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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.

Artistic view of a Perlodidae (Springflies and Yellow Stones) Stonefly Nymph from the Yakima River in Washington
This one seems to lead to Couplet 35 of the Key to Genera of Perlodidae Nymphs and the genus Isoperla, but I'm skeptical that's correct based on the general look. I need to get it under the microscope to review several choices in the key, and it'll probably end up a different Perlodidae.
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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Female Rhithrogena Mayfly Spinner Pictures

I'm very tentatively (see the connected forum thread) sticking this mayfly in Rhithrogena for now.

Female Rhithrogena (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Female Rhithrogena (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Female Rhithrogena (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Ventral view of a Female Rhithrogena (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Lateral view of a Female Rhithrogena (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Female Rhithrogena (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
This image is overly enhanced to better show the structure of the veins.

Female Rhithrogena (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Dorsal view of a Female Rhithrogena (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York
Ruler view of a Female Rhithrogena (Heptageniidae) Mayfly Spinner from the West Branch of the Delaware River in New York The smallest ruler marks are 1 mm.

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.

Discussions of this Spinner

What genus is this Heptageniid?
4 replies
Posted by Troutnut on Jun 8, 2007
Last reply on Feb 1, 2009 by Taxon
I didn't even recognize it as a member of that family at first, but it seems to be the only option. The hind tarsus is distinctly 5-segmented, which I verified under the microscope because you can't see it very well on my photos. However, I because it's a female spinner I can't key it to genus using the Merrit & Cummins keys. Does anyone just recognize it?

I found it drifting, nearly dead on the surface at about 5pm on a hot afternoon.

Start a Discussion of Spinner

Female Rhithrogena 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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