Aquatic Insects of Michigan

by Ethan Bright, Museum of Zoology Insect Division and School of Natural Resources and Environment
University of Michigan

Ephemerellidae of Michigan - Identification

[under construction]

Key to the Adult Ephemerellidae of Michigan

1a	a. Adult and subimago with vestiges of gill sockets on Ab3	2
	b. Eggs with one polar cap and somewhat smooth chorion
1b	a. Adult and subimago without vestiges gill sockets on Ab3	4
	b. Eggs without polar caps, eggs with two polar caps, or if eggs with one polar cap then with reticulate chorion
2a(1a)	a. Terminal segment of male genital forceps more than twice as long as broad	Drunella
	b. Inner margin of lone second segment distinctly incurved or strongly bowed
2b	a. Terminal segment of male forceps less than twice as long as broad	3
	b. Inner margin of long second segment variable but not strongly bowed
3a(2b)	a. Penes with dorsal and/or ventral spines and shaped similar to figure, or with long anterolateral lobes	Ephemerella
3b	b. Penes different than above, with lateral subapical projections	Serratella
4a(1b)	a. Ab6-7 of adult and subimago with poorly developed fingerlike remnants of posterolateral projections	Attenella
	b. Male adult with terminal segments of genital forceps relatively elongate (approximately six times as long as broad)
	c. Eggs without polar caps and having somewhat smooth chorion
	a. Ab7 and, often, preceding segments also, of adult and subimago with well-developed fingerlike remnants of posterolateral projections	5
	b. Gill socket formation of Ab4 relatively well developed
	c. Male adult with terminal segment of genital forceps relatively short (length always less than three times width)
	d. Egg with reticulate chorion and zero, one, or two, polar caps
5a(4b)	a. Male with penes broadest at base, narrowing apically	Eurylophella
	b. Eggs of known species without polar caps
5b	a. Male with penes laterally expanded apically, somewhat narrower basally	Timpanoga
	b. Eggs with polar caps

1a	a. Lamellate gills present on Ab3-7	2
1b	a. Lamellate gills present on Ab4-7	4
2a(1a)	a. Leading margin of fore-femora armed with conspicuous tubercles	Drunella Needham
2b	a. Leading margin of fore-femora without such tubercles	3
3a(2b)	a. Caudal filaments with or without whorls of spines at the apex of each segment, apical half of caudal filaments with long intersegmental setae extending laterally	Ephemerella Walsh
	b. Maxillary palps well-developed, usually 2/3x or more the length of the galea-lacina
3b	a. Caudal filaments with whorls of spines at the apex of each segment, otherwise with only sparse setae or none	Serratella Edmunds
	b. Maxillary palps reduced to one-half or less the length of the galea-lacinia
4a(1b)	Gills on Ab4 tergum not operculate, apical half of gills on Ab5-6 visible and not reaching the posterior margin of Ab7	Attenella
4b	Gills on Ab4 tergum operculate, largely covering those on Ab5-7, only about 1/3 of any following gill visible, and reaching to about the posterior margin of Ab7 tergum	5
5a(4b)	a. Claws without denticles	Timpanoga Needham
	b. Maxillae with palpi
	also: Filamentous gills on Ab1 originate sublaterally on tergum; posterolateral abdominal processes well-developed
5b	a. Claws with denticles	Eurylophella Tiensuu
	b. Maxillae without palpi
	also: Paired tubercles present on Ab5-7 terga; Ab9 terga ca. 1.4x the midlength of Ab8 or Ab10; operculate gills relatively narrow, ovate and broadly rounded distally