University of Alberta Museums Search

A medium-size moth (3.5-3.8 cm wingspan) with dark chestnut brown forewings dusted with black scales. The subterminal area is usually lighter in color than the median area, and the terminal area is dark grey brown. The costa and cubital vein are much lighter and contrasting buff or silvery white. The reniform spot and oval orbicular spot are also buff or silver white, with pale grey centers. The basal dash and claviform spots are black, as is the area between the reniform and orbicular spot in most specimens. The hindwings are grey-brown, with a dark discal mark. The antennae of males are biserrate and bifasciculate, and females are simple (filiform). The chestnut color of the forewings and the pale cubital vein will separate castanea from the similar but dark grey or brown E. idahoensis. It belongs to the E. detersa group of the genus Euxoa.

From the Dakotas and southwestern Manitoba west to central western BC, north to the Northwest Territories and south in the mountains to Arizona and New Mexico. Euxoa castanea occurs throughout much of Alberta, but is most commonly collected in wooded areas across the southern half of the province, and in particular in the foothills and mountains.