Utah State University Extension
Cankerworms, also known as inchworms, are in the order Lepidoptera and family Geometridae. Geometrid moth adults have slender bodies and relatively large, broad forewings (Figs. 1, 3). Both fall, Alsophila pometaria, and spring, Paleacrita vernata, cankerworms occur in Utah, with the fall cankerworm being most common.
Murray, Marrion S. and Hodgson, Erin W., "Cankerworms" (2008). All Current Publications. Paper 868.