Northern Prairie Wildlife Research Center
Highly variable, most individuals bicolored, marked with browns and blacks dorsally, paler, often yellowish green laterally and ventrally; other individuals very dark, usually with some light areas below abdominal spiracles of at least first 3 abdominal segments and above midabdominal proleg. Head pale brown or orangish, usually mottled. Legs pale with darkened claws. Dorsum of second, third, and eighth abdominal segments with slightly raised darkened warts; often subtly striped down to black or white supraspiracular area. Food: oaks, elms, and other trees. Caterpillar: May to July; 1 generation.