Two new species of the millipede genus Gervais, 1847 (Diplopoda, Spirostreptida, Cambalopsidae) from caves in northern Thailand.

Two new species of the genus Gervais, 1847 are described and illustrated. The first species, , is the second species of the -group to be found in Thailand. It resembles Jiang, Guo, Chen & Xie, 2018, from southern China, but is distinguished by a smaller size and the carinotaxic formula of the collum, combined with ♂ legs 1 bearing very strongly reduced telopodites, the anterior gonopods showing a pair of very long and slender apicomesal processes, and the denser plumose and stout flagella of the posterior gonopods. The second species, , the fifth member of the -group in Thailand, seems to be particularly similar to Likhitrakarn, Golovatch & Panha, 2017, from Laos. However, it can be distinguished from the latter species mainly by showing a uniformly yellow collum and the posterior gonopod coxite bearing several strong setae in median and lateral views, coupled with the anterior gonopod coxosternum being microsetose in the anterior and medial parts in caudal view. An identification key to, and a distribution map of, all seven species currently known to occur in Thailand are also provided.