178 NEW YORK STATE MUSEUM 
The food differences of thé 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. Bul. 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 ee 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 
eae ly aill wae msines Wors Cacmis dimilmura. ‘Wins is tae 
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 
