Carriage of Corynebacterium pyogenes by the cattle nuisance flies Hydrotaea irritans (Fallén) and Musca autumnalis (De Geer).

Two species of cattle-visiting Muscidae were experimentally contaminated with C. pyogenes, a pathogen involved in the aetiology of summer mastitis. Surface contamination persisted for at least 4 days. Since M. autumnalis would not feed on media containing C. pyogenes the bacterium did not persist internally. All C. pyogenes were eliminated from the gut of H. irritans in 4 days. H. irritans is thus more likely to transmit C. pyogenes than is M. autumnalis but only by mechanical transfer, and is not a true vector.