Four new species of the genus Metachelifer Redikorzev, 1938 are described from caves in the provinces of Tak (M.takensis sp. nov. and M.thailandicus sp. nov.), Chiangmai (M.mahnerti sp. nov.), and Nakhon Ratchasima (M.cheni sp. nov.). An identification key is provided to all known world representatives of the genus Metachelifer.
Keywords: Identification key; Southeast Asia; pseudoscorpion; taxonomy; troglobiont.
Yun-Chun Li, Ai-Min Shi.