Orancistrocerus, van der Vecht, 1963

Truong, Lam Xuan, Bozdoğan, Hakan & Nguyen, Lien Thi Phuong, 2019, Taxonomic studies on the genus Orancistrocerus van der Vecht, 1963 (Hymenoptera: Vespidae: Eumeninae) from Vietnam, with description of a new species, Zootaxa 4563 (3), pp. 595-599 : 599

Key to species of genus Orancistrocerus

The characters are applicable to both sexes unless the sex is specified. The characters of O. moelleri and O. bicoloripennis are taken from the descriptions of the species, following van der Vecht (1963), Yamane (1990), and the key to species by van der Vecht (1963), except for specimens of O. aterrimus nigreceps from Vietnam and O. drewseni drewseni from China.

1 Metasomal tergum II sparsely punctate, interspaces much greater (two to three times) than puncture diameter, except at base and at apical margin with interspaces smaller than puncture diameter. Orange-yellow markings present as follows: large interantennal spot on clypeus, spot near base of mandibles, antennal scape beneath, apical bands of terga I-II............................................................................................. O. drewseni (de Saussure, 1857)

- Metasomal tergum II densely punctate, interspaces larger (about 1.5 times) than puncture diameter, except at base and at apical margin with interspaces equal or smaller than puncture diameter. Mesosoma with yellow apical band on terga I-II or extensively marked with red or entirely black.................................................................... 2

2 Female clypeus with apical margin deeply emarginated, half-oval shaped, with an inverse U-shaped mark near basal margin of clypeus and apical bands of terga I-II yellow................................................... O. altus , sp. nov.

- Female clypeus with apical margin shallowly emarginated..................................................... 3

3 Wings yellowish or light cupreous brown, not conspicuously infuscated on apical half. Mesosoma extensively marked with red.............................................. O. moelleri ( Bingham, 1897)

- Wings subhyaline or yellow, strongly infuscated at apex....................................................... 4

4 Mandible with ivory white spot at base. Basal part of wings rich golden hyaline, apical half fuscous with golden and violaceous reflections............................................................ O. aterrimus (de Saussure, 1852)

- Mandibles with irregular yellow spot at base. Wings with less pronounced yellow tinge; the apical cloud covers the marginal cell, the second and third submarginal cells and the areas below and beyond these cells... O. bicoloripennis (Gribodo, 1892) .