Key to species of the genus Stephanus Jurine

(Modified from van Achterberg, 2002)

1. Temples smooth and shiny, at most with few punctures; hind femur shiny, largely smooth, superficially coriaceous or finely striate; outer side of hind tibia of female with fine striae ventrally and ventrally with carina; base of pterostigma with indistinct pale brownish spot; femora blackish or dark brown dorso-apically; head dark orange- or reddish-brown and with yellowish spot between base of mandible and eye, hardly contrasting with temple or blackish and with distinct ivory spot; hind tibia of female blackish or brown [East Palaearctic, Oriental ( Sunda area)].................................................... 2

- Temples coriaceous, with several coarse punctures and rather matt; hind femur matt, distinctly finely granulate; outer side of hind tibia of female without striae ventrally and ventrally without carina, only more or less angulate; base of pterostigma with distinct white spot; femora narrowly white-tipped dorso-apically (female, more conspicuously so in male); head largely blackish or dark brown and with ivory spot between base of mandible and eye, distinctly contrasting with temple; hind tibia of female yellowish-brown (of male more or less dark brown) [West Palaearctic].......................... S. serrator (Fabricius)

2. First metasomal tergite about 9× as long as its apical width (female; male: 13.5×) (Fig. 104); hind femur with 2 large ventral teeth (Fig. 103); pronotum with deep cavity and no distinct pronotal fold medially; small part of vein M+CU of hind wing pigmented (Fig. 102); scutellum densely rugose [East Palaearctic (China); Oriental (India (present report))]........................................................................................... S. bidentatus van Achterberg

- First tergite 3–5× as long as its apical width; hind femur with 3 large ventral teeth, rarely with 4 teeth; pronotum with indistinct to medium sized cavity and with a coarse to fine pronotal fold medially; large part of vein M+CU of hind wing pigmented; scutellum largely smooth................................................................................ 3

3. Head blackish and with a distinct ivory spot, contrasting with temple; temples rather angulate in dorsal view; pronotum without a distinct cavity below pronotal fold; medially vertex regularly and rather finely transversely striate; hind femur partly finely (rugose-)striate [East Palaearctic (China)]........................................... S. tridentatus van Achterberg

- Head dark orange or reddish brown and with yellowish spot between base of mandible and eye, hardly contrasting with temple; temples roundly narrowed in dorsal view; pronotum with a cavity below pronotal fold; medially vertex irregularly and densely rugose; hind femur mainly smooth, at most superficially coriaceous [Oriental ( Sunda area)].......................... 4

4. Hind basitarsus dark brown, and not contrasting with hind tibia; at least basal half of outer side of hind coxa finely irregularly rugose; hind leg more robust; pronotum and first metasomal tergite rather coarsely sculptured [Oriental (Borneo, Java)]................................................................................... S. borneensis (de Saussure)

- Hind basitarsus rather pale brown, and contrasting with dark hind tibia; outer side of hind coxa largely smooth; hind leg slender; pronotum and first tergite finely sculptured [Oriental (West Malaysia)]......................... S. soror van Achterberg