Northern Prairie Wildlife Research Center
Wingspan 8.2 cm. Forewing is dark gray with a black basal area, a pale gray discal area and a black postmedian line; hindwing is white with black median and submarginal bands; thorax is black to gray; abdomen with black and white lateral spots. This sphingid is abundant in wet forests in much of western North America. Moths fly in spring and early summer. Caterpillars feed on the foliage of snowberry (Symphoricarpos albus).
Similar species: Sphinx perelegans is larger, forewing without a black postmedian line, caterpillars feed on the foliage of species of Ceanothus; Sphinx sequoiae is smaller, hindwing is gray, caterpillars feed on the foliage of juniper (Juniperus).