Hemerodromia isochita , 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: 34-35

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Hemerodromia isochita

sp. nov.

Hemerodromia isochita  sp. nov.

( Figs 51, 52View FIGURES 51 – 52, 89View FIGURES 82 – 90)

Diagnosis. Thorax yellow with sharply defined broad blackish median stripe; scutellum and mediotergite blackish; prothoracic ‘collar’ broadly black dorsally. Wing with a short stub of vein CuA 2 present; cell bm+dm long, ending distinctly beyond level of R 1. Cercus with complex process on inner face with convoluted tip bearing 4 blunt spines largely orientated internally.

Description. Male: Body length 2.0 mm; wing length 1.8 mm. Head. Black, dusted greyish, strongest on upper occiput; antenna and mouthparts yellow, all setae whitish; one pair reclinate ocl; postocular setae uniseriate below, becoming 2–3 serial above where merging with and hardly distinguishable from two pairs small vtl and several fine setulae on vertex; frontal setulae apparently absent. Antenna with postpedicel 1.8 X long as wide, stylus slightly shorter; scape with distinct fine dorsal seta. Thorax. Dusted greyish. Scutum with broad brownish black median stripe, about as wide as prothoracic ‘collar’ anteriorly, becoming broader posteriorly, leaving postpronotal area and lateral margins broadly clear yellow, boundary between dark and yellow pattern quite sharply defined. Prothoracic ‘collar’ broadly on dorsum, scutellum, mediotergite and sometimes dorsal part of anatergite brownish black. Pleura clear yellow (but sometimes with meron and fused anepisternum + katepisternum somewhat dusky); sutures about laterotergite and base of halter blackish. All setae yellowish; minute apart from a pair of distinct sct and one smaller npl. Legs. Yellowish, apical tarsal segment hardly darker. C 1 ~ 1.2–1.3 X longer than distance between C 1 and C 2, all setulae minute excepting a few slightly longer apicals. F 1 ~ 1.2 X long as C 1, ~ 4– 5 X long as wide, very slightly constricted 0.2–0.4 from base; femoral formula ~ 7 / 16–19 / 16 –20+ 1–2 / 7, denticles black, rows converging apically; spines yellow, rather evenly long, not distinctly longer basally. T 1 ~ 0.7 X long as F 1, evenly curved, ventral face shallowly concave; with one row of ~ 15–19 sharply pointed spinose setae ventrally; ventroapical spur very weakly developed; a strong ventroapical apical erect black spinose seta present ~ 3 X long as limb is deep apically. Mid and hind legs slender with only small setulae, T 3 with a short row of small setae posterodorsally and a ‘comb’ of short setae posteroapically. Wing. Membrane with somewhat dark microtrichia but hyaline basally. Veins brownish yellow to blackish but whitish near base and C yellowish with posterior margin very narrowly dark. Marginal setulae pale yellow. R 2 + 3 evenly curved, joining C ~ 0.6 X distance between end of R 1 and R 4; length of C between ends of R 2 + 3 and R 4 quite long, ~ 1.8 X long as R 4. R 4 slightly S-shaped, angle with R 5 at extreme base ~ 80–90 °, becoming ~ 70–80 ° thereafter, joining C at ~ 90 °; R 5 ~ 2.2–2.4 X long as R 4; R 4 + 5 fork distal to M 1 + 2 fork by ~ 0.8 –1.0X length of R 4; R 5 and M 1 slightly curved, convergent distally; cell bm+dm long, ending distinctly beyond level of R 1. A distinct vestigial ‘stump’ of vein CuA 2 present. Halter pale yellowish white. Abdomen. Tergites 1 and 7 yellow, 2–6 and 8 black; sternites yellow; posterior marginal and discal setae small and fine except longer and brownish on tergite 8 posteriorly. Terminalia. Black with dark setae. Cercus elongate, extending as far as tip of epandrium in lateral view with 4–5 strong outstanding spinose setae dorsally on proximal 0.6 and numerous fine longish setae dorsally and on outer face ( Fig. 51View FIGURES 51 – 52); slightly in-turned distally with irregularly rounded blunt apex. A complex process situated along inner face of cercus along with convoluted tip bearing 4 blunt spines largely orientated internally ( Fig. 52View FIGURES 51 – 52). Epandrium moderately elongate subrectangular with a few distinct setae on outer face and 4–5 narrow elongate processes apically (specialised setae?). Hypandrium rather narrow, largely obscured by epandrium. Female: Similar to male.

Type material. HOLOTYPE ♂, THAILAND: Chiang Mai Province, Doi Phahompok NP, Doi Phaluang, 1,449 m, 20 ° 1.06 'N, 99 ° 9.581 'E, 14–21.ix. 2007, MT, P. Wongchai, [T 6164]( QSBG). PARATYPES: 4 ♂, 1 ♀, same data as holotype, 7–14.ix.2007, 7– 14.x.2007, 28.xi.– 5.xii. 2007; 1 ♂, same data as holotype, light trap 13– 14.vii. 2007, M. Sharkey & P. Wongprom; 1 ♂, Chiang Mai Province, Doi Phahompok NP, Kiewlom 1 /montane forest, 2,174 m, 20 ° 3.549 'N, 99 ° 8.552 'E, 28.i.– 7.ii. 2008, MT, P. Wongchai ( QSBG & NMWC).

Etymology. The specific epithet isochita  refers to this species’ similarity to H. chita Smith, 1965  from Nepal.

Remarks. The male terminalia are very similar to H. chita Smith, 1965  from Nepal in both colouration and form of cerci and epandrium. Both H. chita  and H. isochita  sp. nov. have a distinct ‘stump’ of vein CuA 2 present in the wing. Hemerodromia isochita  sp. nov. is known only from the mountain Doi Phahompok, Chiang Mai Province, northern Thailand ( Fig. 89View FIGURES 82 – 90). All but one of the 8 known specimens were taken in mid-elevation forest (1,449 m) from May to December with one captured in moist hill evergreen forest at 2,200 m in late January.


National Museum of Wales