Juday—Studies o?i Some Mountain Lakes. 789 
Sctlmo 
sebago. 
Salmo 
stomias. 
Solmo 
shastcu 
Small 
Salvel- 
inus 
f on tin- 
alis. 
Large 
S. fontin- 
alis. 
Fry. 
0.04 
26.55 
0.10 
36.84 
4.40 
1.48 
0.80 
0.46 
0.54 
Araneida (spiders!. 
Hydrachnidae (water-mites) 
Ephemerida .. 
22.61 
2.00 
Odonata. 
0.50 
Plecoptera... 
0.86 
1.55 
Orthoptera. 
6.55 
0.20 
0.12 
0.27 
3.80 
0.87 
0.16 
0.72 
1.18 
2.00 
3.75 
2.40 
Hemiptera. 
Nenroptera. 
Trichoptera. 
10.00 
2.11 
5.53 
0.11 
5.26 
15.31 
1.06 
1.57 
0.27 
0.06 
13.05 
8.83 
0.16 
9.20 
13.95 
2.80 
6.13 
3.46 
2.93 
1.17 
1.93 
7.75 
1.18 
31.70 
5.62 
0.38 
8.70 
7.47 
Lepidoptera .. 
0.69 
11.60 
7.60 
6.48 
0.17 
3.20 
14.40 
4.40 
Piptera . . 
Chironomus (larvae, pupae) 
SUmulium (larvae). 
Coleoptera. 
16.68 
1.52 
23.44 
16.90 
4^20 
5.40 
9.15 
31.10 
0.07 
Hymenoptera .. 
Insect fragments. 
48.10 
73.60 
Crustacea . 
Mol In sea.. 
Vegetable debris. 
0.34 
36.05 
2.47 
Sand and gravel . 
Of the twenty-two items which appear in the table, all ex¬ 
cept one (sand and gravel) may be regarded as sources of 
nourishment. While much of the vegetable debris had no 
food value and was probably taken very largely by accident, 
still in a- considerable number of cases it consisted of digesti¬ 
ble material and was present in such quantities as to indicate 
that it had been eaten purposely. 
It will be noted that there was considerable difference in the 
diet of the various species of trout. The landlocked salmon 
had partaken of 12 out of the 22 items of food; the green¬ 
back trout of 12; the rainbow trout 17; small brook trout 10; 
and large brook trout 16. These four species differed very 
widely also in the relative amoimt of fish consumed. The 
landlocked salmon had partaken most freely of this kind of 
food, fish remains constituting an average of more than a 
third of the stomach contents. The rainbow trout ranked 
second in this respect, while the brook trout had eaten most 
sparingly of this kind of food. All the fish remains that could 
be positively identified, however, w T ere found to be young suck¬ 
ers (Catostomus commersonii .) 
Insects played a very important role as an article of food. 
With the exception of the small brook trout and the fry, by far 
the greater part of the insect material found in the specimens 
