Montana Field Guide

The forewing of Xestia mustelina is pink-gray with very large gray discal spots outlined in black. The wingspan is about 36 mm (USGS 2006). The hindwings are pale smoky brown (Davis 2007).

Shropshire and Tallamy (2025) provide a list, with synonymies, of 13,055 described native, exotic, and occasional straying Lepidoptera species of North America, north of Mexico; known but undescribed taxa, taxa with unresolved taxonomy, and excluded species are also included. The main manuscript includes links to supplementary materials, including a reference list for Lepidoptera of North America north of Mexico, and a filterable spreadsheet with information on taxonomy, synonymy, size ranges of species, distribution by state, province, and country with references, and host-plant Family and Genus associations with references.

Adults fly mainly from mid-July to September (Davis 2007).

X. mustelina is common and widely distributed in wet conifer forests in the Pacific West and in the northern Rocky Mountains (USGS 2006).

Shropshire and Tallamy (2025) provide a link to a supplemental filterable spreadsheet with information on host-plant Family and Genus associations with references for all Lepidoptera species of North America, north of Mexico.

The larvae feed on the foliage of species of Pinaceae, in particular Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla) and flowering trees and shrubs such as madrone (Arbutus menziesii), myrica (Myrica), and huckleberry (Vaccinium) (USGS 2006).