I'm No Expert.......(2)
......but I think this is a male Black Widow Spider. Males have yellow and red bands and spots on the back. Adult male black widows are a quarter the size of the female, and are usually gray or brown rather than black and red; while they may sometimes have an hourglass marking on their ventral abdomen, it is usually yellow or white. Male black widows are not venomous, but this is as close as I wanted to get! These eight legged wonders occupy all four deserts located in the American Southwest and this one in our yard!! This is the underside of it. Then again this could be the brown widow???