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 one doesn't have the protruding mouthparts typical of Cinygmula, but I think it's just an oddball individual.
This mayfly was collected from Swauk Creek in Washington on June 13th, 2022 and added to Troutnut.com by Troutnut on June 14th, 2022.