The red on its back immediately caught my eye. Our building was sprayed with insecticide last week so I figure that's why he was out and about. Red Stripe Spider - Castianeira crocata.
The notorious Black Widow Spider (Latrodectus sp) of the United States is a close relative of the Redback Spider, and only differs in appearance by the absence of a red dorsal stripe.
The redback spider (Latrodectus hasseltii) is a highly venomous spider that is originally from Australia, although it has colonized other regions.Redback spiders are closely related to black widows and females of both species have red hourglass markings on their abdomens. Size: About the size of a U.S. quarter, with legs outstretched. Features: Prominent hind spinnerets: these are two, small, finger-like projections on the end of the grass spider's abdomen (used to spin the web).Many other spiders have spinnerets, but they are very large and distinctive in grass spiders. Redback spiders belong to the Family Theridiidae, which is found worldwide. Grass Spider. Color: Brown with prominent longitudinal gray or tan stripes. La Porte, Harris County, Texas, USA March 18, 2008 Size: Approximately 1" This guy was crawling around the floor at my work. The redback spider also has a red stripe on its back.