Abstract
BACKGROUND: The subfamily Opiinae comprises more than 2,000 valid species worldwide. Members of this subfamily are koinobiont endoparasitoids, with parasitism generally culminating in the eventual death of the host. Several species of Opiinae have been utilised for biological control of agricultural pests. The genus Opius is the largest genus within Opiinae, with more than 1,000 valid species worldwide. It is divided into several subgenera, classification of which remains under active discussion. The genus Apodesmia was formerly regarded as a subgenus of Opius, but was elevated to genus level, based on differences in the form of the occipital carina. NEW INFORMATION: Opius youi Li & van Achterberg, 2013 is recorded for the first time from South Korea, representing the first record of the species outside China. Apodesmia incisula Fischer, 1963 is also newly recorded from South Korea, constituting the first record of the species outside Europe, where it was previously known from Germany and the Netherlands. For each species, detailed morphological descriptions are provided, accompanied by diagnostic characters illustrated with photographs of the relevant body structures. The barcode region of mitochondrial cytochrome c oxidase I (COI) was also analysed for the species.