HABITS OF YELLOW PERCH. 317 
JULY 1, 1915. 
Depth, 18.3 m.; number examined, 9. Food—Chironomus decorus larve, 21 per cent; Protenthes 
choreus larve, 12.4 per cent; Corethra punctipennis larve, 15 per cent; Chironomus decorus pupe, 
21.6 per cent; Corethra punctipennis pup, 0.5 per cent; mites, o.1 per cent; ostracods, o.r per 
cent; Daphnia hyalina, 13.3 per cent; Corneocyclas idahoensis, 8.3 per cent; Hyalella, 0.5 per cent; 
Gordius (from chironomid larvae), 6.4 per cent. 
Summary.—Midge larve, 48.4 per cent; midge pupz, 22.1 per cent; mites, 0.1 per cent; 
ostracods, 0.1 per cent; cladocerans, 13.3 per cent; clams, 8.3 per cent; amphipods, 0.5 per cent; 
Gordiacea, 6.4 per cent. 
Depth, 15 m.; number examined, 5. Food—Chironomus decorus larve, 14 per cent; Corethra puncti- 
pennis larve, 9.4 per cent; Protenthes choreus larve, 6 per cent; Chironomus decorus pupe, 33 pet 
cent; Protenthes choreus pupe, 7.6 per cent; Daphnia hyalina, to per cent; Sphaeriide, 14 per cent; 
Gordius, 4 per cent. 
Summary.—Insect larvee, 29.4 per cent; insect pup, 40.6 per cent; cladocerans, 10 per cent; 
clams, 14 per cent; Gordiacea, 4 per cent. 4 
Depth, 4 m.; number examined, 5. Food—Minnows, 19.4 per cent; Chironomus unidentified larve, 
5-6 per cent; Chironomus abbreviatus larve, 1 per cent; Corethra punctipennis larve, 2 per cent; 
Chironomus decorus pup, 1 per cent; Cambarus propinquus, 36 per cent; Hyalella, 9 per cent; 
Eurycercus lamellatus, t per cent; Physa heterostropha, 16 per cent; Planorbis, 0.4 per cent; leech, 
9 per cent. 
Summary.—Fish, 19.4 per cent; midge larve, 8.6 per cent; midge pupz, 1 per cent; cray- 
fishes, 36 per cent; amphipods, 9 per cent; cladocerans, 1 per cent; snails, 16.4 per cent; leech, 
9 per cent. 
MAY 12, 1916. 
Depth, o.5 m.; number examined, 5. Food—Sucker eggs, 21.8 per cent; Chironomus decorus larve, 
I per cent; C. fulviventris larve, 1.6 per cent; Enallagma antennatum nymphs, 3 per cent; Argia 
nymph, r per cent; Leptocerus ancylus larve, 8 per cent; Sialis infumata larve, 16.9 per cent; 
Hyalella azteca, 0.8 per cent; Physa heterostropha, 8 per cent; Nephelopsis obscura, 19 per cent; bud 
scale, 0.4 per cent; Lemna, 1.5 per cent; filamentous alge, 2 per cent; sand, 13 per cent; débris, 
2 per cent. 
Summary.—Fish eggs, 21.8 per cent; insect larve, 31.5 per cent; amphipods, 0.8 per cent; 
snails, 8 per cent; leeches, 19 per cent; plants, 3.9 per cent; sand, 13 per cent; débris, 2 per cent. 
Depth, 4 m.; number examined, 2. Food—Perch eggs, 99.7 per cent; Chironomus decorus larve, 0.1 
per cent; Sialis infumata larve, o.1 per cent. 
Depth, 7 m.; number examined, 3. Food—Chironomus decorus larve, 51.6 per cent; Protenthes choreus 
larve, 21.7 per cent; Corethra punctipennis larve, 4.7 per cent; Sialis infumata larve, 15 per cent; 
Ammnicola limosa, 1.3 per cent; leech, 5 per cent; fine mud, o.7 per cent. 
Summary.—Insect larve, 93 per cent; snails, 1.3 per cent; leeches, 5 per cent; mud, 0.7 per 
cent. 
Depth, 15 m.; number examined, 3. Food—Chironomus decorus larve, 8.3 per cent; Protenthes choreus 
larve, 8.3 per cent; Corethra punctipennis larve, 2 per cent; Leptocerus ancylus larve, 1.3 per cent; 
Sialis infumata larve, 5 per cent; oligochetes, 28.3 per cent; bottom mud, 46.7 per cent. 
Summary.—insect larve, 24.9 per cent; oligochetes, 28.3 per cent; bottom mud, 46.7 per cent. 
Depth, 17 m.; number examined, 3. Food—Chironomus decorus larve, 18.7 per cent; Protenthes 
choreus larve, 8.7 per cent; Corethra punctipennis larve, 1 per cent; oligochetes, 46.7 per cent; 
Corneocyclas idahoensis, 0.7 per cent; bottom mud, 24.3 per cent. 
Summary.—Insect larve, 28.4 per cent; oligochetes, 46.7 per cent; clams, o.7 per cent; mud, 
24.3 per cent. 
Except for the food of a few young perch and for the comparison (p. 319) between the 
examinations in Lakes Wingra and Mendota, no particular studies have been made of 
the perch from different lakes. It is probable that the feeding habits are rather uniform, 
but the food varies according to conditions in different localities. 
