This may look like a fly (and have “fly” in its name), but it is actually in the order Hymenoptera (wasps, bees, and ants). Abia Americana is in the genus Cimbicidae and is the only member of this genus in western North America.Their larvae are caterpillar-like in appearance and seem to be fond of snowberry.
Photo by Glenn Marangelo on 4/21/20 in Missoula, MT