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Stoneflies - Plecoptera: Nemouridae of Gunnison County, Colorado
Male key to Genera

1a. Paraprocts divided into 3 lobes with spines or prongs on middle or outer lobes.
1b. Paraprocts single or divided into 2 lobes; no spines on outer lobes.
2a. Cervical gills branch from base at the neck; mesobasal lobe absent.
2b. Some cervical gills branch midway out their length; mesobasal lobe present at base of cerci in dorsal aspect.

(Gills have a Y-shape)

3a. Lateral knobs present at basal corners of epiproct; basal cushion present at dorsal base of epiproct; cervical gills present.
3b. Lateral knobs absent; basal cushion absent.
4a. Dorsal sclerite of epiproct large and lateral arms well developed.
4b. Dorsal sclerite of epiproct reduced in size and lateral arms poorly developed.
Prostoia besametsa

Good Links

Key to Nemouridae nymphs of Gunnison County
Key to Nemouridae Females of Gunnison County


Keys 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.
Brown, Wendy S. 2004 Plecoptera or Stoneflies of Gunnison County, Colorado

Updated 2May2004