The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
This dun is almost certainly of the same species as this nymph, as it hatched in my cooler from a nearly identical nymph.
This mayfly was collected from Nome Creek in Alaska on July 10th, 2011 and added to Troutnut.com by Troutnut on July 13th, 2011.