Fig. 10:23. Male genitalia, a, Cheumafopsyche campyla, lateral; 

 a„ tenth tergite; b, Cheumafopsyche mickeli, lateral; b„ tenth 

 tergite; c, Hydropsyche cockerelli, lateral; d, Cheumafopsyche 

 mollala, lateral; d„ tenth tergite; e, Hydropsyche californica, 

 aedeagus, ventral; e t , aedeagus, lateral; f, Hydropsyche oslari, 

 lateral; g, Hydropsyche occidentalis, aedeagus, ventral; g 1( 

 aedeagus, lateral; h, Hydropsyche philo, lateral (a, Ross, 1944, 

 b, Denning, 1942; c,e,f,g, Ross, 1938; d,h, Ross, 1941). 



253 

 Denning: Trichoptera 



— Apical segment of clasper short, stout; apical lobes 

 of 10th tergite short, acutely triangulai (fig. 10:'J 

 Del Norte County mollala Ro- 1941 



2. Lateral margin of apical lobes of 10th tergite with 

 no lateral expansion (fig. 10:23a); Siskiyou Count\ . . 

 campyla Rosa IMS 



— Lateral margin of apical lobes of 10th tergite with 

 distinct lateral expansions (fig. 10:28ft); Sierra to 

 Los Angeles counties mickeli Denning 19 12 



Genus Hydropsyche Pictet 1834 



Hydropsyche, with about fifty-five Nearctic species, 

 is the largest genus in the family. Thus far only five 

 species have been recorded from California. Locally 

 some species are very abundant. Larvae are free- 

 living and spin webs on rocks in swift-flowing 

 streams. 



Key to Adult Males 



1. Aedeagus with membranous lateral processes bearing 

 a long curved spine (fig. 10:23c); Siskiyou and Sierra 

 counties cockerelli Banks 1905 



— Aedeagus without membranous lateral processes .... 2 



2. Apical segment of clasper rather long, curved 3 



— Apical segment of clasper short, approximately quadrate 



' 4 



3. Apical segment of clasper attenuated, long, slender 

 and curved (fig. 10:23/); Trinity County to Riverside 

 County oslari Banks 1905 



— Apical segment of clasper flattened, saber-shaped 

 (fig. 10:23A); Monterey County to San Bernardino 

 County philo Ross 194 1 



4. Aedeagus, ventral aspect, with lateral margin irregular, 

 a sharp angulation along margin a short distance be- 

 fore apex (fig. 10:23e); Shasta County to Santa Clara 

 and Fresno counties californica Banks 1899 



— Aedeagus, ventral aspect, with lateral margin not 

 irregular, no angulation before apex, a triangular notch 

 along margin near apical margin (fig. 10:23^); wide- 

 spread occidentalis Banks 1900 



Family H YDROP TILIDAE 



This is the family of microcaddisflies, which gener- 

 ally average less than 6 mm. in length. The small 

 adults are very hairy and often have a dark mottled 

 appearance. They are found along ponds, large lakes, 

 or streams and often occur in abundance. 



Twelve genera and about one hundred and thirty 

 species occur in the United States and Canada, but 

 many others probably will be taken because this 

 family is usually poorly represented in collections. 

 In California only five genera and ten species are 

 recorded. 



we know of only three species in California. Generally 

 the larvae are found under the same ecological condi- 

 tions as Hydropsyche, and similarly built nets are 

 constructed which strain food from the flowing water. 



Key to the Adult Males 



1. Apical segment of clasper long, slender; apical lobes 

 of 10th tergite long, narrow (fig. 10:23a) 2 



Key to the Genera 10 

 Adult* ' 



1. Ocelli absent 2 



— Ocelli present 4 



2. Front tibiae with apical spur ....... Dibusa Ross 1939 



"Adapted from Ross (1944). 



