Key to the Caliscelini of Vietnam (modified after Gnezdilov et al. 2014)

1. Coryphe elongate, with lateral margins converging at acute angle (Figs 2, 5, 6). Metope with well developed median and sublateral carinae; median one running throughout postclypeus (Figs 3, 21)................ Cylindratus fansipan sp. nov.

–. Coryphe nearly as wide between the eyes as long medially or transverse. Metope with another pattern of carination....... 2

2. Fore femora and tibiae foliately flattened.................................................................. 3

–. Fore femora and tibiae not flattened...................................................................... 4

3. Fore femora and tibiae flattened into an oval (Figs 24, 25).............. Caliscelis (Cerepa) carnavalis Emeljanov, 2015

–. Fore femora and tibiae flattened into almost a circle (Figs 26, 27).......... Caliscelis (Cerepa) gnezdilovi Emeljanov, 2015

4. Coryphe and metope joint at acute angle (in lateral view) (Fig. 29). Metope 1.5 times as long at midline as wide between the eyes, with median carina. Coryphe with angularly convex anterior margin. First and second metatarsomeres each with one latero-apical spine................................................... Gelastissus hokutonis (Matsumura, 1916)

–. Coryphe and metope joint at obtuse angle (in lateral view) (Fig. 28). Metope 1.2 times as wide between the eyes as long at midline, without median carina. Coryphe transverse, with widely truncate anterior margin. First and second metatarsomeres each with two latero-apical spines............................. Annamatissus tami Gnezdilov et Soulier-Perkins, 2014