Billaea robusta Malloch 1935
Creators: name: Zhang, Chun-Tian
name: Shima, Hiroshi
name: Wang, Qiang
name: Tschorsnig, Hans-Peter
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Tachinidae
Billaea
Billaea robusta

description: Billaea robusta Malloch, 1935
Fig. 101
Billaea robusta Malloch, 1935: 674.— Crosskey 1976: 177 (catalog).— Crosskey 1977: 601 (catalog).
Diagnosis. Arista plumose, fore tibia with 1 posterior seta and abdominal tergites 3 and 4 each with a pair of triangular dark markings which are fused on posterior portion to a transverse band.
Redescription. Body length 13.5 mm.
Male. Head. With dense pale yellowish gray-white pruinosity; occipital dilation and occiput more whitish; antenna with scape, pedicel and basal 1/2–1/3 of flagellomere 1 reddish yellow, apical portion brown, arista reddish brown; palpus reddish yellow. Vertex about 0.19 of head width; frontal vitta strongly widened anteriorly, about 1.5 times as wide as fronto-orbital plate at middle; parafacial 2–2.5 times as wide as flagellomere 1 at middle height; face rather weakly concave, facial carina weak and short, at most 2/3 as long as antenna, lower margin well warped forward; genal height 0.4–0.45 of eye height; occiput weakly bulged. Inner vertical seta slightly shorter than 1/2 of eye height; ocellar seta fine, about 1/2 as long as inner vertical seta; lowest frontal seta nearly level with base of antenna; fronto-orbital plate with dense fine rather long hairs, of which 1–2 descend just below lowest frontal seta; gena with very dense fine short hairs. Flagellomere 1 about 3.5 times as long as pedicel; arista plumose, total width including plumosity subequal in length to flagellomere 1.
Thorax. Black in ground color, with dense grayish white pruinosity on scutum, 2 outer broad and 2 inner rather narrow longitudinal black vittae on presutural area, and 3 broad longitudinal vittae on postsutural scutum, the inner vittae of presutural area extending posteriorly to anterior 1/3 of postsutural scutum widening posteriorly; scutellum black on basal 2/3, covered with grayish pruinosity at apex. Postpronotal lobe with 3 setae, middle seta only slightly set forward; 1 presutural and 2 postsutural acrostichal setae; 3 presutural and 4 postsutural dorsocentral setae; 2 postsutural intra-alar setae; 4 supra-alar setae; 2 katepisternal setae. Wing. Hyaline, distinctly tinged with brown from base to level of bm-cu crossvein and pale brownish on anterior portion and along veins; tegula and basicosta black; lower calypter white. Relative lengths of 2nd, 3rd and 4th costal sectors approximately as 3:3.5:1.5; vein M from dm-cu crossvein to its bend about 1.5 times distance between the bend and wing margin. Legs. Black; pulvilli pale brownish. Fore tibia with 1 posterior seta; mid tibia with 2 anterodorsal, 2 posterodorsal and 1 ventral setae; hind tibia with a row of very closely set anterodorsal setae, 1 posterodorsal and 1 ventral seta. Fore claws and pulvilli shorter than 5th tarsomere.
Abdomen. Black, broadly reddish brown on sides of tergites 3 and 4, dorsum with dense whitish pruinosity on anterior 2/3 of tergites 3 to 5, the pruinose band triangularly narrowed on both sides of each tergite. Hairs on dorsum very dense, fine, short and suberect, erect and finer on tergite 5; syntergite 1+2 and tergite 3 without median and lateral marginal setae; tergite 5 at most with a row of fine hair-like marginal setae.
Type material examined. Holotype ♂ of Billaea robusta Malloch, MALAYSIA, Pine Tree Hill (101°41′E, 3°41′N), Fraser’s Hill 4600 ft., Papahng, 3.vii.1933 (BMNH).
Distribution. Malaysia (Malaya).
Remarks. This species is one of five species with bare parafacial, 4 or 5 narrow dark longitudinal on presutural scutum and a pair of triangular black markings on each tergites 3 and 4, the other species being B. atkinsoni, B. chinensis, B. steini and B. triangulifera. Within this group of five species, B. robusta and B.chinensis are the only two with one posterior seta on fore tibia and sides of tergites 3 and 4 broadly reddish brown. Billaea robusta differs from the latter in having short plumose arista, scutellum black on basal 2/3, the triangular dark markings on abdominal tergites 3 and 4 merged forming a dark band, and syntergite 1+2 and tergite 3 without lateral marginal setae.
description: Published as part of Zhang, Chun-Tian, Shima, Hiroshi, Wang, Qiang & Tschorsnig, Hans-Peter, 2015, A review of Billaea Robineau-Desvoidy of the eastern Palearctic and Oriental regions (Diptera: Tachinidae), pp. 1-40 in Zootaxa 3949 (1) on pages 21-22, DOI: 10.11646/zootaxa.3949.1.1, http://zenodo.org/record/288389