Northern Prairie Wildlife Research Center
Similar to sigmoid prominent, dark ground color with conspicuous yellow to orange stripes. Head uniformly black. Hairs sparser than in sigmoid prominent. First and eighth abdominal segments with medial black warts of roughly equivalent size. Gregarious in nests of folded leaves by day, through last instar. Food: willows and poplars. Caterpillar: May to September; 2 generations.