White-tailed (or white-tipped) spiders have a dull black, elongate body with a distinctive white spot at the end of the abdomen. Females have a plump abdomen and grow up to 20 mm long, while males are thinner and grow to about 12 mm long.
Adult white-tailed spiders have reddish legs and two pairs of faint white spots on the top of the abdomen. Young spiders have striped legs with more distinct white spots which fade with age.
They are commonly found in homes and other buildings, although their natural habitat is under rocks, fallen timber and bark in gardens and bushland.
Bites were commonly thought to cause necrosis of the skin but recent studies have found that most problems are caused by infection of the bite area. Some bites may still cause weeping of the wound for some time afterwards, as my brother, after a recent bite in Sydney, suffered from an open wound to his foot and a lengthy course of antibiotics to sustain the spread of the infection. He is still in discomfort after six months.