TAXONOMIC REVISION AND PHYLOGENETIC ANALYSIS OF THE GENUS OREODYTES SEIDLITZ (COLEOPTERA: DYTISCIDAE: HYDROPORINAE) BASED ON LARVAL MORPHOLOGY

YVESALARIE Department of Biology, Laurentian University, Ramsey Lake Road, Sudbury, Ontario, Canada P3E 2C6

Abstract The Canadian Entomologist 129: 399-503 (1997) The larval morphology of the dytiscid genus Oreodytes Seidlitz was investigated through a detailed analysis of 16 Nearctic and two Palearctic species. Many structural features, especially those of chaetotaxy and porotaxy of head capsule, head appendages, legs, last abdominal segment, and urogomphi, were found to be useful for taxonomic and phylogenetic comparisons. Within the tribe Hydroporini, it is proposed that Oreodytes shares a monophyletic origin with the genera Deronectes Sharp, Scarodytes Gozis, Nebrioporus RCgimbart, and Stictotarsus Zimmermann. A tentative phylogenetic reconstruction of the genus Oreodytes, based on 29 larval characteristics, is provided. The classification of members of Oreodytes indicated by larvae is shown to be only partly reconcilable with the one indicated by adults. Once subdivided into three species-groups, Oreodytes now comprises four species-groups: the 0.picturatus, 0. obesus, 0.scitulus, and 0. quadrimaculatus species-groups. Oreodytes quadrimaculatus was found to share a monophyletic origin with the members of the 0.picturatus and 0. scitulus species-groups. The taxonomic status of the genus-name Neonectes J. Balfour-Browne is reconsidered as the larvae of N. natrix (Sharp) and N. babai Sat6 are revealed to be most similar morphologically to members of the 0.scitulus species-group.

Alarie, Y. 1997. RCvision taxinomique et analyse phylogknktique du genre Oreodytes Seidlitz (Coleoptera: Dytiscidae: Hydroporinae) i partir de caractkres larvaires. The Canadian Entomologist 129: 399-503.

Resume La morphologie larvaire du genre Oreodytes Seidlitz (Dytiscidae) est examinCe B partir de 1'Ctude dCtaillCe de 16 espbces NCarctique et de deux espbces PalCarctiques. Une grande variabilitC morphologique, particulibrement dans la chktotaxie et la porotaxie de la capsule cCphalique, des appendices ~Cphaliques,des pattes, du dernier segment abdominal et des urogomphes s'est rCvC1Ce trbs utile dans la comparaison taxinomique et phylogCnCtiquede ces espbces. I1 est suggCrC que, dans la tribu Hydroporini, Oreodytes partage une origine monophylktique avec les genres Deronectes Sharp, Scarodytes Gozis, Nebrioporus RCgimbart, and Stictotarsus Zimmermann. Une phylogCnie du genre Oreodytes est proposCe B partir de l'analyse de 29 caractkres larvaires. La classification ainsi gCnCrCe ne s'est rCvClCe que partiellement compatible avec celle proposCe antkrieurement B partir de caractkristiques morphologiques de I'adulte. SubdivisC qu'il Ctait en trois groupes B espbces, il est maintenant proposC que le genre Oreodytes en contienne quatre: les groupes B espbces 0. picturatus, 0. obesus, 0. scitulus et 0.quadrimaculatus. L'espbce 0.quadrimaculatus s'est rCvC1Ce Ctre plus Ctroitement like sur le plan phylogCnCtique a celles des groupes h espbces 0.picturatus et 0.scitulus avec lesquelles elle partage une origine monophylCtique. Le statut taxinomique du nom gCnCrique Neonectes J. Balfour-Browne est reconsidtrC Ctant donnC la grande ressemblance morphologique entre les larves de N. natrix (Sharp) et N. babai Sat6 et celle des espbces comprises dans le groupe B espbces 0.scitulus.

INTRODUCTION Members of the Holarctic genus Oreodytes Seidlitz are small dytiscid beetles (adult length 2.60-5.80 mm) adapted to cool or cold habitats and generally occur in rocky streams, creeks, rivers, and seepage habitats. Although widespread in the Northern Hemisphere, this genus is most diverse in the Pacific Northwest of North America where 18 of the about 29 400 THE CANADIAN ENTOMOLOGIST May/June 1997 known species (including the three species currently placed in Neonectes Zirnmermann) occur. In North America, most Oreodytes have a montane or primarily montane distribution. In the subfamily Hydroporinae, the genus Oreodytes belongs to the tribe Hydroporini Sharp. Although generally accepted by dytiscid workers, the monophyletic origin of this diverse tribe is not firmly established. Recently, Alarie and Nilsson (1997) have proposed a monophyletic origin for 11 genera of Hydroporini based on larval morphology. The taxonomic position of the genus Oreodytes within Hydroporini has been debated recently based on adult (Nilsson and Angus 1992) and larval (Alarie and Nilsson 1996,1997) morphology. It is suggested that Oreodytes share a close phylogenetic relationship with members of the Palearctic genera Deronectes Sharp and Neonectes J. Balfour-Browne and that all three genera occupy a more basal position within a clade comprising Oreodytes + Deronectes +Neonectes + Stictotarsus Zimmermann +Nebrioporus RCgimbart + Scarodytes Gozis. However, further analyses are required to refine this evolutionary hypothesis. In North America, 16 species of the genus Oreodytes were last revised by Zimmerman (1985) based on observations of structural features of adults [see Zimmerman (1985) for a detailed review of the taxonomic history of the genus name Oreodytes]. More recently, Larson (1990) and Alarie (1993) have revised the concepts of several species and added additional species to bring to 18 the total number of species. Of these, two [O. scitulus (LeConte) and 0.obesus (LeConte)] are ditypic (i.e. represented by two subspecies) and one [O. sanmarkii (C.R. Sahlberg)] is Holarctic in distribution. All but one species [O. laevis (Fall)] and one subspecies [O. scitulus scitulus (LeConte)] are restricted to western moun- tainous areas. Zimmerman (1985) subdivided the North American Oreodytes into three species-groups: the monotypic 0.quadrimaculatus, the 0. angustior (10 species), and the 0.scitulus (seven species) species-groups. Although a monophyletic origin of the genus was proposed by him, this hypothesis is hampered by inclusion of 0.quadrimaculatus (Horn) within Oreodytes. Based on adult features, it has been suggested that this species might be more closely related morphologically to the Palearctic genus Deronectes s.lat. (Fall 1923; Hatch 1953; Leech and Chandler 1956). Also, this species has sometimes been placed in Neonectes, another Palearctic genus for which the taxonomic status remains uncertain (Leech and Chandler 1956; Alarie and Nilsson 1997). Zimmerman (1985) proposed 0.quadrimaculatus as the sister-group of the remaining species of Oreodytes. The other two species-groups were believed to constitute natural entities, mainly on the basis of body shape. Species of the 0. angustior species-group are readily distinguished from those of the 0.scitulus group by their more globular shape and smaller size. Zimmerman (1985) recognized a monophyletic origin for each of these two lineages. Recently, I have undertaken a detailed study of the larval morphology of Nearctic members of Oreodytes. In holometabolous insects, immatures provide an array of new characters that supplement those of the adult stage and that may be used to refine phylogenetic hypotheses based on adult features. Because larvae of Holometabola share little in common with adults anatomically, they are likely to offer a rich, parallel source of information about phylogenetic relationships. However, the biology and morphology of immature stages of most Oreodytes species are unknown worldwide. The larvae of three species are known from the Palearctic fauna. These are 0. septentrionalis (Gyllenhal) (Nilsson 1982, 1987b), 0. alpinus (Paykull) (Nilsson 1982, 1987b), and the Holarctic 0.sanmarkii (De Marzo 1977, under 0.rivalis Gyllenhal; Nilsson 1982, 1987b). In the Nearctic, 0. scitulus is the only species for which the larvae was described (Matheson 1914, under Hydroporus septentrionalis Gyllenhal; Barman 1972). The objectives of my study were as follows: (1) to describe or redescribe the larvae of 16 species of Oreodytes found in the Nearctic region (Table I), with an emphasis on the chaetotaxy and the porotaxy of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi; (2) to provide keys and illustrations to facilitate their Volume 129 THE CANADIAN ENTOMOLOGIST 401 identification; (3) to study the phylogenetic relationships among members of Oreodytes; and (4) to compare the ground pattern of larval features of Oreodytes with those of other genera of the tribe Hydroporini.

MATERIAL AND METHODS Materials. Description of larval stages and taxonomic conclusions reported in this paper are based on examination of 307 specimens (107 first-instar, 64 second-instar, and 136 third-in- star larvae). Except for larvae of 0. alaskanus (Fall), 0. sanmarkii (Sahlberg), and in part 0.scitulus (LeConte) (population sample from QuCbec), which were obtained by association with adults, the larvae used in this study were reared ex ovo according to the technique described by Alarie et al. (1989). Sixteen of the 18 North American species are represented in this study (Table 1). The localities from which adults were collected are indicated following each species description. Despite a great deal of effort, I have been unable to rear the larvae of two species: 0. rhyacophilus Zimmerman and 0. humboldtensis Zimmerman. Eggs were obtained twice from 0. rhyacophilus without hatching. Oreodytes humboldtensis is a very rare species known only from the type locality. Despite thorough collecting efforts at the type locality on four separate occasions (over 3 years), I have been unable to get adult specimens of this species. When only few eggs were obtained, I gave priority to rearing first- and third-instar larvae. This is why the second-instar larvae of some species are missing. The larvae were killed in hot water (60°C) and preserved in 70% ethanol. Specimens representative of each of the three larval instars were disarticulated and mounted on standard glass slides with Hoyer's medium. Microscopic examination at magnifications of 80-800~was done using an Olympus BX50 compound microscope equipped with Nomarsky differential interference optics. Images were prepared through use of a drawing tube attached to the microscope. Voucher specimens are deposited in the larval collection of the author. Colour. Except for 0. sanmarkii, which was described from old preserved specimens, description of colour is based on freshly killed specimens. Morphometric Analysis. All measurements were made with the compound microscope equipped with a micrometer eyepiece, unless otherwise stated. The part to be measured was adjusted so that it was, as nearly as possible, parallel to the plane of the objectives. The characters and terms used in the morphometric analysis are mainly those used in my previous papers dealing with larval morphology of the Hydroporinae (Alarie 1989, 1991a, 1992, 1995; Alarie et al. 1990b; Alarie and Nilsson 1997) although some changes are noted. Accordingly, to ensure correct interpretations of some terms, notes of explanation are provided: Head length (HL): total head length including the frontoclypeus measured medially along the epicranial stem. Head width (HW): maximum width measured posterior to the stemmata. Length of frontoclypeus (FCL): from apex of the nasal to the back of the ecdysial suture. Width of frontoclypeus (FCW): width measured at level of base of articulation of primary seta FR13 (Fig. 2). This new measurement, which requires use of a compound microscope, shows a very low intraspecific variability. Occipital fpramen width (OcW): maximum width measured along the dorsal margin of the occipital foramen (Fig. 1). Length of antenna: derived by adding the length of each individual antennomere; comparison among antennomeres was made using the capital letter A with a number corresponding to the segment considered (e.g. A1 for antennomere 1); A3' is used as an abbreviation for the lateral elongation of antennomere 3. 402 THE CANADIAN ENMMOL001ST MayIJune 1997 Length of maxillary palpus: derived by adding the length of each individual palpomere. Length of labial palpus: derived by adding the length of each individual palpomere. Length of legs: derived by adding the length of each individual segment including the longest claw; the length of each segment was taken at the longest point except for the trochanter which includes only the proximal portion (the length of the distal portion being included in the femoral length); the length of the posterior metatarsal claw was compared with the length of the metatarsus. Maximum body width (MBW): maximum width measured at the level of the metathorax and abdomen segment 1; such measurement was done using a dissecting microscope. Dorsal length of last abdominal segment (LLAS): includes the whole sclerite meas- ured from the anterior margin of the prescutum to the apex of the siphon; siphon refers to the dorsal prolongation of the eighth abdominal segment (= last abdominal segment); the length of the siphon was determined by measuring the difference between the dorsal and ventral lengths of the segment. Length of urogomphus: derived by adding the length of each individual urogom- phomere; comparison between the two urogomphomeres was made using the abbreviation Uro (e.g. Urol for urogomphomere 1); Uro2' is used as an abbreviation for the length of urogomphomere 2 measured from its proximal margin to the point of insertion of primary seta UR8. The individual measurements defined below were used in calculating several ratios aimed at characterizing the body shape. Most of the ratios used in this paper are similar to those mentioned in my previous papers dealing with larval morphology of the Hydroporinae and, as such, are not defined herein. However, three new ratios are introduced. The frontoclypeus length (FCL)/the frontoclypeus width (FCW): used for charac- terizing the shape of the frontoclypeus. Species with a broad and short frontoclypeus will have lower values of FCLPCW whereas others, with a narrower and more elongate frontoclypeus, will have higher values of this ratio. The maximum body width (MBW)/the maximum width of the last abdominal segment (LASW): used for characterizing the relative body width. Species of Oreodytes have a fusiformate body shape which may be either narrow or broad. To characterize these two character states, a comparison was made between the maximum body width (MBW) and the maximum width of the last abdominal segment (LASW). The maximum width of the cephalic capsule (HW)/the maximum width of the occipital foramen (OcW): used for characterizing the presence of a distinct constriction posterior to the occipital suture. Some ratios referring to the relative length of abdomen segment 8 (LLAS) were found to have a high intraspecific variability within Oreodytes. These are length of siphon1LLAS and total length of urogomphus (or length of Urol)/LLAS. This seems to result from the relative elongation of the siphon which may vary within a species. As shown in this paper, the relative elongation of the urogomphus does reflect an evolutionary change within some members of Oreodytes which is best reflected if the length of the urogomphus is compared with the head width (HW). However variable they might be, values of the two previous ratios have been kept in this paper to facilitate a comparison with other hydroporine species described in the context of previous papers. Ratios used in the following descriptions were first calculated from the mean of the two values used in the ratio. When a ratio was found to have high interspecific variability (and, accordingly, a putative discriminating value), the entire range was calculated for this ratio. Chaetotaxic Analysis. Distinction between primary and secondary setae and pores was made for the cephalic capsule, head appendages, legs, last abdominal segment, and Volume 129 THE CANADIAN ENTOMOLOGIST' 403 urogomphi. They are coded according to the systems proposed by Alarie (1991b) for the cephalic capsule and head appendages, Nilsson (1988)and Alarie et al. (1990~)for the legs, and Alarie and Harper (1990)for the last abdominal segment and urogomphi. The characters and terms used in the chaetotaxic analysis are those found in Alarie (1989, 1991a, 1992,1995), Alarie et al. (1990b),and Alarie and Nilsson (1997).However, the ratio (UR4 - X)/(UR3 - UR4) has been excluded in this paper because of a high intraspecific variability in the relative position of primary setae UR3 and UR4.For each ratio used, the entire range was calculated.

CLASSIFICATION

KEY TO THE KNOWN GENERA OF NORTH AMERICAN HYDROPORINI 1. Frontoclypeus with two egg-bursters (Figs. 1, 21 -34) (first-instar) ...... 2 - Frontoclypeus smooth, lacking egg-bursters (Figs. 35-51) (second- and third-instar) ...... 8

2. Antennomere 3 lacking ventroapical spinulae; parietale with primary pore PAe present; maxillary stipes with primary seta MX5 present; basal articulation of primary seta UR8 more proximal on urogomphomere 2 (0.40 < Uro2'/Uro2 < 0.60)...... Hygrotus Stephens - Antennomere 3 with ventroapical spinulae present (Figs. 3, 12-20); parietale lacking primary pore PAe; maxillary stipes lacking primary seta MX5; basal articulation of primary seta UR8 inserted more distally on urogomphomere 2 (Uro2'/Uro2 > 0.70) (Figs. 73-76) ...... 3

3. Cephalic capsule with an occipital suture present and at least slightly constricted posteriorly at suture level (Figs. 1,21-34); maxillary cardo lacking (Figs. 6, 10); primary seta MX1 inserted on maxillary stipes (Figs. 6, 10); antennomere 3 generally lacking primary pore ANf (Figs. 3,4, 12-19) ...... 4 - Cephalic capsule lacking an occipital suture and not constricted posteriorly; maxillary cardo present; primary seta MX1 inserted on maxillary cardo; antennomere 3 with primary pore ANf always present ...... 5

4. Prementum lacking lateral spinulae; HL/HW < 1.lo...... Oreodytes Seidlitz - Prementum with lateral spinulae present; HL/HW > 1.20...... Nebrioporus Rkgimbart and Stictotarsus Zimmermann

5. Trochanter with primary seta TR2 absent; urogomphus long, more than 5.30 times LLAS (urogomphomere 1 more than 3.30 times LLAS) ...... 6 - Trochanter with primary seta TR2 present: urogomphus shorter, less than 5.10 times LLAS (urogomphomere 1 less than 3.00 time$ LLAS) ...... 7

6. Siphon very short, about 0.40 times LLAS; setae of legs short, longest setae of metafemur (setae FE8 and FE9) subequal in length to maximum width of metafemur; urogomphus with primary setae UR2 and UR3 contiguously articulated ...... Heterosternuta Strand - Siphon longer, about 0.60 times LLAS; setae of legs longer, longest setae of metafemur (setae FE8 and FE9) distinctly longer than maximum width of metafemur; urogomphus with primary setae UR2 and UR3 not contiguously articulated, seta UR3 almost equidistant in position relative to setae UR2 and UR4...... Neoporus Guignot

7. Stemmata absent; primary seta AB2 about 3.00 times longer than primary seta AB3; sclerites of body uniformly whitish, very slightly pigmented...... Hydroporus oblitus species-group - Stemmata present; primary seta AB2 less than 2.00 times length of primary seta AB3; sclerites of body greyish (live specimens) or brownish (alcohol-preserved specimens) ...... Hydroporus Clallville and Sanfilippodytes (Franciscolo) (= Hydroporus vilis species-group)

8. Antennomere 3 lacking ventroapical spinulae; parietale with primary pore Pae present; maxillary stipes with primary seta MX5 present...... Hygrotus Stephens 304 THE CANADIAN E3TOMOUXI.ST MayIJune 1997 - Antennomere 3 with a ventroapical spinula present (Figs. 3, 12-20); parietale lacking primary pore PAe; maxillary stipes lacking primary seta MX5 ...... 9

9. Maxillary cardo lacking (Figs. 6,lO); primary setaMX1 inserted onmaxillary stipes (Figs. 6- 10): antennomere 3 generally lacking primary pore ANf (Figs. 3,4, 12- 19)...... 10 - Maxillary cardo present; primary seta MXl inserted on maxillary stipes; antennomere 3 with primary pore ANf present ...... 11

10. Tibiae and tarsi with natatory setae absent (Figs. 54-61) ...... Oreodytes Seidlitz - Tibiae and tarsi with natatory setae present...... Nebrioporus RCgimbart and Stictotarsus Zimmermann

11. Urogomphomere 1 with secondary setae present (Figs. 77-81) ...... 12 - Urogomphomere 1 with secondary setae absent...... 13

12. Tibiae and tarsi with natatory setae absent (Figs. 54-61) ...... Heterosternuta Strand - Tibiae and tarsi with natatory setae present...... Neoporus Guignot

13. Antennomere 2 with one dorsomedian secondary seta; stemma, if present, subequal in width to maximum width of antennomere 1 ...... Hydroporus oblitus species-group - Antennomere 2 lacking secondary setae; stemma present, at least 2.00 times as long as maximum widthofantennomere 1 ...... Hydroporus Clairville and Sanjilippodytes (Franciscolo) (= Hydroporus vilis species-group)

DESCRIPTIONOF LARVAEOF OREODYTESSEIDLITZ (1887) (Figs. 1-81)

Diagnostic Combination. Body fusiformate; sclerites of body predominantly black (brownish in alcohol-preserved specimens); sternmata present; cephalic capsule slightly to distinctly constrictedposterior to occipital suture (Figs. 1,2,21-5 1 ); occipital suture present from first-instar larva (Figs. 1,21-34); parietale lacking pores PAd and PAe; antennomere 2 lacking secondary setae; antennomere 3 with a ventroapical spinula, with pore ANf present (Fig. 20) or absent (Figs. 3,4, 12-19 ); maxillary cardo absent (Figs. 6, 10); primary seta MX1 inserted on maxillary stipes (Figs. 6, 10 ); maxillary stipes lacking seta MX5; prementum lacking lateral spinulae (Figs. 8, 9); primary seta TR2 of trochanters present (Fig. 52); spinulae present (Figs. 54-59) or absent on ventral margin of tibiae and tarsi (Figs. 60, 61); legs lacking natatory setae (Figs. 54-61); posterotransverse carina present on thoracic terga of third-instar larva; spiracular openings present in third-instar larva; siphon strongly constricted posterior to insertion of urogomphi, and short, less than 0.20 times LLAS in third-instar larva (Figs. 62-72); primary setae UR2, UR3, and UR4 variously positioned on urogomphomere: either subequally distant (Figs. 73, 75,76) or more or less contiguous (Fig. 74); primary seta UR8 variously positioned on urogomphomere 2: distally, (Uro2'/Uro2 < 0.70) (Figs. 73-75) or apically (Uro2'/Uro2 = 1.00) (Fig. 76); urogom- phomere 1 with secondary setae in second- and third-instar larva (Figs. 77-81). Description, First-instar Larva (Figs. 1-34,52,53,62-68,73-76). Colour. Cephalic capsule, dorsal surface predominantly greyish black or predomi- nantly creamy white with a greyish black pattern posteriorly over parietale, basal portion of frontoclypeus, and occipital region; head appendages, predominantly greyish black to predominantly creamy white yellow with distal articles infuscate apically; thorax, terga greyish black or pale yellow; legs, creafny white to greyish black; abdomen, terga 1-6 predominantly creamy white to pale yellow or predominantly greyish black, terga 7 and 8 greyish black; urogomphus, predominantly creamy white to predominantly greyish black. Volume 129 THE CANADIAN ENTOMOLOGIST 405

Head (Figs. 1-34). HL= 0.42-0.69 mm; HW = 0.40-0.63 rnm; FCL= 0.31 -0.55 mm. Cephalic capsule (Figs. 1, 2, 21-34) about as long as broad (HL/HW = 0.98-1.17), pear-shaped, tapering posteriorly, with neck constriction slightly to distinctly delimited (HW/OcW = 1.39- 1.98); ecdysial suture well-developed, coronal suture short, 0.19-0.26 times HL; occipital suture present dorsally and laterally, absent ventrally; frontoclypeus bluntly rounded, longer than broad (FCLFCW = 1.53-2.66), short, 0.75-0.81 times HL, side at most slightly sinuate at level of lateral notches; lateral notches not visible dorsally; dorsal surface of frontoclypeus with an egg burster (ruptor ovi of Bertrand 1972); ventroapi- cal margin of frontoclypeus with 11- 16 spatulate setae (lamellae clypeales of Bertrand 1972) which are interrupted (Fig. 2), or not, medially for a short distance; lateroventral margin with numerous bulges; gular suture generally visible; ocularium present, stemmata not visible ventrally and subdivided into two vertical series, stemmata of the posterior row more widely spaced; tentorial pits visible medioventrally at about midlength, antenna (Figs. 3,4, 12-20 ) four-segmented, distinctly shorter than HW (length of antenna/HW = 0.56-0.85); antennomeres 2 and 3 longest, antennomere 2 variously elongate, distinctly shorter to subequal to antennomere 3 (A2/A3 = 0.64-0.91); antennomere 1 generally shortest, at most subequal to antennomere 4; lateral elongation of antennomere 3 (A3') distinctly shorter than antennomere 4 (A3'/A4 = 0.24-0.51); antennomere 3 with distinct ventroapical spinulae; primary seta AN2 variously positioned on antennomere 3: either medially, distinctly lower than ventral spinula or more apically, closer to or beyond ventral spinula (Figs. 12-20); mandible (Fig. 5) falciform, not toothed on inner margin, curved inward and upward apically, 0.47-0.54 times HL; maxilla (Figs. 6, 7, 10, ll), maxillary stipes short and thick, incompletely sclerotized ventrally; cardo, galea, and lacinia absent; maxillary palpus three-segmented, slightly to distinctly shorter than antenna (length of antennatlength of maxillary palpus = 1.11- 1.56); palpomere 2 longest, palpomere 3 shorter or subequal to palpomere 1; labium (Figs. 8,9), prementum trapezoidal to subrectangular, 1.5 1-2.24 times broader than long, lacking marginal spinulae; labial palpus two-segmented, subequal to distinctly shorter than maxillary palpus (length of maxillary palpusflength of labial palpus = 1.03- 1.33), palpomere 2 subfusiform, 1.09-2.17 times length of palpomere 1; all primary setae and pores of generalized hydroporine larva present, except pores PAd, PAe, and setae MX5; pore ANf is either lacking or present; seta MX1 articulated on maxillary stipes; setae MX2, MX3, and MX4 either short or very elongate; one additional seta sporadically observed on maxillary stipes. Thorax. Pronotum trapezoidal dorsally, ovate laterally, widest at posterior margin; length of pronotum about two times length of mesonotum; metanotum subequal to mesono- tum in length, both slightly wider than pronotum; pronotum without transverse carina; both meso- and metathoracic terga with an anterotransversecarina; tergal setation well-developed on lateral and posterior margin; ventral surface of thoracic segments membranous; spiracular openings absent. Legs (Figs. 52,53). Five-segmented; metathoracic legs longest, 1.20- 1.30 times length of prothoracic legs, 2.18-2.98 times HW; trochanter shortest, about 0.50 times length of coxa; coxa and femur longest, subequal in length, tibia slightly shorter than tarsus; tarsus with two claws, posterior claw slightly shorter than anterior claw on pro- and mesothoracic legs, subequal on metathoracic leg; posterior metathoracic claw about 0.63-0.88 times as long as metatarsus; spinulae on ventral margin of tibiae and tarsi present or absent; all primary setae and pores of generalized hydroporine larva present; length of longest between setae FE8 and FE9/width of metafemur = 0.79- 1.50; length of seta TI4/width of metatibia = 0.77-2.16; length of seta TA2/width of metatarsus = 0.52-1.63. Abdomen (Figs. 62-68). Eight-segmented; maximum width of body at level of metathorax and abdomen segment 1; MBWILASW = 2.89-4.60; LLAS = 0.12-0.21 mm; segments 1-7 dorsally sclerotized, segment 7 with a ventral plate well demarcated from 406 THE CANADIAN EXTOMOMGIST MayIJune 1997 reminder of sclerite, segment 8 completely sclerotized; all terga with an anterodorsal transverse carina and with long setae along lateral and posterior margins; spiracular openings absent; segment 8 short, LLAS/HW = 0.25-0.33, with siphon strongly constricted posterior to insertion of urogomphi; siphon short, bluntly rounded to acute apically, about 0.26-0.45 times LLAS; all primary setae and pores of generalized hydroporine larva present, except pore ABa; sensilla at apex of siphon sometimes extremely difficult to observe because of their size, presence of spinulae, and strong reduction of siphon; primary seta AB5 either short (Figs. 64-66) or elongate (Figs. 67, 68); additional setae sporadically observed on lateral margin of siphon (Figs. 64-68); length of seta ABll/LLAS = 0.50-0.82. Urogomphus (Figs. 73-76). Two-segmented; total length of urogomphus = 0.62- 1.43 mm (length of urogomphomere 1 = 0.28-0.97 mm); 1.36-2.55 times HW (length of Urol/HW = 0.64-1.68), and 4.37-8.70 times LLAS (length of Urol/LLAS = 2.18-5.28); urogomphomere 1 subequal to or longer than urogomphomere 2 (Urol/U~-02= 0.81 -2.39; Urol/U~-02'= 1.21-2.87), and about 2.25-4.73 times LLAS; all primary setae and pores of generalized larva present; one additional pore present (Figs. 73,76) or absent (Figs. 74,75) on urogomphomere 1; setae UR2 and UR3 inserted either ventrally (Fig. 74) or dorsolaterally (Figs. 73, 75, 76); primary setae UR2, UR3, and UR4 variously positioned on urogom- phomere 1: basal articulations contiguous or about subequally distant; verticillated setae UR5, UR6, and UR7 elongate, subequal in length; seta UR8 subterminal in position, distally articulated on urogomphomere 2 (Uro2'/Uro2 = 0.64- 1.00).

Description, Second-instar Larva. As first-instar larva except for the following characters: Head. HL = 0.55-0.97 mm; HW = 0.56-0.89 mm; FCL = 0.43-0.76 mm; HL/HW = 0.94- 1.12; cephalic capsule with a few secondary setae; FCLFCW = 1.75- 2.95; dorsal surface of frontoclypeus lacking egg-bursters; ventroapical spatulate setae more abundant than in first-instar larva and lacking a gap medially; lateral margin of parietale with 0- 14 temporal spines of various length and shape (seta-like, spine-like, or bluntly rounded); head appendages slightly shorter than in first-instar larva when compared with HW; antenna, length of antenna/HW = 0.54-0.74; antennomere 2 slightly shorter or subequal to antennomere 3 (A21A3 = 0.77- 1.06); antennomere 1 slightly longer than antennomere 4; lateral elongation of antennomere 3 (A3') short, A3'1A4 = 0.23-0.55; maxilla, palpomere 2 subequal to palpomere 1 in length (ratio = 0.80- 1.33); labium, palpomere 2 subequal to or longer than palpomere 1 (ratio = 0.90- 1.65); head appendages lacking secondary setae except for one or two lateroproximal setae on mandible. Thorax. Secondary setation present on each tergum. Legs. Metathoracic legs 1.20- 1.40 times length of prothoracic legs; secondary setae present, position and number of secondary setae as expressed in Tables 2 and 3; natatory setae lacking; where present, anteroventral marginal spinulae more faintly developed on metatibia and metatarsus; posterior metatarsal claw 0.52-0.77 times length of metatarsus. Abdomen. LLAS = 0.17-0.34 mm; segment 7 completely sclerotized; LLAS/HW = 0.27-0.39; secondary tergal setation present; siphon slightly shorter than in first-instar larva, 0.14-0.34 times LLAS; abdomen segments 7 and 8 with typical bluntly rounded secondary setae present or absent (Fig. 70). Urogomphus. Total length of urogomphus = 0.80-2.20 mm (length of urogomphomere 1 = 0.34- 1.52 mm); urogomphus 1.25-2.49 times HW (length of Urol/HW = 0.53- 1.75), and 4.30-7.27 times LLAS (length of Urol/LLAS = 1.91-4.75); urogomphomere 1 with numerous secondary setae; secondary setae either acute (Figs. 77, 78, 80, 81) or bluntly rounded apically (Fig. 79); Urol/Uro2 = 0.72-2.36 (Urol/Uro2'= 0.79-2.60); primary seta UR8 inserted more distally than in first-instar larva (Uro2'/Uro2 = 0.83- 1.00). Volume 129 TFlE CANADIAN MTOMOLOGIST 407 Description, Third-instar Larva (Figs. 35-51,54-61,69-72,77,78,80,81). As second- instar larva except for the following characters: Head. HL = 0.70- 1.35 mm; HW = 0.70- 1.30 mm; FCL = 0.52- 1.03 mm; cephalic capsule (Figs. 35-51), secondary setae more abundant than in second-instar larva; FCL/FCW = 1.79-3.19; lateral margin of parietale with 1-21 temporal spines; head appendages slightly shorter than in second-instar larva; antenna, antennomere 2 slightly shorter to slightly longer than antennomere 3 (A2/A3 = 0.86-1.19); antennomere 1 consis- tently longer than antennomere 4; lateral elongation of antennomere 3 short (A3'1A4 = 0.29-0.56); maxilla, palpus subequal or shorter than antenna (length of antennallength of maxillary palpus = 1.03- 1.29); palpomere 0.50- 1.02 times as long as palpomere 1; labium, length of maxillary palpus/length of labial palpus = 1.05- 1.45; palpomere 2, 0.70- 1.22 times as long as palpomere 1. Thorax. Secondary setation more abundant than in second-instar larva; posterotrans- verse carina present on thoracic terga, more weakly developed on protergum; mesopleural region with a spiracular opening on each side. Legs (Figs. 54-61). Secondary setation more abundant than on second-instar larva; position and number of secondary setae as expressed in Tables 4 and 5. Abdomen (Figs. 69-72). MBWILASW = 2.33-5.00; LLAS = 0.23-0.53 mm; seg- ments 1-7 each with a pair of spiracular openings; secondary setation more abundant than in second-instar larva; LLAS/HW = 0.32-0.47; siphon slightly shorter than in second-instar larva, 0.07-0.22 times LLAS. Urogomphus (Figs. 77, 78, 80, 81). Total length of urogomphus = 0.85-2.91 mm (length of urogomphomere 1 = 0.34-2.02 mm); 1.20-2.86 times as long as HW (length of urogomphomere 1/HW = 0.49- 1.93), and 3.5 1-6.37 times LLAS (length of UrolILLAS = 1.48-4.21); Urol/Uro2 = 0.62-2.59 (Urol/Uro2' = 0.68-2.76); primary seta UR8 inserted more distally than in second-instar larva (Uro2'/Uro2 = 0.89- 1.00).

KEY TO THE SPECIES-GROUPSOF OREODYTES SEIDLITZ

Key to Larval Instars

1. Frontoclypeus with two egg-bursters (Figs. 1,21-34)...... first instar - Frontoclypeus smooth, lacking egg-bursters (Figs. 35-51)...... 2

2. Mesothorax and abdominal segments 1-7 with spiracular openings absent ..... second instar - Mesothorax and abdominal segments 1-7 with spiracular openings present ...... third instar

Key to the Species-groups

1. Body broad, MBW/LASW > 4.20; ventral margin of protibia and protarsus lacking spinulae (Figs. 60, 61); urogomphus less than 1.60 times HW (urogomphomere 1 less than 0.80 times longer than HW); frontoclypeus in first-instar larva generally lacking a medial gap in the row of lamellae clypeales; temporal spines (second- and third-instar larvae only) weakly developed, of a similar shape if compared with other setae of the cephalic capsule (Figs. 45-5 1); primary seta AB5 extending well beyond apex of siphon (best seen in first-instar larva) (Figs. 67,68) ...... 0.obesus species-group - Body narrower, MBW/LASW < 3.80; ventral margin of protibia and protarsus with well-developed spinulae (Figs. 54-59); urogomphus more than 1.90 times HW (urogomphomere 1 more than 1.10 times longer than HW); frontoclypeus in first-instar larva with a distinct medial gap in the row of lamellae clypeales (Fig. 2); temporal spines (second- and third-instar larvae only) strongly developed, of a distinct shape if compared with other setae of the cephalic capsule (Figs. 35- 44); primary seta AB5 shorter, not extending beyond apex of siphon (best seen in first-instar larva) (Figs. 64-66)...... 2 408 THE CANADIAN ENTOMOLOGIST MayIJune 1997 2. Antennomere 3 with pore ANf present (Fig. 20); urogomphomere 1 lacking additional pore, at most 1.40times longer than urogomphomere2 (Fig. 75); Uro2'/Uro2 < 0.70 (in first-instar larva); protarsus with at least four secondary setae (second- and third-instar larvae) (Figs. 54-55) ...... 0.quadrimaculatus species-group - Antennomere 3 with pore ANf absent (Figs. 12-19); urogomphomere 1 with an additional pore present, generally more than 1.70 longer than urogomphomere 2 (Figs. 73, 76); Uro2'1Uro2 > 0.75 (in first-instar larva); protarsus (in second- and third-instar larvae) generally lacking secondary setae, if present, with at most two secondary setae (Figs. 56-59) ...... 3

3. Temporal spines bluntly rounded apically (second- and third-instar larvae only) (Fig. 35); abdomen segments 7 and 8 with one to three pairs of bluntly rounded secondary setae (Fig. 70) (second- and third-instar larvae only); primary seta UR8 inserted terminally on urogomphomere 2 (best seen in first-instar larva) (Fig. 76); small species...... 0.picturatus species-group - Temporal spines acute apically (in second- and third-instar larva only) (Figs. 36-43); abdomen segments 7 and 8 laclung bluntly rounded secondary setae (second- and third-instar larvae only) (Fig. 73); primary setae UR8 inserted subapically on urogomphomere 2 (Fig. 73); larger species ...... 0.scitulus species-group

THEOREODYTES QUADRZMACULATUS SPECIES-GROUP The 0.quadrimaculatus species-group includes only one species: 0. quadrimaculatus.

Oreodytes quadrimaculatus (Horn) (Figs. 20,34,44,54,55,65,70,75,77) Diagnostic Combination. Body narrower, MBW/LASW < 3.80; lamellae clypeales inter- rupted medially for a short distance (first-instar larva); antennomere 3 with pore ANf present and primary seta AN2 inserted medially (Fig. 20); temporal spines not bluntly rounded (Fig. 44); spinulae present on ventral margin of tibiae and tarsi (Figs. 54-55); abdomen segments 7 and 8 lacking bluntly rounded secondary setae (Fig. 70); primary seta AB5 not extending beyond apex of siphon (Fig 70); urogomphus elongate, more than 1.90 times HW (urogomphomere 1 more than 1.10 times longer than HW); urogomphomere 1 at most 1.40 times longer than urogomphomere 2, lacking an additional pore (Figs. 75, 77), lacking bluntly rounded secondary setae (Fig. 77); primary setae UR2, UR3, and UR4 nearly subequally distant, setae UR2 and UR3 inserted dorsolaterally and ventrally respectively (Fig. 75); primary seta UR8 inserted subapically on urogomphomere 2 (Uro2'/Uro2 < 0.70 in first-instar larva) (Fig. 75). Description, First-instar Larva (Figs. 20,34,65,75). Colour. Cephalic capsule (Fig. 34) predominantly creamy white to pale yellow, except parietale, black posteriorly; head appendages creamy white to pale yellow; thorax, proter- gum black, meso- and metaterga creamy white; legs creamy white to pale yellow, very lightly infuscate over distal segments; abdomen, tergum 1 creamy white to pale yellow, narrowly infuscate along anterior margin, terga 2-6 and 8 greyish black, tergum 7 yellowish grey; urogomphus greyish black. Head (Figs. 20,34). HL = 0.63-0.68 mm (Y = 0.66 mm, n = 3); HW = 0.57-0.63 mm (Y = 0.60 mm, n = 3); FCL= 0.50-0.55 mm (F = 0.52 mm, n = 3); cephalic capsule (Fig. 34) slightly longer than broad (HL/HW = 1.08- 1.12), with neck constriction distinctly delimited (HW/OcW = 1.8 1- 1.86); FCL/FCW = 1.94-2.10); frontoclypeus with side slightly sinuate at level of lateral notches; lamellae clypeales interrupted medially for a short distance; antenna (Fig. 20), length of antenna/HW = 0.81-0.85; A2/A3 = 0.66-0.67; A3'1A4 = 0.42-0.48; pore ANf present and seta AN2 inserted medially on antennomere 3; maxilla length of antennahengthof maxillary palpus = 1.32- 1.34; setae MX2, MX3, and MX4 short; maxillary stipes lacking additional seta; labium, length of maxillary palpus/length of labial palpus = 1.05- 1.07; palpomere 2, 1.38- 1.52 times length of palpomere 1. Volume 129 MECANADIAN ENI'OMOLOFTST 409 Legs. Metathoracic legs about 1.30 times length of prothoracic legs, and 2.54 times HW, posterior metathoracic claw about 0.85-0.88 times as long as metatarsus; spinulae present on ventral margin of tibiae and tarsi; length of longest between setae FE8 and FE9lwidth of metafemur = 1.22- 1.31; length of seta TI4lwidth of metatibia = 1.72- 1.97; length of seta TA2lwidth of metatarsus = 1.43- 1.59. Abdomen (Fig. 65). MBW/LASW= 3.34; LLAS =0.15-0.18 rnm (T =0.16 mm, n = 3); LLAS/HW = 0.26-0.28; siphon acute apically, about 0.35-0.41 times LLAS; primary seta AB5 not extending beyond apex of siphon; length of seta ABllfiAS = 0.80-0.82. Urogomphus (Fig. 75). Total length of urogomphus = 1.29-1.36 mm (Y = 1.34, n = 3) [length of urogomphomere 1 = 0.69-0.75 mm (Y = 0.73, n = 3)]; 2.15-2.33 times HW (length of Urol/HW = 1.16-1.28), and 7.70-8.70 times LLAS (length of UrolLLAS = 4.12-4.67); Urol/Uro2 = 1.17- 1.22 (Urol/Uro2' = 1.78- 1.82); urogomphomere 1 lacking additional pore; primary setae UR2 and UR3 inserted dorsolaterally and ventrally respec- tively; basal articulations of primary setae UR2, UR3, and UR4 nearly subequally distant; basal articulation of seta UR8 inserted subapically on urogomphomere 2 (Uro2'/Uro2 = 0.64-0.67). Description, Second-instar Larva. As first-instar larva except for the following characters: Colour. Cephalic capsule predominantly creamy white to pale yellow, except for some faint greyish maculae basally over parietale and occipital region; thorax, mesotergum predominantly creamy white except for a black strip along anterior margin; legs creamy white to pale grey. Head. HL = 0.90 mm (n = 1); HW = 0.82 mm (n = 1); FCL = 0.72 mm (n = 1); HL/HW = 1.05; cephalic capsule, FCL/FCW = 2.19; lateral margin of parietale with 12-14 strong temporal spines, acute apically; head appendages, length of antenna/HW = 0.74; A2/A3 = 0.77; labial palpomere 2, 1.12 times length of labial palpomere 1. Legs. Metathoracic legs 1.30 times length of prothoracic legs; position and number of secondary setae as expressed in Table 2; posterior metatarsal claw 0.63 times length of metatarsus. Abdomen. LLAS = 0.25 mm (n = 1); siphon, 0.20 times LLAS; abdomen segments 7 and 8 lacking bluntly rounded secondary setae. Urogomphus. Total length of urogomphus = 1.78 mm (n = 1) [length of urogom- phomere 1 = 1.04 mm (n = I)]; urogomphus 2.18 times HW (length of UrolIHW = 1.27), and 7.27 times LLAS (length of UrolILLAS = 4.25); urogomphomere 1 lacking bluntly rounded secondary setae; Urol/Uro2 = 1.40 (Urol/Uro2' = 1.67); primary seta UR8 inserted more distally than in first-instar larva (Uro2'/Uro2 = 0.84). Description, Third-instar Larva (Figs. 44, 54,55, 70,77). As second-instar larva except for the following characters: Colour. Cephalic capsule predominantly creamy white except for a narrow blackish pattern over occipital region (Fig. 44); thorax, metatergum with some piceous maculae medially and laterally; abdomen, tergum 8 creamy white to pale yellow anteriorly; urogomphus, urogomphomere 1 creamy white to pale yellow anteriorly. Head. HL= 1.14-1.22 mm (Y= 1.18, n = 5); HW = 1.03-1.10 mm (Y= 1.07, n = 5); FCL = 0.89-0.97 mm (Y = 0.94 mm, n = 5); cephalic capsule (Fig. 44), FCLIFCW = 2.12-2.27; lateral margin of parietale with 16-21 temporal spines; antenna, A21A3 = 0.87-0.91; A3'/A4 = 0.47-0.52; maxilla, length of antennallength of maxillary palpus = 1.15- 1.23; palpomere 2,0.78-0.85 times length of palpomere 1; labium, length of maxil- lary palpusllength of labial palpus = 1.07- 1.15; palpomere 2, 0.94- 1.04 times as long as palpomere 1. Legs (Figs. 54, 55). Position and number of secondary setae as expressed in Table 4; posterior metatarsal claw 0.52-0.55 times length of metatarsus. 410 THE CANADIAN ENTOMOLOGIST MayIJune 1997 Abdomen (Fig. 70). MBW/LASW= 3.00; LLAS = 0.36-0.41mm (Z = 0.38 mm, n = 5); LLAS/HW= 0.34-0.38; siphon slightly shorter than in second-instar larva, 0.15-0.18 times LLAS. Urogomphus (Fig. 77). Total length of urogomphus = 2.32-2.59 mm (T = 2.33 mm, n = 5) [lengthof urogomphomere 1 = 1.24-1.33 mm (T = 1.28 mm, n = 5)]; 2.13-2.27 times as long as HW (length of urogomphomere 1/HW = 1.15- 1.23), and 6.01-6.37 times LLAS (length of Urol/LLAS = 3.17-3.49); Urol/Uro2 = 1.10- 1.29 (Urol/Uro2' = 1.25- 1.44). Source of Reared or Associated Material. Eggs were obtained from adults collected at the following localities: CANADA. British Columbia. Duteau Ck, 5 km W Lumby, Hwy 6, 31.V.1992; USA. Washington. Pierce Co., Hall Ck at Hwy 12, 2 km W Packwood, 30.V.1995. Taxonomic Notes. Oreodytes quadrimaculatus is a medium-sized species which may be distinguished easily from other species of Oreodytes by the presence of primary pore ANf on antennomere 3, and the more proximal insertion of primary seta UR8 on urogom- phomere 2. The second- and third-instar larvae are also characterized by a greater number of secondary setae on the legs (Tables 4 and 5). Distribution. Oreodytes quadrimaculatus is distributed from western Alberta and southern British Columbia to Nevada and California.

THEOREODYTES PZCTURATUS SPECIES-GROUP (Figs. l,2, 16,35,58,59,66,72,76,78,79) Oreodytes picturatus and 0. angustior are the only two species assigned to the 0.picturatus species-group. Both species are fairly similar morphologically. Because only one specimen (a second-instar) of 0.angustior was available for study, the description of colour is based mainly on 0.picturatus. Diagnostic Combination. Body narrower, MBW/LASW < 3.80; lamellae clypeales inter- rupted medially for a short distance (Fig. 2); antennomere 3 with pore ANf absent, and primary seta AN2 inserted subapically, lower than ventral spinula (Fig. 16); temporal spines bluntly rounded apically (Fig. 35); spinulae present on ventral margin of tibiae and tarsi (Figs. 58, 59); abdomen segments 7 and 8 with some bluntly rounded secondary setae (Fig. 72); primary seta AB5 short, not extending beyond apex of siphon (Fig. 66); urogom- phus elongate, more than 1.90 times HW (urogomphomere 1 more than 1.10 times longer than HW); urogomphomere 1 at least 1.70 times longer than urogomphomere 2 (cannot be measured on second- and third-instar larvae), with an additional pore present (Figs. 76,78, 79), with bluntly rounded secondary setae present (Fig. 79) or absent (Fig. 78); primary setae UR2, UR3, and UR4 about subequally distant, setae UR2 and UR3 inserted dorsolaterally and ventrally respectively (Fig. 76); primary seta UR8 inserted apically on urogom- phomere 2 (Uro2'/Uro2 = 1.00, in first-instar larva) (Fig. 76). Description, First-instar Larva (Figs. 1,2, 16,66,76). Colour. Cephalic capsule predominantly greyish black except apically over fronto- clypeus, laterally over parietale and ocularium, and around egg-bursters creamy white; head appendages creamy white, except antennomere 4, apex of antennomere 3, maxillary palpomere 3, apex of maxillary palpomere 2, and apex of labial palpomere 2 infuscate; thorax, pro- and mesothoracic terga creamy white to pale yellow, metathoracic tergum greyish black; legs greyish, except coxae and trochanter creamy white; abdomen, terga 1, 7, and 8 greyish black, terga 2-6 creamy white to pale yellow; urogomphi greyish black, slightly paler proximally. Head (Figs. 1, 2, 16). HL = 0.44-0.48 mm; HW = 0.43-0.46 mm; FCL = 0.34- 0.36 mm; cephalic capsule (Figs. 1, 2) slightly longer than broad (HL/HW = 0.99-1.08), Volume 129 THE CANADIAN ENTOMOLOGIST 411 with neck constriction distinctly delimited (HW/OcW = 1.65-1.86); FCLJFCW = 1.83- 2.07); frontoclypeus with side not sinuate at level of lateral notches; lamellae clypeales interrupted medially for a short distance (Fig. 2); antenna (Fig. 16), length of antenna/HW = 0.70-0.73; A2/A3 = 0.74-0.81; A3'/A4 = 0.25-0.27); pore ANf lacking and seta AN2 inserted subapically, lower than spinula, on antennomere 3; maxilla, length of an- tennallength of maxillary palpus = 1.29- 1.32; setae MX2, MX3, and MX4 short; maxillary stipes lacking additional seta; labium, length of maxillary palpustlength of labial palpus = 1.11 - 1.16; palpomere 2, 1.37- 1.65 times length of palpomere 1. Legs. Metathoracic legs about 1.30 times length of prothoracic legs, and 2.63 times HW; posterior metathoracic claw about 0.75-0.78 times as long as metatarsus; spinulae present on ventral margin of tibiae and tarsi; length of longest between setae FE8 and FE9/width of metafemur = 1.09- 1.22; length of seta TI4/width of metatibia = 1.84-2.00; length of seta TA2/width of metatarsus = 1.14- 1.29. Abdomen (Fig. 66). MBW/LASW = 3.57; LLAS = 0.14-0.17 mm; LLAS/HW = 0.31-0.36; siphon acute apically, about 0.26-0.43 times LLAS; primary seta AB5 short, not extending beyond apex of siphon; length of seta AB 1ILLAS = 0.63-0.70. Urogomphus (Fig. 76). Total length of urogomphus = 0.82-0.89 mm (length of urogomphomere 1 = 0.55-0.58 mm), 1.88- 1.98 times HW (length of Urol/HW = 1.26- 1.33), and 5.85-6.32 times LLAS (length of Urol/LLAS = 3.92-4.17); UrolKJro2 = 1.94-2.13 [Uro1/Uro2'= 1.94-2.13 (range of values identical with the previous one because of the terminal position of seta UR8)]; urogomphomere 1 with one additional pore; primary setae UR2 and UR3 inserted dorsolaterally and ventrally respectively; basal articulations of primary setae UR2, UR3, and UR4 about subequally distant; basal articulation of seta UR8 inserted apically on urogomphomere 2 (Uro2'/Uro2 = 1.00). Description, Second-instar Larva. As first-instar larva except for the following characters: Colour. Cephalic capsule with an irrorate creamy white pattern posteriorly; thorax, pro- and mesoterga with a piceous macula along anterior margin and medially respectively. Head. HL = 0.57-0.63 mm; HW = 0.56-60 mm; FCL = 0.43-46 mm; HL/HW = 1.02-1.07; cephalic capsule, FCLIFCW = 1.93-2.07; lateral margin of parietale with six to eight bluntly rounded and strong temporal spines; head appendages, length of antenna/HW = 0.60-0.63; A2/A3 = 0.74-0.83; labial palpomere 2, 1.03- 1.15 times length of labial palpomere 1. Legs. Metathoracic legs 1.30 times length of prothoracic legs; position and number of secondary setae as expressed in Table 2; posterior metatarsal claw 0.60-0.77 times length of metatarsus. Abdomen. LLAS = 0.18-0.21 mm; siphon, 0.17-0.28 times LLAS; abdomen seg- ment 7 with one pair of bluntly rounded secondary setae on lateral margin; abdomen segment 8 with two or three pairs of bluntly rounded secondary setae. Urogomphus (Fig. 79). Total length of urogomphus = 1.13-1.25 mm (length of urogomphomere 1 = 0.70-0.80 mm); urogomphus 1.90-2.08 times HW (length of UrolLHW = 1.18- 1.29), and 5.45-6.51 times LLAS (length of Urol/LLAS = 3.40-4.07); urogomphomere 1 with bluntly rounded secondary setae present (Fig. 79) or absent; Urol/Uro2 = 1.57-1.79 (UrolKJro2' = 1.57-1.79). Description, Third-instar Larva (Figs. 35, 58,59,72,78). As second-instar larva except for the following characters: Colour. Head appendages creamy white, except apex of antennomere 4, apex of maxillary palpomere 3, and apex of labial palpomere 2 lightly infuscate; thorax, protergum predominantly yellowish with a blackish stripe laterally, mesotergum yellowish laterally, blackish medially, metatergum black with a lateral greyish stripe; legs predominantly creamy white; abdomen, terga 1,2, and 6 predominantly black with a medial and lateral yellowish 412 THE CANADIAN ENTOMOLOGIST MayIJune 1997 brown macula on each side; terga 3-5 and 7 predominantly yellowish with a few piceous maculae, tergum 8 yellowish brown anteriorly, black posteriorly; urogomphus, urogom- phomere 1 yellowish, urogomphomere 2 pale grey. Head (Figs. 35). HL = 0.80-0.82 rnm; HW = 0.77-0.81 mm; FCL = 0.58-0.60 mm; cephalic capsule, FCLIFCW = 1.86-2.05; lateral margin of parietale with 9- 13 temporal spines; antenna, A2/A3 = 0.88-0.97; A3'/A4 = 0.38-0.43; maxilla, length of antennallength of maxillary palpus = 0.89-1.09; palpomere 2, 0.86-0.92 times length of palpomere 1; labium, length of maxillary palpus/length of labial palpus = 1.26-1.29; palpomere 2,0.78-0.89 times as long as palpomere 1. Legs (Figs. 58, 59). Position and number of secondary setae as expressed in Table 4; posterior metatarsal claw 0.5 1-0.57 times length of metatarsus. Abdomen (Fig. 72). MBW/LASW = 3.75; LLAS = 0.26-0.27 mm; LLAS/HW = 0.32-0.34; siphon slightly shorter than in second-instar larva, 0.08-0.15 times LLAS. Urogomphus (Fig. 78). Total length of urogomphus =not determined (this value is not calculated because primary seta UR8 cannot be distinguished from urogomphomere 2) (length of urogomphomere 1 = 0.91 - 1.01 mm), length of urogomphomere 1/HW = 1.13- 1.28; length of UrolLLAS = 3.43-3.81; Urol/Uro2 = not determined (Urol/Uro2' = not determined). Taxonomic Notes. The 0.picturatus species-group comprises two unique species within Oreodytes: 0.picturatus and 0.angustior. Both species are characterized by the presence of bluntly rounded secondary setae over some parts of their body (Figs. 35,72,79) as well as by the terminal position of primary seta UR8 on urogomphomere 2 (Figs. 76,78,79). The latter feature is surprising as until now this character state was known to occur only in the genus Laccornis Gozis which has been considered the sister-group of the subfamily Hydro- porinae (Alarie 1989; Alarie and Harper 1990). It is noteworthy that Guignot (1945) proposed 0.picturatus as the type species of the genus Deuteronectes Guignot based on adult morphology which might substantiate a different placement of members of the 0.picturatus species-group within Oreodytes. Members of the 0.picturatus species-group may be confounded superficially with those of the 0.obesus species-group as a result of their small size, slightly broader body size, and presence of deeply grooved microsculpture over the cephalic capsule. However, both 0.picturatus and 0.angustior may easily be distinguished by several features including a narrower body shape, the presence of spinulae on the ventral margin of the tibiae and tarsi, the presence of an additional pore on urogomphomere 1, and a more elongate urogomphus.

KEY TO SPECIES OF THE OREODYTES PICTURATUS SPECIES-GROUP 1. Frontoclypeus with egg-bursters (Fig. 1) (first instar) ...... 0.picturatus and 0.angustior - Frontoclypeus lacking egg-bursters (Fig. 35) (second or third instar) ...... 2

2. Urogomphomere 1 lacking bluntly rounded secondary setae (Fig. 78); abdomen segment 8 generally with three pairs of bluntly rounded secondary setae (Fig. 72) ...... 0.picturatus - Urogomphomere 1 with several bluntly rounded secondary setae (Fig. 79); abdomen segment 8 with two pairs of bluntly rounded secondary setae...... 0. angustior

Oreodytespicturatus (Horn) (Figs. 1,2, 16,35,58,59,66,72,76,78) Diagnostic Combination. Abdomen segment 8 generally with three pairs of bluntly rounded secondary setae (Fig. 72); urogomphomere 1 lacking bluntly rounded secondary setae (Fig. 78). Description, First-instar Larva (Figs. 1,2, 16,66,76). Volume 129 THE CANADIAN ENTOMOLOGIST 413 Colour. As for the description of the species-group. Head(Figs. 1,2,16).HL=0.44-0.48mm(Y =0.46mm,n=4); HW=0.43-0.46mm (Y = 0.44 mm, n = 4); FCL= 0.34-0.36 mm (Y = 0.34 mm, n = 4); cephalic capsule (Figs. 1, 2) slightly longer than broad (HL/HW = 0.99-1.08), with neck constriction distinctly delimited (HW/OcW = 1.65- 1.86); FCLFCW = 1.83-2.07); antenna (Fig. 16), length of antenna/HW = 0.70-0.73; A2/A3 = 0.74-0.81; A3'/A4 = 0.25-0.27; maxilla, length of antennallength of maxillary palpus = 1.29- 1.32; labium, length of maxillary palpusllength of labial palpus = 1.11- 1.16; palpomere 2, 1.37- 1.65 times length of palpomere 1. Legs. Posterior metathoracic claw about 0.75-0.78 times as long as metatarsus; length of longest between setae FE8 and FE9/width of metafemur = 1.09-1.22; length of seta TI4lwidth of metatibia = 1.84-2.00; length of seta TA2/width of metatarsus = 1.14-1.29. Abdomen (Fig. 66). MBW/LASW= 3.57; LLAS = 0.14-0.17 mm (F = 0.15 mm, n = 4); LLAS/HW = 0.31 -0.36; siphon acute apically, about 0.26-0.43 times LLAS; length of seta ABllLLAS = 0.63-0.70. Urogomphus (Fig. 76). Total length of urogomphus = 0.82-0.89 mm (T = 0.85 mm, n = 4) [length of urogomphomere 1 = 0.55-0.58 mm (Y = 0.57 mm, n = 4)]; 1.88- 1.98 times HW (length of Urol/HW = 1.26-1.33), and 5.85-6.32 times LLAS (length of UrolILLAS = 3.92-4.17); Urol/Uro2 = 1.94-2.13 (Urol/Uro2' = 1.94-2.13 (range of values are identical with the previous one as seta UR8 is inserted apically). Description, Second-instar Larva. As first-instar larva except for the following characters: Head. HL = 0.60-0.63 mm (Y = 0.62 mm, n = 4); HW = 0.58-60 mm (Y = 0.59 mm, n = 4); FCL = 0.45-46 mm (T = 0.46 mm, n = 4); HLJHW = 1.02- 1.07; cephalic capsule, FCLFCW = 1.98-2.07; lateral margin of parietale with six to eight bluntly rounded strong temporal spines; head appendages, length of antenna/HW = 0.60-0.63; A2/A3 = 0.74- 0.82; labial palpomere 2, 1.03- 1.15 times length of labial palpomere 1. Legs. Metathoracic legs 1.30 times length of prothoracic legs; position and number of secondary setae as expressed in Table 2; posterior metatarsal claw 0.60-0.67 times length of metatarsus. Abdomen. LLAS = 0.18-0.20 mm (Y = 0.19 mm, n = 6); siphon, 0.17-0.28 times LLAS; abdomen segment 7 with one pair of bluntly rounded secondary setae on lateral margin; abdomen segment 8 with three pairs of bluntly rounded secondary setae. Urogomphus. Total length of urogomphus = 1.13- 1.25 mm (Y = 1.15 mm, n = 6) [length of urogomphomere 1 = 0.70-0.80 mm (F = 0.76 mm, n = 6)]; urogomphus 1.90-2.08 times HW (length of Urol/HW = 1.18-1.29), and 5.98-6.51 times LLAS (length of UrolILLAS = 3.79-4.07); urogomphomere 1 with bluntly rounded secondary setae absent; UrolKJro2 = 1.57-1.79 (Urol/Uro2' = 1.57- 1.79). Description, Third-instar Larva (Figs. 35,58, 59,72,78). As second-instar lama except for the following characters: Head (Fig. 35). HL = 0.80-0.82 mm (F = 0.82 mm, n = 4); HW = 0.77-0.81 mm (T = 0.79 mm, n = 4); FCL = 0.58-0.60 mm (T = 0.59 mm, n = 4); cephalic capsule (Fig. 33, FCL/FCW = 1.86-2.05; lateral margin of parietale with 9-13 temporal spines; antenna, A2/A3 = 0.88-0.97; A3'/A4 = 0.38-0.43; maxilla, length of antennahength of maxillary palpus = 0.89- 1.09;palpomere 2,0.86-0.92 times length of palpomere 1; labium, length of maxillary palpusfiength of labial palpus = 1.26-1.29; palpomere 2, 0.78-0.89 times as long as palpomere 1. Legs (Figs. 58, 59). Position and number of secondary setae as expressed in Table 4; posterior metatarsal claw 0.51 -0.57 times length of metatarsus. Abdomen (Fig. 72). MBWKASW = 3.75; LLAS = 0.26-0.27 mm (Y = 0.26 rnm, n = 4); LLAS/HW = 0.32-0.34; siphon slightly shorter than in second-instar larva, 0.08- 0.15 times LLAS. 414 THE CANADIAN E?4TOMOLOGIST MayIJune 1997 Urogomphus (Fig. 78). Total length of urogomphus not determined (this value was not calculated because primary seta UR8 cannot be distinguished from urogomphomere 2), [length of urogomphomere 1 = 0.91 - 1.01 mm (F = 0.95 mm, n = 4)]; length of urogom- phomere 1/HW = 1.13- 1.28; length of Urol/LLAS = 3.43-3.81; Urol/Uro2 = not deter- mined (Urol/Uro2' = not determined). Source of Reared or Associated Material. Eggs were obtained from adults collected at the following locality: USA. California. Humboldt Co., Redwood Ck, Hwy 101 in Orick, 21 .V. 1994 and 26.V.1995. Taxonomic Notes. The larvae of 0.picturatus are very similar morphologically to those of 0. angustior. The only reliable character discovered for distinguishing the species is the presence of several bluntly rounded secondary setae on the urogomphus of 0. angustior which are lacking in 0.picturatus. Oreodytes picturatus also differs from 0. angustior by the presence generally of three pairs of bluntly rounded secondary setae on abdomen segment 8 (compared with two) as well as by the presence of at least 11 secondary setae on the metafemur (instead of eight or nine in 0. angustior). However, both these characteristics should be used cautiously as only one specimen of 0. angustior was available for study. Distribution. This species is very common in northern California. Zimmerman (1985) reported records from western Nevada, Idaho, Oregon, and British Columbia.

Oreodytes angustior (Hatch) (Fig. 79) Diagnostic Combination. Abdomen segment 8 with two pairs of bluntly rounded secondary setae; urogomphomere 1 with several bluntly rounded secondary setae (Fig. 79). Description, First-instar Larva. No specimen of the first-instar larva was available for description. Description, Second-instar Larva (Fig. 79). Colour. Cephalic capsule predominantly greyish black except apically over fronto- clypeus, laterally over parietale and ocularium, and around egg-bursters creamy white; head appendages creamy white, except antennomere 4, apex of antennomere 3, maxillary palpomere 3, apex of maxillary palpomere 2 infuscate; thorax, pro- and mesothoracic terga creamy white to pale yellow, metathoracic tergum greyish black; legs predominantly creamy white; abdomen, terga 1, 7, and 8 greyish black, terga 2-6 creamy white to pale yellow; urogomphi creamy white to pale yellow. Head. HL = 0.57 mm (n = 1); HW = 0.56 mm (n = 1); FCL = 0.43 mm (n = 1); cephalic capsule, HL/HW = 1.02, FCL/FCW = 1.93; lateral margin of parietale with six bluntly rounded strong temporal spines; head appendages, length of antenna/HW = 0.63; A2/A3 = 0.83; labial palpomere 2, 1.10 times length of labial palpomere 1. Legs. Metathoracic legs 1.30 times length of prothoracic legs; position and number of secondary setae as expressed in Table 2; posterior metatarsal claw 0.77 times length of metatarsus. Abdomen. LLAS = 0.21 mm (n = 1); siphon, 0.27 times LLAS; abdomen segment 7 with one pair of bluntly rounded secondary setae on lateral margin; abdomen segment 8 with two pairs of bluntly rounded secondary setae. Urogomphus (Fig. 79). Total length of urogomphus = 1.13 mm (n = 1) [length of urogomphomere 1 = 0.70 mm (n = I)]; urogomphus 2.01 times HW (length of Urol/HW = 1.25), and 5.45 times LLAS (length of Urol/LLAS = 3.40); urogomphomere 1 with a few bluntly rounded secondary setae present (Fig. 79); Urol/Uro2 = 1.63 (Urol/Uro2' = 1.63). Volume 129 THE CANADIAN ENTOMOLOGIST 415 Description, Third-instar Larva. No specimen of the third-instar larva was available for description. Source of Reared or Associated Material. Eggs were obtained from adults collected at the following locality: CANADA. British Columbia. Duteau Ck, 5 krn W Lumby, Hwy 6, 3 1.V. 1992. Taxonomic Notes. See under 0.picturatus. Distribution. This species is known from southern British Columbia, northern Idaho, Washington, and western Oregon.

THEOREODYTES SCZTULUS SPECIES-GROUP (Figs. 17-19,21-26,36-43,56,57,64,69,73,80) This species-group corresponds to the scitulus species-group of Zimmerman (1985). It contains the largest species of the genus Oreodytes. Diagnostic Combination. Body narrow, MBWJLASW < 3.80; lamellae clypeales inter- rupted medially for a short distance (Fig. 1); antennomere 3 with pore ANf absent (Figs. 21 - 26); primary seta AN2 inserted subapically, either lower or at about level of ventral spinula (Figs. 21 -26); temporal spines of a normal shape (i.e. acute apically) and strongly developed (Figs. 36-43); spinulae present on ventral margin of tibiae and tarsi (Figs. 56,57); abdomen segments 7 and 8 lacking bluntly rounded secondary setae (Fig. 69); primary seta AB5 short, not extending beyond apex of siphon (Fig. 64); urogomphus elongate, more than 1.90 times HW (urogomphomere 1 more than 1.10 times longer than HW) (Figs. 73, 80); urogom- phomere 1 at least 1.70 times longer than urogomphomere 2, with an additional pore (Fig. 73), lacking bluntly rounded secondary setae (Fig. 80); primary setae UR2, UR3, and UR4 about subequally distant, setae UR2 and UR3 inserted dorsolaterally and ventrally respectively (Fig. 73); primary seta UR8 inserted subapically on urogomphomere 2 (Uro2'/Uro2 > 0.70, in first-instar larva) (Fig. 73). Description, First-instar Larva (Figs. 17- 19,21-26,64,73). Colour. Cephalic capsule, dorsal surface predominantly greyish black to predomi- nantly creamy white, consistently greyish black posteriorly over parietale and occipital region; head appendages, predominantly greyish black to predominantly creamy white to pale yellow; thorax, protergum yellowish or greyish black, meso- and metaterga greyish black; legs, predominantly greyish black to predominantly creamy white; abdomen, terga yellowish grey to blackish; urogomphus, predominantly creamy white to predominantly blackish. Head (Figs. 17-19, 21-26). HL = 0.55-0.69 mm; HW = 0.47-0.63 mm; FCL = 0.41-0.54 mm; cephalic capsule (Figs. 21-26) slightly longer than broad (HL/HW = 1.02- 1.17), with neck constriction distinctly delimited (HW/OcW = 1.5 1- 1.98); FCLIFCW = 1.91-2.38; frontoclypeus with side at most slightly sinuate at level of lateral notches; lamellae clypeales interrupted medially for a short distance (Fig. 1); antenna (Figs. 17- 19), length of antenna/HW = 0.77-0.83; A2/A3 = 0.81-0.91; A3'1A4 = 0.24-0.51; pore ANf lacking and seta AN2 inserted subapically, either lower or at about same level of spinula, on antennomere 3; maxilla, length of antenndength of maxillary palpus = 1.32-1.56; setae MX2, MX3, and MX4 short; maxillary stipes lacking additional seta; labium, length of maxillary palpusllength of labial palpus = 1.04- 1.15; palpomere 2, 1.09- 1.42 times length of palpomere 1. Legs. Metathoracic legs about 1.30 times length of prothoracic legs, and 2.57-2.98 times HW, posterior metathoracic claw about 0.67-0.88 times length of metatarsus; spinulae present on ventral margin of tibiae and tarsi; length of longest between setae FE8 and 416 THE CANADIAN ENTOMOLOGIST May/June 1997 FE9lwidth of metafemur = 0.82-1.50; length of seta TI4/width of metatibia = 1.37-2.16; length of seta TA2lwidth of metatarsus = 0.95-1.63. Abdomen (Fig. 64). MBWLASW = 2.89-3.75; LLAS = 0.15-0.21 mm; LLAS/HW = 0.29-0.34; siphon broadly rounded apically, about 0.34-0.45 times LLAS; primary seta AB5 short, not extending beyond apex of siphon; length of seta AB111LLAS = 0.50-0.61. Urogomphus (Fig. 73). Total length of urogomphus = 1.02-1.43 mm (length of urogomphomere 1 = 0.64-0.97 mm); 1.96-2.55 times HW (length of Urol/HW = 1.20- 1.68), and 6.29-7.80 times LLAS (length of UrolLLAS = 3.90-5.28); UrolKJro2 = 1.43-2.39 (Urol/Uro2' = 1.83-2.87); urogomphomere 1 with one additional pore; primary setae UR2 and UR3 inserted dorsolaterally and ventrally respectively; basal articulations of primary setae UR2, UR3, and UR4 nearly subequally distant; basal articulation of seta UR8 inserted apically on urogomphomere 2 (Uro2'/Uro2 = 0.78-0.82). Description, Second-instar Larva. As first-instar larva except for the following char- acters: Head. HL = 0.77-0.97 mm; HW = 0.70-0.89 mm; FCL = 0.56-0.76 mm; HLIHW = 1.05- 1.12; cephalic capsule, FCLIFCW = 1.99-2.46; lateral margin of parietale with four to nine strong temporal spines acute apically; head appendages, antenna, length of antenna/HW = 0.66-0.69; A2/A3 = 0.92-1.06; A3'/A4 = 0.23-0.55; labium, labial palpomere 2,0.90- 1.OO times length of labial palpomere 1. Legs. Metathoracic legs 1.30-1.40 times length of prothoracic legs; position and number of secondary setae as expressed in Table 2; posterior metatarsal claw 0.52-0.76 times length of metatarsus. Abdomen. LLAS = 0.24-0.34 mm; siphon, 0.20-0.24 times LLAS; abdomen seg- ments 7 and 8 lacking bluntly rounded secondary setae. Urogomphus. Total length of urogomphus = 1.47-2.20 mm (length of urogom- phomere 1 = 0.92-1.52 mm); urogomphus 1.99-2.49 times HW (length of UrolIHW = 1.21-1.75), and 5.70-7.16 times LLAS (length of UrolLLAS = 3.79-4.75); urogom- phomere 1 lacking bluntly rounded secondary setae; Urol/Uro2 = 1.81-2.36 (UrolIUro2' = 1.97-2.60). Description, Third-instar Larva (Figs. 36-43, 56, 57, 69, 80). As second-instar larva except for the following characters: Colour. Cephalic capsule, dorsal surface more predominantly creamy white; head appendages, predominantly creamy white to pale yellow, distal articles generally infuscate apically; thorax, protergum yellowish or greyish black, meso- and metaterga predominantly yellowish to pale grey; legs, predominantly creamy white. Head (Figs. 36-43). HL = 1.01-1.35 mm; HW = 0.95-1.30 mm; FCL = 0.81- 1.03 mm; cephalic capsule (Figs. 36-43), FCLJFCW = 1.91-2.48; lateral margin of parietale with 8-20 temporal spines; antenna, A2/A3 = 1.05- 1.19; A3'1A4 = 0.29-0.56; maxilla, length of antennapength of maxillary palpus = 1.23- 1.29; palpomere 2,0.70-0.90 times length of palpomere 1; labium, length of maxillary palpus/length of labial palpus = 1.05- 1.12; palpomere 2,0.70-0.80 times as long as palpomere 1. Legs (Figs. 56, 57). Position and number of secondary setae as expressed in Table 4; posterior metatarsal claw 0.47-0.70 times length of metatarsus. Abdomen (Fig. 69). MBWLASW = 2.33-3.29; LLAS = 0.36-0.53 mm; LLAS/HW = 0.36-0.47; siphon, 0.09-0.18 times LLAS. Urogomphus (Fig. 80). Total length of urogomphus = 1.84-2.91 mm (length of urogomphomere 1 = 1.22-2.02 mm), urogomphus 1.86-2.86 times HW (length of urogom- phomere l/HW = 1.36-1.93), and 4.92-6.08 times LLAS (length of UrolLLAS = 3.48- 4.21); Urol/Uro2 = 1.66-2.59 (UrolKJro2' = 1.64-2.76). Volume 129 THE CANADIAN ENTOMOLOGIS~ 417 Source of Reared or Associated Material. The 0.scitulus species-group comprises fairly similar species which may be readily recognized by their larger size, narrower body shape, elongate urogomphus, absence of deeply grooved microsculpture dorsally over the cephalic capsule, and the presence of spinulae along the ventral margin of the tibiae and tarsi. Members of this species-group may also be subdivided into two groups based on pres- encelabsence of secondary setae on the tarsi.

KEY TO THE KNOWN SPECIES OF THE OREODYTES SCZTULUS SPECIES-GROUP

Key to First-instar Larvae 1. Lateral elongation of antennomere 3 elongate, A3'/A4 > 0.35 (Fig. 17); ratio FCL/FCW < 2.10 (Figs. 21,22) ...... 0.scitulus - Lateral elongation of antennomere 3 shorter, A3'/A4 < 0.30 (Figs. 18, 19); ratio FCL/FCW > 2.20 (Figs. 23-26)...... 2

2. Primary seta TI4 of metabia elongate, more than 2.00 times longer than maximum width of metatibia...... 0.snoqualmie - Primary seta TI4 of metabia shorter, less than 1.90 times longer than maximum width of metatibia ...... 3

3. Basal articulation of primary seta AN2, on antennomere 3, located at about level of ventroapical spinula (Fig. 18)...... 0. recticollis - Basal articulation of primary seta AN2, on antennomere 3, located more medially, distinctly lower than ventroapical spinula (Fig. 19) ...... 4

4. Larger species, HL 2 0.65 mm (Fig. 25) ...... 0.productotruncatus - Smaller species, HL 5 0.61 mm (Fig. 24) ...... 0.laevis

Key to Second- and Third-instar Larvae 1. Pro- and mesotarsi with at least one secondary seta (Figs. 56,57)...... 2 - Pro- and mesotarsi lacking secondary setae ...... 6

2. Tarsi lacking secondary setae along dorsal margin; urogomphomere 1, in third-instarlarva shorter, less than 1.60 times longer than HW, and less than 2.20 times longer than Uro2' ...... 0.recticollis - Tarsi with at least one secondary seta on dorsal margin (Figs. 56, 57); urogomphomere 1, in third-instar larva longer, more than 1.60 times longer than HW, and more than 2.20 times longer thanUr02' ...... 3

3. Mesothorax and abdominal segments 1-7 lacking spiracular openings (second-instar larva) . 4 - Mesothorax and abdominal segments 1-7 with spiracular openings present (third-instar larva) ...... 5

4. Coxae lacking anterior secondary setae; urogomphomere 1 longer, more than 4.40 times longer than LLAS ...... 0.snoqualmie - Coxae with at least one anterior secondary seta (Figs. 57,58); urogomphomere 1 shorter, less than 4.40 times longer than LLAS...... 0.laevis

5. Metatrochanterwith at most two secondary setae; urogomphomere 1 longer, more than 4.00 times longer than LLAS (Fig. 73)...... 0.snoqualmie - Metatrochanter with at least three secondary setae (Figs. 54,55); urogomphomere 1 shorter, less than 4.00 times longer than LLAS...... 0.laevis

6. Mesothorax and abdominal segments 1-7 lacking spiracular openings (second-instar larva). .. 7 418 THE CANADIAN ENTOMOLOGIST MayIJune 1997 - Mesothorax and abdominal segments 1-7 with spiracular openings present (third-instar larva) ...... 9

7. Pro- and metacoxae with at most six and eight secondary setae respectively; lateral elongation of antennomere 3 longer, A3'1A4 r 0.38; urogomphomere 1 shorter, less than 1.40 times longer than HW, smaller species, HL 5 0.84 mrn ...... 0.scitulus - Pro- and metacoxae with at least nine secondary setae; lateral elongation of antennomere 3 shorter, A3'/A4 5 0.30; urogomphomere 1 longer, more than 1.SO times longer than HW, larger species, HL20.90mm ...... 8 8. Ratio Urol/Uro2' 5 2.03; western Alberta, southeastern British Columbia, and western Montana ...... 0.productotruncatus - Ratio Urol/Uro2' 2 2.17; coastal Alaska, British Columbia, and Washington ... 0.alaskanus

9. Pro-, meso-, and metacoxae with at most 13, 14, and 15 secondary setae respectively; posterior metatarsal claw shorter, less than 0.50 times longer than length of metatarsus; smaller species, HL 5 1.17 mm...... 0. scitulus - Pro-, meso-, and metacoxae with at least 15, 15, and 16 secondary setae respectively; posterior metatarsal claw longer, more than 0.55 times longer than length of metatarsus; larger species, HL 2 1.18 mm...... 10

10. Ratio Urol/Uro2' 5 2.10; western Alberta, southeastern British Columbia, and western Montana ...... 0.productotruncatus - Ratio Urol/Uro2' 2 2.10; coastal Alaska, British Columbia, and Washington ... 0.alaskanus

Oreodytes scitulus (LeConte) (Figs. 17,21,22,38,39,69)

Diagnostic Combination. Lateral elongation of antennomere 3 longer, A3'/A4 generally more than 0.40; basal articulation of the primary seta AN2 inserted more medially on antennomere 3, below anteroventral spinula (first-instarlarva); coxae, in second-instarlarva, with anterior secondary setae present or absent; primary seta TI4 short, less than 1.90 times longer than maximum width of metatibia in first-instar larva; pro- and mesotarsi of second- and third-instar larvae lacking secondary setae; smaller species. Redescription, First-instar Larva (Figs. 17,21,22). Colour. Cephalic capsule (Figs. 21, 22), dorsal surface creamy white anteriorly and laterally, black over parietale and occipital region; head appendages predominantly creamy white except antennomere 4, apex of antennomere 3, apex of maxillary palpomere 3, and apex of labial palpomere 2 infuscate; thorax, protergum testaceous, meso- and metaterga greyish; legs, creamy white; abdomen, terga 1-4 creamy white to pale yellow, terga 5-8 greyish black; urogomphus, predominantly creamy white to yellowish, greyish black apically for a short distance both on urogomphomere 1 and 2. Head (Figs. 21,22). HL = 0.55-0.59 mm (T = 0.57 mm, n = 9); HW = 0.52-0.55 mm (Y = 0.54 mm, n = 9); FCL= 0.41 -0.44 mm (T = 0.43 mm, n = 9); cephalic capsule, HL/HW = 1.02- 1.11, HW/OcW = 1.68- 1.98; FCLFCW = 1.91-2.08; antenna (Fig. 17), A3'/A4 = 0.33-0.51; antennomere 3 with seta AN2 inserted subapically, lower than spinula; labium, palpomere 2, 1.09- 1.32 times length of palpomere 1. Legs. Metathoracic legs about 2.60 times HW; posterior metathoracic claw about 0.67-0.75 times length of metatarsus; length of longest between setae FE8 and FE9lwidth of metafemur = 0.82- 1.21; length of seta TI4/width of metatibia = 1.37- 1.83; length of seta TA2lwidth of metatarsus = 0.95- 1.31. Abdomen. MBW/LASW = 3.75; LLAS = 0.15-0.17 mm (T = 0.16 mm, n = 9). Urogomphus. Total length of urogomphus = 1.02- 1.20 mm (Y = 1.13 mm, n = 9) [length of urogomphomere 1 = 0.64-0.81 mm (Y = 0.72 rnm, n = 9)]; 1.96-2.25 times HW (length Volume 129 THE CANADIAN EhTOMOLOGIST 419 of Urol/HW= 1.20- 1.47), and 6.52-7.81 times LLAS (length of UrolLLAS = 3.90-5.28); Uro11Uro2 = 1.43-2.10 (Urol/Uro2' = 1.83-2.72). Redescription, Second-instar Larva. As first-instar larva except for the following characters: Colour. Cephalic capsule more predominantly creamy white; apex of labial palpomere 2 black; abdomen, tergum 7 predominantly yellowish; urogomphus, urogom- phomere 2 blackish. Head. HL = 0.77-0.84 mm (T = 0.79 mm, n = 8); HW = 0.70-0.79 mm @ = 0.74 mm, n = 8); FCL= 0.56-0.64 mm (T = 0.60 mm, n = 8); cephalic capsule, FCLIFCW = 1.99-2.13; lateral margin of parietale with six to nine temporal spines; antenna, A3'1A4 = 0.38-0.55. Legs. Position and number of secondary setae as expressed in Tables 2 and 8; posterior metatarsal claw 0.52-0.59 times length of metatarsus. Abdomen. LLAS = 0.24-0.27 mm (Y = 0.25 mm, n = 9). Urogomphus. Total length of urogomphus = 1.47- 1.72 mm (Y = 1.59 mm, n = 9) [length of urogomphomere 1 = 0.92- 1.16 mm (Y = 1.05 mm, n = 9)]; urogomphus 1.99-2.17 times HW (length of Urol/HW = 1.21- 1.40), and 5.70-7.16 times LLAS (length of UrolLLAS = 3.79-4.75); Urol/Uro2 = 1.82-1.96 (Urol/Uro2'= 1.98-2.35). Redescription, Third-instar Larva (Figs. 38,39,69). As second-instar larva except for the following characters: Colour. Thorax, terga predominantly creamy white to pale grey, with a few paler yellowish maculae; abdomen, terga 1-4 and 7 predominantly creamy white, with a few pale grey maculae laterally, terga 5 and 6 predominantly greyish black with two yellowish maculae medially, tergum 8 greyish black, yellowish along anterior margin. Head(Figs.38,39).HL=1.01-1.17mm(Y=1.09mm,n=12);HW=0.99-1.11mm (Y = 1.05 mm, n = 12); FCL = 0.81-0.89 mm (Y = 0.84 mm, n = 12); cephalic capsule, FCLJFCW = 1.91-2.20; lateral margin of parietale with 10-20 temporal spines; antenna, A3'/A4 = 0.41 -0.56. Legs. Position and number of secondary setae as expressed in Tables 4 and 8; posterior metatarsal claw 0.45-0.50 times length of metatarsus. Abdomen (Fig. 69). MBWLASW = 3.29; LLAS = 0.36-0.39 mm (T = 0.38 mm, n = 12). Urogomphus. Total length of urogomphus = 1.84-2.61 mm (Y = 2.22 mm, n = 12) [length of urogomphomere 1 = 1.22- 1.69 mm (T = 1.42 mm, n = 12)]; urogomphus 1.86-2.42 times HW (length of urogomphomere 1/HW = 1.23- 1.57), and 5.17-6.08 times LLAS (length of UrolLLAS = 3.65-4.21); Urol/Uro2 = 1.66-2.06 (Urol/Uro2'= 1.64- 2.18). Source of Reared or Associated Material. Eggs were obtained from adults collected at the following localities: CANADA. British Columbia. Keremeos, Similkameen River, 30.V. 1992; USA. California. Humboltd Co., Redwood Ck, Hwy 101 in Orick, 21 .V. 1994 and 26.V.1995; Washington. Pierce Co., Carbon River at Hwy 162, 14 km W Buckley, 29.V.1995. Additional larval specimens were obtained in association with adults at the following locality: CANADA. Quebec. Sutton Co., Yamaska River at Hwy 215, 6 km S Brome, 23.VI. 1989. Taxonomic Notes. Larvae of 0.scitulus may be readily distinguished from other members of the 0.scitulus species-group by several features including the smaller size, the relatively more elongate A3', and the absence of secondary setae on the tarsi. In his revision of the North American species of Oreodytes, Zimmerman (1985) divided the 0.scitulus-complex into two subspecies: 0.scitulus scitulus (LeConte) and 0.scitulus bisulcatus (Fall). Geographically, the aggregate distribution of the two subspecies is very extensive within North America ranging from ocean to ocean in Canada and the northern 420 THE C..INADlAN ENTOMOLOGIST MayIJune 1997 United States, and extending southward in the west to New Mexico. For this study, I have been fortunate to rear larvae of selected populations of 0.scitulus among which are a few representatives of both subspecies. Tables 6 and 7 show selected measurements and ratios of larval structures for each population. Although such comparison is hampered by the low number of specimens studied, it seems obvious that these larvae are very similar morpho- logically. The only differences observed among larvae were the longer urogomphi of British Columbian specimens and the slightly larger size of the cephalic capsule of both the Californian and British Columbian ones. A close similarity between those larvae is also confirmed by leg chaetotaxy (Table 8) where no significant differences may be reported in regard to the number and position of secondary setae among the specimens studied. Accordingly, based on larval morphology, subspecies of 0.scitulus cannot be recognized. One additional problem with 0. scitulus is its relationship with the Palearctic species 0.septentrionalis as it has been suggested that both species might be conspecific (Nilsson 1987b). The larvae of 0. septentrionalis appear to be fairly similar morphologically to 0. scitulus. Both species are characterized by their small size, absence of secondary setae on the tarsi, and the lesser value of the ratio FCL/FCW. Based on a morphometric comparison (Tables 6 and 7), larvae of 0.septentrionalis differ from those of 0.scitulus by the relatively smaller size (although this has been observed for the first- and third-instar larvae only) as well as the shorter length of the lateral elongation of antennomere 3 (A3'). Study of additional larval specimens would be needed to know whether or not these two differences are consistent for the recognition of the taxonomic status of 0. septentrionalis. Distribution. This species occurs across northern North America, from Newfoundland and New York to British Columbia and California.

Oreodytes laevis (Kirby) (Figs. 24,36,37,56,57) Diagnostic Combination. Lateral elongation of antennomere 3 shorter, A3'/A4 generally less than 0.40; basal articulation of the primary seta AN2 inserted more medially on antennomere 3, below anteroventral spinula (first-instar larva); coxae, in second-instarlarva, with anterior secondary setae present; primary seta TI4 short, less than 1.90 times longer than maximum width of metatibia in first-instar larva; pro- and mesotarsi of second- and third-instar larvae with secondary setae on both ventral and dorsal margins; medium-size species. Description, First-instar Larva (Fig. 24). Colour. Cephalic capsule, dorsal surface predominantly creamy white except over basal half of parietale and occipital region greyish black; head appendages, creamy white, except antennomere 4, apex of antennomere 3, apex of maxillary palpomere 3, and apex of labial palpomere 2 lightly infuscate; thorax, terga predominantly yellowish to pale grey; legs, creamy white proximally over coxae, trochanter, and femora, pale grey otherwise; abdomen, terga predominantly yellowish to pale grey, increasingly darker over posterior segments; urogomphus, predominantly greyish black, creamy white over proximal portion of urogomphomere 1. Head (Fig. 24). HL = 0.55-0.61 mm (F = 0.59 mm, n = 6); HW = 0.47-0.57 mm (F = 0.55 mm, n = 6); FCL= 0.41 -0.48 mm (T = 0.46 rnm, n = 6); cephalic capsule (Fig. 24), HL/HW = 1.04-1.17, HW/OcW = 1.50-1.64; FCL/FCW = 2.15-2.36; antenna, A3'/A4 = 0.26-0.32; antennomere 3 with seta AN2 inserted subapically, lower than spinula; labium, palpomere 2, 1.32- 1.48 times length of palpomere 1. Legs. Metathoracic legs about 2.90 times HW; posterior metathoracic claw about 0.85-0.88 times length of metatarsus; length of longest between setae FE8 and FE9Jwidth Volume 129 THE CANADIAN ENTOMOLOGIST 42 1 of metafemur = 1.05- 1.16; length of seta TI4Jwidth of metatibia = 1.43- 1.83; length of seta TA2Jwidth of metatarsus = 1.08- 1.56. Abdomen. MBWLASW = 3.22; LLAS = 0.17-0.19 mm (T = 0.18 mm, n = 6). Urogomphus. Total length of urogomphus = 1.18- 1.34 mm (T = 1.28 mm, n = 6) [length of urogomphomere 1 = 0.78-0.88 mm (Y = 0.85 mm, n = 6)]; 2.22-2.55 times HW (length of Urol/HW= 1.50-1.68), and6.61-7.13 times LLAS (length of UrolLLAS =4.56-4.71); Urol/Uro2 = 1.91-2.22 (Urol/Uro2' = 2.29-2.87). Description, Second-instar Larva. As first-instar larva except for the following characters: Colour. Cephalic capsule more predominantly creamy white, generally with a V-shaped black dorsal pattern along coronal suture (some specimens were found to be more broadly infuscate posteriorly over parietale); thorax, terga with a few yellowish maculae; legs, femur predominantly creamy white. Head. HL= 0.79-0.85 mm (F = 0.82 mm, n = 5); HW = 0.73-0.81 mm (T = 0.77 mm, n = 5); FCL= 0.61 -0.66 mm Q = 0.64 mm, n = 5); cephalic capsule, FCLRCW = 2.24-2.45; lateral margin of parietale with four to six temporal spines; antenna, A3'/A4 = 0.27-0.33. Legs. Position and number of secondary setae as expressed in Table 2; posterior metatarsal claw 0.70-0.76 times length of metatarsus. Abdomen. LLAS = 0.28-0.33 mm (Y = 0.30 mm, n = 5). Urogomphus. Total length of urogomphus = 1.78- 1.95 mm (Y = 1.84 mm, n = 5) [length of urogomphomere 1 = 1.18- 1.33 mm (Y = 1.26 mm, n = 5)]; urogomphus 2.29-2.49 times HW (length of Urol/HW = 1.54- 1.75), and 5.96-6.3 1 times LLAS (length of UrolLLAS = 4.05-4.42); Urol/Uro2 = 2.05-2.36 (Urol/U~-02'= 1.98-2.60). Description, Third-instar Larva (Figs. 36,37,56,57). As second-instar larva except for the following characters: Colour. Head appendages, maxillary palpomere 2 either piceous or creamy white apically; thorax, terga more predominantly yellowish with a few greyish black maculae; legs, lightly infuscate distally over segments; abdomen, terga predominantly greyish black with two median yellowish maculae; urogomphus, urogomphomere 1 more shortly infus- cate apically. Head(Figs. 36,37). HL= 1.07-1.21 mm(Y= 1.13 mm, n=5); HW=0.95-1.13 mm (Y = 1.05 mm, n = 5); FCL = 0.82-0.93 mm (T = 0.87 mm, n = 5); cephalic capsule FCLRCW = 2.19-2.48; lateral margin of parietale with temporal spines; antenna, A3'/A4 = 0.34-0.43. Legs (Figs. 56, 57). Position and number of secondary setae as expressed in Table 4; posterior metatarsal claw 0.45-0.70 times length of metatarsus. Abdomen. MBWLASW = 2.39; LLAS = 0.46-0.52 mm (F = 0.49 mm, n = 5). Urogomphus. Total length of urogomphus = 2.50-2.81 mm (Y = 2.64 mm, n = 5); [length of urogomphomere 1 = 1.72-2.02 mm (T= 1.84 mm, n = 5)]; urogomphus 2.35-2.86 times HW (length of urogomphomere 1/HW = 1.63-1.93), and 4.92-5.95 times LLAS (length of UrolLLAS = 3.48-4.02); Urol/Uro2 = 2.08-2.59 (UrolKJro2' = 2.18-2.76). Source of Reared or Associated Material. Eggs were obtained from adults collected at the following localities: CANADA. Alberta. Elbow River at Twin Bridges, 4 km W Calgary on Hwy 8, 16.VI.1991;British Columbia. Fernie, Elk River, 29.V.1992; Yukon Territory. Klondike River, Jct of Dempster Hwy and Alaskan Hwy, 25 & 27.VI.1994; Dempster Hwy 100 km N Alaskan Hwy, 26.VI.1994. Additional larval specimens were obtained in association with adults at the following locality: USA. Washington. Thurston Co., Creek at Hwy 7 in Elbe, 30.V. 1995. Taxonomic Notes. Oreodytes laevis has a very extensive distribution within North America which overlaps in some parts with the ranges of 0.recticollis, 0.alaskanus, and 0.produc- 422 THE CANAVIAN ENIDMOLOGIST MayIJune 1997 totruncatus. The larvae of these four species are similar but the first-instar larva of 0.laevis may be distinguished from the others by its smaller size. The second- and third-instar larvae of 0.laevis are more likely to be confused with those of 0.recticollis as both species share the presence of secondary setae on the tarsi (secondary setae are lacking in 0.productotrun- catus and 0.alsakanus) (Tables 2 and 4). However, 0.laevis is distinguished from the latter by the presence of secondary setae on the dorsal margin of the tarsi. Secondary setae were found to be restricted to the ventral margin in 0.recticollis. It has been suggested that 0. laevis might be conspecific with the Palearctic species 0.alpinus (Paykull) (Zimmerman 1985; Nilsson 1987b). I had the opportunity to examine some larvae of 0.alpinus which appear fairly similar to 0. laevis. Comparison of selected measurements and ratios (Table 9) and leg chaetotaxy suggest that these species might be identical. Distribution. Oreodytes laevis has been recorded from Newfoundland to Alaska and south along the Rocky Mountains to Colorado.

Oreodytes snoqualmie (Hatch) (Figs. 23,40,73,80) Diagnostic Combination. Lateral elongation of antennomere 3 shorter, A3'1A4 generally less than 0.40; basal articulation of primary seta AN2 inserted more medially on anten- nomere 3, below anteroventral spinula (first-instar larva); coxae, in second-instar larva, with anterior secondary setae absent; primary seta TI4 elongate, more than 2.00 times longer than maximum width of metatibia in first-instar larva; pro- and mesotarsi of second- and third-instar larvae with secondary setae both on dorsal and ventral margins; smaller species. Description, First-instar Larva (Figs. 23,73). Colour. Cephalic capsule, dorsal surface predominantly greyish black except apex of frontoclypeus and around ocularium creamy white to pale yellow (Fig. 23); head append- ages, predominantly greyish black except proximal portion of antennomeres 1-3, creamy white to pale yellow; thorax, terga greyish black; legs greyish black, coxae lightly paler proximally; abdomen, terga greyish black; urogomphus, greyish black. Head (Fig. 23). HL = 0.59-0.64 mm (T = 0.61 mm, n = 3); HW = 0.52-0.56 mm (Y = 0.54 mm, n = 3); FCL= 0.46-0.49 mm (Y = 0.47 mm, n = 3); cephalic capsule, HLJHW = 1.11-1.15, HW/OcW = 1.66-1.79; FCL/FCW = 2.26-2.38; antenna, A3'/A4 = 0.25- 0.27; antennomere 3 with seta AN2 inserted subapically, lower than spinula; labium, palpomere 2, 1.36- 1.42 times length of palpomere 1. Legs. Metathoracic legs about 3.00 times HW; posterior metathoracic claw about 0.78-0.80 times length of metatarsus; length of longest between setae FE8 and FE9lwidth of metafemur = 1.12- 1SO; length of seta TI4lwidth of metatibia = 2.00-2.16; length of seta TA2lwidth of metatarsus = 1.33- 1.63. Abdomen. MBWLASW = 3.51; LLAS = 0.17-0.19 mm (F = 0.18 mm, n = 4). Urogomphus (Fig. 73). Total length of urogomphus = 1.22- 1.36 mm (T = 1.31 mm, n = 4) [length of urogomphomere 1 = 0.79-0.88 mm (T = 0.85 rnm, n = 4)]; 2.37-2.41 times HW (length of Urol/HW = 1.54-1.56), and 7.00-7.52 times LLAS (length of UrolILLAS = 4.61-4.87); Urol/Uro2 = 1.84-1.93 (Urol/Uro2' = 2.13-2.38). Description, Second-instar Larva. As first-instar larva except for the following characters: Colour. Cephalic capsule, dorsal surface paler anteriorly; thorax, meso- and metaterga with a few yellowish maculae. Head. HL= 0.85-0.86 mm (Y = 0.86 mm, n = 2); HW = 0.76 mm (Y = 0.76 mm, n = 2); FCL = 0.64-0.67 mm (T = 0.66 mm, n = 2). Cephalic capsule, FCL/FCW = 2.38-2.46; lateral margin of parietale with five to eight temporal spines; antenna, A3'/A4 = 0.23-0.31. Volume 129 THE CANADIAN ENTOMOLOGIST 423 Legs. Position and number of secondary setae as expressed in Table 2; posterior metatarsal claw 0.64-0.67 times length of metatarsus. Abdomen. LLAS = 0.27-0.28 mm (T = 0.28 mm, n = 3). Urogomphus. Total length of urogomphus = 1.77- 1.8 1 mm (T = 1.79 mm, n = 4) [length of urogomphomere 1 = 1.20- 1.28 mm (T = 1.23 mm, n = 4)]; urogomphus 2.32-2.38 times HW (length of Urol/HW = 1.58-1.63), and 6.44-6.50 times LLAS (length of UrolLLAS = 4.38-4.46); Urol/Uro2 = 2.12-2.21 (UrolKJro2' = 2.33-2.52). Description, Third-instar Larva (Figs. 40, 80). As second-instar larva except for the following characters: Colour. Cephalic capsule, dorsal surface more predominantly creamy white to pale yellow (Fig. 40); head appendages, creamy white except antennomere 4, apex of anten- nomere 3, maxillary palpomere 3, apex of maxillary palpomere 2, and apex of labial palpomere 2 infuscate; thorax, protergum greyish black with a few creamy white maculae posteriorly, meso- and metaterga predominantly creamy white to pale yellow with a few piceous black maculae; legs predominantly creamy white, femora, tibiae, and tarsi infuscate dorsally; abdomen, terga more predominantly yellowish; urogomphus, urogomphomere 1 yellowish to pale grey proximally, darker distally. Head (Fig. 40). HL = 1.09- 1.14 mm (T = 1.10 mm, n = 4); HW = 0.97- 1.00 mm (T = 0.99 mm, n = 4); FCL= 0.85 -0.87 mm (T = 0.86 mm, n = 4); cephalic capsule (Fig. 40), FCLIFCW = 2.3 1-2.45; lateral margin of parietale with 8- 13 temporal spines; antenna, A3'/A4 = 0.26-0.32. Legs. Position and number of secondary setae as expressed in Table 4; posterior metatarsal claw 0.53-0.58 times length of metatarsus. Abdomen. MBWLASW = 3.00; LLAS = 0.40-0.44 mm (T = 0.41 rnrn, n = 3). Urogomphus (Fig. 80). Total length of urogomphus = 2.49-2.58 mm (T = 2.51 mm, n = 4) [length of urogomphomere 1 = 1.72- 1.76 mm (T = 1.74 mm, n = 4)]; urogomphus 2.49-2.67 times HW (length of urogomphomere 1/HW= 1.72-1.81), and 6.08-6.28 times LLAS (length of UrolLLAS = 3.95-4.44); Urol/Uro2 = 2.09-2.42 (Urol/Uro2'= 2.20-2.54).

Source of Reared or Associated Material. Eggs were obtained from adults collected at the following localities: CANADA. Alberta. Elbow River at Beaver Flat, 25 km W Bragg Ck, 16.VI.1991; Lundbreck Falls, near Lundbreck, 28.V. 1992. Taxonomic Notes. First-instar larvae differ from other members of the 0. scitulus species- group by the presence of a very elongate primary seta TI4 on the metatibia. As second- and third-instar larvae, 0. snoqualmie may be confused with either 0. laevis or 0.recticollis because all three species share the presence of secondary setae on the tarsi. However, 0.snoqualmie differs from 0.recticollis by the presence of secondary setae on the dorsal margin of the tarsi (Tables 2 and 4), a smaller size (cephalic capsule), and its range of distribution, and from 0.laevis by a more elongate urogomphomere 1. Distribution. Oreodytes snoqualmie is known from western Alberta, southern British Columbia, Washington, and Wyoming.

Oreodytes recticollis (Fall) (Figs. 18,26,41) Diagnostic Combination. Lateral elongation of antennomere 3 shorter, A3'/A4 generally less than 0.40; basal articulation of primary seta AN2 inserted more apically on anten- nomere 3, at about level of the anteroventral spinula (first-instar larva) (Fig. 18); coxae, in second-instar larva, with anterior secondary setae present; primary seta TI4 short, less than 1.90 times longer than maximum width of metatibia in fnst-instar larva; pro- and mesotarsi 424 THE CAPCADIAN ENTOMOLOGIST MayJJune 1997 of second- and third-instar larvae with secondary setae restricted to ventral margin; larger species. Description, First-instar Larva (Figs. 18,26). Colour. Cephalic capsule, dorsal surface predominantly greyish black, except anterior portion of frontoclypeus and around ocularium, creamy white to pale yellow; head appendages, creamy white except antennomere 4, apex of antennomere 3, maxillary palpomere 3, apex of maxillary palpomere 2, and apex of labial palpomere 2 infuscate; thorax, terga greyish black anteriorly, creamy white to pale yellow posteriorly; legs, piceous dorsally, creamy white to pale yellow ventrally; abdomen, terga pale grey; urogomphus, predominantly greyish black. Head (Figs. 18,26). HL = 0.64-0.69 mm (2 = 0.66 rnm, n = 5); HW = 0.59-0.63 mm (Y = 0.61 mm, n = 5); FCL= 0.50-0.54 mm (Y = 0.52 mm, n = 5); cephalic capsule (Fig. 26), HLIHW = 1.05-1.13, HWIOcW = 1.51-1.63; FCLFCW = 2.22-2.33; antenna (Fig. IS), A3'1A4 = 0.25-0.29; antennomere 3 with seta AN2 inserted subapically, at about level of spinula; labium, palpomere 2, 1.16- 1.23 times length of palpomere 1. Legs. Metathoracic legs about 2.80 times HW, posterior metathoracic claw about 0.73-0.77 times length of metatarsus; length of longest between setae FE8 and FE91width of metafemur = 0.89-0.95; length of seta TI4/width of metatibia = 1.43- 1.67; length of seta TA21width of metatarsus = 1.11- 1.32. Abdomen. MBWLASW = 3.11; LLAS = 0.20-0.21 mm (Y = 0.20 mm, n = 5). Urogomphus. Total length of urogomphus = 1.31 - 1.39 mm (T = 1.36mm, n = 5) [length of urogomphomere 1 = 0.90-0.97 mm (Y = 0.93 mm, n = 5)]; 2.06-2.31 times HW (length of Urol/HW= 1.43-1.63), and6.29-7.11 times LLAS (lengthof UrolLLAS =4.33-4.95); Urol/Uro2 = 1.98-2.39 (Urol/Uro2' = 2.45-2.86). Description, Second-instar Larva. No specimen of the second-instar larva was available for description. Description, Third-instar Larva (Fig. 41). As first-instar larva except for the following characters: Colour. Cephalic capsule, dorsal surface predominantly creamy white except for V-shaped pattern posteriorly along coronal suture, and occipital region blackish; thorax, terga predominantly yellowish with several blackish maculae; legs, creamy white except for some greyish maculae over distal segments; abdomen, terga predominantly pale grey with some yellowish maculae, terga 3 and 4 paler. Head(Fig.41).HL=1.27mm(Y=1.27mm,n=2);HW=1.18-1.22mm(Y=1.20mm, n = 2); FCL = 0.98- 1.00 mm (Y = 0.99 mm, n = 2); cephalic capsule (Fig. 41), FCL/FCW = 2.3 1-2.38; lateral margin of parietale with 11- 14 temporal spines; antenna, A3'/A4 = 0.37-0.38. Legs. Position and number of secondary setae as expressed in Table 4; posterior metatarsal claw 0.53 times length of metatarsus. Abdomen. MBWILASW = 2.33; LLAS = 0.46-0.49 mm (7 = 0.47 mm, n = 2). Urogomphus. Total length of urogomphus = 2.63-2.73 mm (F = 2.67 mm, n = 2); [length of urogomphomere 1 = 1.7 1- 1.90 mm (2 = 1.8 1 mm, n = 2)]; urogomphus 2.23-2.28 times HW (length of urogomphomere 1/HW = 1.45- 1.56), and 5.42-5.77 times LLAS (length of UrolLLAS = 3.53-4.12); Urol/Uro2 = 1.96 (Urol/Uro2' = 2.03-2.23). Source of Reared or Associated Material. Eggs were obtained from adults collected at the following localities: CANADA. Yukon Territory. Dempster Hwy, 100 km N Alaskan Hwy, 26.VI.1994; Klondyke River, Jct of Dempster Hwy and Alaskan Hwy, 27.VI.1994. Taxonomic Notes. The first-instar larva of 0.recticollis is unique among members of the 0. scitulus species-group in that primary seta AN2 is inserted more apically on antenno- Volume 129 THE CANADIAN ENTOMOLOGIST 425 mere 3, at about the level of the ventroapical spinulae (Fig. 18). In all other species, seta AN2 is well below the spinulae. See also under 0.laevis and 0.snoqualmie.

Distribution. Oreodytes recticollis is known from southeastern Alaska and western Yukon.

Oreodytesproductotrtlncatus (Hatch) (Figs. 25,42,64)

Diagnostic Combination. Lateral elongation of antennomere 3 shorter, A3'1A4 generally less than 0.40; basal articulation of primary seta AN2 inserted more medially on anten- nomere 3, below anteroventral spinula (first-instar larva); coxae, in second-instar larva, with anterior secondary setae present; primary seta TI4 short, less than 1.90 times longer than maximum width of metatibia in first-instar larva; pro- and mesotarsi of second- and third-instar larvae lacking secondary setae; larger species.

Description, First-instar Larva (Figs. 25,64). Colour. Cephalic capsule, dorsal surface predominantly greyish black except anterior portion of frontoclypeus and around ocularium creamy white to pale yellow (Fig. 25); head appendages greyish except basal portion of antennomere 2 and 3 pale yellow; thorax, terga pale grey, protergum lightly paler posteriorly; legs, piceous dorsally, creamy white to pale yellow ventrally; abdomen, terga pale grey; urogomphus, predominantly greyish black, urogomphomere 1 paler proximally. Head (Fig. 25). HL = 0.65-0.66 mm (T = 0.66 mm, n = 2); HW = 0.58-0.60 mm (T = 0.59 mm, n = 2); FCL= 0.50-0.5 1 mm (Y = 0.50 mm, n = 2); cephalic capsule (Fig. 25), HLIHW = 1.10-1.12, HWIOcW = 1.51-1.58; FCL/FCW = 2.24; antenna, A3'1A4 = 0.24- 0.25; antennomere 3 with seta AN2 inserted subapically, lower than spinula; labium, palpomere 2, 1.30- 1.41 times length of palpomere 1. Legs. Metathoracic legs about 3.00 times HW; posterior metathoracic claw about 0.79-0.88 times length of metatarsus; length of longest between setae FE8 and FiE9/width of metafemur = 0.97-1.05; length of seta TI41width of metatibia = 1.86; length of seta TA2lwidth of metatarsus = 1.27- 1.35. Abdomen (Fig. 64). MBWLASW=2.89; LLAS =0.19-0.20mm(Y=0.19mm, n = 2). Urogomphus. Total length of urogomphus = 1.39- 1.43 mm (T = 1.41 mm, n = 2) [length of urogomphomere 1 = 0.90-0.94 mm (Y = 0.92 mm, n = 2)]; 2.37 times HW (length of Urol/HW= 1.53- 1.56), and7.13-7.45 times LLAS (lengthof UrolLLAS =4.68-4.82); UrolKJro2 = 1.83-1.92 (Urol/Uro2'= 2.29-2.31).

Description, Second-instar Larva. As first-instar larva except for the following characters: Colour. Cephalic capsule paler anteriorly; head appendages, creamy white to pale yellow, except antennomere 4, apex of antennomeres 2 and 3, apex of maxillary palpomere 2 and 3, and apex of labial palpomere 2 infuscate; thorax, terga more predominantly yellowish with several blackish maculae; abdomen, tergum 7 yellowish to pale grey. Head. HL = 0.97 mm (T = 0.97 mm, n = 2); HW = 0.90 mm (T = 0.90 mm, n = 2); FCL = 0.73-0.74 mm (Y = 0.74 mm, n = 2); cephalic capsule, FCL/FCW = 2.17-2.27; lateral margin of parietale with six to eight temporal spines; antenna, A3'1A4 = 0.26-0.30. Legs. Position and number of secondary setae as expressed in Table 2; posterior metatarsal claw 0.66-0.71 times length of metatarsus. Abdomen. LLAS = 0.32-0.33 mm (T = 0.33 mm, n = 2). Urogomphus. Total length of urogomphus = 2.04 mm (Y = 2.04 mm, n = 2) [length of urogomphomere 1 = 1.33-1.35 mm (T = 1.34 mm, n = 2)]; urogomphus 2.26-2.30 times HW (length of UrolJHW = 1.47-1.48), and 6.12-6.32 times LLAS (length of UrolLLAS = 3.99-4.19); Urol/Uro2 = 1.81-1.86 (Urol/Uro2' = 1.92-2.03). 426 THE CANADIAN Eh'TOMOLOGIST MayIJune 1997 Description, Third-instar Larva (Fig. 42). As second-instar larva except for the following characters: Colour. Cephalic capsule, frontoclypeus predominantly creamy white with medial pale grey macula posteriorly, parietale with black V-shaped macula along the coronal suture (Fig. 42); legs, more predominantly creamy white over proximal segments. Head (Fig. 42). HL = 1.23-1.35 mm (Z = 1.30 mm, n = 4); HW = 1.18-1.25 mm (Y = 1.22 mm, n =4); FCL= 0.96- 1.03 mm (T = 1.01 mm, n=4); cephalic capsule (Fig. 42), FCLPCW = 2.08-2.3 1; lateral margin of parietale with 9- 12 temporal spines; antenna, A3'/A4 = 0.32-0.34. Legs. Position and number of secondary setae as expressed in Table 4; posterior metatarsal claw 0.57-0.59 times length of metatarsus. Abdomen. MBWLASW = 2.99; LLAS = 0.50-0.52 mm (E = 0.50 mm, n = 4). Urogomphus. Total length of urogomphus = 2.62-2.91 mm (Z= 2.8 1 mm, n = 4) [length of urogomphomere 1 = 1.75- 1.91 mm (7 = 1.85 mm, n = 4)]; urogomphus 2.23-2.34 times HW (length of urogomphomere 1/HW = 1.48-1.57), and 5.10-5.88 times LLAS (length of UrolLLAS = 3.40-3.86); Urol/Uro2 = 1.72-2.08 (Urol/Uro2'= 1.77-2.15). Source of Reared or Associated Material. Eggs were obtained from adults collected at the following locality: CANADA. Alberta. Bragg Ck at Beaver Flat, 03.VI.1992. Taxonomic Notes. Larvae of 0.productotruncatus are similar to those of 0. alaskanus. Even though urogomphomere 1 is shorter in 0.productotruncatus, distribution is the easiest way to identify the larvae. Distribution. Oreodytes productotruncatus occurs in the Rocky Mountains of western Alberta, southeastern British Columbia, and western Montana.

Oreodytes alaskanus (Fall) (Fig. 43) Diagnostic Combination. Lateral elongation of antennomere 3 shorter, A3'/A4 generally less than 0.40; basal articulation of the primary seta AN2 inserted more medially on antennomere 3, below anteroventral spinula (observed in second- and third-instar larva only); coxae, in second-instarlarva, with anterior secondary setae present; pro- and mesotarsi of second- and third-instar larvae lacking secondary setae; larger species. Description, First-instar Larva. No specimen of the first-instar larva was available for description. Description, Second-instar Larva. Colour. Cephalic capsule, predominantly greyish black, frontoclypeus creamy white anteriorly, parietale creamy around ocularium; head appendages, predominantly greyish black, generally paler proximally over every article; thorax, terga predominantly greyish black; legs, greyish dorsally, yellowish ventrally; abdomen, terga pale grey; urogomphus, pale grey. Head. HL= 0.90-0.97 mm (E = 0.93 mm, n = 5); HW = 0.85-0.89 mm (Z = 0.87 mm, n = 5); FCL= 0.68-0.76 mm (T = 0.72 mm, n = 5); cephalic capsule, FCLPCW = 2.14-2.38; lateral margin of parietale with four to five temporal spines; antenna, A3'/A4 = 0.23-0.29. Legs. Position and number of secondary setae as expressed in Table 2; posterior metatarsal claw 0.60-0.65 times length of metatarsus. Abdomen. LLAS = 0.31-0.34 mm (Z = 0.33 mm, n = 5). Urogomphus. Total length of urogomphus = 1.87-2.20 mm (T = 1.97 mm, n = 5) [length of urogomphomere 1 = 1.29- 1.52 mm (Z = 1.41 mm, n = S)]; urogomphus 2.20-2.50 times HW (length of Urol/HW = 1.51 - 1.72), and 5.96-6.8 1 times LLAS (length of UrolLLAS = 4.10-4.69); Urol/Uro2 = 1.98-2.20 (Urol/Uro2' = 2.17-2.55). Volume 129 THE CANADIAN iTVOMOLOGIST 427 Description, Third-instar Larva (Fig. 43). As second-instar larva except for the following characters: Colour. Cephalic capsule, dorsal surface either predominantly creamy white, with black V-shaped macula along coronal suture or more broadly darkened posteriorly, with basal half of frontoclypeus greyish black; head appendages creamy white except antennomere 4, apex of antennomere 3, maxillary palpomere 3, apex of maxillary palpomere 2, and apex of labial palpomere 2 infuscate; thorax, terga predominantly yellowish with several blackish maculae; legs predominantly greyish, coxae and trochanter more broadly creamy white; abdomen, terga pale grey with some whitish maculae, tergum 7 predominantly creamy white to pale yellow; urogomphus, yellow to pale grey. Head (Fig. 43). HL = 1.29-1.34 mm (T = 1.31 mm, n = 5); HW = 1.18-1.30 mm (T = 1.24 mm, n = 5); FCL = 1.00- 1.02 mm (T = 1.O1 mm, n = 5); cephalic capsule (Fig. 43), FCL/FCW = 2.19-2.29; lateral margin of parietale with 9-14 temporal spines; antenna, A3'/A4 = 0.30-0.36. Legs. Position and number of secondary setae as expressed in Table 4; posterior metatarsal claw 0.54-0.58 times length of metatarsus. Abdomen. MBW/LASW = 2.88; LLAS = 0.52-0.53 mm (Y = 0.52 mm, n = 5). Urogomphus. Total length of urogomphus = 2.43-2.90 mm (T = 2.67 mm, n = 5) [length of urogomphomere 1 = 1.72- 1.99 mm (F = 1.89 mm, n = 5)]; urogomphus 2.12-2.3 1 times HW (length of urogomphomere 1/HW = 1.46- 1.61), and 5.17 -5.53 times LLAS (length of Urol/LLAS = 3.35-3.86); Urol/Uro2 = 1.99-2.81 (Urol/Uro2' = 2.10-2.96). Source of Reared or Associated Material. Larvae were obtained in association with adults collected at the following locality: USA. Washington. Pierce Co., Carbon River at Hwy 162, 14 km W Buckley, 29-30.V.1995. Eggs were also obtained from adults collected at the following locality: USA. Alaska. Skagway, Skagway River, 28.VI.1994 (no hatchling obtained). Taxonomic Notes. See under 0.productotruncatus. Distribution. Oreodytes alaskanus is distributed along coastal Alaska, British Columbia, and Washington.

THEOREODYTES OBESUS SPECIES-GROUP (Figs. 10-15,27-33,45-51,60,61,67,68,71,74,81) This species-group comprises fairly similar species formerly included in the angustior species-group of Zimmerman (1985) which also incorporated both 0. picturatus and 0.angustior. Diagnostic Combination. Body broader, MBWILASW > 4.20; lamellae clypeales gener- ally not interrupted medially for short distance; antennomere 3 with pore ANf absent (Figs. 12- 15); primary seta AN2 inserted subapically, lower or at about level of the ventral spinula (Figs. 12- 15); temporal spines not numerous, more seta-like (Figs. 45-5 1); spinulae lacking on ventral margin of tibiae and tarsi (Figs. 60,61); abdomen segments 7 and 8 lacking bluntly rounded secondary setae; primary seta AB5 elongate, extending well beyond apex of siphon (Figs. 67, 68); urogomphus short, less than 1.60 times HW (urogomphomere 1 less than 0.80 times longer than HW) (Figs. 74, 81); urogomphomere 1 at most 1.40 times longer than urogomphomere 2, lacking bluntly rounded secondary setae (Fig. 8 1); primary setae UR2, UR3, and UR4 close together, variably inserted, contiguously articulated or about subequally distant, setae UR2 and UR3 inserted ventrally and dorsolaterally respectively (Fig. 74); primary seta UR8 inserted subapically on urogomphomere 2 [Uro2'/Uro2 > 0.70, in first-instar larva (Fig. 74)]. Description, First-instar Larva (Figs. 10- 15,27-33,67,68,74). 428 THE CAN ADLAN E?47OMOLOGIm MayIJune 1997 Colour. Cephalic capsule, dorsal surface predominantly greyish black or predomi- nantly creamy white with a blackish pattern posteriorly over parietale, basal portion of frontoclypeus, and occipital region; head appendages, greyish black or creamy white to pale yellow with distal articles infuscate apically; thorax, protergum pale grey, meso- and metaterga creamy white or pale grey; legs, predominantly creamy white or predominantly greyish black; abdomen, terga pale grey to black; urogomphus, urogomphomere 1 greyish black or predominantly creamy white, urogomphomere 2 greyish black. Head (Figs. 10-15, 27-33). HL = 0.42-0.59 mm; HW = 0.40-0.58 mm; FCL = 0.31-0.45 mm; cephalic capsule (Figs. 27-33) about as long as broad (HL/HW = 0.98- 1.04), with a neck constriction slightly to distinctly delimited (HWIOcW = 1.39- 2.02); FCLIFCW = 1.53-2.66; frontoclypeus with side at most slightly sinuate at level of lateral notches; lamellae clypeales generally not interrupted medially for short distance; antenna (Figs. 12-15), length of antenna/HW = 0.56-0.67; A2/A3 = 0.64- 0.83; A3'1A4 = 0.33-0.42; antennomere 3 with pore ANf lacking, and seta AN2 inserted subapically, lower or at about same level of spinula; maxilla, length of antenna/length of maxillary palpus = 1.11- 1.22; setae MX2, MX3, and MX4 either short (Figs. 7,8) or elongate (Figs. 10, 11); maxillary stipes with additional seta present (Figs. 10, 11) or absent (Figs. 7, 8); labium, length of maxillary palpus/length of labial palpus = 1.19- 1.33; palpomere 2, 1.51-2.17 times length of palpomere I. Legs. Metathoracic legs about 1.20 times length of prothoracic legs, and 2.18-2.55 times HW; posterior metathoracic claw about 0.63-0.75 times length of metatarsus; spinulae lacking on ventral margin of tibiae and tarsi; length of longest between setae FE8 and FE9lwidth of metafemur = 0.79- 1.24; length of seta TI4lwidth of metatibia = 0.77- 1.56; length of seta TA2lwidth of metatarsus = 0.52-0.99. Abdomen (Figs. 67, 68). MBW/LASW = 4.20-4.60; LLAS = 0.12-0.18 mm; LLASIHW = 0.28-0.33; siphon variably shaped, either rounded or acute apically, about 0.26-0.38 times LLAS; primary seta AB5 elongate, extending well beyond apex of siphon (Figs. 67,68); length of seta ABll/LLAS = 0.54-0.62. Urogomphus (Fig. 74). Total length of urogomphus = 0.62-0.82 mm (length of urogomphomere 1 = 0.28-0.44 mm); 1.36- 1.59 times HW (length of Urol/HW = 0.64- 0.79), and 4.37-5.70 times LLAS (length of Urol/LLAS = 2.18-2.80); UrolKJro2 = 0.8 1- 1.24 (Uro lJUro2' = 1.21- 1.63); urogomphomere 1 lacking an additional pore; pri- mary setae UR2 and UR3 inserted ventrally and dorsolaterally respectively; basal articula- tions of primary setae UR2, UR3, and UR4 contiguous; basal articulation of seta UR8 inserted apically on urogomphomere 2 (Uro2'/Uro2 = 0.70-0.77). Description, Second-instar Larva. As first-instar larva except for the following characters: Colour. Thorax, pro- and mesoterga greyish black, metatergum creamy white to pale yellow or pale grey; abdomen, terga 1, 2,6, 7, and 8 predominantly creamy white to pale yellow or predominantly greyish black; urogomphus, urogomphomere 2 grey to black. Head. HL = 0.55-0.77 mm; HW = 0.58-0.73 mm; FCL = 0.43-0.59 mm; HL/HW = 1.05- 1.12; cephalic capsule, FCLIFCW = 1.76-2.95; lateral margin of parietale with zero to five temporal spines, not bluntly rounded, and more seta-like in appearance (Figs. 45 -5 1); antenna, length of antenna/HW = 0.54-0.61; A2lA3 = 0.83-0.87; A3'/A4 = 0.34-0.40; maxilla, length of antenna~lengthof maxillary palpus = 1.07- 1.21, palpomere 2,030- 1.33 times length of palpomere 1; labium, palpomere 2, 1.10- 1.65 times length of palpomere 1. Legs. Metathoracic legs 1.20-1.30 times length of prothoracic legs; position and number of secondary setae as expressed in Table 3; posterior metatarsal claw 0.54-0.63 times length of metatarsus. Abdomen. LLAS = 0.17-0.25 mm; siphon, 0.14-0.34 times LLAS; abdomen seg- ments 7 and 8 lacking bluntly rounded secondary setae. Volume 129 THE CANADIAN ENTOMOLOGIST 429

Urogomphus. Total length of urogomphus = 0.80-1.06 mm (length of urogom- phomere 1 = 0.34-0.49 mm); urogomphus 1.25-1.64 times HW (length of UrolIHW = 0.53-0.75), and 4.32-5.07 times LLAS (length of UrolLLAS = 1.91-2.31); urogom- phomere 1 lacking bluntly rounded secondary setae; Urol/Uro2 = 0.72-0.93 (Urol/Uro2' = 0.79- 1.02). Description, Third-instar Larva (Figs. 45-51, 60, 61, 71, 81). As second-instar larva except for the following characters: Colour. Thorax, protergum creamy white to pale yellow or greyish black, terga generally with lateral creamy white stripe on each side; abdomen, terga 1, 2, 6, 7, and 8 predominantly creamy white to pale yellow or predominantly greyish black, terga 1-6 generally with lateral creamy white stripe on each side; urogomphus, urogomphomere 2 grey to black. Head. HL = 0.70-0.97 mm; HW = 0.67-0.95 rnm; FCL = 0.52-0.74 rnm; cephalic capsule (Figs. 45-5 I), FCL/FCW = 1.79-3.19; lateral margin of parietale with one to eight temporal spines; antenna, A2/A3 = 0.86- 1.03; A3'1A4 = 0.39-0.54; maxilla, length of antennallength of maxillary palpus = 1.03- 1.13, palpomere 2,0.73- 1.02 times length of palpomere 1; labium, length of maxillary palpus/length of labial palpus = 1.22- 1.45; palpomere 2, 0.90- 1.22 times as long as palpomere 1. Legs (Figs. 60, 61). Position and number of secondary setae as expressed in Table 5; posterior metatarsal claw 0.48-0.75 times length of metatarsus. Abdomen (Fig. 71). MBWLASW = 4.25-5.00; LLAS = 0.23-0.31 mm; LLASIHW = 0.32-0.40; siphon, 0.07-0.22 times LLAS. Urogomphus (Fig. 81). Total length of urogomphus = 0.85-1.25 mm (length of urogomphomere 1 = 0.34-0.55 mm); urogomphus 1.20- 1.55 times HW (length of urogom- phomere 1/HW = 0.50-0.65), and 3.51-4.09 times LLAS (length of UrolLLAS = 1.48- 1.78); UrolIUro2 = 0.62-0.86 (Urol/Uro2' = 0.68-0.92). Source of Reared or Associated Material. Within the genus Oreodytes, larvae of members of the 0.obesus species-group are very easy to recognize because of their broad fusiformate body shape and small size. Head appendages and legs of these species are also slightly shorter than for other species of the genus. The larvae of the 0.obesus species-group are also characterized by several more subtle features which require use of a compound microscope for observation (see under Character Analysis). If we except 0.subrotundus which shows several unique features, the species included in the 0. obesus species-group are all fairly similar morphologically. Based on colour patterns, those species may be subdivided into two species-group: larvae of 0.sierrae, 0.subrotundus, 0.crassulus, and 0.abbreviatus are almost completely dark grey to black; in comparison, those of 0.obesus, 0.sanmarkii, and 0.congruus are characterized by an alternating black and white pattern over the body.

KEY TO THE KNOWN SPECIES OF THE OREODYTES OBESUS SPECIES-GROUP

Key to First-instar Larvae

1. Frontoclypeus narrower, FCL/FCW > 2.50 (Fig. 28); primary setae MX2, MX3, and MX4 elongate (Fig. 10); maxillary stipes with one elongate additional seta on dorsal surface (Fig. 10); primary seta AN3 inserted lower than ventroapical spinula on antennomere 3 (Fig. 14) ...... 0.subrotundus - Frontoclypeus broader, FCL/FCW < 2.20 (Figs. 27-33); primary setae MX2, MX3, and MX4 minute-like (Fig. 6); maxillary stipes lacking additional seta (Fig. 6); primary seta AN3 inserted at about level or higher than ventroapical spinula on antennomere 3 (Figs. 12, 13, 15) ...... 2 430 THE CAN.4DlM-J EhTOMOLOFIST MayJJune 1997 Frontoclypeus narrower, FCL/FCW > 2.10 (Fig. 27); ratio HW/OcW > 1.80; siphon narrow, generally with a distinct notch on lateral margin at about midlength (Fig. 68); larger species, HL >0.57mm ...... 0.sierrae Frontoclypeus broader, FCL/FCW < 2.00 (Figs. 29-33); ratio HW/OcW < 1.80; siphon narrow or broad, lacking a notch on lateral margin at about midlength (Fig. 67); smaller species, HL<0.49mm ...... 3

Primary seta TI4 short, less than 0.96 times longer than maximum width of metatibia; siphon very narrow and acute apically (Fig. 67); body predominantly dark grey to black ..... 0.crassulus Primary seta TI4 longer, more than 1.09 times longer than maximum width of metatibia; siphon broader, and bluntly rounded apically; body more predominantly creamy white ...... 4

Frontoclypeus broader, FCL/FCW < 1.80 (Figs. 29,30)...... 0. obesus Frontoclypeus narower, FCLIFCW > 1.90 (Figs. 31,32) ...... 5

Western low arctic ...... 0.sanmarkii Western Alberta and central British Columbia south to New Mexico and California ...... 0.congruus Key to Second- and Third-instar Larvae

Frontoclypeus narrower, FCL/FCW > 2.90 (Fig. 49); primary setae MX2, MX3, and MX4 elongate (Fig. 10); maxillary stipes with one elongate additional seta on dorsal surface (Fig. 10); meso- and metatibiae with six and 11 secondary setae respectively...... 0.subrotundus Frontoclypeus broader, FCL/FCW < 2.50 (Figs. 45-48,50,51); primary setae MX2, MX3, and MX4 minute-like (Fig. 6); maxillary stipes lacking additional seta (Fig. 6); meso- and metatibiae with less than four and seven secondary setae respectively (Figs. 60,61)...... 2

Mesothorax and abdominal segments 1-7 lacking spiracular openings (second-instar larva) ... 3 Mesothorax and abdominal segments 1-7 with spiracular openings present (third-instar larva) ...... 6

Frontoclypeusnarrower, FCL/FCW > 2.40; labial palpomere 2 more than 1.50 times longer than labial palpomere 1; larger species, HL > 0.74 mm...... 0.sierrae Frontoclypeus broader, FCL/FCW < 2.20; labial palpomere 2 less than 1.40 times longer than labial palpomere I; smaller species, HL < 0.70 mm ...... 4

Frontoclypeus broader, FCL/FCW <1.80; smaller species, HL < 0.57 mm...... 0.obesus Frontoclypeus narrower, FCL/FCW > 2.10; larger species, HL > 0.64 mm ...... 5

Urogomphomere 1 about 0.70 times longer than HW; body more predominantly creamy white; western low arctic ...... 0.sanrnarkii Urogomphomere I about 0.50 times longer than HW, body predominantly dark grey to black; Washington to California...... 0. abbreviatus

Frontoclypeus narrower, FCL/FCW > 2.30 (Fig. 48); larger species, HL > 0.89 mm . 0.sierrae Frontoclypeus broader, FCL/FCW < 2.20 (Figs. 45-47,50,51); smaller species, HL < 0.84 mm ...... 7

Larger species, HL > 0.82 mm ...... 8 Smaller species, HL < 0.77 mm ...... 9

Pro-, meso- and metacoxae with less than three, nine, and seven secondary setae respectively; profemur with less than 14 secondary setae; body predominantly creamy white; western low arctic ...... 0.sanmarkii' Volume 129 THE CANADIAN ENMMOLOGIST 43 1 - Pro-, meso- and metacoxae with more than seven, 13, and 10 secondary setae respectively; profemur with more than 19 secondary setae; body predominantly dark grey to black; Washington to California...... 0.abbreviatus

9. Frontoclypeus narrower, FCL/FCW > 2.05 (Fig. 46) ...... 0.crassulus - Frontoclypeus broader, FCL/FCW < 1.95 (Figs. 50,51)...... 0. congruus and 0. obesus

Oreodytes sierrae Zimmerman (Figs. 13,28,48,60,61,68,74,81)

Diagnostic Combination. Frontoclypeus narrow (Figs. 27,48), with longer secondary setae dorsoapically (Fig. 48); primary seta AN2 inserted at about level of ventroapical spinula on antennomere 3 in first-instar larva (Fig. 13); primary setae MX2, MX3, and MX4 minute; maxillary stipes lacking additional seta on dorsal surface; siphon narrow, acute apically, generally with a distinct notch on lateral margin at about midlength in first-instar larva (Fig. 68); dark and large species. Description, First-instar Larva (Figs. 13,28,68,74). Colour. Cephalic capsule, dorsal surface predominantly greyish black, except apex of frontoclypeus and parietale, around ocularium, creamy white (Fig. 28); head appendages greyish black; thorax, terga pale grey, protergum slightly darker; legs, greyish black, except distal portion of coxa and trochanter creamy white; abdomen, terga pale grey, terga 6, 7, and 8 distinctly darker than rest of abdomen, siphon black; urogomphus, black. Head (Figs. 13,28). HL = 0.57-0.59 mm (2 = 0.58 mm, n = 5); HW = 0.55-0.58 mm (Y = 0.57 mm, n = 5); FCL= 0.42-0.45 mm (Z = 0.44 mm, n = 5); cephalic capsule (Fig. 28), HWIOcW = 1.80-2.06; FCLJFCW = 2.13-2.22; antenna (Fig. 13), A21A3 = 0.68-0.80; antennomere 3 with seta AN2 inserted at about same level of spinula; maxilla, setae MX2, MX3, and MX4 short; maxillary stipes lacking additional seta; labium, palpomere 2, 1.85-2.17 times length of palpomere 1. Legs. Metathoracic legs about 2.30 times HW; length of seta TI4lwidth of metati- bia = 1.14-1.30; length of seta TA2lwidth of metatarsus = 0.65-0.78. Abdomen (Fig. 68). LLAS = 0.17-0.18 mm (Y = 0.17 mm, n = 5); siphon narrow and acute apically, generally broadly sinuate at about midlength. Urogomphus (Fig. 74). Total length of urogomphus = 0.72-0.79 mm (T = 0.77 mm, n = 4) [length of urogomphomere 1 = 0.36-0.40 mm (Z = 0.38 mm, n = 4)]; 4.37-4.65 times LLAS (length of UrolLLAS = 2.18-2.34); Urol/Uro2 = 0.96- 1.01 (Urol1Uro2' = 1.29- 1.58). Description, Second-instar Larva. As first-instar larva except for the following characters: Colour. Sclerites of body darker. Head. HL = 0.74-0.77 mm (Z = 0.76 mm, n = 3); HW = 0.69-0.73 mm (Y = 0.71 mm, n = 2); FCL = 0.57-0.59 mm (Y = 0.58 mm, n = 2); cephalic capsule, FCLIFCW = 2.38-2.49; lateral margin of parietale with three to five temporal spines; maxilla, palpomere 2, 1.16- 1.33 times length of palpomere 1; labium, palpomere 2,1.50- 1.65 times length of palpomere 1. Legs. Position and number of secondary setae as expressed in Table 3. Abdomen. LLAS = 0.21-0.22 mm (Z = 0.22 mm, n = 4); siphon, 0.14-0.20 times LLAS. Urogomphus. Total length of urogomphus = 0.96-0.97 mm (T = 0.97 mm, n = 4) [length of urogomphomere 1 = 0.42-0.43 mm (Y = 0.42 mm, n = 41; urogomphus 1.36- 1.39 times HW (length of Urol/HW = 0.57-0.59), and 4.34-0.4.58 times LLAS (length of Urol/LLAS = 1.91-2.04); Urol/Uro2 = 0.76-0.80 (Urol/Uro2' = 0.89-0.96). 432 THE CANADIAN ENTOMOLOGIST MaylJune 1997 Description, Third-instar Larva (Figs. 48,60,61, 81). As second-instar larva except for the following characters: Colour. Head appendages paler; thorax, protergum variably coloured, either predominantly black or predominantly yellowish with black maculae, meso- and metaterga predominantly yellowish brown, anterior margin of mesotergum black on some specimens, terga with lateral creamy white stripe; abdomen, tergum 7 yellowish brown, terga 1- 6 with a lateral creamy white stripe. Head (Fig. 48). HL = 0.89-0.97 mm (Y = 0.93 mm, n = 4); HW = 0.88-0.95 mm (F = 0.91 mm, n = 4); FCL = 0.71-0.74 mm (F = 0.73 mm, n = 4); cephalic capsule, FCLIFCW = 2.31-2.44; lateral margin of parietale with six to eight temporal spines; maxilla, palpomere 2, 0.92-1.02 times length of palpomere 1; labium, palpomere 2, 1.12- 1.22 times as long as palpomere 1. Legs (Figs. 60, 61). Position and number of secondary setae as expressed in Table 5; posterior metatarsal claw 0.52-0.55 times length of metatarsus. Abdomen. LLAS = 0.30 mm (F = 0.30 mm, n = 4); siphon, 0.08-0.15 times LLAS. Urogomphus (Fig. 81). Total length of urogomphus = 1.05- 1.11 mm (X = 1.09 mm, n = 4) [length of urogomphomere 1 = 0.46-0.48 mm (X = 0.46 mm, n = 41; 3.51 -3.65 times LLAS (length of UroltLLAS = 1.53- 1.56); Urol/Uro2 = 0.73-0.77 (Urol/Uro2' = 0.78- 0.92). Source of Reared or Associated Material. Eggs were obtained from adults collected at the following locality: USA. California. Siskiyou Co., Jackson Ck, 12 km W Callahan on Cecilville Road, 20.V. 1994. Taxonomic Notes. The larvae of both 0.sierrae and 0. subrotundus are characterized by an overall general similarity. Compared with other members of the 0. obesus species-group, these two species may be distinguished by larger size, dark coloration, and the presence of very elongate marginal secondary setae over the thoracic and abdominal terga. The larvae of 0.sierrae differ from those of 0.subrotundus by the presence of very short primary setae MX2, MX3, and MX4 (Figs. 6, lo), the absence of additional setae on the maxillary stipes (Figs. 6, lo), the broader frontoclypeus (Figs. 27, 28,48,49), and the presence, in second- and third-instar larvae, of elongate secondary setae over the dorsal surface of the fronto- clypeus (Figs. 48,49) and a very narrow and finger-like siphon which is generally margined at about midlength with a distinct notch (Fig. 68). This siphon resembles that of 0.crassulus except that in the latter, the siphon is more acute apically and lacks a lateral notch (Fig. 67). It is noteworthy that 0.sierrae and 0.subrotundus are sympatric in part of their range (Alarie, pers. observ.) and that both have a much narrower frontoclypeus than other species of the 0. obesus species-group. Adults of both species are also similar (Zimmerman 1985). Distribution. This species has been recorded only at high elevations in the Sierra Nevada Range of northern California.

Oreodytes subrotzmdus (Fall) (Figs. 10, 11, 14,27,49)

Diagnostic Combination. Frontoclypeus narrow (Figs. 27,49), with very short secondary setae dorsoapically (Fig. 49); primary seta AN2 inserted lower than the ventroapical spinula on antennomere 3 in first-instar larva (Fig. 14); primary setae MX2, MX3, and MX4 very elongate (Fig. 10); maxillary stipes with one very elongate additional seta on dorsal surface (Fig. 10); siphon broad, bluntly rounded apically, lacking a notch on lateral margin at about midlength; dark and large species. Description, First-instar Larva (Figs. 10, 11, 14,27). Volume 129 THE CANADIAN FNWMOLOO~ST 433 Colour. Cephalic capsule, dorsal surface greyish black, except over frontoclypeus, apically, and over parietale, around ocularium, creamy white (Fig. 27); head appendages, greyish black; thorax, terga brownish grey; legs, predominantly greyish black; abdomen, terga 1-7 brownish grey, tergum 8 black; urogomphus, greyish black. Head (Figs. 10, 11, 14, 27). HL = 0.52-0.55 mm Q = 0.53 mm, n = 5); HW = 0.50-0.54 mm (Y = 0.52 mm, n = 5); FCL= 0.40-0.43 mm (Y = 0.41 mm, n = 5); cephalic capsule (Fig. 27), HW/OcW = 1.66-2.20; FCLFCW = 2.50-2.66; antenna (Fig. 14), A2/A3 = 0.71-0.83; antennomere 3 with seta AN2 inserted lower than level of spinula; maxilla (Figs. 10, 1I), setae MX2, MX3, and MX4 very elongate; maxillary stipes with one elongate additional seta; labium, palpomere 2, 1.69- 1.77 times length of palpomere 1. Legs. Metathoracic legs about 2.20 times HW, length of seta TI41width of metatibia = 1.38- 1.77; length of seta TA2/width of metatarsus = 0.87- 1.07. Abdomen. LLAS = 0.13-0.16 mm (Y = 0.17 mm, n = 5); siphon rounded to slightly acute apically. Urogomphus. Total length of urogomphus = 0.71-0.82 mm (Y = 0.76 mm, n = 6) [length of urogomphomere 1 = 0.38-0.44 mm (Y= 0.41 mm, n = 6)]; 4.61 -5.30 times LLAS (length of UrolLLAS = 2.48-2.80); Urol/Uro2 = 1.12-1.24 (UroI/Uro2'= 1.46-1.63). Description, Second-instar Larva. As first-instar larva except for the following characters: Colour. Cephalic capsule, frontoclypeus yellowish brown dorsoapically. Head. HL = 0.71 mm (n = 1); HW = 0.67 mm (n = 1); FCL = 0.56 mm (n = 1); cephalic capsule, FCL/FCW = 2.95; lateral margin of parietale with two or three temporal spines; maxilla, palpomere 2, 0.83 times length of palpomere 1; labium, palpomere 2, 1.25 times length of palpomere 1. Legs. Position and number of secondary setae as expressed in Table 3. Abdomen. LLAS = 0.21 mm (Y = 0.21 mm, n = 1); siphon, 0.14 times LLAS. Urogomphus. Total length of urogomphus = 1.01 mm (n = 1) [length of urogom- phomere 1 = 0.49 mm (n = I)]; urogomphus 1.53 times HW (length of UrolIHW = 0.72), and4.88 times LLAS (length of UrolLLAS = 2.31); Urol/Uro2 = 0.93 (Urol/Uro2'= 1.02). Description, Third-instar Larva (Fig. 49). As second-instar larva except for the following characters: Colour. Head appendages, predominantly yellowish brown; thorax, terga dark brown to dark grey, with a lateral creamy white stripe on each side; legs, predominantly yellowish over distal segment; abdomen, terga predominantly light brown, narrowly infuscate laterally and medially, and with a lateral creamy white stripe; urogomphus, yellowish brown. Head (Fig. 49). HL = 0.91 mm (n = 1); HW = 0.87 mm (n = 1); FCL= 0.73 mm (n = 1); cephalic capsule (Fig. 49), FCL/FCW = 3.19; lateral margin of parietale with two or three temporal spines; maxilla, palpomere 2, 0.71 times length of palpomere 1; labium, palpomere 2,0.91 times as long as palpomere 1. Legs. Position and number of secondary setae as expressed in Table 5; posterior metatarsal claw 0.43 times length of metatarsus. Abdomen. LLAS = 0.29 mm (n = 1); siphon, 0.07 times LLAS. Urogomphus. Total length of urogomphus = 1.11 mm (n = 1) [length of urogom- phomere 1 = 0.50 mm (n = I)]; 3.51 -3.85 times LLAS (length of UrolLLAS = 1.71); UrolIUro2 = 0.80 (Urol/Uro2' = 0.86). Source of Reared or Associated Material. Eggs were obtained from adults collected at the following localities: USA. California. Siskiyou Co., Jackson Ck, 12 km W Callahan on Cecilville Road, 11.VI.1991 and 20.V.1994; Oregon. Curry Co., Mussel Ck, Hwy 101,4 km N Ophir, 25.1V.1991 and 12.VI.1991. 434 THE CANADIAN EmMOLOOIST May/June 1997 Taxonomic Notes. The larvae of 0.subrotundus are very easy to recognize. They are dark species in colour and characterized by very elongate primary setae MX2, MX3, and MX4 (Fig. lo), the presence of an additional elongate seta on the dorsal surface of the maxillary stipes (Fig. lo), a very narrow frontoclypeus (Figs. 27,49), and the presence of very short secondary setae over the dorsoapical portion of the frontoclypeus (Fig. 49). See also under 0.sierrae. Distribution. The range of 0.subrotundus extends from northern California to Snohomish county, Washington (Zimmerman 1985).

Oreodytes abbreviatus (Fall) (Fig. 45) Diagnostic Combination (excluding the features of first-instar larva). Frontoclypeus broad (Fig. 45), with elongate secondary setae dorsoapically (Fig. 45); primary setae MX2, MX3, and MX4 minute; maxillary stipes lacking additional seta on dorsal surface; siphon broad, bluntly rounded apically; dark and small species. Description, First-instar Larva. No specimen of the first-instar larva was available for description. Description, Second-instar Larva. Colour. Cephalic capsule, dorsal surface predominantly dark brown to black, except over frontoclypeus, apically, and over parietale, around ocularium, creamy white to pale yellow; head appendages, yellowish to pale grey, infuscate apically over distal segments; thorax, pro- and mesoterga predominantly dark grey to black, metatergum predominantly creamy white to pale yellow; legs, predominantly greyish black; abdomen, terga 1,2, and 7 predominantly creamy white to pale yellow, terga 3 -5 dark grey to black, tergum 6, blackish along anterior margin, otherwise yellowish, tergum 8 yellowish along anterior margin, otherwise greyish black; urogomphus, dark yellow to pale grey. Head. HL = 0.67 mm (n = 1); HW = 0.65 mm (n = 1); FCL= 0.50 mm (n = 1); cephalic capsule, FCL/FCW = 2.11; lateral margin of parietale lacking temporal spines; maxilla, palpomere 2,1.08- 1.16 times length of palpomere 1; labium, palpomere 2,1.29- 1.33 times length of palpomere 1. Legs. Position and number of secondary setae as expressed in Table 3. Abdomen. LLAS = 0.18 mm (n = 1); siphon, 0.28 times LLAS; siphon broadly rounded apically. Urogomphus. Total length of urogomphus = 0.82 mm (n = 1) [length of urogom- phomere 1 = 0.34 mm (n = I)]; urogomphus 1.25 times HW (length of Urol/HW = 0.53), and 4.62 times LLAS (length of Urol/LLAS = 1.95); Urol/Uro2 = 0.72 (UrolKJro2' = 0.79). Description, Third-instar Larva (Fig. 45). As second-instar larva except for the following characters: Colour. Thoracic and abdominal terga with a lateral creamy white stripe. Head (Fig. 45). HL = 0.82 mm (n = 1); HW = 0.82 (n = 1); FCL = 0.62 mm (n = 1); cephalic capsule (Fig. 45), FCL/FCW = 2.12; lateral margin of parietale with two temporal spines; maxilla, palpomere 2,0.86 times length of palpomere 1; labium, palpomere 2,0.98 times as long as palpomere 1. Legs. Position and number of secondary setae as expressed in Table 5; posterior metatarsal claw 0.49 times length of metatarsus. Abdomen. LLAS = 0.27 mm (n = 1); siphon, 0.22 times LLAS. Urogomphus. Total length of urogomphus = not determined [length of urogom- phomere 1 = 0.41 mm (n = I)]; length of UrolILLAS = 1.54; Urol/Uro2 = not determined (Urol/Uro2' = 0.72). Volume 129 THE CANADIAN ENTOMOLOGIST 435 Source of Reared or Associated Material. Eggs were obtained from adults collected at the following locality: USA. California. Humboltd Co., Redwood Ck, Hwy 101 in Orick, 26-27.1V.1991 and 17.VII. 1991. Taxonomic Notes. Larvae of 0.abbreviatus, 0. sierrae, 0.subrotundus, and 0.crassulus are similar in colour with the body predominantly dark grey to black. Although only a few specimens were studied, it appears that 0.abbreviatus may be easily distinguished from the other species by size. Larvae of 0.abbreviatus are smaller than those of both 0.sierrae and 0.subrotundus, and larger than those of 0. crassulus. The shape of the frontoclypeus is another useful feature as it may help to discriminate 0.abbreviatus from both 0.sierrae and 0.subrotundus. Distribution. The range of 0.abbreviatus extends from northern California to Snohomish county in Washington (Zimmerman 1985). Oreodytes crassuhs (Fall) (Figs. 15,33,46,67) Diagnostic Combination. Frontoclypeus broad (Figs. 33,46), with elongate secondary setae dorsoapically (Fig. 46); primary seta AN2 inserted at a higher level than the ventroapical spinula on antennomere 3 of first-instar larva (Fig. 15); primary setae MX2, MX3, and MX4 minute (Fig. 6); maxillary stipes lacking additional seta on dorsal surface (Fig. 6); siphon narrow, acute apically, lacking a notch on lateral margin at about midlength (Fig. 67); dark and small species. Description, First-instar Larva (Figs. 15,33,67). Colour. Cephalic capsule, dorsal surface predominantly greyish black, paler grey apically over frontoclypeus and around egg-bursters (Fig. 33); head appendages, predominantly creamy white except antennomere 4, apex of antennomere 3, apex of maxillary palpomere 3, and apex of labial palpomere 2 infuscate; thorax, terga pale grey; legs, predominantly greyish black, except coxa and trochanter creamy white over distal portion; abdomen, terga pale grey, terga 6,7, and 8 distinctly darker than rest of abdomen; urogomphus, black. Head (Figs. 15,33). HL = 0.42-0.46 mm (Z = 0.44 mm, n = 2); HW = 0.40-0.45 mm (T = 0.42 mm, n = 2); FCL = 0.33-0.36 mm (T = 0.35 mm, n = 2); cephalic capsule (Fig. 33), HW/OcW = 1.48- 1.52; FCL/FCW = 1.93- 1.99; antenna (Fig. 15), A2/A3 = 0.64; anten- nomere 3 with seta AN2 inserted more apically than spinula; maxilla, setae MX2, MX3, and MX4 short; maxillary stipes lacking additional seta; labium, palpomere 2, 1.80- 1.92 times length of palpomere 1. Legs. Metathoracic legs about 2.60 times HW; length of seta TI4/width of metatibia = 0.77-0.96; length of seta TA2Iwidth of metatarsus = 0.56-0.57. Abdomen (Fig. 67). LLAS = 0.14 mm (n= 1); siphon narrow and acute apically. Urogomphus. Total length of urogomphus = 0.67 rnm (n = 1) [length of urogom- phomere 1 = 0.3 1-0.34 mm (2= 0.33 mm, n = 2)]; 4.81 times LLAS (length of Urol/LLAS = 2.35); Urol/Uro2 = 0.95 (UrolKJro2' = 1.24). Description, Second-instar Larva. No specimen of the second-instar larva was available for description. Description, Third-instar Larva (Fig. 46). As first-instar larva except for the following characters: Colour. Cephalic capsule more predominantly creamy white (Fig. 46); head append- ages, antennomere 3 creamy white; thorax, terga predominantly blackish, with a creamy white lateral stripe on each side; abdomen, terga predominantly blackish, terga 1-5 with pair of creamy white lateral stripes. 436 THE CANADIAN ENTOMOLOGIST MayIJune 1997 Head (Fig. 46). HL = 0.71-0.74 mm (T = 0.73 mm, n = 3); HW = 0.67-0.72 mm (Z = 0.69 mm, n = 3); FCL=0.55-0.58 mm (Y = 0.57 mm, n = 3); cephalic capsule (Fig. 46), FCLIFCW = 2.05-2.13; lateral margin of parietale with two to four temporal spines; maxilla, palpomere 2, 0.89-0.91 times length of palpomere 1; labium, palpomere 2, 1.00- 1.10 times as long as palpomere 1. Legs. Position and number of secondary setae as expressed in Table 5; posterior metatarsal claw 0.55-0.60 times length of metatarsus. Abdomen. LLAS = 0.24-0.27 mm (T = 0.26 mm, n = 3); siphon, 0.13-0.22 times LLAS. Urogomphus. Total length of urogomphus = 1.04-1.06 mm (T = 1.06 mm, n = 3) [length of urogomphomere 1 = 0.42-0.48 mm (Y = 0.44 mm, n = 3)]; 3.91 -4.09 times LLAS (length of UrolLLAS = 1.63- 1.78); UrolJUro2 = 0.71-0.72 (UrolJUro2' = 0.73-0.87). Source of Reared or Associated Material. Eggs were obtained from adults collected at the following locality: CANADA. Alberta. Lundbreck Falls, near Lundbreck, 28.V. 1992. Taxonomic Notes. Oreodytes crassulus is the smallest species among the predominantly dark grey to black species of the 0. obesus species-group (i.e. 0. sierrae, 0. subrotundus, and 0. abbreviatus). Larvae of 0. crassulus are characterized also by the presence of a very narrow and acute siphon (Fig. 67). See also under 0. sierrae. Distribution. The range of 0.crassulus extends from southern Alberta and British Columbia to Colorado, Utah, and California.

Oreodytes sanmarkii (Sahlberg) (Figs. 32,47) Diagnostic Combination. Frontoclypeus broad (Figs. 32,47), with elongate secondary setae dorsoapically (Fig. 47); primary seta AN2 inserted at about level of the ventroapical spinula on antennomere 3 in first-instar larva (Figs. 12,13,15); primary setae MX2, MX3, and MX4 minute (Fig. 6); maxillary stipes lacking additional seta on dorsal surface (Fig. 6); siphon broad, bluntly rounded apically, lacking a notch on lateral margin at about midlength; pale and small species. Redescription, First-instar Larva (Fig. 32). Colour. Cephalic capsule, dorsal surface predominantly creamy white except for short portion of frontoclypeus posteriorly and over parietale, behind ocularium greyish black (Fig. 32); head appendages, predominantly creamy white except antennomere 4, apex of antennomere 3, apex of maxillary palpomere 3 and apex of labial palpomere 2 infuscate; thorax, protergum pale grey (meso- and metaterga missing); legs, predominantly creamy white, lightly infuscate proximally over distal segments; abdomen (terga 1-7 missing), tergum 8 pale grey; urogomphus, urogomphomere 1 creamy white to pale yellow, infuscate over a short distance distally, urogomphomere 2, greyish to black. Head (Fig. 32). HL = 0.49 mm (n = 1);HW = 0.49 mm (n = 1); FCL= 0.38 mrn (n = 1); cephalic capsule (Fig. 32), HW/OcW = 1.56; FCLFCW = 1.91; antenna, A2/A3 = 0.79; antennomere 3 with seta AN2 inserted at about same level of spinula; maxilla, setae MX2, MX3, and MX4 short; maxillary stipes lacking additional seta; labium, palpomere 2, 1.63 times length of palpomere 1. Legs. Length of metathoracic legs/HW, not determined; length of seta TI4lwidth of metatibia = 1.33; length of seta TA2Jwidth of metatarsus = 0.56. Abdomen. LLAS = 0.16 mm (n = 1); siphon rounded to slightly scute apically. Urogomphus. Total length of urogomphus = 0.68 mm (n = 1) [length of urogom- phomere 1 = 0.37 mm (n = I)]; 4.9 1 times LLAS (length of Uro l/LLAS = 2.35); Uro l/Uro2 = 0.92 (Urol/Uro2' = 1.22). Volume 129 THE CANADIAN ENTOMOLOGIST 437 Redescription, Second-instar Larva. As first-instar larva except for the following characters: Colour. Thorax, pro- and mesoterga greyish black, metatergurn creamy white to pale yellow; abdomen, terga 1, 6, and 7 predominantly creamy white to pale yellow (tergum 6 greyish black along anterior margin), terga 2-5 greyish black. Head. HL = 0.66 mm (n = 1); HW = 0.64 mm (n = 1); FCL = 0.53 mm (n = 1); cephalic capsule, FCL/FCW = 2.19; lateral margin of parietale with four temporal spines; maxilla, palpomere 2, 1.12 times length of palpomere 1; labium, palpomere 2, 1.29 times length of palpomere 1. Legs. Position and number of secondary setae as expressed in Table 3. Abdomen. LLAS = 0.25 mm (n = 1); siphon, 0.34 times LLAS. Urogomphus. Total length of urogomphus = 1.06 mm (n = 1) [length of urogom- phomere 1 = 0.48 mm (n = I)]; urogomphus 1.64 times HW (length of Urol/HW = 0.72), and4.32 times LLAS (length of UrolLLAS = 1.96); Urol/Uro2 = 0.83 (Urol/Uro2' = 0.95). Redescription, Third-instar Larva (Fig. 47). As second-instar larva except for the follow- ing characters: Colour. Thorax, terga with a lateral creamy white stripe on each side; abdomen, terga 1-6 with a lateral creamy white stripe on each side. Head (Fig. 47). HL = 0.83-0.84 mm (i! = 0.84 mm, n = 2); HW = 0.77-0.78 mm (Y = 0.78 mm, n = 2); FCL= 0.63-0.65 mm (Y= 0.64 mm, n = 2); cephalic capsule (Fig. 47), FCL/FCW = 1.96-2.02; lateral margin of parietale with temporal spines; maxilla, palpomere 2,0.86-0.90 times length of palpomere 1; labium, palpomere 2,l. 10- 1.17 times as long as palpomere 1. Legs. Position and number of secondary setae as expressed in Table 5; posterior metatarsal claw 0.56-0.57 times length of metatarsus. Abdomen. LLAS = 0.30-0.31 mm (Y = 0.31 mm, n = 2); siphon, 0.15-0.16 times LLAS. Urogomphus. Total length of urogomphus = 1.16- 1.25 mm (Y = 1.20 mm, n = 2) [length of urogomphomere 1 = 0.54-0.55 mm (Y = 0.55 mm, n = 2)]; 3.81 -4.04 times LLAS (length of UrolLLAS = 1.76-1.79); Urol/Uro2 = 0.80-0.86 (Urol/Uro2' = 0.86-0.92). Source of Reared or Associated Material. The larvae studied are loaned specimens (A.N. Nilsson, Umei University) collected in Sweden in association with adults. Taxonomic Notes. Among the species of the 0. obesus species-group, 0. sanmarkii most resembles 0. obesus and 0. congruus, from which it is distinguished by larger size. The range of 0.sanmarkii allows it to be recognized as it is restricted to the western arctic in North America. The close resemblance between 0. sanmarkii and 0. obesus has been discussed previously based on adult morphology (Larson 1990). Distribution. This species has a wide distribution in alpine and arctic regions of the Palearctic. It is known in North America from two localities in the western low arctic (Larson 1990).

Oreodytes obesus (LeConte) (Figs. 12,29,30,51,71) Diagnostic Combination. Frontoclypeus broad (Figs. 29,30,51), with elongate secondary setae dorsoapically (Fig. 51); primary seta AN2 inserted at about level of the ventroapical spinula on antennomere 3 in first-instar lama (Figs. 12); primary setae MX2, MX3, and MX4 minute (Fig. 6); maxillary stipes lacking additional seta on dorsal surface (Fig. 6); siphon broad, bluntly rounded apically, lacking a notch on lateral margin at about midlength (Fig. 71); pale and small species. Description, First-instar Larva (Figs. 12,29, 30). 438 THE CANADIAN ENTOMOLOGIST May/June 1997 Colour. Cephalic capsule, dorsal surface variably coloured, predominantly creamy white, blackish posteriorly behind ocularium (Fig. 29) to more predominantly greyish black, with frontoclypeus, anteriorly and around egg-bursters, and parietale, around ocularium, creamy white (Fig. 30); head appendages, predominantly creamy white, except anten- nomere 4, apex of antennomere 3, apex of maxillary palpomere 3, and apex of labial palpomere 2 infuscate; thorax, protergum greyish black, meso- and metaterga creamy white to pale yellow; legs, creamy white proximally, pale grey distally; abdomen, terga 1-7 pale grey, tergum 8 greyish black; urogomphus, urogomphomere 1 predominantly creamy white, lightly infuscate apically, urogomphomere 2 greyish black. Head (Figs. 12, 29, 30). HL = 0.43-0.48 mm (T = 0.45 mm, n = 9); HW = 0.43-0.48 mm (T = 0.45 mm, n = 9); FCL = 0.31-0.37 mm (F = 0.34 mm, n = 9); cephalic capsule (Figs. 29, 30), HW/OcW = 1.39-1.60; FCLFCW = 1.53-1.79; antenna (Fig. 12), A2/A3 = 0.68-0.79; antennomere 3 with seta AN2 inserted at about same level of spinula; maxilla, setae MX2, MX3, and MX4 short; maxillary stipes lacking additional seta; labium, palpomere 2, 1.51 - 1.84 times length of palpomere 1. Legs. Metathoracic legs about 2.26-2.53 times HW; length of seta TI4lwidth of metatibia = 1.09- 1.48; length of seta TA2/width of metatarsus = 0.52-0.7 1. Abdomen. LLAS = 0.17-0.18 mm (2 = 0.17 mm, n = 9); siphon rounded to acute apically. Urogomphus. Total length of urogomphus = 0.62-0.74 mm (Z = 0.69 mm, n = 9) [length of urogomphomere 1 = 0.30-0.35 mm (Y = 0.32 mm, n = 9)]; 4.72-5.70 times LLAS (length of UrolLLAS = 2.33-2.64); Urol/Uro2 = 0.81-0.94 (Urol/Uro2'= 1.07-1.51). Description, Second-instar Larva. As first-instar larva except for the following characters: Colour. Thorax, mesotergum greyish black; abdomen, terga 1,6, and 7 creamy white to pale yellow, terga 2-5 greyish black, tergum 8 creamy white to pale yellow on anterior half, greyish black posteriorly. Head. HL = 0.55-0.57 mm (T = 0.56 mm, n = 2); HW = 0.58-0.63 mm (Y = 0.60 mm, n = 2); FCL = 0.43-0.44 mm (Y = 0.43 mm, n = 2); cephalic capsule, FCLFCW = 1.75- 1.78; lateral margin of parietale with one to four temporal spines; maxilla, palpomere 2,0.94- 1.02 times length of palpomere 1; labium, palpomere 2,l.10- 1.36 times length of palpomere 1. Legs. Position and number of secondary setae as expressed in Tables 3 and 11. Abdomen. LLAS = 0.17-0.18 mm (F = 0.17 mm, n = 4); siphon, 0.19-0.25 times LLAS. Urogomphus. Total length of urogomphus = 0.80-0.90 mm (Y = 0.84 mm, n = 4) [length of urogomphomere 1 = 0.34-0.38 mm (T = 0.35 mm, n = 4)]; urogomphus 1.27- 1.48 times HW (length of Urol/HW = 0.54-0.59), and 4.61-5.07 times LLAS (length of UrolJLLAS = 1.95-2.12); Urol/Uro2 = 0.67-0.74 (Urol/Uro2' = 0.79-0.89). Description, Third-instar Larva (Figs. 51, 71). As second-instar larva except for the following characters: Colour. Cephalic capsule, more predominantly creamy white (Fig. 5 1); head append- ages, not or more narrowly infuscate over distal segments; thorax, mesotergum black along anterior margin, creamy white to pale yellow posteriorly, terga with a creamy white lateral stripe on each side; legs, predominantly creamy white; abdomen, terga with a creamy white lateral stripe. Head (Fig. 51). HL = 0.70-0.75 mm (Y = 0.72 mm, n = 8); HW = 0.70-0.77 mm (T = 0.73 mm, n = 8); FCL=0.52-0.55 mm (Y=0.53 mm, n = 8); cephalic capsule (Fig. 51), FCLFCW = 1.79-1.95; lateral margin of parietale with three or four temporal spines; maxilla, palpomere 2, 0.76-0.92 times length of palpomere 1; labium, palpomere 2, 0.97- 1.15 times as long as palpomere 1. Volume 129 THE CANADIAN ENTC)MOLOGIST 439 Legs. Position and number of secondary setae as expressed in Tables 5 and 11; posterior metatarsal claw 0.47-0.54 times length of metatarsus. Abdomen (Fig. 71). LLAS = 0.23-0.26 mm (T = 0.24 mm, n = 8); siphon, 0.09-0.23 times LLAS. Urogomphus. Total length of urogomphus = 0.85- 1.02mm (Y= 0.97 mm, n = 8) [length of urogomphomere 1 = 0.34-0.42 mm (Y = 0.38 mm, n = 8)]; 3.76-4.20 times LLAS (length of UrolILLAS = 1.48-1.65); Urol/Uro2 = 0.62-0.73 (Urol/Uro2' = 0.68-0.79). Source of Reared or Associated Material. Eggs were obtained from adults collected at the following localities: CANADA. Alberta. Lundbreck Falls near Lundbreck, 28.V.1992; Yukon Territory. Klondike River Jct of Dempster Hwy and Alaskan Hwy, 25.V.1994; USA. California. Humboltd Co., Redwood Ck, Hwy 101 in Orick, 26.1V.1991 and 21.V.1994; Oregon. Curry Co., Mussel Ck, Hwy 101, 4 km N Ophir, 25.1V.1991 and 12.VI.1991; Washington. Pierce Co., Hall Ck at Hwy 12,2 km W Packwood, 30.V.1995. Taxonomic Notes. Larson (1990) divided 0. obesus into two subspecies: 0. obesus obesus [= 0. rivalis obesus of Zimmerman (1985)l and 0. obesus cordillerensis [O. rivalis rivalis of Zimmerman (1985)l. Geographically, 0. o. cordillerensis has a wide distribution along the Rocky Mountains from Colorado to the central Yukon Territory and west to the Pacific Ocean in British Columbia and Washington, whereas 0. o. obesus is distributed in western California and Oregon (Larson 1990). According to Zirnmerman (1985) the two subspecies hybridize in Washington and northern Oregon. I have been able to rear larvae of population samples of both nominate subspecies of 0. obesus. Unfortunately, most samples were represented by first-instar larvae only. In spite of detailed morphometric (Table 10) and chaetotaxic (Table 11) comparisons, I have been unable to recognize any diagnostic feature to discriminate the larvae of the two subspecies. However, the first-instar larvae of the population sample from the Yukon Territory (0. o. cor- dilllerensis) were found to have a much darker cephalic capsule (Fig. 30) compared with those from California and Oregon (0. o. obesus) (Fig. 29). Additional specimens of 0. o. cordillerensis, including second- and third-instar larvae, are needed to determine whether or not coloration is a useful diagnostic feature. Distribution. See under Taxonomic Notes.

Oreodytes congruus (LeConte) (Figs. 31,50) Diagnostic Combination. Frontoclypeus broad (Figs. 3 1,50),with elongate secondary setae dorsoapically (Fig. 50); primary seta AN2 inserted at about level of the ventroapical spinula on antennomere 3 of first-instar larva (Figs. 12,13,15); primary setae MX2, MX3, and MX4 minute (Fig. 6); maxillary stipes lacking additional seta on dorsal surface (Fig. 6); siphon broad, bluntly rounded apically, lacking a notch on lateral margin at about midlength; pale and small species. Description, First-instar Larva (Fig. 31). Colour. Cephalic capsule, dorsal surface predominantly dark grey to black, except frontoclypeus anteriorly, and parietale, around ocularium, creamy white; head appendages, creamy white, except antennomere 4, apex of antennomere 3, apex of maxillary palpomere 3, and apex of labial palpomere 2 infuscate; thorax, protergum greyish black, meso- and metaterga creamy white to pale yellow; legs, predominantly greyish black, paler over coxae and trochanter; abdomen, terga 1 and 2 pale yellow to pale grey, terga 3-8 dark grey; urogomphus, greyish black. Head (Fig. 31). HL= 0.48 mm (n = 1); HW = 0.49 mm (n = 1); FCL = 0.38 mm (n = 1); cephalic capsule (Fig. 31), HWIOcW = 1.41; FCLFCW = 1.94; antenna, A2lA3 = LbW THE CANADlAN EWOMOLOGIST MayIJune 1997 0.77-0.81; antennomere 3 with seta AN2 inserted at about same level of spinula; maxilla, setae MX2, MX3, and MX4 short; maxillary stipes lacking additional seta; labium, palpomere 2, 1.60- 1.84 times length of palpomere 1. Legs. Metathoracic legs about 2.20 times HW, length of seta TI41width of metatibia = 1.13- 1.25; length of seta TA2lwidth of metatarsus = 0.53-0.7 1. Abdomen. LLAS = 0.13-0.14 mm (Y = 0.14 mm, n = 3); siphon slightly acute apically. Urogomphus. Total length of urogomphus = 0.67-0.70 mm (Y = 0.68 mm, n = 3) [length of urogomphomere 1 =0.28-0.33 mm (Y=0.31 mm, n= 3)]; 4.78-5.35 times LLAS (length of UrolLLAS = 2.10-2.56); Urol/Uro2 = 0.92 (Urol/Uro2' = 1.23-1.34). Description, Second-instar Larva. No specimen of the second-instar larva was available for description. Description, Third-instar Larva (Fig. 50). As second-instar larva except for the following characters: Colour. Cephalic capsule more predominantly creamy white to pale yellow (Fig. 50); thorax, mesotergum greyish black along anterior margin, terga with pair of lateral creamy white stripes; abdomen, terga 1,6, and 7 predominantly yellowish, terga 2-5 predominantly greyish to black, tergum 8 yellowish over anterior half, greyish black posteriorly. Head (Fig. 50). HL = 0.73-0.77 mm (Y = 0.75 mm, n = 3); HW = 0.73-0.78 mm (T = 0.75 mm, n = 3); FCL=0.54-0.58 mm (Y = 0.55 mm, n = 3); cephalic capsule (Fig. 50), FCLFCW = 1.85-1.90; lateral margin of parietale with one to four temporal spines; maxilla, palpomere 2, 0.73-0.86 times length of palpomere 1; labium, palpomere 2, 0.92-0.97 times as long as palpomere 1. Legs. Position and number of secondary setae as expressed in Table 5; posterior metatarsal claw 0.46-0.48 times length of metatarsus. Abdomen. LLAS = 0.23-0.25 mm (T = 0.24 mm, n = 3); siphon, 0.10 times LLAS. Urogomphus. Total length of urogomphus = 0.92-0.94 mm (Y = 0.93 mm, n = 3) [length of urogomphomere 1 = 0.35-0.40 mm (T = 0.37 mm, n = 3)]; 3.99-4.08 times LLAS (length of UrolLLAS = 1.54-1.61); Urol/Uro2 = 0.60-0.63 (Urol/Uro2' = 0.66-0.85). Source of Reared or Associated Material. Eggs were obtained from adults collected at the following localities: USA. California. Siskiyou Co., Jackson Ck, 12 krn W Callahan on Cecilville Road, 20.V.1994; Oregon. Curry Co., Mussel Ck, Hwy 101, 4 km N Ophir, 25.1V.1991 and 12.VI.1991. Taxonomic Notes. Larvae of 0.congruus are similar morphologically to those of 0.obesus and I was unable to find any features to distinguish them. As both species are sympatric in part of their ranges, larvae may be confused one with another. Distribution. Oreodytes congruus is distributed from western Alberta and central British Columbia, south to New Mexico and California.

CHARACTER ANALYSIS The classification and reconstructed phylogeny were prepared using cladistic methods which have been copiously reviewed elsewhere (Ross 1974; Eldredge and Cracraft 1980; Wiley 1981; Ax 1987; Wiley et al. 1991; MaddisonandMaddison 1992; Quicke 1993; Forey et al. 1994). For phylogenetic analysis and its interpretation, the computer program MacClade (version 3.04) (Maddison and Maddison 1992) was used. Character states were generally polarized through out-group comparison (Watrous and Wheeler 1981) with 36 species from eight genera belonging to the tribe Hydroporini (Table 12) (char. 06 was polarized by in-group comparison). Estimates of relationships of Oreodytes and other hydroporine genera are not formulated adequately yet. Although a close phylogenetic relationship has been proposed recently between Oreodytes and the Palearctic volume 129 THE CANADIAN ENTOMOLOGIST 44 1 genera Neonectes and Deronectes (Alarie and Nilsson 1996,1997; Alarie et al. 1996),neither of these genera can be used as an out-group because Neonectes probably belongs within the genus Oreodytes (see Discussion) and larvae of Deronectes still are unknown. To overcome this problem, I have chosen to consider the genus Hydroporus Clairville as a suitable out-group. Recent works on larval morphology of members of this genus (Alarie 1991a, 1992,1995) suggest that it represents a basal lineage of the tribe Hydroporini. Decisions on the phylogenetic polarity were also based on comparisons with larvae of the genus Laccornis Des Gozis which has been suggested many times as the sister-group of all other Hydro- porinae (Wolfe 1985, 1989; Nilsson 1988; Alarie and Harper 1990). The character matrix proposed in this paper consisted of 27 binary and two three-state characters [one treated as ordered, the other (char. 08) as unordered]. Eight characters were from the head, eight from the cephalic appendages, five from the thorax, and eight from the last abdominal segment and urogomphi. The autapomorphies were retained. In the discus- sion below, characters are listed by number. States are coded to reflect hypothesized polarity and sequence from the plesiomorphic condition (state 0); apomorphic states are indicated by 1 or 2. The rationale for character polarity assessment is given for each character. Cephalic Capsule. Character 01. Occipital suture. Two states: 0, absent; 1, present. In all Hydroporinae, the cephalic capsule of second-instar larvae has an occipital suture. Absence of an occipital suture in first-instar larvae of more basic lineages such as Laccornis and Hydroporus suggests that this condition is plesiomorphic. First-instar larvae of Oreodytes have an occipital suture (Figs. 1,2,21-34). Accordingly, this condition is deemed to be apomorphic within Hydroporini. Character 02. Parietale. Two states: 0, not constricted; 1, constricted. Within Oreodytes the parietale is constricted at the level of the occipital suture (Figs. 1, 2, 21-51). Such constriction is lacking both in Laccornis and most of the Hydroporine species studied (except Nebrioporus and Stictotarsus which are characterized by a slight constriction). The presence of a constriction posterolaterally on the parietale is postulated to be apomorphic. Character 03. Pore PAd. Two states: 0, present; 1, absent. The groundplan condition of the parietale in the subfamily Hydroporinae comprises five primary pores including pore PAd (Alarie 1991b). Absence of pore PAd in all Oreodytes (Figs. 1,2,21-34) is considered apomorphic. Character 04. Pore PAe. Two states: 0, present; 1, absent. The rationale for polarity of this character is similar to the previous one. As pore PAe was included in the groundplan pattern of the subfamily Hydroporinae, its absence within Oreodytes (Figs. 1, 2, 21 -34) is considered apomorphic. Character 05. Frontoclypeus. Two states: 0, elongate; 1, short. Larvae of Hydroporinae differ from other Dytiscidae by the elongation of the frontoclypeus into a nasale. The ratio HL/HW has been generally used as an index for the relative elongation of the frontoclypeus. Larvae of Oreodytes differ from other Hydroporini by a shorter frontoclypeus. In first-instar larvae, HLIHW is generally lower than 1.10 compared with more than 1.20 in the other species studied (Figs. 1, 2, 21-34). A more elongate frontoclypeus is thus considered plesiomorphic and, accordingly, the condition observed within Oreodytes is deemed to be apomorphic. Character 06. Frontoclypeus. Two states: 0, broad; 1, narrow. The frontoclypeus of most species of the genus Oreodytes is moderately variable in width. The ratio FCL/FCW was used in this study as an index of shape for the frontoclypeus. In third-instar larvae, this ratio varies from 1.80 to 2.40 in all species of Oreodytes except 0.subrotundus. This latter species has avery narrow frontoclypeus (FCL/FCW = 3.20) (Figs. 27,49). Based on in-group comparison, the narrow frontoclypeus is an autapomorphy for 0. subrotundus. Character 07. Lamellae clypeales. Two states: 0, lacking a medial gap; 1, with a medial gap. First-instar larvae of most members of the Hydroporinae are characterized by more or less numerous club-shaped setae (lamellae clypeales) located in a single uninterrupted row along the ventroapical margin of the frontoclypeus and this is postulated to be the plesio- morphic condition. Members of the quadrimaculatus, picturatus, and scitulus species- groups have a medial gap in the row of lamellae clypeales (Fig. 2) which is considered a derived trait. Although observed in some specimens of 0. sierrae and 0. sanmarkii, such a gap is lacking within members of the obesus-species group. Character 08. Temporal spines. Three states: 0, numerous, spine-like, acute apically; 1, numerous, spine-like, bluntly rounded apically; l', few, seta-like, acute apically. The second- and third-instar larvae of members of the subfamily Hydroporinae generally have abundant spine-like secondary setae on the lateral margin of the parietale. The setae are called temporal spines and differ from all other secondary setae by their spine-like appearance (Figs. 36-44). Larvae of the 0.picturatus species-group are unique among Hydroporinae in that the temporal spines are bluntly rounded apically (Fig. 35). This feature is postulated to be derived. Members of the 0.obesus species-group have only a few more seta-like spines (Figs. 45-51). This condition is also recognized as apomorphic although it is postulated to have evolved independantly from the condition found in the 0.picturatus species-group. Head Appendages. Antenna. Character 09. Antennomere 3. Two states: 0, spinulae lacking; 1, spinulae present. Larvae of Oreodytes have minute ventroapical spinulae on antennomere 3 (Figs. 3,12-20). These spinulae are lacking in Laccornis. Presence of spinulae is thus postulated to be apomorphic. Character 10. Pore ANf. Two states: 0, present; 1, absent. Pore ANf on antennomere 3 is consistently present among the basal lineages of the tribe Hydroporini. Accordingly, its absence within most species of Oreodytes (Figs. 12- 19) is viewed as a derived trait. Based on the principle of parsimony, the presence of pore ANf in 0. quadrimaculatus (Fig. 20) must be considered a reversal from the derived condition. Character 11. Lateral projection of antennomere 3 (A3'). Two states: 0, A3'/A4 2 0.60; 1,A3'/A4 < 0.50. In all Hydroporinae, antennomere 3 is characterized by a lateral projection (A3') which varies in length among species. The ratio A3'/A4 is used as an index to express the relative elongation of A3'. The ratio A3'/A4 is over 0.60 in all basal lineages of Hydroporini and Laccornis. Accordingly, this condition is deemed to be plesiomorphic. Within Oreodytes,A3'/A4 is consistently lower than 0.50 (Figs. 3,4,12-20) and is regarded an apomorphic feature. Head Appendages. Maxilla. Character 12. Cardo. Two states: 0, present; 1, absent. Within most members of the subfamily Hydroporinae, the maxilla is characterized by the presence of a small rounded cardo posterior to the stipes and the presence of the cardo is deemed to represent the groundplan condition. The maxillary cardo is lacking in Oreodytes (Figs. 7,ll). This feature is postulated to be apomorphic. Character 13. Seta MX1. Two states: 0, inserted on the cardo; 1, inserted on the stipes. The insertion of seta MX1 on the maxillary cardo is the groundplan condition of the subfamily Hydroporinae. It has been suggested that the absence of the maxillary cardo in Oreodytes might result from the apparent fusion of the cardo with the maxillary stipes (Alarie 1991b), which might explain the presence of seta MX1 on the maxillary stipes in these species. If this interpretation is correct then this character is equivalent to the previous one. However, as larvae of the Hydroporinae are still badly known, 1 prefer to wait and treat these two characters as separate. The presence of seta MX1 inserted on the maxillary stipes (Figs. 7, 11) is postulated to be apomorphic. Volume 129 THE CANADIAN E~TOMOLOGIST 443 Character 14. Seta MX5. Two states: 0, present; 1, absent. The groundplan pattern of primary setae proposed for the maxilla of the Hydroporinae includes five dorsal setae on the maxillary stipes among which is seta MX5. Absence of seta MX5 in all species of Oreodytes is postulated to be a derived trait (Figs. 7, 11). Character 15. Setae MX2, MX3, and MX4. Two states: 0, minute; 1, elongate. Within the Hydroporinae, three primary setae (MX2, MX3, and MX4) are located on the dorsal surface of the maxillary stipes. These setae are minute throughout the subfamily including most species of Oreodytes (Fig. 6) except in 0.subrotundus (Fig. 10) where the presence of very elongate primary setae is regarded as an evolutionary novelty. Character 16. Stipes. Two states: 0, lacking additional seta; 1, with one additional seta. As stated above, there are three primary setae inserted dorsally on the maxillary stipes (MX2, MX3, and MX4) (Fig. 6). Larvae of 0.subrotundus are unique among Oreodytes as an additional elongate seta is also found on the stipes (Fig. 10).This seta cannot be homologized with primary seta MX5 as it is located at a different position. Thorax. Character 17. Maximum body width. Two states: 0, narrow; 1, broad. Larvae of the subfamily Hydroporinae are characterized by a fusifonnate body shape. Within Oreodytes two distinct patterns are observed. Members of the obesus species-group are characterized by a very broad body shape (MBWILASW > 4.20 in third-instar larva). In comparison, the body is narrow in all other species of Oreodytes (MBW/LASW = 2.80-3.00) and comparable in shape to that observed throughout the tribe Hydroporini as well as in the genus Laccornis. Accordingly, the broad body width of the 0.obesus species-group is considered apomorphic. Although slightly broader than members of both the 0.quadrimaculatus and 0.scitulus species-groups, members of the 0.picturatus species-group were deemed to be plesiomor- phic in body width. Character 18. Tibia and tarsi. Two states: 0, spinulae present; 1, spinulae absent. The genus Laccornis as well as most Hydroporini are characterized by the presence of spinulae along the ventral edge of the tibiae and tarsi. These spinulae are generally more strongly developed on both pro- and mesothoracic legs of the first-instar larva. Marginal spinulae, which are deemed to represent the plesiomorphic condition, occur also among many species of Oreodytes (Figs. 52-59) except those of the 0.obesus species-group (Figs. 60,61). Such character state is here considered a derived trait. Character 19. Tibiae. Two states: 0, absence of an elongate secondary seta; 1, presence of an elongate secondary seta. Within the tribe Hydroporini, the second- and third-instar larvae are generally characterized by the presence of a variable number of secondary setae of subequal length. Members of Oreodytes differ from this groundplan pattern by the presence of a more elongate secondary seta occurring on the dorsal margin of each tibiae (Figs. 55, 57, 59, 61). This feature is deemed to represent an evolutionary novelty within Hydroporini. This elongate seta should not be compared with the so-called natatory setae of some hydroporine genera. Although located at a similar position, natatory setae are more elongate and hair-like. Character 20. Tarsi. Two states: 0, secondary setae absent; 1, secondary setae present. Within Oreodytes, the secondary setae are generally lacking on the tarsi (Figs. 58-61). A similar condition is observed in Laccornis and accordingly this is viewed as plesiomorphic. Presence of secondary tarsal setae in 0.quadrimaculatus (Figs. 54,55) (Tables 2 and 4) and in some species of both the 0. scitulus (Figs. 56, 57) (Tables 2 and 4) and 0. obesus species-groups (Tables 3 and 5) suggests that this character state evolved many times independently within Oreodytes. Character 21. Secondary setae on legs. Two states: 0, not abundant; 1, abundant. The ontogenetic development of the dytiscid larva is characterized by the addition of a variable number of secondary setae on the legs. Within the subfamily Hydroporinae, it has been 444 THE CANAMAN ENlVMOtOGI.Ff MayIJune 1997 suggested that larvae showing a majority of other plesiomorphic character states also have few secondary setae on legs (Nilsson 1988). Most of the species of Oreodytes studied were found to be fairly similar regarding the number of secondary setae on the legs (Tables 2-5). However, 0.quadrimaculatus differs in that a significantly higher number of secondary setae occur (compare Figs. 54,55 and Figs. 56,61). Based on the assumption that reduced setation is plesiomorphic, the condition observed for 0.quadrimaculatus is deemed to be apomorphic. Abdomen. Character 22. Pore ABa. Two states: 0, present; 1, absent. The ancestral system of setae and pores on the last abdominal segment proposed for the Hydroporinae includes a dorsal pore on the anterior portion of the segment (pore ABa) (Alarie and Harper 1990). This pore is consistently lacking in Oreodytes (Figs. 62-68) and other Hydroporinae except Laccornis and is viewed as a derived trait. Character 23. Abdomen segments 7 and 8. Two states: 0, bluntly rounded secondary setae absent; 1, bluntly rounded secondary setae present. Within the Hydroporinae, second- and third-instar larvae are characterized by the presence of a variable number of secondary setae on the abdominal segments. Those secondary setae are generally spine-like and always acute apically (Figs. 69-71). Members of the 0.picturatus species-group differ from the groundplan condition in that a few bluntly rounded secondary setae occur both on the penultimate and the last abdominal segment (Fig. 72). This condition is considered to represent an evolutionary novelty for this species-group. Urogomphus. Character 24. Urogomphomere 1. Two states: 0, secondary setae absent; 1, secondary setae present. The groundplan condition of the dytiscid urogomphus includes eight primary setae (Alarie and Harper 1990). In many species of Hydroporini, no secondary setae are added during the ontogenetic development of the larva and this is viewed as plesiomorphic. Within Oreodytes, every species develops several secondary setae on urogomphomere 1 (Figs. 77-81). This character state is deemed to be apomorphic. Character 25. Secondary setae. Two states: 0, acute apically; 1, bluntly rounded apically. The secondary setae found on urogomphomere 1 of larvae of Oreodytes are generally spine-like and acute apically (Figs. 77,78, 80, 81) which is the general condition for these setae within Dytiscidae. Larvae of 0.angustior are very unique in this regard as several bluntly rounded secondary setae occur on urogomphomere 1 (Fig. 79). This condition represents a highly derived feature in Oreodytes. Character 26. Additional pore. Two states: 0, absent; 1, present. The groundplan condition of the Hydroporinae urogomphus includes three pores on urogomphomere 1 (Figs. 74, 76). Members of the 0.picturatus (Fig. 76) and 0. scitulus (Fig. 73) species- groups differ from the groundplan pattern as an additional pore occurs on urogomphomere 1. This feature is viewed as apomorphic. Character 27. Position of seta UR8. Two states: 0, terminal; 1, subapical. A gradual transformation series was depicted for the point of insertion of the primary seta UR8 in the subfamily Hydroporinae (Alarie and Harper 1990). Seta UR8 shows a gradual transforma- tion from terminal in position in the genus Laccornis, which represents the plesiomorphic condition, to proximal in the more evolved genus Desmopachria Babington. Seta UR8 is subapical in genera such as Hydroporus, Neoporus, and Heterosternuta whereas it is more medial in the genus Hygrotus. Seta UR8 is subapical in first-instar larvae of most species of Oreodytes (Figs. 73-75). Members of the 0.picturatus species-group are very peculiar as seta UR8 occupies a terminal position (Fig. 76). This condition is regarded as a reversal to the plesiomorphic character state. Volume 129 THE CANADIAN ENTOMOLOGIST 445 Character 28. Urogomphus. Three states: 0, short, urogomphomere 1 subequal to urogomphomere 2 in length; 1, elongate, urogomphomere 1 subequal to urogomphomere 2 in length; 2, elongate, urogomphomere 1 more than 2.00 times as long as urogomphomere 2. Larvae of the subfamily Hydroporinae are characterized by a two-segmented urogomphus. The presence of a very short urogomphus in more basic lineages such as Laccornis, Celina AubC, and Canthyporus Zimmermann suggests that this condition is plesiomorphic within Hydroporinae. Interpretation of the transformation sequence in the relative length of the urogomphus of Hydroporini is somewhat difficult to assess especially if the urogomphus is compared with other structures characterized by a significant intraspecific variability (e.g. the last abdominal segment). Accordingly, I have chosen to compare the length of the urogomphus with HW which was found to be a less variable measurement (as reflected by the range of values of the ratio HL/HW). Members of Oreodytes may be subdivided into three different groupings in regard to the relative length of the urogumphus: species of the 0.obesus species-group are charac- terized by a relatively short urogomphus (1.40- 1.60 times HW in first-instar larvae) with urogomphomere 1 subequal to urogomphomere 2 in length (state 0) (Fig. 74); members of the 0.quadrimaculatus species-group show a more elongate urogomphus (2.20 times HW) with urogomphomere 1 subequal to urogomphomere 2 in length (state 1) (Fig. 75); finally, species of both the 0.picturatus and the 0.scitulus species-groups evolved a more elongate urogomphus (1.90-2.60 times HW) with urogomphomere 1 about 2.00 times as long as urogomphomere 2 (state 2) (Figs. 73,76). Character 29. Seta AB5. Two states: 0, short; 1, elongate. Hydroporine larvae are characterized by the presence of three primary setae (AB4, AB5, AB6) inserted proximally on the siphon (Fig. 62). These setae are generally short and never extend beyond the apex of the siphon (Figs. 64-66). Members of the 0.obesus species-group are unique among Hydroporinae in that primary seta AB5 is very elongate and extends well beyond the apex of the siphon (Figs. 67, 68). This feature is deemed to represent a derived trait within Oreodytes.

PHYLOGENETIC ANALYSIS

This paper represents the first attempt at revising the taxonomy of a genus of Hydradephaga based solely on larval morphology. Twenty-nine morphological characters were used in the phylogenetic analysis to resolve the relationships of the species of Oreodytes (Table 13). The phylogeny proposed here is presented in Figure 82. As expressed by the high value of the statistics obtained (C.I. = 0.89; R.I. = 0.93), the data were relatively clean (i.e. free from homoplasy).

Generic Relationships within Hydroporini. The tribe Hydroporini comprises more than 30 genera worldwide (Pederzani 1995). In spite of recent efforts (Alarie 1991a, 1991b, 1992, 1995; Alarie and Harper 1990; Alarie et al. 1990a, 1990b), the number of genera for which larvae have been described still remains fairly low which hampers considerably any attempt at phylogenetic reconstruction. However, Alarie and Nilsson (1997) have recently proposed a phylogeny including 11 genera of Hydroporini. As the cladogram generated in that study was based on larval features and included the genus Oreodytes, no cladogram aiming at depicting the phylogenetic relationships of Oreodytes with other hydroporine genera is presented. The cladogram (Fig. 82) presented in my study suggests a monophyletic origin for the lineage Oreodytes. However, this hypothesis must be discussed in a more general way as many of the synapomorphies resulting from the character analysis are also shared with some other genera of the tribe Hydroporini. Based on the actual knowledge of larval morphology of Hydroporini, it seems likely that members of Oreodytes share a monophyletic origin 446 THE CANADIAN ENTOMOLOGIST MayIJune 1997 with those of Hygrotus, Hydroporus, H. oblitus species-group, Sanfilippodytes, Neoporus, Heterosternuta, Nebrioporus, and Stictotarsus. All members of this clade are characterized by the following: (i) the absence of pore PAd on the parietale (char. 03) (Fig. 1); (ii) the absence of pore ABa on the dorsal surface of abdomen segment 8 (char. 22) (Fig. 62); and (iii) the subterminal position of primary seta UR8 on urogomphomere 2 (char. 27) (Figs. 73- 75). The genus Hygrotus stands out as the sister-group of the remaining taxa which share four synapomorphies:(i) the absence of primary pore PAe (char. 04) (Fig. 1); (ii) the presence of a ventroapical spinula on antennomere 3 (char. 09) (Figs. 3, 12-20); (iii) the absence of primary seta MX5 (char. 14) (Figs. 6,7, 10, 11); and (iv) the more apical position of primary seta UR8 on urogomphomere 2 (char. 27) (Figs. 73-76) [recent papers dealing with some genera of the subfamily Hydroporinae have shown that a gradual transformation series may be depicted for the point of insertion of primary seta UR8 and that this primary seta is more medially inserted in the genus Hygrotus (Alarie and Harper 1990; Alarie et al. 1990b)l. A monophyletic origin is proposed for the genera Oreodytes, Stictotarsus, and Nebrioporus. These genera share the following derived character states: (i) the presence of an occipital suture from the first-instar larva (char. 01) (Figs. 1,21-34); (ii) the presence of at least a slight constriction at the level of the occipital suture (char. 02) (Figs. 1, 21 -51); (iii) the absence of primary pore ANf on antennomere 3 (char. 10) (Figs. 3,4,12- 19); (iv) the relatively shorter elongation of the lateral projection of antennomere 3 (A3') (char. 11) (Figs. 3, 4, 12-20); (v) the absence of a maxillary cardo (char. 12) (Figs. 7, 11); (vi) the insertion of primary seta MXl on the maxillary stipes (char. 13) (Figs. 7, 11); and (vii) the presence of secondary setae on urogomphomere 1 (char. 24) (Figs. 77-81). Among these features, characters 10 and 24 appear to be less meaningful phylogenetically as both are homoplastic; within Hydroporini, primary pore ANf (char. 10) is lacking in Hygrotus and secondary setae on urogomphomere 1 (char. 24) are known to occur as well in Heteroster- nuta, Neoporus, and part of Hygrotus (Alarie et al. 1990b; Alarie 199la, 1991b). The presence within the Palearctic genera Deronectes and Scarodytes Gozis of an occipital suture in first-instar larvae (Nilsson and Angus 1992) should be regarded as a strong argument supporting a phylogenetic relationship of these genera with Oreodytes, Nebrioporus, and Stictotarsus. Because of this relationship, it is hypothesized that both Deronectes and Scarodytes might be characterized also by the absence of a maxillary cardo, the presence of primary seta MX1 on the maxillary stipes, and a shorter elongation of the lateral projection of antennomere 3. Within the clade comprising Oreodytes + Deronectes + Scarodytes + Stictotarsus + Nebrioporus, it is suggested that Oreodytes and Deronectes occupy a more basal position because both genera lack secondary natatory setae on the legs (Alarie and Nilsson 1997). At present, the monophyletic origin of the genus Oreodytes may be supported only by two shared derived character states: (i) the short frontoclypeus (char. 05) (Figs. 1, 21-51); and (ii) the presence of a very elongate secondary seta on the dorsal margin of the tibiae (char. 19) (Figs. 55, 57, 59, 61). An additional putative feature in favour of this hypothesis would have been the lack of spinulae on the lateral margin of the prementum (Figs. 8, 9). Labial spinulae are generally present among members of the Hydroporini. However, the interpretationof the polarity for this character state is conflictual as labial spinulae are lacking in Laccornis. It is suggested that this feature might represent a reversal from the derived condition within Oreodytes (Alarie and Nilsson 1997). Relationships within Oreodytes. As a result of the character analysis presented here, species of Oreodytes may be subdivided into two monophyletic lineages: one includes members of the 0. obesus species-group; the other encompasses the three other species-groups recog- nized in this paper: the 0. quadrimaculatus, 0. picturatus, and 0. scitulus species-groups. The 0.obesus species-group as a monophyletic unit. Seven species are included in this species group: 0. obesus, 0. congruus, 0. sanmarkii, 0. crassulus, 0. abbreviatus, Volume 129 THE CANADIAN ENTOMOLOGIST 447 0. sierrae, and 0. subrotundus. The larvae of these species are characterized by the following: (i) the presence of only a few seta-like temporal spines (char. 08) (Figs. 45-51); (ii) the broad fusiformate body shape (char. 17); (iii) the absence of spinulae on the ventral margin of the tibiae and tarsi (char. 18) (Figs. 60,61); and (iv) the presence of a very elongate primary seta AB5 on the siphon (char. 29) (Figs. 67,68). Among these species, the larvae of 0. subrotundus are remarkably modified with three striking and peculiar features: (i) the presence of a very narrow frontoclypeus (char. 06) (Figs. 27,49); (ii) the presence of very elongate primary setae MX2, MX3, and MX4 (char. 15) (Figs. 10); and (iii) the presence of a very elongate additional seta on the maxillary stipes (char. 16) (Fig. 10). The presence of secondary setae on tarsi of 0. subrotundus is noteworthy (char. 20) although it seems likely that this feature evolved many times independently within Oreodytes (in 0. laevis, 0. sno- qualmie, 0. recticollis, and 0. quadrimaculatus). No synapomorphy was found to substan- tiate a monophyletic origin for other members of this species-group. However, as their larvae are remarkably similar morphologically, it is hypothesized that they share a common origin. The 0. quadrimaculatus + the 0. picturatus + the 0. scitulus species-group as monophyletic unit. Based on larval morphology, the 0. quadrimaculatus, 0. picturatus, and 0. scitulus species-groups should be viewed as the sister-group of the 0. obesus species-group (Fig. 82). These groups form a monophyletic assemblage which is supported by two synapomorphies: (i) the presence in first-instar larvae of a medial gap in the row of lamellae clypeales (char. 07) (Fig. 2); and (ii) the presence of a very elongate urogomphus (char. 28.1) (Figs. 73, 75, 76). Within this clade, 0. quadrimaculatus stands out as the sister-group of a lineage comprising members of both the 0. picturatus and 0. scitulus species-groups (Fig. 82). The 0.quadrimaculatus species-group. The larvae of 0.quadrimaculatus are distinc- tive among Oreodytes. As a member of the monophyletic unit comprising the 0. quadri- maculatus + 0.picturatus + 0. scitulus species-group, this species is characterized by the following: (i) the presence of several secondary setae on the legs (char. 21) (Figs. 54,55); and (ii) the presence of secondary setae on the tarsi (char. 20) (Figs. 54,55). However, the latter feature should be viewed as homoplastic (see below). Oreodytes quadrimaculatus represents a strange element in regard to the presence of primary pore ANf on antennomere 3. This pore is lacking in the groundplan condition of Oreodytes, Nebrioporus, and Stictotarsus. Accordingly, it seems likely that its presence in 0. quadrimaculatus results more from a reversal from the derived condition. The 0. picturatus and 0.scitulus species-groups as a monophyletic unit. The larvae of the 0. picturatus and 0. scitulus species-groups are very similar based on larval morphology. Structurally, these larvae share two derived character states: (i) the presence of an additional pore on urogomphomere 1 (char. 26) (Figs. 73,76); and (ii) the presence of an elongate urogomphus with urogomphomere 1 more than 2.00 times as long as urogom- phomere 2 (char. 28.2) (Figs. 73,76). Within this clade, the 0.picturatus species-group stands out as a distinct monophyletic unit which is supported by two synapomorphies: (i) the presence of several bluntly rounded temporal spines (char. 08') (Fig. 35); and (ii) the presence of bluntly rounded secondary setae on abdomen segments 7 and 8 (char. 23) (Fig. 72). Members of this species-group are unique among Hydroporini as here primary setaUR8 is inserted terminally on the urogomphus (char. 27) (Figs. 76,78), a reversal from the derived condition. No larval synapomorphy was found to substantiate a monophyletic origin for members of the 0. scitulus species-group. However this hypothesis seems to be supported based on adult features (Zimmerman 1985) (characters not represented in Fig. 82). The 0.picturatus species-group. The 0.picturatus species-group comprises two very similar species. The larvae of 0. angustior are unique among Hydroporini in that they are THE CANADIAN ENTOMOLOGIST Mayfiune 1997 characterizedby the presenceof a few bluntly rounded secondarysetae on urogomphomere I (char. 25) (Fie.19).

DISCUSSION

As more and more larvae become known, it is worthwhile to attempt to reconcile the affinities of the larvaewith thoseof the correspondingadults. When animalscan be arranged in groups that are compatible with both adult and larval characters,this provides a strong indication that the adults and larvae concemedhave evolved together,as different phasesin the samelife history, and the resulting classificationis more likely to provide a true reflection of phylogeny than one that ignores the larvae (Williamson 1992). The classification indicated by larval Oreodytesis only partly reconcilablewith the one indicated by adults. In his revision of adults, Zimmerman (1985) subdivided the genus Oreodytesinto three species-groups(the O. quadrimaculatus, O. angustior, andO. scitulus species-groups)and proposed O. quadrimaculalrrs as the sister-group of the remaining speciesof Oreodytes.As defined in this paper,the O . obesusspecies-group encompasses the speciesformerly included in the O. angustior species-groupof Zimmerman minus O. pic- turatus andO. angustior. The larvaeofboth thesespecies differ strongly from the groundplan pattem of members of the O. obesusspecies-group. The sharedpresence of an additional pore on urogomphomere I (Fig. 76), the presenceof a medial gap in the row of lamellae clypeales(Fig.2), as well as the typical shapeof the urogomphus(Fig. 76) strongly support the hypothesis that O . picturatus andO . angustior are more closely relatedphylogenetically to members of the O. scitulus species-group than to any other species of Oreodytes. Accordingly, on the basis of larval morphology, there is no doubt that the O. angustior species-groupof Zimmerman (1985) is polyphyletic. Members of the O. picturatus species-groupsurely representstrange elements among Oreodytes.The occurrenceof typically bluntly rounded secondarysetae over certain body structures (Figs. 35, 72, 19) is a highly derived feature which sffongly supports a mono- phyletic origin for O . picturatus and O . angustior. Guignot (1945) noticed such a morpho- logicai peculiarity for adults of O. picturalas becausethis specieswas elected by him to represent the type species of the genus Deutronectes ffunior subjective synonym of Oreodytes(Nilsson et at. 1989)1. The relative position occupied by O. quadrimaculatus is also noteworthy. Based on larval morphology, this species should be considered as the sister-group of the lineage comprising the O. picturatus + the O. scitulus species-groups(Fig. 82) which contradicts the hypothesisformulated by Zimmerman (1985). However, Zimmerman was uncertain as to its placementas indicated by his statement:"unless O. quadrimaculatus cn be shown to be more closely related to some other species of Hydroporlzs, it is better to keep it in Oreodytesrather than creating a new weakly differentiated genus" (1985, pp. 123-124). There is no doubt that O. quadrimaculalas is more similar to members of both the O . picturatus andO . scitulus species-groupsthan to those of the obesusspecies-group. This relationship is well substantiatedby the sharing of two larval derived features(char. b7 and 28). No% does O. quadrimaculatus really belong to the genus Oreodytes? Unless the monophyletic oigin of Oreodytesis demonstrated,this question cannot be resolved.Based on my study, there are some indications that the species assignedto Oreodytes share a monophyletic origin, i.e. the presenceof a very elongatesecondary seta on the dorsal margin of the tibiae(Figs. 55, 5l ,59,61) aswell asa relativelyshort frontoclypeus (Figs. l,2l-51). However, the determination of the monophyly of the genus Oreodytesis hamperedby the uncertainty in identification of its sister-group. It seems likely that the Palearctic genus Deronectes might represent the sister-group of Oreodytes. Unfortunately, the larvae of D eronectesare unknown. Volume 129 THE CANADlAN WOMOLOGIST 449 Except for 0. subrotundus, which has a surprisingly large number of apomorphic characters, the species within each of the 0.obesus and 0.scitulus species-groups are similar morphologically among themselves. The lack of larval character states within those two branchings suggests a relatively recent and rapid evolution of these species which is generally recognized as typical of the western montane insect fauna of North America (Noonan 1992). The morphological study of the larvae of Oreodytes provided in my paper leads to a comparison with the larvae of the Palearctic genus Neonectes. The taxonomic status of this genus was questioned recently to decide if Neonectes should be considered as a subgenus of Oreodytes or as a distinct genus (Alarie and Nilsson 1996). The larvae of N. natrix (Sharp) (Alarie and Nilsson 1996) and N. babai Sat6 (Alarie et al. 1996) have been described recently. It is obvious that both these species are closely similar to the species comprising the 0. scitulus species-group. All these species share the following: (i) the presence of a medial gap in the row of lamellae clypeales (char. 07) (Fig. 2); (ii) the presence of an additional pore on urogomphomere 1 (char. 26) (Figs. 73, 76); and (iii) the presence of a very elongate urogomphus with urogomphomere 1 distinctly longer than urogomphomere 2 (char. 28.2) (Figs. 73, 76).

ACKNOWLEDGMENTS I am deeply grateful to to R.E. Roughley (University of Manitoba, Canada) who assisted me in the field in 1991 and 1992. I also owe much gratitude to A.N. Nilsson (Umeii University, Sweden) who provided me with specimens of 0. sanmarkii, 0. septentrionalis, and 0.alpinus. Finally, special thanks to my wife, Lucie, for her constant support throughout the making of this paper. Much time and energy otherwise available for family life has been given to this paper thus making Lucie's task heavier than it normally would have been. Financial support was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC) in the form of an operating research grant and an equipment grant. The 1991 and 1992 field trips were funded through a NSERC research grant to R.E. Roughley and a NSERC Postdoctoral Fellowship to Y. Alarie.

REFERENCES Alarie, Y. 1989. The larvae of Laccornis Gozis 1914 (Coleoptera: Adephaga: Dytiscidae) with a description of L. latens (Fall, 1937) and a redescription of L. conoideus (LeConte, 1850). The Coleopterists Bulletin 43: 365-378. -1991~. Description of larvae of 17 Nearctic species of Hydroporus Clairville (Coleoptera: Dytiscidae: Hydroporinae) with an analysis of their phylogenetic relationships. The Cananadian Entomologist 123: 627-704. -19916. Primary setae and pores on the cephalic capsule and head appendages of larval Hydroporinae (Coleoptera: Dytiscidae). Canadian Journal of Zoology 69: 2255-2265. 1992. Description of the larval stages of Hydroporus (Heterosternuta) cocheconis Fall 1917 (Coleoptera: Dytiscidae: Hydroporinae) with a key to the known larvae of Heterosternuta Strand. The Canadian Entomologist 124: 827-840. 1993. A systematic review of the North American species of the Oreodytes alakanus clade (Coleoptera: Dytiscidae: Hydroporinae). The Canadian Entomologist 125: 847-867. -1995. Description of the larval stages of Hydroporus (s. str.) dentellus Fall 1917 (Coleoptera: Dytiscidae: Hydroporinae). The Coleopterists Bulletin 49: 157- 168. Alarie, Y., and P.-P. Harper. 1990. Primary setae and pores on the last abdominal segment and the urogomphi of larval Hydroporinae (Coleoptera: Adephaga: Dytiscidae), with notes on other dytiscid larvae. Canadian Journal of Zoology 68: 368-374. Alarie, Y., P.-P. Harper, and A. Maire. 1989. Rearing dytiscid beetles (Coleoptera: Dytiscidae). Entomologica Basiliensa 13: 147- 149. 1990a. Primary setae and pores on legs of larvae of Nearctic Hydroporinae (Coleoptera: Dytiscidae). Quaestiones Entomologicae 26: 199-210. Alarie, Y., P.-P. Harper, and R.E. Roughley. 19906.Description of the larvae of eleven Nearctic species of Hygrotus Stephens (Coleoptera: Dytiscidae: Hydroporinae) with an analysis of their phyletic relationships. The Canadian Entomologist 122: 985- 1035. 450 THE CANADIW EVI'OMOLOGIST MayIJune 1997 Alarie, Y., and A.N. Nilsson. 1996. The larvae of Neonectes J. Balfour-Browne (Coleoptera: Dytiscidae: Hydroporinae) with a description of N. natrix (Sharp) and a discussion of its phylogenetic relationships with members of the tribe Hydroporini Sharp. The Coleopterists Bulletin 50: 107- 121. -1997. Larvae of Stictonectes (Brink): Generic characteristics,description of S. canariensis Machado, and analysis of relationships with other members of the tribe Hydroporini (Coleoptera: Dytiscidae). The Coleopterists Bulletin. In press. Alarie, Y., L.-J. Wang, and P.-S. Yang. 1996. The description of the larvae of Neonectes babai Sat6 (Coleoptera; Dytiscidae: Hydroporinae) with a discussion of its phylogenetic relationships with members of the Oreodytes scitulus species-group. The Coleopterists Bulletin 50: 373 - 38 1. Ax, P. 1987. The Phylogenetic System. The Systematization of Organisms on the Basis of their Phylogenesis.John Wiley & Sons, New York, NY. 340 pp. Barman, E.H., Jr. 1972. The Biology and Immature Stages of Selected Species of Dytiscidae (Coleoptera) of Central New York State. Ph.D. thesis, Cornell University, Ithaca, NY. 207 pp. Bertrand, H. 1972. Larves et Nymphes des ColCopthes Aquatiques du Globe. F. Paillart, France. 804 pp. De Marzo, L. 1977. Morfologia dei be stadi larvali di Oreodytes rivalis Gyll. e Hyphydrus aubei Ganglb. e considerazioni sul comportamento di alcuni caratteri esoscheletrici nelle larve della subf. Hydroporinae. Entomologia (Bari) 13: 85 - 119. Eldredge, N., and J. Cracraft. 1980. Phylogenetic Patterns and the Evolutionary Process. Method and Theory in Comparative Biology. Columbia University Press, New York, NY. 349 pp. Fall, H.C. 1923. A revision of the North American species of Hydroporus and Agoporus. Privately printed. 129 pp. Forey, P.L., C.J. Humphries, I.L. Kitching, R.W. Scotland, D.J. Siebert, and D.M. Williams. 1994. Cladistics. A Practical Course in Systemetics. The Systematic Association Publication 10: 191 pp. Oxford Science Publications, Oxford. Guignot, F. 1945. GCnotypes des Dytiscoidea et des Gyrinoidea. Revuefron~aised'Entomologie 13: 112- 118. Hatch, M.H. 1953. The Beetles of Pacific Northwest. University of Washington Publications in Biology 16: 340 pp. University of Washington Press, Seattle, WA. Larson, D.J. 1990. Oreodytes obesus (LeConte) and 0.sanmarkii (C.R. Sahlberg) (Coleoptera:Dytiscidae) in North America. The Coleopterists Bulletin 44: 295-303. Leech, H.B., and H.P. Chandler. 1956. Aquatic Coleoptera. pp. 293-371 in Usinger, R.L. (Ed.), Aquatic Insects of California. University of California Press, Berkeley, CA. 508 pp. Maddison, W.P., and D.R. Maddison. 1992. MacClade. Analysis of Phylogeny and Character Evolution. Sinauer Associates, Inc., Sunderland, MA. 398 pp. Matheson, R. 1914. Life-history of adytiscid beetle (Hydroporus septentrionalis Gyll.). The Canadian Entomologist 46: 37-40. Matta, J.F. 1983. Description of the larvae of Uvarus granarius with a key to the Nearctic larvae. The Coleopterists Bulletin 37: 203-207. Nilsson, A.N. 1982. A key to the larvae of the Fennoscandian Dytiscidae (Coleoptera).Fauna Norrlandica 5: 1-45. -1987a. The third-instar larvae of 8 Fennoscandian species of Hydroporus Clairville (Coleoptera: Dytiscidae) with notes on subgeneric classification.Entomologica Scandinavica 17: 491 -502. -1987b. Larval morphology of Fennoscandian Oreodytes Seidlizt (Coleoptera: Dytiscidae). Entomologisk Tidskrift 108: 99- 108. -1988. A review of primary setae and pores on legs of larval Dytiscidae (Coleoptera).Canadian Journal of Zoology 66: 2283-2294. Nilsson, A.N., and R.B. Angus. 1992. A reclassificationof the Deronectes-group of genera (Coleoptera: Dytiscidae) based on a phylogenetic study. Entomologica Scandinavica 23: 275-288. Nilsson, A.N., R.E. Roughley, and M. Brancucci. 1989. Review of the genus- and family-groupnames of the family Dytiscidae Leach (Coleoptera).Entomologica Scandinavica 20: 287-3 16. Noonan, G.R. 1992. Biogeographic Patterns of the Montane Carabidae of North America North of Mexico (Coleoptera: Carabidae). pp. 1-42 in Noonan, G.R., G.E. Ball, and N.E. Stork (Eds.), The Biogeography of Ground Beetles of Mountains and Islands. Intercept Ltd., Andover, Hampshire, UK. 256 pp. Pedelzani, F. 1995. Keys to identificationof the genera and subgenera of adult Dytiscidae (sensu lato) of the world (Coleoptera: Dytiscidae).Atti dell'Accademia Roveretana degli Agiati, a 244, ser. vii. 4: 5-83. Quicke, D.L.J. 1993. Principles and Techniques of Contemporary Taxonomy. Blackie Academic & Professional, New York, NY. 31 1 pp. Ross, H.H. 1974. Biological Systematics. Addison-Wesley Publishing Company, Inc., Reading, MA. 345 pp. Watrous, L.E., and Q.D. Wheeler. 1981. The out-group comparison method of character analysis. Systematic Zoology 30: 1- 11. Wiley, E.O. 1981. Phylogenetics. The Principles and Practice of Phylogenetic Systematics. John Wiley & Sons, New York, NY. 439 pp. Wiley, E.O., D. Siegle-Causey,D.R. Brooks, and V.A. Funk. 1991. The Compleat Cladist. A Primer of Phylogenetic Procedures. The University of Kansas Museum of Natural History, Special Publication 19: 158 pp. Williamson, D.I. 1992. Larvae and Evolution. Toward a New Zoology. Chapman & Hall, London. 223 pp. Volume 129 THE CANADIAN ENTOMOLOGIST 45 1 Wolfe, G.W. 1985. A phylogenetic analysis of pleisiotypic hydroporine lineages with an emphasis on Laccornis Des Gozis (Coleoptera: Dytiscidae). Proceedings of the Academy of Natural Sciences of Philadelphia 137: 132-155. -1989. A phylogenetic investigation of Hydrovatus, Methlini, and other plesiotypic Hydroporines (Coleoptera: Dytiscidae). Psyche (1988) 95: 327-344. Zimmerman, J.R. 1985. A revision of the genus Oreodytes in North America (Coleoptera: Dytiscidae). Proceedings of the Academy of Natural Sciences of Philadelphia 137: 99-127. (Date received: 19 April 1996; date accepted: 23 July 1996) 452 THE CANADIAN ENTOMOLOGIST MayIJune 1997 TABLE1. List of species of Oreodytes Seidlitz for which larvae were studied. The species code and larval instars are indicated

Species Code Larval instars

0.abbreviatus (Fall) ABB I1 111 0.alaskanus (Fall) ALA II 111 0.alpinus (Paykull)** ALP I I1 1n 0.angustior (Hatch) ANG I1 0.congruus (LeConte) CON 1 111 0.crassulus (Fall) CRA I 111 0.laevis (Fall) LAE I I1 111 0.obesus (LeConte) OBE I I1 111 0,picturatus (Horn) PIC I I1 111 0,productotruncatus (Hatch) PRO T 11 111 0.quadrimaculatus (Horn) QUA I I1 111 0.recticollis (Fall) REC I 111 0.sanmarkii (Sahlberg)* SAN 1 I1 m 0.scitulus (LeConte) SCI 1 I1 m 0.septentrionalis (Gyllenhal)** SEP I I1 111 0.sierrae Zimmerman SIE I I1 111 0. snoqualmie (Hatch) SNO J I1 111 0,subrotundus (Fall) SUB I 11 111

* Holarctic species; ** Palearctic; all other species Nearctic. TABLE2. Number of semndarysetae on the legs of the second-instar larvaeof selectcd species of Orerxlytes Seidlirz (species names coded as in Tahle 1): segments of legs: CO = coxa, FE = femur, TA= tarsus. 'I? = tibia. TR = trochanter; range = total number of secondary aetaeon segment: sensillar series: A = uterior. AD = anterorlorsal. AV = anteroventral, D = dorsal. PD= posterodorsail Pr = proximal, PV = posteroventral, V = ventral: rr = number of specimens studied: n.a. =nlissing dala because nf injured specimens

Species LAE SCI SNO REC PRO ALA PIC ANG QUA Segment Sensillar series (n= 5) (n= 8) (n= 4) (n= 2) (n= 2) (n= 5) (n= 4) (n= 1) (n=1)

PmCO D 3-4 2-3 3 n.a. 5-7 4-5 2-3 2 4 1 A 0-2 0 0 n.a. 3 -4 1-3 0 0 0 g V 2-4 1-4 2-3 n.a. 2-3 3-7 1-2 1 1-3 g Range 6-9 3-6 5-6 n.a. 10-14 9-15 3-5 3 5-7

AV 0 4-6 2-5 4-6 3-4 3 2-5 2-4 3-4 7-8 8 PV 4-5 2-5 3-6 3-4 3-5 3-5 3-5 2-3 5 Range 9-13 8-12 9-13 9-10 8-11 9-12 7-9 7-9 16

P~oTI AD 1-2 0- 1 0- 1 1 I 1 0- 1 0 0- 1 AV 1-2 0 1 1-2 1 1 0 0 1 PD 1 1-2 1 1 I 1 1 1 1-2 PV 1 1 1 1 0- 1 1 1 1 2 Range 4-6 2-3 3-4 4-5 3-4 4 2-3 2 5

(continued) + VIW Table 2 (continuation)

ROTA AD AV PD PV Range

MesoCO D A v Range

MesoFE AD AV PV Range

MesoTI AD AV PD PV Range

MesoTA AD AV 1-2 3 4a $ (continued) 5, 4w Table 2 (continuation)

PD PV Range

MetaCO D A v Range

MetaTR F'r

MetaFE AD AV PV Range

MetaTI AD AV PD PV Range

MetaTA AD AV PD PV Range 456 THE CANADIAN ENTOMOLOGIST MayIJune 1997 TABLE3. Number of secondary setae on the legs of the second-instar larvae of selected species of Oreodytes Seidlitz (species names coded as in Table 1); segments of legs: CO = coxa, FE = femur, TA = tarsus, TI = tibia, TR = trochanter; range = total number of secondary setae on segment; sensillar series: A = anterior, AD = anterodorsal, AV = anteroventral, D = dorsal, PD = posterodorsal, Pr = proximal, PV = posteroventral, V = ventral, n = number of specimens studied

Species

Sensillar SIE SUB SAN ABB OBE Segment series (n = 4) (n = 1) (n = 1) (n = 1) (n = 4)

ProCO D 5 3 4 2-4 3-5

V 3-5 6 1-2 6 3 Range 9-10 12-13 7-8 8- 10 6-10

ProTR Pr 1 1 1 1 1

Prom AD 2-3 3 -4 3-6 5 2-4 AV 3-4 4 3-4 5 3-5 PV 4-5 4-5 3-4 4 2-5 Range 9-11 11-13 10 14 8-12

ProTl AD 0 0 0 0 0 AV 0 0 0 0 0 PD 1 1 1 1 1 PV 1 1-2 1 1 1 Range 2 2-3 2 2 2

ProTA Range 0 0 0 0 0

MesoCO D 2-4 2-3 2-3 2-3 2-3 A 1-2 2 1-2 2-3 0- 1 V 3-5 5 1-3 4 2-4 Range 6-11 9- 10 4-8 8-10 5-8

MesoTR Pr 1 1 1 1 1

MesoFE AD 3-5 3 4-6 5 2-4 AV 4-6 5 5 6 4-6 PV 4-6 5-6 4 4-6 3-6 Range 13-15 13-14 13-15 15-17 9-16

MesoTI AD 0- 1 1 0 0 0- 1 AV 0-2 2-3 0- 1 0 1-2 PD 1 1 1 1 1 PV 0- 1 0 1 1 0 Range 3-4 4-5 2-3 2 2-4 Volume 129 THE CANADIAN ENTOMOLOGIST 457

MesoTA Range 0 0 0 0 0

MetaCO D 2-3 2 1 2 2-3 A 2 1-3 1-2 1 0-2 V 4 5-6 2 3-5 2-4 Range 8 8-11 4-5 6-8 5-8

MetaTR Pr 1 1 1 1 1

MetaFE AD 3-6 4-6 4-6 5-6 4-5 AV 5-6 7 6-7 6-8 5-7 PV 6-7 6-7 5-6 6-7 4-6 Range 15-19 18-19 16-18 18-20 14- 17

MetaTI AD 1-2 3 1-2 1-2 0-2 AV 1-3 2-3 2 1-2 1-3 PD 1-3 1 1 1 1 PV 0- 1 0-2 0 0 0 Range 5-8 7-8 4-5 4 2-6

MetaTA AD 0 0 0 0 0 AV 0 0 0 0 0 PD 0 1 0 0 0 PV 0 0 0 0 0 Range 0 1 0 0 0 TABLE^.Number of secondary set% on the legs of the third-instar larvae of selected species of Oreodytes Seidlitz (species namescoded as in Table 1); segments of legs: CO = coxa, FE = femur, TA= tarsus, TI = tibia, TR = trochanter. range = lots1 number of secondary setae on segment; sensillar series: A= anterior. AD = anterodorsal, AV = anteroventral, D =dorsal. PD = posterodorsal. Pr = proximal. PV= postemventral, V = ventral; n = number of specimens studied

Species Sensillar LAE SCI SNO REC PRO ALA PIC QUA Segment series (n = 5) (n= 12) (n = 4) (n = 2) (n = 4) (n = 5) (n = 4) (n = 5) Roc0 D A v Range

ProTR

ProFE AD AV PV Range

AD AV PD PV Range S 3.LI (continued) 3+ w S Table 4. (continuafion) + ROTA AD 0 wN AV 0-2 PD 2 PV 2 Range 4-6

MesoCO D 3-6 A 4-5 v 4-8 Range 12-17 $ 0 2-3 F AD 11-14 g AV 18-20 I PV 14-15 5 Range 43-48 S

V12 AD 5-7 AV 3-6 PD 1 PV 3 -4 Range 14-16

MesoTA 0- 1 1-3 2-3

(continued) 5 w Table 4. (continuation)

PV 1 0 0- 1 0-2 0 0 0 2-4 Range 3 -4 0 3 1-2 0 0 0 5-10

MetaCO D 3-6 3-6 3-5 3-5 5-6 4-8 2-4 3-6 A 4-7 3-5 2-4 2-4 5-8 4-6 3-4 4-5 V 3-9 2-6 4-6 3-4 5-6 6-11 3-6 6-10 Range 12-19 8- 15 10- 13 9-13 16-20 16-22 9- 12 15-19

MetaTR

MetaFE AD 6-9 5-11 8-9 5-6 6-7 6-7 7-10 13-19 02 AV 7-10 6- 12 8-9 5-7 5-8 7-8 6-9 19-23 : PV 8-10 6- 10 10-11 5-8 8-11 7-8 7-9 14-17 E Range 24-27 18-28 27 28 17-19 21-25 21-23 23-26 47-59 % - 9 4 MetaTI AD 3-6 4-7 4-6 3 3-5 3-6 3-4 7-10 9? AV 2-4 2-3 3-4 3 3-4 3-5 1-3 4-7 ,.* PD 1-3 1-3 1-3 1 1-3 1-2 1 3-4 3& PV 2-4 1-3 2-4 2-4 2-4 3-4 1-2 4-7 Range 11-15 9-13 12-16 9-11 9-15 10- 15 7-10 19-24

MetaTA AD 0 0 1-2 0 0 0 0 0- 1 AV 0 0 1 1-2 0 0- 1 0 2-6 PD 2-3 0 1-4 0 0 0 0 3-5 PV 1-2 0 0-1 0- 1 0 0 0 1-3 Range 3-6 0 4-6 1-2 0 0- 1 0 8-13 YL5 2 W oC TABLE5. Number of secondary setae on the legs of the third-instar larvae of selected species ofOrmdytes Seidlitz (species names cded as in Table 1);segments of legs: CO = coxa, E FE =femur, TA = tarsus, TI = tibia, TR = trochanter: range = total number of secondary setae on segment; sensillar series: A= anterior, AD= anterodorsal, AV = anteroventral, +2 D = dorsal, PD = posterdorsal. Pr = proximal, PV = postaroventral, V = ventral; n =number of specimens studied Nw

Species Sensillar SIE SUB SAN CON ABB CR A OBE Segment series (n = 4) (n= 1) (n = 2) (n = 3) (n = 1) (n = 3) (n = 8) ProCO D 6-8 4-6 6-8 3-9 4-5 4-7 4-7 A 1-2 2-3 1-2 0-5 1-3 0- 1 1-5 V 6-9 10-12 1-3 1-4 7-8 1-4 2-7 Range 13-19 17-20 8-12 5-17 13-15 5-11 9-15

AD 5-7 6 5-6 3-5 7 3-4 2-5 AV 5-7 7-8 4 3-5 7-8 3-5 2-5 P 7 3-4 3-8 5-6 3-5 2-4 PV 5-7 E Range 16-19 20-21 12- 14 10-18 19-21 10-13 7-13 3 AD 0 0 0 0 0 0 0 AV 0 1 0 0 0- 1 0 0 g PD 1 1 1 1 1 PV 1 1 0- 1 1 0- 1 01 1 8 Range 2 3 1-2 2 2 1 2

ProTA Range 0 0 0 0 0 0 0

MesoCO D 5-7 4-5 4-7 3-9 4 4-5 4-6 A 1-2 1 1-2 0-4 2 0-4 1-5 V 6-8 11-15 1-3 1-3 7-9 3-4 2-8 Range 12-16 16-21 7-9 4-15 13-15 9- 12 8-16

MesoTR Pr 1 1 1-2 1 1 1 1

(continued) 5 t- m t-W+ 3N m wmdz N Wt-t-- NN d I I I 30 l 00000 AILA A&Ai Al"01 0 N m TABLE6. Measurements and ratios for populations of first- and second-instar larvae of Oreodytes scitulus(LeConte) and 0. septentrionalis (Gyllenhal); n = number of specimens studied; SCI = 0.scitulus; SEP= 0.septentrionalis

First-instar larva Second-instar larva SCI SEP SCI SEP Quebec California Sweden QuCbec California Sweden Features (n=5) (n= 4) (n= I) (n= 4) (n= 5) (n= I) la (mm) 0.55-0.56 0.55-0.59 0.53 0.77-0.78 0.83-0.84 0.77 HW (mm) 0.52-0.55 0.52-0.55 0.5 1 0.70-0.76 0.78-0.79 0.71 LLAS (mm) 0.1&0.17 0.15-0.16 0.18 0.24-0.27 0.24-0.25 0.30 URO 1 length (mm) 0.64-0.68 0.74-0.81 0.64 0.92-1.01 1.09-1.16 0.95 Urn1 +Um2' length (mm) 0.99-1.01 1.07-1.11 0.95 1.39-1.47 1.59-1.54 1.41 Urogumphuslength (mm) 1.02-1.11 1.16-1.20 1.02 1.47-1.52 1.66-1.72 1.49 HWW 1.02-1.06 1.07-1.11 1.04 1.01-1.10 1.05-1.08 1.08 A2 JenghlA3 length 0.80-0.85 0.89-0.97 0.70 0.93 -1.00 1.04-1.14 0.88 A3' len_ethlA4length 0.33-0.51 0.42-0.49 0.34 0.38-0.41 0.40-0.41 0.24 FCWFCW 1.91-2.08 1.93-2.00 2.03 2.09-2.13 1.99-2.12 2.31 HW/OCW 1.68-1.79 1.88-1.98 1.77 1.65-1.99 1.76-1.78 1.89 UrolIengtNHW 1.20-1.29 1.41 -1.47 1.26 1.21-1.37 1.39-1.43 1.33 [Uml+ UroZl IengthlHW 1.80-1.91 1.95-2.21 1.86 1.82-2.03 2.04-2.08 1.98 [Uml+ U1~2]len~tb/HW 1.96-2.09 2.09-2.25 2.00 2.01-2.10 2.12-2.17 2.08 Urol length/Um2 length 1.43-1.76 1.74-2.10 1.70 1.89-1.96 1.82-1.95 1.78 Urn1 lengthRlro2' length 1.83-2.21 2.21 -2.72 2.11 1.98-2.16 2.07-2.35 2.06 TABLE7. Measurements and ratios for populations of third-instar lar~aeof Oreodytes scitulus (LeConte) and 0. septentrionalis (Gyllenhal); n = number of specimens studied; SCI = 0.scitulus; SEP = 0. septentrionalis; n.a. =missing value

SCI SEP British Columbia Features Quebec (n = 5) (n= 1) Washington (n = 2) California (n = 4) Sweden (n = 2)

HL (nun) 1.01-1.07 1.16 1.01-1.03 1.13-1.17 0.97 HW(mm) 0.99-1.03 1.08 0.99-1.00 1.08-1.11 0.85 -0.86 LLAS(mm) 0.36-0.39 0.38 0.37 0.38-0.39 0.36 -0.38 UROl length (mm) 1.22-1.43 1.69 1.23-1.24 1.36- 1.48 1.31-1.35 Llrol +Uro2' length (mm) 1.82-2.20 2.58 1.97-1.98 2.15-2.30 1.99-2.07 Umgumphuslength (mm) 1.84-2.22 2.61 2.03 2.21 -2.25 2.04-2.13 HL/Hw 0.97- 1.08 1.07 1.01-1.04 1.03-1.08 1.13-1.14 A2 lenpthIA3 length 0.98-1.16 1.24 1.16-1.23 1.19-1.24 1.00-1.13 A3' lenp~hIA4length 0.41-0.52 0.56 0.44-0.52 0.43-0.51 0.32-0.36 FCWFCW 1.99-2.13 2.16 2.13-2.20 1.91-2.07 2.24 HWJOcW 1.44-1.56 1.56 1.55-1.61 1.49-1.60 1.70-1.85 Urn1 length/HW 1.X-1.39 1.57 1.24 1.23-1.33 1.52-1.58 [Urot +Uro2']length/HW 1.84-2.13 2.4 1.97-2.00 1.96-2.09 2.31-2.43 I Uro I+Uro2] lengthm 1.86-2.08 2.42 n.a. 2.00-2.09 2.37-2.50 Urn1 lengthlllro2,length 1.96-1.98 1.85 n.a. 1.60-1.84 1.72- 1.78 Urn1 lengthKJrn2'length 1.85-2.18 1.91 1.64-1.69 1.71-1.85 1.86-1.91 volume 129 THE CANADIAN ENTOMOLOGIST 465

wumZ m IIII I mmm-- N

u mmm- N IIII I wNm2 3

u mw,- IIII mmmm 3

muum IIII h(NNW Table 8. (continuation)

MesoFE AD 3-4 3-4 3-6 5-9 6-7 5-6 5-7 AV 4-6 5-7 3-5 5-7 4-8 4-6 4-6 PV 4-5 5 5-6 6-8 6-8 7-8 6-8 Range 12-13 14-15 11-17 17-24 16-22 18 16-20

MesoTI AD AV PD PV Range

MesoTA Range

MetaCO D A v Range

MetaTR

MetaFE AD 5-6 5-6 5-8 6-11 6-8 6-7 5-9 AV 4-5 5-6 4-7 6-8 7- 12 7-8 6-9 PV 4-7 6 5-7 7-8 8-10 8 6-9 Range 15-16 16-18 14-22 20-26 21-28 21-23 18-25

AD 2-3 1-2 3-4 5-7 4-5 5-7 5-7 AV 2 1-2 1-2 2-3 2-3 3 2-3 PD 2-3 2 1-2 2 1 1-2 1-3 PV 1-2 0-2 1-2 1-3 1-2 1 1-2 Range 8-9 6 7-10 11-13 9-10 10-13 10-13 Y, MetaTA Range 0 0 0 0 0 0 0 B w 4wrg TABLE9. Selected measurements and ratios for larvae of Oreodytes laevis (Fall) and 0, alpinus (Paykull): n = number of specimens studied; LAE = 0. laevis: ALP = 0. alpinus

LAE lnstar 1 ALP Instar 1 LAE Instar 2 ALP Instar 2 LAE Instar 3 ALP Instar 3 Features (n = 6) (n = 1) (n = 5) (n= 1) (n = 5) (n= 1)

HL (mm) 0.55-0.61 0.59 0.79-0.85 0.83 1.07-1.21 1.18 HW (mm) 0.47-0.57 0.58 0.73-0.81 0.75 0.95-1.13 1.10 US(mml 0.17-0.19 0.22 0.28-0.33 0.31 0.46-0.52 0.5 1 UROl length(mm) 0.78-0.88 0.84 1.18-1.33 1.17 1.72-2.02 1.76 Uro1+UN~' length (mm) 1.09-1.24 1.16 1.67-1.89 1.76 2.46-2.75 2.53 Urogumphus length (mm) 1.18-1.34 1.25 1.78-1.95 1.83 2.50-2.81 2.58 ku-4'I-m 1.04-1.17 1.01 1.02-1.11 1.11 1.01-1.17 1.07 A2 lengthlk' length 0.83-0.94 0.86 0.84- 1.03 0.99 1.03-1.19 1.17 A3' length/A4length 0.26-0.32 0.30 0.27-0.33 0.30 0.34-0.43 0.33 FmCW 2.15-2.36 2.19 2.24-2.45 2.54 2.19-2.48 2.59 UWJOcW 1.50-1.64 1.65 1.47-1.63 1.62 1.41-1.60 1.63 Urol IengWHW 1.50-1.68 1.43 1.54-1.75 1.60 1.63-1.93 1.60 [Urn l+Um2~lcngth/HW 1.98-2.34 1.99 2.22-2.42 2.34 2.32-2.81 2.30 ~rol+Um2llength/FIW 2.22-2.55 2.15 2.29-2.49 2.44 2.35-2.86 2.35

UrnL lengthRTro2 length 1.91-2.22 2.01 2.05-2.36 1.78 2.08-2.59 2.16 Urn 1 length/Uro2' len$h 2.29-2.87 2.59 1.98-2.60 2.01 2.18-2.76 2.28 TABLE10. Measurements and ratiosfor selected population samplesof Oreodytes obesus (LeConte); n = number of specimens studied;n.a. = missing value

First-instar Second-instar Third-instar

Yukon Oregon California Alberta Oregon Washington Oregon California Features (n = 3) (n = 3) (n = 3) (n= 1) (n = 3) (n = 3) (n= 1) (n = 4)

HL (mm HW (mm) LLAS (mm) UROl length (mm) Urn I+Um2' length (mm) Urogumphuslength (mm) HUHW M lengrh/A3 length A3' lengthlA4 length FC4FCW HW/OcW Uml 1engthRlW vrol+Uro2'] length/HW [UroL+Uro2j lengthm

Urn 1 lengthltTm2length Urn l lengthlllro2' length Volume 129 THE CANADIAN ENTOMOLOGIST 469

TABLE11. Number of secondary setae on the legs of the second- and third-instar larvae of selected populations of Oreodytes obesus (LeConte); segments of legs: CO = coxa, FE = femur, TA = tarsus, TI = tibia, TR = trochanter; range = total number of secondary setae on segment; sensillar series: A = anterior, AD = anterodorsal, AV = anteroventral, D = dorsal, PD = posterodorsal, PI = proximal, PV = posteroventral, V = ventral; n =number of specimens studied; localities: Alb. = Alberta, Calf. = California, Ore. = Oregon, Wash. =Washington

Localities Ore. Alb. Calf. Wash. Ore. (n = 3) (n = 1) (n = 4) (n = 3) (n = 1) Sensillar Segment series ProCO D A v Range

ProTR

ProFE AD AV PV Range

AD AV PD PV Range

ProTA Range

MesoCO D A v Range

Pr AD AV PV Range

MesoTI AD AV PD PV Range

Range

D A v Range (continued) 7HE CANADIAN ENTOMOLOGIST Table 11. (continuation)

MetaFE AD AV PV Range

AD AV PD PV Range

MetaTA Range

TABLE12. List of the species of Hydroporinae other than Oreodytes Seidlitz studied in the phylogenetic analysis

Hydroporini Heterosternuta cocheconis Fall Heterosternuta wickhami Zaitsev Hydroporus badiellus Fall Hydroporus columbianus Fall Hydroporus dentellus Fall Hydroporus fuscipennis Schaum * Hydroporus morio AubC * Hydroporus nigellus Mannerheim * Hydroporus niger Say Hydroporus obscurus Sturm * Hydroporus puberulus LeConte * Hydroporus signatus Mannerheim Hydroporus striola Gyllenhal * Hydroporus tenebrosus LeConte Hydroporus tristis (Paykull) * Hydroporus (oblitus)paugus Fall Neoporus carolinus (Fall) Neoporus solitarius (Sharp) Neoporus tennetum (Wolfe) Neoporus undulatus (Say) Hygrotus dissimilis Gemminger and Harold Hygrotus falli (Wallis) Hygrotus farctus (LeConte) Hygrotus hudsonicus Fall Hygrotus impressopunctatus (Scaller) * Hygrotus laccophilinus LeConte Hygrotus masculinus (Crotch) Hygrotus patruelis (LeConte) Hygrotus picatus Kirby Hygrotus sayi Balfour-Browne Hygrotus tumidiventris (Fall) Nebrioporus rotundatus (LeConte) Sanfilippodytes planiusculus (Fall) Stictotarsus griseostriatus (De Geer) * Laccomini Laccornis conoideus (LeConte) Laccornis latens (Fall) + Nw TABLE 13. Character matrix of 29 morphological characters of larvae of selected species of OmdyterSeidlitz. The 29 columns correspond to the character numbers given in the text; 0 indicates plesiomorphic stateand numbers greater than 0 indicate progressively more apomorphic states; '=arose independently from 0; ? =missing data (species names coded as in Table 1)

Transformation series 00000000011111111112222222222 Species Species-group names12345678901234567890123456789

quadrimaculatus QUA picturatus PIC ANG scitulus SCI SNO LAE REC PRO ALA OBE CON SAN CRA ABB SIE SUB THE CANMIM EN'IOMOLOG~ST

ocw

FIGS.1, 2. Oreodytespicturatus (Horn), cephalic capsule, first-instar larva: 1, dorsal aspect; 2, ventral aspect. EB = egg-bursters; FCW = width of frontoclypeus; FR = frontoclypeus; LC = lamellae clypeales; OcW = occipital foramen width; PA = parietale; TP = tentorial pits; numbers and lowercase letters refer to primary setae and pores, respectively. Scale bar = 0.10 mm. Volume 129 THE CANADIAN E.hlDMOLOGIST

FIGS. 3-5. Distribution of ancestral setae and pores of a generalized larva of Oreodytes Seidlitz: 3, left antenna (ventral aspect); 4, left antenna (dorsal aspect); 5,mandible (dorsal aspect). AN = antenna; MN= mandible; numbers and lowercase letters refer to primary setae and pores, respectively; Sp = spinula. Scale bar = 0.10 mm. THE CANADIAN ENTOMOLOGIST

FIGS.6-9. Distribution of ancestral setae and pores of a generalized larva of Oreodytes Seidlitz: 6, left maxilla (dorsal aspect); 7, left maxilla (ventral aspect); 8, labium (ventral aspect); 9, labium (dorsal aspect). LA = labium; MX = maxilla; numbers and lowercase letters refer to primary setae and pores, respectively. Scale bar = 0.10 mm.

FIGS. 10, 11. Right maxilla of first-instar larva of 0.subrotundus (Fall): 10, dorsal aspect; 11, ventral aspect. add. = additional seta; numbers and lowercase letters refer to primq setae and pores, respectively. Scale bar = 0.10 mm. Volume 129

FIGS. 12-15. Ventral aspect of right antennomeres 3 and 4 of first-instar larva of selected species of Oreodytes Seidlitz: 12,O. obesus (LeConte); 13,O. sierrae Zimmerman; 14,O. subrotundus (Fall); 15,O. crassulus (Fall). Sp. = spinula; numbers refer to primary setae. Scale bar = 0.10 mm.

FIGS. 16-20. Ventral aspect of right antennomeres 3 and 4 of fust-instar larva of selected species of Oreodytes Seidlitz: 16, 0.picturatus (Horn); 17, 0. scitulus LeConte; 18,O. recticollis (Fall); 19,O. productotruncatus (Hatch); 20,O. quadrirnaculatus (Horn). Sp. = spinula; numbers refer to primary setae. Scale bar = 0.10 mm. FIGS.21,22. Oreodytes scitulus (LeConte), dorsal aspect of cephalic capsule of first-instar larva: 21, QuCbec, Canada; 22, California, USA. Scale bar = 0.10 rnrn. Volume 129 THE WADIAN ENWMOLWIST

RGS.23,24. Dorsal aspect of cephalic capsule of first-instar larva of selected species of Oreodytes Seidlitz: 23, 0.snoqualmie (Hatch); 24, 0. laevis (Fall). Scale bar = 0.10 mm. THE CANADIAN Eh7DMOLOC;IST

FIGS.25,26. Dorsal aspect of cephalic capsule of first-instar larva of selected species of Oreodytes Seidlitz: 25, 0.productotruncatus (Hatch); 26, 0.recticollis (Fall). Scale bar = 0.10 mm. Volume 129 THE CAh'MIAN F.NTOMOUWjlST

FIGS.27,28. Dorsal aspect of cephalic capsule of first-instar larva of selected species of Oreodytes Seidlitz: 27, 0. subrotundus (Fall); 28.0. sierrae Zimmerman. Scale bar = 0.10 mm. THE CANADIAN ENTOMOLOGIST

FIGS.29,30. Oreodytes obesus (LeConte), dorsal aspect of cephalic capsule of first-instar larva: 29, California, USA; 30, Yukon Territory, Canada. Scale bar = 0.10 mm. Volume 129 THE CANADIAN ENTOMOLCGIfl

FIGS. 3 1, 32. Dorsal aspect of cephalic capsule of first-instar larva of selected species of Oreodytes Seidlitz: 3 1, 0.congruus (LeConte); 32,O. sanmrkii (Sahlberg). Scale bar = 0.10 mm. THE CANADIAN ENTOMOLOGIST

FIGS.33,34. Dorsal aspect of cephalic capsule of first-instar larva of selected species of Oreodytes Seidlitz: 33, 0.crassulus (Fall); 34, 0.quadrimaculatus (Horn). Scale bar = 0.10 mm. Volume 129 THE CANADIAN ENTOMOLOGIST

FTG. 35. Dorsal aspect of cephalic capsule of thud-instar larva of Oreodytespicturatus (Horn).Scale bar = 0.10 mm. THE CANADIAN ENTOMOLOGIST

FIGS.36,37. Oreodytes laevis (Fall), dorsal aspect of cephalic capsule of third-instar larva: 36, Washington, USA, 37, British Columbia, Canada. Scale bar = 0.10 mm. Volume 129 THE CANADIAN ENTOMOLOGIST

39 FIGS.38,39. Oreodytes scitulus (LeConte), dorsal aspect of cephalic capsule of thiid-instar larva: 38, QuBbec, Canada: 39. California. USA. Scale bar = 0.10 mm. THE CANADlAN ENTOMOLOGIST

FIGS. 40,41. Dorsal aspect of cephalic capsule of third-instar larva of selected species of Oreodytes Seidlitz: 40, 0.snoqualmie (Hatch); 41, 0.recticollis (Fall). Scale bar = 0.10 mm. Volume 129 THE CANADIAN ENTOMOLOGIST

FIGS.42,43. Dorsal aspect of cephalic capsule of third-instar larva of selected species of Oreodytes Seidlitz: 42, O.productotruncatus (Hatch); 43,O. alaskanus (Fall). Scale bar = 0.10 mm. THE CANADIAN ENTOMOLOGIST

FIGS.44,45. Dorsal aspect of cephalic capsule of third-instar larva of selected species of Oreodytes Seidlitz: 44, 0. quadrimaculatus (Horn); 45,O. abbreviatus (Fall). Scale bar = 0.10 mm. Volume 129 THE CANADIAN EWOMOLOGIST

FIGS 46,47. Dorsal aspect of cephalic capsule of third-instar larva of selected species of Oreodytes Seidlitz: 46, 0.crassulus (Fall); 47,O.sanmarkii (C.R. Sahlberg). Scale bar = 0.10 mm. THE CANADIAN ENWMOLOGIST

FIGS.48,49. Dorsal aspect of cephalic capsule of third-instar larva of selected species of Oreodytes Seidlitz: 48, 0.sierrae Zimmerrnan; 49, 0.subrotundus (Fall). Scale bar = 0.10 mm. Volume 129 THE CANADIAN EFiMMOMFIST

FIGS.50,51. Dorsal aspect of cephalic capsule of third-instar larva of selected species of Oreodytes Seidlitz: 50, 0.congruus (LeConte); 51,O. obesus (LeConte). Scale bar = 0.10 mm. THE CANADIAN ENTOMOLOGIST

TI. l1 TR , 53 CO -

FIGS.52, 53. Metathoracic legs of a generalized first-instar larva of Oreodytes Seidlitz: 52, anterior face; 53, posterior face. CO = coxa; D = dorsal; FE = femur; PD = posterodorsal, Pr = proximal; PT = pretarsus; PV = posteroventral; TA= tarsus; TI = tibia; TR = trochanter; V = ventral; numbers and lowercase letters refer to primary setae and pores, respectively. Scale bar = 0.10 mm.

FIGS.54,55. Oreodytes quadrimaculatus (Horn),metathoracic legs, third-instar larva: 54, anterior face, 55, posterior face. Sensillar series: A = anterior; AV = anteroventral; AD = anterodorsal; D = dorsal; Pr =proximal; PV = posteroventral; V = ventral. Scale bar = 0.10 mm. Volume 129 THE CANADIAN ENTOMOLOGIST

FIGS.56,57. Oreodytes laevis (Fall), metathoracic legs, third-instar larva: 56, anterior face; 57, posterior face. Scale bar = 0.10 mm.

59 FIGS.58,59. Oreodytes picturatus (Horn), metathoracic legs, third-instar larva: 58, anterior face; 59, posterior face. Scale bar = 0.10 mm. THE CANADIAN ENTOMOLOGIST

FIGS 60,61. Oreodytes sierrae Zimrne~~nan,metathoracic legs, third-instar larva: 60, anterior face; 61, posterior face. Scale bar = 0.10 mm. Volume 129 THE CANADIAN ENTOMOLOF~ST

FIGS. 62,63. Last abdominal segment of a generalized first-instar larva of Oreodytes Seidlitz: 62, dorsal aspect; 63, ventral aspect. AB = abdomen segment 8; numbers and lowercase letters refer to primary setae and pores, respectively. Scale bar = 0.10 mm.

FIGS. 64-66. Dorsal aspect of last abdominal segment of first-instar larva of selected species of Oreodytes Seidlitz: 64,O. productotruncatus (Hatch); 65,O. quadrimaculatus (Horn); 66,O. picturatus (Horn). add = additional seta; numbers and lowercase letters refer to primary setae and pores, respectively. Scale bar = 0.10 mm. THE CANADLAN ENWMOLffiIST

67

FIGS.67,68. Dorsal aspect of last abdominal segment of first-instarlarva of selected species of Oreodytes Seidlitz: 67, 0.crassulus (Fall); 68, 0.sierrae Zimmeman. add = additional seta; numbers and lowercase letters refer to primary setae and pores, respectively. Scale bar = 0.10 mm. Volume 129 THE CANADIAN EhPI'DMOLOCrIST

FIGS. 69,70.Dorsal aspect of last abdominal segment of third-instar larva of selected species of Oreodytes Seidlitz: 69,O. scitulus (LeConte); 70,O.quadrimaculatus (Horn). Scale bar = 0.10 mm. THE CANADIAK EhTOMOLffilST

FIGS.71,72. Dorsal aspect of last abdominal segment of third-instar larva of selected species of Oreodytes Seidlitz: 71,O. obesus (LeConte); 72,O.picturatus (Horn). Scale bar = 0.10 mrn. Volume 129 THE CANADIAN ENTOMOLOGIST

RGS. 73,74. Urogomphus of first-instar larva of selected species of Oreodytes Seidlitz: 73,O. snoqualmie (Hatch); 74, 0.sierrae Zimmerman. UR = urogomphus; asterisk = additional pore; numbers and lowercase letters refer to primary setae and pores, respectively. Scale bar = 0.10 mm. THE CANALNAY ENTOMOLwl.W

FIGS.75, 76. Urogornphus of first-instar larva of selected species of Oreodytes Seidlitz: 75, 0. quadrimaculatus (Horn); 76,O.picturatus (Horn). UR = urogomphus; asterisk = additional pore; numbers and lowercase letters refer to primary setae and pores, respectively. Scale bar = 0.10 rnrn. Volume 129 THE CANADIAN ENT0MOLOGI.V

FIGS. 77-79. Urogomphus of selected species of Oreodytes Seidlitz: 77,O. quodrimaculatus (Horn), third-instar larva; 78,O.picturatus (Horn), third-instar larva; 79,O. angustior (Hatch), second-instar larva. Scale bar = 0.10 mm. THE CANADIAN ENTOMOLOGIST

FIGS. 80, 81. Urogomphus of third-instar larva of selected species of Oreodytes Seidlitz: 80,O.snoqualmie (Hatch); 8 1,O. sierrae Zimmerman. Scale bar = 0.10 rnm. Volume 129 THE CANADIAN ENTOMOLOGIST

FIG.82. Tentative reconstructed phylogeny of Nearctic Oreodytes Seidlitz. Only the putative synapomorphies supporting a monophyletic origin for the genus Oreodytes have been represented (see PHYLOGENETIC ANALYSIS for details). Minus (-) =reversal from the derived condition; asterisk (*) = homoplasy; prime (') = independently evolved character state.