Key to Polyrhachis, subgenus Campomyrma, from Thailand and Laos

Key to Thai and Lao species of Polyrhachis, subgenus Campomyrma, based on workers (modified from Jaitrong et al., 2023).

1

 * Petiole without distinct dorsolateral spines (Fig. 1D) Polyrhachis sukarmani


 * Petiole with distinct dorsolateral spines (Fig. 1A–C)

2

 * Dorsum of petiole with four long spines (Fig. 1A); vertex and gastral tergites II–IV without erect hairs; propodeal spine relatively long, longer than wide at base; antennal scape shorter than or about as long as head width Polyrhachis quadrispinosa


 * Dorsum of petiole with two acute spines projecting posterolaterally and two denticles in between (Fig. 1B–C); vertex with two erect hairs but pilosity on gastral tergites variable; propodeal spine relatively short, shorter than wide or almost as long as wide at base; antennal scape longer than head width

3

 * Mesonotum longer than broad; propodeal spine posteriorly directed with apex slightly up curved; pair of median denticles on dorsum of petiole rudimentary with round apices; first gastral tergite without erect hairs; in dorsal view, propodeal dorsum deeply concave Polyrhachis lao


 * Mesonotum broader than long; propodeal spine upward-directed; pair of median denticles on dorsum of petiole distinct with acute apices; first gastral tergite with sparse erect hairs; in dorsal view, propodeal dorsum only shallowly concave Polyrhachis halidayi