296 FISHES OF ILLINOIS 



It occurs virtually everywhere in the state except in the larger 

 streams and in lowland lakes and sloughs, where it is strikingly rare. 

 It has occurred but twice, for example, in over five hundred collec- 

 tions made by us from the Illinois River at Havana and Meredosia. 

 It is rather disproportionately infrequent in the waters of the lower 

 Illinoisan glaciation, although not by any means excluded from that 

 area, as a glance at the distribution map for the species will show. 

 We have found it most abundant in the small streams of the Wabash 

 and Kaskaskia systems, in which it has occurred in 56 and 66 per 

 cent., respectively, of all collections made. 



It is typically a darter of the creeks and small brooks, and 44 per 

 cent, of all our creek collections have contained it. It has come 

 from the smaller rivers with about half this frequency, and from 

 glacial lakes with about a fourth. The average character here 

 ascribed to it is illustrated by the fact that it has been taken by us 

 with darters of other species in almost exactly the average frequency 

 of the associate occurrence of one species with another throughout 

 the whole subfamily. 



It is usually found among gravel and weeds, although not infre- 

 quently on a mud bottom, from which situation some 1 1 per cent, of 

 our collections came. Its preference for swift waters is not so 

 marked as in the case of the more typical darters, nearly a third of 

 our collections having come from standing or quiet water. 



Outside Illinois the species is found from New England and Lake 

 Champlain through the Great Lake region to the Assiniboin River, 

 down the Atlantic slope as far as the Catawba River, and westward 

 throughout the Ohio and Missouri basins to Colorado and Montana. 



Its habits are those of its subfamily. It often lies with its head up 

 and its body bent to one side or supported partly by a stone. It can 

 turn its head without moving its body ; can roll the eye about in the 

 socket; may rest suspended, as we have seen it do, on the underside 

 of a floating board ; and sometimes buries itself, with a whirl, in the 

 soft sand, so that only its eyes are visible. 



The food of a dozen specimens was so uniform that they may 

 fairly be taken as representative Two thirds of it consisted solely 

 of Chironomus larvse, 7 per cent, of other minute larvae of gnats, and 

 the remaining 12 per cent, of larvae of small May-flies. 



The species spawns in spring, from the last of April to the first of 

 June. Females were depositing their eggs in our aquarium at Mere- 

 dosia, April 28 and 29, 1899. In the act of spawning the male rode 

 on the back of the female, with ventrals astride, and pectorals and 

 ventrals in active vibration as the pair moved about on the bottom. 



