Holotype, ♀ (ZJUH), “S. China: Hunan, nr Zhangjiajie, Badagong Mts, Tian Ping Mt., 9-13.vii.2009, 550 m, Xi-Ying Li, RMNH’10”, “CVA4256, sp. 22”.

Vein 1r-m of hind wing about 0.4 times as long as vein 1-M (Fig. 287); posterior groove of pronotal side and anterior groove of metapleuron smooth (Fig. 286).

Holotype, ♀, length of body1.8 mm, of fore wing 2.1 mm.

Head. Antenna with 23 segments and 1.2 times as long as fore wing; third segment 1.4 times as long as fourth segment, length of third, fourth and penultimate segments 4.5, 3.2 and 2.2 times their width, respectively (Fig. 294); length of maxillary palp 1.1 times height of head; labial palp segments normal; occipital carina widely removed from hypostomal carina and dorsally absent (Fig. 292); hypostomal carina medium-sized; length of eye in dorsal view 2.3 times temple; frons slightly depressed behind antennal sockets and in front of anterior ocellus and glabrous, smooth; face smooth, medially elevated; width of clypeus 2.7 times its maximum height and 0.45 times width of face; clypeus rather convex but slightly protruding forwards and largely smooth (except for some punctures) and its ventral margin slightly concave and sharp (Fig. 291); hypoclypeal depression rather large (Fig. 291); malar suture deep; mandible triangular and with narrow ventral carina (Fig. 292).

Mesosoma. Length of mesosoma 1.2 times its height; dorsal pronope large, deep and round (Fig. 293); pronotal side smooth and posterior groove largely absent (Fig. 286); epicnemial area smooth dorsally; precoxal sulcus medially subvertical, deep and slightly finely crenulate (Fig. 286); rest of mesopleuron smooth; pleural sulcus smooth; mesosternal sulcus deep and moderately crenulate; anterior groove of metapleuron largely smooth; notauli absent on disc, only anteriorly with pair of short smooth impressions (Fig. 288); mesoscutum glabrous and strongly shiny; medio-posterior depression of mesoscutum absent; scutellar sulcus moderately crenulate; scutellum convex medially, smooth; propodeum with short medio-longitudinal carina and rugose anteriorly, surface posteriorly mainly superficially rugulose (Fig. 289).

Wings. Fore wing (Fig. 287): pterostigma elongate triangular; 1-R1 ending at wing apex and1.4 times as long as pterostigma; r:3-SR:SR1 = 2:25:62; 2-SR:3-SR:r-m = 17:25:7; r somewhat widened; 1-M slightly curved and SR1 straight; m-cu distinctly postfurcal; cu-a slightly postfurcal and 1-CU1 widened; first subdiscal cell closed, CU1b medium-sized; apical quarter of M+CU1 sclerotized. Hind wing (Fig. 287): M+CU:1-M:1r-m = 5:5:2; cu-a straight; m-cu present as faint unpigmented trace.

Legs. Length of femur, tibia and basitarsus of hind leg 4.2, 9.4 and 5.0 times as long as wide, respectively; hind femur with long and tibia with medium-sized setae (Fig. 290).

Metasoma. Length of first tergite 1.3 times its apical width, its surface evenly moderately convex and coarsely vermiculate, its dorsal carinae developed in basal 0.4 of tergite, straight (Fig. 289); second suture slightly indicated; second and third tergites superficially longitudinally rugulose (Fig. 289); length of setose part of ovipositor sheath 0.07 times fore wing and 0.2 times length of hind tibia (Figs 286, 293).

Colour. Black; antenna (but scapus yellowish laterally and ventrally), stemmaticum, head dorsally (except near eyes), first tergite, most of fourth and following tergites, ovipositor sheath and pterostigma dark brown; face, malar space, palpi, mandible and legs (but hind tarsus and telotarsi darkened) pale yellow; tegulae and veins brown; wing membrane subhyaline.

Molecular data.COI, 16S, 28S (CVA4256).

*China (Hunan).

Unknown.

Name derived from “semi” (Latin for “half”) and “planus” (Latin for “flat”), because of the rather flat clypeus.

Notes. The new species runs in the key by Chen and Weng (2005) to Phaedrotoma dimidia (Chen& Weng, 2005) comb. n. Phaedrotoma semiplanata differs by having the setose part of the ovipositor sheath 0.7 times as long as first tergite ((about 3 times in Phaedrotoma dimidia), the notauli largely absent on the mesoscutal disc and smooth (anterior half present on disc and crenulate) and the propodeum without a transverse carina or posterior areola (present).