Diolcogaster punctatiscutum 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 : 76-79

Diolcogaster punctatiscutum Zeng & Chen sp. n. Figs 65-72

Description.

Female Body length 2.8 mm, fore wing length 3.2 mm.

Head. Oval in anterior view, with antennal sockets high above middle level of eyes; transverse in dorsal view, 1.6 × as wide as long and almost as long as mesoscutum, with dense short fine setae except the sharply constricted and highly polished area behind lateral ocelli. Ocelli of moderate size, in a low, very wide triangle, the transverse, posterior tangent to the anterior ocellus just cutting the posterior pair. POL:OD:OOL=5.8:4.2:7.5. Vertex vey shiny, with very sparsely discrete punctures, strongly convex; frons polished, virtually without sculpture; face slightly convex, also very shiny, finely but densely punctate, with denser setae, without any trace of median keel, width of face 1.1 × as high as eye and clypeus combined (26.8:24.1); eyes small, inner margin of eyes slightly widened downwards, 1.6 × as high as wide (22.0:14.0); temple and gena shiny with denser and deeper punctures than vertex, and with longer setae. Clypeus indistinct, slightly convex and as finely and densely punctate as face; tentorial pits large, distance between tentorial pits 3.0 × as long as distance from pit to eye margin; malar space short, 0.2 × as long as eye height. Antennae longer than body, with the preapical segment fully twice as long as wide; scape short; flagellomeres thinner, tappered distally, without bristly setosity, with placodes arranged regularly in 2 ranks; apical segment longer than preapical one. Flagellomere proportion: 2 L/W=2.5, 8 L/W=3.1, 14 L/W=2.0; L 2/14=2.1; W 2/14=1.0.

Mesosoma. Pronotum shiny, with a very broad foveate ventral furrow laterally. Mesoscutum very shiny, evenly and densely punctate, with short fine setae all over; notauli not impressed. Disc of scutellum with denser punctures, larger laterally, with interspaces shiny, very densely setose; 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 deep and broad, with few longitudinal carinae, its width as long as scutellum (15.0:15.0). Propodeum short, shiny, reticulate-rugose all over, coarsely rugose laterally and with strong rugae around spiracles, with a strong complete median keel. Mesopleuron in large part polished (including area below precoxal sulcus posteriorly), the other part with setigerous-punctures. Precoxal sulcus only indicated on anterior half of mesopleuron, shallow and broad, feebly and largely foveate anteriorly and polished behind.

Wings. Forewing with areolet 4-sided; vein r (1st abscissa of the radius) much longer than 3-SR (2nd abscissa of the radius), arising from distal 1/2 of pterostigma, slightly behind the middle, placed at almost right angle to the pterostigma, meeting vein 2-SR at a 160 degree angle. Vein 1-R1 (metacarp) with distal end sharply defined, 3.9 × as long as its distance from the apex of the marginal cell and as long as pterostigma; pterostigma 3.1 × as long as wide; r:2-SR:length of pterostigma=12.5:5.0:32.5. Width of 1st discal cell:height of 1st discal cell =24.3:24.0; 1-CU1:2-CU1:m-cu=6.0:14.0:10.0. Hind wing with edge of vannal lobe beyond its widest part straight and without trace of a fringe of setae.

Legs. More or less stout. Hind coxa very shiny, with fine and very sparse punctures and dense short fine setae, inner surface with much shorter setae; rather small, not reaching to T3. Hind tibia swollen apically and 1.1 × as long as hind tarsus (49.0:46.3), outer surface with darkened but very indistinct spines. Inner hind tibial spur longer than outer one, 0.8 × as long as hind basitarsus (13.0:17.0); fourth tarsal segment much shorter than fifth tarsal segment (5.4:8.9); apical segment of the front tarsus without a spine. Tarsal claws simple.

Metasoma. Broad. T1 parallel-sided or slightly swollen medially, with anterior half surface smooth and shiny and sharply separated from coarsely and strongly reticulate-rugose posterior half surface by a strong carina on each side of median groove; the percurrent median groove indistinct on anterior half and sharply rimmed on posterior half, with few long setae in the middle laterally, 1.1 × as long as its width, and almost twice as long as T2; T2 transverse, shortened medially, with a raised pentagonal median field, shiny but densely rugulose all over; 2.8 × times as wide as long and 1.2 × as long as T3. T3 transverse with anterior margin curved, shiny with very fine rugulosity and a few short fine setae. Tergites posterior to T3 more membranous, highly polished with a row of short fine setae bordering anterior margins except for the last two segments which only have sparse short fine setae. Ovipositor sheath with even width, with a fine modified apical seta. Hypopygium large, evenly sclerotised, smooth and shiny, with long fine setae, apex slightly surpassing the last tergite.

Colour. Body dark brown to black, except metasoma yellow with brown apex. Antennae light brown at base and darkened toward apex to brown. Mouthparts lighter with mandible yellow and palpi white. Tegula whitish yellow. Legs almost virtually yellow, except apical 1/3 of hind tibia and apex of claws brown and hind basitarsus slightly brownish. Tergites almost yellow and somewhat transparent, except middle of T3 to T6 and hypopygium, T7, posterior half of T8, the last tergite and ovipositor sheaths brown. Wings hyaline; veins brown, pterostigma dark.

Male.

Unknown.

Host.

Unknown.

Material examined.

Holotype: ♀, Fengxi (116°15'E, 24°31'N ~ 116°17'E, 24°32'N), Meizhou, Guangdong, 2003. VII. 29, legs. Chen Jujian, No. 20048449.

Etymology.

The specific name “punctatiscutum” derives from the Latin adjective “punctate” and noun “scutum”, referring to disc of scutellum with large punctures.

Distribution.

China (Guangdong).

Remarks.

This species is similar to Diolcogaster austrina (Wilkinsonellus, 1929), but can be distinguished by the disc of scutellum with dense punctures, larger laterally (the latter with disc of scutellum smooth and highly polished); vein 1-CU1 much shorter than vein 2-CU1 (the latter with vein 1-CU1 and vein 2-CU1 of equal length); and antennae normal, long and thin (the latter with antennae short and stout).