Prepare for battle. Above answer is correct. They start as a patch of bright yellow eggs on the underside of the leaf and they hatch into the larva you are seeing and end up as a ladybug-like bug with bigger spots. These guys will wipe out your bean crop and will move over to the next row and get your squash and cucumbers next. I am reluctant to spray but end up sometimes spending more time squashing these buggers than picking beans. Good luck