166 College of Forestry 
No. 3(305) 84 mill. long. 
Crustacea. Hyalella knickerbockeri, 1...... 10 per cent. 
Alona, mamyas ti. tik. setae 
Cyclons sa wieWer. ee tee ae Or 
No. 4(305) 80 mill. long. 
Crustacea. (Oyclopss. 2 2 seein se eee 90 per cent. 
Plants. Algz and plant remains........... 10 per cent. 
No. 5(305) 78 mill. long. 
Crustacea. Alot in, estate Pet Saris i o« wawred 
(OMe Koy XO" Sebo o tod PO ORES Gat 
Plants. Alge and plant remains........... 10 per cent. 
No. 6(5) 98 mill. long. Mud and unicellular plants, small amount. 
No. 7(5) 105 mill. long. Mud and unicellular plants, small amount. 
No. 8(5) 100 mill. long. Mud and unicellular plants, small amount. 
No. 9(5) 95 mill. long. Mud and unicellular plants, small amount. 
No.10(5) 95 mill. long. Mud and unicellular plants, small amount. 
Nio.11(5) 110 mill. long. Stomach empty. 
90 per cent. 
90 per cent. 
In the juvenile stage the food is Crustacea, largely Ento- 
mostraca, the percentages of 4 specimens being: 
Mirdi and splantsy tscuseislam ive iit: pay cakessetioinets 17.50 per cent. 
PAID O isa rotons beets tore opstocste st boat Awe hg TREE yl 2.50 per cent. 
WNCOMOSETACR, <2. at tatces siete acl onev steers eteicver lone | 80.00 per cent. 
The change of food habits from crustaceans to mollusks 
and insects is noteworthy. 
Hankinson (1908, pp. 207, 245-251) examined 42 speci- 
mens from Walnut Lake, Mich., varying in size from 15 to 
19 inches (375-475 mill.) and hence all adult. Seven speci- 
mens containing food were caught in April and May 
and found to have eaten dragon-fly nymphs (386 in one 
individual), small bivalve mollusks, amphipods, and some 
marl. Twenty-seven specimens caught in August had eaten 
only midge larvee and the small entomostracan Daphnia. 
Hankinson remarks that “‘it is interesting to compare the 
food of the specimens taken in August with that of White- 
fish caught in the same haul of the net; the Whitefish were 
feeding upon Daphnia only, and apparently away from the 
bottom, while some of the suckers were feeding on midges 
at the bottom, and others on the Daphnia apparently above 
Tee 
