Hemerodromia fusca Yang & Yang

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 : 31-32

Hemerodromia fusca Yang & Yang

( Figs 46, 47 , 87 )

Hemerodromia fusca Yang & Yang, 1986: 75 .

Diagnosis. A species with thorax black, legs and antennae variably blackish to yellowish. Front femur often darker. The male cercus is elongate in profile with a distinct dorsal process 0.5 from base. Surstylus extending beyond tip of epandrium, very conspicuously inflated apically where broadly T-shaped.

Re-description. Male: Body length 2.3 mm; wing length 2.0 mm. Head. Black, dusted brownish grey. Antenna sometimes entirely pale but often with scape and pedicel pale brown, postpedicel paler and stylus usually blackish. Mouthparts yellowish white with tip of proboscis brownish. One pair reclinate ocl; two pairs small vtl distinguishable from smaller fine hairs on vertex and upper occiput; postocular and lower occipital setulae minute. Antenna with postpedicel ~ 2X long as wide, stylus rather shorter; scape with distinct fine dorsal seta. Thorax. Black, dusted greyish. All setae yellowish; minute apart from one npl; sct absent but scutellum with a pair of very small erect setulae on disc. Legs. Ground colour variably whitish yellow to dark blackish brown; often front legs (especially C1 and/or F1) darker than others, sometimes only C1 dorsally darkened. C1 ~1.2X longer than distance between C1 and C2, all setulae minute except a few slightly longer dorsoapicals. C2 and C3 with a few fine setulae anteriorly. F1 ~ 1.1–1.2X long as C1, ~ 4– 5 X long as wide, not at all constricted 0.3 from base; femoral formula ~ 7– 10 /18–23/19–20+0–1/8–9, denticles black, rows converging apically; spines yellow, short, fine much shorter than limb is deep, longest basally, pv row somewhat longer than av row with basal spine of pv row longer still. T1 ~ 0.7X long as F1, evenly curved, ventral face shallowly concave; with 2 rows of ~19 sharply pointed spinose setae ventrally; ventroapical spur hardly developed; a strong ventroapical erect black spinose seta present. Mid and hind legs slender with only small setulae. Wing. Membrane usually conspicuously darkened with black microtrichia but hyaline basally. Veins blackish but whitish near base. Marginal setulae greyish. R2+3 linear, joining C ~ 0.7X distance between end of R1 and R4; length of C between ends of R2+3 and R4 ~1.2–1.4X long as R4. R4 almost linear, usually only slightly S-shaped, angle with R5 at extreme base ~ 70–80°, slightly swollen apically before junction with C; R5 ~2.0–2.2X long as R4; R4+5 fork distal to M1+2 fork by ~ 1.2–1.4X length of R4; R5 and M1 almost linear, convergent distally; cell bm+dm short, ending at level of R1. Halter variably blackish, paler on stem; sometimes entirely dirty white. Abdomen. Black dusted greyish but tergite 1 and occasionally tergite 2 paler; sternite 1 paler on disc, sternite 2 whitish with dark median line and posterolateral marks; all setulae black, small except posteriorly and laterally on sternite 7. Terminalia. Black with dark setae. Cercus moderately elongate in lateral view, extending beyond tip of epandrium ( Fig. 46 ), a shorter dorsal lobe originating ~0.5 from base (sometimes twisted internally and inconspicuous in lateral view) ( Fig. 47 ). Epandrium ( Fig. 46 ) bluntly pointed ovoid, with strong setae distally. Hypandrium, with distinct setae posteroventrally. Surstylus present, extending beyond tip of epandrium, very conspicuously inflated apically where broadly T-shaped with close set minute black setulae in inner face dorsally. Elongate process with 2 hook-like modified setae apical, emerging just beyond tip of epandrium. Female: Similar to male but F1 with basal spine of pv row much stronger, about as long as limb is deep. Abdomen with distinct setae on tergite 7 but all setae otherwise inconspicuous.

Material examined. 104♂, 102♀, Beung Kan, Chaiyaphum, Chantaburi, Chiang Mai, Kamphaeng Phet, Kanchanaburi, Khon Kaen, Lampang, Loei, Mukdahan, Nakhon Nayok, Nakhon Si Thammarat, Nan, Petchaburi and Surat Thani provinces ( QSBG, NMWC, INPA, MSU, MNHN). Note, 1 ♂, 1♀ removed for DNA sequence analysis ( INPA, MNHN); 24 specimens removed for population genetics studies ( MSU).

Remarks. This species is very similar to H. yunnanensis Yang & Yang, 1988 and also to H. phahompokensis sp. nov. from which it differs primarily in morphology of the male terminalia (see discussion under H. yunnanensis ). Hemerodromia fusca was described from Fujian, China ( Yang & Yang 1986) but is also known from Yunnan ( Grootaert et al. 2000) so may be widely distributed across southern China. The author and J. T. Câmara (pers. comm.) have also seen specimens of this species in collections from Vietnam but precise collection localities are not available. In Thailand H. fusca is present throughout the country ( Fig. 87 ), occurring in vicinity of streams and rivers in a variety of forest types and in irrigation channels in rice fields at 95–1,306 m. It has been taken in every month of the year but appears to be most abundant from September to March.

Figures

FIGURES 46 – 47. Male terminalia of Hemerodromia fusca Yang & Yang. 46, lateral view of terminalia; 47, dorsal view of cerci. Abbreviations: cer = cerci, epa = epandrium, hyp = hypandrium, sur = surstylus.

FIGURES 82 – 90. Distribution of Hemerodromia spp. in Thailand at a resolution of 0.25 ° and symbols sized to 0.5 ° of latitude and longitude. 82, H. demissa sp. nov.; 83, H. epsilutea sp. nov.; 84, H. etalutea sp. nov.; 85, H. flaviventris Yang & Yang; 86, H. furcata Grootaert, Yang & Saigusa; 87; H. fusca Yang & Yang; 88, H. gammalutea sp. nov.; 89, H. isochita sp. nov.; 90, H. namtokhinpoon sp. nov.