Hemerodromia flaviventris Yan

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 : 27-29

Hemerodromia flaviventris Yan g & Yan g

(Figs 1, 2, 40–42, 85)

Hemerodromia flaviventris Yang & Yang, 1991: 236 .

Diagnosis. Thorax yellow with scutum entirely black, hardly paler laterally or about notopleural area; scutellum, mediotergite, laterotergite and meron black. Wing with cell bm+dm short, ending as about level of R1. Male cercus with small inwardly directed subapical process on inner face.

Re-description. Male: Body length 2.8 mm; wing length 2.3 mm. Head. Black, dusted greyish, strongest on upper occiput; antenna and mouthparts yellowish white, all setae whitish; one pair reclinate ocl; postocular setae uniseriate, merging above with two pairs small vtl and numerous fine setulae on vertex; frontal setulae apparently absent. Antenna with postpedicel 1.5X long as wide, stylus of similar length; scape with distinct fine dorsal seta. Thorax. Dusted greyish. Scutum with ground colour black or brownish black, at most extreme lateral margin of postpronotal area yellow. Scutellum, mediotergite, laterotergite, anepimeron and meron black. Fused anepisternum + katepisternum dark yellowish with small triangular area below root of wing blackish; sometimes obscurely darkened ventrally (Fig. 1) Proepimeron blackish ventrally behind insertion point of front legs. All setae yellowish; minute apart from a pair of distinct sct and one smaller npl. Legs. Yellowish white, apical tarsal segment hardly darker. C1 ~ 1.2–1.3X 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, very slightly constricted 0.3 from base; femoral formula ~ 8/18– 20/17 –21+2/6–7, denticles black, rows converging apically; spines yellow (Fig. 2), pv row longer than av row, both rows becoming longer proximally. T1 ~ 0.7X long as F1, evenly curved, ventral face shallowly concave; with one row of ~ 22 sharply pointed spinose setae ventrally; ventroapical spur very weakly developed; a strong ventroapical erect black spinose seta present. Mid and hind legs slender with only small setulae; T1 with somewhat longer setulae dorsally on distal 0.5; 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 brownish to greyish black but whitish near base. Marginal setulae yellowish grey. R2+3 evenly curved, rather long joining C ~ 0.7–0.75X distance between end of R1 and R4; length of C between ends of R2+3 and R4 short, ~1.2X long as R4. R4 slightly S-shaped, angle with R5 at extreme base ~ 80–90°, becoming ~70–80° thereafter, joining C at ~ 90°; R5 ~ 2.2X long as R4, almost linear; R4+5 fork distal to M1+2 fork by ~ 1.2X length of R4. M1 almost linear beyond base, convergent distally with R5; cell bm+dm short, ending as about level of R1. Halter pale yellowish white. Abdomen. Black with tergites 1 and 7 and sternites 1–3 and 7 yellowish. 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. 40 ); broader proximally in dorsal view ( Fig. 41 ); with tip down-curved viewed laterally and a small inwardly directed subapical process on inner face ( Fig. 42 ). Epandrium elongate ovoid with strong setae on outer face ( Fig. 41 ). Hypandrium divided ventrobasally, fused ventroapically. Slender process with distal part emerging free between apex of cercus and epandrium; distally incurved, slightly inflated apically with 3–4 short tooth-like setae on inner face. Surstylus present, broad subovate, emerging beyond epandrial lamella; apical margin with inner face bearing numerous close-set inwardly directed setulae, becoming longer on pv margin. Female: similar to male but spines and denticles beneath F1 rather more numerous, femoral formula ~ 8/23/20–26 +2/7–8. Abdomen dorsally with only tergite 1 yellowish; vent more extensively yellowish, only sternite 1 on posterior margin, sternite 7 and terminalia blackish.

Material examined. THAILAND: 23 ♂, 9♀, Chiang Mai Province, Doi Inthanon NP, small stream in hill evergreen forest below Checkpoint 2, 1,650 m, 18.516°N, 98.483°E, 6.xii.2013, netted, A.R. Plant; Checkpoint 2, 1,611 m, 18.5208°N, 98.4997°E, 27.xi.2012, netted, A.R. Plant; Siriphum waterfall, 1,333 m, 18.5422°N, 98.5172°E, 23.xi.2012, netted, A.R. Plant; Pinus forest well below Checkpoint 2, 1,543 m, 18.5713°N, 99.0189°E, 23.xi.2012, netted, A.R. Plant; hill evergreen forest in Doi Inthanon NP [precise locality unrecorded], 27.xi.2012; 2♂, Chiang Mai Province, Doi Phahompok NP, Pinus kesiya forest, 1,476 m, 20.01722°N, 99.16166°E, 29.xi.2012, netted, A.R. Plant; 2♂, 1♀, Nan Province, Doi Phu Kha NP, hill evergreen forest, 1,141 m, 19.1836°N, 101.0816°E, 20.xi.2012, netted, A.R. Plant ( QSBG & NMWC).

Remarks. In darker individuals the dark ventral marking on the fused anepisternum + katepisternum is more pronounced forming a narrow blackish brown stripe along the lower part of the sclerites and sometimes the triangular dark patch under the root of the wing is enlarged to cover much of the posterior part of the pleura. Hemerodromia flaviventris was described from Guangxi, China ( Yang & Yang 1991). In Thailand it has been noted from predominantly evergreen and Pinus forest biotopes at 1,141–1,650 m at localities in Nan and Chiang Mai provinces, northern Thailand ( Fig. 85 ). It appears to favour small to medium-sized streams often in dense shade and adult emergence is apparently confined to November and December during the cool dry season.

Figures

FIGURES 40 – 42. Male terminalia of Hemerodromia flaviventris Yang & Ya ng 40, lateral view of terminalia; 41, dorsal view of cerci; 42, apex of left cercus in laterodorsal view. 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.