The saltmarsh caterpillar is in the family Arctiidae. The larvae are very hairy and the early instars may be yellowish-white. In the early instars the caterpillars feed gregariously on the foliage of soybeans, cotton, and many greenhouse crops. Older larvae are reddish brown and over 5 cm in length. They overwinter in the pupal state as brown hairy cocoons in the debris in the ground.
Adults appear in the spring.
The female adults are white on the top of the wings and yellow on the underside. The males are similar, except the hind wings are yellow both on the top and underside. Both sexes have numerous black spots on the wigs. The spherical eggs are laid in masses on plant foliage. The pale green or cream eggs are laid singly on leaves and stems of host plants.