Northern Prairie Wildlife Research Center
Wingspan 6.4 cm. Forewing is rose-pink and orange with black basal and postmedian bands, a round reniform spot and submarginal dashes; hindwing is orange with a similar pattern of black as on the forewing; abdomen orange with black bands. Color variants may lack all black markings, with pure unmarked rose and orange wings (left photo), or the black markings may be distinct (right photo) or greatly enlarged over most of the wing. This saturniid is common and widely distributed in western North America. Moths fly during the day in midsummer. Caterpillars are generalist feeders on the foliage of flowering trees and shrubs, particularly Rosaceae such as rose (Rosa), hawthorn (Crataegus), cherry (Prunus), serviceberry (Amelanchier alnifolia), and bitterbrush (Purshia tridentata).
Similar species: Hemileuca nuttalli forewing is yellow, hindwing with a v-shaped black postmedian band, widely distributed in dry forests east of the Cascade Mountains, caterpillars feed on bitterbrush; Hemileuca hera wings are white with comma-shaped black reniform spots, widely distributed in juniper woodlands and sagebrush steppes, caterpillars feed on sagebrush (Artemisia tridentata); Hemileuca nevadensis wings are black with a broad white median band, occurs in wet forests and riparian habitats east of the Cascade Mountains, moths fly in fall and caterpillars feed on foliage of willow (Salix) and poplar (Populus).