Bed bug. Coloured Scanning Electron Micrograph (SEM) of a bed bug, Cimex lectularius. The head of the insect (lower centre) has a pair of compound eyes with small facets, two antennae, and piercing mouthparts. It has a broad, flat, Chestnut body devoid of wings, and six walking legs. A regular diet of blood is necessary for bed bugs to reach maturity, and after a blood meal the body becomes quite swollen. The bite of a bed bug produces swellings on the skin. These swellings are usually only detected after the bed bug has retreated to its day-time resting place such as on mattresses, floors, or in tears in furniture. Magnification: x11.5 at 6x4.5cm size. x50 at 8x10 inch print size x8 at 35mm size.