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.
A large number of photos from the microscope allowed a fairly confident ID on this one, which not coincidentally matches very well a previous specimen of Suwallia pallidula that I collected in Washington.
This stonefly was collected from Mystery Creek #237 in Montana on August 1st, 2020 and added to Troutnut.com by Troutnut on August 18th, 2020.