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 took quite a few notes at the microscope when I collected this specimen. They're attached to the appropriate pictures.
I found this specimen in the same collection as a similar one. Since I only have strange views of this one, it's possible that they're actually the same specimen and I somehow confused my picture-ordering and got the impression that they're different nymphs.