All bed bugs are in the family Cimicidae. The common species can be found in Hong Kong and Taiwan is called Cimex lectularius. Adult bed bugs are oval, wingless, about 6mm long and 3mm wide, and rusty red or mahogany in color. Their bodies are flattened, they have a four segmented antennae, and a three segmented mouthparts. The immatures appear identical to the adults except for their smaller size, and a lighter or yellowish white color.