Bluebottle fly. Coloured scanning electron micrograph (SEM) of the head and part of the body of a bluebottle or blow fly (Calliphora sp.). The fly has a proboscis for the ingestion of food. It is tipped with a sponging disc (left), with which they soak up liquid from plants, decaying matter or wounds on animals. Flies such as this may transmit diseases, particularly if they land on uncooked food. Magnification unknown.