Males and females differ.
Male abdomen is black with a red tip, female abdomen is all black.
On the forewing the median band is indented by a tan cell spot. Females lay rings of eggs around twigs of the host. Eggs overwinter and usually hatch in April. Young caterpillars feed together on oak flowers and older caterpillars feed mostly on leaves. Fully-grown caterpillars spin loose cocoons in leaf litter.