The Food of Fishes. 
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Food of the Adults. 
An examination of the notes on the twenty-seven 
adults shows material differences of food at different 
parts of the year. As all but one were taken from the 
Illinois River, I have not the means of noting* the corre- 
spondence of food with locality. 
Five specimens taken at Peoria, in March, were found 
feeding* most freely upon Oladocera, which composed 
fifty-five per cent, of tlieir food. These were chiefly of 
the two species Simocephalus vet ulus and S. americanus. 
These little Entomostraea were taken at that time in 
such quantity as visibly to distend the stomach when seen 
from the outside, and the immense number of their eggs 
gave a reddish color to the contents of the alimentary 
canal. The larvae of Neuroptera, both u darning-needles 9 9 
and May-flies (Palingenia), were also eaten in consider- 
able numbers (thirty-nine per cent.). A small Hybopis, 
a little darter ( Boleosoma metadata) and an unrecog- 
nizable fish were found in these stomachs, making about 
six per cent, of the food. Only trivial numbers of Ento- 
mostraca appear after this time. 
Nine specimens, taken in April, likewise at Peoria, 
were feeding chiefly upon Neuroptera larvae (eighty-six 
per cent.), especially upon that almost invaluable ele- 
ment of fish food, the larvae of Palingenia bilineata (six- 
ty-six per cent.). A few larvae of (fyrinidae and Dytis- 
cidae were noted (three per cent.), and a few Corixas also. 
A Gammarns fasciatus and a little Ceratophyllum, etc., 
were noticed ; and also the flower of an elm and the 
feather of a bird. 
A single specimen from Pistakee Lake, in McHenry 
county, taken in May, gave evidence of a similar reliance 
upon Neuropterous larvae (eighty-five per cent.). Here, 
however, in the absence of Palingenia, Agrions and the 
larger dragon-flies were resorted to. A little vegetation 
had been taken with these ( Ceratophyllum denier sum and 
Lenina trisulca ten per cent.), probably by accident, as 
this lake was full of aquatic plants, and it would hardly 
have been possible for a fish to catch living food from the 
water without getting more or less vegetation at the 
same time. A single Hymenopter — the only land insect 
