Billaea malayana Malloch 1929

Billaea malayana Malloch, 1929

Fig. 100

Billaea malayana Malloch, 1929: 340.— Crosskey 1976: 177 (catalog).— Crosskey 1977: 601 (catalog).

Diagnosis. Facial carina developed, arista long plumose, 4 presutural and 4 postsutural dorsocentral setae, abdominal tergites 3 and 4 with narrow transverse black bands not interrupted by pruinose band expanded from anterior portion.

Redescription. Body length 11.7 mm.

Male. Head. Pale yellowish gray-white pruinosity, fronto-orbital plate more grayish; lunule yellow; antenna with scape and pedicel reddish yellow, flagellomere 1 brown, arista yellow; palpus reddish yellow. Vertex about 0.23 of head width; frontal vitta widened anteriorly, slightly more than twice width of fronto-orbital plate at middle; parafacial about 2.5 times as wide as flagellomere 1 at middle height; face rather well concave, facial carina developed, high and long, continuous to forwardly protruded lower margin of face, longer than antenna; genal height about 0.39 of eye height; occiput weakly bulged. Inner vertical seta less than 1/2 of eye height; ocellar seta 2/3 as long as inner vertical seta; fronto-orbital plate with dense, fine short hairs which do not descend below level of lunule; lowest frontal seta nearly level of middle lunule. Antenna short, flagellomere 1 about 2.8 times as long as pedicel; arista short, slightly shorter than antenna, rather long plumose, total width including plumosity about 1.5 times as wide as flagellomere. Palpus slightly widened at apex, about 1.5 times as long as antenna.

Thorax. Black in ground color, postalar callus brown, scutum with dense pale yellowish gray-white pruinosity; 2 rather broad and obscure outer longitudinal dark vittae on dorsum, which are widely separated by transverse suture, and 3 narrow obscure inner vittae on anterior 1/2 of presutural area; scutellum black on basal 1/3. Five to six postpronotal setae, 3 basal setae arranged nearly in a straight line or median seta slightly set forward; 2 presutural and 4 postsutural acrostichal setae; 4 presutural and 4 postsutural dorsocentral setae; 3 postsutural intraalar setae; 4 supra-alar setae; 2 katepisternal setae. Wing. Hyaline, tegula and basicosta black, lower calypter white. Relative lengths of 2nd, 3rd and 4th costal sectors approximately as 2:3:1.5, vein M from dm-cu crossvein to its bend about twice distance between the bend and wing margin, bend of vein M with very short appendix. Legs. Black. Fore tibia with 2 posterior setae; mid tibia with 3 anterodorsal, 3 posterodorsal and 2 ventral setae; hind tibia with a row of closely set anterodorsal setae, 1 posterodorsal and 2–3 ventral setae, strong submedian seta absent among row of anterodorsal setae. Fore claws and pulvilli shorter than 5th tarsomere.

Abdomen. Ovate, reddish brown on sides of tergites 2 to 4, dorsum with dense pale yellowish gray pruinosity on anterior 2/3 of tergites 3, 3/5 of tergite 4 and 2/3 of tergite 5, posterior transverse black band of tergites 3 to 5 narrowed laterally and medially by pruinosity expanded from anterior pruinose portion. Hairs fine, dense, short and recumbent on dorsum of tergite 3, slightly sparser on tergite 4 and finer and erect on tergite 5; syntergite 1+2 with 1 lateral marginal seta, without median marginal setae; tergite 3 with 2 short median marginal and lateral setae.

Type material examined. Holotype ♂ of Billaea malayana Malloch, MALAYSIA, Kedah Peak (101°00′E, 6°00′N), 3950 feet, Malaya, 25.iii.1928 (BMNH).

Distribution. Malaysia.

Remarks. This species very much resembles the European species B. maritima (Schiner, 1862), which is not treated in this paper, and differs from it only in the longer plumosity of the arista and transverse black bands of the abdominal tergites. This species is known only from the holotype male and the male terminalia are not examined.