Northern Prairie Wildlife Research Center
Brown, black, and white with raised warts on dorsum of first, fourth, and eighth abdominal segments. Top of head red; triangle with broad black band to either side; sides of head mottled. Warts arranged as transverse line over dorsum of first and second abdominal segments, but form square on eighth segment. White hairs on dorsum short and bladelike; those on side long and downy. Food: especially elms, but also apples, basswoods, and others. Caterpillar: May to October; 2 or more generations.