Genus Tachytrechus Haliday, 1851

(Fig. 15B)

DIVERSITY. — 9 species (3.5-4.5 mm).

MORPHOLOGY, ECOLOGY AND DISTRIBUTION

Rather large, metallic species with males often featuring modified fore tibiae or tarsi. Similar to the other Dolichopodinae, most of the Tachytrechus species (seven spp.) and specimens (n=61) were gathered by sweep net, whereas FITs produced six species (with only 12 specimens). This genus was collected at 11 sampling sites, including four of the six rocky outcrops. Tachytrechus species show an entirely different ecological profile than the other Mitaraka Dolichopodinae, and are generally not found in the centre of the palm swamps but rather occupy low vegetation overhanging running water (streams), fallen logs and wet rocks.Two species, Tachytrechus sp. GF-003 and T. sp. GF-005 (Fig. 15B), were only collected on bare rocks of ‘savanes roches’ and inselbergs, the latter species in large numbers.

Family ENLINIINAE Robinson, 1970