 long, dark; several dark si setae on mesolateral surface. Mesotrochanter with setae 2, 3, and 5 long and dark; on occasional specimens, a short, tan seta 1 may be present on one or both sides. Mesofemur with setae 3 and 4 long, dark, often with shorter, dark Is setae near seta 3. Metatrochanter with setae 2 and 3 long and dark; metafemur with setae 3 and 4 long and dark, or seta 4 occasionally clear. Abdomen with erect sh setae flattened, tan, mingled with appressed hi setae. Venter of anal proleg with si setae clear reddish, distributed basally and laterally, some with sockets obvious but less prominent than sockets of si setae on ventral sclerite of abdominal segment IX, mingled with dark hi setae. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 9-12; lateral branch, 14-16. BIOLOGY Habitat data are not available for Hydropsyche centra. RANGE Hydropsyche centra is confined to the Pacific coastal ranges from Oregon north to Vancouver Island and south-central British Columbia. METAMORPHOTYPES EXAMINED OREGON: Douglas County, Umpqua River south of Elkton on Route 138, 7 VI 68 (3 and 1 larva); 200 m above confluence of South Umpqua River and Cow Creek, 23 VII 76 (1). WASHINGTON: King County, Cedar Creek at Cedar Falls, 3 VI 72 (1). LARVAE EXAMINED OREGON: Douglas County, Cow Creek 200 m above confluence with South Umpqua River, 23 VII 76 (4); 22 X 76 (2); Elk Creek 6.4 km southeast of Tiller Bridge, 4 IX 75 (7); 5 IX 76 (3); South Umpqua River, 100 m upstream from Days Creek outflow, 5 IX 75 (6); 22 VII 76 (12); 22 X 76 (2); 1.6 km northwest of Canyonville, 5 IX 76 (3); 1 km south of Myrtle Creek outflow, 22 I 76 (1); 30 IV 76 (4); 23 VII 76 (5); 22 X 76 (2); 13 km northwest of Roseburg, Cleveland Rapids, 9 IX 75 (9); 30 IV 76 (1 1); 22 X 76 (13); 1 1 km northeast of Tiller Brook, 8 IX 75 (6); 17 km northeast of Tiller Brook, 2 IX 75 (7); 28 km northeast of Tiller Brook, 30 IV 76 (3); 22 X 76 (1 1); 2 km west of Tiller Brook, 23 VII 76 (8). All specimens mjs. 56 Hydropsyche cheilonis Ross Hydropsyche cheilonis Ross, 1938a, p. 149, fig. 80, holotype male, allotype female: type locality Oak wood, Illinois, along Salt Fork River. Hydropsxche cheilonis— Ross. 1944, pp. 98-99; figs. 284,291,293, larva; fig. 365. male; fig. 387d, female. Symphitopsyche cheilonis — Schuster and Etnier, 1978, p. 33, larva. Separation of this species from H. morosa is discussed under that species. DIAGNOSIS With a rectangular, checkerboard-patterned head, Hydropsyche cheilonis can be separated from many other checkerboard species on the basis of head shape and lack of apparent secondary setation on the frontoclypeus, although some populations include individuals with one or two dark, erect peg setae near the posterior frontoclypeal angle. The species is distinguished by the presence, basally and laterally on the venter of the anal proleg, of clear reddish, straight si setae, usually lacking prominent sockets. If sockets are present, they are less pronounced than sockets of si setae on the ventral sclerite of abdominal segment IX. DESCRIPTION Head width 0.97-1. 16 mm, length 1.13-1.34 mm (10 larvae). Frontoclypeus usually lacking apparent secondary setation on the surface posteriad of the tentorial ridge, although in some specimens one or two dark, erect peg setae may occur near the posterior frontoclypeal angle. Parietals with dark ap setae of unequal lengths, longer and more inclined anteriorly on lateral areas; also with dark or clear reddish tp setae of various lengths, longer anteriorly; appressed hi setae dark and conspicuous. Pronotum with anterolateral seta 22 dark, long and tapered; dorsally and laterally with numerous dark, erect and appressed ap setae, few erect tp setae, and dark, conspicuous hi setae. Mesonotum with seta 5 medium-long, clear, and fine; dorsally and laterally with ap setae appressed; tp setae erect, in greater numbers than on the pronotum; hi setae dark, conspicuous. Metanotum with seta 5 clear, short, and fine; dorsally and laterally with tp setae of various lengths, erect and inclined anteriorly, and inclined posteriorly; hi setae dark, conspicuous. Procoxa with single dark seta 1, short, clear and dark si setae adjacent. Mesotrochanter with setae 2, 3, and 5 dark. Mesofemur with several dark Is setae between dark setae 3 and 4; on some specimens there are one or more long, dark Is setae on the ventral margin of the femur. Metatrochanter with setae 2 and 3 long, dark; metafemur with seta 3 long, dark, seta 4 either dark or clear. Abdomen with erect sh setae clavate, similar to appressed hi setae. Ventral membranous area of anal proleg with clear reddish si setae basally and laterally, usually lacking prominent sockets, but if sockets are visible they are less pronounced than sockets of si setae on ventral sclerite of abdominal segment IX; hi setae most dense basally and on caudal lobes. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 11-14; lateral branch, 14-19. BIOLOGY Hydropsyche cheilonis occurs in warmer and more organically enriched streams than other species of the morosa group. 57 RANGE Hydropsyche cheilonis occurs in southeastern and south-central states, not extending farther north than Michigan, where its range may overlap with that of//, morosa. METAMORPHOTYPES EXAMINED OHIO: Ashland County, Clear Fork River at Mohican State Park southeast of Pleasant Hill Reservation, 2 VIII 68 (1 and 2 larvae). TENNESSEE: Knox County, Bull Run Creek on Tennessee 126 just south of Oak Ridge, 18 V 76, GAS. LARVAE EXAMINED ILLINOIS: Vermilion County, Jordan Creek 3.2 km southwest of Oakwood, 12 IV 83 (20); Muncie, 6 VII 36 (5): Oakwood, 14 VII 39 (2). Hydropsyche cockerelli Banks Hydropsyche cockerelli Banks, 1905, p. 14, pi. 1, figs. 8,9, male; type locality, Pecos, New Mexico. Hydropsyche cockerelli — Ross, 1938b, p. 16, fig. 34, lectotype male, lectoallotype female. Hydropsyche bicornuta Denning, 1965, p. 75, figs. 1,2, holotype male, allotype female; type locality, Klamath County, Oregon. Syn. Schefter, Wiggins, and Unzicker, 1986. Hydropsyche jewetti Denning, 1965, p. 78, fig. 6, holotype male; type locality, Glacier National Park, Montana. Syn. Schefter, Wiggins, and Unzicker, 1986. Symphitopsyche cockerelli — Alstad, 1980, p. 168, fig. 1, larva. DIAGNOSIS Hydropsyche cockerelli larvae have a variable checkerboard head colour pattern. With a smooth frontoclypeus, nearly bare of secondary setae and deeply ridged at the tentorial pits, H. cockerelli may be confused with H. alternans and H. centra where their ranges overlap. H. cockerelli sometimes lacks the dark seta 1 on the mesotrochanter which distinguishes H. alternans and bears dark tp setae on the parietal sclerites, in contrast to the clear tp setae of H. alternans. H. cockerelli usually bears a cluster of three or four dark Is setae between long, dark setae 3 and 4 on the mesofemur, while H. centra has one or two shorter Is setae in that position. Although H. cockerelli extends well into the northwestern range of//, alternans, where larvae probably occur together (adults of//, alternans and//, cockerelli were collected together by light trapping at the Yukon River in Whitehorse, the Yukon), //. alternans is not known to occur in the southern range of//, cockerelli. H. centra is apparently restricted to the moist coastal ranges of Oregon, Washington, and British Columbia, and perhaps does not overlap the ranges of//, alternans or H. cockerelli. Head colour variations include the basic checkerboard pattern as illustrated for//. alternans (Fig. 85), variants having increased light areas with pattern resembling striped (as in Fig. 74), or yellow heads with scant contrasting pigment (as in Fig. 82). 58 DESCRIPTION Head rectangular, rounded, lateral margins convex, width 1.21-1.37 mm, length [.37—1.50 mm (17 larvae). Frontoclypeus smooth with no obvious secondary setae, conspicuously ridged anteriad of tentorial pits. Parietals with tp setae erect, of uniform length, usually dark, either cylindrical or distally enlarged, with longer//? and up setae laterally; /;/ setae inconspicuous. Pronotum with anterolateral seta 22 moderately long (ca. four times length of adjacent peg setae), dark, and tapered; dorsally and laterally with tp setae dark, erect or inclined anteriorly; hi setae inconspicuous. Mesonotum with seta 5 moderately long, clear; dorsally and laterally with erect tp setae dark; hi setae pale but conspicuous. Metanotum with seta 5 clear, shorter than on mesonotum; dorsally and laterally with tp setae clear, erect or inclined posteriorly; hi setae dark, conspicuous. Procoxa variable, usually with moderately long seta 1 flanked by several dark Is and si setae. Mesotrochanter with setae 2, 3, and 5 long, dark; dark seta 1 usually present. Mesofemur with cluster of several dark Is setae between long, dark setae 3 and 4, although occasionally the long secondary setae may number only one or two. Metatrochanter with setae 2 and 3 long and dark; metafemur with setae 3 and 4 long and dark. Abdomen with erect sh setae flattened, mingled with appressed hi setae. Venter of anal prolegs with si setae clear reddish, some with prominent sockets and of varied stoutness, distributed basally, laterally, and on caudal lobes, mingled with dark hi setae. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 11-15; lateral branch, 14-18. BIOLOGY Hydropsyche cockerelli occurs mostly in the middle reaches of western montane streams with moderate gradient and cobble-boulder substrate and is often collected with H. uslari. Life history patterns and longitudinal distribution within the stream system are presented by Alstad (1980). RANGE Hxdropsyche cockerelli occurs mostly west of the continental divide in the Rocky Mountains from New Mexico to Alberta, and westwards to northern California, extending northwards to the Yukon. It has also been reported from Maine (Blickle and Morse, 1966), but this material should be re-examined in view of the range extension implied by the record. VIETAMORPHOTYPES EXAMINED COLORADO: Chaffee County, Arkansas River near Buena Vista, 9 VIII 73, SDS (2); Park County, South Platte River, ca. 16. 1 km south of Fairplay, 9 VIII 73, SDS (1). UTAH: Summit County, Provo River at Woodland, 2042.2 m, 24 VI 76 (2). Hydropsyche etnieri Schuster and Talak Hydropsyche etnieri Schuster and Talak, 1977, pp. 515-518; figs, la-3, holotype male; figs, lf-h, allotype female; type locality, Buffalo Springs, Tennessee. 59 Symphitopsyche etnieri — Schuster and Etnier, 1978, pp. 58-60, fig. 29, larva. DIAGNOSIS With a large, uniformly dark brown head capsule and frontoclypeus with few or no up or tp setae near the posterior corner, Hydropsyche etnieri is easily distinguished from other species having a short anterolateral pronotal seta 22. To date, H. etnieri has been collected only at the type locality, and no variability in colour pattern has been recorded. DESCRIPTION Head width 1.25-1.35 mm, length 1.40-1.50 mm (four larvae), sides parallel, appearing nearly square. Frontoclypeus with few or no ap setae near posterior corner; surface posteriad of tentorial ridge with distinctive wrinkled appearance. Parietals with numerous short, dark ap setae inclined anteriad, longer anteriorly; hi setae inconspicuous against darkly pigmented background. Pronotum with anterolateral seta 22 short and dark, tapered; dorsally and laterally with inclined ap setae, and hi setae inconspicuous on dark sclerite. Mesonotum with seta 5 short and dark; dorsally and laterally with erect and inclined ap setae, few erect tp setae, and hi setae conspicuous against lighter sclerite. Metanotum with seta 5 short and dark; dorsally and laterally with ap and tp setae in approximately equal numbers, and hi setae conspicuous. Procoxa with single long, dark seta 1 and several shorter, dark si setae adjacent. Mesotrochanter with setae 2, 3, and 5 long, dark; mesofemur with setae 3 and 4 long, dark, occasionally shorter Is setae between them. Metatrochanter with setae 2 and 3 long, dark; metafemur with seta 3 dark, seta 4 clear. Abdomen with erect sh setae slightly clavate, mingled with appressed hi setae. Venter of anal proleg with dark si setae mingled with hi setae basally and laterally. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 9-11; lateral branch, 12. BIOLOGY The type locality is a cold spring-fed creek with constant water temperature throughout the year. RANGE Hydropsyche etnieri is known only from Grainger County, Tennessee. METAMORPHOTYPES AND LARVAE EXAMINED TENNESSEE: Grainger County, Buffalo Springs Creek in Buffalo Springs on County Road 2479, 109.3 m west of junction of County Roads 2479 and 2480, 13 X 76 (6 paratypes and larvae). Hydropsyche macleodi Flint Hydropsyche macleodi Flint, 1965, p. 169, fig. 2, holotype male; type locality. Blue Ridge Parkway, Crabtree Meadows Campground, North Carolina. 60 Symphitopsyche macleodi — Schuster and Etnier, 1 978. pp. 30-51. fig. 25. larva. l)l\(,\OSIS Hydropsyche macleodi. with a reddish brown rectangular head capsule, is separated from most other species by its short anterolateral pronotal seta 22 and may be identified b\ the presence of numerous fine, inclined up setae scattered on the entire surface o\ the frontoclypeus. H venture also has numerous ap setae on the firontoclypeus, but they are concentrated on the posterior surface. These two closely related species are also distinguished on the basis of the number of gill filaments on abdominal segment III — H. macleodi has 4 to 6 filaments on the mesial branch, 5 to 6 on the lateral branch, while H. ventura has 5 to 7 mesiallv, 8 to 10 laterally on the bifid outer gill trunk. The erect abdominal sh setae in H. macleodi are slightly cla\ate, while the erect abdominal sh setae in H. ventura are flattened. The head capsule of H. macleodi is reddish brown with darker pigment on the triangular area posteriad of the tentorial ridge; head coloration in H. ventura is usually monochromatic dark brown. DESCRIPTION Head width 1.05-1.15 mm, length 1.15-1.30 mm (six larvae). Frontoclypeus with numerous dark or tan ap setae scattered over entire surface, best seen in dorsal view. Panetals with ap setae erect, dark or tan. longer laterally and anteriorly; hi setae conspicuous. Pronotum with anterolateral seta 22 short and slightly tapered; dorsally and laterally with a/? setae erect, dark or tan;/?/ setae conspicuous. Mesonotum with clear, inconspicuous seta 5; dorsally and laterally with ap setae erect, tan, few erect tp setae, and /;/ setae conspicuous. Metanotum with clear, inconspicuous seta 5; dorsally and laterally with tp setae erect, translucent, and hi setae conspicuous. Procoxa with dark seta 1 sometimes accompanied by dark Is setae; several short, dark 5/ setae adjacent. Mesotrochanter with setae 2, 3, and 5 long, dark; mesofemur with setae 3 and 4 long, dark, often with dark Is setae between. Metatrochanter with seta 3 long and dark, seta 2 clear or not distinguishable; metafemur with seta 3 long and dark; seta 4 clear or not distinguishable. Abdomen with erect sh setae clavate, mingled with appressed hi setae. Venter of anal proleg with hi setae basally and laterally, and a few tan si setae on lateral areas. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 4-6; lateral branch, 5-6. BIOI.()(,\ H\drops\che macleodi is restricted to cold-water habitats, occurring in brooks and spring-fed permanent streams. RWGE Hydropsyche macleodi occurs in the Appalachian Mountains of Georgia, North Carolina, Tennessee, West Virginia, and Virginia. ME I AMORPHOTYPES EXAMINED None available. 61 LARVAE EXAMINED NORTH CAROLINA: McDowell County, Pisgah National Forest, South Toe River at Black Mountain Campground, 23 X 84, #840235 (6); Great Smoky Mountains National Park, Couches Creek at Route 441, 2 X 67 (15). TENNESSEE: Great Smoky Mountains National Park, west fork of Pigeon River at Chimneys Campground, 3 X 67 (20); Sevier County, unnamed stream, east slope of Webb Mountain off Tennessee 73, east of Gatlinburg, 24 I 75 (6). WEST VIRGINIA: Tucker County, unnamed stream 8 km south of Davis on Route 32, 30 V 84, #840108 (1). Hydropsyche morosa Hagen Hydropsyche morosa Hagen, 1861, p. 287, male; type locality, St Lawrence River, Canada. Hydropsyche chlorotica Hagen, 1861. Syn. Ross, 1938c. Hydropsyche bifida Banks, 1905, p. 15, male, female; type locality. Fort Collins, Colorado. Syn. Schefter and Unzicker, 1984. Hydropsyche morosa — Ross, 1938b, p. 16, pi. 4, fig. 33, lectotype male. Hydropsyche bifida — Ross, 1938b, p. 16, fig. 32, lectotype male, lectoallotype female. Hydropsyche morosa — Denning, 1943, pp. 127-129, pi. 20, fig. 17, allotype female. Hydropsyche bifida — Denning, 1943, pp. 129-131; fig. 18, female; fig. 19, pupa. Hydropsyche morosa — Ross, 1944, pp. 91,96,98; fig. 366, male; fig. 387e, female. Hydropsyche bifida— Ross, 1944, p. 97, figs. 356,384a,388a,367,387i, male, female, larva. Hydropsyche morosa — Mackay, 1978, pp. 499-509, figs. 5a, 6c, larva. Symphitopsyche morosa — Schuster and Etnier, 1978, pp. 41-43, fig. 20, larva. Symphitopsyche bifida — Schuster and Etnier, 1978, pp. 25,30, fig. 17, larva. Hydropsyche bifida — Smith and Lehmkuhl, 1980, pp. 621-633, figs. 1,2,8,11,14, larva. Hvdropsvche morosa — Schefter and Unzicker, 1984, figs. 1-5, male; fig. 6, female; figs. 7,8, larva. While processing adult material from many parts of the North American continent, we were able to discern two distinct forms of Hydropsyche morosa, which are herein treated as H. morosa east (formerly H. morosa) and H. morosa west/central (formerly H. bifida), as well as intermediate forms occurring primarily in north-central areas of North America from eastern Saskatchewan eastwards to Quebec, and into western New York, Michigan, Wisconsin, and Minnesota. This 62 complex was recently synonymi/.ed under//, morosa (Schefter and Unzicker, 1984). Larvae also occur in distinct forms as well as with a mixture of characters, and although the larval form is not always associated with the corresponding adult form, in general larvae of the west/central form are associated with adults previously identified as H. bifida and those of the eastern form with H. morosa. H. morosa larvae not easily assigned to either form occur in many populations, however, and are not necessarily associated with adults of intermediate genitalic characteristics. Separate diagnoses are given for larval populations associated with eastern and west/central adults and remarks include comments on chaetotaxal and colour characters which may be variable. DIAGNOSIS Hydropsyche morosa east may be confused with H. bronta where their ranges overlap, but H. morosa can usually be distinguished by the morphology of the clear reddish or tan si setae located both basally and laterally on the venter of the ana] proleg; on those with prominent sockets, the sockets are less pronounced than the sockets of the si setae of the ventral sclerite of abdominal segment IX. Setation of the procoxa, mesofemur, and metafemur also distinguishes H. morosa east and H. bronta. The checkerboard head colour pattern of//, morosa east is more variable than previously described, and the posterior angle of the frontoclypeus may have three small light spots as described by Schuster and Etnier (1978), a single large posterior light patch, a large and a small patch, or be completely lacking a light spot in that area. The basic head pattern may be dark brown with light spots (Fig. 77) or yellow with light spots in a dark triangle posteriad of the tentorial ridge (Fig. 79); usually dark pigment suffuses the coronal suture. H. morosa west/central may be confused with//, cheilonis if their ranges overlap in the Midwest. H. morosa west/central larvae are extremely variable in some populations in this area; H. morosa west/central larvae lacking appressed ap setae near the frontoclypeal suture, described by Smith and Lehmkuhl (1980) as//, bifida, have also been observed in North Dakota populations. These larvae will key to //. cheilonis. Conversely, larvae from Virginia which are presumably//, cheilonis may key to H. morosa west/central, which is not known southeast of the Great Lakes. Further study of associated material from areas of possible overlap may yield new characters to reliably separate the two species. The checkerboard head pattern of//. morosa west/central is most frequently variable in the posterior frontoclypeal angle where three, one, or no light patches may be present (as in Figs. 71,77-79). Intermediate larval forms vary in primary setation of the metafemur, morphology of the erect abdominal sh setae, and occurrence of appressed ap setae on the frontoclypeus. DESCRIPTION H. morosa east. Head rectangular, lateral margins parallel, width 1.05-1.21 mm, length 1.27-1.45 mm (10 larvae). Frontoclypeus with dark, appressed ap setae posteriad of tentorial ridge, few or numerous, usually visible in light areas of frontoclypeal pattern; on specimens with mostly yellow heads the dark ap setae are easily seen, but on individuals with very dark coloration and lacking posterior light patches, the setae may only be visible when viewed in profile. Parietals with dark, erect ap setae of unequal lengths, more appressed laterally; dark, erect tp setae of 63 various lengths, longer anteriorly; hi setae conspicuous in lighter areas of head pattern. Pronotum with anterolateral seta 22 long and dark; dorsally and laterally with ap setae dark, inclined; tp setae dark, erect; hi setae conspicuous. Mesonotum with seta 5 moderately long, dark; dorsally with ap setae dark or clear, appressed; tp setae dark or clear, erect or inclined posteriorly; hi setae conspicuous. Metanotum with seta 5 moderately long and dark; dorsally and laterally with tp setae short, erect and inclined; hi setae conspicuous. Procoxa with dark seta 1 sometimes flanked by dark Is seta; several short, clear and dark si setae on same surface. Mesotrochanter with setae 2, 3, and 5 long, dark; mesofemur with setae 3 and 4 long, dark, often several dark Is setae between. Metatrochanter with setae 2 and 3 long, dark; metafemur with seta 3 long, dark, seta 4 clear, or occasionally dark. Abdomen with erect sh setae clavate, mingled with appressed hi setae. Venter of anal proleg with clear reddish or tan si setae basally and laterally, some with prominent sockets less pronounced than sockets of si setae on ventral sclerite of abdominal segment IX; hi setae distributed basally and laterally. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 12-16; lateral branch, 14-17. H. morosa west/central. Head rectangular, width 0.97-1.18 mm, length 1.10-1.34 mm (32 larvae), lateral margins parallel or slightly divergent posteriorly. Frontoclypeus usually with few dark, appressed ap setae posteriad of the tentorial ridge, sometimes visible in light areas of head pattern, although occasional populations may lack this setation. Parietals with dark, erect ap setae of uneven lengths, more inclined laterally; dark, erect tp setae of various lengths, longer dorsad of the eyes; hi setae inconspicuous. Pronotum with anterolateral seta 22 long, dark, tapered; dorsally and laterally with ap setae dark, inclined; tp setae dark, erect; /;/ setae conspicuous. Mesonotum with seta 5 moderately long, dark; dorsally and laterally with tp setae dark, erect; ap setae clear tan, inclined anteriorly; hi setae conspicuous. Metanotum with seta 5 moderately long, clear; erect tp setae dark, inclined tp setae clear; hi setae conspicuous. Procoxa with dark seta 1 flanked by one or two dark Is or si setae. Mesotrochanter with long, dark setae 2, 3, and 5; mesofemur with setae 3 and 4 long, dark, often with shorter Is setae near seta 3. Metatrochanter with setae 2 and 3 long, dark; metafemur usually with setae 3 and 4 long, dark (seta 4 may be clear or not distinguishable). Abdomen with erect sh setae flattened, mingled with appressed hi setae. Venter of anal prolegs with clear reddish or tan si setae on caudal lobes, basally, and laterally, the sockets usually less prominent than sockets of si setae on ventral sclerite of abdominal segment IX; hi setae distributed basally and laterally. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 17-22; lateral branch, 18-22. BIOLOGY Hydropsyche morosa east occurs in upper and middle reaches of streams and small rivers, showing a moderate range of tolerance to temperature and organic enrichment; it is frequently collected with H. bronta, H. sparna, and H. walkeri. H. morosa 64 west/central populations have been found in lake outflows and culvert discharges laden with organic material, as well as in large rivers such as the Niagara (New York). Fox (Wisconsin), and St Lawrence (Quebec). Adults emerging in abundance from large rivers may be an annoyance to nearby residents, as the minute hairs on the insects' bodies and wings are easily dislodged, suspended in the air, and when inhaled may induce an allergic reaction (Osgood, 1934, 1957). As well, sheer numbers of insects flying and perishing are a nuisance. Several attempts at control have been conducted at Fort Erie, Ontario (Peterson, 1952) and lie Ste-Helene, Quebec (Fredeen. 1971). RANGE Hydropsyche morosa east occurs from eastern Quebec and Nova Scotia in the east, to its western limit in North Dakota. It has been recorded to the tree line in northern Quebec, is widespread in southern Quebec and southern Ontario, but occurs locally in northern Ontario. The southern range limits are Georgia in the Appalachian Mountains, the southern perimeter of the Great Lakes through Wisconsin, and northern Minnesota. The west/central form of H. morosa occurs from Quebec in the east to Vancouver Island, British Columbia, in the west. This form does not occur south of New England in the Appalachians, occurs locally in Ontario, and is most common in the north-central states and provinces. Intermediate forms occur in disjunct populations in a broad east-west band extending from Saskatchewan eastwards to Quebec, and are prevalent in northern Ontario, and the Niagara and St Lawrence river basins. METAMORPHOTYPES EXAMINED H. morosa east. MINNESOTA: Cook County, Temperance River at U.S. 61, 21 VII 75, GAS (5 and 20 larvae). NEW YORK: Delaware County, Beaverkill River at Exit 92, Route 17, 27 VII 81, #81 1 100 (4 from larvae reared in lab, emerged 11 VIII 81 ff.). ONTARIO: Durham County, Duffin Creek at Greenwood Conservation Area, 1 1 VII 79, #790026 (1 and 40 larvae); 3 VII 80, #801038 (1 and 8 larvae); Grey County, Beaver River at Clarksburg, 21 V 76 (10 and 10 larvae); 17 VI 76 (5 and 20 larvae); 26 VI 76 (3 and 6 larvae); 29 VII 76 ( 10 and 30 larvae); South Saugeen River at Highway 89 west of Mount Forest, 20 V 76 ( 10 and 30 larvae); 29 VII 76 ( 1 and 10 larvae); Halton County, Glen Williams, Credit River, 10 VI 52 (3 and 2 larvae); Norval, Credit River, 30 IV 73 (2 and 10 larvae); Hastings County, Moira River, at Highway 401, 15 VIII 76 (2); 14 VI 79, #790016(1 and 1 larva); at Latta, 6 VI 75 (8 and 15 larvae); 13 VI 76 (3 and 10 larvae); Nipissing District, Algonquin Park, Oxtongue River, Tea Lake Dam, 5 VII 54 (4 and 16 larvae); 15 IX 60; Northumberland County, Ganaraska River, 15 VIII 76 (1 and 100 larvae); 31 VII 79; Shelter Valley Creek at Highway 401, 26 V 76 (5 and 10 larvae); 13 VI 76 (5 and 20 larvae); 1 1 VI 79, #790012 (8); 20 VI 79, #790019 (2 and 50 larvae); Parry Sound District, Cashman Creek at Highway 518 at Sand Lake, 1 VI 72, #720212 (1 and 2 larvae); Peel County, Credit River, Churchville, 3 VI 76 (1); 29 VI 76 (1); 1 1 VIII 76 (8 and 30 larvae); Forks of the Credit, 2 VI 76 (1); Erindale, 21 V 71 (7 and 50 larvae); 3 VI 76 ( 1); 15 VI 76 (2); 11 VIII 76 (6 and 20 larvae); Simcoe County, Humber River, Rowntree Mills, 25 V 76 (2); 10 VI 76 (1); York County, Humber River at Highway 27, 10 VI 76 (1). TENNESSEE: Blount County, Little River 9.2 km northwest of Townsend at Tennessee 73, 15 IV 78, #780068 (7). VIRGINIA: 65 Bedford County, James River at Peter's Creek on Virginia 501, 30 VIII 76, inhs (1 and 13 larvae). H. morosa west/central. BRITISH COLUMBIA: Burnaby, 11 VII 46, INHS (2). ILLINOIS: Rock River, south fork at U.S. 51 south of Rockford, 25 VIII 76, GAS (4 and 15 larvae). MANITOBA: Roseau River, 2 km downstream from Highway 59, south of Rosa, 27 V 81 , #81 1072a (2 and 30 larvae). MINNESOTA: Carver County, Watertown, Crow River, 27 VIII 75, GAS (1); Chisago County, Sunrise River at Minnesota 95, 6 VII 76, GAS (4 and 10 larvae); Clearwater County, Itasca State Park, Mississippi River, culvert under road, 1 VI 81, #81 1086 (1 and 40 larvae); Hubbard County, Park Rapids, Fishhook River, 31 V 81, #811082a,b (1 and 20 larvae). NORTH DAKOTA: Pembina County, Icelandic State Park, Ren wick Lake and Tongue River at Renwick Dam, 9.7 km west of Cavalier on Route 5, 8 VII 81, #813013b (20 and larvae collected with adults). ONTARIO: Kenora District, Rushing River Provincial Park, outlet at Dogtooth Lake, 6 VII 81, #813012a (5 and adults); Rushing River, 13-14 VI 71, #710400 (2 and 3 larvae); Lake Saganaga, Northern Light Rapids, 15 VIII 75, GAS (6). Hydropsyche oslari Banks Hydropsyche oslari Banks, 1905, p. 13, fig. 2, male; type locality, southwest Colorado. Hydropsyche partita Banks, 1914, p. 252. Syn. Ross, 1938b. Hydropsyche oslari — Ross, 1938b, p. 18, fig. 35, lectotype male, lectoallotype female. Hydropsyche oslari — Flint and Herrmann, 1976, pp. 894-898. Hydropsyche oslari — Haddock, 1977, pp. 169-174, fig. 1. Symphitopsyche oslari — Alstad, 1980, p. 168, fig. 1, larva. Larvae which key to Hydropsyche oslari may show variability in setal morphology on the head and dorsum of the abdomen. Examination of adult material, particularly from Oregon, Washington, and British Columbia, has revealed variability in male and female genitalic characters which suggests that a complex of closely related species may exist in this area. DIAGNOSIS Widespread in the Rocky Mountains and westwards, Hvdropsyche oslari is easily separated from other known noncheckerboard western species. In H. oslari the frontoclypeus may have a few tp setae posteriad of the tentorial ridge or may appear slightly pebbled, while other species have either black head setae or numerous short hi setae on the entire surface of the frontoclypeus. The head appears nearly round in dorsal aspect, the lateral margins convex, with clear, short tp setae of even length on the parietals. H. oslari is variable in coloration, the head ranging from dark brown to yellow, either possessing or lacking a light median area anteriad of the tentorial ridge (Fig. 86). 66 DESCRIPTION Head width 1.13-1.29 mm, length 1.16-1.40 mm (29 larvae). Frontoclypeus may appear pebbled, be devoid of setae, or have a few tp setae near frontoclypeal suture postenad of tentorial ridge. Parietals with ereet, clear or occasionally dark tp setae of uniform length dorsallv. longer anteriorly; clears/; setae laterally and ventrolateral^ . In one population examined, sharp, curved, appressed hi setae occur laterally in the posterior parietal setal area. On specimens with darker head setation, hi setae may be dark and conspicuous on parietals. PYonotum with anterolateral seta 22 moderately long, dark, and tapered, but may be blunt apically; the anterolateral margin bears several conspicuous, curved peg setae, longer and thicker than the dorsal and lateral peg setae, but shorter than seta 22; dorsaJly and laterally with//? setae erect, clear;/?/ setae conspicuous. Specimens with sharp, curved, appressed hi setae on the parietals may have this type of seta laterally on the pronotum. Mesonotum with seta 5 moderately long, clear, apically blunt; dorsally and laterally with/p setae clear, erect; occasionally with a few appressed ap setae; hi setae conspicuous. Metanotum with seta 5 moderately long, clear, and apically blunt; dorsaJly and laterally with clear, erect tp setae; hi setae conspicuous. Procoxa with single long, dark seta 1, several shorter, dark si setae adjacent. Mesotrochanter with setae 2, 3, and 5 long, dark, occasionally a short, dark seta 1 present; mesofemur with setae 3 and 4 long, dark, often with dark si and Is setae between them. Metatrochanter with seta 3 dark, seta 2 clear (an occasional individual may have light setae in both positions); metafemur with seta 3 dark, seta 4 clear or not distinguishable. Abdomen with erect sh setae clavate or occasionally flattened, mingled with appressed/// setae. Venter of anal proleg with dark si setae laterally, hi setae laterally, basally, and on caudal lobes. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 9-13; lateral branch, 14-15. BIOLOGY Hydropsxche oslari is widespread throughout the western United States and Canada, occurring mostly in the middle reaches of streams and small rivers. A detailed description of a spring-fed habitat, where H. oslari occurs with Ochrotrichia susanae , was given by Flint and Herrmann (1976). Alstad (1980) described life history and longitudinal distribution of//, oslari in some Utah streams. RANGE Hydropsxche oslari occurs mostly to the west of the continental divide in the Rocky Mountains and coastal ranges from Baja California northwards into the Yukon, the range extending eastwards into central Alberta and North Dakota. METAMORPHOTYPES EXAMINED BRITISH COLUMBIA: Koksilah River, at road to Port Renfrew 3.7 km west of Shawnigan Lake, 28 VI 69, #690137 (3). CALIFORNIA: Alpine County, West Carson River, Route 89, 3.2 km west of Woodfords (1828.8 m), 19 VI 73, SDS (2 and 3 larvae); Marin County, Lagunitas, 7 VI 61 (1); Mariposa County, Wawona (1219.2 m), 17 VII 46 (3); Mono County, Convict Creek, 14 VII 66 (6 and 6 larvae); Mammoth Creek at Route 395, 61.2 km north of Bishop, 16 VII 66 (2 and 2 prepupae); Santa Cruz County, San Lorenzo Creek, 4 km west of Santa Cruz, 12 VII 67 73, SDS (2); Sequoia National Park, creek at Dorst Creek Campground, 22 VI 61 (1); Sierra County, Fiddle Creek, 19.3 km west of Downieville, 26 VI 73, SDS (2); Siskiyou County, Walker Creek, 17 VI 73, SDS (1); Tehama County, Guernsey Creek 3.2 km south of Childs Meadow, 27 VI 73, SDS (2); Tuolumne County. Sheering Creek 3.2 km south of Pinecrest, 18 VII 73, SDS (1). COLORADO: Chaffee County, Arkansas River, 6.4 km north of Buena Vista, 9 VIII 73, SDS (1); Jefferson County, Bear Creek at Corwina Park (2057.4 m), 27 VI 81 , DER ( 1 and 3 larvae); at Evergreen Lake Inlet (2155.5 m), 20 VI 81, DER (1); Park County, South Platte River ca. 16 km south of Fairplay, 9 VIII 73, SDS (1). IDAHO: Idaho County, small stream at Route 12 between Holly and Stanley creeks northeast of Lowell, 24 VI 68 (10 and 20 larvae). OREGON: Benton County, north fork of Alsea River at Route 34 east of Alsea, 6 VI 68 (10); Grant County, small creek at Dale Ranger Station, 40.2 km north of Long Creek, 7 VII 74, SDS (1); Lane County, Elk Creek 2.7 km west of Blue River, Route 126, 22 VII 74, SDS (1); Lincoln County, stream along Trenholm Saddle Road, Route 34 east of Tidewater, 15 VI 67 (3); Linn County, Quartzville Creek ca. 2.6 km east of Yellowstone Guard Station, Quartzville Road, 17 VI 68 (2 and 10 pupae). UTAH: Uintah County, Green River at Green River Campground, Dinosaur National Monument, 29 VII 66 (4 and 50 larvae). WASHINGTON: Klickitat County, Klickitat River, 8 VII 74, SDS (1). WYOMING: Fremont County, Crowheart, stream at Route 287, 28 VI 68 (5 and prepupae). Hydropsyche piatrix Ross Hydropsyche piatrix Ross, 1938a, p. 148, fig. 77, holotype male; type locality, Greer, Missouri. Hydropsyche piatrix — Ross, 1944, p. 97, fig. 360, male; fig. 387h, allotype female. Symphitopsyche piatrix — Schuster and Etnier, 1978, pp. 57,58, fig. 28, presumed larva. Larvae of Hydropsyche piatrix are associated with the adult for the first time from the outflow of Mammoth Spring in Mammoth Spring, Arkansas. The larva is the same as that presumed by Schuster and Etnier (1978) to be H. piatrix. Larvae were collected from Greer Spring, Missouri, and Turner's Mill Spring, near Greer, where we collected several adults by light trapping and sweeping. DIAGNOSIS Although having checkerboard coloration on the head, Hydropsyche piatrix is readily distinguished from similar species by the red si setae on the ventral membranous area of the anal prolegs, which have prominent sockets considerably more enlarged and darker red than the sockets of the si setae of the ventral sclerite of abdominal segment IX, and by the very short, clear, inclined ap setae on the parietals. DESCRIPTION Head rectangular, width 1.05-1.10 mm, length 1.25-1.30 mm (two larvae). Frontoclypeus lacking apparent setation except near anterolateral corners. Parietals with very short, clear, inclined ap setae; hi setae clear, inconspicuous. 68 Pionotum \\ ith anterolateral seta 22 long, dark, tapered; dorsally and laterally with elear, inconNpicuous up setae and /;/ setae. Mesonotum with seta 5 dark, tapered, and moderately long; dorsally and laterally with ap setae short, elear, inelined; tp setae few, clear, inconspicuous; hi setae dark, conspicuous. Metanotum with seta 5 clear, moderate!) short, blunt; dorsally and laterally with//? setae elear and inconspicuous; hi setae dark and conspicuous. Procoxa with single long, dark seta 1. Mesotrochanter with setae 2, 3, and 5 long, dark; on one specimen, dark seta 1 present on one side. Mesofemur with setae 3 and 4 long. dark, occasionally shorter Is setae between. Metatrochanter with setae 2 and 3 long, dark; on one specimen, dark seta 1 present on one side; metatrochanter missing or damaged on other specimen. Metafemur with setae 3 and 4 long, dark. Abdomen with erect sh setae clavate, similar in morphology to appressed/;/ setae; abdominal seta 5 especially dark and conspicuous. Venter of anal prolegs with stout, clear, red, curved si setae with prominent sockets on basal area — the sockets more pronounced than on si setae on ventral sclerite of abdominal segment IX; thinner, straighler i7 setae laterally; few hi setae basally and on caudal lobes. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 12-13; lateral branch, 16-18. The H. piatrix individuals examined showed no variability of the checkerboard head pattern. BIOLOGY Metamorphotypes of Hxdropsxche piatrix were collected from the outflow of Mammoth Spring, in Mammoth Spring, Arkansas, in early October. Many adults were present on riparian vegetation. Larvae of//, piatrix were collected in May from Greer Spring and Turner's Mill Spring, Missouri. Greer Spring (16°C.) is a large headwater source of Eleven Point River, and Turner's Mill Spring (13.9°C.) is a smaller spring-fed tributary of the same river. The larvae were on small and medium-sized rocks in shallow areas of both streams, within 200 m of the upwelling or outflow source. Adults were collected in May by light from Eleven Point River, 0.4 km downstream from the inflow of Greer Spring. RANGE Hxdropsxche piatrix is apparently restricted to spring-fed streams of south-central Missouri and north-central Arkansas. Schuster and Etnier (1978) believe the only other record (Corbet, Schmid, and Augustin, 1966, from the St Lawrence River in Quebec) to be a misidentification of a closely related species. METAMORPHOTYPES EXAMINED ARKANSAS: Fulton County, downstream from Mammoth Spring, between dam and junction with Spring River, 4 X 84, #840207 (5). LARVAE EXAMINED ARKANSAS: Fulton County, downstream from Mammoth Spring, 43.7 m north of junction with Spring River in Mammoth Spring (just east of Route 63 crossing), 25 IX 76 (2). MISSOURI: Oregon County, Mark Twain National Forest, Greer Spring, major headwater source of Eleven Point River, off Route 19 ca. 1.5 km south of Eleven Point River bridge, 5 V 84, #840004 (40); Mark Twain National Forest, 69 Turner's Mill Spring, small tributary of Eleven Point River in Turner's Mill Recreational Area, off Route 19 ca. 8 km north of Eleven Point River bridge, 5 V 84, #840005 (15). Hydropsyche slossonae Banks Hydropsyche slossonae Banks, 1905, p. 14, figs. 4,7, male, female; type locality, Franconia, New Hampshire. Hydropsyche slossonae — Ross, 1938b, p. 18, fig. 30, lectotype male, lectoallotype female. Hydropsyche slossonae — Denning, 1943, pp. 131-133, fig. 20, female; fig. 21, pupa. Hydropsyche slossonae — Ross, 1944, p. 99, figs. 16,355, larva; fig. 362, male; fig. 387g, female. Hydropsyche slossonae — Mackay, 1978, pp. 499-509, fig. 4a, 5a, 6a, b, larva. Symphitopsyche slossonae — Schuster and Etnier, 1978, pp. 47-50, figs. 23,24, larva. DIAGNOSIS Widespread in cool, unpolluted streams in much of northern North America, Hydropsyche slossonae is easily identified even though variable in colour. Colour patterns of the head range from uniformly dark brown through the most frequently encountered median- spotted varieties (Ross, 1944; Mackay, 1978; Schuster and Etnier, 1978), and in localized populations colour patterns may resemble checkerboard species or even be solid yellow. With the exception of a few H. aenigma specimens no other eastern or northeastern species exhibits the dark head pattern commonly seen in//, slossonae (with one, two, or three median light spots), but H. slossonae larvae with other markings may be easily identified by the long, dark hi and si setae on the venter of the anal prolegs, the cluster of long, dark Is setae between setae 3 and 4 on the mesofemur, the presence of numerous dark ap parietal setae, and the presence on the metafemur of a long, dark seta 4. Head colour can be variable as described above (Figs. 80-82), but the posterior area of the head (from the posterior frontoclypeal angle posteriad) is invariably light, without intrusion of dark pigment along the coronal suture. DESCRIPTION Head rectangular, width 1.02-1.32 mm, length 1.19-1.53 mm (16 larvae). Frontoclypeus lacking apparent setation other than at anterolateral corners, although on some yellow individuals one or two erect, dark ap setae may occur near the frontoclypeal sutures. Parietals with ap setae numerous, erect, very dark, longer laterally and anteriorly; lateral parietal ap setae are appressed and may be lighter in colour; hi setae dark and conspicuous. Pronotum with anterolateral seta 22 long, dark, tapered; dorsally and laterally with ap setae dark, erect and inclined; tp setae few, erect, longer than surrounding ap setae; hi setae dark, conspicuous. Mesonotum with seta 5 moderately long, light tan; dorsally and laterally with ap setae erect, dark; tp setae few, longer than ap setae; hi 70 setae dark, conspicuous. Metanotum with seta 5 short, light tan; dorsally and laterally with tp setae dark, short, and erect, and long and inclined posteriorly; hi setae conspicuous. Procoxa with single long, dark seta 1, several short, dark si setae adjacent. Mesotrochanter with long, dark setae 2, 3, and 5; mesofemur with cluster of long, dark Is setae between long, dark setae 3 and 4. Metatrochanter with setae 2 and 3 long, dark; metafemur with seta 3 long, dark, seta 4 usually dark, but occasionally clear. Erect abdominal sh setae clavate, mingled with appressed hi setae. Venter of anal prolegs with/;/ setae and sharp, darks/ setae of the same length basaJly, laterally, and on caudal lobes. Individuals may have one or a very few fine, translucent or tan si setae basaJly or laterally. Gill filaments on outer bifid trunk of abdominal segment III; mesial branch, 11-13; lateral branch, 14-16. BIOLOGY Hxdropssche slossonae occurs in cool, unpolluted streams (for life history patterns, see Mackay, 1979), although the larvae are tolerant of some sediment and organic enrichment. The species is frequently collected with H. bronta, H. alhedra, or H. spama . RANGE Hydropsyche slossonae is widely distributed in eastern North America, occurring in the Maritime Provinces, eastern Quebec, and southwards through the Appalachian Mountains from New England to South Carolina. The tree line around Hudson Bay in Quebec and Ontario is the northeastern limit of distribution. Widespread north and south of the Great Lakes, H. slossonae extends westwards through south and central Manitoba and Saskatchewan to British Columbia and southwards to Colorado. A disjunct population exists in the Ozark Plateau of Arkansas. Variant larvae with predominantly light head coloration occur in Ontario. Local populations are recorded from streams flowing southwards out of the moraine area parallel to Lake Ontario in Northumberland and Hastings counties where they may occur with Appalachian-type H. bronta. Light coloured//, slossonae also occur in some streams along the north and western shores of Lake Superior, while populations of the darker, more common form are found in other suitable streams. A population with unpatterned yellow head coloration is recorded from the Whitewater River in North Carolina. Materia] designated "typ." or with no designation is typically dark with one, two, or three light median spots; "var." material represents variant coloration, either a light background with dark patterns, or a dark background with light lateral patches resembling the checkerboard pattern. METAMORPHOTYPES EXAMINED ALBERTA: Battle River, at Highway 1 near Highway 792, 15 VI 79 (15). COLORADO: Grand County, Kenny Creek, near Hot Sulphur Springs, 1 1 VIII 73, SDS (2). MANITOBA: Duck Mountain Provincial Park, Garland River, 1 VII 62 (1 and many pupae); Riding Mountain National Park, Edwards Creek, 2 VII 62 (10). MINNESOTA: Hubbard County, Lasalle Creek at No Name Road, 2 VI 81, #81 1088 (6 and 10 prepupae). MONTANA: Deer Lodge County, Clark Fork River at Deer Lodge, 3 VIII 73, SDS (1). ONTARIO: Algoma District, Chippewa River at 71 Highway 17, 4 VI 71, #710325 (1); Obatanga Provincial Park, small stream at Highway 17, 8 VI 80, #801026 (1 and 50 larvae); Durham County, Duffin Creek at Greenwood Conservation Area, 3 VII 80, #801038 (1 and 30 larvae); Ganaraska River, 23 VII 73 (3 and many var. larvae); Wilmot Creek, 10 Vll 52 (4 var.); Grey County, stream at Highway 6 near Mount Forest, 6 VI 76 (1 and 30 larvae); Negro Creek at Highway 6, 6 VI 76 (3 var., 1 typ. and 10 var., 50 typ. larvae); North Spey River, Highway 10 south of Rockford, 17 V 76 (2 var., 16 typ. and 2 var., 20 typ. larvae); Saugeen River at Durham Conservation Area, 21 V 76 (5 var. and 20 var. larvae); Northumberland County, small stream off Highway 45 near Baltimore, 23 V 80, #801009 (5 and 20 larvae); Hope Township, Ganaraska River, small tributary, concession 5 west of Highway 28, 26 V 76 (1 and 10 larvae); Peel County, Humber River, at Palgrave, #396 (1; no date available); Albion Hills, 26 V 76 (1); 8 VI 76 (3); 2 VI 76 (1); Mono Mills, 26 V 76 (1); 22 V 77 (2); 4 VIII 76 (1); Credit River, Belfountain, 6 VII 61 (2); Forks of the Credit, 31 V 76 ( 1); 2 VI 76 (3 and 20 larvae); 17 VI 76 (2); Rainy River District, small stream at Route 1 1, 103.3 km east of Fort Francis, 11 VI 71, #710387(1 and 6 larvae); Thunder Bay District, Blend Creek near Sibley Provincial Park, 8 VI 71, #710356 (4 and 10 larvae); Coldwater Creek at sideroad off Ouimet Canyon Road, 10 VI 80, #801031 (3 and 15 pupae and 100 var., 200 typ. larvae); Sunshine Creek at Matawin River, 10 VI 80, #801030a (5 and 10 larvae); Cloud River at Cloud River Road, 23 VII 80, #801039 (1 and 3 var. larvae); Little Whitefish River at Highway 593, 24 V 81, #811066 (2 and 5 larvae). VERMONT: Addison County, small stream at foot of Moss Glenn Falls, Route 100 south of Warren, 26 VII 69, #690375 (1 and pupa). LARVAE EXAMINED ALBERTA: Bigoray River at Highway 753, 19 VI 79 (1); Little Red Deer River at Highway 922 north of Highway 582, 23 VI 79 (3); Medicine River at Highway 766, 14 VI 79 (2); Pembina River, at Highway 654, 21 VI 79 (1); crossing Highway 16, 10 VI 62 (2); Rose Creek at Highway 922 north of Highway 606. 14 VI 79 (8); confluence of Sheep and Highwood rivers, Highway 552, 12 VI 79(3); Willow Creek at Highway 527, 12 VI 79 (1); tributary of Willow Creek at Highway 520 west of Claresholm, 12 VI 79 (1). MANITOBA: Duck Mountain Provincial Park, Cowan Creek, 28 X 80, #801068 (30); Favel River, 50.5 km from Blue Lake Campground on Highway 366, 15 VIII 69, #690336(3); Garland River, 12 VI 62 (30); 12 VII 62 (10); North Pine River, 29 V 81, #81 1078a(15); Overflowing River Provincial Park, Overflowing River, 4 VIII 70, #700481 (1); Riding Mountain National Park, Edwards Creek, 1 1 VI 62 (75). MINNESOTA: Clearwater County, Mississippi River at Minnesota Road 37, 2 VI 81, #811087 (3). NEW BRUNSWICK: Charlotte County, Waweig River, outlet of pool at Highway 765. 14 VIII 80, #801048 (2). NEW JERSEY: Sussex County, Stokes State Forest, Big Flat Brook, 16 IV 77, JSW (1). NEW YORK: Delaware County, Beaverkill River at Route 17, Exit 92, 20 X 80, #801065 ( 1 and 1 reared); Tompkins County, Six Mile Creek at Slaterville Springs, 9 IX 66 (1). NORTH CAROLINA: Jackson County, Whitewater River above falls, 15 V 79, GAS (20 var.); Swain County, Great Smoky Mountains National Park, Bryson City, Deep Creek at Deep Creek Campground, 21 V 70, #700365 (20); Oconoluftee River at Smokemount, 1 IV 76, INHS (25); Transylvania County, Whitewater River, Route 171 north of Salem, 18 V 70, #700353 (20 var., 4 typ.). NORTH DAKOTA: Pembina County, Icelandic State Park, Renwick Lake, Tongue River at Rcnwick 72 Dam. 8 VIII 81, #813013 (1). OHIO: Champaign County, Riser Lake State Park, stream entering Kiser Lake. 27 IX 67 (2); Morrow County, small stream at Route 97 northwest of Lexington. 1 VIII 68 (15). ONTARIO: Algoma District, small stream at Highua> 17. 30.1 km south of Batchawana Bay Provincial Park. 4 VI 71, #710320 (50 and man\ pupae); Bruce Counts . 8 km north of Wiarton, Highway 6, VII 60 (1 var.); Cochrane District, Moosonee, Cemetery Creek, 8 VIII 80 (2); Natatishee Creek, 26 VIII 80(2): Pitopiko River at Route 11, 27.7 km west of Shekak River, 25 VI 71. #710472(1): Thunder Creek at Highway 101, 21.4 km west of Timmins, 19 V 72, #720163 (1); Durham County, Duffin Creek at Greenwood Conservation Area. 21 III 72(2): 22 V 80. #801007 ( 1); Leskard, 12 VI 53(1 var.); Grey County, stream at junction of Sideroad 25 and Concession 12, 23 II 80 (16 var., 40 typ.); Euphrasia/St Vincent Township Line. Bighead River, 27 VI 80 (2); Holland Township. Spring Creek. 4 VI 80 (5); Holland/Sydenham Township Line, tributary of Bighead River. 29 V 80. #801012 (6); #801015 ( 160); Walters Creek, 29 V 80, #801016 (10); Minniehill Creek. 8 VI 80 (20); Rocklyn Creek, 27 VI 80 (2); St Vincent Township, Minniehill Creek. 9ul0 VI 79 (2); 1 X 79 (40); Sydenham Township. Telford Creek. 8 VIII 79 (17); Kenora District, Kiruna Lake, 10 VII 81, #810023g (1); 12 VII 81. #8 10029c (1); Crystal River, 1 VI 78 ( 1 var.); Florence Creek at Route 105.30.1 km south of Ear Falls, 16 VI 71, #710413 (2); small stream at Route 105. 23.8 km south of Red Lake, 16 VI 71, #710411 (10); Lanark County, Fairs Creek at Lanark County Road 8. 30 VIII 72 (4 var.); Northumberland County, small stream at Van Luven Road north of Baltimore, 27 V 80, #801011 (20); Mayhew Creek tributary, 26 V 76 (80); Peel County, Credit River at Alton Concession IV, 27 VI 52 (2 var.); Credit River at Forks of the Credit, 24 XI 78 (70); 28 IX 52 (3); 20 VIII 52 (4); 9 VI 75 (30); Humber River, at Sideroad 25, Palgrave, 6 XI 78 ( 15); 1 XII 78 (30); 2 XI 78 (30); at Albion Hills Conservation Area, 15 VIII 75 (1): Renfrew County, small stream at Highway 17 between Arnpriorand Renfrew, 28 V 60 (2 var.); Khartum, 20.9 km southwest, small stream at Highway 41, 23 VI 73, #730109 (35 var.); Simcoe County, stream at Highway 11, 15.8 km north of Highway 400 cutoff. 21 VIII 67 (1); Grouse Creek, East Oro, 13 VII 52 (30 var., 45 typ.); Hawkestone, 12 VIII 52 ( 1); Sudbury District, Eastman Creek at Highway 101, 55 km west of Timmins, 23 V 72, #720181 (5); Espanola, Norton's Creek, 8 VI 81 (5); Thunder Bay District, Beardmore, 8.7 km northeast, stream at Highway 11, 25 VI 71. #710447(2 var.); Cloud River at Cloud River Road, east of Highway 61, 10 VI 80, #801029(100 var.); 24 V 81, #81 1065 (20 var., 10 typ.); Coldwater Creek tributary. 21 V 81. #81 1057a (50); Creelman Creek at Route 11, 21.9 km southwest of Geraldton, 23 VI 71, #710451 (35 var.); Current River at Highway 527, 10 VI 80, #801033 (1); Dublin Creek at Highway 17, 9 VI 80, #801028 (10); Firehill Creek at Highwa\ 17. 19 V 81, #811050 (10); Geraldton, 40.7 km north, stream at Route 584, 24 V 71, #710463 (15); Jackpine River at Highway 17, 19 V 81, #81 1049a (100); Joe's Creek near Sibley Provincial Park, 20 V 81, #811056(15 var., 5 typ.) Kakabeka Falls Provincial Park, Kaministikwia River, 19 VI 71, #710434 (2) Mc Vicar's Creek at Cumberland Street, Thunder Bay, 10 VI 80, #801046 (10) Pearl. Pearl River at Highway 17, 12 VI 80, #801036 (10 var.); 21 V 81, #811059 (6 var); Sibley Creek near Sibley Provincial Park, 20 V 81, #81 1055a (50 var., 50 typ); Sturgeon River at Route 11, 17.9 km northeast of Jellicoe, 22 VI 71, #710450 (1 var); small stream at Highway 17, 15 km east of Thunder Bay, 19 VI 71, #710432(40): Wolf River at Highway 17, 21 V 81, #81 1058 ( 12 var., 3 typ.); Wolf 73 River tributary on logging road east of Highway 527, #801032 (30 var., 10 typ.); Timiskaming District, stream at road to Esker Lakes Provincial Park, Kirkland Lake, 24 V 72, #720186 (35); Victoria County, Manvers Township, Fleetwood Creek, 1 VI 79 (2); Pigeon Creek, 11 VII 79 (2). PENNSYLVANIA: Linesville, Linesville Creek, Pymatuning Laboratory of Field Biology, 17 VII 64 (3); Potter County, stream at road 0.8 km west of Route 44, 16.1 km north of Coudersport, 15 V 68 (2). SASKATCHEWAN: Cypress Hills Provincial Park, Battle Creek, 28 VI 62 (10); Pierceland, stream on Highway 55, 15 VIII 70, #700546 (1). VIRGINIA: Bedford County, Montvale Wayside, 10 V 76 (1); Botetourt County, small stream at Route 43, 3.2 km south of Buchanan, 19 IV 68 (1); Craig Creek, 9 V 76 ( 1); Craig County, Barbour's Creek, 8 V 76 (1); Floyd County, Little River, 17 IV 74 (1); Montgomery County, Mill Creek at Route 785, 10,12 IV 79 (6); north fork of Roanoke River, 16 IV 74 (1); Page County, Pass River, 9 V 76 (6); Wythe County, Reed Creek at Route 11, 2.9 km west of Wytheville, 10 VII 68 (1); 27 VII 69, #690377 (3). WEST VIRGINIA: Pocahontas County, stream in Bird Run Recreational Area, 5 X 67 (20); 28 V 84, #840093 (1); Mercer County, Camp Creek in Camp Creek State Park off Route 19 ca. 24.1 km north of Princeton, 27 V 84, #840086 (1); Randolph County, Gandy Creek in Monongahela National Forest off Route 112, 14 km south of Whitmer, 30 V 84, #840105 (10). Hydropsyche sparna Ross Hydropsyche sparna Ross, 1938a, p. 150, fig. 81, holotype male, allotype female; type locality, Lovells, Michigan, along Au Sable River. Hydropsyche sparna — Denning, 1943, pp. 134-136, fig. 24, female; fig. 25, pupa. Hydropsyche sparna — Ross, 1944, p. 97, fig. 361, male; fig. 387f, female. Hydropsyche sparna — Mackay, 1978, pp. 499-509, figs. 4b, 5a, 8a, larva. Symphitopsyche sparna — Schuster and Etnier, 1978, pp. 52-54, fig. 26, larva. DIAGNOSIS Although head colour pattern is variable, Hydropsyche sparna is easily separated from most H. morosa group species on the basis of the short pronotal seta 22. The species is distinguished from others with this character by the lack of numerous ap setae on the frontoclypeus, which appears smooth and shiny, and the presence of dark, erect parietal tp setae. In some areas, notably northern Ontario and Wisconsin, H. sparna occurring with a slightly elongate pronotal seta 22 may be indistinguisha- ble from larvae of H. alhedra. Head coloration is variable, ranging from solid light yellow to medium brown (as in Fig. 84), or patterned as//, alhedra anteriad of the tentorial ridge with one, three, or four indistinct light areas (Fig. 83), or as H. macleodi with the surface of the frontoclypeus posteriad of the tentorial ridge darker than the remainder of the head. 74 DESCRIPTION Head rectangular, width 0.97-1.10 mm. length 1.13-1.18 mm (14 larvae). Frontoclypeus appearing smooth and shiny, with few to several tp or up setae near frontoclvpeal suture. (Note: the secondary peg setae of the head are intermediate between strictl) tapered or blunt types.) Parietals with tp setae dark, erect, of uniform length dorsally; op setae inclined laterally;/?/ setae inconspicuous. Pronotum with anterolateral seta 22 short, cylindrical, approximately one to one and one-half times length of adjacent secondary setae; dorsally and laterally with tp setae dark, erect; ap setae inclined, light tan; /;/ setae pale. Mesonotum with seta 5 moderately long, fine, clear; dorsally and laterally with tp setae erect, lighter and longer than on pronotum; /;/ setae pale. Metanotum with seta 5 moderately long, fine, clear; dorsally and laterally v.nhtp setae erect, lighter and longer than on mesonotum, few short, inclined tp setae, and hi setae light but conspicuous. Procoxa with single long, dark seta 1, may be several short, dark si setae adjacent. Mesotrochanter with setae 2, 3, and 5 dark, long (on some individuals seta 5 may be clear or a dark seta 1 may occur); mesofemur with setae 3 and 4 long, dark, usually one or two shorter, dark Is setae between. Metatrochanter with setae 2 and 3 long, dark; metafemur with seta 3 long, dark, seta 4 clear or not distinguishable. Abdomen with erects/; setae clavate, similar in morphology to appressed/j/ setae. Venter of anal prolegs with long hi setae basally, laterally, and on caudal lobes, and dark or tan si setae basally and laterally. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 8-11; lateral branch, 11-16. BIOLOGY Hydropsyche sparna occurs in various habitats including cold, turbulent first order streams, waterfall basins, as well as larger, warmer, and slower streams (for life history patterns, see Mackay, 1979). H. sparna is collected with H. ventura, H. bronta, or//, slossonae in colder streams, and with H. walkeri, H. morosa, or//. alhedra in warmer streams. RANGE Hydropsyche sparna is widely distributed in eastern North America, occurring from the Maritime Provinces on the Atlantic coast southwards through the Appalachian Mountains, with northern range limits at the tree line in northern Quebec, along the northern shores of the Great Lakes, and westwards into Manitoba. H. sparna is recorded from Minnesota, Wisconsin, Michigan, and Pennsylvania, along the southern shores of the Great Lakes and southwards into Illinois. METAMORPHOTY PES EXAMINED MICHIGAN: Emmet County, west branch of Maple River at Route 31, 13 VI 72 (1 and 50 larvae). NORTH CAROLINA: Avery County, Linville River at Linville Falls Campground, 22 V 70, #700369 (2 and 2 larvae); Jackson County, Shoal Creek on U.S. 441 south of Cherokee, 1 IV 76 (2 and 20 larvae). ONTARIO: Algoma District, Sand River at Highway 17, 7 VI 80, #801024(1 and 20 larvae); Old Woman River at Highway 17, 6 VI 80, #801022 (2 and 150 larvae); Durham County, Duffin Creek at Greenwood Conservation Area, 22 V 80, #801007 (1 and 7 larvae); Grey County, Beaver River at Clarksburg, 21 V 76 (1 and 20 larvae); Halton County, Credit River, Glen Williams, #372 (1); #462 (1; dates not available); Hastings County, Moira 75 River, at Highway 401, Fry's Landing Park, 14 VI 79, #790016 (1); at Latta, 25 VII 71 (1 and 1 larva); 13 VI 76(2 and 15 larvae); 2 VII 76 (3); 15 VIII 76(1); Kenora District, small stream at Route 17, 38.6 km west of Vermilion Bay, 15 VI 71, #710409 (2 and 10 larvae); Lanark County, Mississippi River at Route 29, Packenham, 26 VIII 71, #710502 (1); Northumberland County, Ganaraska River, 19 VI 73, #730105 (1); small tributary, Hope Township, concession 5 west of Highway 28, 26 V 76 (2 and 10 larvae); tributary of Mayhew Creek, Concession I south of Highway 401, ca. 2.4 km west of Wooler Road, 26 V 76 (3); Shelter Valley Creek at 401, 26 V 76 (3 and 150 larvae); 13 V 76 (3 and 30 larvae); Peel County, Credit River, Belfountain, 17 VI 76 (1); 19 V 76 ( 1); Churchville, 11 VIII 76 (1 and 6 larvae); 2 VIII 76 (1); Erindale Park, 31 V 79. #790005 (1); Sudbury District, River Aux Sables, Massey, Chutes Provincial Park, 2 VI 71, #710305 (1 and 30 larvae); Thunder Bay District, Dublin Creek at Highway 17, 8 VI 81, #811095 (1 and 20 larvae); 15 km east of Thunder Bay, small stream at Route 17, 17 V71, #710432(1 and 50 larvae). TENNESSEE: Blount County, Little River, 9.2 km northwest of Townsend, Tennessee 73, 15 IV 78, #780068 (3). VIRGINIA: Hanover County, North Anna River Falls, 21 III 78 (1). VERMONT: Franklin County, Missiquoi River beside Vermont 78 east of Highgate Center, 26 VII 69, #690375 (2 and 10 larvae); Windsor County, small stream at Route 100 just south of West Bridgewater, 26 VII 69, #690376 (2). LARVAE EXAMINED GEORGIA: Union County, Canada Creek on forestry road ca. 9.7 km south of Suches, 17 V 84, #840045 (1). ILLINOIS: Vermilion County, Jordan Creek 3.2 km southwest of Oakwood, 12 IV 83 (6). MAINE: Penobscot County, Winn, Penobscot River, 18 IX 79, UM (2). MICHIGAN: Isabella County, Chippewa River, 15 VII 79, DF (6). NEW YORK: Delaware County, Beaverkill River at Exit 92 off Route 17, 20 X 80, #801065 (2); 6 V 82, #822504 (1); Tompkins County, Slaterville Springs, Six Mile Creek, 9 IX 66 (2). NEWFOUNDLAND: Avalon Peninsula, Manuels Stream below Thomas Pond Dam, 24 VI 71 (1). NORTH CAROLINA: Avery County, Linville River at Linville Falls Campground, Blue Ridge Parkway, 21-22 V 70, #700367 (6); Macon County, small stream at Route 441 south of Franklin, 9 VIII 68 (20); Swain County, Bryson City, Great Smoky Mountains National Park, Deep Creek at Deep Creek Campground, 21 V 70, #700365 (4); Transylvania County, French Broad River at junction of 215N and 64E, 9 V 78, #780091 (20). ONTARIO: Algoma District, Baldhead River at Highway 17, 17 X 80, #801057 (1); 15 V 81, #81 1038(1); Cedar Creek 37 km east of Marathon on Route 17, 6 VI 71, #710343 (2); Chippewa River at Highway 17, 4 VI 71, #710325 (4); small stream near Cigar Lake at Highway 17 ca. 32.2 km southeast of White River, 2 VIII 76, #760209 (10); Crystal Creek near Sault Ste Marie, 14 V 81, #811031 (15); tributary of Michipicoten River at Mission Road, 16 V 81, #81 1042 (3); stream at Old Mill Bay at Highway 17, 15 V 81, #81 1036 (1); Old Woman River, 30.6 km south of Wawa, 23 VIII 76, #760207 (8); Sand River at Highway 17, 15.6 km north of Agawa Bay Campground, 23 VIII 76, #760204 (3); 7 VI 80, #801024 (15); waterfall near Searchmont, 14 V 81, #811035 (1); small stream at Highway 17, 31.4 km south of Wawa, 5 VI 71, #710334 (1); Stokely Creek, #801018 (4); Cochrane District, Thunder Creek at Highway 101, 21.4 km west of Timmins, 19 V 72, #720163(1); Durham County, Clarke Township, Ganaraska River, 2 VII 79; Duffin Creek at 76 Greenwood Conservation Area. 3 VII 80. #801038 (1); Orono, Wilmot Creek. 10 VII 52 (10); Gre) County, Holland Township. Spring Creek. 4 VI 80 (12); HoUand/Sydenham Township Line. Walters Creek, 29 V 80. #801016a (20); North Spe> Ri\er. Highway 10 south of Rockford. 21 V 76; Rocklyn Creek, 26 VI 80 ( 10); St Vincent Township. Minniehill Creek. 1 X 79 (22); 10 VI 80 (13); Sydenham ["ownship, Telford Creek. 8 VIII 79 (25); Bighead River. 29 V 80, #801015 (15); Euphrasia/St Vineent Township Line, near Walters Falls, 27 VI 80 (21); Holland Township, 12 IX 79 (1); tributary at HoUand/Sydenham Township Line, 28 V 80, #801012 (30); Haldimand County. Grand River, Elora, 27 VII 60 (2); Haliburton County. Boshkung River. Sherborne Portage, 1 IX 77 (10); Hastings County, Moira River at Highway 401, 5 VI 79, #790007 (30); Kenora Distriet, Graves Creek, 7 VI 78 (1); Leeds County, Leeder Creek front of Yonge off bridge intersecting logging trail, 16 VII 80; Nipissing District, Algonquin Provincial Park, stream at Highway 60. 7.1 km east of Opeongo Lake Road, 11 V 72, #7201 18 (1); Madawaska River at Highway 60. 29.31 V 72, #720203 (6); Amable du Fond River, Samuel de Champlain Provincial Park, 20 V 77, #770033 (10); Peel County, Credit River, Belfountain. 17 VI 52 (2); 29 IX 52 (4); 1 X 70 (7); Forks of the Credit, 3 VI 52 (20); 20 VIII 52 (30); 29 IX 52 (20); 13 X 78 (100); 21 XI 78 (20); Erindale, 30 V 73 (20); 15 IX 70 (1); 5 IX 52 (6); Humber River at Sideroad 25, Palgrave, 6 X 78 (10); 1 XII 78 (20); 3 IX 78; Rainy River District, Pickerel River at Highway 11, 11 VI 80, #801035 (60); Renfrew County, Arnprior, Waba Creek, 9 VII 54 (10); Simcoe County, East Oro, Grouse Creek, 13 VII 52 (5); Sudbury District, Alton, Credit River at Concession IV, 27 VI 52 (15); Eastman Creek at Highway 101, 55 km west of Timmins, 23 V 72, #720081 (2); Espanola, Norton Creek, 10 VI 81 (3); Thunder Bay District, Creelman Creek at Route 11, 21.9 km southwest of Geraldton, 23 VI 71, #710451; Current River at Highway 527, 10 VI 80, #801033 (20); Dublin Creek at Highway 17, 9 VI 80, #800128 (50); 19 VIII 80, #800160 (25); Kakabeka Falls Provincial Park, Kaministikwia River, 19 VI 71, #710434 (1); McLeans Creek at Highway 17. 24 VIII 76, #760211 (20); 18 V 81, #811044 (20); North Current Ri\er at Highway 527, 10 VI 80, #801033 (25); Pearl River at Highway 17, 12 VI 80. #801036 (4); 21 V 81, #811059 (10); Rheo River entering Lynn Lake near Schreiber, 20 I 68 (8); small river at Highway 17 ca. 1.5 km east of White River, #801027 (100); Timiskaming District, Kelly Creek at Highway 101, 46.3 km west of Timmins, 23 V 72, #720183 (17). TENNESSEE: Sevier County, stream at Route 73, 14.5 km east of Gatlinburg, 3 X 67 (6). VIRGINIA: Amherst County, tributary of James River beside Blue Ridge Parkway near junction with Route 501, 19 IV 68 (4); Lower Otter Creek at Lower Otter Creek Overlook on Blue Ridge Parkway, 16 IV 68 (6): Bath County, stream in Blowing Springs Recreational Area on Route 39, 5 X 67 (4); Cowpasture River, 9 V 76 ( 1 ); Page County, Pass River, 9 V 76 ( 1 ); Patrick County. Rock Castle Creek, 16 V 76 (1); Roanoke County, Roanoke River just west of Roanoke on Route 11, 28 VII 69 (15). WEST VIRGINIA: Pocahontas County, stream in Bird Run Recreational Area, Route 84, 5 X 67 (3). Hydropsyche tana Ross Hydropsyche tana Ross, 1938a, p. 151, fig. 83, holotype male, allotype female; type locality, near Harrison, Montana. 77 Associated here for the first time, the larva of Hydropsyche tana is described on the basis of a single larva collected with a series of metamorphotypes and adults from Clearwater, Montana. DIAGNOSIS With many clear, inconspicuous bl setae distributed on the frontoclypeus and an unpatterned brown head, Hydropsyche tana is similar to H. amblis but is distinguished from that species by the surface of the frontoclypeal sclerite, smooth posteriad of the tentorial ridge in H. tana, roughly punctate in H. amblis. As well, the posterodorsal area of the parietals is light, suffused with brown along the coronal suture in H. tana, but entirely dark brown in H. amblis. Head coloration is brown, unpatterned, with light areas around eyes and laterally on posterior portion of parietals. DESCRIPTION Head width 0.90 mm, length 0.97 mm (one larva); head rounded, lateral margins convex. Frontoclypeus with numerous clear, inconspicuous bl setae mingled with longer, clear, inconspicuous hi setae on the area posteriad of the tentorial ridge. Parietals with dark, erect tp setae, dark, appressed, sharply acuminate ap setae (especially laterally), and dark hi setae visible in light areas. Pronotum with anterolateral seta 22 dark, moderately long, tapered; dorsally and laterally with dark, erect tp setae, dark, appressed ap setae and dark and conspicuous hi setae. Mesonotum with seta 5 dark, moderately long, truncate; dorsally and laterally with erect, dark tp setae and appressed, dark ap and hi setae. Metanotum with seta 5 moderately long, tan, truncate; dorsally and laterally with dark, erect tp setae and hi setae dark and conspicuous. Procoxa with seta 1 long and dark, and at least one dark si seta approximately one-half its length adjacent, as well as several short, dark si setae on the same surface. Mesotrochanter with setae 2, 3, and 5 long and dark; on one leg seta 1 is short and dark, on the other seta 1 is short and clear. Mesofemur with setae 3 and 4 long and dark, with a few shorter, dark Is or si setae near position 3. Metatrochanter with seta 3 long, dark, seta 2 clear; metafemur with seta 3 long, dark, seta 4 clear. Abdomen with erect sh setae clavate, mingled with appressed hi setae. Venter of anal prolegs with dark hi setae basally and laterally, with a few dark si setae on lateral surface. Gill filaments on outer bifid trunk of abdominal segment 111: mesial branch, 6-7; lateral branch, 8. BIOLOGY Hydropsyche tana is associated for the first time from Blackfoot River in the Helena National Forest, a cool, fast stream with a cobble and pebble bottom, flowing through fir forest and meadow. RANGE Hydropsyche tana occurs in Montana, Idaho, California, and British Columbia. METAMORPHOTYPES EXAMINED MONTANA: Lewis and Clark County, Blackfoot River at Aspen Grove Campground, 11.3 km east of Lincoln, 15 VII 81, #813020. 78 LARVAE EXAMINED As above, one larva. Hydropsyche venada Ross Hydropsyche venada Ross, 1941, p. 91, pi. IX, fig. 72, holotype male; type locality. Huachuca Mountains, Arizona. Associated here for the first time, the larva of Hydropsyche venada is described on the basis of numerous larvae collected with metamorphotypes from the Atacosa and Chiracahua mountains in Arizona, kindly loaned by O. S. Flint of the USNMNH. DIAGNOSIS Hydropsyche venada is readily distinguished from other larvae with reddish brown unpatterned heads by the numerous sharply tapered, erect, clear or ianap setae on the parietals. and the smooth frontoclypeus which lacks apparent setation. DESCRIPTION Head width 1.53-1.77 mm, length 1.61-1.77 mm (five larvae); head rounded, lateral margins convex. Frontoclypeus lacking apparent setation. Parietals with numerous clear or tan, attenuate and sharply tapered ap setae, occasionally with a few thicker, dark ap setae among them; seta 17 black, sharply tapered, and only slightly longer than nearby erect setae; hi setae clear or tan, inconspicuous. Pronotum with anterolateral seta 22 black, moderately long, sharply tapered; dorsally and laterally with attenuate, clear, erect ap setae, with a few longer, black a/? setae and long, clear Is setae among them; hi setae tan, sharply tapered, appressed. Mesonotum with seta 5 moderately long, clear tan or dark, sharply tapered; dorsally and laterally with attenuate, clear tan, appresseda/? setae, mingled withered, dark ap setae; hi setae dark, conspicuous. Metanotum with seta 5 moderately long, clear tan, sharply tapered; dorsally and laterally with attenuate, clear tan, erect tp setae;/?/ setae dark and conspicuous. Procoxa with seta 1 long and dark, and several dark Is setae adjacent. Mesotrochanter with setae 2, 3, and 5 long and dark, seta 1 present and usually dark, although clear on a few specimens; mesofemur with setae 3 and 4 long and dark, a few dark Is setae between them. Metatrochanter with setae 2 and 3 long, dark; metafemur with seta 3 long, dark, seta 4 usually dark, occasionally clear. Abdomen with erects setae dark and flattened, appressed sh setae tan and clavate, and appressed, tan hi setae. Venter of anal prolegs with dark ,s7 setae basally and laterally, mingled with dark hi setae. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 19-21; lateral branch, 27-30. BIOLOGY Hydropsyche venada occurs in permanent mountain streams in the southwest United States (for habitat description see Gray, 1981). RANGE Hydropsyche venada occurs in Arizona, New Mexico, and Nevada. 79 METAMORPHOTYPES EXAMINED ARIZONA: Cochise County, Chiracahua Mountains, East Turkey Creek, 9 VI 68 (20 and 8 larvae); Yavapai County, Atascosa Mountains, Sycamore Canyon, 14 VI 68, USNMNH (1 and many larvae). LARVAE EXAMINED ARIZONA: West Strawberry, Irvine Power Station, 17 VI 68, USNMNH (3). Hydropsyche ventura Ross Hydropsyche ventura Ross, 1941, p. 92, fig. 73, holotype male, allotype female; type locality, Costello Lake, Algonquin Park, Ontario. Symphitopsyche ventura — Schuster and Etnier, 1978, pp. 55-56, fig. 27, larva. DIAGNOSIS With numerous appressed a/? setae scattered on the surface of the frontoclypeus and a short pronotal seta 22, Hydropsyche ventura is readily separated from most morosa group species. H. ventura is distinguished from the closely related H. macleodi on the basis of the numerous appressed ap setae on the frontoclypeus which occur primarily posteriad of the tentorial ridge in H. ventura, but on the entire surface of the frontoclypeal sclerite in H. macleodi. They also differ in the number of gill filaments on the outer bifid trunk of abdominal segment III — H. ventura having 5 to 7 mesially and 8 to 10 laterally while H. macleodi has 4 to 6 mesially and 5 to 6 laterally. In H. ventura abdominal jTi setae are flattened, while in H. macleodi abdominal s/i setae are similar in morphology to appressed hi setae. Head colour is usually dark brown with no light frontoclypeal pattern, but occasional individuals may be light reddish brown with dark pigment posteriad of the frontoclypeal tentorial ridge. DESCRIPTION Head rectangular, width 0.97-1.05 mm, length 1.13-1.21 mm (six larvae). Frontoclypeus with inclined ap setae on entire surface of sclerite, most numerous posteriad of tentorial ridge. Parietals dorsally with ap setae dark, erect and inclined; laterally with ap setae few, dark, and appressed; hi setae conspicuous. Pronotum with anterolateral seta 22 short, dark, and somewhat tapered, although distally truncate; dorsally and laterally with ap setae dark, erect; hi setae dark, conspicuous. Mesonotum with seta 5 inconspicuous; dorsally and laterally with tp setae dark, erect and inclined posteriorly; ap setae dark, inclined anteriorly;/?/ setae conspicuous. Metanotum with seta 5 short, clear, fine, inconspicuous; dorsally and laterally with tp setae dark, erect and inclined posteriorly; hi setae conspicuous. Procoxa with long, dark seta 1, dark Is and/or si setae adjacent. Mesotrochanter with setae 2, 3, and 5 long, dark; mesofemur with setae 3 and 4 long, dark, often with shorter, dark Is setae between. Metatrochanter with seta 3 long, dark, seta 2 clear or not distinguishable; metafemur with seta 3 long, dark, seta 4 long, clear. 80 Abdomen with erect sh setae tlattened, mingled with appressed hi setae. Venter of anal proleg with long/;/ setae basally, laterally, and on caudal lobes. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 5-7; lateral branch, 8-10. BIOLOGY Hydropsyche venture occurs in cold, rapid unpolluted streams, often with H. slossonae or//, spartui. RANGE The range of Hydropsyche ventura is limited to the Appalachian Mountains from Tennessee and Virginia northeast to Maine, and westwards through Quebec into Ontario as far as Nipigon. METAMORPHOTYPES EXAMINED ONTARIO: Grey County, Holland/Sydenham Township Line, tributary of Bighead River. 28 V 80, #801012 (2 and 6 larvae); Northumberland County, small stream at first concession east of Baltimore, 1.6 km north of Highway 401, 26 V 76 (1); tributary of Mayhew Creek, concession 1 south of Highway 401 ca. 2.4 km west of Wooler Road, 26 V 76 (6). TENNESSEE: Scott/Campbell County Line, Jake Branch at Tennessee 63, 2 VII 76, GAS (1 and 2 larvae); White County, Lost Creek Falls, Lost Creek north of County Road 4448, 14 IV 76, GAS (1 and 2 larvae); 13 IV 77 (14 and 4 larvae). LARVAE EXAMLNED ONTARIO: Algoma District, stream at Highway 17 at Old Mill Bay, 15 V 81, #811036 (5); Alona Bay Creek at Highway 17, 17 X 80, #801055 (1); Speckled Trout Creek at Highway 17, 22 VIII 76, #760203 (25); Grey County, Walters Creek at Holland/Sydenham Township Line, 29 V 80, #801016 (2 and 2 adults); Muskoka District, Baker Creek, 6 VII 81, RJM (8); Nipissing District, small stream at Highway 60, 4.8 km east of Opeongo Lake Road, 1 1 V 72, #7201 19; Thunder Bay District, Dublin Creek at Highway 17, 3 VIII 80, #801043 (1 larva); 19 V 81, #811048 (adult); 8 VI 81, #811095 (adult). PENNSYLVANIA: Tioga County, Ansonia south of Colton Point, Right Branch Run, 3 VI 78, JSW (15). TENNESSEE: Overton County, spring run at Route 85 south of Alfred, 30 IX 67 (12). VIRGINIA: Highland County, stream at Route 84 east of Mill Gap, 5 X 67 (10). WEST VIRGINIA: Pocahontas County, stream in Bird Run Recreational Area, 5 X 67 (2); Mill Run, at Road 44, 20 km from Glady, 29 V 84, #840100 (2); Randolph County, tributary of Gandy Creek, at Road 1 12, 14.3 km south of Whitmer, 30 V 84, #840104 (3). Hydropsyche vexa Ross Hydropsyche vexa Ross, 1938a, p. 148, fig. 78, holotype male; type locality, Bloomer, Wisconsin. Hydropsyche vexa — Denning, 1943, pp. 124-125, fig. 14, allotype female. Hydropsyche vexa — Ross, 1944, p. 97, fig. 359, male. 81 The larva of Hydropsxche vexa is associated in this study for the first time, based on material collected in the Mississippi River several kilometres from the headwaters in Hubbard County, Minnesota. DIAGNOSIS Although the head has a checkerboard pattern, the larva is easily distinguished from other morosa group checkerboard species by the stout, reddish si setae ventrally on the anal prolegs with prominent sockets larger and darker than the sockets of the si setae on the ventral sclerite of abdominal segment IX, and the presence of a dark seta 1 on the mesotrochanter. The head and pronotum have a distinctive freckled pigmentation created by light setae in dark alveoli surrounded by a light ring against a dark background. The primary head setae are especially long, seta 14 being at least one-half the length of the head, the anterolateral pronotal seta 22 being approximately one-half the length of the pronotum. There are long, dark Is setae on the head as well. Head coloration is typically checkerboard, only slightly variable in the specimens examined. DESCRIPTION Head rectangular, width 0.85-1.05 mm, length 1.05-1.27 mm (five larvae). Frontoclypeus with clear or reddish, inconspicuous, appressed ap setae near lateral frontoclypeal angle. Parietals with ap setae inconspicuous, clear, erect and inclined, longer anteriorly; tp setae clear, erect, only found anteriorly, of various lengths, some long and distally enlarged; hi setae inconspicuous. Primary head setae dark and especially long. Pronotum with anterolateral seta 22 especially long (approx. one-half length of pronotum), dark; also pronotal seta 5 present, dark or clear, moderately long; dorsally and laterally with ap setae clear; appressed tp setae clear, erect, some moderately long, few in number; hi setae light. Mesonotum with seta 5 long and dark; dorsally and laterally with ap setae clear, erect and inclined; tp setae clear, erect, some quite long; hi setae light. Metanotum with seta 5 moderately long, clear; dorsally and laterally with tp setae clear, of various lengths, erect, few;/?/ setae dark, conspicuous. Procoxa with single long, dark seta 1. Mesotrochanter with setae 1, 2, 3, and 5 long and dark; seta 1 slightly shorter than setae 2, 3, and 5; some dark Is setae may be adjacent to these positions. Mesofemur with setae 3 and 4 long, dark; one or more dark Is setae present along the ventral margin of the femur. Metatrochanter with setae 2 and 3 long, dark; metafemur with setae 3 and 4 long, dark. Abdomen with erect sh setae clavate, similar in morphology to appressed hi setae; seta 5 dark and conspicuous on abdominal segments. Venter of anal proleg with reddish .sV setae stout and curved, basally, laterally, and on caudal lobes, with sockets darker and more prominent than sockets of si setae on ventral sclerite of abdominal segment IX; clear reddish ,s7 setae on lateral and caudolateral surfaces, thinner than basal si setae and not curved; hi setae basally, laterally, and on caudal lobes. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 9-12; lateral branch, 13-17. BIOLOGY Larvae of Hydropsxche vexa were collected from a flat, sandy bottom stretch of the Mississippi River, ca. 9.7 km from the headwaters in Hubbard County, Minnesota. 82 At this point the river was ca. 10 m wide, 1 m deep, the eurrent swift but not turbulent, the banks open and grassy; larvae and pupae were attached to submerged snags and a single rock partially buried in sand. A single larva was collected from a similar habitat in the Pine River, Florence County, Wisconsin. RANGE Hydropsyche vexa is recorded from New England, as well as the Mississippi and Red River headwater basins extending westwards into Saskatchewan, Alberta, and Idaho. H. vexa is infrequently collected, but has a northern, nearly transcontinental range extending from the Maritime Provinces in the east to Alberta and Idaho in the west. Although recorded from Manitoba and the north-central states, H. vexa has not to date been recorded from Ontario. METAMORPHOTYPES EXAMINED MINNESOTA: Clearwater County, Mississippi River crossing Minnesota Road 37, 1.6 km west of County Road 2, north of Lake Itasca Village, 2 VI 81, #81 1087 (5 and 10 larvae). LARVAE EXAMINED WISCONSIN: Florence County, Pine River at D' Agastino cabin, end of second road south of junction of County roads N and D, 4 VI 81, #811090 (1). Hydropsyche walkeri Betten and Mosely Hydropsyche maculicornis Walker, 1852, p. 113; type locality, Hudson Bay, St Martin's Falls, Albany River, Ontario; preoccupied — Betten and Mosely, 1940. Hydropsyche walkeri Betten and Mosely, 1940, p. 23, fig. 9, male; nom. nov. for//, maculicornis Walker, 1852, p. 113. Hydropsyche walkeri — Ross, 1944, pp. 96-97, fig. 358, male; Fig. 387a, allotype female. Symphitops\che walkeri — Schuster and Etnier, 1978, pp. 35-37, fig. 18, larva. Hydropsyche walkeri — Smith and Lehmkuhl, 1980, pp. 621-633, figs. 3.4,12, larva. DIAGNOSIS Although Hydropsxche walkeri has an extremely variable checkerboard head colour pattern, it is easily distinguished from other checkerboard species by setal characters. The frontoclypeus appears bare of secondary setation posteriad of the tentorial ridge, and the ventral membranous area of the anal proleg lacks the conspicuous si setae present on other checkerboard species, although short, fine, clear, inconspicuous si setae may occur laterally. H. walkeri also lacks a dark seta 4 on the metafemur. Colour patterns of the head of H. walkeri are extremely variable within the checkerboard type, ranging from dark background with light frontoclypeal patches (as in Fig. 71) through variations (as in Figs. 72-74) to solid yellow with a small area 83 of dark pigment suffusing the posterior frontoclypeal suture and coronal suture (as in Fig. 75). This dark area seems to be constant in all specimens. DESCRIPTION Head width 1.13-1.26 mm, length 1.29-1.45 mm (25 larvae); head in many populations appearing nearly square with lateral margins parallel. Frontoclypeus lacking apparent setation posteriad of the tentorial ridge. Parietals with tp setae black, erect, distally enlarged, longer anteriorly; hi setae inconspicuous. Pronotum with anterolateral seta 22 long, dark; dorsaJly and laterally with tp setae dark, erect; hi setae conspicuous. Mesonotum with seta 5 moderately long, reddish; dorsally and laterally with tp setae dark, erect, distally enlarged; hi setae conspicuous. Metanotum with seta 5 moderately long, reddish; dorsally and laterally with tp setae dark, erect, distally enlarged; hi setae conspicuous. Procoxa with single long, dark seta 1, occasionally shorter, dark si setae adjacent. Mesotrochanter with setae 2, 3, and 5 long, dark; seta 1 clear, but longer than adjacent si setae; mesofemur with setae 3 and 4 long, dark. Metatrochanter with seta 3 long and dark, seta 2 variable, dark or clear; metafemur with seta 3 long and dark, seta 4 clear. Abdomen with erect sh setae clavate, mingled with appressed hi setae. Venter of anal proleg with short hi setae basally, laterally, and on caudal lobes; short, fine, clear si setae may occur laterally. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 10-16; lateral branch, 12-16. BIOLOGY Hydropsyche walked occurs in rivers of small to medium size with shallow riffle areas. The larvae are tolerant of some organic enrichment. H. walkeri is frequently collected with//, morosa and//, sparna. RANGE The range of Hydropsyche walkeri is primarily northeastern, extending into Wisconsin and Alberta to the west, north, and south of the Great Lakes, Quebec and Maine to the east, and Virginia to the south. H. walkeri is recorded to the tree line around Hudson Bay in Quebec and Churchill, Manitoba, but has not been reported from the Hudson Bay shore of Ontario. METAMORPHOTYPES EXAMINED ONTARIO: Algoma District, Baldhead River at Highway 17, 7 VI 80, #801025 (2 and 4 larvae); Sand River at Highway 17, 7 VI 80, #801024 (2 and 20 larvae); Grey County, Saugeen River at Durham Conservation Area, 21 V 76 (1); Hastings County, Moira River, at Highway 401, 13 VI 76(1); 15 VIII 76 (5); 5 VI 79, #790008(1 and 8 larvae); 14 VII 79 (7); at Latta, 25 V 73 (1); 13 VI 76 (1 and 15 larvae); 15 VIII 76 (6 and 5 larvae). VIRGINIA: Roanoke County, Roanoke River at Virginia 419 in Salem, 10 VII 76, GAS. WISCONSIN: Florence County, Pine River at Chipmunk Rapids Campground, 4 VI 81, #81 1089 (1 and 100 larvae). LARVAE EXAMINED ALBERTA: Whitecourt, Athabasca River, 20 V 82 (2). MAINE: Penobscot County, Winn, Penobscot River, 10 IX 79 (4). MINNESOTA: Clearwater County, Itasca 84 State Park, Mississippi River, 1 VI 81, #811086(2). ONTARIO: Algoma Distriet, Agawa River at Highway 17, 6 VIII 58 (1); Baldhead River at Highway 17, 15 V 81 , #811038(10); 17X80, #801057 (3): Chippewa River at Route 17, #710325 (7); 4 VI 80, #801017 (40); Sand River at Highway 17, 23 VIII 76, #760204 (30); Grey County. Beaver River at Clarksburg. 21 V 76 (1); 29 VII 76 (1); 17 VI 76 (10); Haliburton District, Hollow River below dam at Lake Kawagama, 29 V 67 (2); Hastings County. Moira River, at Highway 401, 15 VIII 76 (5); at Latta, 25 VII 71 (30); 6 I 75 (15); 13 VI 76 (30); Nipissing Distriet, Amable du Fond River, Samuel de Champlain Provincial Park, 20 V 77, #770033 (15); Rainy River District, French River at Highway 11. 25 VIII 76, #760213 (2); 11 VI 80, #801034(50); Pickerel River at Highway 1 1. 1 1 VI 80, #801035 (25); Sudbury District, River Aux Sables near Massey, 2 VI 71, #710305 (1); Thunder Bay District, Jackpine River at Highway 17. 19 V 81, #811049 (2); Pigeon River at Highway 593, 24 V 81, #811067 (2); North Current River at Highway 527, 10 VI 80, #801033 (30); Sturgeon River at Route 11, 22 VI 71, #710450 (15); Kakabeka Falls Provincial Park, Kaministikwia River, 19 VI 71, #710434 (10); Creelman Creek at Route 11, 21.9 km southwest of Geraldton, 23 VI 71, #710451 (5); Timiskaming District, Englehart River, Kap-Kig-iwan Provincial Park, 27 VI 71, #710484 (4). VERMONT: Franklin County, Missiquoi River at Route 78, east of Highgate Center, 26 VII 69, #690373 (1). VIRGINIA: Giles County, Little Walker Creek at Route 100 south of Pearlsburg, 10 VIII 68 ( 1). WEST VIRGINIA: Summers County, Greenbrier River at West Virginia 3, ca. 11.3 km east of Hinton, 28 V 84, #840087 (1). Hy dropsy che species (San Bernardino) Larvae of this species were taken from Barton Creek, a small tributary of the Santa Ana River, in the mountains of the San Bernardino National Forest, California. No other hydropsychids were found in the stream. The occurrence of numerous bl setae on the frontoclypeus suggests that the San Bernardino adult may be closely related to H. amblis and//, tana, and to the species represented by the Snake River and British Columbia larvae. DIAGNOSIS Similar in coloration to several western species with numerous bl setae covering the frontoclypeal sclerite, this species can be distinguished by the mesofemoral setae 3 and 4 which have no more than one dark si seta near either primary seta, as well as the bl setae on the frontoclypeus, which are clear and inconspicuous, the alveoli giving the sclerite a punctate appearance. Head coloration is variable, ranging from dark brown with a light area on the frontoclypeus anteriad of the tentorial ridge (as in Fig. 86) to medium tan or yellow with a dark area posteriad of the tentorial ridge. DESCRIPTION Head width 1.10-1.34 mm, length 1.26-1.53 mm (10 larvae); head rectangular, rounded, lateral margins convex. Frontoclypeus with clear, inconspicuous/?/ setae, the alveoli giving punctate appearance over entire surface of sclerite. Parietals with tp setae short, clear, erect, of even length dorsally, mingled with clear/?/ setae; laterally 85 with few ap setae, clear, inclined; hi setae dark and conspicuous; dorsal seta 17 clear, tapered but apically blunt. Pronotum with anterolateral seta 22 moderately long, clear reddish, with adjacent brown, curved ap setae; dorsally and laterally w'nhtp setae clear, erect; hi setae dark, conspicuous. Mesonotum with seta 5 moderately long, clear; dorsally and laterally with tp setae clear, erect; hi setae dark, conspicuous. Metanotum with seta 5 moderately long, clear; dorsally and laterally with tp setae few, clear, erect; hi setae dark, conspicuous. Procoxa with long, dark seta 1, and several short, dark si setae adjacent. Mesotrochanter with setae 2, 3, and 5 long, dark, occasionally with short, dark seta 1; mesofemur with setae 3 and 4 long, dark, may be shorter, dark Is seta near position 3. Metatrochanter with seta 3 long, dark; seta 2 usually dark, but may be light tan or clear in some individuals. Metafemur with seta 3 long, dark; seta 4 usually dark, but may be light in some individuals. Abdomen with erects/* setae clavate, longer than appressed/?/ setae. Venter of anal proleg with hi and/or fine si setae basally and laterally; occasionally one or two straight, reddish si setae on lateral surface. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 7-9; lateral branch, 10-12. BIOLOGY The larvae were taken from a small (ca. 0.5 m wide, 0. 1 m deep) stoney creek with a steep gradient. Running through a mature coniferous forest, the stream was warmer than others in the vicinity and is possibly a lake or marsh outflow. LARVAE EXAMINED Larvae collected in the San Bernardino National Forest, near San Bernardino, California, from Barton Creek, a small stream east of the South Fork of the Santa Ana River, crossing Route 38, elevation ca. 1981.2 m, 21 IV 81, #811002 (20). Hydropsyche species (Snake River) The larvae of this species were taken from Hell's Canyon Creek and Kinney Creek, both tributaries of the Snake River in Hell's Canyon, on the border of Idaho and Oregon. The occurrence of numerous hi setae on the frontoclypeus of these larvae suggests their close relationship with H. amblis and H. tana, as well as the species represented by the larvae from San Bernardino, California, and British Columbia. DIAGNOSIS With numerous hi setae on the frontoclypeal sclerite and head colour ranging from yellow to light brown, this species closely resembles the San Bernardino and British Columbia species. The cluster of dark Is and si setae on the mesofemur between setae 3 and 4 will distinguish it from them. Head colour within this population varies from yellow to light brown, the brown larvae having a median light patch anteriad of the tentorial ridge. DESCRIPriON Head width 1. 12-1.29 mm, length 1.20-1.45 mm ( 10 larvae); head rounded, lateral margins convex. Frontoclypeus with bl setae clear or dark; more obvious on posterior 86 surface in final instar, equally distributed on entire sclerite in earlier instars, and interspersed with occasional erect, tan //> setae on posterior surface. Parietals with clear or dark bl setae dorsally near coronal and posterior frontoclypeal sutures, mingled with tp setae, erect, clear or dark, and distally enlarged; laterally with few inclined ap setae longer anteriorly, tp setae longer and more dense anteriad of eyes, inclined and erect ap setae ventrolaterally; hi setae dark, conspicuous. Pronotum with anterolateral seta 22 clear tan, moderately long (three to five times length oi erect tp setae), somewhat tapered; anterior margin of pronotal sclerite with several inclined ap setae near seta 22; dorsally and laterally with tp setae tan, erect, mingled with occasional erect ap setae, and hi setae dark and conspicuous. Mesonotum with seta 5 inconspicuous; dorsally and laterally with clear, erect tp setae interspersed with dark, conspicuous hi setae. Metanotum with seta 5 inconspicuous; tp setae clear, erect, interspersed with dark, conspicuous hi setae. Procoxa with dark seta 1 occasionally flanked by a dark or clear Is or si seta. Mesotrochanter with setae 2, 3, and 5 long and dark, occasionally a shorter, clear seta 1 present; mesofemur with setae 3 and 4 long and dark, flanked by clear or dark Is setae. Metatrochanter with seta 2 long and dark, seta 3 clear or not distinguishable; metafemur with seta 3 long and dark, seta 4 clear or not distinguishable. Abdomen with erect sh setae clavate, mingled with appressed hi setae. Venter of anal proleg with hi setae basally and distally; there may also be fine, dark si setae. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 9-11; lateral branch, 9-14. BIOLOGY Hell's Canyon Creek and Kinney Creek are cold, swift, rocky streams, flowing through narrow gorges with lush deciduous riparian vegetation, although surrounding terrain is heavily grazed. LARVAE EXAMINED IDAHO: Kinney Creek at Hell's Canyon Road between Hell's Canyon Dam and Oxbow Dam, 3 V 81, #813122 (15). OREGON: Hell's Canyon Creek below Hell's Canyon Dam, 3 V 81, #813120 (20). Hydropsyche species (British Columbia) This description is based on two specimens from Haney, British Columbia, in the University of British Columbia Research Forest and a single specimen collected in Alaska, Revillagigedo Island, Lower Checats Lake. The occurrence of numerous bl setae on the frontoclypeus of these larvae suggests their close relationship with H. ambits and H. tana, as well as the species represented by the larvae from San Bernardino and Snake River. DIAGNOSIS With bl setae on the frontoclypeal sclerite, this species resembles other yellow to tan species with this feature, but can be distinguished by the tan or brown frontoclypeal bl setae and the mesofemur with setae 3 and 4 accompanied by no more than one dark si jeta. 87 Head coloration is light straw yellow with dark pigment on the frontoclypeus posteriad of the tentorial ridge. DESCRIPTION Head width 1.05 mm, length 1.21 mm; head rounded, lateral margins convex. Frontoclypeus with short, dark and clear bl setae (when clear the alveoli giving surface punctate appearance); bl setae longer and more conspicuous anteriad of the tentorial ridge. Parietals with bl and tp setae clear tan; short tp setae, erect dorsally and laterally; tp setae longer, clear tan, erect laterally; hi setae dense, dark, conspicuous. Pronotum with anterolateral seta 22 clear reddish, three times the length of adjacent setae, tapered, and distally blunt; dorsally and laterally with tp setae clear, inclined; hi setae dark, conspicuous, dense. Mesonotum with seta 5 short, clear, distally blunt; dorsally and laterally with tp setae clear, erect; hi setae dark, dense, conspicuous. Metanotum with seta 5 short, clear; tp setae clear, inclined posteriorly;/;/ setae dark, dense, conspicuous. Procoxa with long, dark seta 1, several short, dark si setae adjacent. Mesotrochanter with setae 2, 3, and 5 long and dark; mesofemur with setae 3 and 4 long and dark, occasionally dark Is setae near seta 3 or 4. Metatrochanter with seta 3 long, dark, seta 2 clear or not distinguishable; metafemur with seta 3 long, dark, seta 4 clear or not distinguishable. Abdomen with erect sh setae clavate, mingled with appressed hi setae. Venter of anal proleg with hi setae basaJly, laterally, and on caudal lobes. Gill filaments on outer bifid trunk of abdominal segment III: mesial branch, 10 and 11 in Alaska specimen, 9 in British Columbia specimens; lateral branch, 16 in Alaska specimen, 9 in British Columbia specimens. BIOLOGY Habitat data are not available for this species. LARVAE EXAMINED ALASKA: Revillagigedo Island, Lower Checats Lake, 22 VII 81 (1). BRITISH COLUMBIA: Haney, spring creek in University of British Columbia Research Forest, 23 X 79 (2). OREGON: Grant County, 14.5 km south of Dale, 1036.3 m elevation, 8 VI 55 (1). PHYLOGENETIC SIGNIFICANCE OF LARVAL CHAETOTAXAL CHARACTERS During the preparation of these diagnoses and key for larvae of the Hydropsyche morosa group, it became evident that sets of species sharing chaetotaxal characters coincided in many instances with subgroupings based on genitalic characters of adults. As well, larval head colour patterns, which are often not useful diagnostically, frequently correlate in a general way with setal and genitalic characters. Four species (//. sparna , etnieri ,ventura ,and macleodi) share larval characters of a short pronotal seta 22, anal prolegs lacking clear red spikelike (si) setae, metafemur 88 with seta 4 clear or absent, and noncheckerboard head patterns, and H. alhedra larvae occasional]) intergrade with//, sparna in the length of pronotal seta 22 and share the other characters common to the set. Males of these five species have on the phallus a quadrilobate dorsal membrane with both lobes armed with spurs or spicules, but lack apicolateral membranes on the phallotheca, a sclerotized ventral median process at the ape\ of the phallotheca, and a dorsal median lobe of the dorsal membrane; in these characters they are distinct from all other species in the morosa group. Another set of species with similar larvae (//. cockerelli, H. alternans, and H. aenigma), share a long pronotal seta 22, clear red spikelike (si) setae on the venter of the anal prolegs. metafemur with seta 4 dark, and mesotrochanter with a dark, conspicuous seta 1 . With the exception of the last character, H. centra also fits into this subgroup, and all four species have nearly square head capsules, a smooth frontoclypeus excavated anteriad of the tentorial pits, and a checkerboard head pattern. Adults of the four species are similar in having on the phallus a bi- or quadrilobate dorsal membrane with recurved apical spurs anterolateral^, a dorsomedian membranous lobe, and a sclerotized ventral median process dividing the tip into two eversible spicule-bearing apical membranes; spicule-bearing apicolateral membranes are absent. The phallus is similar in these species, and specific diagnoses are based mostly on characters of the tenth abdominal segment and apical segments of the inferior appendages; detailed diagnoses are given by Schefter, Wiggins, and Unzicker (1986). In another concordant set (H. morosa, bronta, cheilonis , piatrix , and walkeri), the larvae share characters of long pronotal seta 22, clear reddish spikelike (si) setae on the venter of the anal proleg, clear, inconspicuous seta 1 on the mesotrochanter, and checkerboard head patterns. With the exception of the penultimate character, H. vexa also falls into this set, and the adults of the six species are characterized by the presence on the phallus of apicolateral membranes, a bilobate dorsal membrane usually bearing apical spurs or spicules, and an attenuate apical segment of the inferior appendage (except//, walkeri). H. slossonae shares the genitalic characters of this set, but the larvae differ in the setation of the anal prolegs and the commonly observed head pattern, which is other than checkerboard. Three western montane species (//. amblis, H. tana, and H. venada) also have genitalic characters similar to the set just described, but are distinguished from them by strong development of the lateral process on the phallotheca and the sclerotization of the sclerous band proximal to the phallotremal sclerites. Larvae of//, amblis and H. tana are similar, having unpattemed heads, pronotal seta 22 of medium length, clear si setae absent ventrally on the anal prolegs, metafemoral seta 4 clear or absent, and minute, clear brushlike (bl) setae evenly scattered on the frontoclypeus. Two species for which larvae are not associated with the adult stage also share these characters (San Bernardino and Snake River), while the larva of//, venada has a smooth frontoclypeus and dark metafemoral seta 4. Because these subgroupings of species sharing genitalic characters are remarkably similar to subgroupings of species based on larval setal characters, we infer that chaetotaxy provides coherent character sets well integrated with other diagnostic characters. 89 ACKNOWLEDGEMENTS This study was supported by an operating grant (to G. B. Wiggins) from the Natural Sciences and Engineering Research Council of Canada. Collections in the Royal Ontario Museum contributing to this study were made over the past 30 years, assisted by financial support (to G. B. Wiggins) from the Canadian National Sportsmen's Show, the National Science Foundation of the United States, The National Research Council of Canada, and the Natural Sciences and Engineering Research Council of Canada. Assistance with field work was given by T. Yamamoto, R. Jaagumagi, B. D. Marshall, C. R. Parker, E. R. Fuller, and R. N. Vineyard. Additional materials were provided as loans or gifts from a number of institutions or individuals (listed under materials), sem micrographs were made with the assistance of Eric Lin using the scanning electron microscope installed in the Department of Zoology, University of Toronto, through a grant from the National Research Council of Canada. Susan Pasch and J.J. Thomason processed the manuscript; assistance was also given by E. R. Fuller. The study was presented by P. W. Schefter to the Department of Zoology, University of Toronto, in partial fulfillment of the degree of Master of Science, with financial support from a Natural Sciences and Engineering Research Council of Canada Scholarship, Ontario Graduate Scholarships, and a scholarship award from the Entomological Society of Canada. 90 LITERATURE CITED ALSTAD. D. N. 1980 Comparative biology of the common Utah Hy dropsy chidae (Trichoptera). American Midland Naturalist 103:167-174. BANKS. N 1905 Descriptions of new Nearctic neuropteroid insects. Transactions of the American Entomological Society 32:1-20. 1914 American Trichoptera — notes and descriptions. Canadian Entomologist 46:149-56.201-5.252-8,261-8. BETTEN. C 1934 The caddisflies or Trichoptera of New York state. New York State Museum Bulletin 292:1-576. BETTEN. C. and M. E. MOSELY 1940 The Francis Walker types of Trichoptera in the British Museum. London, British Museum (Natural History). 248 pp. BUCKLE, R L and W. J. MORSE 1966 The Caddisflies (Trichoptera) of Maine excepting the family Hydroptilidae. Maine Agricultural Experimental Station, Technical Bulletin 24:1-12. BOTOS.ANEANU. L. 1970 Trichopteres de la Republique Democratique-Populaire de la Coree. Annales Zoologici 27:275-359. CORBET. P S.. F. SCHMID. and C. L. AUGUSTIN 1966 The Trichoptera of St. Helen's Island, Montreal. 1. The species present and their relative abundance. Canadian Etomologist 98:1284-1298. DENNING. 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