238 ENTOMOLOGY 



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 I found them most gener- 

 ally 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 considerable 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 (Cottidae) 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. 



"Larvae 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, more fre- 

 quently by the sunfishes than by any other group. The kinds most 

 commonly captured were larvae of Gyrinidae and Hydrophilidae ; where- 

 as the adult surface beetles themselves (Gyrinus, Dineutes, etc.) whose 

 zigzag-darting swarms no one can have failed to notice were not once 

 encountered in my studies. 



"The almost equally well-known slender water-skippers [Gerris] seem 

 also completely protected by their habits and activity from capture 

 by fishes, only a single specimen occurring in the food of all my specimens. 

 Indeed, the true water bugs (Hemiptera) were generally rare, with the 

 exception of the small soft-bodied genus Corixa which was taken by 

 one hundred and ten specimens, belonging to twenty-seven species, 

 most abundantly by the sunfishes and top minnows. 



"From the order Neuroptera [in the broad sense] fishes draw a 

 larger part of their food than from any other single group. In fact, 

 nearly a fifth of the entire amount of food consumed by all the adult 

 fishes examined by me consisted of aquatic larvae of this order, the great- 

 er part of them larvae of day flies (Ephemeridae); principally of the genus 

 Hexagenia. These neuropterous larvae were eaten especially by the 

 miller's thumb, the sheepshead, the white and striped bass, the common 

 perch, thirteen species of the darters, both the black bass, seven of the 

 sunfishes, the rock bass and the croppies, the pirate perch, the brook 

 silversides, the sticklebacks, the mud minnow, the top minnows, the 

 gizzard shad, the toothed herring, twelve species each of the true 

 minnow family and of the suckers and buffalo, five catfishes, the dog- 



