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 Isonychia bicolor (Mahogany Dun) Mayfly Dun Pictures

Lateral view of a Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Dorsal view of a Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Ventral view of a Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Ruler view of a Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Artistic view of a Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin
Female Isonychia bicolor (Isonychiidae) (Mahogany Dun) Mayfly Dun from the Namekagon River in Wisconsin

This mayfly was collected from the Namekagon River in Wisconsin on June 14th, 2005 and added to Troutnut.com by Troutnut on May 26th, 2006.

Discussions of this Dun

Isos with green edged wings
3 replies
Posted by Kenlindblom on Jul 26, 2013
Last reply on Jul 28, 2013 by Martinlf
I have seen Isos with the forward edge of their wings an olive color. These were also on the upper East Branch. I tied some using a permanent marker to tint the leading edges olive. But, it seems that the standard pattern works as well.
Iso dun
16 replies
Posted by Wbranch on Feb 12, 2010
Last reply on Jun 5, 2010 by Vinlflyfish
In Paul Weamer's book (page 190) "Fly Fishing Guide to the Upper Delaware River" he writes "Some Upper Delaware Isonychias are bright green when they first emerge. They eventually change into their reddish purple to grayish pink color as they are exposed to the air". I'd like to tie some of these but would like to see a decent picture of the adult insect as it first emerges. Anyone have any pictures with the bright green abdomen?

Start a Discussion of Dun

Female Isonychia bicolor (Mahogany Dun) Mayfly Dun Pictures

Collection details
Location: Namekagon River, Wisconsin
Date: June 14th, 2005
Added to site: May 26th, 2006
Author: Troutnut
Troutnut.com is copyright © 2004-2024 (email Jason). privacy policy