Key to Chinese Bactrothrips species

1. Eyes posteriorly prolonged on ventral surface (Fig. 32)............................................. B. flectoventris

- Eyes not prolonged on ventral surface (Figs 31, 33–37)........................................................ 2

2. Sense-cones on antennal segment III well developed, longer than one third of this segment (Fig. 1)..................... 3

- Sense-cones on antennal segment III shorter than one third of this segment (Fig. 15)................................ 4

3. Tibiae largely dark brown, but yellowish at extreme bases and apices; lateral tubercles on male abdominal segment VI bicoloured, with basal 1/4 dark brown....................................................... B. elongatus n. sp.

- Hind legs bicoloured, at least distal third of hind tibiae yellowish; lateral tubercles on abdominal segment VI largely dark brown, with extreme apices yellow................................................................. B. honoris

4. Tibiae largely dark brown, with extreme bases and apices yellowish.............................. B. furvescrus n. sp.

- Tibiae distinctly bicoloured, about yellow at apical half and dark brown at basal half................................ 5

5. Interocellar setae on head the longest (Fig. 34)...................................................... B. pictipes

- Mid-dorsal setae on head the longest (Figs 31, 35)............................................................ 6

6. Postocellar setae much longer than postoculars, about 3–5 times as long as diameter of posterior ocelli........ B. brevitubus

- Postocellar setae much shorter than postoculars, about 1–1.5 times as long as diameter of posterior ocelli.................................................................................................... B. quadrituberculatus