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.
I found this female in the same area as a male with similar markings, probably of the same species.
This mayfly was collected from Mystery Creek #43 in New York on September 19th, 2006 and added to Troutnut.com by Troutnut on October 4th, 2006.