Like most species in this family, it has chemical defenses it acquires from its host plants, in this case, cardiac glycosides. These are retained in adults and deter bats, and presumably other predators, from feeding on them.
Early instars appear slightly hairy and gray. Later instars sport tufts of black, white and orange (sometimes yellow) setae. The head capsule is black. Larvae grow as long as 35 mm. In moth form, wings are grayish. Abdomens are hairy and yellow, each with a row of black dots on its dorsum.
It is a common mid- through late-summer feeder on milkweeds and dogbane. Mature caterpillars occur from June onwards.