Abstract
A new linyphiid genus Callosagen. n., with two new species Callosa ciliatasp. n. (♂♀, type species) and Callosa baiseensissp. n. (♂♀), from southwest China are described. Detailed description of genitalic characters and somatic features is provided, as well as light microscopy and SEM micrographs of each species. Callosagen. n. was found in caves in Yunnan and Guangxi, and its copulatory organs are similar to those of Bathyphantes and Porrhomma, but differ greatly in details. The monophyly and placement of Callosagen. n. are supported by the results of molecular analysis.