This specimen resembled several others of around the same size and perhaps the same species, which were pretty common in my February sample from the upper Yakima. Unfortunately, I misplaced the specimen before I could get it under a microscope for a definitive ID.
This is one of the most common Rhyacophila species in the East and Midwest, and it was reported by the Leonards as the most common in the Lower Peninsula of Michigan.
In 14 records from GBIF, adults of this species have been collected during May (57%) and June (43%).