Up To No Good

What fun I had watching the Shield Bugs/Stink Bugs on the arugula that's going to seed! It looked liked several instars (stages of development) were there all at once. The younger ones are rounder, and they gradually lengthen out  and assume the shield shape. The markings change as well. I'm not good enough at bug ID to figure out the exact name of these guys, but I'm afraid they are not, as they say in the bug game, beneficials.