The caterpillars of this insect feed on birch. Oak is a preferred host of the gypsy moth, and solid stands of oak are subject to periodic defoliation. Some have a light narrow stripe along the back and all have two rows of tubercles bearing hairs. From the head, the first five pairs are blue, and the remaining six pairs are brick red. They feed during May and June, and do most of their feeding at night.
Caterpillars pupate in cracks or crevices spinning a very small amount of silk.
The moths emerge in about 2 weeks. The female is buff with narrow zigzag lines across the forewings. The males fly freely. Eggs are laid on the bark of trees, on stones, or lumber. They are laid in masses of about 400 eggs and are covered with buff hairs from the body of the females.