FOOD OF THE SHORE FISHES OF CERTAIN WISCONSIN LAKES. 269 



Perca flavescens (Mitchill). Yellow perch, ring perch, American perch. 



Data for I Qi 4 (Feaxse, i()is)- — Number examined, 16. Average length : 92.5. Food: Insect larvae, 

 19.5; adult insects, 2.7; mites, 0.5; Hyalella, 32.8; ostracods, 0.3; copepods, 0.2; cladocerans, 36.6. 



Station 6; June 24, 1915; number examined, 10. Length: Maximum, 127; minimum, 76; average, 



111. 4. Food: Fish eggs, 3; Chironomus plumosus larvae, 0.3; C. lobiferus larvse, 2.5; Orthocladius 

 larvae, 8; Cricotopus trifasciatus larvs, 1.5; Probezzia larvae, 1.2; Enallagma antennatum nymphs, 0.5; 

 Caenis diminuta larvae, 4.1; Heliopsyche borealis larvae, 5.1; Leptocella uvvarowii larvae, 11; Agraylea 

 larvae, o.i; Cricotopus trifasciatus pupae, 0.4; Chironomus pupae, 0.2; C. lobiferus pupae, i; mites, 0.2; 

 Hyalella, 40.6; Planorbis, 0.8; Sphaeridae, 0.8; oligochaetes, 3; seeds, o.i; plant remains, 2.5; fine debris, 7. 



Summary. — Food: Insect larva, 43.3; pupae, 1.6; mites, 0.2; amphipods, 40.6; snails, 0.8; clams, 

 0.8; oligochaetes, 3; plants, 2.6; d6bris, 7. 



Station 5; August 18; number examined, 2. Lengths: 135, 113. 5. Food; Caenis diminuta larvae, 

 10; Baetisca larvae, 5; Chironomus adult, 2.5; Corixa adults, 51.5; Hyalella, 30.7; Arcella, 0.1; filamentous 

 algae, 0.3. 



Summary. — Food: Insect larvae, 15; adult insects, 54; amphipods, 30.7; protozoans, 0.1; filamentous 

 alga, 0.3. 



Station 15; August 21; number examined, 2. Lengths: 138, 132. Food: Daphnia longispina hya- 

 lina, 100, 



Station 17; August 23; number examined, 10. Length: Maximum, 187; minimum, 123; average, 



156.5. Food: Tadpoles, 3.5; Chironomus digitatus larvae, i.i; C. tentans larvae, 2.5; C. modestus larvae, 

 i; Palpomyia longipennis larvae, 0.2; Aeschna umbrosa nymphs, 12; Enallagma hageni nymphs, 9.6; 

 Celithemis eponina nymphs, 1.8; Caenis diminuta nymphs, 3.4; Baetisca nymphs, 25.6; neuropteron 

 larvse, 2.2; Chironomus digitatus pupae, 2.4; Gryllus nymphs, 0.1; Corixa adults, 4; Dytiscid beetle, 

 0.3; Naucoris adult, 0.1; Scirtes adult, 0.2; Hyalella, 8.3; ostracods, 0.1; Cyclops, +; Eurycercus, 0.1; 

 Planorbis, 2.2; Physa, 17. i; Arcella, 0.1; fine debris, i. 



Summary. — Food: Insect larvae, 63.9; pupa, 2.6; adult insects, 4.6; amphipods, 8.3; ostracods, 

 0.1; cladocerans, 0.1; snails, 19.3; protozoans, 0.1; debris, i. 



Station 18; August 18; number examined, 3. Lengths of each : 100. Food: Chironomus lobiferus 

 larva, i.i; C. digitatus larva, 1.2; Probezzia larva, 0.3; Batisca nymphs, 1.3; Chironomus digitatus 

 pupa, 2; TrJanodes flavescens adults, i; mites, 1.6; Hyalella, 90.8; Cyclops, 0.1; filamentous alga, 0.3. 



Summary. — Food: Insect larva, 3.9; pupa, 2; adult insects, i; mites, 1.6; amphipods, 90.8; cope- 

 pods, 0.1; alga, 0.3. 



Station 18; September 22; number examined, 2. Lengths: 146, 180. Food: Fish, 80; Hyalella, 

 17.5; Myriophyllum, 5. 



Station 15; October 2; number examined, I. Length: 124. Food: Daphnia longispina hyalina, 

 95; D. pulex, 5. 



Station 29; October 11; number examined, 2. Lengths: 63.5,63.5. Food: Chironomus lobiferus 

 larva, 15.5; C. decorus larva, 25; Enallagma antennatum nymph, 40; ostracods, i; Cyclops, 2.5; Daphnia 

 pulex, 7.5; oligochates, 7.5; diatoms, i. 



Summary. — Food: Insect larva, 80.5; ostracods, i; copepods, 2.5; cladocerans, 7.5; oligochates, 

 7.5; alga, I. 



Station 26; December 4; number examined, 8. Length: Maximum, 280; minimum, 245; average, 

 265. Food: Fish, 10; Chironomus decorus larva, 84; Sialis larva, 5.6. 



Station 28; May 30, 1916; number examined, 5. Length: Maximum, 229; minimum, 160; average, 

 186. Food: Fish eggs, 0.2; Chironomus lobiferus larva, 5.4; C. sp. larva, 3.2; Enallagma hageni nymphs, 

 16.4; Atax txu-gidus nymphs, i; Corixa sp. nymphs, 17.6; Chironomus sp. pupa, 7; Hyalella, 15.6; ostra- 

 cods, 0.2; Physa, 4; filamentous alga, 11. 6; plant remains, 3; mud, 7.6; ddbris, 3. 



Summary. — Food: Fish eggs, 0.2; insect larva, 43.6; insect pupa, 7; amphipods, 15.6; ostracods, 

 0.2; MoUusca, 4; alga, 11. 6; plants, 3; debris, 10.6. 



Station in Oconomowoc Lake; June 14; number examined, 13. Length: Maximum, 67; minimum, 

 54; average, 57.8. Food: Chironomus sp. larva, 8.4; Probezzia glaber larva, 3.4; Procladius sp. larva, 

 0.3; Enallagma antennatum nymphs, 7; Chironomus sp. pupa, 4.7; Hyalella, 18.7; ostracods, 0.3; Cyclops, 

 32.7; Daphnia, 18.8; Chydorus spharicus, 2.3; Eurycercus, 0.5; Physa, 0.6; filamentous alga, 1.4. 



Summary. — Food: Insect larva, 19. i; insect pupa, 4.7; amphipods, 18.7; entomostracans, 54.6; 

 MoUusca, 0.6; alga, 1.4. 



69571°— 18- — 18 



