The new genus Aethodelphax gen. nov. is described to include one new species, Aethodelphax prairianus sp. nov. and 7 species transferred from Delphacodes: Aethodelphax aetocephalus (Beamer, 1948), comb. nov., A. alatus (Beamer, 1948), comb. nov., A. caninus (Beamer, 1947), comb. nov., A. concavus (Beamer, 1948), comb. nov., A. megadontus (Beamer, 1951), comb. nov., A. paraparvulus (Beamer, 1948), comb. nov., and A. sagittatus (Beamer, 1947), comb. nov. A diagnosis for all species, illustrations and an identification key is provided. All species are found in the midwestern and southeastern states of the U.S., except A. caninus which is recorded from Arizona and New Mexico, and are all associated with native grasslands.