250 FISHES OF ILLINOIS 



evidently not afraid of mud, as is shown by its general distribution 

 over the lower glaciation of southern Illinois. 



While the warmouth and the rock bass avoid each other in great 

 measure by their strikingly different relations to water and bottom, 

 the former being a mud-loving fish and the latter found mainly in 

 clear rocky waters, the green sunfish avoids the other two by its 

 strong preference for the smaller streams, into which they enter 

 much less freely. The advantage of this avoidance of each other's 

 company is evident when we take into account the similar food 

 habits of these three species — all neglecting mollusks and crusta- 

 ceans and depending for food on fishes and insects. Owing, how- 

 ever, to their different ecological and local distribution, their coeffi- 

 cients of association are much below the average for their family — 

 1.17 for the rock bass and the warmouth, 1.51 for the rock bass and 

 the green sunfish, and 1.19 for the green sunfish and the warmouth — 

 or a general average of 1 . 29 for the group, to be compared with a 

 general family average of 1 .86. 



This sunfish is, according to our data, about twice as abundant in 

 southern Illinois as in either central or northern, our frequency ratio 

 for the first division being 1.5, and . 7 1 and . 78 for the other two. In 

 general range it is a fish of the Mississippi Valley, distributed from 

 the Great Lakes to Mexico, and occurring everywhere in small slug- 

 gish brooks. It is not reported from Canada and is not found east 

 of the Alleghanies. 



It is an excellent pan-fish, although small, weighing usually not 

 more than a quarter of a pound. It takes the hook readily with 

 worm bait, and is a sprightly little fighter for so small a species. The 

 food of the species, as illustrated by that of eight specimens, was 

 more than a third fishes, and the remainder insects and crawfishes. 



It was found by Mr. Surface spawning at Meredosia as late as 

 August 14, 1899. 



LEPOMIS ISCHYRUS (Jordan & Nelson) 



Jordan & Nelson, 1877, Bull. U. S. Nat. Mus., X, 25 (Lepiopomus). 



J. & G., 474; M. v., 117; B., I, 22 (' Apomotis cyanellus [part]); J. & E., I, 997 

 (Apomotis); N., 37 (Icthelis aquilensis); J., 45 (Lepiopomis) ; F., 68; L., 24 (Apo- 

 motis cyanellus); R., 27-32. 



Length 5 to 7 inches; robust and rather elongate, the back consider- 

 ably elevated, the form resembling that of Lepomis pallidus; depth J to 

 2 in length. Life colors not known; in spiritsdusky olive with mottlings 

 of orange and blue; faint blue bands on cheeks; dorsal and anal fins with 

 dusky spot on last rays; belly and lower fins coppery yellow. Head 2 . 6 

 to 2 . 7 in length, its top short and much flattened; profile conspicuously 



