Northern Prairie Wildlife Research Center
This brownish black caterpillar has whorls of orange hairs on dorsal and subdorsal black spines. Black spines also occur laterally and sublaterally with off-white hairs; white spiracular band. Gregarious early instars are solid black. The hairy spines of this caterpillar are urticating. This species is common on bitterbrush and serviceberry during May and June.