The female Southern Black Widow spider is black with the red, hour-glass shaped marking on its back. The male--which is no danger to humans--has a red stripe on its back. And the Northern Black Widow has different markings all together.
Markings on Black Widow Spiders
1 of
A Northern Black Widow Spider
Marshal Hedin, via Wikimedia Commons
2 of
A Northern Black Widow Spider
Marshal Hedin, via Wikimedia Commons
3 of
A Southern Black Widow male.
Tanthalas39, via Wikimedia Commons
4 of
A Southern Black Widow male.
Tanthalas39, via Wikimedia Commons
