An insect of the order Siphonaptera, marked by lateral compression, sucking mouthparts, extraordinary jumping powers, and ectoparasitic adult life in the hair and feathers of warm-blooded animals. Important fleas include Ctenocephalides felis (cat flea), or C. canis (dog flea), Pulex irritans (human flea), Tunga penetrans (chigger, chigoe, or sand flea), Echidnophaga gallinacea (sticktight flea), Xenopsylla (rat flea), and Ceratophyllus.Copepoda.