University of Alberta Museums Search

A large geometrid, the thin wings and proportionately small body gives it a "flimsy" demeanor. Ground colour light grey with black speckling, often with shades of brown along the forewing costa and apex. The jagged AM and PM lines resemble a dog's head in profile, with the white discal spot forming the eye. The extent of the forewing dark markings, including the transverse lines, can be extremely variable, resulting in well-marked, contrasting individuals to almost unmarked grey ones.

McGuffin (1981) details the early stages. The mature larva (illustrated in Wagner et al. 2001) shows an intricate pattern of black and brown, resembling tree bark or a twig. As a defensive mechanism, larvae are able to "snap" their bodies, jumping off their resting perch. The pupa overwinters in a thin cocoon in leaf litter (Hardy 1957).

Larvae have variously been reported as feeding on willows (Salix, trembling aspen (Populus tremuloides), lodgepole pine (Pinus contorta) and Douglas-fir (Pseudotsuga) (McGuffin 1981). In Alberta, this species has been found only in association with conifers, and is apparently absent from the aspen parkland and prairie regions.