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'm unsure which species this is: it lacks the usual features of B. laurentina, but it's small, so maybe it's just an underdeveloped early instar. Otherwise, it looks like it might be B. obesa.
This mayfly was collected from unknown in Wisconsin on January 14th, 2004 and added to Troutnut.com by Troutnut on January 25th, 2006.