Head of a horsefly (Tabanus bromius), macrophotograph. This is a large blood-sucking insect that feeds mainly on horses and cattle. Its large, sharp mouthparts (lower left) can be seen beneath its head. These mouthparts are used for penetrating the skin of its prey. Its saliva has anticoagulant properties, and wounds inflicted by this fly tend to be large, painful and long-lasting. Its huge compound eyes are seen at upper centre. Horseflies may reach lengths of around 25 millimetres, placing them amongst the largest of the flies. Magnification: x3.6 at 5x7cm size.