250 FISHES OF 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 crustaceans and depending for food on 

 fishes and insects. Owing, however, to their different ecological 

 and local distribution, their coefficients 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 abun- 

 dant in southern Illinois as in either central or northern, our 

 frequency ratio for the first division being 1.5, and .71 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 occur- 

 ring everywhere in small sluggish 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 considerably 

 elevated, the form resembling that of Lepomis pallidus; depth }/g to 2 in 

 length. Life colors not known; in spirits dusky 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 angled above eye; eye 



