320 FISHES OF ILLINOIS 



dant with us in the central part of the state (1.7), about half as 

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

 mon in southern Illinois. 



It is a fish of the lakes and deeper rivers from New Brunswick, 

 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 Mississippi 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 importance, 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 disappeared. 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 larva? 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 (Ccntrarchidcc) 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 terri- 

 tory. Within this state, however, they are apparently close com- 

 petitors, 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 project- 

 ing ; no supplemental maxillary; lower margin of preopercle simply ser- 

 rate or entire ; base ol tongue withoul teeth; dorsal tins more or less con 

 nected l>v membrane; anal spines.-!, not graduated; scales ctenoid. Two 



