HYBOPSIS 169 



lina and Alabama, our collections in the state of Illinois are 

 limited to the more recently glaciated areas, only one having 

 been made bj^ us below the southern boundary of the Wisconsin 

 glaciation. Against this single locality in southern Illinois 

 (Union county) we have 122 localities in the northern two thirds 

 of the state, where the species is not only abundant but is 

 generally distributed, mainly in the smaller streams and also in 

 the glacial lakes of the northeastern section. We have taken it 

 from Lake Michigan at Chicago. 



According to our 137 collections of the horny-head, it is 

 almost wholly a species of the creeks and smaller rivers, the 

 frequency coefficient for the first being 3.08 and for the second 

 2.47. It has been so rare in stagnant waters that we have taken 

 it but twice in our 591 collections from lakes and ponds. From 

 the larger rivers we have obtained it 6 times in 293 collections. 

 It seems to be with us especially a fish of swift waters and a 

 hard bottom, the coefficient for the former class of situations 

 being 1.38 and for the latter 2.24. It is consistent with this 

 fact that, although commonly scattered throughout the Wis- 

 consin glaciation, it stops short at the southern boundary of 

 this area, not entering the lower Illinoisan at any point. 



The spawning season of this species is late May and early 

 June. In spring males the top of the head is swollen to form 

 a kind of crest, which may be considerably higher than the 

 level of the neck, and is covered with large tubercles. 



The length of ten inches which this fish sometimes attains, 

 perhaps accounts for the rather prominent appearance of craw- 

 fishes in its food. Thirteen specimens from northern and central 

 Illinois had derived less than half their food from the animal 

 kingdom, about a fourth of it consisting of insects, largely case- 

 worms and other larvae of Neuroptera, another fourth of craw- 

 fishes, eaten by two of the specimens. The vegetable food was 

 about equally divided between thread algse and seeds of grasses. 

 Although insects appear in relatively small ratio, two of these 

 fishes had eaten nothing else, and another had eaten 95 per 

 cent, of aquatic larvae. Two other specimens had taken only 

 vegetation, which also composed 80 per cent, of the food of 

 three additional. It will be noticed that the alimentary canal 

 of this minnow is of more than average length, a fact probably 

 related to its vegetarian habit. As a game fish, according to 

 Jordan and Evermann, it is the most active and vigorous of its 

 tribe. ^^Any sort of hook baited with an angleworm or white 



—20 P 



