Mayfly Species Rhithrogena virilis

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 virilis

Pictures Below ↓

Pictures of 5 Mayfly Specimens in the Species Rhithrogena virilis:

Specimen Page:12

Male Rhithrogena virilis Mayfly Spinner

View 12 PicturesI'm fairly sure this is a specimen of Rhithrogena virilis based on closeup examination of the reproductive anatomy under the microscope (not shown in photos). The other other species of Rhithrogena this large is Rhithrogena flavianula, but the key in Needham's Biology of Mayflies mentions annulation in the abdomen (visible in some images on bugguide.net) more distinct than that on this specimen.

The body and front wing were both about 15.5 mm long, while the cerci (Cercus: The left and right "tails" of an insect are known as the cerci or caudal cerci. The middle tail of a three-tailed insect is not.) were 40 mm long.

Collected July 5, 2017 from the South Fork Sauk River in Washington
Added to Troutnut.com by Troutnut on July 6, 2017

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

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

Specimen Page:12

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Jargon Defined:

Abdomen: The rear and usually the longest (ten-segmented in mayflies) portion of an insect's body, to which the tails are attached.

Cerci: The left and right "tails" of an insect are known as the cerci or caudal cerci. The middle tail of a three-tailed insect is not.

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).