Discoelius nigerrimus Nguyen

Nguyen, Lien Thi Phuong, 2016, A new record of the genus Discoelius Latreille, 1809 (Hymenoptera: Vespidae: Eumeninae) from Northern Vietnam with description of two new species, Zootaxa 4154 (5), pp. 589-594 : 593

Discoelius nigerrimus Nguyen , sp. nov.

( Figs 6–8 )

Diagnosis. Clypeus emarginated at basal margin, with median carina from half of clypeus to supraclypeal area, apical margin nearly truncated; first metasomal segment petiolate, short and thick, T1 with swollen part in dorsal view nearly 1.6 × as long as wide, abruptly widening at one-fourth of the tergum from base, then slightly narrowly to apical margin; T2–T3 with well developed apical lamella, and T4 with apical lamella at only lateral corners.

Material examined. HOLOTYPE, ♀, “ VIETNAM, Ta Chai, Bac Ha, Lao Cai, 26.vi.2008, LTP Nguyen [ IEBR].

Description. Female. Holotype. Body length 13 mm; fore wing length 12.3 mm. Structure as in Discoelius aurantiacus sp. nov., but differs as follows. Inner eye margins in frontal view as far apart from each other at vertex as at clypeus. Clypeus in frontal view slightly greater than 1.3 × as wide as long ( Fig. 6 ), emarginated at basal margin, with median carina from half of clypeus to supraclypeal area. T 2 in dorsal view longer than wide, 1.2 × as long as wide ( Fig. 7 ). T2–T3 with developed apical lamella ( Fig. 8 ), and T4 with apical lamella at only lateral corners.

Color. Black, with two faint orange marks near anterior margin of pronotum. Propodeal valvulae dark brown. Wings dark brown, strongly infuscate, veins dark brown.

Male. Unknown.

Distribution. Northern Vietnam: Lao Cai.

Etymology. The specific name refers to the black in the body.

Remarks. This species is similar to Discoelius aurantiacus sp. nov., but can be easily distinguished from the latter by having clypeus emarginated at basal margin (nearly straight in D. aurantiacus ), T 2 in dorsal view proportionally longer, about 1.2 × as long as wide (1.1 × as long as wide in D. aurantiacus ), and T4 with apical lamella at lateral corners (T4 without apical lamella in D. aurantiacus ). This species can be distinguished from other species of the genus by the combination of the following characters: T1 with swollen part in dorsal view nearly 1.6 × as long as wide, T2 & 3 with developed apical lamella, T4 with apical lamella at lateral corners, and color pattern.

Figures

FIGURES 6 – 8. Discoelius nigerrimus sp. nov., holotype, ♀. 6. Head, frontal view. 7. Propodeum and metasoma, dorsal view. 8. Metasoma, lateral view.