Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York

Blue-winged Olives
Baetis

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

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Sweltsa (Sallfly) Stonefly Nymph Sweltsa (Sallfly) Stonefly Nymph

Dorsal view of a Sweltsa (Chloroperlidae) (Sallfly) Stonefly Nymph from the Yakima River in Washington

This species was fairly abundant in a February sample of the upper Yakima.

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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

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

Artistic view of a 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?

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