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Lateral view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Dun from the Namekagon River in Wisconsin
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.

Dorsal view of a Holocentropus (Polycentropodidae) Caddisfly Larva from the Yakima River in Washington
This one seems to tentatively key to Holocentropus, although I can't make out the anal spines in Couplet 7 of the Key to Genera of Polycentropodidae Larvae nor the dark bands in Couplet 4 of the Key to Genera of Polycentropodidae Larvae, making me wonder if I went wrong somewhere in keying it out. I don't see where that could have happened, though. It might also be that it's a very immature larva and doesn't possess all the identifying characteristics in the key yet. If Holocentropus is correct, then Holocentropus flavus and Holocentropus interruptus are the two likely possibilities based on range, but I was not able to find a description of their larvae.
27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.
Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Updates from July 12, 2005

Updates from July 12, 2005

Photos by Troutnut from the East Branch of the Delaware River in New York

My girlfriend casts amidst a mix of bugs hatching in mid-July from a Catskill stream.

From the East Branch of the Delaware River in New York
A large, slow Catskill trout river meanders in the shadow of a mountain.

From the East Branch of the Delaware River in New York
The East Branch of the Delaware River in New York

Closeup insects by Troutnut from the East Branch of the Delaware River and Miscellaneous New York in New York

Lateral view of a Male Afghanurus inconspicua (Heptageniidae) Mayfly Dun from the East Branch of the Delaware River in New York
This pretty little dun was part of a sparse midsummer evening hatch on a large Catskill river.

I could not identify it by following a species key step by step, but I tentatively keyed it to the genus Nixe, and based on distribution maps and physical descriptions the most likely species is Nixe inconspicua. (Edit in 2023: this species was recently moved from Nixe into Afghanurus.)
Ruler view of a Female Hexagenia limbata (Ephemeridae) (Hex) Mayfly Spinner from Gas station in Whitney Point, NY in New York The smallest ruler marks are 1 mm.
I found this Hexagenia limbata spinner on a gas station in upstate New York, not a region known for heavy hatches of this species.

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