Platypalpus Macquart 1827

Genus Platypalpus Macquart, 1827

Coryneta Meigen, 1800: 27. Type-species: Musca cursitans Fabricius, 1775, by subsequent designation of Engel (1939: 43). Suppressed by I.C.Z.N. 1963: 339 (Opinion 678).

Platypalpus Macquart, 1827: 92. Type-species: Musca cursitans Fabricius, 1775, by subsequent designation of Westwood (1840: 132).

Phoroxypha Rondani, 1856: 146. Type-species: Tachydromia longicornis Meigen, 1822, by original designation.

Cleptodromia Corti, 1907:101 (as subgenus of Tachydromia).Type-species: Tachydromia(Cleptodromia) longimana Corti, 1907 by monotypy.

Brevios Brunetti, 1913: 22. Type-species: B. longicornis Brunetti, 1913 by original designation (not in Yang et al. 2007).

Howlettia Brunetti, 1913: 23. Type-species: H. flavipes Brunetti, 1913 by monotypy. (not in Yang et al. 2007).

Tachydromia, authors, not Meigen, 1803, misidentifications.

Recognised by the following combination of characters: eyes separated in both sexes, bare; postpronotal lobe well differentiated; scutum usually distinctly longer than broad; mid leg raptorial, mid femur thickened and armed with rows of spine-like setae ventrally, mid tibia usually with more or less prominent apical spur; wing with veins A 1 and CuA 2 present (cell cup present).

Very small to large species with body size varying from about 1.0 to 5.0 mm. Eyes separated on frons and face, sometimes very narrowly; ommatidia of subequally small. One or two pairs of vertical bristles, sometimes not prominent. Ocellar tubercle with 2 pairs of bristles. Antenna with postpedicel conical; stylus apical. Palpus flattened, small, usually with some short subapical setae. Thorax greatly varying in ground-colour and degree of tomentosity from uniformly yellow to black and from largely shining to largely or entirely tomentose; scutum usually distinctly longer than broad; postpronotal lobe well differentiated; postpronotal bristle usually very prominent; mesonotal setation varying. Mid leg raptorial, mid femur thickened and armed with rows of spine-like setae ventrally, mid tibia usually with more or less prominent apical spur. Wings normally developed; without pattern; Rs rather long, originating beyond midway of vein R 1; vein R 1+2 long, meeting costa beyond wing midway; vein R 2+3 complete, meeting costa close to wing apex; A 1 present; crossvein CuA 2 present, recurrent; crossvein bm-cu oblique; cells br and bm of subequal length or cell bm slightly longer; cell cup present. Abdomen with segments 1-7 usually unmodified; no squamiform setae and gland-like intersegmental structures. Terminalia: epandrium not divided; left epandrial lamella separated from hypandrium; left surstylus undifferentiated from epandrial lamella; right epandrial lamella usually larger; right surstylus usually present, barely differentiated from epandrial lamella; cerci separated; hypandrium usually with 2 bristles on apical portion; phallus very short; two rod-shaped apodemes (i.e. ejaculatory plus ventral apodeme) present. Female usually similar to male in all respects except sexual differences; terminalia long; tergite 8 separated from sternite 8; cercus long, slender.

The genus Platypalpus is the largest group of Tachydromiinae and one of the most speciose genera of Empidoidea on the whole. Currently about 550 species of Platypalpus are known worldwide but about 75 % of them were described from the Palaearctic and Nearctic Regions (Yang et al. 2007). Platypalpus have been divided into several more or less natural species groups (Chvála 1975) and this classification of the genus is quite applicable to the Oriental representatives as well (Grootaert & Shamshev 2006).

In contrast to the Palaearctic Region, few species of Platypalpus are found in the Oriental Region at low altitudes. Having a similar habitat and niche as Elaphropeza, Platypalpus probably comes into competition with Elaphropeza that is likely more adapted to tropical conditions. However as soon as one samples at altitudes above 500 m, various species of Platypalpus are found and the number of Elaphropeza species drops.

After relatively intensive sampling in Singapore, only three females belonging to a single species of Platypalpus were found and we do not expect many more species to occur here. For a key and descriptions of the actually known Southeast Asian Platypalpus, we refer to Grootaert & Shamshev (2006). Although the species in Singapore is known from females only, we describe it since it has many distinct characters that make it easily recognisable from the single related species P. hualuang Grootaert & Shamshev described from Northeast Thailand and males are normally very similar in coloration and tomentosity.