Asteiidae

Asteiidae is a small but widespread family of acalyptrate flies or Diptera. About 130 species in 10 genera have been described worldwide.They are rarely collected.

Family description

For terms see Morphology of Diptera.

Adult asteiids are minute to small (1–3 millimeters) thin-bodied and delicate (often weakly sclerotized) flies, with yellow-black or dark colours.The wings are relatively long and transparent. The head is rounded, the male almost always with distinct interfrontal stripes. The arista may be bare or pubescent but usually has a zigzag of longer and shorter alternating rays. The postvertical bristles are weakly developed, divergent or parallel or totally absent. Ocellar bristles may be present or absent. There is one orbital bristle on each side of the frons (Shtakel'berg] (0–2 pairs of frontal bristles). Interfrontal bristles may be present as may scattered interfrontal setulae. Vibrissae may be absent or present. On the mesonotum are one to two pairs of dorsoscentral bristles. The costa is entire, without interruptions; the subcosta is reduced; posterior basal wing cell and discoidal wing cell are fused; anal cell of wing and anal vein of wing are absent. Tibiae lack a dorsal preapical bristle.