Galactic Insect?

While walking in the yard with the puppies, I noticed a little sparkle something on a dogwood leaf. This small shield like bug has great colors and an interesting pattern on its back. It almost seems to be wearing armor made of green and yellow. Are the colors there to help it blend into the surroundings or does it change as it gets older? Perplexing isn't it? I love the mystery of it all and since it reminded me of a space helmet worn in one of the sci-fi movies, I just had to take a photo. If anyone know what this bug is, please leave me a comment, I would appreciate it very much!