400 Wisconsin Academy of Sciences, Arts, and Letters. 
G. Order Hymenoptera. 
Several parasites have been caught or bred from insects ob¬ 
tained from the lake. With the exception of Diapria colum- 
bana Ashmead (kindly determined by Prof. C. T. Brues) they 
still await identification. 
As an extraneous source of food supply the Hymenoptera 
are not without some importance in the lake economy. The 
variable winds of the summer blow thousands of insects of all 
sorts into the lake, where they become water-trapped and 
drown, or may be directly eaten by fish. As regards drown¬ 
ing I estimated in the summer of 1914 that 2 % of the bulk of 
insects collected was formed by dead insects,—most of them 
Hymenoptera. At the time of their summer flights millions 
of winged ants are blown into the lake and become the toll of 
the water and of the fish. That the latter will eat ants greed¬ 
ily, is attested by the gorged stomachs of perch and other fish 
which were filled with Camponotus, and Formica. Other 
forms which are very common in the lake toll but rarer in fish 
stomachs are Pelecinus polyturetur. Apis mellifica, various 
species of Bombus, Polistes, Yespa, Bembex, Ammophila, Pom- 
pilus. Ichneumon, etc. 
The important fact, however, is that the fish should eat 
ants in such quantities w^henever available, since this brings up 
the question of nauseous emanations, similar to those by which 
the Hemiptera are supposedly protected. 
H. Order Lepidoptera. 
Two species of Lepidoptera have been taken in the lake. ~ 
Nymphula maculalis larvae were secured in different parts of 
the lake in various depths. But the optimal situation seems 
to be the sheltered portion of University Bay, at the point 
where the bar joins the Picnic Point peninsula. There the lar¬ 
vae of N. maculalis and N. allionalis occur in large numbers 
on Potamogeton and Yallisneria. In Picnic Pond close by 
Hydrocamp a sp. is also abundant. 
As an item of fish food the Lepidoptera are negligible. 
I. Order Trichoptera (Table 5, p. 475 
During the latter half of summer and early fall the Trichop¬ 
tera form the greater bulk of the littoral fauna of Lake Men- 
