Trachionus albitibialis Cui & van Achterberg

Cui, Qian, van Achterberg, Cornelis, Tan, Jiang-Li & Chen, Xue-Xin, 2015, The genus Trachionus Haliday, 1833 (Hymenoptera, Braconidae, Alysiinae) new for China, with description of four new species, ZooKeys 512, pp. 19-37 : 25

Taxon classification Animalia Hymenoptera Braconidae

Trachionus albitibialis Cui & van Achterberg sp. n. Figs 11, 12-21, 43

Type material.

Holotype, ♀ (NWUX), "NW. China: Shaanxi, Pingheliang, Ningshan, c. 2000 m, 27.vi.2011, 33°48'N, 108°50'E, Jiangli Tan, NWUX".

Diagnosis.

Scutellum largely smooth, at most punctulate and nearly flat; mandible mainly brown, flat, without crest and with small fourth and fifth teeth (Figs 17, 43); temple smooth (Fig. 18); propleuron with transverse carina subposteriorly; sternaulus absent; median groove of mesoscutum and notauli rather narrow posteriorly (Fig. 14); metanotal spine medium-sized, its highest point remaining below level of tips of setae of scutellum (Fig. 21); propodeum angularly lowered posteriorly in lateral view and carina hardly protruding postero-laterally (Fig. 14); transverse carina of propodeum indistinct or absent (Fig. 14); medial third of hind tibia ivory; basal half of second metasomal tergite strongly rugose-striate, with about 30 striae and very shiny, rugae of third tergite with indistinct interspaces. Similar to Trachionus hians , but that species has precoxal sulcus posteriorly and posterior part of notauli wide (rather narrow in Trachionus albitibialis ), basal half of hind tibia yellow (ivory) and basal half of second metasomal tergite largely finely aciculate (basal half of second tergite strongly rugose).

Description.

Holotype, female; body length 3.3 mm, forewing length 3.4 mm.

Head. Width of head twice its median length, head dorsally smooth, distinctly shiny and mostly sparsely setose; antenna with 31 (right) or 32 (left) segments, 1.1 × longer than forewing, third segment 1.4 × as long as fourth segment, length of third, fourth and penultimate segments 2.4 ×, 1.7 × and 1.6 × their width, respectively; frons with setae laterally and slightly depressed behind antennal sockets; eye in dorsal view 2.1 × as long as temple; temple in dorsal view directly roundly narrowed, smooth and near mandible punctulate and punctate; OOL: diameter of ocellus: POL = 14:4:5; face weakly convex, punctulate, with many upward pointing setae medially and downward pointing setae laterally; clypeus transverse, with fine punctures and convex; eye glabrous; mandible nearly touching eye, length of malar space 0.1 × basal width of mandible; mandible 1.3 × as long as its maximum width and 1.6 × as long as its basal width, mostly smooth, medially rugose; mandible with 4 teeth or lobes, and second one acute, wide triangular; maxillary palp 0.9 × as long as height of head.

Mesosoma. Length of mesosoma 1.4 × its height; pronotum laterally coarsely punctate, smooth dorsally and ventrally; propleuron with transverse carina subposteriorly; epicnemial area mostly coarsely punctate; precoxal sulcus complete, wide and distinctly punctate-crenulate; sternaulus absent; remainder of mesopleuron smooth and strongly shiny, but punctate dorsally; episternal scrobe large; pleural sulcus finely crenulate dorsally and coarser ventrally; mesosternal sulcus medium-sized and superficially crenulate, posteriorly punctate and with transverse rugae, but postpectal carina absent; metapleuron coarsely rugose-punctate; notauli rather narrow, completely punctate-crenulate and united medio-posteriorly; median groove of mesoscutum narrow posteriorly, punctate-crenulate; lateral lobes of mesoscutum smooth, shiny and glabrous, only anterior half of middle lobe and area near notauli setose; scutellar sulcus deep and with 4 longitudinal carinae, 0.4 × as long as scutellum; scutellum finely punctate, with lateral setae and nearly flat; propodeum angularly lowered posteriorly in lateral view and carina hardly protruding postero-laterally (Fig. 14); transverse carina of propodeum indistinct or absent (Fig. 14); surface of propodeum largely rugose-reticulate.

Wings. Pterostigma elliptical; marginal cell of forewing elongate; vein r issued before middle of pterostigma (Fig. 12); r:2-SR:3-SR+SR1 = 6:11:46; SR1 curved; 1-CU1:2-CU1 = 2:19; CU1b present; m-cu antefurcal; 1-CU1 wide. Hind wing: M+CU:1-M:1r-m = 15:7:8; cu-a straight; m-cu only slightly impressed.

Legs. Hind coxa largely smooth and with long setae; tarsal claws medium-sized (Fig. 20); length of femur, tibia and basitarsus of hind leg 3.7, 7.8 and 4.6 × their width, respectively; all femora widened.

Metasoma. Length of first tergite 0.8 × its apical width, its surface punctate-rugose, with dorsal carinae converging medially and united in distinct median carina (Fig. 15); second tergite rather coarsely rugose-striate; basal half of third tergite coarsely rugose-striate and strongly shiny, rugae of third tergite with indistinct interspaces, apical part of third tergite smooth and shiny; combined length of second and third tergites 0.7 × total length of metasoma (Fig. 16); setose part of ovipositor sheath 0.1 × as long as fore wing; hypopygium large and apically acute (Fig. 16).

Colour. Black; mandible reddish brown; palpi pale yellow; basal two thirds of hind tibia ivory and apex infuscate, and tarsi largely dark brown; tegula brown; humeral plate and remainder of legs yellow; hypopygium black medially and remainder largely yellowish; pterostigma and most veins dark brown; wing membrane slightly infuscate, but hind wing nearly pellucid.

Distribution.

China (Shaanxi).

Etymology.

The name is derived from “albus” (Latin for “white”) and “tibia” (Latin for “shinbone”) because of the largely whitish hind tibia.