Bicaubittacus mengyangicus Tan & Hua, sp. nov.

(Figs 5–6)

Holotype: male, CHINA: YUNNAN: Xiaomengyang (alt. 1000 m), 6.V.1957, coll. Wang Shuyong; preserved in the Institute of Zoology, Chinese Academy of Sciences, Beijing [IZAS].

Paratypes: 2 ɗ, same data as holotype; 1 Ψ, Mt. Puwenlong (alt. 950 m), 8.V.1957, coll. Wang Shuyong [IZAS].

Etymology. The new species is named after its type locality, Mengyang, Yunnan Province.

Diagnosis. The new species is very similar to Bicaubittacus burmanus comb. nov. in appearance, but can be separated from the latter by the lower apical elongation of the male epandrial appendage, which is much longer and broader than the upper prong; the long distal prolongations of male gonocoxites with a row of distinct long black setae; flat, broad cerci with rounded apices; long, roughly L-shaped gonostylus.

Description. Body 15 mm long. Wingspan 37 mm. Forewing 17.8 mm long, 3.9 mm wide. Hindwing 15.1 mm long, 3.0 mm wide. Vertex blackish brown; frons and basal clypeus yellowish brown; distal clypeus, basal half of rostrum, maxillary and labial palps blackish brown; distal rostrum lighter, yellowish brown. Antennae filiform, about 7.8 mm long; scape and pedicel yellowish brown; flagellum ciliated, dark brown, with about 23 flagellomeres. Ocellar triangle blackish brown, slightly protuberant.

Pronotum unevenly dark brown; no distinct setae on the anterior margin. Mesonotum blackish brown for anterior two-thirds, with a narrow, paler, mid-longitudinal stripe gradually broadening posteriorly; the remaining part abruptly paler, yellowish brown. Metanotum dark brown laterally, with a paler mid longitudinal stripe as wide as scutellum. Pleura, coxae and mera yellowish brown, small black spot present on posterior margin of each coxa. Legs yellowish brown, with some short black setae on femora, tibiae and tarsi; femora and tibiae dark at apices; fourth tarsomere with a spine on each side.

Wings (Fig. 5 A) with hyaline membrane, tinted yellowish; four tiny clouding spots each at OM, ORs, FRs and subdistal CuP; pale brown along the distal margin and apical cross veins; pterostigma pale brown; thyridium at FM with distinct border. Forewing: Pcv 2; Av absent; Cuv ending at the level of FM; 1A terminating far before FM; Sc ending near FRs. Hindwing similar to forewing.

Abdomen of male with terga I–V yellowish brown; terga VI–VIII gradually darker; terga II–VIII each with narrow black antecosta; posterior margin of tergum VIII deeply emarginated, V-shaped. Epandrial appendages yellowish brown, large and highly modified (Figs 5 B, 6A), with an irregular basal process from the ventral margin curved ventrally into two triangles and extending caudally into a finger-shaped process (Fig. 6 A); distal margin strongly cleft into a short dorsal prong and a large ventral elongation (Figs 5 B, 6A, E); dorsal margin curved mesad, extending ventrad into a quadrangular process at about a quarter of their length (Figs 6 B–D); next to the process bearing a coarsely pointed process with 5–8 short black spines apically (Figs 6 A–D); beyond the level of the pointed process, dorsal margin of epandrial appendages curved strongly, distally bearing numerous short black spines mesally (Fig. 6 E). Gonocoxites elongate, prolonged distally into a pair of slender, weakly sclerotized, setiferous projections with a row of long black setae along the distal part (Figs 5 B, 6A, G). Gonostylus long, slightly bent ventrad at distal third, tapering toward apex, subbasally with a large mesal process ornamented with a brush of hairs along the dorsal margin (Figs 5 B, 6F, H). Cerci flat, broad, with apex rounded (Figs 5 B, 6A). Upper branch of proctiger long, with a dorsal subapical tuft of hairs; apex emarginated into two unequal processes, roughly L-shaped (Figs 5 B, 6A). Aedeagus relatively small, with subtriangular penunci on each side at base; penisfilum short and coiled (Figs 6 A, H).

Distribution. China (Yunnan).