Key to the Palearctic and Micronesian species of Rainieria

1. Male sternite 5 elongate, area excluding the fork twice as long as the genital fork—[Japan (Ogasawara Islands)]........................................................................................ boninensis (Hennig, 1935)

- Male sternite 5 stout, area excluding the fork shorter or about as equal to the length genital fork (Fig. 5)................ 2

2. Mid and hind femora yellowish brown, with black ring of approximately 1/5 the length of femora at the apical 3/4 portion; wings uniformly infuscate, with faint discal band—[China (Southwest), Taiwan]............... leucochira Czerny, 1932

- Mid and hind femora predominantly dark brown, with yellowish brown preapical ring (Fig. 3)........................ 3

3. Wings evenly infuscate, without dark discal band; basal half of mid- and hind femora gradually transitioning into lighter brown; extreme base of mid- and hind tibia without yellowish brown ring [Europe (Central, East)].......... latifrons (Loew, 1870)

- Wings evenly infuscate with dark discal band; extreme base of mid- and hind femora often with a yellowish brown ring... 4

4. Short stout setae of the male sternite 5 varying in length, most long at the basal 1/4 region of the arm and gradually shortened to the apical portion of arm—[Russia (Far East), Japan (Honshu)].............. hennigi Krivosheina & Krivosheina, 1996

- Short stout setae of the inner side of arm in male sternite 5 uniform in length...................................... 5

5. Male sternite 5 with slightly incurved arm (fig. 5A), female sternite 3 – 4 strongly reduced (fig. 6C–D); pleural membrane uniformly dark brown with distinct triangular white region below T 3–4 in female—[China (Northeast), South Korea].................................................................................... triseta Li, Liu & Yang, 2012

- All female sternite well developed (Fig. 6A–B); pleural membrane uniformly dark brown (Fig. 3A–B, E–F)............. 6

6. Hind tarsus uniformly dark brown; male sternite 5 with short stout setae of inner arm uniformly distributed, basal cleft triangular (Fig. 5B); epandrium relatively stout; phallic bulb almost reaching the base of epandrium; tip of distal distiphallus blunt (Fig. 5E)—[South Korea]........................................................... tenebrosa Kim & Lee sp. nov.

- Hind metatarsus white, hind tarsus otherwise dark brown; male sternite 5 with short stout setae of inner arm sparsely distributed in the middle, basal cleft significant (Fig. 5C); epandrium elongate; phallic bulb only reaching the middle half of the epandrium; tip of distal distiphallus distinctly sharp distally (Fig. 5F)—[Europe (Central, East, West, North, South)]... calceata (Fallén, 1820)