|1a. Cervical gills present.|
|1b. Cervical gills absent.|
|2a. Cervical gills highly branched.|
|2b. Cervical gills simple, never more than four branches.
Nemourinae (in part) Zapada
|3a. Some cervical gills branch midway out their length; Eight sternum sclerotized along median notch only.
(Gills have a Y-shape)
|3b. Cervical gills branch from base at the neck; Eighth sternum with sclerotized vaginal lobes.|
|4a. Eighth sternum with distinct sclerotized median stripe.|
|4b. Eight sternum without distinct sclerotized pattern.|
Good LinksKey to Nemouridae Nymphs
Key to Nemouridae Males
ReferencesKeys and illustrations from the following publications were altered to construct this key:
Baumann,RW; Gaufin,AR; Surdick,RF 1977 The stoneflies (Plecoptera) of the Rocky Mountains. Memoirs of the American Entomological Society 31, 1-208.
Stewart,KW; Harper,PP 1996: Plecoptera. In: An Introduction to the Aquatic Insects of North America. 3rd ed. Eds: Merritt,RW; Cummins,KW Kendall/Hunt Publishing Company, Dubuque, Iowa, 217-266.
Ward,JV, Kondratieff,BC and Zuellig,RE 2002: An Illustrated Guide to the Mountain Stream Insects of Colorado. 2nd ed. University Press of Colorado, Boulder, Colorado. 219 pages.