Hemerodromia systoechon sp. nov. (Figs 7, 66, 67, 95) Diagnosis. Scutum black with lateral margins narrowly and postpronotal area yellowish; Prothoracic ‘collar’ dorsally, scutellum and mediotergite black; pleura yellowish but sutures about laterotergite and base of halter blackish. Wing with cell bm+dm long, ending distinctly beyond level of R1; distance between ends of R2+3 and R4 long, ~1.8X long as R4. Male cercus with distinctly spinose process on inner face. Description. Male: Body length 2.2–2.5 mm; wing length 1.8–2.2 mm. Head. Black, dusted greyish, strongest on upper occiput; antenna and mouthparts yellow; all setae whitish; one pair reclinate ocl; postocular setae uniseriate, merging with two pairs small vtl; a few very fine setulae behind vtl; 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 brown or brownish black, usually with markedly darker area posterolaterally immediately above root of wing (viewed laterodorsally, appearing somewhat triangular with posterior apex darker); lateral margin distinctly yellowish, becoming wider anteriorly to include postpronotal area, demarcation between brown and yellow parts well defined; posterior margins laterally, narrowly diffuse yellowish. Prothoracic ‘collar’ dorsally, scutellum and mediotergite black. Pleura yellow (Fig. 7), fused anepisternum + katepisternum and meron sometimes vaguely darkened ventrally; 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 white, apical tarsal segment hardly darker. C1 ~1.2X longer than distance between C1 and C2, all setulae minute excepting a few slightly longer apicals. F1 ~ 1.2X long as C1, ~ 4– 5 X long as wide, slightly constricted 0.2–0.4 from base; femoral formula ~ 5–7/18–20+1–2/16–20/6–7, denticles black, rows converging apically; spines yellow, longest basally with several additional distinct spines at base. T1 ~ 0.7X long as F1, evenly curved, ventral face shallowly concave; with one row of ~ 16–20 sharply pointed spinose setae ventrally; a very small bluntly pointed ventroapical spur with strong ventroapical erect black spinose seta arising from near its base. Mid and hind legs slender with only small setulae but mid metatarsus with somewhat longer setulae ventrally, T3 with a short row of small setae posterodorsally and a ‘comb’ of short setae posteroapically. Wing. Membrane with dark microtrichia but hyaline basally. Veins dark but whitish near base and C yellowish brown with posterior margin very narrowly black. Marginal setulae pale yellow. R2+3 slightly curved, joining C ~ 0.6–0.7X distance between end of R1 and R4; length of C between ends of R2+3 and R4 quite long, ~1.8X long as R4. R4 sublinear, only slightly Sshaped, angle with R5 at extreme base ~ 70°; R5 ~2.0–2.2X long as R4; R4+5 fork distal to M1+2 fork by ~ 1X length of R4; R5 and M1 slightly curved, convergent distally; cell bm+dm long, ending distinctly beyond level of R1. Halter pale yellowish white. Abdomen. Tergites black with tergite 1 yellow; vent blackish becoming progressively yellowish basally on sternites 1–3; tergites with only indistinct setulae on posterior margins, but long brown setae on tergite 8 posteriorly. Sternites with setae on posterior margins brownish, becoming longer on posterior segments where also present on disc. Terminalia. Black with dark setae. Cercus elongate, extending as far as tip of epandrium in lateral view (Fig. 66); broad proximally in dorsal view (Fig. 67); distinctly setose on outer face distally. Viewed dorsally an elongate inner process apparently originating from inner face of cercus bearing 5–6 short strong spines. Epandrium elongate, bluntly pointed apically, with 1–2 strong setae subapically and numerous smaller setae on distal 0.5. Hypandrium elongate hemispherical, with distinct setae posteroventrally. Female: Similar to male but F1 without additional yellow spines at base or spines indistinct; abdomen more extensively yellowish proximally on vent, often only darkened on sternites 6 laterally and 7 laterally and medially. Terminalia blackish. Type material. HOLOTYPE ♂, THAILAND: Chiang Mai Province, Doi Inthanon NP, Summit Marsh, 2,500 m, 18°35.361'N, 98°29.157'E, 22.vii.–2.viii.2006, MT, Y. Areeluck [T118](QSBG). PARATYPES: 2♂, 15♀, same data as holotype, 29.vi.–2.vii.2006, 15–22.vii.2006, 2–9.viii.2006, 15–22.iv.2007, 29.iv.–6.v.2007, 8–15.v.2007; 2 ♂, Summit Forest, 2,500 m, 18°35.361'N, 98°29.157'E, 15–22.iv.2007, MT, Y. Areeluck; 2♂, 5♀, Kew Maepan Trail, 2,200 m, 18°33.162'N, 98°28.81'E, 21–27.ix.2006, 29.iv.–6.v.2007, 1–8.v.2007, 8–15.v.2007, MT, Y. Areeluck; 1♂, Checkpoint 2, 1,700 m, 18°31.559'N, 98°29.941'E, 8–15.vii.2006, MT, Y. Areeluck; 6♂, 7♀, Summit trap3 (Angka), 2,545 m, 18°35'20.1"N, 98°29'05.3"E, 1.iv.–2.v.2014, 2–29.v.2014, MT, W. Srisuka et al.; 1♀, Summit trap1 (back of office), 2,534 m, 18°35'12.8"N, 98°29'14.2"E, 29.v.–1.vii.2014, MT, W. Srisuka et al.; 1 ♀, Checkpoint 2 trap1, 1,639 m, 18°31'39.5"N, 98°29'59.7"E, 2–29.v.2014, MT, W. Srisuka et al. (QSBG & NMWC). Etymology. The specific epithet is from the Greek systoechon (single row) in reference to the single row of ventral setulae on the front tibia. It is used as a noun in apposition. Remarks. The thoracic colour pattern of this species and H. acutata Grootaert, Yang & Saigusa is quite similar in some individuals, especially in females of the latter species in which the scutellum is dark. In such cases H. systoechon sp. nov. can be distinguished from H. acutata by having cell bm+dm long, obviously reaching beyond the apex of R1 (level with R 1 in H. acutata) and length of C between ends of R2+3 and R4 quite long, about 1.8X long as R4. Both H. acutata and H. systoechon sp. nov. have a single row of denticles ventrally on the front tibia. H. systoechon sp. nov. is only known from the mountain Doi Inthanon, Chiang Mai Province, northern Thailand (Fig. 95). 95% of specimens were captured at 2,200–2,500 m in moist hill evergreen forest or Rhododendron / Sphagnum biotopes close to the summit. All specimens have been taken between April and September (mostly April–July) thus adult phenology correlates with the late hot dry period and Southwest Monsoon rainy season.

Published as part of Plant, Adrian R., 2015, Diversity of Hemerodromia Meigen, 1822 (Diptera: Empididae) in Thailand, the tip of a tropical iceberg?, pp. 1-56 in Zootaxa 4039 (1) on pages 43-44, DOI: 10.11646/zootaxa.4039.1.1, http://zenodo.org/record/289932