Overview

The Hybotidae were segregated from the Empididae s.l. recently. See Chvala (1983) and Sinclair and Cumming (2000) for discussion.

Adult Hybotidae are often found along streams in various forested habitats, on leaves and seeps, although some taxa are associated with heathland vegetation and littoral habitats. Adults are predacious, and take various arthropod prey, although some visit flowers to take nectar, and some are know to feed on pollen (Chvala 1976). Adults of several species form 'relict' mating swarms (Chvala 1983).

Description

Body length 1-6 mm. Adults generally of stout build, and usually with brown to black and sometimes yellow cuticle. Head usually spherical, with large compound eyes, usually narrowly dichoptic in both sexes, but sometimes holoptic in both sexes. Antennae usually inserted in middle of head, scape small and bare, pedicel globular with circle of setae, and postpedicel 1-3-segmented, and often with arista like terminal segment. Proboscis short to elongate; palpus usually large and setose. Thorax strongly built; mesonotum sometimes greatly arched and domelike. Legs often raptorial. Fore tibia with distinctive ventral tubercle near base. Wings of varied shape, with Sc incomplete, costa ending at wing apex, Rs originating well distad of level of origin of crossvein h, R4+5 unbranched. Abdomen subcylindrical, usually elongate. Male terminalia rotated 45Deg to 90Deg to the right and often asymmetrical. Female oviscapt often with apical papillae.

The larvae are maggot-like and predacious, and occur in moist soil, decayed wood and other vegetation and dung, and in aquatic habitats (see Dyte 1967). Nothing is known of immature stages of the Australian fauna.

Distribution

The family Empididae comprises the following three subfamilies, all with representatives in Australia: Ocydromiinae, Hybotinae and Tachydromiinae. See Cumming & Sinclair (2000) for key to major groups.

Ocydromiinae. This subfamily includes Apterodromia , with four apterous and eight fully winged Australian species and other genera such as Ocydromia (Sinclair & Cumming 2000).

Hybotidae. Members of this subfamily often have a greatly arched mesonotum and holoptic eyes with enlarged dorsal facets on both sexes. The genera Hybos and Syneches occur in the Australian fauna.

Tachydromiinae. This subfamily has cell dm absent and neither R4+5 nor M forked so that all veins run without branching to the wing margin. The Australian fauna is highly speciose but almost totally undescribed. Two  narrow-bodied cursorial genera that rarely fly, Drapetis and Tachydromia , are frequently found on tree trunks and other vegetation. At least one undescribed species of Platypalpus , with large raptorial mid legs bearing an apical tibial spine, is known from females only, suggesting that it might be parthenogenetic.