Packard.] THE POPULATION OF AN APPLE TREE. 173 
in strong soap suds or a weak solution of coal oil or carbolic 
acid. 
The original home of this moth is the wild cherry. An¬ 
other closely allied species sometimes found on the apple, for 
which it deserts its favorite food-tree, the oak, is the Forest 
tent caterpillar. It differs from the other species in having 
a row of spots along the back instead of a< continuous line. 
The moth differs in the wings being more pointed at the 
apex, and in the transverse lines being rust brown. 
Not only do certain carnivorous beetles and a parasitic 
fly (Tachina) prey upon the caterpillar, but we have also 
found a small clialcid fly lurking under the mass of eggs, in 
which it was undoubtedly parasitic. 
The Canker Worm .— The traveller through eastern Mas¬ 
sachusetts, particularly in the neighborhood of Boston, is 
often struck during the early weeks of June by the desolate 
appearance of the orchards, which look as if a fire had passed 
through them. There is not a green thing on the trees, 
but all the branches are hung with a multitude of skeleton¬ 
ized leaves, rust}^, sere, and fluttering feebly in the breeze. 
This is not the work of fire, but an evidence of the industry 
of the canker worm. This scene has been repeated ever 
since the apple has been raised, or at least for a century, and 
is liable to be repeated for a hundred } r ears to come, unless 
a law is enacted to compel negligent farmers and gardeners 
to properly protect their trees. When the buds of the 
apple leaves are opening we shall on careful examination 
find a few little dark worms scarcely thicker than a horse¬ 
hair, nibbling the exposed edges of the opening leaves. 
Before people are aware of it these tiny caterpillars become 
nearly an inch long, and defoliate the tree. One can stand 
near the tree and hear the nibbling of thousands of little 
teeth. No one attempts to arrest the progress of the de¬ 
stroyers, and their advent is looked upon with dismay, min¬ 
gled, however, with a large proportion of fatalism. No one 
13 
