Members of the order Solifugae, usually referred to as solifuges, solifugids, solpugids or by an assortment of vernacular names (e.g., camel spiders, false spiders, haarskeerders, jagspinnekoppe, jerrymanders, roman spiders, sun spiders, walzenspinnen, wind scorpions), are a diverse and fascinating, yet poorly known, order of specialized, mostly nocturnal, cursorial hunting arachnids notable for their massively powerful two-segmented chelicerae, voracious appetite, and tremendous speed.
They constitute the sixth most diverse order of arachnids in number of families, genera, and species. Many solifuges are able to run at extremely fast speeds (53 cm/sec) for short bursts, but like most arachnids, cannot sustain such rapid locomotion for long periods. Solifuges vary from a few millimeters to 10 centimeters in length and look superficially like stout, hairy, fast-running spiders with an extra pair of legs (leg-like, sensory pedipalps, held out in front of the body).
Ammotrechidae
Ceromidae
Daesiidae
Eremobatidae
Galeodidae
Gylippidae
Hexisopodidae
Karschiidae
Melanoblossidae
Mummuciidae
Rhagodidae
Solpugidae
Source: http://www.solpugid.com/Introduction.htm