Hex Mayflies
Hexagenia limbata

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.

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Re: UV spectrum and trout
In General Discussion by Martinlf

Re: closing the gender gap in flyfishing
In General Discussion by Konchu (Smallflyguy replied)

Re: Fishing Kupa River, Slovenia
In Fishing Reports by Slocum (Fish1 replied)

Re: Clinger nymphs are shaped that way to hang in really fast currents. Really?
In the Mayfly Genus Rhithrogena by Entoman (Steamntrout replied)

Male Glossosoma (Little Brown Short-horned Sedges) Saddle-case Maker Adult Pictures

Key characteristics verified under the microscope:
-The head has 3 ocelli.
-Maxillary palp has 5 segments, with the second segment rounded. In some of the pictures it looks like 6 with the 3rd segment rounded, but the basal "segment" in that case isn't part of the palp.
-Foretibiae lack preapical spurs.
-Pronotum with mesal setose warts widely spaced.

All of this very clearly indicates Glossosomatidae. Beyond there:

-The tibial spur counts (fore / middle / hind tibiae) are 2, 4, and 4.
-From the pictures, the hind wing discoidal cell is closed, not open. Subfamily Glossosomatinae.
-The upper and lower parts of the mesepisternum are separated by a constriction, not a transverse suture. Microscope picture included.

This leads to a very confident genus ID of Glossosoma. I don't have the information to take it to species.