Baetis spp. Key to Baetis spp. Couplet 1The separation of species in this genus offers considerable difficulty even in the case of males (for which this key is intended), as the characters used are not frequently subject to variation in individuals. The production of a satisfactory key to females and subimagines must await further study.
1. Second longitudinal vein in hind wing not forked (fig 23) (exceptionally so in Baetis buceratus (Eaton)).
2. Second longitudinal vein in hind wing forked (fig 28).
