Stoneflies - Plecoptera: Chloroperlidae of Gunnison County, Colorado
Adult Male Key to Genera

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 convex; body less elongate.

2a. Epiproct large, its tip variously sculptured and hinged; brush of setae on posterolateral margins of terminal segments.
2b. Epiproct small, about as wide as long; tip tab-like or button-like, not hinged; no brushes on terminal segments.
3a. Darker pigmented with various pronounced brown or black markings on head or pronotum, dark abdominal stripe; sutures darkly marked; transverse ridge present on tergum nine; epiproct tip usually extending anteriorly beyond tergum ten.

3b. Paler-pigmented with pale dusky or no markings on pronotum; Dark marking on head; sutures not darkly marked; transverse ridge absent on tergum nine; epiproct tip usually not extending anteriorly beyond tergum nine
4a. Fingerlike process at base of cerci; epiproct tip button-like.

4b. No process at base of cerci; epiproct tip tab-like

5a. Aedeagus terminating in a pair of thin, feathery processes; hammer absent; body pale and unpatterned.

5b. Aedeagus lacking thin feathery processes; hammer present; body darkly patterned.



Keys and illustrations modified from the references:
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 Chloroperlidae Females of Gunnison County
Key to Chloroperlidae Nymphs of Gunnison County
Brown, Wendy S. 2004 Plecoptera or Stoneflies of Gunnison County, Colorado