A review of the genus Brachystoma Meigen, 1822 in Europe (Diptera, Brachystomatidae) with a discussion of possible oviposition behaviour

On the basis of recently collected material, the genus Brachystoma Meigen, 1822 (Brachystomatidae Melander, 1908) is revised in Europe. Two species, B. vesiculosum (Fabricius, 1794) and B. obscuripes Loew, 1856 are recognized, redescribed, illustrated, with their DNA barcode sequence provided. Tergite 7 of Brachystoma females is considerably developed and forms a vesicle which encloses the segments which are normally posterior to it as well as the cerci. Many recently collected female specimens of B. obscuripes show a vesicle filled with soil particles and possibly mucus. We postulate that the female collects soil particles that are mixed with eggs and mucus in this vesicle. Hence the eggs would be protected after deposition; a similar behaviour is well known in some bee flies (family Bombyliidae Latreille, 1802).