Taxonomic review of the genus Zethus Fabricius (Hymenoptera: Vespidae: Eumeninae) from Vietnam with descriptions of four new species Author Lien Thi Phuong Nguyen Author James M. Carpenter text Entomological Science 2016 2016 1 9 journal article 10.1111/ens.12218 03a6dd3f-a52a-4d60-bc0d-944c00931276 269807 Zethus tansoneus Nguyen & Carpenter , sp. nov ( Figs 24–28 ) Holotype , ♂ , “ VIETNAM , Tan Son , Mai Chau , Hoa Binh , 1000 m , 14 .vi. 2008 , LTP Nguyen ” [ IEBR ]. Paratype : VIETNAM : Quang Nam : 1 ♂ , Phuoc My , Phuoc Son , 450 m a.s.l., 2 .v. 2005 , Insect Systematic Department ’ s collectors [ IEBR ]. Description Male. Holotype . Body length 11.5 mm ; forewing length 10 mm . Structure similar to Z. tumidus sp. nov. but differs as follows: frontal ocelli smaller with diameter 0.7 × as wide as antennal socket diameter ( Fig. 24 ). Gena with a longitudinal medial carina running from base to near half the length of the gena. FI proportionally shorter, 1.7 × as long as its maximum width, FII longer than wide, FII as long as wide, FIV – IX wider than long, FXI elongate, thinner, proportionally longer, 2.8 × as long as it basal width ( Fig. 25 ). Mesoscutum and scutellum in lateral view less convex than in Z. tumidus , almost at same level. Metanotum not projected over propodeum. Medial concave area of propodeum without oblique striae, with some short transverse striae near base ( Fig. 26 ). Metasoma in dorsal ( Fig. 27 ) and lateral view ( Fig. 28 ) as in Z. tumidus . Figures 19–23 Zethus tumidus sp. nov. , holotype ♂. 19 Head, frontal view. 20 Right antenna. 21 Propodeum, dorsal view; 22 TI & II, dorsal view. 23 Metasomal segments I & II, lateral view. Scale bar, 1 mm. Figures 24–28 Zethus tansoneus sp. nov. , holotype ♂. 24 Head, frontal view. 25 Right antenna. 26 Propodeum, dorsal view. 27 TI & II in dorsal view. 28 Metasomal segments I & II, lateral view. Scale bar, 1 mm. Figures 29–32 Zethus propodeus sp. nov. , holotype ♀. 29 Head, frontal view. 30 Propodeum, dorsal view. 31 TI & II, dorsal view. 32 Metasomal segments I & II, lateral view. Scale bar, 1 mm. Distribution . Vietnam : Hoa Binh. Etymology. The specific name refers to the type locality, Tan Son in Mai Chau, Hoa Binh province of Vietnam .