Bug. Macrophotograph of a bug, Punaise pentato- mide, a member of the Brachynema family. Bugs are insects which have a wide range of body forms and behaviour, but they generally have sucking mouthparts. Many bugs have an unpleasant odour which they secrete from special glands to deter predators. P. pentatomide combines this defense with camouflage, its predominantly green body blending in with meadow grasses.