1880.] » The Food of the Darters. 699 
ganeidz). Sixty-six per cent. of the food was Chironomus larve, 
seven per cent. larve of other minute diptera (including Simu- 
lium), and the remaining eight per cent. was larve of small 
Ephemerids. 
I studied the food of two specimens of Pecilichthys variatus, 
four of P. spectabilis and two of P. asprigenis—making eight of 
the genus, representing six localities. Fifty-eight per cent. of 
small larvæ of diptera (forty-nine per cent. of Chironomus), 
thirty-two per cent. of larvæ and pupæ of small Ephemerids, and 
ten per cent. of case-worms made up the entire bill of fare. 
Percina caprodes, the largest of the group, departs from all the 
foregoing species by the introduction of crustacean food—thirty 
per cent. of Entomostraca and three per cent. the smallest of our 
Amphipoda, AU/orchestes dentata (Smith) Faxon. -Most of the 
Entomostraca were C/adocera, including Daphnia, Eurycercus and 
Daphnella1 
Here occurred the only instance of molluscan food in the 
group. One specimen had taken a few individuals of Ancylus 
rivularis Say. Reduced ratios of Chironomus and Ephemerid 
larvae, and a few Corixa tumida complete the list. 
Of Nanostoma zonale, less common than the others, but two 
individuals were examined, and these had eaten nothing but lar- 
ve of small diptera, including sixty-five per cent. of Chironomus. 
` Six specimens of Etheostoma flabellare var. lineolata, from four 
localities, had eaten sixty-one për cent. of Chironomus larve, 
twenty-seven per cent. larva of small ecg ae and twelve per 
cent. of Copepoda (Cyclops). 
Boleichthys elegans, found only in the southern part of the State 
(three specimens examined), had eaten only dipterous larvæ (thirty- 
Seven per cent.) and Ephemerid larvae (sixty-three per cent.). This 
is a larger, heavier species than most of the others, and, therefore, 
like Alvordius, prefers Ephemerids to gnats. 
Last and least comes Microperca punctulata, represented by 
nine specimens from four localities in Northern Illinois. This 
smallest of the darters shares with Percina, the largest, the pecu- 
iarity of crustacean food, which made up sixty-four per cent. of 
the total. The principal kinds were Cyclops, Chydorus, young 
* Daphnella was found in a Percina from the Calumet ihe? at South Chicago, but — 
hot in condition to permit the. determination of the speci a 
