Hemerodromia furcata Grootaert, Yang & Saigusa

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 : 29-31

Hemerodromia furcata Grootaert, Yang & Saigusa

( Figs 43–45 , 86 )

Hemerodromia furcata Grootaert, Yang & Saigusa, 2000: 77 .

Diagnosis. Thoracic dorsum blackish. Laterotergite, meron and a small area of fused anepisternum + katepisternum below root of wing black; pleura otherwise yellow. Halter black. Cercus apically bifurcate.

Re-description. Male: Body length 2.2–2.6 mm; wing length 1.7–1.8 mm. Head. Black, dusted greyish; antenna pale yellow to brownish, apex of stylus darker; mouthparts yellowish white; all setae pale; one pair reclinate ocl; postocular setae very small, uniseriate, merging above with two pairs small vtl and several fine setulae on vertex; frontal setulae apparently absent. Antenna with postpedicel 2.0–2.5X long as wide, stylus shorter; scape with distinct fine dorsal seta. Thorax. Dusted greyish. Scutum with ground colour dark yellowish brown to black, often somewhat more yellowish on postpronotal area. Anterior spiracle narrowly emarginated with elongate U-shaped black mark, opening posteriorly (clearly visible in paler specimens, more obscure in dark ones). Scutellum, mediotergite and laterotergite black; meron yellowish or considerably darkened, especially below. Fused anepisternum + katepisternum with yellow ground colour and small triangular area below root of wing blackish; sometimes obscurely darkened ventrally. Proepimeron darkened on pv margin. All setae yellowish; minute apart from a pair of distinct sct and one smaller npl. Legs. Variably whitish yellow to brown; sometimes entirely pale but in dark individuals C1 and C2 and extreme base of C1, proximal 0.3 of F2 and F3 pale. Tarsal segments 4 and 5 sometimes darkened. C1 rather short ~ 1.1X longer than distance between C1 and C2, all setulae minute excepting a few slightly longer apicals. F1 ~ 1.2X long as C1, ~ 5X long as wide, evenly inflated, hardly constricted on proximal 0.3; femoral formula ~ 7– 8 /22–28/24–30+1–2/6–7, denticles black, rows converging apically; spines yellow, pv and av rows similarly long, not becoming longer proximally. T1 ~ 0.7X long as F1, evenly curved, ventral face shallowly concave; with one row of ~ 15–19 sharply pointed spinose setae ventrally; ventroapical spur absent, a strong ventroapical erect black spinose seta present. Mid and hind legs slender with only small dark setulae; T3 with short row of small setae posterodorsally before tip and a ‘comb’ of short setae posteroapically. Wing. Membrane rather evenly covered with dark microtrichia but hyaline basally. Veins greyish to blackish but whitish near base; R2+3 and R4+5 often darker. Marginal setulae dark. R2+3 linear before tip, rather long joining C ~ 0.8X distance between end of R1 and R4; length of C between ends of R2+3 and R4 short, ~1.1X long as R4. R4 slightly S-shaped, angle with R5 at extreme base ~ 80°, becoming ~70–80° thereafter, joining C at ~ 80–90°; R5 ~ 2.2X long as R4, almost linear; R4+5 fork distal to M1+2 fork by ~ 1.5X length of R4. M1 almost linear beyond base, convergent distally with R5; cell bm+dm short, ending as about level of R1. Halter with knob black, stem sometimes paler. Abdomen. Black with tergites 1 and sternites 1–2 yellowish with dark posterior margins. Tergites with brownish hairs, sternites with yellowish hairs, very short on anterior segments becoming progressively longer on posterior segments. Terminalia. Black with dark setae. Cerci elongate, extending beyond tip of epandrium ( Fig. 43 ); apically bifurcate with upper process bearing strong setae ( Fig. 45 ), lower process longer with generally weaker setae except two inwardly curving bristles at extreme tip; basal part broader in dorsal view ( Fig. 44 ), with long fine posteriorly directed setae. Epandrium elongate subovate, rather evenly covered with setae on outer face. Epandrium extending beyond tip of hypandrium. Surstylus present, reaching just beyond tip of epandrium, bilobed; dorsal lobe broad with apex inflated, almost shoe-shaped, with minute denticles and setulae on inner face; ventral lobe narrow, slightly inflated and upturned apically, bearing distinct apical setae. Female: similar to male but abdomen with sternites 1–6 yellow; sternite 7 with some long dark hairs on disc.

Material examined. THAILAND: 52♂, 24♀, Chiang Rai Province, Khun Chae NP, Mae Tho Checkpoint, stream, 700 m, 19.0797°N, 99.4019°E, xi.2012, netted, A.R. Plant; Chiang Mai Province, Doi Suthep Pui NP, evergreen forest / stream, 18.802°N, 98.919°E, 28.xi.2012, netted, A.R. Plant; Doi Phahompok NP, Pinus kesiya forest, 1,476 m, 20.01722°N, 99.16166°E, 29.xi.2012, netted, A.R. Plant; Doi Chiang Dao Wildlife Sanctuary, 491 m, 19°24.278'N 98°55.311'E, 17–23.iii.2008, MT, Songkran & Apichart; Mae Hong Son Province, Tham Pla NP, Ban Huai Sai Kaw, 590 m, 19.5911°N, 98.0016°E, 24.x.2014, netted, A.R. Plant; Namtok Mae Surin NP, Ban Nong Kaew, stream in lower hill evergreen forest, 1,050 m, 18.9630°N, 98.0811°E, 25.x.2014, netted, A.R. Plant; Nan Province, Doi Phu Kha NP, stream in hill evergreen forest, 1,141 m, 19.1836°N, 101.0816°E, 20.xi.2012, netted, A.R. Plant; Loei Province, Phu Reua NP, Lead Phob w/f, 1,152 m, 17.4985°N, 101.3355°E, 27.xi.2013, netted, A.R. Plant; Chantaburi Province, Khao Kitchakut NP, HQ-Krathing w/f, 51 m, 12.8361°N, 102.1208°E, 1.vii.2008, 2.vii.2008, netted, A.R. Plant / TIGER Project; Surat Thani Province, Khao Sok NP, Bang Huaraed, 122 m, 8°54.555'N, 98°30.522'E, 28.x.–4.xi.2008, MT, Pongphan ( QSBG & NMWC).

Remarks. Hemerodromia furcata was described from Menglun in Yunnan, China by Grootaert et al. (2000) from a single male specimen. The male terminalia of H. furcata ( Grootaert et al. 2000, figs 16–18) appear to be extremely similar to those of H. menglunana Grootaert, Yang & Saigusa, 2000 ( Grootaert et al. 2000, figs 19–21) with only slight differences in the depth of forking in the dorsal process of the cercus and shape of the tip of the aedeagus. In their diagnoses of the two species, the authors mention only one distinguishing feature; that the thoracic dorsum of H. furcata is ‘black’ whereas in H. menglunana it is ‘yellow excepting scutellum and metanotum brown’. The paratype of H. menglunana was taken at the same locality and date as the only known specimen of H. furcata and the holotype was taken in the same locality 3 days earlier. Differences in thoracic coloration are commonplace in Hemerodromia and only occasionally of diagnostic utility; indeed, Thailand specimens of H. furcata studied here from Nan Province are considerably darker than those from elsewhere. Similarly, minor differences in the shape of the cercus are apparent in different specimens. Given that all the Chinese specimens of the two species were collected in the same place, mostly at the same time, and that minor differences in colour or genital morphology are generally of dubious taxonomic value, there can be little doubt that they are a single species. However, having not examined the type material of either species I refrain from proposing a formal synonymy here. In the present work I apply the name H. furcata rather than H. menglunana .

In Thailand, H. furcata is widely distributed, and most frequent in the north ( Fig. 86 ), occurring in a variety of mid to low elevation forest types at 51–1,476 m. Of 74 specimens examined, one was captured in March, 21 in July and 53 in October or November suggesting that peak adult activity may correlate with the start and end of the Southwest Monsoon rains.

Figures

FIGURES 43 – 45. Male terminalia of Hemerodromia furcata Grootaert, Yang & Yang. 43, lateral view of terminalia; 44, dorsal view of cerci; 45, apex of cercus. Abbreviations: cer = cerci, epa = epandrium, hyp = hypandrium, lsur = lower lobe of surstylus, usur = upper lobe of 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.