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Ephemeroptera: Heptageniidae of Gunnison County, Colorado

Adult key to Genera
Red Quills, Cahills, Quill Gordons

Most of these genera do not have keys yet so the link goes to an introduction for the genera.

1a. Femora ususally with dark longitudinal streak near middle. Stigmatic area of wing with two to many anastomoses of crossveins. Basal segment of foretarsi less than or equal to one-third the length of segment 2.
1b. Femora usually without dark streak.Stigmatic area of wing with or without anastomosed crossveins. If crossveins anastomosed, basal segment of fore tarsi equal or longer to half of segment 2.

2a. Foretarsal segment 1 equal or longer than segment 2.
2b. Foretarsal segment one 4/5ths or less than segment 2.

3a. Penis lobes separated or appearing separated to near base medially. Basal segment of foretarsi usually 2/3 or more the length of segment 2.
3b. Penis lobes fused medially at least in basal half. Basal segment of foretarsi 2/3 or less the length of segment 2, usually less than half the length of segment 2.

4a. Eyes of male meeting on vertex or separated by less than the diameter of the median ocellus.
4b. Eyes of males separated dorsally by at least the width of one lateral ocellus.


Waltz,RD; Burian,SK 2008 Ephemeroptera. In: An Introduction to the Aquatic Insects of North America. 4th ed. Eds: Merritt,RW; Cummins,KW; Berg,MB Kendall/Hunt Publishing Company, Dubuque, Iowa, 181-236.

Brown, Wendy S. 2004 Mayflies (Ephemeroptera) of Gunnison County, Colorado, USA