Stephanus tridentatus van Achterberg & Yang, 2004

Hong, Chun-dan, van Achterberg, Cornelis & Xu, Zai-fu, 2011, A revision of the Chinese Stephanidae (Hymenoptera, Stephanoidea), ZooKeys 110, pp. 1-108 : 43-45

Stephanus tridentatus van Achterberg & Yang, 2004 Figs 387396

Stephanus tridentatus van Achterberg and Yang 2004: 106-109.

Type material.

Holotype, ♀ (CAFB), "CHINA: Henan, Longyuwan, Luanchuan, 700 m, ovipositing on Cerambycidae larvae in Qishu tree, 10.vii.1996, Zhong-qi Yang". Paratypes (18 ♀ + 2 ♂: CAFB; 1 ♀: RMNH): 1 ♀, "CHINA: Henan Longyuwan, Luanchuan, ovipositing on Buprestidae larvae in Ulmus tree, 10.vii.1996, Zhong-qi Yang"; 5 ♀ + 2 ♂, "CHINA: Shaanxi, Louguantai, 9.ix.1991, ovipositing on Cerambycidae larvae in Quercus tree, Zhong-qi Yang"; 1 ♀ (RMNH), id.; 3 ♀, id., but 10.ix.1991; 3 ♀, id., but 11.ix.1991; 3 ♀, id., but 12.ix.1991; 1 ♀, id., but 13.ix.1991; 2 ♀, id., but 15.ix.1991.

Other material.

2 ♀ + 1 ♂ (ZJUH): 2 ♀, CHINA: Shaanxi, Mt. Xinjia, 28-30. vi.1992, No. 200011622; No. 200011617; 1 ♂, CHINA: Henan, Jiyuan, 7.vi.2000, Ping Cai, No. 200102040.

Diagnosis.

Pronotum (Fig. 388) with a coarse to fine pronotal fold medially; scutellum (Fig. 390) coarsely foveolate and somewhat smooth medially; large part of vein M+CU of hind wing pigmented (Fig. 387); hind femur (Fig. 394) with 3 large ventral teeth, rarely with 4 teeth ( van Achterberg and Yang 2004); first metasomal tergite (Figs 395, 396) often comparatively robust and 3-5.7 times as long as its maximum width.

Description.

Redescribed after a female from Shaanxi (Mt. Xinjia), length of body 13.8 mm, of fore wing 10.8 mm, and of ovipositor sheath 18.0 mm.

Head. Flagellum with 30 flagellomeres; first flagellomere moderately slender, 3.4 times as long as wide, and 0.8 times as long as second flagellomere; frons (Fig. 393) coarsely reticulate-rugose; three anterior lobe-shaped coronal teeth of head large; both posterior ones connected and ear-like, behind them with two distinct lobes laterally and four curved, progressively smaller carinae; medio-dorsally remainder of vertex rather finely transversely striate, laterally and including area behind posterior ocelli reticulate, sculpture becoming finer posteriorly and narrowly reaching occipital carina (Fig. 391); temples smooth except for some punctures ventrally, shiny and moderately angulate in dorsal view (Fig. 392).

Mesosoma. Neck (Figs 388, 389) comparatively short and robust, anteriorly moderately concave, neck postero-dorsally at lower level than middle pronotum, with three pairs of distinct carinae laterally and smooth medially in front of pronotal fold, with distinct cavity under pronotal fold; pronotal fold distinctly developed and sinuate in dorsal view (Fig. 388); middle pronotum robust, with a very short median carina directly behind pronotal fold, with some irregular and rather coarse transverse carinae (Fig. 388); lateral oblique groove of pronotum distinct and rather wide, impression somewhat carinate and with wide smooth interspaces and ventral area below it coarsely rugose; postero-laterally narrowly short setose; posterior pronotum dorsally coarsely carinate-rugose; mesoscutum laterally densely coarsely rugose, medially foveolate and with rather distinct notauli and a median groove; scutellum (Fig. 390) coarsely foveolate; axillae with some spaced foveolae; propleuron coarsely punctate; convex part of mesopleuron reticulate-foveolate and covered with whitish and rather sparse setosity; dorsal part densely rugose and setose; mesosternum with coarse punctures; medially metapleuron strongly convex, coarsely foveolate-reticulate and with short whitish setosity, antero-ventrally weakly crenulate and with dorsal anterior depression and ventral depression rather deep; propodeum (Fig. 390) densely and irregularly rugose-foveolate.

Wings. Fore wing (Fig. 387): vein 1-M 3.3 times as long as vein 1-SR and weakly curved. Hind wing (Fig. 387): vein M+CU largely pigmented.

Legs. Hind coxa rather robust, subelliptical, anteriorly coarsely rugose, posteriorly striate; hind femur (Fig. 394) slender, largely finely transversely striate, with three acute, large teeth and some denticles in between, laterally sparsely setose; basal narrow part of hind tibia about 1.1 times as long as widened part, parallel-sided and with ventral carina; outer side of widened part of hind tibia coriaceous and with sparse small punctures bearing whitish setae (Fig. 394); inner side flattened, sparsely granulate, apically with densely bristly setose area; hind basitarsus parallel-sided, basally hardly curved, ventral length 6.0 times its width.

Metasoma. First tergite (Figs 395, 396) rather robust, subcylindrical, 5.7 times as long as its maximum width, largely irregularly and coarsely transversely rugose, basally much coarser and slightly reticulate; second tergite basally rugose, remainder smooth; pygidial area distinctly differentiated, narrowly lamelliform posteriorly, pygidial impression deep and reverse Y-shaped; length of ovipositor sheath 1.3 times as long as body.

Colour. Blackish or dark brown; face brownish; malar space yellowish, distinctly contrasting to temple and vertex; fore wing membrane largely pale brownish; tibiae, tarsi brownish, and hind trochantellus pale brown; ovipositor sheath completely blackish.

Male. Very similar to female, but smaller: length of body 11.5 mm and of fore wing 7.7 mm.

Variation. Female: length of body 13.8-16.9 mm, and of fore wing 10.1-12.8 mm; flagellum with 25-31 flagellomeres; middle teeth of hind femur maybe double, resulting in 4 ventral teeth in one leg and the normal 3 in the other leg ( van Achterberg and Yang 2004); first tergite 4.4-5.7 times as long as its maximum width; length of ovipositor sheath 1.6-1.8 times as long as fore wing and 1.2-1.3 times as long as length of body. Male: length of fore wing 7.7-8.7 mm; flagellum with 25-27 flagellomeres.

Biology.

A parasitoid of Buprestidae and Cerambycidae larvae in deciduous trees ( van Achterberg and Yang 2004).

Distribution.

Palaearctic China (Shaanxi, Henan).

Note.

The name refers to the three ventral teeth of the hind femur ( van Achterberg and Yang 2004).