Fleas belong to the order Siphonaptera, this name comes from “Siphon”(sucking mouth-part), “a”(without), and “ptera”(wings), referring to their wingless and bloodsucking characteristics. Cat fleas (Ctenocephalides felis) are frequently encountered in homes and are common pests on domestic cats and dogs. Adult fleas are very small insects (up to 1/8 inch), so it is difficult to see a number of the characteristics used to describe them.
These reddish brown to black, wingless insects are compressed from side to side so that they look like they are walking “on edge.” They have piercing-sucking mouthparts through which they obtain blood meals from their hosts. Flea larvae are tiny (up to 3/16 inch long), hairy, and wormlike with a distinct, brownish head, but no eyes or legs.