Acentrella	mature larva (nymph) - male Copyright © 2009 Tom Murray	subimago (dun) - female Copyright © University of Guelph Insect Collection imago (spinner) - male Copyright © 2011 Bob Newell imago (spinner) - female Copyright © 2011 Tom Murray
Acentrella	Body somewhat flattened; paired dark dorsal spots on abdomen; prominent fringe of long setae on femur, tibia, and tarsi; very short middle tail w/fewer than 5 segments.	.
Acentrella insignificans
	Mature nymph w/large hind wing pads; common east of Cascades.	.
Acentrella turbida (Minute Gray-winged Brown; Little Slate-winged Brown Quill. )
	Body stout & chunky; abdomen pale olive with tergites 1-8 dark olive; mature nymph w/ltiny hind wing pads; common east of Cascades.	Forewing with paired marginal veinlets.

Baetis (Blue-winged Olive; Blue-winged Olive Dun; Blue Wing; BWO; Little Iron Blue Quill; Little Brown Quill; Little Blue-winged Olive; Rusty Spinner; Tiny Olive. )	mature larva (nymph) - male Copyright © 2009 Tom Murray	subimago (dun) - Female Copyright © 2010 Tom Murray imago (spinner) - male Copyright © 2012 John Barry
Baetis	Single plate-like gills on abdominal segments 1-7.	Hind wing exhibiting a pointed costal angulation; double intercalary veins.
Baetis alius
	Cold water taxa with a longer body and maxillary palps that are not mitten-shaped.	.
Baetis bicaudatus (Light Rusty Spinner; Pale Olive Dun. )
	Abdomen medium brown w/tergites 1-10 pale in color; dark markings on segs. 3,4,7; veinlets indistinct.	.
Baetis brunneicolor
Baetis flavistriga (Dark Blue-winged Olive; Dark Gray-winged Olive; Dark Gray-winged Olive Dun; Minute Blue-winged Olive; Little Slate-winged Brown Quill; Dark Olive Brown Spinner. )
	Middle tail less than 1/2 length of others; tail bands at middle & tip; abdominal tergites 5, 9-10 pale.	.
Baetis notos
Baetis tricaudatus (Light Rusty Spinner; Light Blue Dun; Iron Blue Quill; Little Iron Blue Quill; Rusty Spinner; Dark Rusty Spinner; Light Rusty Spinner. )
	Body medium olive brown to dark olive w/faint dorsal stripe; tails: middle tail < 1/2 length others; gills veination conspicuous; rounded 7th gill.	Body olive brown to dark brown; wings light to medium gray; length 8-9/4-6 mm.; 2 tails; emerges Oct15-Nov, Feb-Mar.

Diphetor (Blue Wing; BWO; Blue-winged Olive; Tiny Olive. )	nymph (larva) - female Copyright © 2012 Donald S. Chandler	subimago (dun) - male Copyright © 2010 Phil Huntley-Franck subimago (dun) - female Copyright © 2012 Donald S. Chandler imago (spinner) - male Copyright © 2011 Judy Gallagher imago (spinner) - female Copyright © 2012 Donald S. Chandler
Diphetor	Relatively long and thin body; uniformly brown in color; bases of antennae very close together viewd straght-on; three tails of similar length; no villopore near bases of legs; gills on abdominal segments 2-7, simple.	.
Diphetor hageni (Iron Blue Qulll; Little Iron Blue Quill; Dark Brown Dun; Dark Brown Spinner. )
	Keeled head; relatively long and thin uniformly brown body; bases of antennae very close together viewd straght-on; ab/ segs. 4-5, 9-10 pale; single plate-like gills on ab. segs. 2-7, veinlets indistinct; middle tail greater than 3/4 length others.	Body light olive to dark brown; wings gray to dark gray; length: 5-7 mm.; 2 tails; emerges mid-Mar thru Apr, Jun-mid Aug, mid-Sep thru Oct.

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.