The widow spiders are members of the spider genus Latrodectus, in the family Theridiidae.

Latrodectus includes approximately 31 recognized venomous species, with the black widow spider (Latrodectus mactans) being the best known member of the group.

The female black widow's venom is particularly harmful to humans (males almost never bite humans).

Spiders of the genus Steatoda (also of the Theridiidae family) are often mistaken for widow spiders, and are known as false widow spiders.

The false widow spiders are significantly less harmful to humans.

For more information about the topic Widow spider, read the full article at Wikipedia.org, or see the following related articles:

Black widow spider — The black widow spider (Latrodectus spp.) is a spider notorious for its neurotoxic venom. It is a large widow spider found throughout the world and ...  > read more

Yellow sac spider — The Yellow sac spider (Cheiracanthium inclusum) is not a true sac spider but a long-legged sac spider. It is one of a handful of spiders in North ...  > read more

Hobo spider — The Hobo Spider (Tegenaria agrestis) is a member of the genus of spiders known colloquially as funnel web spiders. The spider's venom is strong ...  > read more

Brown recluse spider — The brown recluse spider is a venomous spider, Loxosceles reclusa. It is usually between 1/4 and 3/4 inch (6.4-19.1mm) but may grow larger. It is ...  > read more

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

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