NORTH AMERICAN CADDIS-FLY LARVZE. 
almost unbroken mass of moving cases, at first revealed not one 
inhabited larval or pupal case. They were not on the bottom, nor 
were they clinging to the vegetation, as is the habit of some species 
of the genus when pupating, nor were they under sticks or logs, 
nor in crevices. At last they were found deep down among the 
fibrous roots of sedge tussocks. Here they occurred in such num- 
bers that they could be brought out by the handful from every 
tussock. Well hidden, as they were, their hiding places had been 
found by the muskrats of the region. Stumps and floating logs 
were piled by the rats with broken pupal cases from which the 
contents had been removed. Muskrat feces taken from these lo- 
cations and disintegrated in water revealed enough chitinous frag- 
ments to indicate that the caddis-pupe were an important article 
of diet at this season. 
On emerging, the pupze come to the surface and swim about, 
apparently blindly, until they encounter some suitable support pro- 
jecting above the water, where, climbing a few inches above the 
surface, they transform. The greatest number of adults were on 
the wing during the middle of May. At this time swarms of them 
clung to every near-by bush, or, as dusk changed to darkness, flew 
over the pond. 
Foop oF THE LArva#.—The larve eat vegetable matter, living 
or dead, with little discrimination for species or condition of pres- 
ervation. ‘They may readily be seen browsing on dead and de- 
caying cat-tail or sedge, or on living plant tissue, or scraping loose 
fibers from submerged sticks. The stomachs examined contained 
particles of higher plant tissue in all stages of preservation, as well 
as many alge, but decaying tissue was always in greatest abun- 
dance. The dominance of decaying tissue in the stomachs may be 
explained by a glance at their habitat during spring, before the 
period of pupation. At this time the pools are full of dead and 
decaying cat-tails and sedges; living plants are relatively rare. 
The alge are apparently swallowed accidentally with the larger 
plants over which, in these pools, they form a thick scum. 
DESCRIPTION OF THE LArvA.—Length, when mature, 18—21 
mm.; breadth, 3.5—4.5 mm. The color of the heavily chitinized 
parts is brown; the abdomen and weakly chitinized parts are white 
in young specimens, and rusty brown in individuals that are almost 
ready to pupate. The rust-like appearance of the weakly chitinized 
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