An insect belonging to the genus Pulex, of the order
   Aphaniptera. Fleas are destitute of wings, but have the power of
   leaping energetically. The bite is poisonous to most persons. The human
   flea (Pulex irritans), abundant in Europe, is rare in America, where
   the dog flea (P. canis) takes its place. See Aphaniptera, and Dog flea.
   See Illustration in Appendix.