Scientific Name:  Latrodectus hesperus
Order:  Araneae
Family:  Theridiidae
Diet:  Eats insects that it traps in its web.
Vegetation Association:  They are common around man-made structures such as garages, woodpiles, or lawn furniture.
Predators:  Egg sacs are preyed upon by the flightless scelionid wasp and members of the chloropid fly genus.   Adults are preyed upon by a few wasps including the blue mad dauber and the spider wasp.
Life Stages:  The female mates only once in her lifetime, and lays about 300 eggs. The male is sometimes eaten by the female after mating. 
Notes:  Female has a distinctive red-orange hourglass marking on her underside. The male is less than half the size of the female.  They are shy, sedentary, and mostly nocturnal.   They can be potentially dangerous to humans.