Key to Tricosa species (females only)

1 Elytral discal striae and interstriae clearly uniseriate punctate.................................................. 2

- Elytral discal striae and interstriae punctures confused........................................................ 4

2 Pronotum anterior margin unarmed, protibia broad, appearing distinctly triangular......................... jacula sp. n.

- Pronotum anterior margin serrate, protibia narrow, appearing obliquely triangular.................................. 3

3 Smaller size, 2.40–2.50 mm and declivial interstriae moderately setose........................... metacuneola (Eggers)

- Larger size, 3.80 mm and declivital striae and interstriae densely setose.......................... mangoensis (Schedl)

4 Pronotum anterior margin armed by a row of six serrations. Smaller, 2.70–3.10 mm long, and stouter 2.50–2.70 times as long as wide................................................................................ cattienensis sp. n.

- Pronotum anterior margin armed by a row of eight serrations. Larger, 3.20–3.40 mm long and more slender, 2.83–2.91 times as long as wide.......................................................................... indochinensis sp. n.