DESCRIPTION OF A TRICHOPTEROUS LARVA FROM 
THE PRIBILOF ISLANDS, ALASKA* 
By Richard A. Muttkowski 
While collaborating with Mr. J uday in a study of some Entomos- 
traca from the Pribilof Islands 1 the writer obtained a number 
of specimens of an undescribed trichopterous larva. As the spe- 
cies seemed to be quite common among the Crustacea it was 
evident that an attempt toward identification would not suffer 
for lack of material. 
Although our knowledge of the larval stages of North American 
Trichoptera is exceedingly meager, it was possible to determine 
by means of Ulmer’s excellent tables 2 for European forms that 
the larvae belonged in a division of Limnephilidae from which 
only a few forms had been described. The position of the caddis- 
fly seemed to be in a group containing Drasus, Halesus, Stenophy- 
lax, and other caddis-fly genera, and the probabilities were that 
the form belonged to the holarctic genus Asynarchus. It was 
later discovered that Banks 3 had described a species of Asynarchus 
from St. Paul Island, the chief island of the group. This species 
is Asynarchus simplex Banks; the writer does not hesitate to 
refer the present larva to this species of Asynarchus. 
Asynarchus simplex Banks, larva. 
General Characters. Tibial spurs 2, 2, 2. Lateral fringe distinct, 
black. Gill filaments single, unbranched, absent from segment one of 
abdomen. Horn of prosternum present. Head brown, no dark markings, 
in cleared specimens with lighter colored circular pits of the size of pig- 
ments spots such as are found in many Limnephilidae. 
* Published by permission of the Commissioner of Fisheries. 
1 C. Juday and R. A. Muttkowski, Entomostraca from St. Paul Island, Alaska, Bull. Wis. 
N. H. Soc., (2) 13, pp. 23-31 ,1915. 
2 G. Ulmer, Trichopteren, Heft 5/6 of A. Brauer, Die Suswasserfauna Deutschlands, pp. 
1—326, 1909, 467 text figs. 
2 Nathan Banks, Papers from the Harriman Alaska Expedition. X. Entomological Results. 
4;: Neuropteroid Insects. Proc. Wash. Acad. Sci., 2, pp. 465-476, 1900. Asynarchus simplex, 
on p. 469, pi. 27, fig. 3. 
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