Vorhies—Studies on the Trichoptera of Wisconsin. 713 
into the sand. The great size of the discharging surface, the 
posterior membrane, may be due to this fact. One of these lar¬ 
vae lived for some time in a dish in the laboratory, where it 
burrowed in the sand supplied for it and rapidly constructed 
an elaborately branched case, which then was easily exposed by 
washing away the sand with a gentle stream of water. 
A case similar to this is described and figured by Miss Clarke 
(1891) but ascribed to the larva of Plectrocnemia. That it be¬ 
longs to this genus, however, there can be little doubt, as she 
mentions the long “spinneret” of the larva. 
Habits and Occurrence. —Beyond what observations on habits 
it seems necessary to include with the account of the case, I 
have nothing to give. I have taken the larvae and pupae only 
in the stream at Devil’s Lake (both on June 29) and the imagos 
were reared from these. The other two species of the genus 
measure only 13 and 14 mm. in wing expanse, hence the name 
given to this one. 
(PI, LIII, Fig. 8. PI. LXI, Figs. 1-13.) 
RHYACOPHILIDiE 
Rliyacophila torva Hagen. 
Rhyacophila torva Hagen, Syn. Heur. H. Am., 18 6 1, 296. 
Banks, Cat. Heur. Ins. H. S., 1907, 41. Ulmer, Gen. In- 
sectorum, Fasc. 60, 1907, 210. 
Imago. —“Rufo-fuscous; antennae and palpi rufo-fuscous; 
head and thorax brownish-black; feet testaceous; abdomen dute¬ 
ous ; wings fusco-hyaline, with fuscous veins; anterior ones with 
dense luteous guttae. Male. 
Length to tip of wings, 10 mm. Alar expanse 19 mm.” 
(Hagen) 
Larva. —Length, 14-16 mm. Width, 2.3 mm. The greatest 
width is about at the middle of the body,—the third or fourth 
abdominal segment, the head and the last segment being much 
smaller. Abdomen yellowish, reddish-brown above, a double 
line of yellowish extending along the dorsal side. This reddish 
coloration does not dissolve in preserving fluid. Head, prothorax, 
