Key to male Cymatopus

and Thambemyia in Thailand

This key deals with marine dolichopodids from rocky shores with an apical arista on a triangular third antennal segment (postpedicel) and a pair of fronto-orbital bristles (bristle at each side of frons, halfway between base of antenna and vertex). For other marine dolichopodid genera, we refer to the key in Grootaert & Meuffels (2001).

1. Proboscis much shorter than eye height (Fig. 1) ..................... ...........................................................................2 ( Cymatopus)

– Proboscis much longer than eye height (Figs. 11, 12) ............ ................................................. Thambemyia pagdeni Oldroyd

2. Hind legs modified, hind tibia and first tarsomere with long hairs (Fig. 9) ............................................ C. longipilus Parent

– Hind legs simple without peculiar long hairs or bristles (Fig. 1) ..............................................................................................3

3. Wing with hind border deeply indented and with fields of longer microtrichia on wing membrane (Fig. 1, arrow); large species (> 2.5 mm).................................. C. malayensis Parent

– Wing simple, hind border not deeply indented, at most a little folded (Fig. 3, arrow); smaller species (2–2.5 mm) ..............4

4. Male with vein R 2+3 simple; fore tibia with a black twisted foliaceous anterior bristle near middle and a long black apical bristle (Fig. 6)...................... C. thaicus Grootaert & Meuffels

– Male with vein R 2+3 near middle much thickened and undulating, costa also thickened (Fig. 3); fore tibia without black anterior foliaceous bristle and without long apical bristle .................... ....................................................... C. mayakunae new species