A gall midge pollinating flowers of Kadsura longipedunculata is described as Resseliella kadsurae sp. nov. based on adult specimens collected in 2006 from Langshan, Xinning County, Hunan Province, China. The new species is distinguishable from other known congeners in the combination of the following characteristics: gynecoid male flagellomeres, mottled wings, simple claws on all legs; male hypoproct with a transverse bridge-like structure ventrally connecting both sides of hypoproct. In particular, the gynecoid male flagellomeres and transverse bridge-like structure are unique to the new species. Partial sequencing of the cytochrome oxidase subunit I mitochondrial gene indicates that R. kadsurae is grouped with the R. theobardi + R. yagoi clade, but this clade and the monophyly of the genus Resseliella are not statistically supported. The new species is nocturnal, and mating occurs at dusk. At the time of mating, males and females hang on opposite sides of non-sticky old spider webs in a venter-to-venter position. Immature stages and the life history of R. kadsurae are unknown. The flower-visiting habit of R. kadsurae is contrasted with that of other flower-visiting gall midges and the probability that this behavior exists in other congeners is discussed.