THE SPRING CANKER-WORM. 231 
been laid earlier in the season, in March and April, in patches on the 
hark of the trunk aud limbs. They may be soon found clustering on 
the terminal buds aud partly unfolded leaves, and are then about a line 
in length, and not much thicker than a bit of thick thread. Fortuuarely, 
owing to the want of wings, the female is exceedingly sedentary, aud 
year after year the apple and elm trees of particular orchards and towns 
are defoliated and turned brown, while adjoining orchards and towns 
scarcely suffer. By the 20th of June, in Essex County, Mass., the 
orchards or shade elms infested by them look as if a fire had run 
through them. At that date the worms are fully fed, and they then 
descend to the ground, letting themselves down by a silken thread. At 
this time I have destroyed thousands by jarring the tree and collecting 
those which fall down. I have watched old and young robins busily 
engaged in eating them, and from the number of toads in my garden, 
gathered under the trees, I feel confident that they eat multitudes of 
them. 
The worms at once enter the ground, change to chrysalids several 
inches below the surface, near the trunk of the tree, and there remain 
until the early days of March and April, when the wingless females as- 
cend the trees, and the winged males may be seen fluttering about. 
I took pains one spring, in the middle of April, to count the number 
of these moths on my apple trees, fourteen in number, averaging from 
six to seven inches in thickness, besides three elms. They were more 
abundant on the apple trees than on the elms. But on those seventeen 
trees there were counted, adhering mostly to the tarred paper, one thou- 
sand males and two hundred females. The spring of 1875 was cold and 
backward and few moths were seen before this date. From these data 
we can ascertain approximately the relative numerical proportions be- 
tween the sexes, which seems to approximate five males to one female. 
The species I have referred to is the spring moth, the Paleacrita ver- 
nata of Peck, but not of Harris. A. pometaria is much less abundant 
in the adult condition, aud only appears in the autumn. The wings are 
thicker than those of vernata, aud the caterpillar has an additional pair 
of prop-legs, though so short as to be useless. I find that most of the 
damage is done by the caterpillars of vernata. On June 15, 1875, I 
collected five hundred and fifty-seven caterpillars from the apple trees 
in my garden. Of these, five hundred aud twenty were vernata, and 
twenty-seven were the young of the autumn species. Peck, in his ac- 
count published in 1795, states that vernata does the principal damage.* 
Remedies. — The use of printer's ink laid on tarred paper is the cheap- 
est, though the ink should be applied every day or two. The use of tin 
troughs of oil surrounding the tree is almost sure to stop the ascent of 
the females, while wooden troughs of oil built around the bottom of the 
*It is probably this species which I have found feeding on the leaves May 30 and 
June 1, at Providence. It is a reddish-green obscurely striped larva, much like the 
canker-worm in form and size, but a little stouter. 
