NORTH AMERICAN CADDIS-FLY LARVZE. 
on the prothorax and extend to the hind margin of the metathorax. 
Each epimeron is marked with dark-brown. 
The legs are straw-yellow with a dark-brown mark on the 
front of each coxa. 
The Abdomen.—The abdomen is marked on its upper surface 
with two parallel dark stripes, which form continuations of the 
thoracic markings. These marks are less conspicuous than those 
of the thorax and become fainter as they reach the caudal seg- 
ments. 
The gill arrangement is shown in figure 23. The caudal gill is 
lacking from the ventral series and segment 8 is without gills. 
PHRYGANEA INTERRUPTA. 
LarvaL Hapsrrat.—In the region of Ithaca larve of P. inter- 
rupta have been taken, together with those of P. vestita in Michi- 
gan Pond and in the pools about the University Biological Field 
Station. Vorhies, who reared this species at Madison, Wisconsin, 
found it common in several situations of standing water “where 
Elodea occurs.” In our locality the species is found in some situ- 
ations where no Elodea grows, and it seems to us improbable that 
the presence of Elodea has any influence on the distribution of the 
larve. 
LARVAL Hasits.—The activities of the larve, so far as known, 
are like those of P. vestita. 
Although pupation takes place and the adults are on the wing 
together with those of P. vestita, the larve obtain their growth 
very much sooner than those of that species. By the first of Jan- 
uary the larve of P. interrupta have obtained full growth, measur- 
ing thirty millimeters in length. At the same time the larve of 
P. vestita, from the same situation, measure only twelve to twenty 
millimeters in length. 
In preparing to pupate, the habits of this species do not differ 
from those of P. vestita. 
Prriop oF EmMEeRcING.—Adults emerged from the last of May 
until the latter part of June. 
Foop oF THE Larvai.—The stomachs of specimens examined 
contained about the same proportion of dead and green plant tissue 
found in the stomachs of P. vestita. 
32 : 
