A new Plagiotrochus Mayr oak gall wasp species from Taiwan (Hymenoptera: Cynipidae: Cynipini)

A new species of oak gall wasp, Plagiotrochus tarokoensis Tang and Melika sp. nov., is described from Taiwan. The species induces integral leaf galls on Quercus tarokoensis (Fagaceae). Data on the diagnosis, distribution, and biology of the new species are given. This is the second known Plagiotrochus species from the Oriental region and the first one known to associate with the Ilex group of section Cerris oaks within Quercus linnaeus subgenus Quercus.