Tack^vrd.] the POPULATIOISr 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 chalcid fly lurking under the mass of eggs, in 

 which it was undoubtedly parasitic. 



TJie 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, rusty, 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 years 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 hoar the nibbling of thousands of little 

 teeth. No one attempts to arrest tlic progress of the de- 

 stro^'ers, and their advent is looked upon with disma}', min- 

 gled, however, with a large proportion of fatalism. No one 



13 



