AQUATIC INSECTS IN NEW YORK STATE 207 
Professor Forbes in his studies of Illinois fishes (the brook 
trout was not one of the fishes he studied), has clearly pointed 
out the importance of these small larvae as fish food: “ Among 
aquatic insects, minute slender dipterous larvae, belonging 
mostly to Chironomus, Corethra and allied genera, are of re- 
markable importance, making, in fact, nearly one tenth of the 
food of all the fishes studied.’! In his report? on the aauatic 
invertebrate fauna of the Yellowstone national park, almost 
every page testifies to the abundance, general distribution and 
ecological importance of Chironomus. On page 228 are given 
some observations indicating that it is of as great importance 
to young trout as to adults: 
_ The pond was swarming with mountain trout (Salmo 
mykiss), a few of which I dissected for a determination of 
their food. One of these an inch and a half in length had eaten 
Chironomus larvae and imagos chiefly, the remainder of its 
latest meal consisting of other insect larvae, not in condition 
to identify, and the entomostrachan Polyphemus pedi- 
eulus. A second, an inch and a quarter long, had also fed 
on Chironomus in its various stages of larva, pupa and imago, 
but had made about a third of its meal of Entomostracha. 
Another, still smaller (.92 of an inch long) taken from the open 
lake among the small weeds growing on a flat, muddy rock, had 
filled itself with Chironomus pupae only, as had still another 
of the same size. A third specimen from this situation had 
eaten more larvae of Simulium than of Chironomus, and a 
fourth had also eaten Simulium larva and another dipterous 
larva unknown to me. I may add here that other young trout, 
in a small swift rivulet near the Lake hotel, were feeding con- 
tinuously, Aug. 9, on floating winged insects, mostly, if not all, 
Chironomus and smaller gnatlike forms. 
With these certain indications of the economic importance of 
the genus at hand, it is indeed time we were able to recognize 
its species. Mr Johannsen’s work in part 8 is a beginning in 
that direction. All the above mentioned references, as well as 
most others to immature stages wherever published, are to the 
genus only; and Chironomus is a great genus, and includes 
forms with considerable diversity of structure, habitat and 
1Tll. State Lab. Nat. Hist. Bul. 2, p.483. 
*U. S. Fish Com. Bul. 11, p.207-56. 
