84 
The Food of the Smaller Fresh - Water Fishes. 
Hybopsis stramineus, Cope. Straw-colored Minnow. 
This insignificant species has been found by us in rivers and 
small streams throughout the State. 
The gill-rakers were few and short. 
Only five specimens were studied, all from rivers in Central 
Illinois. About three-fourths of their food consisted of animal 
matter, nearly all neuropterous larvae (fifty-eight per cent.), 
Ephemeridae standing at forty-eight per cent., and case-worms at 
ten. Crustacea were ten per cent., all Cyclops except a trace of 
Canthocamptus. About one-fourth of the food was vegetation, 
chiefly seeds of grasses, occurring, of course, only accidentally in 
the water. Two had derived from ninety to one hundred per cent, 
of their food from ephemerid larvae, and four of the five had eaten 
vegetation amounting to as much as eighty per cent. 
Luxilus cornutus, Raf. Shiner. 
This large and fine minnow is probably the commonest fish in 
Illinois, occurring in lakes and streams of all sizes everywhere 
throughout our limits. 
The gill-rakers are short and few, and of insignificant develop- 
ment, and the intestine is shorter than the head and body. 
Twenty-one specimens were studied, from all parts of the 
State and at various seasons of the year. Animal food amounted 
to two-thirds of the whole, fourteen per cent, being fishes, eaten, 
however, by only one of the specimens. Insects, eaten by 
nineteen, were reckoned at forty-five per cent., only one-fourth of 
them terrestrial. Gyrinid larvae, Corixa, and larvae of Falingenia 
hilineata were among the forms recognized. The crustacean 
ratio was insignificant, standing at only three per cent., all the 
abundant amphipod, Allorchestes dentata, with the exception of 
traces of a considerable variety of Entomostraca, including 
Chydorus, Acroperus leucocephalus , and Cypris. One of the 
water-worms (Lumbriculus) was noticed in a single specimen. 
Vegetable food was reckoned at thirty-eight per cent., only about 
one-third of it consisting of Algae, and the rest of accidental 
fragments, including the seeds, anthers, and pollen of plants, with 
a little Potamogeton and various forms of fungus spores. One of 
the commonest of the Algae was Cladophora glomerataf' taken 
*Kindly determined for me by Rev. Francis Wolle, Bethlehem, Pa. 
