This massive moth can be found from British Columbia east to western Montana, south through Washington, western Oregon, and California to Baja California Sur. There is only one brood a year with adults generally emerging from mid May to mid June in western Montana. Adults do not feed, focused solely on passing their genes onto the next generation. Larvae feed on a large number of trees and shrubs, including its namesake Ceanothus. It strongly resembles the Glover’s Silkmoth (also found in Montana), which has a grayish border to the wings as opposed to the Ceanothus Silkmoth’s reddish / pink border.
Photo by: Kristi DuBois on 6/4/21 in Missoula, MT