Latrodectus is a genus of spider in the family Theridiidae, many of which are commonly known as widow spiders. Individual species vary widely in size, but in most cases the females are dark and identifiable by reddish hourglass markings on the abdomen. The spiders' venomous bite is considered particularly dangerous because of the neurotoxin latrotoxin, which causes the condition latrodectism, both named for the genus. The female black widow has unusually large venom glands and her bite is particularly harmful to humans.
See Special:Whatlinkshere/Etymology:Black Widow for a list of articles using this term.