Key to Rhodostrophia species of the Baikal region

1. Wings with thin purple transverse lines and discal spots (usually absent from hindwing), area between medial line and postmedial line/termen occasionally filled with purple (Figs. 19A, 58A); male hindtibia with three spurs. In male genitalia (Figs. 39D–39F) uncus broad and dilated subapically, distal margin of valva forked, not spinulose, aedeagus without cornuti; in female genitalia (Fig. 49G) apophyses posteriores and apophyses anteriores are of about equal length; signum consists of separate sclerites................................................................................. R. vibicaria (Clerck, 1759)

- Wings with dark undulate transverse fasciae (Figs. 10B, 58B); male hindtibia with four normal spurs. In male genitalia (Figs. 39A–39C) uncus very long, slightly dilated apically, valva broad, with straight spinulose distal margin, aedeagus with stout cornutus at tip; in female genitalia (Fig. 49H) papillae anales partially spinose; apophyses posteriores about three times longer than apophyses anteriores; signum large, coat-shaped................................... R. jacularia (Hübner, 1813)