Key to Vietnamese Acropimpla species

1. Propodeum without or with short stub of median longitudinal carina............................................. 2

-. Propodeum with median longitudinal carina distinct present.................................................... 4

2. Face black with two small yellow spots below antennal sockets (Fig. 4 d); metasomal tergites black, each with two yellow apicolateral spots (Fig. 4 a); ovipositor 2.80 times as long as hind tibia length........................... A. lampei sp. nov.

-. Face yellow with or without black mark; metasomal tergites with black and yellow bands............................ 3

3. Face with median black mark, clypeus yellow (Fig. 2 c); tergite 5 entirely black (Fig. 2 a); ovipositor 2.50 times hind tibia length................................................................................................................................................................................ A. leucostoma (Cameron)

-. Face yellow, clypeus black (Fig. 1 b); tergite 5 with basal large black and apical narrow yellow band (Fig. 1 a); ovipositor 3.0 times as long as hind tibia length............................................................ A. hapaliae (Rao)

4. Face, clypeus, scutellum, and metascutellum entirely yellow (Fig. 6 d–e); ovipositor 2.90 times hind tibia length with distinct constriction subapically (Fig. 6 g).................................................... A. phongdienensis sp. nov.

-. Face marked with black; ovipositor without distinct constriction subapically...................................... 5

5. Face with small triangular black mark connecting with black clypeus (Fig. 5 d); propodeum with polished area between median longitudinal carinae; metasomal tergite reddish with narrow black bands on first tergite basally, on second and third tergite apically (Fig. 5 a–b); ovipositor 3.10 times as long as hind tibia length.............................. A. mucronis sp. nov.

-. Face with pentagonal black mark, clypeus yellow (Fig 4 b); metasomal tergites black with yellowish apicolateral stripes (Fig. 3 a); ovipositor 2.20 times as long as hind tibia length................................ A. taishunensis Liu, He & Chen