251 

 Denning: Trichoptera 



stout, short, black, scaleliko hairs arranged in tufts 

 along dorsum near sides, frequently with broad scales 

 scattered between them Parapsyche Betten 1934 



— Gula narrowed posteriorly; abdomen without distinct 

 setal tufts, with coarse hairs of varying lengths, some 

 of them scale-like but narrow and long (fig. 10:20e) 



Arctopsyche McLachlan 1868 



7. Mandibles with winglike dorsolateral flanges along 

 basal half; submentum cleft Potamyia Banks 1900 



— Mandibles without distinct dorsolateral flanges; sub- 

 mentum subconical, not cleft 8 



8. Frons expanded laterad, its lateral extensions sharp 



Diplectrona Westwood 1840 



— Frons not expanded laterad, its lateral extensions 

 scarcely produced Smicridea McLachlan 1871 



Fig. 10:20. Larval structures of Hydropsychidae. a, Hydrop- 

 syche, mandibles; b, Cheumatopsyche, mandibles; c, Hydropsyche 

 cheilonis, larval stridulator of front leg; d, Smicridea fasciatella, 

 larval stridulator of front leg; e, Arctopsyche, head of larva, ven- 

 tral; f, Diplectrona; head of larva, ventral (Ross, 1944). 



8. Front and hind wings similar in shape and size, broad 

 and short 9 



— Front and hind wings considerably different, hind wing 

 margin arcuate 10 



9. Apical margin of both wings incised 



Oropsyche Ross 1941 



— Apical margin of both wings evenly rounded 



Aphropsyche Ross 1941 



10. Base of aedeagus cylindrical; cell Rj of hind wings 

 present Hydropsyche Pictet 1834 



— Base of aedeagus bulbous; cell R a of hind wings 

 absent Cheumatopsyche Wallengren 1891 



Koy to the Known Larvae 9 



1. Head with a broad, flat dorsal area set off by an ex- 

 tensive arcuate carina. . . .Macronemum Burmeister 1839 



— Head without a dorsal area set off by a carina 2 



2. Left mandible with a high thumblike, dorsolateral 

 projection Genus A 



— Left mandible without a dorsolateral projection, at 

 most with a carina 3 



3. Stridulator of front leg forked (fig. 10:20c) 4 



— Stridulator of front leg not forked (fig. 10:20<f) 5 



4. Prosternal plate without a pair of sclerites posterior 

 basal tooth of mandibles single (fig. 10:20a) 



Hydropsyche Pictet 1834 



— Prosterna'l plate without a pair of sclerites posterior 

 to it; basal tooth of mandibles double (fig. 10:206) 



Cheumatopsyche Wallengren 1891 



5. Gula rectangular and long (fig. 10:20e), separating 

 genae completely; each branched gill with all its 

 branches arising at top of basal stalk 6 



— Gula triangular and short (fig. 19:20/), genae therefore 

 fused for most of their length; each branched gill with 

 branches arising from both sides and top of basal 

 stalk 7 



6. Gula rectangular and of even width; abdomen with 



Slightly modified from Ross (1944). 



Genus Arctopsyche McLachlan 1868 



This is a small genus containing five Nearctic spe- 

 cies. Three species are western and two are found in 

 eastern Canada and United States. The species are 

 large and generally dark grayish. 



Key to Adult Moles 



1. Tenth tergite with a pair of long slender prongs 2 



— Tenth tergite with a pair of short dorsal and ventral 

 prongs (fig. 10:2 lo); Shasta County 



calif omica Ling 1938 



2. Prongs of 10th tergite convergent, sharply acuminate 

 in lateral aspect (fig. 10:21 rf); Santa Catalina Mts. 



inermis Banks 1943 



— Prongs of 10th tergite not especially convergent, 

 generally wide throughout except extreme tip (fig. 



10:2 lb); Trinity County to El Dorado County 



grandis (Banks) 1900 



Genus Diplectrona Westwood 1840 



This is a small genus represented by only three 

 species, two eastern and one, D. californica Banks 

 1914, from California. The latter was originally 

 described from a specimen collected at Claremont, 

 Los Angeles County, and at present cannot be 

 identified. 



Genus Homoplectra Ross 1938 



The genus is represented by five western species. 

 All species except H. alseae Ross (from Oregon) 

 have been found in California. 



Key to Adult Males 



1. Armature of the aedeagus with a short, dorsal spine 

 arising at the base of the structure, the spine not much 

 more than half as long as rest of structure (fig. 10:21 e) 

 2 



— Armature of aedeagus with a long, slender, dorsal 

 spine, which is nearly as long as rest of structure 

 (fig. 10:2U) 4 



2. Dorsal spine at base of aedeagus curved dorsad, 

 reaching considerably above rest of structure (fig. 

 10:21c); Marin County nigripennis (Banks) 1911 



