Hemerodromia demissa, 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: 23-24

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Hemerodromia demissa

sp. nov

Hemerodromia demissa  sp. nov

( Figs 31 –33View FIGURES 31 – 33, 82View FIGURES 82 – 90)

Diagnosis. A reddish black species with preapical abdominal segments contrastingly yellow. 2 pairs of apical sct present. Distinguished from H. curvata Grootaert, Yang & Saigusa, 2000  primarily by differences in male terminalia with inner margin of cercus distally not serrate and a prominent apical downwardly directed process narrower with stronger serrations on its posterior margin.

Description. Male: Body length 2.5 mm; wing length 2.0 mm. Head. Black, dusted greyish. Antenna pale whitish yellow, scape and pedicel slightly darker, Mouthparts yellowish white. Vertex with only minute setulae (ocl apparently lost in types); postocular and lower occipital setulae minute. Antenna with postpedicel ~ 2.5 X long as wide, stylus ~ 0.5 X as long; scape with small dorsal seta. Thorax. Dark reddish brown to reddish black, slightly paler in postpronotal area, dusted greyish. All setae yellowish; minute apart from one small npl (anterior of which are a few very fine hairs); 4 very small apical sct.

Legs. Ground colour yellow including apical tarsomeres. C 1 ~ 1.1 X longer than distance between C 1 and C 2; all coxae with only minute setulae except for a few distinctly longer anteroapicals. F 1 ~ 1.1 X long as C 1, rather strongly inflated ~ 3.5 –4.0X long as wide, distinctly constricted 0.15 from base; femoral formula ~ 6– 7 / 15–18 / 12– 18 + 1–2 / 7; denticles black, rows converging apically, basal denticle of pv series stronger, positioned basal to constriction of limb; spines yellow, av spines longer than pv series. T 1 ~ 0.8 X long as F 1, evenly curved, ventral face shallowly concave; with 2 rows of ~ 16 sharply pointed spinose setae ventrally; ventroapical spur weakly developed; a strong ventroapical erect black spinose seta present. Mid and hind legs slender with only small setulae. Wing. Membrane usually slightly but distinctly darkened with brownish microtrichia but hyaline near extreme base. Veins brownish but paler near base. Marginal setulae brownish. R 2 + 3 linear, joining C ~ 0.8 X distance between end of R 1 and R 4; length of C between ends of R 2 + 3 and R 4 ~ 1.2 X long as R 4. R 4 almost linear, only slightly S-shaped, angle with R 5 at extreme base ~ 75–80 °; R 5 ~ 2.X long as R 4; R 4 + 5 fork distal to M 1 + 2 fork by ~ 1.5 X length of R 4; R 5 and M 1 almost linear, convergent distally; cell bm+dm short, ending at level of R 1. Halter entirely dirty whitish. Abdomen. Black dusted greyish but tergite 7 and sternites 7 and 8 contrastingly yellow or sometimes yellowish brown; all setulae black, small except some long yellow bristles posteriorly on sternites 7 and 8 and darker yellowish bristles on tergites 7 and 8. Terminalia. Black with dark setae. Cercus rather broad in lateral view ( Fig. 31View FIGURES 31 – 33), extending to tip of epandrium; a large broad (in lateral view) terminal process curved downwards bearing distinct serrations on posterior margin ( Fig. 33View FIGURES 31 – 33); an inwardly directed rather pointed apical process (in dorsal view) ( Fig. 32View FIGURES 31 – 33); inner margin of cercus otherwise lacking serrations or denticles. Epandrium bilobed distally; upper lobe short and blunt, bearing a few strong setae apically; lower lobe elongate, narrow with slightly expanded tip (surstylus?) incurved and bearing a few short spinose setae on inner margin. Hypandrium narrow and short, reaching only as far as tip of upper lobe of epandrium; aedeagus short, with hook-like lateral projection. Female: Unknown.

Type material. HOLOTYPE ♂, THAILAND: Chiang Mai Province, Doi Inthanon NP, Wachirathan trap 1, 662 m, 18.542 °N, 98.600 °E, 2–29.v. 2014, MT, W. Srisuka and R. Sawkord [QSBG- 2014 - 134 [( QSBG). PARATYPES: 2 ♂, 1 ♀, same data as holotype, 3–31.iii. 2014; Chiang Mai Province, Queen Sirikit Botanic Garden, deciduous forest, 620 m, 18.9007 °N, 98.8551 °E, 31.1.– 2.ii. 2007, flight interception trap, N. Buawangpong, J. Phasuk et al. ( QSBG & NMWC).

Etymology. The specific epithet demissa (Latin)  meaning dwelling in lowlands, refers to the lowland habitat in which this species has been found. It is used as a noun in apposition.

Remarks. Hemerodromia demissa  sp. nov. is clearly closely related to H. curvata  from Yunnan China, differing mostly in the shape of the distal processes of the cercus and small differences in shape of the tip of the lower epandrial process. Hemerodromia demissa  sp. nov. lacks a deeply serrate margin on the inner face of the cercus distally (see Grootaert et al. 2000, fig. 11 and Yang & Yang 2004, fig. 113) but instead has a single strong rather pointed, incurved process at the apex ( Fig. 32View FIGURES 31 – 33). Additionally the downcurved apical process of the cercus in H. curvata  is rather quadrate in lateral view (see Grootaert et al. 2000, fig. 10 and Yang & Yang 2004, fig. 112) whereas in H. demissa  sp. nov. it is more elongate, has stronger serrations on its posterior margin and its extreme apex is not produced dorsally ( Figs 31, 33View FIGURES 31 – 33). The thorax of H. curvata  is apparently black ( Grootaert et al. 2000) whereas it is more reddish brown or reddish black in H. demissa  sp. nov. The preapical abdominal segments of H. demissa  sp. nov. are distinctly yellow, contrasting with much darker segments on the rest of the abdomen. The species is known from lowland (620–662 m) deciduous and dry evergreen forest biotopes in Chiang Mai Province, northern Thailand ( Fig. 82View FIGURES 82 – 90). Adults were captured in February, March and May, coincident with the cool dry season.


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