1914] Biology of Net-Spinning Trichoptera 267 
Of the diatoms, Gomphonema, Cocconema and Navicula 
were the most abundant forms, though Synedra, Melosira, 
Encyonema and Fragillaria appeared in smaller numbers. 
Ulothrix and Oedogonium and Cladophora of the green 
alge were found all of the year, and in the spring and summer 
Merismopedia and Cilyndrospermum of the blue-greens ap- 
peared. 
Heptagenia nymphs, and Chironomus larve made up the 
bulk of the animal food, although Simulium larve and Ostracods 
were abundant. Difflugia shells were found a few times. 
These results do not agree with the statements of Wesenberg- 
Lund (1911) and Ussing (1907) that the larve are inactive, 
lying rolled up in a spiral and taking little or no food in the 
winter. The collection made in February came at a time when 
the Creek was covered with ice. The larve were found on the 
underside of stones in the strearh, either in a case of pebbles 
loosely held together or a mass of roots spun into a tubular 
form. When the stones were removed from the water and 
placed on the bank, the larve came out of their tunnels at once 
and crawled about over the stones. There was also an abund- 
ance of food in the stomach in every case. 
In examining the contents of the stomach of Chimarrha 
aterrima (Family Philopotamidz) one is greatly surprised to 
find vegetable food exclusively. The mandibles are strongly 
developed, with sharp teeth, and lack the median tuft com- 
pletely, which, according to Siltala, would point to an ex- 
clusively carnivorous form. Examinations were made on 
November 14, November 30, June 11 and July 14. On the first 
three dates, the stomach contents consisted of diatoms ex- 
clusively, the same forms as were found in the Hydropsychids. 
On the last date, however, Euglena was very abundant, as 
were the simple green alga Scenedesmus and other Protoccocales; 
also desmid zygospores. In every instance there was very 
much silt mixed in with the food. 
Only one examination of food was made on the two larve 
of the Family Polycentropide. This was on July 14, when 
ten specimens of each species were examined. The food of 
Polycentropus sp. was made up entirely of insects, Chirono- 
mids being the principal diet, and Heptagenia nymphs quite 
numerous. 
