1948] 
Denning — Near die Trichoptera 
17 
from lateral aspect, spatulate from dorsal or ventral as- 
pect ; lateral apical lobe very irregular and bearing sev- 
eral long stout setae. Between base of claspers arise a 
pair of filamentous lobes bearing at apex two long slender 
setae. MMeagus semi-membranous with characteristic 
spoonlike ventral plate. 
Holotype. Male. — Sybille River, near Wheatland, 
Wyoming, June 19, 1947 (D. G. Denning). 
Athripsodes pfadti n. sp. 
This species is very similar to arielles Denning, but 
differs from it in details of the tenth tergite, such as the 
clusters of minute spines along the lateral surface, in the 
wide sclerotized lobe of the clasper, and the presence of 
two large internal spines in the aedeagns. 
Male. — Length 8-9 mm. Eyes small, separated on dor- 
sum by about five times the dorsal width of one eye. An- 
tennae rather short, about one and one-third times the 
length of the forewing; basal portion of each segment 
white, gradually becoming uniformly brownish. Wings 
light brown, a prominent white spot at tip of anal veins, 
a fringe of white hairs along margin, extending from R 
to Ms. Legs a lighter shade than wings. 
Genitalia as in fig. 2. Ninth segment with base wide, 
considerably narrowed toward center; articulation with 
cerci quite indistinct. Cerci, from dorsal aspect, sub- 
triangular, apices separated by a wide triangular incision, 
a few long fine setae present. Tenth tergite reaching 
caudad slightly beyond cerci, apex upturned ; viewed from 
dorsal aspect apical margin straight ; lateral surface with 
two clusters of minute spines, one nearly circular group 
of six, and one group of three. Clasper with basal por- 
tion projected caudad a short distance which appears as a 
prominant sub-triangular point when viewed from the 
caudal aspect, fig. 2A; apical segment semi-membranous, 
digitate, bearing a scattering of rather stout setae ; sclero- 
tized lobe shorter than apical segment, considerably ex- 
panded apically, margin rounded when viewed laterally ; 
somewhat hammer-shaped from caudal view, fig. 2A, a 
pair of small setae along margin ; caudal surface of basal 
