Key to Vietnamese genera of the subfamily Ponerinae based on the worker caste

The key includes Bothroponera, Pseudoponera, Emeryopone and Myopias, which have wide distributions in the Oriental region, but are not yet recorded from Vietnam.

1 Mandible long and straight, inserted in middle of anterior margin of head (Fig. 23); girdling constriction between abdominal segments III and IV very weak (Fig. 24)................................................................... 2

- Mandible triangular or rarely elongate, but always inserted at anterolateral corner of head (Figs. 25, 26, 78, 79); girdling constriction between abdominal segments III and IV usually pronounced (Fig. 27).................................... 3

2 A pair of dark lines (dl in Fig. 28) present on posterior face of head; the lines meet together at or near the dorsalmost part of preoccipital carina (oc); vertex with a median longitudinal carina (mlc) which meet preoccipital carina...... Odontomachus

- A pair of dark lines absent on posterior face of head inside preoccipital carina (oc in Fig. 29); vertex without a median longitudinal carina.................................................................................. Anochetus

3 Frontal lobes broadly separated by posteromedian portion of clypeus (Fig. 30); metatibia 2 pectinate spurs spurs (Fig. 31).... Platythyrea

- Frontal lobes narrowly separated by posteromedian portion of clypeus or otherwise closely approximated (Fig. 32); metatibia with only 1 simple or pectinate spur, or with a large pectinate spur and a much smaller simple spur (Figs. 33, 34)......... 4

4 Mandible with an elongate and linear blade which has two rows of many small teeth (Fig. 25); ventral part of base of each mandibular blade forming a large triangular flange................................................ Harpegnathos

- Mandible variable in shape but never with blade as above (Figs. 26, 78, 79)...................................... 5

5 Anterior clypeal margin armed with a series of distinct teeth (Fig. 35); each humerus (dorsolateral part of pronotum) forming a distinct process (Fig. 36)..................................................................... Odontoponera

- Anterior clypeal margin without a series of distinct teeth (Fig. 37), but often with a median emargination or tooth/process; each humerus (dorsolateral part of pronotum) never forming a distinct process (Fig. 38)................................. 6

6 Posterodorsal margin of petiolar node armed with a pair of acute spines (Fig. 39); a conspicuous excavation present above mesopleuron (Fig. 40) (in ergatoid queen the excavation filled with a substance called gemma)................ Diacamma

- Posterodorsal margin of petiolar node usually unarmed (Fig. 41), or sometimes with three or more dents or rarely with a single median prominence, but never armed with a pair of acute spines; a conspicuous excavation absent above mesopleuron (Fig. 42)................................................................................................ 7

7 Inner margin of pretarsal claws of hind leg armed with 1 to many teeth (Fig. 43); median portion of clypeus well produced anteriad (Fig. 44)............................................................................. Leptogenys

- Inner margin of pretarsal claws of hind leg without teeth (Fig. 45); median portion of clypeus usually weakly produced (Fig. 46), but sometimes forming a conspicuous projection (Fig. 78)................................................. 8

8 Dorsal (outer) surface of mesotibia with peg-like or spiniform setae among background pilosity (Fig. 47)............... 9

- Dorsal surface of mesotibia without peg-like or spiniform setae (Fig. 48) (dorsal surface of mesotibia sometimes with a few stout setae near tarsus but not extending along length of tibia, and/or sometimes with relatively long and thick standing setae scattered among background pilosity).................................................................... 10

9 Basal portion of mandible with a distinct circular fovea or elongate depression dorsolaterally (Fig. 49)......... Cryptopone

- Basal portion of mandible without a circular fovea or elongate depression dorsolaterally (Fig. 50)........... Centromyrmex 10 Apex of metatibia ventrally with a large pectinate spur, but without a smaller, simple spur in front of the pectinate spur (Fig.