Twenty species of Libnotes ( Laosa) Edwards, 1926 are known worldwide and three are known from China so far. Here, two species of Laosa are added to the Chinese fauna, of which L. ( L.) baiyunensis sp. nov. is described and illustrated as new to science, and L. ( L.) fuscinervis Brunetti, 1912 is newly recorded from China. Morphologically, the new species is most similar to L. ( L.) charmosyne (Alexander, 1958) but can be distinguished by the pleura of the thorax, the relative position of the additional cross veins in cell r 3 and r 5, and the details of the male genitalia. A key to the world species of Laosa is presented.