282 ENTOMOLOGY 
feeders, however, seem not to pass through this stage, but to 
adopt the limophagous habit as soon as they cease to depend 
upon Entomostraca. 
“Terrestrial insects, dropping into the water accidentally 
or swept in by rains, are evidently diligently sought and 
largely depended upon by several species, such as the pirate 
perch, the brook minnow, the top minnows or_ killifishes 
(cyprinodonts), the toothed herring and several cyprinoids 
(Semotilus, Pimephales and Notropis). 
“ Among aquatic insects, minute slender dipterous larvee, 
belonging mostly to Chironomus, Corethra and allied genera. 
are of remarkable importance, making, in fact, nearly one 
tenth of the food of all the fishes studied. They are most 
abundant in Phenacobius and Etheostoma, which genera have 
become especially adapted to the search for these insect forms 
in shallow rocky streams. Next | found them most generally 
in the pirate perch, the brook silversides, and the stickleback, 
in which they averaged forty-five per cent. They amounted 
to about one third the food of fishes as large and important 
as the red horse and the river carp, and made nearly one fourth 
that of fifty-one buffalo fishes. They appear further in con- 
siderable quantity in the food of a number of the minnow 
family (Notropis, Pimephales, etc.), which habitually fre- 
quent the swift waters of stony streams, but were curiously 
deficient in the small collection of miller’s thumbs (Cottidz ) 
which hunt for food in similar situations. ‘The sunfishes eat 
but few of this important group, the average of the family 
being only six per cent. 
“ Larve of aquatic beetles, notwithstanding the abundance 
of some of the forms, occurred in only insignificant ratios, but 
were taken by fifty-six specimens, belonging to nineteen of the 
species,—imore frequently by the sunfishes than by any other 
group. The kinds most commonly captured were larvee of 
Gyrinide and Hydrophilide ; whereas the adult surface beetles 
themselves (Gyrinus, Dineutes, etc.)—whose zigzag-darting 
swarms no one can haye failed to notice—were not once en- 
countered in my studies. 
