Latrodectus geometricus is commonly known as the brown widow, grey widow, brown button spider, or geometric button spider. The brown widow is found in parts of the northeastern and southern United States (including Florida, Alabama, California, Louisiana, Mississippi, Georgia, Tennessee, and Texas); as well as in parts of Australia and South Africa.

L. geometricus is generally lighter in color than the black widow species; the color can range from tan to dark brown to black. Like the black widow, L. geometricus has a prominent "hourglass" marking on the underside of the abdomen. However, the brown widow's hourglass is usually an orange or a yellowish color.

Brown widow's hourglass is usually an orange or a yellowish color..

Black widow's hourglass is really red.

Like all Latrodectus species, L. geometricus has a medically significant neurotoxic venom. Dr. G.B. Edwards, a University of Florida arachnologist claims that brown widow venom is twice as potent as the black widow venom, but is usually confined to the bite area and surrounding tissue, as opposed to the Black widow. Other sources say that the brown widow is less venomous than L mactans. Regardless, people who have been bitten typically describe the spider bite symptoms as very painful and extreme care should be taken when working or playing in the areas they inhabit.
 

A sexually mature male spins a "sperm web", deposits semen on it, and charges his palpi with the sperm. The male then inserts his palpus into the female's epigyne. The female deposits her eggs in a globular silken container in which they remain camouflaged and guarded. A female black widow spider can produce four to nine egg sacs in one summer, each containing about 100-400 eggs. Usually, eggs incubate for twenty to thirty days. Rarely do more than one hundred survive through this process.  The females can live for up to five years, while a male's lifespan is much shorter. Contrary to popular belief, the female only rarely eats the male after mating, and L. mactans is the only black widow species for which this form of sexual cannibalism has been observed in the wild.

Black widows build irregular webs of coarse silk, usually near the ground in dark places, and usually outdoors. Webs are often built among leaf litter on the ground in deciduous forests. They are also found under rocks or logs, in wood piles, in mammal burrows, and in dark corners of sheds, garages, crawl spaces, cellars, and basements. The spiders hang in an inverted position in these webs.

I've only seen black widows on a few occasions, every time in a woodpile or wood litter outdoors, and they scared the shit out of me. Regular spiders give me the creeps, but these gals are rather large, and the thought they can deliver a dangerous bite did not help the situation. Nevertheless, I'm fascinated by them and have spent hours watching all types of spiders, usually close-up while I'm inches away. Unfortunately, I've not seen any widow spiders at all here near Chicago.