6 
The Regulative Action of Birds upon Insect Oscillations. 
lowing year. The food was wholly animal, neither fruit nor any 
other kind of vegetation having been taken by any of the birds. 
Only three of the above number had eaten canker-worms, which 
composed, as nearly as could be estimated, about one-fifth of the 
food of the entire group. Insects made ninety-three per 
cent., the remainder consisting of a common species of my- 
riapod (five per cent.), earth-worms, and gasteropod mol- 
lusks. Ants were eaten by these birds only in trivial 
numbers. Diptera, Orthoptera and spiders were conspicuous 
by their entire absence. Cut-worms were extraordinarily 
prominent in the food, making twenty-eight per cent, of the 
whole. Half of them consisted of a single large, injurious 
species ( JSTephelodes violans). Among the Coleoptera, which 
amounted to thirty-six per cent, of the whole, the Scar^baeidae 
and Elateridse were the principal elements, the former represented 
by eighteen per cent., and the latter by eleven. Among the Scar- 
abaeidas was a species known as a vine leaf-chafer ( Anomala 
binotatd), which made fourteen per cent, of the food. This in- 
sect was scarcely less abundant than the canker-worm, and 
appeared in extraordinary numbers in the food of nearly all the 
species of birds examined, although it had not attracted the atten- 
tion of the owner of the grounds. I searched a small vineyard ad- 
jacent, but saw no signs of unusual injury to the leaves. Carabidae, 
although common in the orchard, had scarcely been touched by 
the robins, only a single specimen of the family occurring. 
Hemiptera were found but in trivial numbers, representing about 
equally the families Coreidae and Cydnidae. Hymenoptera were 
still less abundant, composing only one per cent, of the food. 
Mimus carolinensis, L. Catbird. 
This species was very common, and thoroughly at home among 
the trees, where it was doubtless nesting. Fourteen specimens 
were taken, three at the first visit and eleven at the second. 
With the exception of two per cent, of myriapods, their food con- 
sisted entirely of insects. Canker-worms had been eaten by eight 
of the birds, but not in any great number, as they composed but fif- 
teen per cent, of the food of the species. A few cut- worms had 
been taken, and a larger number of other caterpillars, bringing 
the total for Lepidoptera up to about one-fourth of the food. 
