The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
This one was collected in in association with this male. It looks quite different, but that's often the case between spinner genders.
This mayfly was collected from unknown in Wisconsin on August 5th, 2004 and added to Troutnut.com by Troutnut on January 19th, 2006.