Анотація:
The genus under consideration· is accepted here in the· widest sense and contains all Baetidae species with inert bordered nymphal gills and rudimentary imaginal penis.
Following Palearctic subgenera 'are recognized under nymphal characters: -Baelis s. sir. (type-species: Ephemera fuscata L:, 17(>1), Nigrobaetis subg. n. (type-species: Ephemera nigra L., 1761), Takobia subgea. n. (type-species: Centroptilum maxillare B r a) a sch et So Id an, 1983), Labiobaetis subg. n. (type-species: Baetis atrebatinus Ea ton, 1870). Acentrella Bengt s son, 1912 (type-species: Acentrella lapponica Bengtsson, 1912), Baetiella Ueno, 1931 (type-species: Acentrella japonica Im an is hi, 1931).
B. (L.) desertus sp. n. (type-locality: Kazakhstan, river Chu) is described. B. (B.) muchei (B r a as ch, 1978) is redcscribed after male and female imago. The close relationship of
subgenera Nigrobaetis and Takobia and their intermediate position between Baelis s. slr and Cloeonidae are suggested.