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Large Mahogany Duns

Scientific Name
MatchScientific Name
**Isonychia bicolor


This common name refers to only one species.

Mayfly Species Isonychia bicolor

These are sometimes called Large Mahogany Duns.
This is by far the most important species of Isonychia. Many angling books once split its credit with the species Isonychia sadleri and Isonychia harperi, but entomologists have since discovered that those are just variations of this abundant species.

See the main Isonychia page for more about these intriguing mayflies.
Isonychia bicolor (Mahogany Dun) Mayfly NymphIsonychia bicolor (Mahogany Dun) Mayfly Nymph View 7 PicturesThis Isonychia bicolor nymph from the Catskills displays the prominent white stripe sometimes characteristic of its species. This is the first such specimen I've photographed, because members of the same species in the Upper Midwest have a more subdued stripe (and were once thought to be a different species, Isonychia sadleri). The striking coloration on this eastern nymph is more appealing.
Collected April 19, 2006 from in
Added to Troutnut.com by on April 21, 2006
Female Isonychia bicolor (Mahogany Dun) Mayfly DunFemale Isonychia bicolor (Mahogany Dun) Mayfly Dun View 13 Pictures
Collected June 14, 2005 from in
Added to Troutnut.com by on May 26, 2006
Male Isonychia bicolor (Mahogany Dun) Mayfly SpinnerMale Isonychia bicolor (Mahogany Dun) Mayfly Spinner View 15 PicturesI got several really nice pictures of this spinner. I also collected a female on the same trip.
Collected August 9, 2006 from in
Added to Troutnut.com by on August 11, 2006
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