The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
I've seen Ephemerella invaria with green egg sacs and Ephemerella subvaria with yellow one. This one seems too large for dorothea. So what is it? I'm not sure.
Many females of this species were gathered in tight clouds to lay their eggs over the riffles in a mid-sized Pocono stream right at dusk. It would have been a fishable spinner fall if I'd stuck around to wait for them.
This mayfly was collected from Mystery Creek #42 in Pennsylvania on May 28th, 2007 and added to Troutnut.com by Troutnut on June 4th, 2007.