RES Handbook Vol 10 Part 2c. Diptera. Pipunculidae

FLIES of the family Pipunculidae may be recognized by their strikingly large eyes, semiglobular or nearly globular and extremely mobile head, predominantly obscure coloration, and by their habit of hovering inconspicuously in low herbage, in hedgerows or among the foliage of various trees. Their wing venation most closely approaches that of the Syrphidae. They are mainly quite small, with an average wing length of around 4 mm; the smallest British species belong to the genus Oluilarus (range of wing lengths, 2~5-4·0 mm.), while the largest is the comparative "giant" of the family in Britain, Nephrocerus flavicornis Zetterstedt (range of wing length 7-9 mm.)