Latrodectus is a genus of spiders in the Theridiidae family, most commonly known as spider widows. The genus is comprised of 31 recognized species [2] distributed worldwide, including black North American widows (L. mactans, L. hesperus, and L. variolus), the African button spider, and Australian Redback spider. Species vary widely. In most cases, females are dark and easily recognizable with a reddish mark on the abdomen, which is often (but not always) an hourglass.
Although rarely fatal, or even serious, these venomous spider bites look very dangerous because of the neurotoxin latrotoxin, which causes latrodectism conditions, both named after the genus. Women's black widows have enormous toxic glands and their bites can be very harmful to humans. However, regardless of the genus fame, Latrodectus bites are rarely fatal. Only a female bite is harmful to humans.