: As "inchworms," the larvae lack several pairs of central prolegs. They move by drawing their hind end up to their front legs, forming a high arch (or "loop") before reaching forward again.
: Larvae are about 25 mm long and vary in color from light green to dark brownish-green. A distinguishing feature is that fall cankerworms have three pairs of prolegs on the rear half of their abdomen, whereas the similar spring cankerworm has only two. alsophila pometaria
: This species exhibits extreme physical differences between sexes. Adult males have a 25–35 mm wingspan with glossy brown or gray wings. Females are entirely wingless , grayish-brown, and approximately 10–12 mm long. : As "inchworms," the larvae lack several pairs
The ( Alsophila pometaria ) is a native North American moth best known for its "inchworm" larvae that can cause significant defoliation of broadleaf trees. Despite their name, they are primarily a spring-feeding pest, though adults emerge in the late autumn to breed. Key Biological Features A distinguishing feature is that fall cankerworms have