Tsetse fly

Tsetse (pronounced /ts/e-/ts/e, teet-SEE, or set-see) are large biting flies from Africa which live by feeding on the blood of vertebrate animals. Tsetse include all the species in the genus Glossina, which are generally placed in their own family, Glossinidae.

Tsetse have been extensively studied because they are biological vectors of the African trypanosomiases, deadly diseases which include sleeping sickness in people and nagana in cattle.

Tsetse are crudely similar to other large flies, such as the housefly, but can be distinguished by four characteristics of their anatomy, two of which are easy to observe. Tsetse fold their wings completely when they are resting so that one wing rests directly on top of the other over their abdomen. Tsetse also have a long proboscis which extends directly forward and is attached by a distinct bulb to the bottom of their head.

Tsetse have existed in the modern morphological form for at least 34 million years since fossil tsetse have been recovered from the Florissant Fossil Beds in Colorado.