Stoneflies - Plecoptera: Chloroperlidae of Gunnison County, Colorado
Nymph key to Genera

Mature nymphs only!
Updated 28 March 2005                
1a. Eyes small and set far forward on head; margin of head behind eye forms a right angle; body very elongate.

1b. Eyes large, set farther back; margins of head rounded; body less elongate.

2a. Lacinia of maxilla terminating in a large single tooth; pronotal setae sparsely clustered or single and restricted to corners; numerous intrasegmental hairs on cerci.

2b. Lacinia of maxilla terminating in a single large and a single small tooth; marginal hairs of pronotum numerous at least on anterior and posterior margins; intrasegmental hairs absent from cerci.

3a. Thick, depressed black hairs laterally on sides of all thoracic sterna.

Obvious darkly "hairy chest"

3b. Thoracic hairs erect and light colored.
4a. Marginal hair fringe of pronotum sparse or absent laterally, not uniform; short hair fringe on posterior margins of abdominal terga not regular or uniform; long fine hairs of cerci shorter than cercal segments; abdomen concolorous or with pale longitudinal median stripe.

There are no keys to nymphs yet.

4b. Marginal hair fringe of pronotum thick, regular, uniform, nearly complete or sparse only on lateral margins; short hair fringe on posterior margins of abdominal terga uniform and thick; long fine hairs of cerci longer than cercal segments; abdomen nearly all one color or with pale checkered pattern.
5a. Abdomen distinctly striped; pronotal hair fringe regular and nearly complete; inner margins of wingpads widely oblique.
5b. Abdomen concolorous; pronotal hair fringe sparse laterally; inner margins of wingpads slightly oblique.


Figures redrawn from reviewing both of the following publications:

Surdick,RF 1985: Nearctic Genera of Chloroperlinae (Plecoptera:Chloroperlidae). University of Illinois Press, Urbana, IL. 146 pages.

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.

Good Links

Key to Male Chloroperlidae
Key to Female Chloroperlidae
Brown, Wendy S. 2004 Plecoptera or Stoneflies of Gunnison County, Colorado