The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
This specimen seems to be morphologically identical to the darker specimens of its species, but it's a very distinctly different color. I'm guessing this is a gender difference, just as I've guessed for the similar E. subvaria nymphs.
This mayfly was collected from unknown in Wisconsin on February 5th, 2004 and added to Troutnut.com by Troutnut on January 25th, 2006.