WA Mayfly Descriptions

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Flyfishing Entomology

WA Mayfly Description

Taxonomic Name (Common Name)	Larva (Nymph)	Subimago (Dun) Imago (Spinner)
Ephemerellidae (Spiny Crawler Mayfly )	Diverse shapes and sizes, but usually robust, sometimes flattened, often with tubercles or spines; always with 3 tails; wholly dorsal gills (never on Ab2) which slightly overlap and undute sequentially.	3 tails; pronounced angle on fore margin of hind wings; short unattached intercalary veins on outer margin of FW.

Taxonomic Name
(Common Name)

Larva (Nymph)

Subimago (Dun)
Imago (Spinner)

Attenella

subimago - female

Attenella

Tarsal claws w/denticles; gills start on abdominal segment 4, all similar in size; gills on ab. seg. 4 not (or partially) covering succeeding pairs, paired dorsal tubercles present on ab. segs.; all femora similar; all tails similar.

Terminal segment of claspers 6x as long as broad.

Attenella delantala

larva (nymph)

Blunt, rounded tubercles that curve outward on top of abdominal segments 4-8; tubercles on segment 8 are particularly broad and give that part of abdomen a flattened, platform appearance.

Attenella margarita
(Little Western Blue-winged Olive; Little Blue-winged Olive; Small Blue-winged Olive; Margaret's Mayfly. )

larva (nymph)

subimago (dun) - female

Small, slightly pointed tubercles on abdominal segments 3-9; abdominal segments 4,5 & 8 pale.

Body medium olive; wings medium gray; length: 6 mm.; 3 tails; emergences Aug 1 - Sep 10.

State of Washington distribution is based on:
Mayflies (Ephemeroptera) of the far western United States (Part I: Washington) by M. D. Meyer & W. P. McCafferty,
and augmented by A DNA Barcode Library for North American Ephemeroptera: etc. by Webb, Jacobus, Funk, et. al.

Created: 08/16/2013 Last modified: 12/07/2014 www.FlyfishingEntomology.com