Rogadini Foerster, 1862

Oanh, Nguyen Thi, Dzuong, Nguyen Van, Long, Khuat Dang, Lam, Pham Van, Nhi, Pham Thi & Hoa, Dang Thi, 2021, Six new braconid wasps of the genus Colastomion Baker, 1917 (Hymenoptera: Braconidae: Rogadinae) from Vietnam, Zootaxa 5040 (2), pp. 215-237 : 217

Tribe Rogadini Foerster, 1862

Genus Colastomion Baker, 1917: 283 .

Type-species: Colastomion abdominalis Baker, 1917 (by monotypy).

Diagnostic characters. Colastomion Baker differs from Macrostomion Szépligeti by having first metasomal tergite nearly linearly widened basally; hypopygium of female strongly or distinctly convex ventrally; third maxillary palp segments of male extremely inflated. A detailed diagnosis of the genus Colastomion was given by van Achterberg (1991) and Chen & He (1997).

Comments. Colastomion is most likely closely related to Macrostomion Szépligeti, 1900 , however, van Achterberg (1991) and Chen & He (1997) note they have not seen species with distinct variation on fore vein cu-a and hind wing vein 2-SC+R, although the new species from Vietnam, Colastomion asperum , sp. nov., has vein 2-SC+R nearly longitudinal. Additionally, three of nine Colastomion species described by Quicke et al. (2012) from Papua New Guinea are also remarkable in that they have fore wing vein cu-a antefurcal, a feature that in other rogadines might be taken to be of generic importance.