The Regulative Action of Birds upon Insect Oscillations. 9 
birds had eaten Psenocerus supernotatus , amounting to four per 
cent, of the food, and the other Coleoptera were scattered through 
the families Carabidae, Nitidulidae, Scarabaeidae, Elateridae and 
Calandridae. The Hemiptera were represented by trivial numbers 
of four families, including a few chinch bugs. 
MNIOTILTIDiE. Warblers. 
Helminthophaga peregrina, Wils. Tennessee Warbler. 
A single specimen of this little warbler was taken in 1882. 
Four-fifths of its food consisted of canker-worms, and all the 
remainder of a single species of beetle ( Telephorus hilineatus ). 
Dendrceca ^estiva, Gmel. Summer Yellow Bird. 
This bird, common every where at this season, was also abund- 
ant in the orchard. Five specimens were shot in all. The food 
was insects, excepting six per cent, of spiders. Two-thirds of 
the total amount eaten by all of the birds consisted of canker- 
worms. Coleoptera were twenty-three per cent, of the whole 
amount, six per cent, being Aphodius, and twelve per cent. 
Psenocerus supernotatus , already frequently mentioned. Carab- 
idae and Calandridae were represented by insignificant ratios, and 
Lampyridae by a single Telephorus eaten by one of the birds. 
One per cent, of Hemiptera, and two of Hymenoptera complete 
the record. 
Dendrceca Pennsylvania, L. Chestnut-sided Warbler. 
Two specimens of this abundant migrant were shot in the 
orchard in 1882. Like the preceding warbler, two-thirds of their 
food consisted of canker-worms, and an additional ten per cent, 
of other caterpillars. A few ants were eaten by both of the birds. 
Eleven per cent, of Coleoptera, likewise eaten by the two, was 
about equally divided between some undetermined Scarabaeidae 
and Psenocerus supernotatus. One of the birds had eaten plant- 
lice, which amounted to five per cent, of the food; and both had 
taken ants to the amount of six per cent. 
Dendrceca striata, Forst. Black-poll Warbler. 
Four of these birds were shot in 1882. Some undetermined 
seeds found in the crop of one of them reduced the insect ratio 
