Northern Prairie Wildlife Research Center
The presence of two pairs of midabdominal prolegs is an unusual feature for inchworms. In this species the prolegs on A5 are slightly reduced. In contrast the middabdominal prolegs on A5 and A6 in plusiines (Noctuidae) are nearly equal in size (see Autographa californica). The body color is variable in this species but is generally drab, such as the rosy green depicted here. The ventral fringe of knobby hairs is unique among inchworms in the Pacific Northwest. This species is common on many broadleaf trees such as serviceberry, red and mountain alder, and hazel, during April and May.