Tsetse flies (genus Glossina) are large biting flies found in Africa that transmit the agents of African Sleeping sickness, Trypanosoma brucei rhodesiense, and Trypanosoma brucei gambiense. They also transmit animal trypanosomes. They can distinguished from other large flies by two features; they fold their wings completely when they are resting so that the wings overlap over their abdomens, and they have a long proboscis which extends directly forward and is attached by a distinct bulb to the bottom of their heads. Also, their wings have a large distinctive cells shaped like a hatchet. It is commonly called a "hatchet cell".