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 keyed easily to Leptoceridae, but I hit a bit of a dead end in the genus key, because I can't seem to find the cross-veins in the wings that are supposed to help narrow it down. I took pictures of all the relevant features under the microscope; maybe somebody with more experience with the family can help.
This caddisfly was collected from the Henry's Fork of the Snake River in Idaho on July 31st, 2020 and added to Troutnut.com by Troutnut on August 17th, 2020.