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Mayfly Genus Isonychia (Slate Drakes)

Taxonomic Navigation -?-
Species in IsonychiaNumber of SpecimensNumber of Pictures
Isonychia bicolorMahogany Dun1997
Isonychia campestrisSlate Drake00
Isonychia siccaSlate Drake00
Isonychia velmaSlate Drake00

12 species aren't included.
Common Names
Pictures Below

This is page 2 of specimens of Isonychia. Visit the main Isonychia page for:

  • The behavior and habitat of Isonychia.

Pictures of 20 Mayfly Specimens in the Genus Isonychia:

Specimen Page:123
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 the Beaverkill River in New York
Added to by Troutnut on April 21, 2006
Female Isonychia bicolor (Mahogany Dun) Mayfly DunFemale Isonychia bicolor (Mahogany Dun) Mayfly Dun View 6 PicturesI thought this dun was worth photographing, even though she's in pretty bad shape, because she shows something I haven't seen in Isonychia elsewhere. The bright stripe down the back which is normally present only in the nymph carried over to the dun in this one.
Collected May 26, 2007 from Penn's Creek in Pennsylvania
Added to by Troutnut on June 4, 2007
Isonychia (Slate Drakes) Mayfly NymphIsonychia (Slate Drakes) Mayfly Nymph View 3 PicturesThis smaller Isonychia nymph was caught with a bunch of bicolor specimens, but it does not have the fluffy spine structure at the base of its gills. This might mean it's Isonychia sayi, or it might just be a bicolor nymph too young to have developed those structures.
Collected January 13, 2004 from the Namekagon River in Wisconsin
Added to by Troutnut on January 25, 2006
Specimen Page:123
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