Xynobius chrysops, Wu & Achterberg & Sheng & Chen, 2018

Wu, Qiong, Achterberg, Cornelis van, Sheng, Ying-yi & Chen, Xue-xin, 2018, A new genus from Vietnam (Hymenoptera, Braconidae, Opiinae), and the description of two new species, Journal of Hymenoptera Research 66, pp. 1-13 : 1

Xynobius chrysops sp. n.

Figs 12-14 , 15-23

Type material.

Holotype, ♀ ( RMNH), "NW. Vietnam: Tonkin, Hoang Lien N.R. , 15 km W [of] Sa Pa, c. 1900 m, 15-21.x.1999, Malaise traps, C. v. Achterberg, RMNH’99” .

Description.

Holotype, ♀, length of body 3.3 mm, of fore wing 3.6 mm.

Head. Antenna with 35 segments, bristly setose and 1.3 times as long as fore wing; third segment 1.1 times as long as fourth segment, length of third, fourth and penultimate segments 5.0, 4.5 and 2.3 times their width, respectively (Figs 12 , 22 ); length of maxillary palp 1.2 times height of head; length of eye in dorsal view as long as temple (Fig. 21 ); temple in dorsal view shiny, smooth, temple and vertex with adpressed setae; OOL: diameter of ocellus: POL= 1:1:3; face sparsely punctate, with a medio-longitudinal ridge extending to level of antennal sockets (Fig. 20 ); frons glabrous behind antennal sockets; in front of anterior ocellus shiny, smooth and glabrous but laterally setose (Fig. 20 ); labrum invisible; clypeus nearly semi-circular, with some oblique striae, convex but flattened ventrally, and its ventral margin truncate and narrow (Fig. 20 ); clypeus 2.1 times wider than its maximum height and 0.6 times wider than face; hypoclypeal depression narrow, slit-shaped; mandible straight ventrally, hardly twisted, apically gradually narrowed and second tooth small; mandible and with narrow ventral carina (Fig. 20 ); occipital carina remains far removed from hypostomal carina ventrally and horizontal dorsally, narrowly interrupted medio-dorsally; hypostomal carina narrow; malar suture distinct, narrow; length of malar space 0.9 times basal width of mandible.

Mesosoma. Length of mesosoma 1.5 times its height; dorsal pronope minute, round, (Figs 18 , 21 ); pronotal side largely smooth, but crenulate dorso-anteriorly and densely setose anteriorly and posteriorly (Figs 12 , 17 ); propleuron slightly convex, finely punctate and setose; epicnemial area densely setose dorsally, finely crenulate in groove ventrally; only anterior half of precoxal sulcus present, medium-sized and distinctly crenulate (Fig. 17 ); remainder of mesopleuron smooth and shiny; pleural sulcus distinctly crenulate; mesosternal sulcus moderately deep, narrow and crenulate; postpectal carina absent; mesoscutum very shiny, finely punctate, with golden setae and smooth interspaces (Figs 13 , 18 ); notauli only anteriorly impressed, deep, narrow and crenulate and largely absent on disc; medio-posterior depression of mesoscutum droplet-shaped (Fig. 13 ); scutellar sulcus deep and with 4 short crenulae, parallel-sided medially; scutellum convex and smooth, finely punctate and densely setose (Fig. 14 ); side of scutellum and axilla densely golden setose, and lateral axillar lamella very wide (Figs 13 , 14 ); metanotum glabrous medially and densely setose laterally; antero-dorsal part of propodeum densely setose, rugose near transverse ridge and with medio-longitudinal carina; posterior part of propodeum largely smooth, and with 4 long and curved carinae (Fig. 14 ).

Wings. Fore wing: 1-SR distinctly longer than wide and nearly linear with 1-M (Fig. 15 ); pterostigma wide triangular; 1-R1 ending at wing apex and twice as long as pterostigma; r long and connected with 3-SR by obtuse angle; r:3-SR:SR1 = 6:33:58; 2-SR:3-SR:r-m = 8:11:4; 1-M slightly curved and SR1 straight; m-cu distinctly postfurcal and straight; cu-a distinctly postfurcal and 1- CU 1 slightly widened;1- CU 1:2- CU 1=1:18; first subdiscal cell closed and CU 1b medium-sized; entire M+ CU 1 sclerotized (Fig, 17). Hind wing: 1-M of hind wing straight, resulting in subparallel-sided cell apically; M+ CU:1-M:1r-m = 30:34:15; cu-a straight; m-cu unsclerotized, spectral; SR absent (Fig. 16 ).

Legs. Length of femur, tibia and basitarsus of hind leg 4.1, 7.8 and 9.0 times as long as width, respectively (Fig. 23 ); femur with long setae, tarsus and tibia densely setose; hind tibia slender medially; dorsally hind tibia with large smooth and glabrous patch subbasally (Fig. 23 ).

Metasoma. Length of first tergite 1.7 times to its apical width, convex, its surface irregularly rugose medially (Fig. 19 ), dorsal carinae strong and combined in its basal third and area below widely depressed, but dorsope small; second suture almost invisible; basal depressions of second tergite minute and tergite as long as third tergite, both with wide setose bands (Fig. 19 ); second and following tergites smooth, shiny and setose posteriorly, especially densely in third tergite; combined length of second and third metasomal tergites 0.4 times total length of metasoma; setose part of ovipositor sheath 0.07 times as long as fore wing (exposed sheath 0.11 times), 0.6 times first tergite (entire sheath as long as tergite), and 0.2 times hind tibia (entire sheath 0.4 times); hypopygium about 0.3 times as long as metasoma, truncate apically and not reaching apex of metasoma (Fig. 23 ).

Colour. Blackish brown, but scape, pedicellus, mandible (but teeth dark), tegulae, fore coxa dorsally, fore femur laterally and ventrally, fore tibia basally, trochantellus dorsally, second tergite laterally yellowish brown; ventral margin of clypeus, pterostigma and veins, markings of fore wing near veins r, 1-SR+M, 2-SR, basal half of 3-SR, m-cu, basal of second discal cell and second subdiscal cell, fore femur dorsally, trochanter dorsally, tarsus (but pale basally), second tergite medially and following tergites dark brown; palpi, inner side of fore coxae, trochanter ventrally, middle and hind tibia basally pale yellowish; setae on vertex, temple, mesoscutum, scutellum, side of scutellum and metanotum golden, remainder of setae silvery; remainder of fore wing membrane subhyaline.

Distribution.

Vietnam.

Biology.

Unknown.

Notes.

This aberrantly coloured new species belongs to a small group of Asian spp. near Xynobius maculipennis (Enderlein, 1912) united by the subbasally widened hind tibia with the resulting small knob glabrous and shiny dorsally, the hypopygium dark brown, the head and mesoscutum densely pubescent, and the fore wing with a large Y-shaped dark brown area below para- and pterostigma (Fig. 15 ). The new species differs from all other species examined by having the third metasomal tergite with a wide band of setae apically (Fig. 19 ; narrow in other species); fore wing infuscate apically (Fig. 15 ; subhyaline); the hypoclypeal depression nearly absent (distinct); the head and mesosoma dark golden pubescent combined with a slender first tergite (slightly widened apically and 1.6 × longer than its apical width; other species have usually pale yellowish or silvery pubescence, if dark golden than first tergite 1.2-1.3 times as long as wide apically).

Etymology.

Named after the partly golden setosity; “chrysops” is Greek for “gold-coloured”.

Figures

Figures 12 - 14. Xynobius chrysops sp. n., ♀, holotype. 12 habitus, lateral aspect 13 scutellum and posterior half of mesoscutum, dorsal aspect 14 metanotum and propodeum, dorsal aspect.

Figures 15 - 23. Xynobius chrysops sp. n., ♀, holotype. 15 fore wing 16 hind wing 17 mesosoma, lateral aspect 18 head and mesosoma, dorsal aspect 19 propodeum and first-third metasomal tergites, dorsal aspect 20 head, anterior aspect 21 head, dorsal aspect 22 antenna 23 hind leg, lateral aspect.