Hygiella angustifrons

Hiroshi Shima & Takuji Tachi, 2016, New species of Hygiella Mesnil (Diptera: Tachinidae), parasitoids of leaf insects (Phasmatodea: Phylliidae), Journal of Natural History 50 (25), pp. 1648-1668 : 1652-1657

Hygiella angustifrons sp. nov.

( Figures 1 A, C, 4A – E)

Description

Male. Head black in ground colour, dark brown on anterior portion of gena, with dense grey yellow-white pruinosity, darker on fronto-orbital plate; frontal vitta velvety brown; antenna brown/black; palpus red/yellow to red/brown. Vertex about one-seventh of head width; frontal vitta about twice, or slightly more, as wide as fronto-orbital plate at middle; parafacial weakly narrowed below, about two-thirds (about five-eighths in profile) as wide as first flagellomere at middle height; gena 0.28 (about 2/ 11 in profile) of eye height. Inner vertical seta slightly less than two-thirds of eye height; outer vertical seta absent; ocellar seta about two-thirds of inner vertical seta; one reclinate orbital seta, subequal in length to ocellar seta; eight or nine frontal setae, lowest seta nearly level with apex of pedicel; fronto-orbital plate with two or three rows of fine long hairs; facial ridge with several short setae on lower quarter; five subvibrissal setae; gena with many dense fine hairs on genal dilation mixed with two or three strong hairs on anterior portion; occiput with two or three rows of black hairs. Antenna falling short of lower margin of face by about half length of pedicel; pedicel with many short hairs and a long strong seta which is about twice as long as pedicel; first flagellomere about 3.5 times as long as pedicel; arista short pubescence on basal one-third and bare on apical two-thirds, thickened on basal one-sixth; second aristomere shorter than wide. Palpus rather weakly clavate, nearly as long as first flagellomere.

Thorax including scutellum black in ground colour, with rather dense grey/white pruinosity; scutum with five longitudinal vittae, median vitta absent on presutural area and outer vitta about twice as wide as inner vitta; pleura with thin grey pruinosity. Three presutural and three postsutural acrostichal setae; three presutural and three postsutural dorsocentral setae; one presutural and three postsutural intra-alar setae, first postsutural seta fine; three katepisternal setae, lower seta slightly shorter than anterior seta; anatergite with several fine short hairs; scutellum with four pairs of marginal setae, basal and subapical setae strong, almost twice as long as scutellum, subapical setae weakly divergent, lateral seta very fine and shorter than scutellum, apical setae 1.2 times as long as scutellum; distance between bases of subapical setae only slightly more than that between basal and subapical setae of corresponding side.

Wing hyaline, tinged with pale brown on basal and anterior portions and along veins; tegula and basicosta black; lower calypter brown. Costal spine short, about 1.5 times as long as costal setae; second costal sector haired below; basal node of vein R4+5 with three fine hairs dorsally and ventrally. Relative lengths of costal sectors second, third and fourth approximately as 2: 5: 3; vein M from dm-cu crossvein to its bend longer than distance between the bend and wing margin (4: 3).

Legs black; pulvilli pale yellow/white. Fore tibia with two posterior setae; mid tibia with two or three anterodorsal setae, if three setae present, then lowest seta fine, two posterodorsal and one ventral setae; hind tibia with a regular row of rather sparsely set anterodorsal setae, two stronger setae among them, four posterodorsal and three ventral setae. Claws and pulvilli subequal in length to fifth tarsomere.

Abdomen black in ground colour, thinly covered with grey/white pruinosity on third and fourth tergites, the pruinosity thinner on posterior portion of each tergite, middorsal longitudinal vitta distinct; fifth tergite with dense brown nap of short very fine close set hairs dorsally and ventrally, anterior and posterior margins and mid dorsal longitudinal portion narrowly polished. Syntergite 1 + 2 without median marginal setae; third tergite with a pair each of median marginal and lateral marginal setae; fourth and fifth tergites each with a row of marginal setae; fifth sternite with U-shaped posteromedian cleft on posterior half, posterior lobe with fine hairs on inner margin posteriorly.

Male terminalia. Cerci in dorsal view with anterior margin broadly excavated, outer lobe rounded basally and narrowed apically, median lobe straight and narrowly separated on apical two-fifths, in lateral view median lobe nearly straight and well narrowed posteriorly; surstylus in lateral view curved on apical third and narrowed to apex; basiphallus with apical epiphallus; distiphallus serrate on dorsal surface.

Female. Unknown.

Body length: 8.9 mm.

Holotype male, Yaojaping, 2400 – 2600 m, Nujang, Yunnan, China, 1 – 2.ix.1996, W.-x. Zhang ( IZCAS).

Etymology

The specific name is taken from the characteristically narrow frons of the male of this species, and is formed from the Latin angustus, meaning narrow, plus the Latin frons.

Distribution

China (Yunnan)

Remarks

This species is characterized by a narrow frons, only three postsutural dorsocentral setae, a pale brownish tinged wing and brown lower calypter. It is known only from the northeastern part of Yunnan Province, China.

Figures

Figure 1. Male head in dorsal view (A, B) and lateral view (C). (A, C) Hygiella angustifrons sp. nov. (B) Hygiella nigripes Mesnil. Scales: 1 mm.