I wondered the same thing we have tons of them all over my yard from what I can tell it is a spittle bug or frog hopper ( Prosapia bicincta) I just looked it up on bug guide.net and wikipedia
What Black Bug Has Thin Orange Stripes On Its Back, It Is Oval Shaped As Well?
Most likely a cockroach. (hopefully its a hissing cockroach! Those are the friendly ones!) But that description can fit under many bugs...