The Unicorn Caterpillar Moth is aptly named …and that hump / horn is not for show. According to the University of Alberta Museums, “Caterpillars in this genus are unusual in that they can eject a stream of formic acid for up to several inches from a gland in the hump.” Don’t worry, Taylor didn’t get sprayed. Caterpillars munch on a variety of broad-leaved trees and shrubs, with this particular one found on Taylor’s roses. Adults fly from May to mid September in the Pacific Northwest. They are found in all of North America except for the arctic (absent only from Nunavut, Northwest Territories, Yukon, and Alaska) in deciduous woodlands and shrubby areas.
Photo by: Taylor Marston on 8/6/21 in Missoula, MT