258 FISHES OF ILLINOIS 



palatines; lower pharyngeals narrow and weak, the teeth slender and sharp; 

 operculum more or less prolonged backward in adults, always rather wide 

 and bluntly rounded posteriorly, usually rather Conspicuously striate lon- 

 gitudinally, the membranous margin very narrow or wholly wanting, its color 

 when present very little if any lighter than the black of the osseous portion 

 of the flap; gill-rakers rather long and slender, but firm, the longest almost 

 1/^ diameter of eye. Dorsal X, 10 to 12, usually X, 11; spines long, the 

 longest 1.3 to 2.4 in head, usually about 2 in adults; anal III, 10 or 12; pec- 

 torals long, pointed behind, about equal to head or a little less, .9 to 1 in 

 head, usually about 1 in adults; ventrals reaching anal. Scales 6, 38-48, 

 13 or 14; those on cheek in 5 rows. 



This is the principal sunfish of our larger rivers, and the one 

 appearing most frequently in the large nets of the regular river 

 fishermen. It occurs throughout the state, but is generally 

 limited to the larger streams and their principal tributaries, 

 except that it is common in the northeastern glacial lakes. It 

 has also been taken by us in the Michigan drainage. Judging 

 from our 214 collections, it is primarily a pond species, its fre- 

 quency ratio in the ponds and lakes being 1.6. In flowing 

 streams it is commonest in the larger rivers, and least com- 

 mon in creeks. 



Along the Atlantic coast it is found from New Jersey to the 

 Florida peninsula; in the Great Lakes, from Ontario westward, 

 ranging thence to the south and west through the Ohio and the 

 lower Missouri basins to New Orleans and Texas. 



It is said by Jordan and Evermann to be perhaps the best 

 known and certainly the most important of all our true sun- 

 fishes, decidedly a lake species everywhere, but more abundant 

 in the smaller lakes. It is the largest of our sunfishes, reaching 

 a length of twelve to twenty-four inches and a weight of nearly a 

 pound, the maximum weight being about a pound and a half. 



In the food of twenty-six specimens we have found a trace of 

 fishes — a single darter eaten by one — a moderate percentage of 

 univalve mollusks, a large ratio of insects (45 per cent.), and 

 many of the medium-sized Crustacea. The insect food is derived 

 in great measure from larger aquatic larvae than most of our 

 sunfishes feed upon. The stomachs of some of our specimens 

 were found to contain as much as 24 per cent, of aquatic vege- 

 taton — too large a quantity to have been swallowed accidentally 

 with the animals eaten. Its food differs in detail, however, 

 according to the situation in which it is found. 



The bluegill moves in schools, and may be caught with 

 almost any kind of bait or tackle. Its flesh is firm and flaky, 



