Northern Prairie Wildlife Research Center
Wingspan 9.1 cm. Forewing is dark black-gray with a pale gray discal area, narrow black streaks, and a pale gray submarginal line; hindwing is pale gray with black median and submarginal bands; thorax mostly black; abdomen with black and white lateral spots. This sphingid is abundant in dry forests in the Pacific West. Moths fly in spring and early summer. Caterpillars feed on the foliage of species of Ceanothus.
Similar species: Sphinx drupiferarum forewing is black with a contrasting white discal area, widely distributed in western North America, caterpillars feed on the foliage of cherry (Prunus) and apple (Malus); Sphinx vashti is smaller, forewing with a black postmedian line, caterpillars feed on the foliage of snowberry (Symphoricarpos albus).