Skip to main content Skip to Search Box

Definition: flea from Philip's Encyclopedia

Any of 1,000 species of wingless, leaping insects found worldwide. They are external parasites on warm-blooded animals. In moving from one host to another, they can carry disease. Length: to 1cm (0.4in). Order Siphonaptera.


Summary Article: flea
from The Columbia Encyclopedia

common name for any of the small, wingless insects of the order Siphonaptera. The adults of both sexes eat only blood and are all external parasites of mammals and birds. Fleas have hard bodies flattened from side to side and piercing and sucking mouthparts. Their legs are powerful and adapted for fast movement and jumping, enabling them to find new hosts as well as to escape quickly the attempts of the hosts to remove them. The adults can survive away from a host for several weeks without eating. Flea eggs are usually laid in dirt or in the nest of the host; the larvae feed on organic material and the feces of adult fleas. Metamorphosis is complete; the larvae spin silken cocoons when ready to pupate. Many species are not specific to a particular host species, and cat and dog fleas, as well as the human flea of the warmer parts of Europe and Asia, attack humans. Certain rat fleas transmit typhus and bubonic plague to humans, and another species transmits tularemia from rabbits. Fleas also transmit several species of tapeworms that sometimes infest humans. The chigoe is a flea. Water fleas and beach fleas are crustaceans and not closely related to the insects. Fleas are classified in the phylum Arthropoda, class Insecta, order Siphonaptera.

The Columbia Encyclopedia, © Columbia University Press 2018

Related Articles


Full text Article Cat Fleas
Encyclopedia of Insects

Fleas are small (2 mm), dark, reddish brown, wingless, bloodsucking insects. Their bodies are laterally compressed (i.e., flattened side to side)...

Full text Article Siphonaptera
Encyclopedia of Insects

(Fleas) The Siphonaptera are laterally compressed, wingless, holometabolous insects. The order contains approximately 2575 species. All species...

Full text Article Bubonic Plague
Encyclopedia of Insects

Bubonic plague, a devastating bacterial disease most commonly transmitted by fleas, has produced profound changes in human societies throughout...

See more from Credo