Mouse Spiders are spiders of the Genus Missulena, in the Mygalomorph family Actinopodidae. There are 11 known species in this Genus, all but one of which are indigenous to Australia. One species, M.tussulena, is found in Chile. The name derives from an old belief, now known to be false, that the spiders dig deep burrows similar to mice.
There is evidence that the bite of a Mouse Spider is potentially as serious as that of an Australasian Funnel-Web Spider; however recorded envenomations by this spider are rare. Funnel-Web anti-venom has been found to be an effective treatment for serious bites.