Bulletin Wisconsin Natural History Society [Vol. 13, No. 1 
Special Characters. Length 12-13 mm., width 1.7-2 mm. 
Head brown to dark brown. Mandibles three-toothed; labrum, and 
clypeus of typical shape. Clypeus with the dotted triangular or A — figure 
peculiar to many Limnephilid larvae; this figure may be incomplete or 
absent, although pits will be found on the clypeus arranged in some irregu- 
lar fashion. Pits of the head small, unpigmented. Thorax with the usual 
plates, metanotum with the typical number. 
Abdomen: I with three tubercles, one mid-dorsal; this latter tubercle 
quite large, extending posteriorly; a row of about 10-12 black bristles on 
each side of the dorsal tubercle. Ill to VII naked, except for a long 
dorso-lateral bristle medially each side of the mid-line. VIII with a 
posterior fringe of long bristles. On IX a chitinous plate dorsally with 
about 12-16 bristles, four of which are very long. Dragger and plate shown 
in figure 1, D. Gill filaments simple, absent on I, VIII, and IX (fig. 3) 
Lateral line distinct, with fringe of black hair. 
Fig. 3. Asynarchus simplex Banks. Larva. Showing Position and 
Number of Gill Filaments. 
Legs yellow, spines yellow, bristles black.’ Anterior femur with two 
spines on distal part, two on the short basal portion, an additional “ spine” 
or ‘‘bristle” over the second femoral spine (fig. 2 , A). 
Case. Length 8-11 mm., width 2-3 mm. Conical, open at smaller end, 
tapering. Made of small bits of plant fiber and sand. There is some 
variation in this, for in several instances the cases are made nearly entirely 
of sand granules. 
Described from over a dozen specimens representing various 
stages in the life of the larva. The smallest larva is about 5 
mm. in length, the largest 13 mm. About eight cases are repre- 
sented in the material. This material is mixed in with a large 
catch of Entomostraca from Upper Ice House Lake, St. Paul 
Island, Pribilof Islands, Alaska, collected August 7,1906, by Dr. 
M. C. Marsh, of the U. S. Bureau of Fisheries. 
