This insect feeds on a large list of shade trees as well as on fruit trees, the elms, willows, poplars and butternuts being, perhaps, the more favored food plants among the former group.

The moth is very variable in appearance, in northern New England greatly resembling that of the brown-tail moth, except that it has no brown tail. Further south the wings may bear numerous small, black spots. It flies during June, July and early August and lays its eggs, several hundred in a cluster, on the underside of a leaf. These eggs soon hatch and the caterpillars begin to spin a web, under which they feed. This web is extended as they grow and need more food, enclosing more of the leaves, until quite a part or all of a branch may be thus enclosed. After feeding thus for a month or more the caterpillars leave the web, and either in the ground or in crevices of the bark of the tree spin their cocoons. The moths may emerge from these cocoons the same year and lay eggs for a second generation, the caterpillars of which will feed the same fall, but in New England it is more usual for them to pass the winter in the cocoon, the moths appearing the following summer.

As the caterpillars of this insect feed together under a web, it is easy to cut off this and kill the caterpillars, particularly when the webs first appear and are small. Burning the webs on the tree is sometimes resorted to, but many of the caterpillars are liable to escape, and the tree is liable to be injured by this method. Spraying with arsenate of lead close around the webs, so that the leaves next to be enclosed shall have been poisoned, is also a good method of control. Numerous natural enemies of this insect aid man by holding it in check to some extent.