Zethus dolosus Bingham, 1897

Lien Thi Phuong Nguyen & James M. Carpenter, 2016, Taxonomic review of the genus Zethus Fabricius (Hymenoptera: Vespidae: Eumeninae) from Vietnam with descriptions of four new species, Entomological Science 2016, pp. 1-9 : 2-3

Zethus dolosus Bingham, 1897 ( Figs 1–6 )

Zethus cyanopterus: Bingham, 1890: 244 ( Burma) .

Zethus dolosus Bingham, 1897: 332 (key), 333, female “ Burma (Pegu Hills); Tenasserim ” (The Natural History Museum, London).

Calligaster dolosa: Dalla Torre, 1904: 17 .

Material examined. Dien Bien: 1♂, La Xang, Muong Cha , 21°41 ’ 38"N, 103°04 ’ 40"E, 22.vii.2009, LTP Nguyen, PH Pham & J Kojima; 1♂, Muong Toong, Muong Nhe , 22°09 ’ 25"N, 102°34 ’ 19.5"E, LTP Nguyen, PH Pham & J Kojima; Lao Cai: 1♀, Nam Cuong , 19. viii.2006, LTP Nguyen, F Saito & J Kojima; Bac kan: 1♀, Na Lan , Lang Ngam , Ngan Son , about 260 m a.s.l., 21°48 ’ 15"N, 105°44 ’ 30"E, 17.x.2015, LTP Nguyen, DD Nguyen & MP Nguyen; Vinh Phuc: 1♀, Trai Trau , Me Linh , 22. viii. 2000, LTP Nguyen; Ha Noi: 1♀, Ba Vi NP, 700 m a.s.l., 14. viii. 2006, ISD; Bac Giang: 1♀, Thanh Son town, Son Dong , 120 m a.s.l., 5.vii.2010, PH Pham; Hoa Binh: 1♀, Lac village, Chieng Chau, Mai Chau , 600 m a.s.l., 10.vi.2008, LTP Nguyen & PH Pham; 1♀, Lac Thinh, Yen Thuy , 06.v.2002, TV Hoang; 1 ♀, Bao Hieu, Yen Thuy , 29.viii.2000, LTP Nguyen; Quang Nam: 1♀, Phuoc My , Phuoc Son , 670 m a.s.l., 28. vii.2004, ISD; Gia Lai: 1♂, Kon Ka Kinh NP , Konpne , Ka Bang , 850 m a.s.l., 14°23 ’ 23"N, 108°20 ’ 27.5"E, 16. vii.2012, LTP Nguyen.

The female of this species was described by Bingham (1897). Since then, no information on the male has been recorded. In this study, the female is redescribed and the male is newly described, with illustrations.

Redescription. Female. Body length 12.5 – 5.5 mm; forewing length 11.5 – 12.5 mm. Head in frontal view nearly circular, wider than high, 1.1× as wide as high ( Fig. 1 ). Vertex slightly produced behind eye. Frontal ocellus diameter half diameter of antennal socket. Distance from posterior ocelli to apical margin of vertex 2.2× as long as distance from posterior ocelli to inner eye margin. Area around ocelli swollen. Gena slightly narrower than eye, in lateral view 0.9× as wide as eye. Occipital carina complete, clearly present along entire length of gena. Inner eye margins strongly convergent ventrally; in frontal view distance of inner eye margins at vertex 1.1× than those at clypeus. A short medial carina is present between antennal sockets. Clypeus in lateral view gradually convex from base to near apical margin, then in a short distance straight to apical margin; in frontal view wider than high, 1.4× as wide as high ( Fig. 1 ), with basal margin emarginated, slightly concave medially and close to antennal sockets, apical margin emarginated medially, forming short and sharp tooth each lateral side, apical part between two teeth slightly convex, width of emargination 1/3× width of clypeus between inner eye margins ( Fig. 1 ). Mandible with four prominent teeth. Antennal scape 3× as long as its maximum width; FI 1.3× as long as its maximum width, FII – IX wider than long, FX bullet-shaped, as long as its basal width.

Mesosoma longer than wide in dorsal view, 1.4× as long as wide. Pronotal carina strongly raised, produced at humeral angles, reaching ventral corner of pronotum. Mesoscutum with notaulices developed (presenting from posterior margin to lateral margin of mesoscutum), in lateral view weakly convex, 1.1× as long as wide between tegulae; anterior margin broadly rounded. Scutellum flattened, slightly depressed in the middle, in lateral view at same level as mesoscutum, strongly depressed along anterior margin with 7 – 8 short longitudinal carinae. Metanotum slightly sloping down posteriorly. Propodeum with median part deeply concave, bordered by two lateral carinae, with a distinct median carina from near base to apex, with fovea at base ( Fig. 2 ), submarginal carina produced into pointed lamella.

Metasomal segment I petiolate, long and slender ( Fig. 3 ), T1 3.5× as long as wide, in dorsal view gradually widening from one-sixth of the tergum from base, then nearly parallel-sided apically ( Fig. 3 ), with maximum width 3× its basal width, with a medial carina which runs from basal margin to at least half the length, tergum and sternum fused, with a distinct suture between them throughout the segment and a longitudinal carina present medially, in lateral view abruptly swollen from near base, then gradually convex to apical margin, with dorsal margin nearly parallel to ventral margin ( Fig. 4 ). Metasomal segment II petiolate at base. TII in dorsal view gradually convex from base then nearly straight apically, longer than wide, 1.3× as long as wide, in lateral view angular at one-third distance from base ( Fig. 4 ). SII in lateral view ventrally tuberculate at two-fifths distance from base ( Fig. 4 ). TII & SII with well developed and raised apical lamella, TIII with thick apical lamella, not raised.

Body covered with rather long, silver hairs. Clypeus with dense, deep and large punctures, each bearing a long bristle, borders between punctures almost smooth, with some micropunctures. Mandible with small and deep punctures, each bearing a shorter and thicker bristle. Frons densely covered with deep, large and flat-bottomed punctures, border between punctures raised to form reticulation. Vertex and gena with dense, deep, and welldefined punctures, borders between punctures smooth. Pronotum with coarse and dense punctures medially, borders between punctures raised to form reticulation, lateral part along pronotal carina with transverse striae. Mesoscutum covered with shallow, small and sparse punctures, area between punctures almost smooth, usually larger than puncture, with several micropunctures. Punctures on scutellum similar to those on mesoscutum posteriorly. Punctures on metanotum larger and deeper than those on scutellum. Mesepisternum dorsally with dense, deep and large punctures, sparser ventrally, barely punctured anteroventrally. Metapleuron with strong and short striae in dorsal area, with some shallow punctures in ventral area. Propodeum with some oblique striae along each side of medial carina, with sparse and shallow punctures dorsally, with dense, large punctures at lateral part, borders between punctures strongly raised to form reticulation. TI covered with dense and coarse punctures; punctures on TII much finer and smaller, area between punctures smooth, about 2 – 3× larger than puncture diameter, punctures near base of TII denser and larger than those in other part of the tergum; TIII with dense and deep punctures; punctures on TIII – VI smaller and sparser, punctures on center of SII smaller and sparser than those on TII, punctures near lateral margin denser and larger than those on center.

Color. Black. Propodeal valvulae ferruginous. Wings dark brown, slightly infuscate, veins dark brown.

Male. Body length 13 – 15 mm; forewing length 10.5 – 11.5 mm.

The examined specimens of male agreed well with the female, but differing from the latter as follows: Head in frontal view transverse, much wider than high, 1.4× as wide as high ( Fig. 5 ). Eye strongly swollen laterally. Gena much narrower than eye, in lateral view 0.4× as wide as eye; in frontal view inner eye margins 1.2× further apart from each other at vertex than at clypeus. Clypeus in frontal view wider than high, 1.25× as wide as high, apical margin emarginated medially, forming short and blunt teeth laterally, apical margin between two teeth slightly concave. Mandible with four prominent teeth, the fourth tooth thick. FI 1.6× as long as its maximum width, FII – III longer than wide, FIV – VIII wider than long, FX small, FXI elongate, slightly curved, 3× as long as it basal width ( Fig. 6 ).

Color. Black. A reverse triangle at the center of clypeus, and a longitudinal stripe on mandible yellow.

Distribution. India (Meghalaya, West Bengal), China, Myanmar, Thailand, Vietnam.

Figures

Figures 1 – 7 Zethus dolosus (1 – 6). ♀ (1 – 4). 1 Head, frontal view. 2 Propodeum. 3 TI & II, dorsal view. 4 Metasomal segments I & II, lateral view. ♂ (5 – 6). 5 Head, frontal view. 6 Right antenna. 7 Z. malayanus, ♀, propodeum. Scale bar, 1 mm.