The FooiJ of Fis/irs. 25 



The genus Boleosotna^ regarded by Dr. Jordan as the typ- 

 ical darter, was represented by twelve specimens from 

 eight localities — nine of //laculatmn, two of ohnstedl and one 

 of ca7nu7'um.* These specimens show but slight food differ- 

 ences from other darters of similar size, the only notable 

 variation being the appearance of fifteen per cent, of case- 

 worms (larva^ of Phryganeidas). Sixty-six per cent, of 

 the food was Ohirononuis larvff , seven per cent, larvee of 

 other minute Diptera, and the remaining twelve per cent, 

 was larvEe of small ephemerids, and a few Cyclops. 



I studied the food of two specimens of Pmclllchthys va- 

 riatus^ four of P. spectabilis, and two of P. asprigenis — 

 making eight of the genus, representing six localities. 

 Fifty-eight percent, of small larvae of Diptera (forty-nine 

 per cent, of Chironomus), thirty-two per cent, of larvse 

 and pupge of small ephemerids, and ten per cent, of case- 

 worms made up the entire bill of fare. 



Percina caprodes-, the largest of the group, departs from 

 all the foregoing sj)ecies by the prominence given to crus- 

 tacean food — thirty per cent, of Entomostraca and three 

 I)er cent, of the smallest of our Am.^\\\\)0(\.ix^Allorchestesden- 

 tata^ (Smith) Faxon. Most of the Entomostraca were Cla- 

 docera, including Daphnia, Eurycercus, and Daphnella.f 



Here occurred the only instance of moUuscan food in the 

 group. One specimen had taken a few individuals of An- 

 cylus r'tvularis. Say. Reduced ratios of Chironomus and 

 ephemerid larvse, and a few Corixa tumida complete the 

 list. 



Of Nanostoma zonale^ less common than the others, but 

 two individuals were examined, and these had eaten 

 nothing but larvae of small Diptera, including sixty-five 

 per cent, of Chironomus. 



Six specimens of Etheostoma HabellaTe var. llneolata^ 

 from four localities, had eaten sixty-one per cent, of Chi- 



*Bo/eosoma miicitlaturn and R.ohnstedi %\\o\A^ undoubtedly be united. 

 Specimens in the laboratory collection present the extremes of both 

 forms, together with numerous intermediate stages of each character 

 used to distinguish them. 



This whole group exhibits a surprising variability, perhaps due to its 

 comparatively recent origin. 



tDaphnella was found in a Percina from the Calumet River, at South 

 Chicago, but not in condition to permit the determination of the species. 



