Key and distributions to species of Yunnantettix Zheng, 1995 Fig 1

1. Vertex convex; median carina of vertex protruding forward; in lateral view vertex together with frontal costa obtusely rounded and protruding forward, face slightly oblique; pronotum a little uplifted between shoulders...........................2

- Vertex not convex; median carina of vertex not protruding forward; in lateral view vertex together with frontal costa arcuate, not protruding forward, face vertical; pronotum distinctly uplifted between shoulders................................4

2. In dorsal view anterior margin of vertex arcuate; humeral angles obtusely angled; prozonal carinae short, interhumeral carinae short. Distributed in China (Yunnan)..................................................... .. Y. bannaensis Zheng

- In dorsal view anterior margin of vertex obtusely angled; humeral angles indistinct; prozonal carinae long, interhumeral carinae long.............................................................................................3

3. Apex of hind process obtusely rounded; external lateral carina of pronotum folded upwards above tegmen indistinctly, not extending backwards. Distributed in India (Darjiling)......................................... Y. elytratus (Günther)

- Apex of hind process triangularly concave; external lateral carina of pronotum folded upwards above tegmen distinctly, extending backwards and reaching 3/4 of hind femur. Distributed in Thailand (Chiang Rai)...................................................................................................... Y. variabilis Zha & Wen sp. nov.

4. Vertex 2.8(♂) or 2.7 (♀) times as wide as one eye; antennae inserted between lower margins of eyes; lateral ocelli situated middle of inner margins of eyes; external lateral carina of pronotum not reaching apex of hind process; female upper valva stout, margin of sub-base smooth, middle widest. Distributed in Thailand (Nakhon Ratchasima, Loei, Chiang Mai)....................................................................................... Y. thaicus Storozhenko & Pushkar

- Vertex 3.17(♂) or 3.6 (♀) times as wide as one eye; antennae inserted slightly below lower margins of eyes; lateral ocelli situated lower 1/3 of inner margins of eyes; external lateral carina of pronotum reaching apex of hind process; female upper valva relatively slender, sub-base widest with serrate margin. Distributed in Thailand (Nan)..... .. Y. nanensis Zha & Wen sp. nov.