268 



Denning: Trichoptera 



— Base of 10th tergite without such a pair of spurs; 

 claspers with 2 or 3 processes 5 



5. Basal process of clasper very short, barely reaching 

 above clasper (fig. 10:33i); Mono, Tuolumne, and 

 Placer counties roafi (Milne) 1936 



— Basal process of clasper long, reaching considerably 

 above clasper 6 



6. Lobe of 10th tergite with apical portion long, ovate, 

 and concave; apex of claspers truncate (fig. 10:33c); 

 Marin and Plumas counties jewetti Ross 1946 



— Lobe of 10th tergite short, not of above type; claspers 

 tapering toward apex 7 



7. Clasper, lateral aspect, with apex acute 8 



— Clasper, lateral aspect, with apex fairly blunt, or 

 with a buttonlike ventral lobe 10 



8. Tenth tergite with a prominent spur along lateral 

 aspect (fig. 10:34t); Tuolumne County 



mira Denning 1 954 



— Tenth tergite with no spur along lateral aspect 9 



9. Lobes of 10th tergite with a sharp dorsal projection; 

 front legs scaled (fig. 10:33d); northern California 



podager (McLachlan) 1871 



— Lobes of 10th tergite without a dorsal projection; 

 (fig. 10:33ft) front legs not scaled; Tulare, Tuolumne, 

 El Dorado, and Madera counties 



cascadensis (Milne) 1936 



10. Tenth tergite with no dorsal projection, ventral corner 

 attenuated (fig. 10:33/); northern California 



strophis Ross 1938 



— Tenth tergite with dorsal projection, ventral corner 

 not attenuated 11 



11. Tenth tergite lobes with a short, dorsal spine, ventral 

 margin incised (fig. 10:33A); widespread 



unicolor (Banks) 1911 



— Tenth tergite lobe with prominent dorsal spine, ventral 

 lobe elongated (fig. 10:35e); Del Norte County 



astanea Denning 1954 



Family BRACHYCENTRIDAE 



Fig. 10:35. Head and genitalia of male Trichoptera. a, 

 sema aspilus, head; a 1# clasper; o 2 , genitalia, lateral; b, 

 sema onisca, lateral; b t , clasper, dorsolateral view; c, 

 plectrum echo, genitalia, lateral; d, Brachycentrus amer 

 genitalia, lateral; e, Lepidostoma astanea, genitalia, 

 (a,c, Ross, 1938; b, Ross, 1947; d, Ross, 1938; e, I 

 1954b). 



Micro- 

 Micra- 

 Oligo- 



icanus, 

 lateral 



enning, 



The family is represented in the Nearctic region by 

 three genera and twenty-eight species. All the known 

 genera but only four species have been recorded from 

 California. 



Key to the Genera 

 Adult. 21 



1. Front wings with R 4 and R, sessile, branched at r and 

 r-m; spurs not 2-2-2 Brachycentrus Curtis 1834 



— Front wings with R 4 , 5 stalked, branched beyond r-m; 

 spurs 2-2-2 2 



2. Front wings with cell 2A small, vein 2A strong 



Oligoplectrum McLachlan 1868 



— Front wings with cell 2 A large, or part or all of vein 

 2A atrophied Micrasema McLachlan 1876 



Known Larvae 



1. Middle and hind tibiae with an inner, apical spur; 

 mesonotum with sclerites long and narrow; metanotal 

 plates heavily sclerotized . . Brachycentrus Curtis 1834 



— Middle and hind tibiae without an inner spur; mesonotal 

 sclerites short, wide; metanotal plates lightly sclero- 

 tized Micrasema McLachlan 1876 



1 Adapted from Ross (1947). 



Genus Micrasema McLachlan 1876 



Fourteen Nearctic species are known, but only two 

 have been reported from California. Since most of the 

 species are western in distribution, it is probable 

 that additional species will be collected in the state. 



aspilus (Ross) 1938a (fig. 10:35a) widespread 



onisca Ross 1947 (fig. 10:35ft) Monterey, Fresno, 



Riverside, and San Diego counties 



Genus Oligoplectrum McLachlan 1868 



Only two North American species have been referred 

 to this genus and one of these has been collected in 

 California, 0. echo Ross 1947 (fig. 10:35c) (Mono 

 and Plumas counties). The larvae are unknown. 



Genus Brachycentrus Curtis 1834 



Twelve Nearctic species are known but only one is 

 recorded from California, B. americanus (Banks) 1899 

 (fig. 10:35c?) (Mono and Shasta counties). This species 

 is abundant and widely distributed. Emergence, egg 



