American Dagger Moth Caterpillar (Acronicta americana):  These colorful caterpillars are primarily found in the central and eastern states, but can be found in areas east of the continental divide. They can reach up to 2 inches in length, feeding on alders, ashes, birches, elms, hickories, maples, oaks, poplars, walnuts, and willows. Five bunches of black bristles / hairs extend from the body and contain toxins that cause a stinging sensation …so better to observe and not touch. Photo by Sarah Wood Chatwood on 9/25/18 at the Montana Audubon Center in Billings, MT.