Bedbug. Coloured scanning electron micrograph (SEM) of a bedbug (Cimex sp.). Adult bedbugs' bodies are flattened, oval, and wingless, with microscopic hairs that give them a banded appearance. They feed on the blood of warm-blood animals, including humans. Bedbugs are generally only active at night, hiding in crevices in walls and furniture and in bedding during the day. Although they do not transmit disease, their saliva can cause itchy swellings on the skin. Magnification: x15 when printed 10 centimetres wide.