Polistes gilvus Nguyen, Kojima, 2011

Lien, Nguyen Thi Phuong, 2020, Contribution to the taxonomy of the paper wasp genus Polistes (Polistella) (Hymenoptera: Vespidae: Polistinae) from Vietnam, with description of a new species, Zootaxa 4759 (2), pp. 252-260 : 257

Polistes gilvus Nguyen, Kojima and, 2011

Polistes gilvus Nguyen, Kojima and Saito, 2011 , Zootaxa 3060: 1, 17, figs. 54-60, 88, female, nest (in subgenus Polistella )— “ VIETNAM, Co Ma, Thuan Chau, Son La, 1600 m ” (IUNH).

Polistes gilvus was described by Nguyen, Kojima and Saito (2011) based on a female specimen (holotype) from Co Ma, Thuan Chau, Son La [ Vietnam], which is housed in the Natural History Collection at Ibaraki University, Mito, Japan (IUNH) on long-term loan from the Institute of Ecology and Biological Resources, and the nest of the species was also described at that time. This is an endemic species of Vietnam, the male of this species is described here for the first time and similar to the female both in structure and coloration except for some characters mentioned below.

Material examined. 1 male ( IEBR), Phan Can Su , Bat Xat NR, Lao Cai, 22°39′19″N 103°37′27″E, alt. 1931m, 1.viii.2019, Nguyen LTP, Nguyen CQ, Tran NT, Tran UTP .

Description. Male [female characters in square brackets]. Body length 8.6 mm [8.5–9.5 mm]; fore wing length 8.8 mm [9–10 mm].

Head in frontal view ( Fig. 11 ) about 1.5 × [about 1.2 ×] as wide as high. Frons flat. Vertex slightly raised in area among ocelli; POD:OOD=1:1.9 [1:2.2]; POD about 1. 7× [about 1.4 ×] Od. Eye much more strongly swollen laterally than in female; inner eye margins about 1.6 × [about 1.1 ×] further apart from each other at vertex than at clypeus. Gena narrow [more or less wide], in lateral view about 0.6 × [about 0.8 ×] as wide as eye. Clypeus in frontal view ( Fig. 11 ) 1.2 × as wide as high [as wide as high], apical margin slightly produced, broadly rounded [pointed apically]; in lateral view slightly convex dorsally, slightly concave ventrally [weakly convex]; surface covered with dense short golden setae [upper half of clypeus covered with fine pale pubescence and lower half with scattered deep large punctures each bearing sharply pointed golden bristle]. Antenna ( Fig. 12 ) with slenderer flagellomere than in female; scape long, about 3.5 × [more than 3.0 ×] as long as its maximum width; F1 3.2 × [slightly more than 2.5 ×] as long as apical width; F2 longer than wide [as long as wide]; F9-10 somewhat flatten at inner lateral margin; terminal flagellomere slightly curved [bullet shaped], about 2.6 × longer than [as long as] its basal width.

Mesosoma as in female. Pronotal carina sharply raised, produced into thin lamella in dorsal part, slightly sinuate on lateral sides, and reaching ventral corner of pronotum. Mesoscutum weakly convex, slightly longer than wide between tegulae. Disc of scutellum convex. Metanotum weakly convex, strongly depressed along anterior margin. Propodeum short; posterior face widely (about half the maximum width of propodeum) and shallowly excavated medially, more or less smoothly passing into lateral faces; propodeal orifice elongate, about 2 × as long as wide (measured at widest part), somewhat narrowed in dorsal half. Jugal lobe of hind wing large, rounded.

Metasoma except two terminal segments as in female. T1 distinctly shorter than its apical width, in lateral view abruptly swollen dorsally just behind basal slit for reception of propodeal suspensory ligament; corner between anterior and dorsal faces bluntly angled. S 2 in lateral view with dorsal margin slightly longer than its ventral margin; anteroventral corner in nearly right angle. S7 depressed medially, with tubercle.

Body surface sculpture as in female, except for unpunctured clypeus. Mandible with scattered shallow punctures. Frons and vertex up to level of posterior ocelli with close fine punctures. Vertex behind posterior ocelli and gena with sparse fine punctures, spaces between punctures smooth. Pronotum with dense deep punctures; spaces between punctures very narrow, strongly raised to form reticulation. Mesoscutum with dense and deep flat-bottomed punctures. Scutellum and metanotum with dense deep flat-bottomed punctures, but punctures smaller than those in mesoscutum. Mesepisternum with coarse dense well- defined punctures in posterodorsal part; punctures in dorsal margin similar to those on pronotum. Dorsal metapleuron with week striation; ventral metapleuron with shallow large punctures. Propodeum with distinct transverse striation and punctures between striae on lateral faces; interpuncture spaces weakly raised to interconnect striae. Metasomal segements densely covered with minute punctures in addition to scattered small punctures (ill-defined on terga; more or less well-defined on sterna).

Color. Almost similar to female [body black, with following orange-yellow markings: clypeus except black margins, line on gena along posterodorsal margin of eye, narrow band along pronotal carina with branches running along posterior margin of pronotum, two spots on metanotum, apical bands on T1 and 5 (wide). Legs black. Wings pale brown, weakly infuscate, slightly more strongly infuscate along anterior margin of forewing; veins dark brown], but clypeus entirely yellow, narrow orange-yellow band along pronotal carina without branches running along posterior margin of pronotum, and with two orange-yellow spots on scutellum.

Male genitalia. Similar to those of other Polistella species. Digitus in inner aspect of paramere ( Fig. 13 ) about 3.5 × as long as wide (measured at widest part), distinctly swollen near base, gradually narrowed apically to round apex. Aedeagus ( Figs. 14–15 ): penis valve slightly longer than basal apodeme, in ventral view swollen laterally in proximal one fourth and distinctly produced laterally near proximal margin, in lateral view slightly thickened in proximal one fourth and with dorsal margin weakly and smoothly sinuate, with proxomoventral corner produced into nearly right angle ( Fig. 14 ); ventral serration of penis valves coarse and strong, especially in proximal half of penis valves ( Fig. 15 ).

Figures

FIGURES 11–20. Characters of Polistes species from Vietnam. 11–15. Polistes gilvus, male. 11. Head, frontal view. 12. Left antenna. Genitalia. 13. Inner aspect of paramere with digitus and volsella. 14, 15. Aedeagus. (14. Ventral and 15. Lateral view). 16–20. Polistes brunus, male. 16. Head, frontal view. 17. Left antenna. Genitalia. 18. Inner aspect of paramere with digitus and volsella. 19, 20. Aedeagus. (19. Ventral and 20. Lateral view). Scale 1mm.