1 T 2 partially and slightly sculptured; propodeum evenly rugose on its entire surface, without distinctive carination [western Palaearctic region: Austria (Tirol, 2400m)]......................................... Paroplitis rugosus Papp, 1991
- T 2 mostly smooth and shiny (Figs 8, 15, 19); propodeum only partially rugose, with median carina visible on at least anterior 0.5, and sometimes with complete or partial transverse carina (Figs 7, 8, 15, 19)................................... 2
2 (1) Fore wing areolet quadrangular and relatively large, its maximum height 1.1 x vein r length (Fig 5); fore wing with vein 2 CUa tubular on its anterior 0.3–0.5 [Nearctic region: Canada (British Columbia, Yukon) and United States (Alaska)]................................................................................... Paroplitis beringianus Mason, 1981
- Fore wing with areolet triangular and relatively small, its maximum height at most 0.7 x vein r length, usually much less (Figs 10, 12, 17); fore wing with vein 2 CUa entirely nebulous [western Palaearctic or Oriental regions]..................... 3
3 (2) Propodeum usually without trace of transverse carina (Fig. 19); fore wing with areolet very small, its maximum height 0.2 x vein r length, its maximum width 0.2 x vein r length (Fig. 17) [western Palaearctic region: Azerbaijan, Belgium, Finland, France, Germany, Hungary, Poland, Romania, Russia (Krasnodar Kray), Sweden, Switzerland, Ukraine, United Kingdom]........................................................................... Paroplitis wesmaeli (Ruther, 1860)
- Propodeum with a more or less complete and defined transverse carina (Fig 15); fore wing with areolet larger, its maximum height 0.5–0.7 x vein r length, its maximum width 0.6–0.7 x vein r length (Figs 10, 12) [Oriental region, between 1700–2400 m]................................................................................................ 4
4 (3) Scape, tegula, humeral complex, and legs entirely yellow (except for anterior 0.5–0.7 of metacoxa which is brown) (Fig. 9); fore wing with vein R 1 as long as or longer than pterostigma length, and much longer than distance delimited between end of vein R 1 and end of vein 3 RSb (Fig. 10) [Oriental region: Philippines (Luzon Island) and southern Vietnam (Lam Dong)]............................................................................. Paroplitis luzonicus Mason, 1981
- Scape, tegula, humeral complex, and most of legs entirely brown to dark brown (Figs 11–15); fore wing with vein R 1 shorter than pterostigma length and same length (at most slightly larger) than distance delimited between end of vein R 1 and end of vein 3 RSb (Fig. 12) [Oriental region: northern Vietnam (Tonkin)]........................................................................................ Paroplitis vietnamensis van Achterberg and Fernández-Triana new species