A REVISION OF THE NEARCTIC AMELETUS MAYFLIES BASED ON ADULT MALES, WITH DESCRIPTIONS OF 7 NEW SPECIES (EPHEMEROPTERA, AMELETIDAE)

A systematic revision of North American species of the genus Ameletus, excluding parthenogenetic species, is presented. Seven new species ar e described (A. andersoni, A. bellulus, A. doddsianus, A. edmundsi, A. majusculus, A. pritchardi, and A. tolae), separate keys are given to western and eastern species, annotated accounts of all 30 presently re cognized bisexual species are provided, taxonomic characters are illus trated, and distribution data are presented for all species. The follo wing nomenclatural changes are proposed: Ameletus aequivocus is consid ered a junior synonym of A. sparsatus; A, alticolus and A, celeroides junior synonyms of A. celer; A. connectina and A. connectus junior syn onyms of A. velox; A. facilis a junior synonym of A. vancouverensis; A . monta a junior synonym of A. similior; A. querulus a junior synonym of A. shepherdi. The specific status of A. tuberculatus is questioned and it is provisionally considered to be the same as A. celer.