206 Journal New York Entomological Society. [Voi. xxiii, 



fibers from submerged sticks. The stomachs examined contained 

 particles of higher plant tissue in all stages of preservation, as well 

 as many algae, but decaying tissue was always in greatest abundance. 

 The dominance of decaying tissue in the stomachs may be explained 

 by a glance at their habitat during spring, before the period of pupa- 

 tion. At this time the pools are full of dead and decaying cat-tails 

 and sedges ; living plants are relatively rare. The alg?e are appar- 

 ently swallowed accidentally with the larger plants over which, in 

 these pools, they form a thick scum. 



Pupil Habits. — Early in May, close examination of a pond where 

 the larvae had been found in great abundance, covering the bottom 

 with an 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 numbers 

 that they could be brought out by the handfull from every tussock. 

 Well hidden as they were, their hiding place 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 re- 

 moved. Muskrat feces taken from these locations and disintegrated 

 in water revealed enough chitinous fragments to indicate that the 

 caddis pupse were an important article of diet at this season. 



On emerging the pupse come to the surface and swim about, ap- 

 parently blindly, until they encounter some suitable support project- 

 ing 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 nearby bush or, as dusk changed to darkness, flew over the 

 pond. 



Description of Larv^, Pupa and Case. 



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 parts of this larva is caused by 

 a coating which can, with difficulty, be removed, leaving the skin 



