We initially thought this was a type of tussock moth caterpillar, with all of the tufts of hair, but arrived at a species whose larvae are thought to mimic them. The Yellow-haired Dagger is common and widely distributed in hardwood forests throughout much of North America. Larvae are generalist feeders of many hardwood trees and shrubs, but prefer cottonwoods, willows, birches, and alders. Adults are muted in color, nocturnal, and will come to lights. 

Size: Forewing length 20 – 22 mm

Photo by: Ellen Knight on 8/22/21 in Missoula, MT