Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Clickable Guide
Moths Butterflies Flies Caterpillars Flies Dragonflies Flies Mantids Cockroaches Bees and Wasps Walkingsticks Earwigs Ants Termites Hoppers and Kin Hoppers and Kin Beetles True Bugs Fleas Grasshoppers and Kin Ticks Spiders Scorpions Centipedes Millipedes


Guide Plate for the Southern Black Widow - Latrodectus mactans

Guide Plate for the Southern Black Widow - Latrodectus mactans
The female is on the left and the male is on the right.

Is the size comparison accurate?

On adult females the only red
On adult females the only red is on the hourglass. They have those red dots while they are maturing.

identification of L. mactans
This is a very good article but it still presents somewhat conflicting information about the identification of L. mactans.

The article says:
"The adult female black widow spider has a glossy jet black color all over, including body and legs. The only red marks are the bright red hourglass mark on the underside of the abdomen, and a red spot just behind and above the spinnerets."

But this diagram shows read marks on the dorsal side of the abdomen. I have seen some pictures where these marks are very distinctive. Do the marks disappear as the spider ages? Is this just a variation between individuals? Does L. mactans almost always have at least one read dot above the spinnerets?

Gut feeling
that the male is a bit smaller. I was amazed how small he was when I found one the other day. I thought it must be an immature male, but was ID's as mature.

Male Black Widow
I will make the male a bit smaller. Thanks for your help!

Comment viewing options
Select your preferred way to display the comments and click 'Save settings' to activate your changes.