The head is cherry red. On the second segment behind the head are two long, slender, slightly curved black horns. Short black spines occur along the sides of the body. On the lower side of the body near the rear is a rose colored area. Large colonies of caterpillars sometimes strip host trees in the mid-west.
Winter is spent in the soil as a dark brown, hard-shelled pupa slightly less than one inch long.
The moths emerge in May and begin laying eggs on the underside of leaves. Each female lays about 150 eggs. Egg hatch in about eight to ten days, and the young caterpillars begin to feed. A second brood of moths appear later in the season. In the moth stage this resembles the orange-striped oakworm, but is more densely flecked with dark spots.