COMPARISON OF THE EPIPROCT STRUCTURE OF 2 CLOSELY-RELATED SPECIES, SWELTSA-FIDELIS (BANKS) AND S-REVELSTOKA (JEWETT) (PLECOPTERA, CHLOROPERLIDAE)

The male epiprocts of 2 closely related western Nearctic species, Swel tsa fidelis (Banks) and S. revelstoka (Jewett), were examined using SE M. The males of these 2 species have been historically distinguished b y epiproct measurements. The ratio of the length from the base to grea test width versus total epiproct length ranges from 0.49 mu m to 0.87 mu m ((x) over bar = 0.56) in S. fidelis and 0.55 mu m to 0.69 mu m (( x) over bar = 0.60) in S. revelstoka. Similarities in measurement sugg est that the location of the greatest epiproct width is not a reliable and consistent character for distinguishing males of these 2 species.