I'm almost certain this is an immature 'stink bug'. 99% on that, not sure of the scientific name. Smash it and we'll know for sure. I'm glad you snapped it before you send him to Boot Hill.
I no what this insect is it is a shield bug,it get it's name from the shape of it wing covers.Interesting looking photo and love the little white flowers in this photo as well.This insect is also know as a stink bug,take a look at this site. http://en.wikipedia.org/wiki/Shield_bug.