Red-headed Mouse Spiders are found across the continent mainly west of the Great Dividing Range. Burrows are built with double or single trapdoors. 1-3 cm long. They have a glossy carapace and their head area is high and broad with bulbous jaws. Spinnerets, at the back of the abdomen, are short and blunt.
Females are black overall.
Male Eastern Mouse Spiders are black with a bluish white patch on the front of the abdomen. Male Red-headed Mouse Spiders have a red head and jaws, and gunmetal blue abdomen. Mouse spiders' eyes are widespread across the front of their head. Bite Mouse Spider venom may be very toxic, but only one serious envenomation has been recorded. Other bites have occurred causing minor effects.