Polistes (Polistella) khasianus Cameron , 1900

Nguyen, Lien T. P. & Carpenter, James M., 2016, Review of the Polistes (Polistella) " Stenopolistes " species-group (Hymenoptera: Vespidae: Polistinae) from Vietnam, with description of a new species and key to species, Zootaxa 4088 (4), pp. 583-593 : 586-588

Polistes (Polistella) khasianus Cameron, 1900

( Figs 7–13 )

Polistes khasianus Cameron, 1900: 413 , ♀ —[ India: Meghalaya] “Khasia Hills” [holotype in Oxford University Museum, Oxford].

Polistes khasianus was recorded from middle and northwestern parts of Vietnam (Nguyen & Kojima 2013; Nguyen & Pham 2011), but careful examination of the description of P. khasianus by Das & Gupta (1989) and comparison with the description of P. pallidus by Gusenleitner (2011) showed that it is not P. khasianus but P. pallidus , a species close to P. khasianus with the metasomal tergum 1 sharply angled basally and fore wing without a subapical fuscous cloud. In this study, two specimens of P. khasianus were collected in the northeastern part of Vietnam together with nests as detailed below. The species has the clypeus dark brown (Das & Gupta 1989) but the specimens from Vietnam have the clypeus yellow. The color pattern of Vietnamese specimens otherwise fits with that described by Das and Gupta (1989).

Material examined. VIETNAM: Lao Cai: Hoang Lien NP, Sa Pa, 1 ♂, 1830 m, 28.ix.2013, TV Tran; 1 ♀, Tram Ton, 2200 m, Nest#VN-HL-2015-P-01, 14.v.2015, TV Hoang; 1 ♀, Tram Ton, 2200 m, Nest#VN-HL-2015- P-02, 16.v.2015, TV Hoang.

Male genitalia. Generally similar to that of P. clandestinus (Nguyen et al., 2011) . Digitus in inner aspect of paramere ( Fig. 10 ) 3 × as long as wide (measured at widest part), distinctly swollen near base, gradually narrowed apically to mid-length, then slightly swollen towards the rounded apex. Aedeagus ( Figs 11, 12 ), penial valves 1.3 × longer than basal apodeme, in ventral view narrowest near mid-length, nearly straight from mid-length then strongly swollen and distinctly produced laterally near proximal margins, in lateral view slightly thickened in proximal one fourth and with dorsal margin strongly sinuate, with proximoventral corner produced into acute angle ( Fig. 12 ); ventral margins of penial valves finely serrated along entire length.

Nest. The nest of Polistes khasianus is described here for the first time.

The two early stage nests, Nest#VN-HL-2015-P-01 ( Fig. 13 ) and Nest#VN-HL-2015-P-02 were collected together with only 1 ♀ on each nest. The two nests were attached to two long and not very broad leaves, at 2 m above the ground. Nest Nest#VN-HL-2015-P-01 has 31 cells, with 25 eggs and was without pupa; and nest Nest#VN-HL-2015-P-02 has 42 cells, with 33 eggs, 2 larvae and was without pupa. The structural and morphological characters are as follows: comb tough, pliable “paper”-like in texture, more or less uniformly gray in the cell walls, subcircular (19 mm x 18 mm for Nest Nest#VN-HL-2015-P-01 and 23 mm x 19 mm for Nest#VN-HL-2015-P-02) in view from the side of the cell opening, expanded concentrically from the single petiole, with surface corresponding to the cell bottom slightly concave. The nests have petiole single, terminal, attached to the border between bottoms of the first three cells, 4.8 mm long and 0.9 x 1.0 mm thick at the midlength in the nest Nest#VN-HL-2015-P-01, and 4.4 mm long and 0.8 x 0.9 mm thick at the mid-length in the nest Nest#VN-HL-2015-P-02, with thin central core of plant fibers, enlarged strictly with adult oral secretion, dark brown and lustrous, secretion coat expanded on comb back around the petiole and on substrate in 2 mm x 3 mm thin film. Cells are generally arranged in regular rows, pentagonal at open end; for the nest Nest#VN-HL-2015-P- 0 1 each cell expanded towards open end, the largest cell was 5.0 mm, the other cells were 3.8 mm (range 3.5–4.5 mm; n=10) wide at open end, 2.3 mm (range 1.7–2.6 mm; n=10) wide at bottom and 13.8 mm in largest cells, cell wall 0.06 mm thick; for the nest Nest#VN-HL-2015-P-02 each cell expanded towards open end 3.7 mm (range 3.4– 4.3 mm; n=10) wide at open end, 2.6 mm (range 2.5–3.0 mm; n=10) wide at bottom, cell wall 0.07 mm thick.

Distribution. This species was recorded from northern India (Haryana, Meghalaya, West Bengal) and northeastern Vietnam (this study). Like P. delhiensis and P. nigritarsis , the species has a disjunct distribution, probably due to lack of intensive field work.

Figures

FIGURES 7 – 13. Polistes khasianus. 7. Head, frontal view. 8. Habitus. 9. Head, frontal view. 10 – 12. Genitalia. Scale 1 mm. 10. Inner aspect of paramere with digitus and volsella. 11, 12. Aedeagus (11. Ventral and 12. Lateral view). 13. Nest. 7, 8. ♀. 9 – 12. ♂.