Diolcogaster laetimedia Zeng & Chen

Zeng, Jie, He, Jun-hua & Chen, Xue-xin, 2011, The genus Diolcogaster Ashmead, 1900 (Hymenoptera, Braconidae, Microgastrinae) from China, ZooKeys 129, pp. 49-87 : 66-70

Diolcogaster laetimedia Zeng & Chen sp. n. Figs 33-40

Description.

Female. Body length 2.9 mm, fore wing length 3.3 mm.

Head. Rather large, subtriangular in anterior view, with antennal sockets high above middle level of eyes; oval in dorsal view, 1.5 × as wide as long and a little longer than mesoscutum, strongly concave behind ocular area, scattered with very short setae except the sharply constricted and highly polished area behind lateral ocelli. Ocelli small, in a low triangle, but the transverse, posterior tangent to the anterior ocellus a little before the posterior pair. POL:OD:OOL=5.3:3.4:4.7. Vertex shiny, convex, ocular area polished, with distantly discrete fine punctures out of ocular area; frons polished and without setae in large part but densely rugulose and setose adjacent to eye margin; face slightly convex, also shiny, densely but shallowly punctate, longitudinal median keel only indicated on dorsal 1/4, width of face 0.7 × as high as eye and clypeus combined (19.0:26.8); eyes rather large, inner margin of eyes parallel, 1.6 × as high as wide (28.0:17.8); temple and gena shiny, densely but feebly transversely striate-punctate, with dense appressed setae. Clypeus densely rugulose, slightly convex; tentorial pits of moderate size, distance between tentorial pits 2.4 × as long as distance from pit to eye margin; malar space very short, only 0.2 × as long as eye height. Antennae long and thin, with the preapical segment fully 2.5 × longer than wide; flagellomeres not thickened apically, without bristly setosity, with placodes arranged regularly in 2 ranks; apical segment distinctly longer than preapical one. Flagellomere proportion: 2 L/W=5.0, 8 L/W=2.4, 14 L/W=1.8; L 2/14=2.1; W 2/14=0.4.

Mesosoma. Pronotum shiny, with a shallowly striate ventral furrow laterally, densely and discretely punctate above. Mesoscutum shiny, with very dense and evenly discrete punctures, with dense short setae all over; notauli not impressed. Disc of scutellum also shiny, covex, as densely punctate as mesoscutum; its rugose tip at middle widely interrupting the posterior, polished band of scutellum. Lateral part of the polished band distinctly convex anteriorly. Anterior margin of the postscutellum closely applied to the posterior margin of the scutellum so that, laterally, the phragma of scutellum is completely hidden. Scutellar sulcus deep but narrow, with few strong longitudinal carinae, its width as long as scutellum (16.0:16.0). Propodeum with surface coarsely rugose on anterior 2/3 and polished on posterior 1/3, with strong costulae around spiracles and dull inside, with a very strong complete median keel. Mesopleuron polished above precoxal sulcus but with dense setigerous-punctures anteriorly and below precoxal sulcus; precoxal sulcus indicated by a shallow depression, with few punctures.

Wings. Forewing with the areolet is 4-sided, vein r(1st abscissa of the radius) much longer than vein 3-SR (2nd abscissa of the radius), arising from distal 1/2 of pterostigma, far behind the middle, very obliquely placed on the pterostigma, meeting vein 2-SR at 110 degree angle. Vein 1-R1 (metacarp) with distal end sharply defined, 4.8 × as long as its distance from the apex of the marginal cell and 1.2 × as long as pterostigma; pterostigma 3.0 × as long as wide; r:2-SR:length of pterostigma=10.5:7.0:31.0. Width of 1st discal cell:height of 1st discal cell =27.0:19.0; 1-CU1:2-CU1:m-cu=8.2:16.0:10.5. Hind wing with vannal lobe evenly convex, fringed with long setae throughout.

Legs. Long and strong. Hind coxa large, reaching to posterior margin of T3, shiny, with dense and evenly discrete punctures, evenly setose all over. Hind tibia swollen apically, 0.8 × as long as hind tarsus (58.0:76.0), outer surface with very sparse fine spines. Inner hind tibial spur longer than outer one, 0.5 × as long as hind basitarsus (18.0:34.5); fourth tarsal segment shorter than fifth tarsal segment (6.9:10.0); apical segment of the front tarsus without a spine. Tarsal claws simple.

Metasoma. Shorter than mesosoma. T1 slightly narrowed toward apex, shiny, finely rugulose and with distinct median groove on anterior 3/5, densely rugose and with appressed setae on posterior 2/5, 2.0 × as long as its width and twice as long as T2. T2 transverse, narrowed apically, anterior corner distinctly projecting anteriorly, longitudinally aciculate with interspaces rugose and without setae, without trace of median field, with very sparse short fine setae, 0.7 × as long as wide and as long as T3. T3 subrectangular, very finely longitudinally aciculate, also with very few fine setae. Tergites posterior to T3 membranous, polished, sparsely setose. Ovipositor sheath slightly widened apically, straight, without modified setae at apex. Hypopygium large, evenly sclerotised, polished with sparse long fine setae, apex not surpassing the last tergite.

Colour. Body black, somewhat brownish; metasoma dark brown, lighter and more or less transparent ventrally. Antennae brown except for 3-4 white middle flagellomeres with scape and pedicel transparent ventrally. Mouthparts brownish yellow, ventral margin and apex of labium brown, palpi whitish yellow. Tegula brown. Legs almost brown, with fore and middle legs lighter, except the trochanters, fore and middle coxae and ventral part of hind coxa pale yellow; hind femur yellow at base; tibial spurs whitish yellow. Wings hyaline; veins and pterostigma brown, except the basal pale spot of pterostigma.

Variation. Some individuals from Hainan Island with legs and metasoma lighter coloured, indicated by yellow colour.

Male.

Unknown.

Host.

Unknown.

Material examined.

Holotype: ♀, Mt. Nanling (112°59'E, 24°53'N ~ 113°05'E, 24°56'N), Ruyuan, Guangdong, 2004. V. 8, legs. Xu Zaifu, No. 20049497. Paratype: 1♀, Mt. Nanling (112°59'E, 24°53'N ~ 113°05'E, 24°56'N), Ruyuan, Guangdong, 2004. V. 8, legs. Xu Zaifu, No. 20049461; 2♀♀, Mt. Chebaling (114°14'E, 24°43'N ~ 114°16'E, 24°44'N), Shixing,Guangdong, 2002. IV. 19, legs. Xu Zaifu, No. 20050439, 20050825; 2♀♀, Mt. Chebaling (114°14'E, 24°43'N ~ 114°16'E, 24°44'N), Shixing, Guangdong, 2003. VIII. 21, legs. Xu Zaifu, No. 20051996, 20052381; 1♀, Mt. Gutian (118°07'E, 29°14'N ~ 118°10'E, 29°16'N), Kaihua, Zhejiang, 2005. VII. 2, legs. Wu Qiong, No. 200616858; 1♀, Mt. Gutian (118°07'E, 29°14'N ~ 118°10'E, 29°16'N), Kaihua, Zhejiang, 2005. VII. 3, legs. Wu Qiong, No. 200616985; 1♀, Mt. Gutian (118°07'E, 29°14'N ~ 118°10'E, 29°16'N), Kaihua, Zhejiang, 2005. VII. 3, legs. Chen Xuexin, No. 200616274; 1♀, Mt. Diaoluo (109°53'E, 18°39'N ~ 109°58'E, 18°42'N), Lingshui, Hainan, 2007. V. 28-VI. 1, legs. Zeng Jie, No. 200806652; 1♀, Tianchi, Mt. Jianfengling (108°48'E, 18°41'N ~ 108°49'E, 18°42'N), Ledong, Hainan, 2006. VII. 12-15, legs. Weng Liqiong, No. 200803277; 1♀, Tianchi, Mt. Jianfengling (108°48'E, 18°41'N ~ 108°49'E, 18°42'N), Ledong, Hainan, 2008. XI. 24, legs. Tan Jiangli, No. 200806060; 1♀, Letu (117°13'E, 24°53'N ~ 117°14'E, 24°54'N), Nanjing. Fujian, 1991. V. 23, legs. Liu Changming, No. 20006002.

Etymology.

The specific name “laetimedia” derives from the Latin adjective “laetus” and noun “media”, referring to middle of antennae with bright white color.

Distribution.

China (Zhejiang, Fujian, Guangdong, Hainan).

Remarks.

This species is similar to Diolcogaster connexus (Nees, 1834), but can be distinguished by the pterostigma emitting radius much distal to middle (the latter with pterostigma emitting radius at most slightly beyond middle); T2 as long as T3 (the latter with T2 much shorter than T3); and tergites posterior to T3 only sparsely setose (the latter with metasoma with dense setae, especially on T3).