Taxonomic notes on the solitary wasp genus Symmorphus Wesmael, 1836 (Hymenoptera, Vespidae, Eumeninae) from Vietnam

Based on specimens deposited in the Institute of Biology, Vietnam Academy of Science and Technology (IB; Hanoi, Vietnam), we provide taxonomic notes on the solitary wasp genus Symmorphus Wesmael, 1836 (Hymenoptera, Vespidae, Eumeninae) from Vietnam. The subgenus Parasymmorphus Cumming & van der Vecht, 1986 is recorded from Vietnam for the first time, represented by Symmorphus (Parasymmorphus) parvilineatus (Cameron, 1904), which is also a new country record.

Two additional species, S. (Symmorphus) lamriensis Gusenleitner, 2010 and S. (Symmorphus) sichuanensis Lee, 1981, are newly recorded from Vietnam. The female of S. laoticus Gusenleitner, 2010 is described for the first time based on Vietnamese material. Distributional data and photographs are provided for the treated taxa.

In addition, the male genitalia of three species are described and illustrated in detail for the first time, improving species recognition and facilitating future identification work on the Vietnamese Symmorphus fauna.