AQUATIC IXSECTS 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 aquatic 

 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 ( S a 1 m o 

 mykiss), a few of which 1 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- 

 cuius. 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 Eutomostracha. 

 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 

 oaten 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 3 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 



nil. state Lab. Nat. Hist. Biil. 2. p.483. 

 ^U. S. Fish Com. Bui. 11, p.207-56. 



