Northern Prairie Wildlife Research Center
Blackish, dappled with few to many yellowish flecks, often with diffuse spiracular stripe. Body densely covered by prominent tufts of branched spines, which tend to be shorter than those of buck moth. Gregarious in early instars then becoming solitary. Spines inflict painful sting followed by swelling. Food: early instars on meadowsweet, but by fourth instar wanders onto oaks, willows, and many other shrubs and trees. Caterpillar: May to July; 1 generation.