Key to the Palaearctic species in the genus Brachyzapus

1 Propodeum with apical carina, petiolar area distinct. Hind femur slender.......................................... 2

- Propodeum without apical carina, petiolar area not limited. Hind femur variable.................................... 3

2 Flagellum with white ring. Hind femur 5.0 × as long as wide............................... B. nitidus (Hao & Sheng)

- Flagellum without white ring. Hind femur 6.0 × as long as wide.................... B. unicarinatus (Uchida & Momoi)

3 Scutellum and postscutellum yellow (Fig. 12). All tergites with distinct yellow stripes apically (Figs 8, 9).................................................................................................. B. nikkoensis (Uchida)

- Scutellum and postscutellum black. Metasomal terga entirely black or with trace of yellow stripe on tergites 3–7.......... 4

4 Face very strongly convergent down (Fig. 3), 1.9 × as long as wide. Malar space 0.15 × as long as basal width of mandible..................................................................................... B. convergens sp. nov.

- Face moderately convergent down, 1.6 × as long as wide. Malar space longer...................................... 5

5 Malar space 0.66 × as long as basal width of mandible. Scutellum weakly convex; lateral carina present at base............................................................................................... B. atripedalis Sheng

- Malar space shorter, about 0.3 × as long as basal width of mandible. Scutellum strongly convex; lateral carina extending to middle.............................................................................................. 6

6 Nervellus distinctly reclival, intercepted above middle (Fig. 35). Median dorsal carinae of first tergite short, not reaching middle of the tergite (Fig. 30).......................................................... B. pyramidalis sp. nov.

- Nervellus almost vertical, intercepted on middle. Median dorsal carinae of first tergite longer, reaching or bypass middle of the tergite............................................................................................... 7

7 Face and dorsal surface of propodeum densely punctate. Mesopleuron with epicnemal carina sinuous (Fig. 41). Mesopleural suture strongly angled. Median longitudinal carina of first tergite not extending to posterior transverse smooth band. Second tergite with low basal oblique groove. Hind wing with veins Rs, M and Cu 1 more or less pigmented (Fig. 42)......................................................................................... B. tenuiabdominalis (Uchida)

- Face and dorsal surface of propodeum polished, sparsely punctate. Mesopleuron with epicnemal carina weakly curved (Fig. 27). Mesopleural suture weakly angled. Median longitudinal carina of first tergite extending to posterior transverse smooth band. Second tergite with distinct basal oblique groove. Hind wing with veins Rs, M and Cu 1 present as traces..................................................................... B. politus Pham, Broad, Matsumoto & Wägele, 2012