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.
Looking at this specimen under a microscope revealed prominent sharp abdominal tubercles. Also, abdominal segment 9 is distinctly longer than abdominal segment 8, meaning this is definitely a Eurylophella nymph.
This mayfly was collected from unknown in Wisconsin on February 7th, 2004 and added to Troutnut.com by Troutnut on January 25th, 2006.