The Collaborative International Dictionary of English v.0.48:

Ant-lion \Ant"-li`on\, n. (Zool.)
   A neuropterous insect, the larva of which makes in the sand a
   pitfall to capture ants, etc. The common American species is
   Myrmeleon obsoletus, the European is Myrmeleon
   formicarius.
   [1913 Webster] Antoeci

WordNet (r) 3.0 (2006):

antlion
    n 1: the larva of any of several insects [syn: doodlebug, ant
         lion, antlion]
    2: winged insect resembling a dragonfly; the larvae (doodlebugs)
       dig conical pits where they wait to catch e.g. ants [syn:
       ant lion, antlion, antlion fly]