80 
On the Food of Young Fishes. 
few Daphnids and Chironomus larvse. These were cer- 
tainly Amiurus, but it was of course impossible to tell 
the species. 
Other specimens of this genus, making thirteen in all, 
none longer than an inch and five-eighths, were obtained 
from various places on the Illinois, and from mud-lioles 
in the Mississippi bottoms, in Union Co. These thirteen 
individuals were feeding almost wholly on Entomostraca 
and larvse of Chironomus, the latter composing seventy- 
four per cent, and the former eighteen per cent, of their 
food. Twenty-two per cent, of Cladocera include Simo- 
cephalus americanus and S. vetulus, C'eriodaphnia andMa- 
crothrix laticornis ,* Jur., a species not hitherto reported 
from this country. Among the Lynceidse (ten per cent.) 
I recognized Chydorus, Pleuroxus dentatus , Alona and 
Eurycercus lamellatus , and among the Ostracoda a spe- 
cies of Candona answering precisely to the description of 
Candona bifasciata, Say. A few young Amphipoda and 
a few unknown insects’ eggs account for the remainder 
of the food. 
Six specimens of No turns sialis, varying in length from 
seven-eighths of an inch to an inch and a quarter, dif- 
fered from the foregoing in the much larger proportion 
of Chironomus larvse (forty-one per cent.) and in the 
twenty-six per cent, of young Allorchestes dentata — 
eaten by the larger specimens. These had .also taken 
seven per cent, larvse of Ephemeridse. Those under an 
inch in length were peculiar only in the large ratio of 
Chironomus larvse (sixty-five per cent.), a fact probably 
indicating that this species seeks its food chiefly on the 
muddy bottoms. 
No specimens of the other genera of catfishes were 
taken small enough to show their earliest food, but so far 
as can be judged from the food of four specimens of 
Ictalurus, from two and a half to three and a half inches 
long, the other genera will not be found to differ especial- 
ly from the foregoing. 
* Possibly this is not the species cited, but a careful comparison with 
the description and figures in Lilljeborg’s “Crustacea ex Ordinibus Tribus.” 
etc., failed to show any difference. 
