The Collaborative International Dictionary of English v.0.48:

Pulex \Pu"lex\, n. [L., a flea.] (Zool.)
   A genus of parasitic insects including the fleas. See Flea.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Pulex
    n 1: type genus of the Pulicidae [syn: Pulex, genus Pulex]