A new species of the genus Systasis Walker, 1834 (Hymenoptera: Pteromalidae) parasitizing an important invasive alien insect pest Obolodiplosis robiniae (Diptera: Cecidomyiidae) from China.

A new species of genus Systasis Walker (Hymenoptera: Pteromalidae), Systasis obolodiplosis Yao et Yang, sp. nov., was found in China and was described in this paper. The new species is a parasitoid of larvae-pupae of locust gall midge Obolodiplosis robiniae (Haldemann) (Diptera: Cecidomyiidae) which is a newly invaded serious insect pest in China. Systasis obolodiplosis can be regarded as a potential natural enemy agent for biological control of this pest. Morphological characters are depicted in details and partially illustrated here. Type specimens are deposited in Insect Museum Collection of Chinese Academy of Forestry.