Moved from Rhithrogena hageni.

Hi Laurent,

This is not Rhithrogena. All species in that genus have a transverse mesonotal suture, which is a little groove in the shape of an arc that crosses the forward slope of the mesonotum. The heptageniid genera that lack a transverse mesonotal suture are Epeorus and Ironodes. Both are found in the West.

Your female subimago is Epeorus albertae, known as the (Western) "pink lady" to flyfishers. Its counterpart in the East is Epeorus vitreus, also known as a "pink lady." Both are named for a famous fly pattern created by George LaBranche, and for the color of the egg-laden female imagos (and to a lesser extent, the subimagos).

Both the Western and the Eastern species also share these identifying traits: a darkened humeral vein at the base of the forewings, femora that are marked by a dark spot near the middle and a band at the apex, and a dark line across the rear of terga.

Best,
Lloyd

Moved from Mayflies.

Hi Laurent-

Yes, I believe this female subimago to be Rhithrogena hageni.

Moved from ID Request.

Roger will take the ID further.

Is it a Rhithrogena if so which species should I go for?