178 NEW YORK STATE MUSEUM 



The food differences of the three groups are interesting and sig- 

 nificant. That of the smallest lot (too small, judging by the preced- 

 ing study, to be selected by bullheads for food) was predominantly 

 Entomostraca, especially Copepods, with a considerable propor- 

 tion of midge larvae. The food of the second lot was predominantly 

 small snails and midges, with an occasional abundance of Copepods. 

 The food of the larger ones was predominantly May flies, and 

 midge larvae and pupae, with a sprinkling of other insects. Indeed, 

 the table understates the difference between the food of the three 

 lots for the midge larvae eaten by the fishes of lot three were as 

 a rule much smaller than those eaten by the larger fish. 



Notes on the constituents of the food. The beetles eaten 

 were all adults. They were eaten only by the larger fish. There 

 were but three of them, however ; a ground beetle by number 5 

 (and this may have fallen into the water by accident), and 2 Parnid 

 beetles by fish number 2. Beetles of this latter family are very 

 commonly found crawling about on the under surface of submerged 

 logs or hiding in their crevices. They stick closely to the surface, 

 their long legs widely outspread, and they hold fast with their 

 huge grappling claws and are not easily dislodged. 



Only five larvae of caddis flies were eaten, and these appeared to 

 have been separated from their cases, not swallowed in them as 

 were those fed upon by the brook trout of Bone pond at Saranac 

 Inn [see N. Y. State Mus. Bui. 68, p. 204]. No case construction 

 material was found with them, but the larvae appeared to be such 

 as usually construct their cases out of plant stems. They have 

 been preserved for future determination. 



Midges on the contrary (family Chironomidae) formed a large 

 percentage of the food of the sunfish of all sizes. The smaller 

 larvae, however, were eaten by the smallest fish, as already noted, 

 and the larger larvae and pupae, only by the larger ones. Every 

 study of fish food hitherto made has emphasized the great eco- 

 logical importance of this group. 



No May flies were eaten by the fish of lot three, but the larger 

 fish had eaten them very freely — two of them (number 6 and 16) 

 in great abundance. Number 2 had eaten a burrowing nymph of 

 the genus Ephemera along with a dozen Caenis. All the others 

 eaten by all the fishes were Caenis d i m i n u t a . This is the 

 little white May fly already mentioned as swarming to our trap 

 lantern when set on the hatchery pier. It is the most ephemeral 

 of all Ephemera. It emerges from the water at nightfall, leaving 



