Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
This specimen keys to Isoperla fusca using the key in Szczytko & Stewart 1979, but some species of Isoperla weren't represented there. It's probably the same species as this one collected a year later. Despite taking many good pictures of both, I'm not sure of the species ID.
This stonefly was collected from the Yakima River in Washington on April 9th, 2021 and added to Troutnut.com by Troutnut on April 12th, 2021.