BRACHYCERA, Muscomorpha Schizophora Acalyptratae, Opomyzoidea

Number of British species: 1

Size: S

Difficulty: 2

Small (2-5 mm), mainly dark coloured flies with an extensive grey pruinosity, pale tarsi and red eyes. Arista pubescent or with longer rays; ocelli present; Ocellar bristles reduced or absent; Postvertical bristles absent; 2 pairs of frontal bristles, the lower pair curving forward and slightly inward, the upper pair backward and further from the eye margin than the lower pair; interfrontal bristles absent; vibrissae present. Wing clear; costa with humeral and subcostal breaks; vein Sc thin but complete, veins Sc and R₁ reaching the costa separately, but just before they merge for a short distance or touch each other, apical part of vein Sc more pallid; crossvein BM-Cu absent; cell cup closed. Tibiae without dorsal preapical bristle.

The larvae of Aulacigaster live in sap exuding from wounds in deciduous and coniferous trees, where they feed on micro-organisms. The adults are usually found near the larval sites but are also attracted to other fermenting fluids or substrates; they are known to hibernate in sheltered places in forests.

Séguy (1934)