Melophagus ovinus.  

The sheep ked.  
These flies are often known as keds or hippoboscids. They are medium sized wingless flies with the head not distinct from the thorax. The eyes are inconspicuous and the body covered with bristles and setae. They are not typical cyclorrhaphan flies because of the adaptations of the adults to an ectoparasitic life. Melophagus ovinus, the sheep ked, established itself in the cooler areas of the tropics and can be mistaken for a tick. However, only larval ticks have six legs and sheep keds are much larger than larval ticks; nymphal and adult ticks have eight legs, and in all ticks the body is not divided into head, thorax and abdomen.