70 
The Food of Fishes . 
In a specimen two inches long, the Chironomus larvae fell 
to fifteen per cent., while the Palingenia larvae rose to 
eighty per cent., and other Ephemerids and Cyclops 
made np the remainder of the food. 
Four specimens, also from the Ohio, at Cairo, from 
two to four inches long, were found to have recently fed 
upon Ephemerid larvae and larvae of aquatic beetles, 
Cyrinidae and Hydrophilidae, in about equal quantities. 
Only five per cent, of their food was Chironomus. 
Sixteen individuals of medium size were taken from 
the Illinois and Ohio rivers, in April, June, September 
and October of four different years. There was nothing 
in the contents of these stomachs to indicate any differ- 
ence in food resulting from these differences of date and 
situation. The food, on the contrary, was remarkably 
simple and uniform, consisting chiefly of the larvae of 
Neuroptera (eighty-four per cent.), of which Palingenia 
bilineata formed altogether the most important part 
(seventy-six per cent.) — the remaining eight per cent, 
being dragon-flies. A single small sucker (Catostomidae), 
a few mollusks (Planorbis, young Unios and thin-shelled 
Anodontas), and some Aselli complete the brief dietary 
of this group. 
It is not until we examine the food of full-grown speci- 
mens that we wholly appreciate the utility of the enor- 
mous crushing pharyngeal jaws with their pavement 
teeth, found in this species. The entire food of the three 
large specimens examined, taken at Peoria, in April and 
October, proved to consist of mollusks only, including 
forty-six per cent, of the thick and heavy water snail, 
Melantho decisa, whose shell probably no other fish in 
our rivers could break. Cyclas, Anodonta and indeterm- 
inable Gasteropoda composed the remainder of the food. 
