Siphonaptera members, commonly known as fleas, are small wingless insects that feed on the blood of mammals and birds. They are characterized by their laterally compressed bodies, which enable them to move quickly and easily through fur or feathers. Fleas are known for their ability to jump long distances, and they can transmit diseases such as plague and typhus. Fleas are also a common nuisance to humans and pets, as they can cause skin irritation and discomfort.