320 FISHES OF ILLINOIS 



central part of the state (1.7), about half as common in the 

 northern part as in the central, and a fourth as common in 

 southern Illinois. 



It is a fish of the lakes and deeper rivers from New Bruns- 

 wick, the St. Lawrence River, and the Great Lakes through the 

 Ohio basin to Minnesota, Kansas, and Iowa. Its center of 

 abundance is in the Great Lake region, but it is also distributed 

 widely over the Ohio basin and the northern part of the Missis- 

 sippi Valley. 



It ranks well as a food fish, some regarding it as scarcely 

 inferior to the black bass — and it is a game fish of some im- 

 portance, to be caught with live minnows or even with grubs 

 and angleworms. It will also rise to the fly. 



It was formerly much more common than now. We are 

 informed by Mr. H. L. Ashlock that a dozen years ago one could 

 easily get a hundred pounds of it in an afternoon at Alton with 

 a hundred-yard trammel-net, but that it has now almost dis- 

 appeared. It reaches a weight of one to three pounds and a 

 length of more than a foot. 



The little that is known of its food indicates that it is mainly 

 insectivorous, feeding especially upon the large May-fly larvae to 

 be found in immense numbers at the bottoms of our streams 

 and lakes, but taking also medium-sized crustaceans (Asellus), 

 and occasional fishes, among which sunfishes (Centrarchidce) 

 have been recognized. 



Its range, local preferences, feeding habits, and food are so 

 similar to those of the brassy bass (Morone interrupta) that the 

 two species have been taken together with uncommon frequency 

 in our collections, giving us the unusually high associative coeffi- 

 cient of 5.21. The occurrence of both these species in our terri- 

 tory is, in fact, due to an overlapping of the edges of the areas of 

 their distribution. One being a northern species and the other a 

 southern one, competition is mainly evaded, notwithstanding 

 their like ecological relationships, by their occupancy of different 

 territory. Within this state, however, they are apparently close 

 competitors, with the advantage, in point of numbers at least, 

 in favor of the yellow bass. 



Genus MORONE Mitchill 



Body rather short and deep, compressed; lower jaw scarcely projecting; 

 no supplemental maxillary; lower margin of preopercle simply serrate or 

 entire; base of tongue without teeth; dorsal fins more or less connected by 



