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Solifugae (windscorpions; subphylum Chelicerata, class Arachnida) Order of arachnids in which the prosoma is divided into a proterosoma and two free segments. The abdomen is constricted, anteriad, and the entire body is covered with long, sensory hairs. The chelicerae are much enlarged, chelate, and armed with teeth. The pedipalps are leg-like, and their tarsi, as well as the tarsi of the first pair of walking legs, contain sensilla ampullacea. The carapace bears a large pair of median eyes and there may be vestiges of lateral eyes. The terminal segment of the last pair of walking legs bears racquet organs which contain sensory nerve endings. The tracheal system resembles that of the Insecta rather than Arachnida. Windscorpions have complex courtship behaviour, seemingly more advanced than that of scorpions but less advanced than that of spiders. Most species are crepuscular or nocturnal, and although none has specialized digging structures most of them construct burrows, and may aggregate in areas of high prey density, prey being caught by chase or ambush. Of the 800 or so species, six are found in Europe. Most, being desert-dwellers, are found in India, the W. Indies, western USA, and northern Mexico.