An adult bed bug is about 1/5″ long and 1/8″ wide. Its reddish-brown body is greatly flattened and oval-shaped. A bed bug has piercing-sucking mouthparts which enable it to pierce the skin and suck blood from its host. Its Latin name is Cimex lectularius.
Bed bugs are generally active only at night because of their dislike for sunlight, with a peak feeding period about an hour before sunrise. Attracted by warmth and the presence of carbon dioxide, the bug pierces the skin of its host with two hollow tubes. With one tube it injects its saliva, which contains anticoagulants and anesthetics, while with the other it withdraws the blood of its host. After feeding for about five minutes, the bug returns to its hiding place. The bites cannot usually be felt until some minutes or hours later, as a dermatological reaction to the injected agents, and the first indication of a bite usually comes from the desire to scratch the bite site.