7a 



Two species of mimiows, Chroftomus eri/thrnyaster and Srinotilns at rornacu- 

 latits — the tlrst represented by fourteen specimens iind the second by six, 

 all collected from a small tributary of the Fox, near Piano, Sept. 8, i882 — 

 were brought into comparison with reference to their food, with the result 

 that the characteristic dillVrences of the species, as shown in the general 

 discussion of the group published in our liulletin (i. Vol. I., were clearly 

 manifested by this small number. In the former lot seventy-five per cent, 

 of the food was mud, the remainder being indiscriminate vegetable de6W.s,- 

 while in the latter the entire mass consisted of insects (chiefly terrestrial) 

 except a single insect parasite (Gordius). 



From one of the permanent ponds or so-called lakes of southern Illinois, 

 covered in September with a film of Woltlia and other vegetation, three 

 specimens of Oamhusia patruelis and Ave of Umbra limi were examined. 

 The former had eaten little but Wolffla, which amounted to more than 

 ninety per cent, of the food, the remainder consisting of Entomostraca, 

 mollusks and aquatic insect larva^, while the Wolffla made less than sixty 

 per cent, of the food of the Umbra — about one-fourth consisting of Ento- 

 mostraca and the remainder of unrecognized insects. 



Two minnows of similar range [Phenacohius mirabilis and JSfotraijis whipplei) 

 agree essentially in gill structure and pharyngeal teeth, and differ but 

 little in the relative length of intestine, and they have consequently been 

 placed by me in the same alimentary group.* They are unlike, however, 

 in the form of the mouth and in their haunts and feeding habits. This 

 difference is reflected in the food of a small collection made in the Galena 

 river, in April, 1880, three specimens of Phenacobius having eaten only 

 aquatic larv* and pupa? (nearly all chirouomid), while the food of the 

 Notropis, represented by six specimens, was of a varied character, contain- 

 ing few aquatic larva? (only one per cent, of Chironomus), but consisting 

 chiefly of miscellaneous collections of terrestrial insects, seeds and anthers 

 of terrestrial plants, and other accidental rubbish. 



From a collection made at Henry, Illinois, I^ov. 1, 1887, four specimens 

 of croppie {Pomoxt/s nigromaculatus) are comparable with Ave sunfishes 

 [Lepomis 2)allidus), and three large-mouthed black bass [Micivpte^-us salmoides) 

 may be compared with three striped bass (Eoccus chri/so2)s). Eighty-four 

 per cent, of the food of the Pomoxys consisted of Hexagenia larva^, an 

 additional six per cent, being other aquatic larva?, and the remaining ten 

 per cent, consisting of fishes; while the Lepomis had eaten but twelve per 

 cent, of Hexagenia larvie, eight per cent, of other aquatic insects, and no 

 fishes at all — the remaining elements being terrestrial insects (about one- 

 fourth), worms (Nais and Lumbriculus, fifteen per cent.) and mollusks 

 (thirty-seven per cent.). 



The black bass had eaten chiefly fishes and a mouse, together with a 

 few aquatic insects, while the food of the striped bass was nearly all 

 ephemerid larva? with only a trace of fishes. 



A collection of small fishes, made from Mackinaw creek, in Woodford 

 county, August 20, 1871), affords an interesting opportunity to compare the 

 food of a number of the smaller species (cyprinoids, darters, etc.). About 

 half that of four specimens of Notropis megalops collected there consisted 

 of insects, the remainder being terrestrial and aquatic vegetation, and 

 substantially the same statement may be made with respect to six speci- 

 mens of Notropis whippJcl — these two species belonging respectively to the 

 third and fourth groups of my paper on the "Food of the Smaller Fresh 

 Water Fishes."* 



Two specimens of Hi/hopsis higidtatui^, on the other hand, had eaten only 

 aquatic vegetation, and two examples of Phenacobius — a species extremely 

 darter-like in its haunts and habits — had taken only Chironomus larva\ 



The darters were represented by four examples of Boleosoma and six of 

 Hadropterus, the former and smaller species having eaten mostly Chirono- 



*BiilL lU. St Lab. Nat Hist.. Vol. I., No. 6, p. 70. 



— 6 F. C. 



