The larval hairs are irritating to some people and livestock and may cause a serious rash. The hairs are not normally considered poisonous. The cocoon is brownish gray and covered with hairs from the body of the larva. Cocoons usually are attached to foliage but may be found on tree trunks, rocks or other objects. The female, usually found in the vicinity of her pupal cocoon, has rudimentary wings and cannot fly.
Females normally are grayish with the tip of the abdomen much darker.
They have small thread-like antennae. Adult males are gray-brown to blackish moths with feathery antennae and a wing spread of approximately 1.2 inches. The forewings are rusty brown and the hind wings grayish brown. The egg mass, laid on the female pupal cocoon, contains about 300 white spherical eggs in several layers, all covered with a frothy substance intermixed with body hairs from the larvae. There is one generation per year.