Header image
Enter a name
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.

Lateral view of a Male Baetidae (Blue-Winged Olive) Mayfly Dun from Mystery Creek #308 in Washington
This dun emerged from a mature nymph on my desk. Unfortunately its wings didn't perfectly dry out.
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.

Female Ephemerella excrucians (Pale Morning Dun) Mayfly Spinner Pictures

Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Spinner from the Bois Brule River in Wisconsin
Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Spinner from the Bois Brule River in Wisconsin
Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Spinner from the Bois Brule River in Wisconsin
Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Spinner from the Bois Brule River in Wisconsin
Lateral view of a Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Spinner from the Bois Brule River in Wisconsin
Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Spinner from the Bois Brule River in Wisconsin
Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Spinner from the Bois Brule River in Wisconsin
Dorsal view of a Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Spinner from the Bois Brule River in Wisconsin
Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Spinner from the Bois Brule River in Wisconsin
Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Spinner from the Bois Brule River in Wisconsin
Ventral view of a Female Ephemerella excrucians (Ephemerellidae) (Pale Morning Dun) Mayfly Spinner from the Bois Brule River in Wisconsin

This mayfly was collected from the Bois Brule River in Wisconsin on July 1st, 2005 and added to Troutnut.com by Troutnut on April 22nd, 2006.

Discussions of this Spinner

I'm pretty unsure about these IDs
5 replies
Posted by Troutnut on Jul 4, 2006
Last reply on Dec 18, 2013 by Brookyman
I wish I had been able to get a male spinner for a positive ID. I wasn't able to collect any, unfortunately. The keys I have to the adult genera of the Ephemerellidae require one.

I've placed several specimens collected from a similar emergence on nearby rivers into the species Attenella attenuata, because they look exactly like the picture of that species in some books, most recently Ted Fauceglia's Mayflies. They are handy midday and early evening emergers in northwest Wisconsin at a time when not much else is on the water. But I'm not convinced that the identification is correct.

For one thing, although I tried sampling several times in stretches where the duns were emerging, the only mature Ephemerellid nymphs I found keyed out to Ephemerella inermis, which is now Ephemerella excrucians. These adults fit the general description for that widely variable species. I never found any Attenella nymphs.

I suspect they are the same species referred to in nearby parts of Wisconsin as "Kinni Sulphurs" and "Booger Sulphurs." As best I can tell from looking up those names, they seem to have been identified as Ephemerella inermis but there is a local belief that they are Ephemerella needhami, even though their color does not at all fit the description for that species.

Ah, to have a male spinner under the microscope...
Now that's aBWO!!
2 replies
Posted by Adirman on Sep 10, 2010
Last reply on Sep 10, 2010 by Taxon
That Attenuata looks like it truly has the olive body, more so than any BWO pic i've seen yet! Wah tsize would that be tied in to imitate?

Thanks,

Adirman

Start a Discussion of Spinner

Female Ephemerella excrucians (Pale Morning Dun) Mayfly Spinner Pictures

Collection details
Location: Bois Brule River, Wisconsin
Date: July 1st, 2005
Added to site: April 22nd, 2006
Author: Troutnut
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy