Siobla leucocincta sp. nov.

(Plate 4)

Description. Holotype: Ψ.

Body length 12 mm. Body and legs black, 3rd to 8th abdominal tergites with feeble metallic luster; most of 5th antennomere and basal half of 6th antennomeres, most of 2nd abdominal tergite, small anterior spot on lateral side of 3rd abdominal tergite, and 2nd to 4th abdominal sternites, white; mandible except basal part, basal half of 1st antennomere, anterior corner and broad posterior margin of pronotum, orange brown; fore leg with outer side of coxa, femur, tibia and anterior side of basitarsus, dark yellow brown. Body hairs pale brown on dorsum of head and thorax, silver on venter of thorax and abdomen, hairs on mesoscutellum brown and on sheath pale brown. Wings hyaline, stigma and veins dark brown (Figs. 4a, b).

Clypeus densely and faintly punctured, interspaces shiny; front coarsely punctured with microsculptures; malar space densely microsculptured; temple with dense and larger punctures, interspaces narrow, shiny. Pronotum coarsely punctured with dense microsculpture, mesonotum densely punctured, with linear shiny interspaces; middle of mesoscutum with an oblique impunctate stripe; mesoscutellum densely punctured without interspaces, matt, scutellar appendage shiny; metascutellum densely punctured, interspaces feebly microsculptured; upper half of mesepisternum densely punctured, anepimeron, most of katepimeron, and middle of metapleuron microsculptured, posterior margin of katepimeron, posterior corner of metepimeron, and venter of metepisternum smooth, strongly shiny; venter of mesepisternum sparsely punctured, slightly shiny. First and 2nd tergites of abdomen smooth without punctures or microsculpture, other tergites feebly microsculptured, apical 4 to 5 tergites with shallow punctures.

Anterior margin of clypeus shallowly incised at middle; malar space as long as diameter of middle ocellus; inner margins of eyes distinctly convergent, shortest distance between eyes 1.2 times as long as eye height; middle fovea narrow and deep, lateral fovea small and deep; supra-antennal tubercles elevated, confluent with frontal ridges; frontal walls very narrow and fine; interocellar furrow distinct, postocellar furrow rather shallow; postocellar area slightly elevated, much lower than top of ocelli, wider than long as 10: 7; lateral furrows curved in middle, deep, parallel posteriorly; head behind eyes shorter than eyes in dorsal view (23: 28), lateral sides curved, posterior part distinctly convergent posteriorly; occipital carina sharp, complete (Fig. 4e). Antenna as long as abdomen, flagellum compressed, relative lengths of 3rd to 5th antennomeres as 19: 12: 11. Mesepisternum angularly elevated, with distinct corner; mesoscutellum roundly elevated, slightly higher than top of scutum, without carina; appendage flat. Relative lengths of inner tibial spur of hind leg and length of metabasitarsomere as 47: 100, Relative lengths of 1st tarsal pulvillus and 2nd tarsus of hind leg as 9: 37 (Fig. 4d). Hairs on temple as long as diameter of ocellus. Ovipositor longer than metabasitarsomere as 10: 7, sheath in lateral view distinctly longer than basal plate as 22: 15 (Fig. 4c). Lancet distinctly broadened just before apex, with 10 serrulae, middle serrulae each with 1 inner and 10–12 outer subbasal teeth (Figs. 4f, g).

Male: Unknown.

Variability: The antenna in the paratype is as long as the abdomen with the 5th and 6th antennomeres partly white on the outside; 1r-m is absent and the anal cross vein in the right forewing is absent.

Etymology: The specific epithet refers to the white middle antennomeres.

Specimens examined: Holotype: Ψ, Erlonghe, Mt. Liupan, Ningxia (35°23.380´N, 106°20.701´E), alt. 1945 m, 5 July, 2008, LIU Fei leg.; paratype: 1Ψ, same data as for holotype.

Distribution: China (Ningxia).

Remarks: See the above key for the differences between S. annulicornis. and S. leucocincta.

Siobla leucocincta (a). Female adult in dorsal view; (b). Female adult in lateral view; (c). Sheath in lateral view; (d). Hind tarsus; (e). Head of female in dorsal view; (f). Lancet; (g). Middle serrulae.