Seothyra, commonly known as the buckspoor spiders, buck spoor spiders or just spoor spiders, belong to a sand-dwelling, burrowing genus of araneomorph spiders in the family Eresidae. The 13 species are endemic to the arid, sandy flats and semistabilized red dunes of southern Africa. They are sexually dimorphic. The tiny males, which are seldom seen, imitate sugar ants or velvet ants in their appearance and habits, while the females hide in and hunt from their characteristic burrows. They are thermophilous, with males as well as females being most active on hot days.

Velvet spiders are a small group of spiders almost entirely limited to the Old World, with the exception of one species known from Brazil. In Europe, some are commonly called the ladybird spiders.