Northern Prairie Wildlife Research Center
Stocky, gray to brown, with subtle pinstriping and uniquely thickened third thoracic segment. Head with reticulate pattern of dark mottling, which carries onto body. Rusty orange spiracles often embedded in dark lateral patch. Third thoracic segment considerably swollen at leg base. Abdomen often looped upward immediately behind thorax. Anal proleg stout with vertical crease or line. Food: many forest hardwoods. Caterpillar: May to November; 1 or 2 generations.