Larvae of the genus Silba Macquart, 1875 were obtained from the syconia of three different species of Ficus growing on the southern islands of Japan and Taiwan. Examination of the emerged adults identified four species, two of which are described as new to science: Silba erecta MacGowan and Arimoto sp. nov. and Silba thunbergii MacGowan and Arimoto sp. nov. Of the four species observed, the larvae of S. erecta, Silba ishigaki MacGowan and Okamoto, 2013 and S. thunbergii feed on the tissue of the fig syconia. Silba inubiwa MacGowan and Okamoto, 2013 was observed as a predator of three fig wasp species. The biogeographic distribution and biological data are provided for each of these fig-associated species