44 The Food of Fishes. 
Micropterus salmoides, Lac. Small-mouthed Black 
Bass. >v 
This species, called also tiger bass, river bass, etc., is 
the black bass par excellence. It ranges usually in deeper 
and clearer water than the preceding ; but both are often 
taken together. 
I have made full notes of the food of twenty-seven spec- 
imens— three adult and the others young. I had none of 
this species under an inch in length; but, judging from 
the general resemblance of the food of this and the pre- 
ceding bass at later ages, I do not doubt that this will also 
be found to feed at first on Entomostraca, although insect 
food is possibly more important to it from the beginning. 
Seven individuals, from one to two inches in length, 
were all taken in July from rocky ripples in the Fox 
River, at Dayton, 111., a few miles above the mouth of the 
stream. These had eaten only five per cent, of Entomos- 
traca — the whole remainder of the food consisting of in- 
sects, of which Corixa tumida, young and adult, and 
larvae of May-flies and darning-needles (Agrionidae) were 
the most important kinds. Four per cent, of the larvae of 
Chironomus are worthy of notice. The scarcity of Ento- 
mostraca in the food of fishes as small as these is prob- 
ably due to the situation in which these specimens oc- 
curred, as few Entomostraca are to be found in swift 
water. The same fact will account for the presence of 
Chironomus larvae — found abundantly under stones in 
rapid streams. 
The next ten specimens, between two and three inches 
long, were taken in July, partly at the same place as the 
preceding, and partly from the Illinois River, a few miles 
below the mouth of the Fox. These differed from the 
smaller specimens chiefly in the appearance of fishes in 
the food (five per cent.) and in the absence of Neurop- 
tera. Probably the last of these differences, at least, was 
accidental. A few larvss of aquatic Coleoptera (Hyd.ro- 
philidic and Dytiscidae) were noticed. Corixas, including 
C. tumida , Uhl, and C. signata, Ficb.,* amounted to 
eighty-two per cent, of the food. 
In those ranging from three to four inches in length 
(seven individuals), the fishes eaten rise to fourteen per 
Determined by Mr. Uhler. 
