The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
This species is very abundant in Flathead and Whitefish Lakes with a smaller population in lakes of the Swan River Drainage, and a few in Lake McDonald in Glacier Park. This species usually emerges along with Ephemera simulans.
This mayfly was collected from Flathead Lake in Montana on July 31st, 2010 and added to Troutnut.com by Bnewell on June 29th, 2011.