Hemerodromia deltalutea Plant, 2015, sp. nov.

Hemerodromia deltalutea sp. nov.

(Figs 26–28, 80)

Diagnosis. A yellow species with mediotergite obscured brownish and sutures at anterior margin of scutum, between lateral margin of scutum and fused anepisternum + katepisternum, at anterior and lateral margins of scutellum, at anterior margin of laterotergite and immediately anterior of posterior spiracle, very narrowly black. Sct present. Cell bm+dm long. Epandrium strongly concave on dorsal margin and surstylus with a ‘brush’ of very long black bristles apically.

Description. Male: Body length 2.8 mm; wing length 2.2 mm. Head. Black, dusted greyish, frons paler reddish black becoming paler still near base of antennae; antenna and mouthparts pale whitish yellow, all setae pale; one pair reclinate ocl; postocular setae uniseriate, becoming biserial below, merging above with 2–3 pairs small vtl hardly distinguishable from fine setulae on vertex and upper occiput; frontal setulae apparently absent. Antenna with postpedicel ~2.0X long as wide, a few minute outstanding setulae subapically, stylus slightly shorter than postpedicel; scape with distinct fine dorsal seta. Thorax. Dusted greyish. Ground colour yellow with mediotergite variably obscured brownish; sutures between prothoracic ‘collar’ and anterior margin of scutum, between lateral margin of scutum and fused anepisternum + katepisternum, at anterior and lateral margins of scutellum, at anterior margin of laterotergite and immediately anterior of posterior spiracle, very narrowly black. All setae yellowish; minute apart from a pair of distinct sct and one smaller npl. Legs. Whitish yellow. C1 ~1.2X longer than distance between C1 and C2, all setulae minute excepting a few slightly longer apicals and a posterior ciliation of fine proclinate hairs ~0.2X long as limb is deep. F1 ~ 1.2X long as C1, ~ 6X long as wide, evenly inflated, slightly constricted on proximal 0.2– 0.3; femoral formula ~ 6– 7 /17–20/17–20+2/6–7, denticles black, rows converging apically; spines yellow, pv and av rows similarly long, becoming somewhat longer proximally. T1 ~ 0.8X long as F1, evenly curved, ventral face shallowly concave; with one row of ~ 17 sharply pointed spinose setae ventrally; a very small yellow ventroapical spur with distinct ventroapical erect black or yellowish black spinose seta arising from near its base; a short ciliation of distinct proclinate hairs dorsally on distal 0.2. Mid and hind legs slender with only small pale setulae, somewhat longer dorsally on distal 0.3 of T3. Wing. Membrane slightly darkened by rather even covering of greyish brown microtrichia but hyaline basally. Veins brownish yellow, somewhat darker about base of R2+3, R4+5 and distal part of cell bm+dm but pale yellowish near base. Marginal setulae pale. R2+3 linear on proximal 0.5, gently curved beyond, joining C ~ 0.7X distance between end of R1 and R4; length of C between ends of R2+3 and R4 ~1.5–1.8X long as R4; R4 almost linear, only very vaguely Sshaped; R5 ~ 2.0–2.2X long as R4, almost linear; R4+5 fork distal to M1+2 fork by ~ 1.0–1.2X length of R4. M1 almost linear beyond base, convergent distally with R5; cell bm+dm moderately long, ending distinctly beyond tip of R1. Halter yellowish white. Abdomen. Yellow with tergites 4–6 entirely, 2–3 broadly on at least distal ~0.5 and 1 very narrowly on posterior margin black. Terminalia. Black or brownish-black with cercus paler, yellowish brown. Cercus (Figs 26, 27) of complex structure; about as long as epandrium; subtriangular in dorsal view. Apical lobe incurved; broad, sub-stellate or somewhat club-shaped in lateral view. Median lobe less strongly sclerotized, incurved, bearing a few fine bristly setae apically. Epandrium (Fig. 26) with dorsal margin strongly concave distally in lateral view; a short bluntly pointed dorsoapical projection appearing sharper and longer in posterior view. Surstylus present, emerging slightly beyond end of epandrium; with dense ciliation of black flattened specialised setae apically. Hypandrium rather triangular in ventral view (Fig. 28) with apex broadly rounded; very long black setae apically, becoming shorter and yellowish proximally, bare basally; fused ventroapically, divided ventrobasally. Female: Unknown.

Type material. HOLOTYPE ♂, THAILAND: Kamphaeng Phet Province, Mae Wong NP, Chong Yen, 1,306 m, 16°5.212'N, 99°6.576'E, 10–17.xii.2007, MT, C. Piluek & A. Inpuang [T6302](QSBG). PARATYPES: 5♂, same data as holotype, 10–17.xii.2007, 24–31.xii.2007, 7–14.i.2008 (QSBG & NMWC).

Additional material. Three female Hemerodromia specimens collected at the same locality as the holotype male on 24–31.xii.2007 and 7–14.i.2008 (QSBG) may belong to this species but could not be confidently be assigned to it.

Etymology. The specific epithet is a concatenation of the Latin luteus and the fourth letter of the Greek alphabet (delta). It is used as a noun in apposition.

Remarks. The ‘brush’ of very long black bristles on the surstylus is a character that readily distinguishes Hemerodromia deltalutea sp. nov. from other predominantly yellow species of the genus in Thailand. The species is only known from a single locality in hill evergreen forest at 1,306 m in Kamphaeng Phet Province in northern Thailand (Fig. 80) during December and January in the cool dry season.