Diolcogaster brevivena 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 : 57-60

Diolcogaster brevivena Zeng & Chen sp. n. Figs 9-16

Description.

Female. Body length 2.7mm, fore wing length 2.8mm.

Head. Small, subquadrate in anterior view, with antennal sockets high above middle level of eyes; strongly transverse in dorsal view, 1.6 × as wide as long and almost as long as mesoscutum, with very short fine 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 not cutting the posterior pair. POL:OD:OOL=4.0:3.0:7.0. Vertex vey shiny, flattened; frons polished, virtually with out sculpture; face convex, also very shiny, with sparse fine punctures, feebly transverse striate on upper half, without any trace of median keel, width of face 0.8 × as high as eye and clypeus combined (16.6:20.0); eyes small, inner margin of eyes parallel, 1.6 × as high as wide (18.0:11.0); temple and gena shiny, densely and finely striate, with appressed longer setae. Clypeus separated from face by a fine curved line linking the tentorial pits, slightly convex and as finely and sparsely punctate as face; tentorial pits small, distance between tentorial pits 2.7 × as long as distance from pit to eye margin; malar space short, 0.3 × as long as eye height. Antennae much shorter than body, with the preapical segment only 1.2 × as long as wide; flagellomeres slightly thickened apically, with bristly setosity, with placodes arranged regularly in 2 ranks; apical segment longer than preapical one. Flagellomere proportion: 2 L/W=3.0, 8 L/W=1.5, 14 L/W=1.4; L 2/14=1.8; W 2/14=0.6.

Mesosoma. Pronotum shiny, with a broad ventral furrow laterally. Mesoscutum very shiny, very densely but finely punctate, with posterior margin distinctly rimmed, with dense short fine setae all over; notauli not impressed, only slightly depressed on the posterior imaginary course. Disc of scutellum polished, shiny and at most weakly punctate, with sparse fine setae; polished at tip, so the posterior, polished band of scutellum is continuous. 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 shallow, with few indistinct longitudinal carinae, its width as long as scutellum (13.0:13.0). Propodeum short, shiny, with a strong complete median keel, smooth with very sparse fine punctures, except for very short transverse carina each side along the median keel and dense rugulosity around spiracles. Mesopleuron polished, area behind anterior margin setigerous-punctate; precoxal sulcus only indicated medially by a very shallow depression.

Wings. Forewing with areolet more or less 4-sided, vein r-m reduced to a transparent point and received onto vein r+3-SR, vein r much longer than vein 3-SR, arising from distal 1/2 of pterostigma, far behind the middle, placed at almost right angles to the pterostigma; meeting vein 2-SR at a 160 degree angle. Vein 1-R1 (metacarp) with distal end sharply defined, 1.9 × as long as its distance from the apex of the marginal cell and 0.8 × as long as pterostigma; pterostigma short and broad, 2.8 × as long as wide; r:2-SR:length of pterostigma=8.0:7.0:28.0. Width of 1st discal cell: height of 1st discal cell = 20.5:17.5; 1-CU1:2-CU1:m-cu = 7.0:11.0:6.0. Hind wing with vannal lobe evenly covex, fringed with long setae throughout.

Legs. Long and thin. Hind coxa with dense fine punctures with interspaces smooth and shiny, with dense short fine setae medially and on posterior 1/3; dorsal surface also with dense fine punctures and dense short fine setae. Hind tibia swollen apically and only 0.7 × as long as hind tarsus (38.0:49.7), outer surface without spines. Inner hind tibial spur longer than outer one, 0.6 × as long as hind basitarsus (13.0:21.9); fourth tarsal segment much shorter than fifth tarsal segment (5.0:7.0); apical segment of the front tarsus without a spine. Tarsal claws simple.

Metasoma. Longer than mesosoma. T1 parallel-sided but roundly constricted distally, surface shiny with anterior 3/4 smooth and posterior 1/4 shallowly rugulose, with sparse fine setae dorsally and laterally; 1.1 × as long as its width and 1.5 × as long as T2; the percurrent median groove reduced on apex. T2 trapezoid, polished, with a slightly convex median field separated from other parts by two lateral sulci sharply narrowed on anterior half and parallel on posterior half, 0.5 × as long as wide and 0.8 × as long as T3. Tergites posterior to T2 more membranous, highly polished with a row of short fine setae before posterior margin, except the last two segments scattered with short fine setae. Ovipositor sheath slightly widened apically, decurved, with 2-3 blackened setae at apex. Hypopygium large, evenly sclerotised, polished, with very few long fine setae, apex not surpassing the last tergite.

Colour. Body black, metasoma brownish. Antennae yellowish brown at base and darkened toward apex to brown, pedicel brown. Mouthparts brownish yellow with palpi lighter. Tegula also brownish yellow. Legs almost virtually brownish yellow, except basal 4/5 of hind coxa, apex of hind femur and tibia and apex of claws brown. Tergites of abdomen evenly dark brown, basal sternites transparent and yellowish. Wings hyaline; veins brown, pterostigma, 1-R1(metacarp), submaginal vein and r vein darker.

Variation. Paratype with the same characteristics as holotype, but slightly different in colour pattern.

Male.

Unknown.

Host.

Unknown.

Material examined.

Holotype: ♀, Natural Park of Mt. Gaoligong (98°46'E, 24°49'N), Lujiangba, Baoshan, Yunnan, 2009. V. 10-11, legs. Wang Manman, No. 200903858. Paratype: 1♀, Natural Park of Mt. Gaoligong (98°46'E, 24°49'N), Lujiangba, Baoshan, Yunnan, 2009. V. 10-11, legs. Wang Manman, No. 200903862.

Etymology.

The specific name “brevivena” derives from the Latin prefixion “brevi-” and noun “vena”, referring to the distinctly short metacarp.

Distribution.

China (Yunnan).

Remarks.

This species is similar to Diolcogaster minuta (Reinhard, 1880), but can be distinguished by T2 highly polished (the latter with T2 strongly rugose) and vein 1-R1 much longer than its distance from the apex of the radial cell (the latter with 1-R1 vein at most a little longer than its distance from the apex of the radial cell).