Eumenes gibbosus Nguyen, sp. nov.

Eumenes gibbosus Nguyen, sp. nov.

(Figs 1–6, 15)

Material examined. HOLOTYPE, ♀, “ VIETNAM, Pa Co, Mai Chau, Hoa Binh, 1000 m, 23.VIII.2005, L.T.P. Nguyen & J. Kojima [IEBR]. PARATYPES: VIETNAM: [IEBR] 1 ♀, same data as holotype; Ha Giang: 1 ♀, Ma Le, Dong Van, 23°17'9"N 105°18'2"E, 29.XI.2014, LTP Nguyen, LX Truong, MP Nguyen & DD Nguyen; Yen Bai: 1 ♂, Van Chan, 21°36'10"N 107°30'32"E, DD Nguyen; [VNMN] Son La: 2 ♀, Co Ma, Thuan Chau, 2.VI.2009 & 4.VI.2009, PH Pham.

Description. Female. Body length 10.5–11 mm (holotype: 10.5 mm); fore wing length 8.6–9.6 mm (holotype: 8.6 mm). Head in frontal view subcircular, 1.3 × as wide as high (Fig. 1). Distance from posterior ocelli to apical margin of vertex 0.9 × distance from posterior ocelli to inner eye margin. Gena much narrower than eye, in lateral view 0.4 × as wide as eye. Occipital carina complete, present clearly along entire length of gena. Inner eye margins strongly convergent ventrally; in frontal view 1.6 × as further apart from each other at vertex as clypeus. Clypeus in lateral view strongly convex at basal two-third, then straight to apical margin; in frontal view higher than wide, 1.1 × as high as wide (Fig. 1), with basal margin slightly convex medially and distinctly separated from antennal sockets; apical margin deeply emarginate medially, forming round tooth on each lateral side (Fig. 1); width of emargination about equal to 1/3 width of clypeus between inner eye margins. Mandible with prominent teeth, fourth tooth long and pointed apically. Antennal scape 3 × as long as its maximum width; F1 2 × as long as wide, F2–4 slightly longer than wide, F5–9 wider than long, F10 bullet-shaped, its length about equal to its basal width.

Mesosoma longer than width in dorsal view. Pronotal carina slightly raised, reaching ventral corner of pronotum. Mesoscutum convex, slightly shorter than wide between tegulae; anterior margin broadly rounded. Disc of scutellum slightly convex. Metanotum angle, crenulated at edge before sloping down to apical margin. Propodeal groove distinct from base to apex, without fovea.

T1 2.3 × as long as wide, in dorsal view abruptly widen from one-third near base, then parallel to near apical margin, and slightly constrict near apical margin (Fig. 3). T 2 in lateral view gibbous, constricted near apical margin, with base strongly swollen dorsally, base of T2 forms with sternum obtuse angle (Fig. 2), in dorso-posterial view pear shape, 1.2 × as long as wide, with transverse sulcus at middle near apical margin (Fig. 4); S 2 in lateral view slightly convex.

Body covered with short, pale yellow setae except temple and mesosoma with longer setae. Clypeus with deep and sparse punctures at center, punctures at sides smaller, space between punctures usually larger than puncture diameter. Mandible with several shallow small punctures. Frons densely covered with deep large punctures, space between punctures raised to form reticulation. Vertex and gena with deep and well-defined punctures, interspaces between punctures smooth. Pronotum with coarse punctures, spaces between punctures narrow, strongly raised to form reticulation. Mesocutum densely and coarsely covered with flat-bottomed punctures, puncture near lateral margin with interspaces raised to form reticulation. Punctures on scutellum similar to those near lateral margin of mesoscutum, with some smooth areas in middle. Punctures on metanotum very coarse and dense. Mesepisternum with big and coarse punctures posterodorsally as in pronotum, barely punctured anteroventrally; border between posterodorsal and anteroventral parts indistinct. Metapleuron with week short striae at lateral of dorsal area, with sparse shallow punctures in ventral area. Propodeum with punctures on dorsal surface similar to those on pronotum, punctures on lateral parts smaller and shallower than in dorsal part. T1 covered with large and deep punctures, with interspace larger than puncture diameter at lateral parts, punctures on T2 smaller and denser than those on T1, sparser at lateral parts; punctures on T3–5 much smaller and weaker than those on T1–2; T6 with minute punctures; punctures on S2 small, shallow and sparse.

Color. Black. An orange-yellow spot between antennae. The following parts orange: short line at vertex behind eye, band at basal margin of pronotum with irregular shape, transverse line on metanotum (anterior and posterior margin black), apical band on T1, T2 and S2 (band on T1 on apical, swollen and shiny, rim, anteriorly emarginated medially and laterally), spot on lateral side of T2 (absent in one female). Lateral margin of tegula, propodeal valvulae, outer side at base of fore and mid- tibia, spot on fore and mid- femora at apex, dark brown. Wings dark brown, slightly infuscate, veins dark brown.

Male. Body length 10 mm; fore wing length 8.0 mm. Structure as in female, but differing as follows: Head in frontal view 1.2 × as wide as high (Fig.5). Distance from posterior ocelli to apical margin of the vertex slightly greater than the distance from posterior ocelli to inner eye margin. Inner eye margins in frontal view 2 × further apart from each other at vertex than at clypeus. Clypeus in frontal view 1.5 × as wide as high, apical margin deeply emarginate medially, forming sharp triagle tooth on each lateral side (Fig. x), width of emargination nearly 1/2 width of clypeus between inner eye margins (Fig. 5). Mandibular with four distinct teeth on inner side, basal tooth long and point apically. Antennal scape 3 × as long as its maximum width; F1 2.5 × as long as its maximum width, F2–5 longer than wide, F6–9 wider than long, F10 small, as long as wide, F11 slightly curve, slightly less than 2.5 × as long as its basal width (Fig. 6).

Color. As in female, and F11 dark brown.

Distribution. Vietnam: Ha Giang, Son La, Hoa Binh.

Remarks. This species can be distinguished from E. nigriscutatus Zhau, Chen & Li, 2012, from China, E. tosawae Giordani Soika, 1941, and other Eumenes species by the combination of the following characters: metasomal segment 1 2.3 × as long as wide, metasomal segment 2 gibbous with the base of T2 forming with the sternum an obtuse angle but dorsal part not strongly swollen and the transverse sulcus not so deep as in E. nigriscutatus and E. tosawae, and the color pattern.

Etymology. The specific name refers to the distinct gibbosity of T2.