The caterpillar is very common especially in late summer in eastern North America, extending as far west as Texas, California, and Alberta.

Four white toothbrush-like tufts stand out from the back, and a gray-brown hair pencil is at the hind end.

[citation needed] The four white tufts on the larva's back may mimic the cocoons of parasitic wasps.

The males are gray with wavy black lines and a white spot on the forewings (the vapourer, Orgyia antiqua, is similar but is a rusty color.)

The caterpillars may be found feeding on an extremely wide variety of trees, both deciduous and coniferous, including apple, birch, black locust, cherry, elm, fir, hackberry, hemlock, hickory, larch, oak, rose, spruce, chestnut, and willow.

The fungus Entomophaga maimaiga was introduced to North America to control the spongy moth (Lymantria dispar).