Bodenheimer (Animal Life in Palestine, 1935) has this to say:
Leucopis griseola and its gongeners develop predaciously on aphids and coccids.

From Wikipedia:
Chamaemyiidae is a small family of acalyptrate flies with less than 200 species described worldwide. The larvae of these small flies are active and predatory and are often used for biological control of aphids, scale insects and similar pests. Chamaemyiid fossils are poorly represented in amber deposits but a few examples are known from the Eocene epoch onwards.
Very small flies, greyish or yellowish grey, heavily dusted, with complete wing venation.