We have a bit of a mystery here, but that’s okay! All three of these species can be found in Montana …and the chokecherry it is munching on is among several hosts for all three. This particular caterpillar is in its third instar (developmental stage between molts), and from a trusted source, the 4th to 5th can more easily be determined. We do know that this beautiful caterpillar (if all goes well) will spend some more time feeding and growing, then weave a thick, silken cocoon for its winter “nap” and emerge in the spring to find a mate.
Photo by Melissa Mathis on 8/5/20 in Greenough, MT.