Hemerodromia ocellata , Plant, Adrian R., 2015

Plant, Adrian R., 2015, Diversity of Hemerodromia Meigen, 1822 (Diptera: Empididae) in Thailand, the tip of a tropical iceberg?, Zootaxa 4039 (1), pp. 1-56: 37

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Hemerodromia ocellata

sp. nov.

Hemerodromia ocellata  sp. nov.

( Figs 55 –57View FIGURES 55 – 57, 91View FIGURES 91 – 98)

Diagnosis. A yellow species with mediotergite slightly obscured brownish. Posterior margin of scutum with well defined black ‘scutoscutellar eye’. Sct absent. Cell bm+dm short. Epandrium with cluster of strong bristles posteroventrally. Surstylus extending distinctly beyond tip of epandrium, upper process almost circular apically with minute dentate setulae on margins; lower process linear with two large leaf-shaped setae apically.

Description. Male: Body length 2.2 mm; wing length 1.7 mm. Head. Black, dusted greyish; antenna and mouthparts pale whitish yellow, all setae pale; one pair proclinate ocl; postocular setae uniseriate, merging above with 1–2 pairs small vtl and several fine setulae on vertex; frontal setulae apparently absent. Antenna with postpedicel ~ 3 X long as wide, a few minute outstanding setulae subapically; stylus shorter, ~ 0.3–0.4 X long as postpedicel; scape with distinct fine dorsal seta. Thorax. Dusted greyish. Ground colour yellow; mediotergite rather vaguely obscured brownish but with yellow colour evident, prothoracic ‘collar’ very narrowly darkened medially; anterior spiracle not distinctly emarginated above with small dark mark; ‘scutoscutellar eye’ strongly defined, black; sutures between prothoracic ‘collar’ and anterior margin of scutum, and at margins laterotergite blackish. All setae yellowish, minute, a pair of distinct npl, sct absent. Legs. Pale yellow. C 1 ~ 1.2 X longer than distance between C 1 and C 2, all setulae minute but with a few longer hairs dorsally. F 1 ~ 1.1 X long as C 1, ~ 6 X long as wide, evenly inflated, hardly constricted on proximal 0.3; femoral formula ~ 6 / 16 / 16 + 1 / 7, denticles black, rows converging apically; spines yellow, pv and av rows short, becoming somewhat longer proximally with basal spine longest. T 1 ~ 0.6–0.7 X long as F 1, evenly curved, ventral face shallowly concave; with ~ 16 similarly sized sharply pointed spinose setae ventrally; short ciliation of distinct proclinate hairs dorsally on distal 0.3; ventroapical spur very small with ventroapical erect black spinose seta arising from near its base. Mid and hind legs slender with only small pale setulae. Wing. Membrane distinctly darkened by yellowish brown microtrichia, hyaline basally. Veins blackish, hyaline basally, darker about base of R 2 + 3 and M 1 + 2 and posterior border of cell bm+dm; veins C, R 4 and distal 0.5 of R 2 + 3 yellowish. Marginal setulae pale. R 2 + 3 almost linear, joining C ~ 0.7 X distance between end of R 1 and R 4; length of C between ends of R 2 + 3 and R 4 ~ 1.1 X long as R 4; R 4 almost linear; R 5 ~ 2.1 X long as R 4, almost linear; R 4 + 5 fork distal to M 1 + 2 fork by ~ 1.2 X length of R 4. M 1 almost linear beyond base, convergent distally with R 5; cell bm+dm short, ending at tip of R 1. Halter yellowish white. Squama with margin greyish yellow. Abdomen. Yellow with tergites 2–6 blackish, tergite 2 laterally yellow; a few distinct hairs on posterior margins of distal segments. Terminalia. Black. Cercus elongate ( Figs 55, 56View FIGURES 55 – 57), extending beyond tip of epandrium, slightly inflated apically in lateral view; a small subapical thickening on inner face lacking strong seta. Epandrium ( Fig. 55View FIGURES 55 – 57) small subquadrate with posterior margin almost linear for a short distance; several very strong bristly setae near pv margin. Surstylus present, extending distinctly beyond tip of epandrium; almost circular apically with series of dense minute dentate setulae on inner margin ventrally and posteriorly. A narrow process emerging beyond tip of epandrium, below surstylus (possibly lower lobe of surstylus), slightly curved, with distinct leaf-like setulae at tip and preapically ( Fig. 57View FIGURES 55 – 57). Hypandrium very large, ~ 2 X long as epandrium ( Fig. 55View FIGURES 55 – 57); distinctly keel-shaped with few distinct bristles but distinctly pilose over much of its surface. Female: Unknown.

Type material. HOLOTYPE ♂, THAILAND: Surat Thani Province, Khao Sok NP, Bang Huaraed, 122 m, 8 ° 54.555 'N 98 ° 30.522 'E, 13–20.i. 2009, MT, Pongphan [T 3914]( QSBG).

Etymology. The specific epithet is from the Latin ocellata  (eye) in reference to the strongly defined ‘subscutellar eye’ marking.

Remarks. Hemerodromia ocellata  sp. nov. is very similar to H. anisoserrata  sp. nov. differing from it primarily in having a smaller epandrium, larger hypandrium, cercus somewhat narrower and lacking distinct setae on the subapical thickening of the inner face. The narrow process (lower process of surstylus?) emerging beyond the tip of epandrium is linear (sharply bent downwards at ~ 90 ° in H. anisoserrata  sp. nov.) and bears 2 strong leafshaped specialised setae at its apex. The species is also similar to H. serrata Saigusa & Yang 2002  . For further discussion of the differences between these three species see notes under H. anisoserrata  sp. nov. Hemerodromia ocellata  sp. nov. is only known from the holotype male taken in January at one lowland (122 m) locality in Surat Thani Province, southern Thailand ( Fig. 91View FIGURES 91 – 98).