Northern Prairie Wildlife Research Center
Green with dorsal brown markings over thoracic and second to fifth and eighth abdominal segments. Spiracles small, whitish, rimmed with pale orange. Venter of second abdominal segment with brown patch that may join dorsal patch; spiracular area of second segment swollen. Thoracic and midabdominal prolegs darkened. Dorsum of eighth abdominal segment with low, black warts. Head flat-faced, mottled orange brown, lobed above, with broad darkened band that meets over head and may continue onto thorax; this band narrowing to eyes, leaving pale "cheek" patch. Food: many deciduous trees. Caterpillar: May to October; 2 generations in North.