Delta de Saussure 1855

Genus Delta de Saussure, 1855

Delta de Saussure 1855: 130, 132, 143, name for divisions II and III of genus Eumenes Latreille in de Saussure 1852: 44, 60. Type species: Vespa maxillosa De Geer, 1775 [Vespa emarginata Linnaeus, 1758], by subsequent designation (Bequaert 1925a: 137), erroneously as Sphex maxillosus De Geer, corrected by Bequaert 1926: 487. Senior subjective synonym of Phi de Saussure, 1855 (type species: Vespa arcuata Fabricius, 1775) and of Erinys Zirngiebl, 1953 (type species: Vespa unguiculata Villers, 1789 by monotypy). Raised to generic rank by Blüthgen 1953: 3.

Delta: Carpenter 1986: 68; van der Vecht & Carpenter 1990: 18; Nguyen 2015b: 95 –96.

Diagnosis. Mandibles elongate, longer than length of clypeus, teeth absent or inconspicuous. Clypeus little longer than wide, shallowly emarginate or widely truncate apically. Cephalic foveae absent. Vertex narrow and sloping behind lateral ocelli. Anterior face of pronotum smooth and shiny without medial pits or foveae. Thorax globular in shape, longer than wide (Fig. 13). Pronotal carina usually incomplete, not developed on lateral sides of pronotum. Notauli absent. Pretegular carina present (Fig. 18). Epicnemial carina absent on mesepisternum. Tegula longer than wide, generally rounded or weakly emarginate adjoining parategula, posterior end not reaching end of parategula (Fig. 25). Scutellum generally convex. Metanotum not dentate. Axillary fossa wide (Fig. 25). Propodeal dorsum below plane of metanotum, sloping posteroventrally. Superior carina absent. Propodeal orifice wide dorsally. Submarginal carina not produced as pointed/rounded process above valvula. Propodeal vuvlula not separated from submarginal carina posteriorly. Metasoma petiolate, petiole length less than 1.25 × length of mesosoma, never shorter than mesosoma (Figs 64, 76) (this character distinguish Delta from closely related Phimenes and Oreumenoides). T1 usually smooth and wider in apical half. S1 rather gradually widening towards apex, lateral margins of T1 not meeting ventrally usually visible along entire petiole length (Fig. 69). Apical margin of T2 not lamellate (Fig. 73). S2 usually concave medially. Mid tibia with one apical spur. SMC2 basally acute. Prestigma equals or little longer than pterostigma. Ƌ: F11 hooked, pointed apically, longer than previous ones; F8 with a cavity on its inner margin (Fig. 12). Body length usually more than 20 mm.

Distribution. Southern Palearctic, Oriental, Australian, Ethiopian Regions and New World (introduced).