The Relation of Mollusks to Fish in Oneida Lake — 185 
The species of mollusks noted in the food are as follows: 
Amnicola, taken in May, July and August. 
Valvata tricarinata, taken in May. 
Planorbis, taken in May. 
Physa (young). 
Anodonta (young). 
Hankinson (1908, p. 213, 245-250) records the food of 
22 individuals (adults). Of these, 8 had eaten midge larva, 
5, caddis-fly larve, 1, an amphipod, 7, Heptagenia larve, 9, 
Hexagenia larvee, 5, leeches, 3, dragon-fly larvee, 3, May-fly 
larvee, and, 4, crawfishes. From this data the sunfish in Wal- 
nut Lake prefer insect larve, principally Hexagenia and 
Heptagenta. Hankinson says “ while May-fly larvee of the 
genera Hexagema and Heptagenia seemed to be the favorite 
food, crawfish, amphipod crustaceans, snails, leeches, midge 
larvee, caddice-worms, and other insects were all found in 
the contents.” 
J. E. Reighard (1915, p. 233-234) examined 13 speci- 
mens from Douglas Lake, Mich., 9 of which contained food. 
In 6, mollusks or their fragments were found, 4 of these 
containing nothing else, while a fifth contained 3 small 
snails, fragments, and a quantity of orange colored fruits of 
Chara; 4 had eaten insect larvee and 1 an ostracod. Reighard 
says “‘ snails appear to be the most important element of the 
food and next to these, insect larvee, but exact percentages are 
not available.” Two species of mollusks were identified from 
the stomach contents, Amnicola limosa, adult, and Planorbis 
bicarinatus portagensts (== P. antrosus portagensis). Mar- 
shall and Gilbert (1905, p. 519) examined 5 specimens, from 
Lake Mendota, Wis., and found the food to consist of insect 
larvee, snails, and small bivalves. 
Seventeen specimens were examined from Oneida Lake, 
13 of which contained food. The food ratios based on the 
data in the following pages, are: 
‘Adult. Youth. Infancy. 
IVIOUINESGA cea cts sole, oo he ee 66.25 67 .50 — 
Grustaces. * 02232 See eee 5 16.50 90.00 
tsecta- > .tVPi oe Ser ee eee 6.25 75 — 
IG OZOGeR ete le ote ens nena ene .25 5.00 
NR ee poets eh ada Oe 15.00 5.00 
1.25 
Macerated material ......... AED AS — 
