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Mayfly Genus Rhithrogena

Mayflies

Caddisflies

Stoneflies

Taxonomic Navigation -?-

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Heptageniidae (March Browns, Cahills, Quill Gordons)

» Genus Rhithrogena

Species in Rhithrogena
Rhithrogena futilisWestern Gordon Quill	0	0
Rhithrogena hageniWestern Black Quill	0	0
Rhithrogena impersonataDark Red Quill	0	0
Rhithrogena jejunaDark Red Quill	0	0
Rhithrogena manifesta	0	0
Rhithrogena morrisoniWestern March Brown	0	0
Rhithrogena robusta	0	0
Rhithrogena undulataSmall Western Red Quill	0	0
Rhithrogena virilis	0	0

14 species aren't included.

Pictures Below ↓

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

The behavior and habitat of Rhithrogena.

Pictures of 28 Mayfly Specimens in the Genus Rhithrogena:

Specimen Page:123 4

Rhithrogena impersonata (Dark Red Quill) Mayfly Nymph

View 6 PicturesThis was the only Rhithrogena specimen in a large sample of nymphs from a small Catskill stream. It looks virtually identical to Rhithrogena impersonata specimens collected in the Midwest, but I didn't get to check the distinguishing features under a microscope.

Collected April 19, 2006 from Mongaup Creek in New York
Added to Troutnut.com by Troutnut on April 21, 2006

Rhithrogena morrisoni (Western March Brown) Mayfly Nymph

View 4 PicturesSize - (excluding tails) - 12 mm
Status at time of photo - preserved, but photographed within days of capture.

W. C. Day, Aquatic Insects of California differentiates morrisoni nymphs by submedian pale dots on tergites (

One tergite of this Isonychia bicolor mayfly spinner is highlighted in red.

Tergite: The top (dorsal) part of a single segment on an insect's abdomen when it consists of a single chitinous plate (sclerite), or an individual sclerite if the segment has more than one.) 8 & 9, which look to be in evidence. This is one of the "super-hatches" on this river that can be prolific March through April.

Entoman

Collected March 3, 2011 from the Lower Yuba River in California
Added to Troutnut.com by Entoman on November 1, 2011

Rhithrogena virilis Mayfly Spinner

View 2 PicturesBefore I reared this specimen the nymphs were unknown. See Western North American Naturalist for the paper on the description of this species' nymph.

Collected April 4, 2007 from the Big Thompson River in Montana
Added to Troutnut.com by Bnewell on June 26, 2011

Male Rhithrogena morrisoni (Western March Brown) Mayfly Spinner

View 2 Pictures

Collected April 20, 2012 from the Touchet River in Washington
Added to Troutnut.com by Bnewell on April 21, 2012

Male Rhithrogena Mayfly Dun

View 2 Pictures

Collected May 27, 2005 from the Vermillion River in Montana
Added to Troutnut.com by Bnewell on June 28, 2011

Male Rhithrogena undulata (Small Western Red Quill) Mayfly Spinner

View 13 PicturesThis male was collected at the same time as this female and is likely the same species.

It keys pretty clearly to Rhithrogena undulata using the key in Traver 1935, although the size is larger than expected for that species in that source.

Collected July 1, 2019 from the Madison River in Montana
Added to Troutnut.com by Troutnut on July 18, 2019

Rhithrogena virilis Mayfly Nymph

View 1 PicturesA photo showing the minor details on the nymph of this rarely collected mayfly

Collected November 30, 1999 from the Big Thompson River in Montana
Added to Troutnut.com by Bnewell on June 26, 2011

Male Rhithrogena morrisoni (Western March Brown) Mayfly Adult

View 1 Pictures

Collected May 2, 2011 from the Touchet River in Washington
Added to Troutnut.com by Bnewell on June 27, 2011

Rhithrogena Mayfly Nymph

View 1 PicturesBased on the lack of coloration and the two bars on the last tergite (

One tergite of this Isonychia bicolor mayfly spinner is highlighted in red.

Collected May 12, 2005 from Hungry Horse Creek in Montana
Added to Troutnut.com by Bnewell on June 28, 2011

Rhithrogena Mayfly Nymph

View 1 Pictures

Collected May 12, 2005 from Hungry Horse Creek in Montana
Added to Troutnut.com by Bnewell on June 28, 2011

Specimen Page:123 4

Jargon Defined:

Nymphs: The juvenile, underwater stages of mayflies, stoneflies, dragonflies, and damselflies and other aquatic insects whose juvenile stages are covered by hard exoskeletons. The word can also refer to the fishing flies which imitate these creatures, in which case it is used as a blanket term for flies imitating any underwater stage of an invertebrate (except for crayfish and leeches).

One tergite of this Isonychia bicolor mayfly spinner is highlighted in red.

Tergites: The top (dorsal) part of a single segment on an insect's abdomen when it consists of a single chitinous plate (sclerite), or an individual sclerite if the segment has more than one.

Useful References:

Arbona, Fred Jr. 1989. Mayflies, the Angler, and the Trout. Nick Lyons Books.

Caucci, Al and Nastasi, Bob. 2004. Hatches II. The Lyons Press.

Knopp, Malcolm and Robert Cormier. 1997. Mayflies: An Angler's Study of Trout Water Ephemeroptera . The Lyons Press.

Leonard, Justin W. and Fannie A. Leonard. 1962. Mayflies of Michigan Trout Streams. Cranbrook Institute of Science.