A couple of things give this one away as a bug, not a beetle. First, the mouthparts (not visible in this shot) are a long sucking beak, not a pair of mandibles. Second, the hard covering over the abdomen is in one piece (it is an enlarged scutellum, part of the thorax), whereas in a beetle the covering over the abdomen is formed by the two elytra (hardened, modified front wings) which meet in a straight line down the middle.