(Figures 3–6)

Hubei: ♂, Tiansanping (alt. 1700 m), Lücongpo, Badong, 16 July 2006, coll. Lijun Cai and Huifeng Zhou (NWAU).

Guizhou: 1♂ 1♀, Golden Top (alt. 2200 m), Mt Fanjingshan, 31 June 2001, coll. Caixia Gao (Light trap); 1♂, Dongpo, Mt Fanjingshan (alt. 1750 m), 1 August 2001, coll. Caixia Gao (Light trap); 1♂ 1♀, Golden Top (alt. 2000 m), Mt Fanjingshan, 1–2 August 2001, coll. Wanzhi Cai and Xinwei Niu (CAU). Hubei: 2♂♂ 1♀, Xuan’en, 30 July 1989, coll. Zuyao Liu (SHEM). 1♂ 1♀, Shennongjia (alt. 1600 m), 7 August 2011, coll. Jing Chen and Qionghua Gao (NWAU).

The specific epithet, setigerus, is of Latin derivation and refers to the long setae subapically on the ventral margin of the epandrial lobe.

Bittacus setigerus can be recognized mainly by a distinct row of blackish brown long setae on the sub-apex of the ventral margin of the epandrial lobe, and the brown clouding at OM, ORs, FRs and end of CuP, along three sectorial crossveins between veins R 2+3, R 3 and R 4 conspicuously. Av is absent. 1A ends slightly before FM.

Body length 17.5 mm; antennal length 8.5 mm; forewing length 22.1 mm, width 5.3 mm; hindwing length 19.2 mm, width 4.3 mm.

Head. Antennae filiform and ciliated; scape and pedicel yellowish brown; flagellum brown, 20-segmented. Vertex yellowish brown; rostrum dark brown basally, slightly paler distally; maxillary palpi dark brown; compound eyes blackish brown; ocellar triangle black.

Thorax. Pronotum, propleuron and prothoracic spiracle unevenly brown; pronotum with two setae along anterior and posterior margins, respectively; propleuron with sparse setae along anterior margin. Meso- and metanotum unevenly brown laterally, with a paler median stripe about as wide as scutellum; each scutellum with two setae along posterior margin; pleuron and sternum pale yellow. Posterior margin of each coxal cavity with a black streak. Legs pale brown with several setae. Bases of femora and two ends of tibiae blackish brown; basitarsus strikingly shorter than the whole length of tarsomeres II and III; tarsomere IV with one spine on each side.

Wings (Figure 3). Forewings pale yellow brown. Pterostigma distinct, darker than wing membrane. Brown conspicuous clouding at OM, ORs, FRs and end of CuP, along three sectorial crossveins between veins R 2+3, R 3 and R 4. The thyridium prominent at FM. Two brown nygmata each in cell R 4+5 and 1R 5. Two Pcv; Scv before FRs; Sc ending slightly beyond or at FRs; Cuv at FM; Av absent; 1A ending before FM; 2A ending before OM. Apical crossveins arranged roughly in an arcuate line along the crossvein s 1, and other crossveins not arranged in lines. Hindwings similar to forewings in markings, but Sc ending before FRs; Cuv slightly before FM; CuP coalesced with 1A at base.

Abdomen of male. Terga and sterna II–VIII darkening from yellow to brown; terga II– VIII each with a narrow black antecosta; tergum VIII deeply emarginate in a V-shape along posterior margin (Figure 5C). Epandrial lobes pale brown, slightly shorter than gonocoxite (Figure 5A), with some short black setae on median portion of inner side and near median portion of ventral margin (Figure 5D), and a row of blackish brown long setae subapically on the ventral margin (Figure 5C, D). Tergum X saddle-like, extending around the base of cerci to lateral side (Figure 5A, B). Upper branch of proctiger protruding from between the two epandrial lobes, strongly sclerotized laterally, slightly curved cephalad apically, with a bundle of long yellow setae at the posterior region of apex. Lower branch of proctiger elongate, with slender setae along margin, tapering toward apex (Figure 5A, B). Cercus subacute at apex, corresponding to half length of gonocoxite (Figures 4, 5A). Gonocoxite hemispherical, consisting of two halves, which are fused basally and separated by a V-shaped membranous area caudally (Figure 5E). Gonostylus short, bearing long setae, stout basally and pointed apically, with a glabrous sclerotized process medially (Figure 5E). Aedeagus broad basally, with a pair of short truncated aedeagal lobes (Figure 5E). Penisfilum long and coiled (Figure 5A).

Abdomen of female. Coloration of terga and sterna similar to male. Terga II–VI each with a narrow black antecosta on anterior margins; terga VII and IX each with a short and narrow antecosta, and tergum VIII with a long and broad antecosta, emarginate on posterior margin (Figure 6C); two lateral corners each connected to a dark brown sclerite whose ventral margin deeply emarginate in a V-shape (Figure 6A). A pointed dorsal process of subgenital plate extending into the emargination (Figure 6A, B); the subgenital plate irregular in shape, with two membranous emarginations along the lateral margin, and divided by a broad triangular membranous area into two halves, each of which bears a bundle of black setae at distal end; a spiracle in the front emargination (Figure 6A, B). Tergum X extremely narrow, usually extending ventrally (Figure 6A), but not extending ventrally in specimens collected from Fanjingshan. Anal plates yellowish brown and rounded apically, roughly as long as cerci (Figure 6A, C, D). Spermatheca swollen, constricted roughly at the middle (Figure 6E).

Hubei and Guizhou Provinces (China).

Bittacus setigerus sp. nov. is similar to B. tienmushana in wing patterns, but can be differentiated by 1A ending before FM. It also resembles B. strigatus in epandrial lobes, but is separated from the latter by a glabrous process on inner surface of the ventral apex.