NORTH AMERICAN CADDIS-FLY LARVE. 
In view of this discrepancy in habitat, and also in the difference 
of size of both adults and larve, it seems probable that there are 
more than one species in the genus. Dr. Betten, however, after 
careful study of a large number of adults, could find no characters 
for distinction, except size, and recognizes but one American 
species in the genus. 
Hasits.—In many of the streams about Ithaca the larve are 
very abundant, but are difficult to discover during larval life, while 
they live among the sand and gravel of the stream’s bottom. 
Shortly before pupation they attach their cases firmly to some sub- 
merged rock or log, usually selecting a rough surface. At this 
time they often display a gregarious instinct, large numbers con- 
gregating within a very small area. It is during the prepupal and 
pupal periods that they are most often collected. 
PrEriop oF EMERGING.—Adults emerge from the latter part of 
June until the end of July. 
Description oF LArvA.—Length, 6 mm. The larva, when re- 
moved from case, assumes a spiral position of at least one and a 
fourth turns. 
HELICOPSYCHE BOREALIS. 
124. Larva. Head and thorax. 127. Larva. Chitinous support, 
125. Larva. Frons. middle leg. 
126. Larva. Drag-hook. 128. Case. 
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