The Regulative Action of Birds upon Insect Oscillations. 5 
of having been ruined by fire. Closer • examination of the trees 
most affected showed that the branches, stripped of every vestige 
of green, were festooned with the webbing left by the worms. 
To the webs the withered remnants of the leaves adhered as they 
fell, the very petioles having been gnawed off at the twigs. Not 
one per cent, of the trees were uninjured, and these were invaria- 
bly on the outer part of the orchard. Those which had been 
attacked several years in succession were killed; and there was a 
large area in the midst of the orchard from which such trees had 
been removed. One did not need to enter the enclosure to learn 
that the birds were present in extraordinary numbers and variety. 
From every part of it arose a chorus of song more varied than I had 
ever heard in any similar area at that season of the year. Most of 
the common summer residents were found there ; and upon a second 
visit in 1882 many of the migrant species likewise occurred. The 
first collection was made on the 24th of May, 1881, and the 
second on the 20th of the same month im the following year. 
The season was less advanced at the time of the second collection 
than at the first, so that the actual difference between the two was 
probably not less than two weeks. At the first visit fifty-four 
birds were taken, representing twenty-four species, and seven other 
species w T ere noted in the orchard of which no specimens were 
obtained. On the second visit ninety-two birds were shot, repre- 
senting thirty-one species, and four other species were seen. In 
1881 the worms were nearly all fully grown, and many of them 
had already entered the ground for their transformation, so that 
the larvae were less abundant than they had been earlier. In 1882 
most of them were about half-grown, onlv a few having reached 
adult size. They were distinguishable with difficulty upon the 
leaves of the trees; but when a large branch was shaken or jarred, 
from a dozen to twenty would expose themselves by spinning 
down and hanging at the end of a thread. The owner of the 
orchard informed me that they were about twice as abundant the 
preceding season. 
TURDID^E. Thrushes. 
Turdus migratorius, L. Robin. 
This species was abundant and nesting in the orchard. Nine 
specimens were obtained in all, three in 1881 and six in the fol- 
