A genus of fleas belonging to the order Siphonaptera. Common species are C. canis and C. felis, the dog flea and cat flea, respectively. The adults feed on their hosts, whereas the larvae live on dried blood and feces of adult fleas. Adults may attack humans and other animals. They are intermediate hosts of the dog tapeworm, Dipylidium caninum, and may transmit other helminth and protozoan infections.