The common name for spiders in the genus Sicarius, also called crab spiders for their vaguely crablike appearance. They are not related to the small, flower-dwelling crab spiders found in Europe and North America. There are sand spider species in Africa and South America. Both groups hunt by hiding in the sand and ambushing passing insects and arachnids. The African six-eyed sand spider is believed to be dangerous to man, but the venom of the South American species has not been extensively studied.