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 the Neoleptophlebia memorialis group, which means it could be Neoleptophlebia memorialis or Neoleptophlebia temporalis. In the absence of a clear species key, I'm just guessing memorialis for now.
This mayfly was collected from the Dosewallips River in Washington on July 6th, 2020 and added to Troutnut.com by Troutnut on July 12th, 2020.