Tachydromia, Shamshev, Igor & Grootaert, Patrick, 2009

Shamshev, Igor & Grootaert, Patrick, 2009, Two New Species Of The Genus Tachydromia Meigen (Diptera: Hybotidae) From Malaysia, Raffles Bulletin of Zoology 57 (2), pp. 251-254 : 253

Tachydromia pahangiensis, new species

Material examined. – Holotype – female, MALAYSIA: Pahang, Brinchang , 24 Nov.–2 Dec. 1977, coll. B. Bendell [ CNC].

Diagnosis. – Recognised by silvery white flattened setae on occiput, black body and legs, wings almost entirely uniformly brownish infuscate and halters with yellow knob.

Description. – Female. Body about 2.3 mm, wing 2.8 mm. Head black. Eyes extending beyond ocellar tubercle and almost touching on vertex. Frons short, narrow, pollinose, almost parallel-sided. Ocellar tubercle pollinose, ocellars minute. Occiput entirely pollinose, bearing 2 moderately long closely set black verticals, 2 similar setae and some scattered dark setulae on upper part, covered with numerous silvery white flattened setae on lower part closer to neck and mouth-opening. Antenna brown, postpedicel short, subtriangular; stylus apical, very long, short pubescent. Proboscis brown. Palpus small, truncate, transparent, almost lacking pubescence, with 1 very long subapical seta and some pale yellow setulae.

Thorax black, prosternum and anterior margin of proepisternum finely greyish tomentose, antepronotum, postpronotal lobe (except outer face), scutum, scutellum, mediotergite, meron (= hypopleuron) and laterotergite (= metapleuron) finely brownish tomentose, otherwise thorax shining. Postpronotal lobe very large, lacking conspicuous setae. Mesonotum with 2 subequally strong, moderately long black notopleurals and 4 scutellars (apical pair shorter than notopleurals, lateral pair minute); acrostichal and dorsocentral setae minute, the former arranged in 3–4 irregular rows, lacking on prescutellar depression; the latter uniserial.

Legs long, slender, largely shining, almost entirely black, knees of fore legs, hind tibiae broadly before middle (but except narrow space basally), fore and mid tarsomeres 1–2, hind basitarsus (except apex) and most part of hind tarsomere 2 (except apex) yellow. Fore coxa subshining, finely tomentose anteriorly, shining laterally, with numerous unmodified dark setae anteriorly. Fore femur strongly thickened, whitish pubescent ventrally, with several black anteroventral spinules on about basal half. Fore tibia somewhat spindle-shaped, with row of ventral spinules. Fore basitarsus with ventral spinules. Mid femur slender, with rows of black anteroventral and posteroventral setae becoming longer basally. Mid tibia with hardly prominent ventral spinules, lacking subapical projection. Hind leg very long and slender, without prominent setae. Mid and hind basitarsi with unmodified setation.

Wing normally developed, almost uniformly brownish infuscate, darker anteriorly, paler near base. Costal seta short. Vein R 1 meeting costa somewhat beyond wing midway. Proximal section of vein R 4+5 considerably longer than Rs. Veins R 4+5 and M 1+2 parallel toward wing-apex. Crossveins r-m and bm-cu separated. Cells br and bm extending to wing midway. Halter with yellowish knob and brownish stem.

Abdomen black, subshining, with scattered setae longer laterally. Cercus long, slender, brown.

Male. Unknown.

Etymology. – The epithet refers to the type locality, Pahang.

Distribution and seasonal occurrence. – Malaysia. Known from a single locality in Pahang Province. The record is from the end of November to the beginning of December.

Remarks. – The relationships of T. pahangiensis are unclear beyond inclusion within the T. luang species group. In having silvery white flattened setae on occiput, largely shining thorax, black legs, almost entirely uniformly brownish infuscate wings and halters with yellow knob the new species can be readily distinguished from all other species of the T. luang group, which are currently known from the Orient (Shamshev & Grootaert, 2008).