Thelyphonida Latreille, 1804 (as Thélyphone) Uropygi is an arachnid order comprising invertebrates commonly known as whip scorpions or vinegaroons (also spelled vinegarroons and vinegarones).

[a] Carl Linnaeus first described a whip scorpion in 1758, although he did not distinguish it from what are now regarded as different kinds of arachnid, calling it Phalangium caudatum.

[1] It means "tail rump", from Ancient Greek οὐροπύγιον (ouropygion),[7] from οὐρά (oura) "tail" and πυγή (pygē) "rump" referring to the whip-like flagellum on the end of the pygidium, a small plate made up of the last three segments of the abdominal exoskeleton.

Originally, Amblypygi (whip spiders), Uropygi and Schizomida (short-tailed whipscorpions) formed a single order of arachnids, Pedipalpi.

Phylogenetic studies show the three groups, Amblypygi, Uropygi s.s. and Schizomida, to be closely related.

[13] The prey is crushed between special teeth on the inside of the trochanters (the second segment of the "legs") of the front appendages.

Up to 40 eggs are extruded, within a membranous broodsac that preserves moisture and remains attached to the genital operculum and the fifth segment of the mother's ventral opisthosoma.

The female refuses to eat and holds her opisthosoma in an upward arch so that the broodsac does not touch the ground for the next few months, as the eggs develop into postembryos.

[21] The white young that hatch from the postembryos climb onto their mother's back and attach themselves there with special suckers.

Also, only a single species is known from Africa: Etienneus africanus, probably a Gondwana relict, endemic to Senegal, the Gambia and Guinea-Bissau.

Mastigoproctus giganteus, the giant whip scorpion, is found in more arid areas, including Arizona and New Mexico.