Females are darker and much larger than males. Forewing has a light brown costa and a faint median band.
Females lay rings of eggs around the stems of both host and nonhost plants.
Eggs overwinter and hatch the following May or June. Young caterpillars feed in groups while older caterpillars are solitary feeders. One brood from September-December. G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery. The stinging hairs of the caterpillars can irritate livestock.