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Pteronarcys californica

The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.

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Male Epeorus frisoni Mayfly Dun Pictures

I collected this male dun together with a female spinner, a female dun, and another male dun.

This mayfly was collected from Mystery Creek #23 in New York on September 6th, 2006 and added to Troutnut.com by Troutnut on October 3rd, 2006.

Discussions of this Dun

A mystery late-season Epeorus
7 replies
Posted by Troutnut on Oct 3, 2006
Last reply on May 9, 2012 by Entoman
This Epeorus species was the only significant hatch I encountered in the remote headwaters of a Catskill stream one afternoon (September 6th, 2006). The small stream is incredibly clear and reportedly very acidic. The duns were coming off sporadically all afternoon and evening on this pleasantly warm, mostly cloudy day with a fleeting dash of rain at one point and sunshine at another. The female spinners were around the whole time but were much more common over the riffles toward evening in groups of 2-10. They were diving to the surface to lay eggs by quickly dipping their abdomens into the water and rising up again for a repeated run.

I couldn't find any male spinners, which might make identification impossible, but I did photograph the following:

Hopefully this will be enough to eventually puzzle out the ID of this pretty little species.
Epeorus May Fly
1 replies
Posted by Goose on Oct 4, 2006
Last reply on Oct 4, 2006 by Troutnut
Nice photos, Jason. Are these the fall Sulphur Mayflies that have been discussed here and on a Pennsylvania web site?

Start a Discussion of Dun

Male Epeorus frisoni Mayfly Dun Pictures

Collection details
Location: Mystery Creek #23, New York
Date: September 6th, 2006
Added to site: October 3rd, 2006
Author: Troutnut
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