Food Relations of Fresh-Water Fishes. 485 



nows, the gizzard shad, the toothed herring, twelve species 

 each of the true minnow family and of the suckers and buffalo, 

 five catfishes, the dog-fish, and the shovel fish, — seventy species 

 out of the eighty-seven which I have studied. 



Among the above, I found them the most important food 

 of the white bass, the toothed herring, the shovel fish (fifty-one 

 per cent.), and the croppies; while they made a fourth or more 

 of the alimentary contents of the sheepshead (forty-six per 

 cent.), the darters, the pirate perch, the common sunfishes 

 (Lepomis and Chsfinobryttus), the rock bass, the little pickerel, 

 and the common sucker (thirty-six per cent). 



Ephemerid larvas were eaten by two hundred and thirteen 

 specimens of forty-eight species — not counting young. The 

 larva3 of Hexagenia, one of the commonest of the '' river flies," 

 was by far the most important insect of this group, this alone 

 amounting to about half of all the Neuroptera eaten. They 

 made nearly one half of the food of the shovel fish, more than 

 one tenth that of the sunfishes, and the principal food resource 

 of half-grown sheepshead; but were rarely taken by the sucker 

 family, and made only five per cent, of the food of the catfish 

 group. 



The various larva? of the dragon flies, on the other hand, 

 were much less frequently encountered. They seemed to be 

 most abundant in the food of the grass pickerel, (twenty-five 

 per cent. ), and next to that, in the croppie, the pirate perch, and 

 the common perch (ten to thirteen per cent.). 



Case-worms (Phryganeida?) were somewhat rarely found, 

 rising to fifteen per cent, in the rock bass and twelve per cent, 

 in the minnows of the Hybopsis group, but otherwise averaging 

 from one to six per cent, in less than half of the species. 



THE CRUSTACEAN ELEMENT. 



Of the four principal classes of the animal food of fishes; 

 viz., fishes, mollusks, insects, and Crustacea, the latter stand third 

 in importance according to my observations, mollusks alone 

 being inferior to them. That insect larva? should be more 

 abundant in the food of fresh-water fishes than are crustaceans, 

 is a somewhat unexpected fact, but while the former made about 



