£8 
These were all collected by myself or one of my assistants (Mr. 
W. H. Garman), and labeled at the time with name of species, 
‘ocality and date. While the northern half of the State is most 
ully 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 ETHEOSTOMATIDA. The Darters. 
What the humming-birds are in our avifauna, the ‘“‘darters” are 
among our fresh-water fishes. Minute, agile, beautiful, delighting in 
the clear, swift waters of rocky streams, no group of fishes is more 
nteresting to the collector; and in the present state of their class- 
fication, none will better repay his study. Notwithstanding their 
irivial size, they do not seem to be dwarfed so much as concentrated 
fishes—each carrying in its little body all the activity, spirit, grace, 
230mplexity of detail and perfection of finish to be found in a perch 
or a ‘‘wall-eyed pike.” 
They are generally distributed, in suitable streams throughout the 
State; but we have found them much the most abundant in North- 
arn [llinois,—in the upper Galena river, in Yellow creek near Free- 
port, 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, will be taken in ordinary situations, 
in collecting for minnows cenerally : but the brightest and most 
gharacteristic forms can only be got by special effort.* 
I shall give here a description of the food of the family, based 
upon the study of -the contents of seventy stomachs representing 
fifteen species, collected in all parts of Illinois, in several months of 
four successive years. These indicate much more than their num- 
ber woul! imply, since from those collected at each time and place 
as many were commonly studied as were necessary to give a full 
idea of the food of the species then and there. ‘lhe different indi- 
Viduals from the same date and locality usually agreed so closely in 
food. that the study of from two to five gave all the facts obtain- 
able from several times as many. ‘The data here given, therefore, 
really exhibit the food of the family at different seasons in twenty- 
Mine localiiies within the State. 
The genus Pleurolepis is comparatively rare in Illinois, as_ there 
are few of the sandy streams in the State, which it inhabits. 
Beven individuals were examined—four of P. pellucudus and three 
of P. asprellus. The food of these specimens was remarkably 
unifoim—the only elements found being the larve of small diptera 
and ephemerids. Highty-one per cent. of the food of all consisted 
*Pora yverv eatertaining and instruetive account of these fishes, the reader is referred 
tO paner-s i> tle er ‘rican Naturalist, by Messrs. Jordan and Copeland, Vol. X, pp. 335-3841. 
and Vol. XI, bP, . 85-88. 
