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.
Here's the first sulphur dun I found in the 2004 season.
This mayfly was collected from the Namekagon River in Wisconsin on May 18th, 2004 and added to Troutnut.com by Troutnut on January 25th, 2006.