HABITS OF YELLOW PERCH. 311 
its period of greatest abundance (adult midges, midge pupz), but in other cases there 
was no such correlation. In the autumn the number of cladocerans in Lake Mendota 
increased (Birge, 1897), and the quantity eaten by perch also increased, but during the 
vernal cladoceran increase the opposite was true. Although copepods rivaled cladocerans 
in abundance at certain seasons they were never eaten in large quantities, probably 
because they are active, small, and do not collect in swarms to any extent, as 
cladocerans do. : 
The following list gives the number of perch out of the 1,147 examined which ate 
each constituent of the food; the percentage of the total which each constituent formed 
when it was 1 per cent or more; and the occurrence of the constituents throughout the 
year. All figures in parentheses mean percentage of total food by volume; figures 
outside parentheses indicate the number of fish eating each food. 
INSECT LARVA—Continued. 
Diptera larvee—Continued. 
Fisu (4.5), all year: 
Fish eggs— 
Unidentified, 2, April. 
Cisco eggs, 1, November. 
Perch eggs, 4, April. 
Sucker eggs, 4, May. 
Fish remains— 
Unidentified remains (3.9), 85, March to 
November. 
Abramis chrysoleucas, 1, October. 
Eucalia inconstans, 1, February. 
Lepomis incisor, 6, January, February. 
Notropis heterodon, 1, February. 
INSECT LARVA (38.3), all year: 
Diptera larve (32.7)— 
Unidentified chironomid larve (5), 148, 
all year. 
Chironomus abbreviatus, 10, May to Sep- 
tember. 
. decorus (8.3), 288, all year. 
. fulviventris (1.7), 86, all year. 
. lobiferus, 62, all year. 
- modestus, 3, April. 
. tentans (2), 28, October to February. 
. viridicollis, 7, October, December. 
. viridis, 1, August. 
. sp. 82 Johannsen, 1, May. 
. sp. 83 Johannsen, 3, May. 
Corethra punctipennis (5.6), 329, all year. 
Cricotopus trifasciatus, 7, April, May. 
Orthocladius sp., 3, July, March. 
O. nivoriundus, 2, July. 
Palpomyia longipennis, 6, May, July. 
Probezzia glaber, 12, April to July. 
Probezzia pallida, 14, April to July. 
Procladius sp., 29, March. 
Protenthes choreus (3), 166, all year. 
P. culiciformis, 2, August. 
Stratiomyia sp., 1, June. 
Tanypus sp., 37, all year. 
Qa000 
aq0aaon 
T. carneus, 7, April, May. 
T. decoloratus, 6, April, May. 
T. monilis, 20, July, November. 
Tanytarsus dives, 15, March to May. 
Tanytarsus sp., 2, March. 
Ephemerid nymphs (1)— 
Mayfly sp., 32, all year. 
Betisca sp., 22, March to May. 
Cznis diminuta, 9, May to September. 
Callibetis sp., 18, April to May. 
Ecdyurus maculipennis, 1, June. 
Ephemerid sp., 14, May, June. 
Heptagenia interpunctata, 1, June. 
Siphlurus sp., 1, May. 
Odonata nymphs (1.4)— 
Damselfly sp., 34, all year. 
Argia sp., 1, May. 
Enallagma antennatum, 19, May to July. 
E. hageni, 28, March to July. 
E. pollutum, 6, May. 
Ischnura verticalis, 9, March to June. 
Dragonfly sp., 7, November to July. 
Anax junius, 2, March, July. 
Libellula sp., 1, April. 
Nehalenna irene, 1, April. 
Sympetrum, 3, October. 
Trichoptera larve (1.5)— 
Agraylea multipunctata, 10, June, July. 
Hydroptila, 3, June, August. 
Leptocella uwarowii, 17, March to Sep- 
tember. 
Leptocerus sp., 5, June to November. 
Leptocerus dilutus, 7, May, August. 
Molanna uniophila, 5, July, August. 
Orthotrichia, 1, October. 
Platyphylax subfasciatus, 2, May, August. 
Neuroptera larve (1.7)— 
Sialis infumata (1.7), 75, all year. 
