186 FISHES OF ILLINOIS 



only .28. These species resemble- each other so closely that they 

 are not often distinguished by fishermen, and their food and habits 

 are virtually identical. Their mutual rivalries might hence result 

 to their common disad\^antage except for a partial avoidance of 

 competition by a difference of local and ecological preference. Our 

 collection data indicate for this species a strong preference for muddy 

 water, its frequency coefficient for streams with a mud bottom 

 being 1.72. Consistent with this fact is its distribution in the lower 

 Illinoisan glaciation. We have found it in all our river basins, in- 

 cluding the Michigan drainage area and the northeastern glacial 

 lakes, but have not taken it in the extreme northwestern part of the 

 state. It has also been absent in our collections from the main 

 streams of the Wabash, the Ohio, and the Mississippi, and from the 

 short creeks of the Mississippi bluff's. It seems with us to be more 

 abundant southward, and has occurred with the greatest frequency 

 in the streams of the Wabash Valley. 



It is generally distributed from Lakes Erie and Huron and the 

 smaller lakes of Ontario to North Carolina and the Florida penin- 

 sula, the Alabama River, and Texas. It occurs also in the Arkansas 

 River and up the Missouri to South Dakota. It is one of the com- 

 monest and best known bullheads throughout its range. 



As illustrated by the food of a dozen specimens, this species has 

 the habits of a scavenger. One of these fishes had gorged itself with 

 the waste of a fish boat, and one had made the greater part of its last 

 meal from the remnants of a dead cat. Three of these specimens 

 had eaten fishes taken alive, and four others had eaten crawfishes. 

 May-fly larvae and a few water-snails were the only other objects 

 worth mentioning. Seven young specimens, from two to three and 

 a half inches long, had fed principally on Entomostraca, the remain- 

 der of their food being chiefly small mollusks and insect larvse. 



This fish is distinguished from the brown bullhead {A . nebulosus) 

 only by the more observant of our fishermen, some of whom call it 

 "greaser" or "slick bullhead," its skin being very thin, and the fish, 

 in consequence, particularly hard to dress. Its maximum weight 

 is H to 2 tb. 



The yellow bullhead spawned at Havana in May in 1898 (Craig). 

 Females with ripe spawn were seen in market at Meredosia on May 

 24, 1900 (Large). In the words of T)r. Jordan these fishes are "small, 

 but good eating," as we have ourselves proven. 



