190 College of Forestry 
rivers and found these had eaten 6 per cent. fish, 20 per cent. 
thin-shelled mollusks, 25 per cent. insect larvee and about 49 
per cent. Crustacea. A dozen specimens from Lake Michi- 
gan had eaten nothing but fishes and crawfishes, the former 
greatly predominating. The Perch is said to eat the spawn 
of other fishes. Forbes (1880, a, pp. 28-31) examined 49 
individuals of all ages, finding the food to vary for the dif- 
ferent ages, as noted below: 
Inrancy. Less than 25 mill. long. 2 specimens examined. 
Cyclops and 
Entomostraca. About equal quantity of 
Daphnia, 
Insecta. A few minute Chironomus larve. 
YoutH. 27-50 mill. long. 9 specimens examined. 
Crustacea. Cladocera, Daphnia. 
Simocephalus. 
Bosmina. 
Chydorus. 
Pleuroxus., 
Copepoda. Cyclops. 
Diaptomus. 
Amphipoda. Allorchestes.... .. 
Insecta. Chironomus larve. 
Ooriza. 
Dphemerid@o. & «a. Mi. Os 
66 per cent. 
34 per cent. 
Youtu. 63 mill. long. 4 specimens examined, from. Peoria, IIl., in 
November. 
Insecta. Hemiptera, Comea .s.. -cl ese 
Neuroptera, Palingenia larve ...... 
Odonata, Agrionide nymphs ....... 
YOUTH. 88-100 mill. long. 4 specimens examined. 
Insecta. Chiefly nymphs of May-flies ........ 
Crustacea. Chiefly Amphipoda and Cladocera. 
ADULT. 18 specimens examined from Illinois streams. 
Crustacea. Cambarus. . \ 10 t 
Palemonetes. . . { BST book 
Allorchestes.... 15 per cent. 
Aseitus.. ...\420%e 
Mancasellus. . ... § SOG NES ges 
Insecta. Ephemeridi) . oo 7% oe = eta i hie ) 
Odemates pai 0s. eae Ae sabes ‘ 
BRT ye ANCE: Pt che- cere ah J 
12 per cent. 
83 per cent. 
5 per cent. 
45 per cent. 
55 per cent. 
48 per cent. 
24 per cent 
