Key to Terthrothrips species from China

1. Pronotal anteromarginal setae well developed, expanded at apex; anteroangular setae vestigial; mesopresternum reduced to pair of triangles laterally; pelta hat-shaped with distinct lateral lobes................................ T. palmatus sp. n.

-. Pronotal anteromarginal setae reduced..................................................................... 2

2. Pronotal anteroangular setae vestigial; metanotal median pair of setae reduced, about 10 microns; pelta trapezoidal, without lateral lobes.................................................................................. T. apterus

-. Pronotal anteroangular setae well developed; metanotal median pair of setae longer than 20 microns; pelta hat-shaped, with lateral lobes..................................................................................... T. parvus