The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
Unfortunately there's no good key to species of Cinygmula nymphs and I didn't find an adult, so this one will have to stay at genus level.
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.