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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.
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Male Stenonema terminatum Mayfly Spinner Pictures

I positively identified this specimen under a microscope with a good key. It was one of the more common species in a generally light mixed bag of mayflies over a big Catskill tailwater last night.

I swooped this one out of the air while it was mating with a female, so I can be certain about her ID as well.

Ruler view of a Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York The smallest ruler marks are 1 mm.
Lateral view of a Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Artistic view of a Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Dorsal view of a Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Male Stenonema terminatum (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York

This mayfly was collected from the West Branch of the Delaware River in New York on June 7th, 2007 and added to Troutnut.com by Troutnut on June 8th, 2007.


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Male Stenonema terminatum Mayfly Spinner Pictures

Collection details
Location: West Branch of the Delaware River, New York
Date: June 7th, 2007
Added to site: June 8th, 2007
Author: Troutnut
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