Pararrhynchium concavum Nguyen, sp. nov. (Figs 9–14) Material examined. HOLOTYPE, ♀ [IEBR], “ VIETNAM, Phia Oac NR, Nguyen Binh, Cao Bang, 22°35'N, 105°51'E, 1035m, 7-10.v.2013, Tru V. Hoang”. Diagnosis. This species can be distinguished from all congeners by the following combination of features: Gena as wide as eye; propodeum with horizontal area shorter than length of metanotum, posterior surface bordered by pronounced curved carina; T1 with partial transverse carina at base which visible at lateral sides. Description. Female. Body length 10 mm; fore wing length 9.0 mm. Structure as in Pararrhynchium striatum sp. nov., but differs as follows: Head in frontal view slightly wider than high (Fig. 9). Distance from posterior ocelli to apical margin of the vertex 1.5 × distance from posterior ocelli to inner eye margin (Fig. 11). Gena as wide as eye. Inner eye margins in frontal view 1.2 × further apart from each other at vertex than at clypeus. Apical margin of clypeus with width of emargination slightly more than 1/3 width of clypeus between inner eye margins (Fig. 10); in lateral view prominently convex at basal half, then running straight to apical margin. Propodeum with horizontal area shorter than length of metanotum, posterior surface dull, slightly concave, bordered by pronounced curve carina with V-shaped incision in the middle above, upper part of propodeum forming pair of relatively blunt teeth behind metanotum (Fig. 12), median carina indistinct at upper two-third, at short distance from apical of valvula the carina produce to form blunt teeth. Body covered with slightly coarser punctures than in P. striatum sp. nov. Clypeus covered with deep punctures, each bearing golden bristle, diameter of punctures larger than distance between punctures, punctures coarser on apical half. Propodeum with deep coarse punctures in dorsally, border between punctures cariniform; punctures smaller laterally; posterior surface dull, with shallow large punctures. Color. Black except spots on base of mandible and antennal scape beneath orange-yellow. Wings dark brown, strongly infuscate, veins dark brown. Male. Unknown. Distribution. Northern Vietnam: Cao Bang. Etymology. The specific name refers to the curve in the propodeal carina (concavo in Latin). Remarks. This species is similar to P. striatum, but can be easily distinguished from the latter by having the gena as wide as the eye (gena narrower than eye in P. striatum); the punctures on frontal face of pronotum less dense and smaller, propodeal carina that separates its posterior and lateral faces curved; posterior face of propodeum dull (shiny in P. striatum); punctures on T3–4 deeper and larger than in P. striatum.

Published as part of Nguyen, Lien Thi Phuong, 2015, Two new species of the genus Pararrhynchium de Saussure (Hymenoptera: Vespidae: Eumeninae) from northern Vietnam, pp. 170-176 in Zootaxa 3974 (2) on pages 174-175, DOI: 10.11646/zootaxa.3974.2.2, http://zenodo.org/record/237353