I was told they were sonora semiannulata... you'll have to duke it out with the "experts" in this forum, because this is where it was decided. :)
:Are you sure that is a semiannulatum? The pic below is of the S. s. blanchardi which is found in the Big Bend region of Texas. I find numerous other spp of Sonora which can be striped or unpatterned, but I've always figured the semiannulatum was banded.