The Food of Fishes. 23 



the common perch, the white bass, and the croppie or 

 silver bass. 



The following account of the food of this suborder is 

 based upon the careful microscopic study of the contents 

 of four hundred and twenty-five stomachs, representing six 

 families, twenty genera * and thirty-three species. 



These were all collected by myself or one of my assist- 

 ants (Mr. W. H. Garman), and labeled at the time with 

 name of species, locality, and date. While the northern 

 half of the state is most fully represented, several trips to 

 southern Illinois contributed to the material studied, and 

 it is believed that the results arrived at are substantially 

 true for our whole area. 



Family ETHEOSTOMATID^. The Darters. 



What the humming-birds are in our avifauna, the "dart- 

 ers" are among our fresh-water fishes. Minute, agile, beau- 

 tiful, delighting in the clear, swift waters of rocky streams, 

 no group of fishes is more interesting to the collector ; and 

 in the present state of their classification, none will better 

 repay his study. Notwithstanding their trivial size, they 

 do not seem to be dwarfed so much as concentrated fishes 

 — each carrying in its little body all the activity, spirit, 

 grace, complexity of detail, and perfection of finish to be 

 found in a perch or a "wall-eyed pike," 



They are generally distributed, in suitable streams 

 througliout the state ; but we have found them much the 

 most abundant in northern Illinois, — in the upper Galena 

 River, in Yellow Creek near Freeport, and in tributaries of 

 the Kishwaukee at Belvidere. 



A short and strong minnow-seine of very fine mesh is 

 needed in collecting them. Rapid hauls, made almost on 

 the run, down stream, in swift and shallow water, will be 

 found the most successful. Two or three species, of wider 

 range, wnll be taken in ordinary situations, in collecting 

 for minnows generally ; but the brightest and most char- 

 acteristic forms can only be got by special effort, f 



*The classification of this paper is substantially that of Jordan's Man- 

 ual of the \'ertebrates of North America, etc., Ed. 2, 1878. 



tFor a very entertaining and instructive account of these fishes, the 

 reader is referred to papers in the American Naturalist, by Messrs. Jor- 

 dan and Copeland, Vol. X., pp. 335-341, and Vol. XI., pp. 86-88. 



