|1a. Occiput with transverse row of evenly spaced spinules; Abdominal terga with numerous spinules.|
|1b. Occiput with sinuate or incomplete row of spinules; Abdominal terga without spinules.|
|2a. Occiput with sinuate and irregularly spaced row of spinules; Abdominal terga with few or no intercalary spinules.|
|2b. Occiput with few scattered spinules near the post ocular fringe; Cerci with long fringe of silky setae.
Only a few scattered spinules behind the eyes. The longer setae (hairs) by the eye are the "postocular fringe". All our perlids have a postocular fringe so its not useful for separating the species.
ReferencesKeys and illustrations modified from the following:
Stark,BP; Gaufin,AR 1976 The nearctic genera of Perlidae (Plecoptera). Miscellaneous Publications of the Entomological Society of America 10, 1-80.
Baumann,RW; Gaufin,AR; Surdick,RF 1977 The stoneflies (Plecoptera) of the Rocky Mountains. Memoirs of the American Entomological Society 31, 1-208.
Good LinksKey to Perlidae Females
Key to Perlidae Males