Megischus ptosimae Chao, 1964

Hong, Chun-dan, van Achterberg, Cornelis & Xu, Zai-fu, 2011, A revision of the Chinese Stephanidae (Hymenoptera, Stephanoidea), ZooKeys 110, pp. 1-108 : 29-32

Megischus ptosimae Chao, 1964 Figs 240251

Megischus ptosimae Chao 1964: 378-379, 387-388, Figs I (1), II (3-4), IV (14), V (6, 10); van Achterberg and Yang 2004: 112-115; Hong et al. 2010: 61.

Material.

6 ♀+ 1 ♂: 2 ♀ (SCAU), CHINA: Guangdong, Chebaling, 26.vii.2008, Zai-fu Xu, No. 200800183; Chun-dan Hong, No. 200800184; 1 ♀ (ZJUH), CHINA: Sichuan, Nanchong, 24.vi.1940, No. 65021.10; 1 ♀ (ZJUH), CHINA: Zhejiang, Quxian, 24.v.1959, Zheng-nan Zhou, No. 5931.1; 1 ♂ (ZJUH), CHINA: Zhejiang, Hangzhou, 7. vii. 1980, Ben-yue Zhang, No. 810242. 1 ♀ (CAFB): "China: Shaanxi, Yangling, 30.viii.1994, ovipositing on larvae of Buprestidae on Prunus sp., Zhong-qi Yang", "det C. van Achterberg, 2004". 1 ♀ (RMNH): "China: Fujian, Fuzhou, Westlake, 8.v.1963, Zhen-cai Zhang, RMNH 03", "det C. van Achterberg, 2003".

Diagnosis.

Head largely blackish or dark brown; temple medially slightly convex behind eye in dorsal view (Fig. 244); neck at lower level than middle pronotum postero-dorsally (Fig. 242); pronotal fold distinct and with a cavity below it (Figs 241, 242); vein 1-M of fore wing 4.2-5.5 times as long as vein 1-SR and 1.1-1.3 times vein m-cu; vein cu-a of fore wing weakly reclivous or subvertical (Fig. 240); widened part of hind tibia of female distinctly concave ventrally (Figs 248, 249), but straight in male (Fig. 251); hind basitarsus 3.0-3.5 times as long as wide; first tergite largely transversely striate or striate-rugose; whitish or ivory part of ovipositor sheath 0.7-2.0 times as long as dark apical part (Fig. 250).

Description.

Redescribed after a female from Guangdong (Chebaling), length of body 13.9 mm, of fore wing 7.5 mm, and of ovipositor sheath 12.8 mm.

Head. Flagellum with 32 flagellomeres; first flagellomere slender, 4.0 times its maximum width, and 0.9 times as second flagellomere; frons (Fig. 246) coarsely reticulate-rugose and covered with few scattered short setae; coronal area somewhat reticulate and with some short carinae, three anterior coronal teeth large, both posterior ones small and as sinuate transverse and wide lamellae; vertex (Fig. 244) with three coarse carinae, two anterior ones strong and arcuate, the last one much shorter, followed by broadly reticulate-rugose and sparsely pubescent area, sculpture postero-dorsally gradually weaker near occipital carina; temple (Fig. 245) smooth and shiny, except for small punctures with associated setae on ventral half of temple and narrowly along eye orbit, temple slightly bulging behind eye in dorsal view.

Mesosoma. Neck (Figs 241, 242) moderately slender, anteriorly moderately emarginate, medio-dorsally largely smooth, laterally with three pairs of strong, oblique carinae, anterior two pairs narrowly interrupted dorsally, the posterior pair curved backwards and apically widely separated; neck postero-dorsally at much lower level than middle pronotum, resulting in a distinct, deep cavity below pronotal fold; pronotal fold stout and strongly developed; middle pronotum dorsally at about same level with posterior pronotum and strongly striate-rugose; posterior pronotum largely foveolate and with smooth interspaces, foveolae with associated long setae and some foveolae dorsally coalescent; lateral ventral groove narrowly impressed and smooth, area below it obliquely rugose; propleuron coriaceous and setose; prosternum densely foveolate, foveolae circular and setose; mesoscutum largely densely and strongly foveolate, some foveolae coalescent, generating areolation; notauli and median groove distinct, formed by closely aligned foveolae; axillae foveolate, foveolae deep and separated by about their diameter, axillae separated basally by a large fovea; scutellum (Fig. 243) irregularly distributed with circular foveolae and with smooth interspaces, foveolae laterally denser than dorsally; mesopleuron largely coarsely and densely punctate-rugose, each foveola bearing long and thin seta; convex part of metapleuron densely foveolate and with long whitish setosity, antero-ventrally crenulate and with both anterior and ventral depressions rather deep; propodeum (Fig. 243) dorsally almost glabrous, completely with shallow, circular foveolae, most foveolae separated by about 0.1 of their diameter, some of them coalescent.

Wings. Fore wing (Fig. 240): wing subhyaline, and surface evenly bristly; vein M+CU1 with four short, erect, equidistant setae; basally vein 1-1A with about 10 erect, approximately equidistant setae grouped at base; vein 1-M 4.8 times as long as vein 1-SR and 1.1 times vein m-cu; vein 2-SR 1.4 times vein r; vein r ends 0.4 length of pterostigma behind level of apex of pterostigma; vein 1-SR 0.5 times as long as parastigmal vein; vein cu-a postfurcal and subvertical; vein 3-CU1 entirely nebulous and curved apically; first subdiscal cell slightly open posteriorly.

Legs. Hind coxa rather robust, subelliptical, with long whitish setosity strongly inclined towards apex, coarsely spaced punctate-rugose, but posteriorly transversely striate; hind femur (Fig. 247) with scattered punctures and largely smooth and shiny interspaces, each puncture bearing one long whitish seta, hind femur ventrally with two large teeth and several minute teeth in between and behind apical one; hind tibia (Figs 248, 249) 1.4 times longer than hind femur, largely sparsely punctate and with long setae, basal narrow part of hind tibia 0.3 times as wide as widest part; outer side of widened part basally widely and rather steeply depressed and ventrally strongly concave, apical part rather robust; inner side of widened part basally slightly depressed and smooth, followed by coarsely granulate area, apically densely setose; hind tarsus bristly setose ventrally, hind basitarsus robust and somewhat widened apically.

Metasoma. First tergite transversely striate-rugose, 6.2 times as long as its maximum width, 1.7 times as second tergite and 0.6 times as remainder of metasoma; basal 0.2 of second tergite weakly rugose, remainder largely coriaceous and somewhat microareolate; remainder of tergites transversely densely and finely aciculate and sparsely short setose, setae on last two tergites denser; pygidial area with moderately long setae, laterally distinctly impressed and centrally convex, medially granulate; pygidial impression somewhat reversed U-shaped; length of ovipositor sheath 0.9 times as long as body length, length of subapical whitish band nearly 1.6 times length of dark apical part.

Colour. Largely black or dark brown; most of head, mesosoma and hind coxa black or blackish; malar space and basitarsi ivory; temple and basal 0.3 of hind tibia orange or reddish brown; wing membrane light brownish; antenna, veins, pterostigma, legs (except basal 0.3 of hind tibia and basitarsus), and most of metasoma brown or dark brown; mandible except its apex black; clypeus, fore and middle legs, lateral part of metasoma (except first tergite) yellowish brown; ovipositor sheath largely black and with whitish subapical band.

Male. Very similar to female, but smaller, length of body 12.7 mm, and of fore wing 6.3 mm; widened part of hind tibia ventrally not concave but more or less straight (Fig. 251); hind tarsus with five tarsomeres.

Variation. Female: length of body 9-20.7 mm, of fore wing 6.8-12.5 mm, and of ovipositor sheath 9-21.0 mm; flagellum with 28-36 flagellomeres; vein 1-M 4.2-5.5 times as long as vein 1-SR and 1.1-1.3 times vein m-cu; first tergite 6.1-8.4 times as long as its maximum width, 1.7-2.4 times second tergite and 0.6-0.8 times remainder of metasoma; length of ovipositor sheath 0.9-1.0 times as long as body length, length of subapical whitish or ivory band 0.7-2.0 times length of dark apex. Male: length of body 6.5-17 mm.

Biology.

A parasitoid of Ptosima chinensis Mars. ( Buprestidae ) larvae in peachtrees, and of Buprestidae in other Prunus species ( Chao 1964).

Distribution.

China (Shaanxi, Zhejiang, Sichuan, Fujian, Guangdong).

Note.

The name of this species is derived from the generic name of its host, Ptosima chinensis ( Chao 1964).