The Collaborative International Dictionary of English v.0.48:

Aphis lion \A"phis li"on\ (Zool.)
   The larva of the lacewinged flies (Chrysopa), which feeds
   voraciously upon aphids. The name is also applied to the
   larv[ae] of the ladybugs (Coccinella).
   [1913 Webster]

WordNet (r) 3.0 (2006):

aphis lion
    n 1: carnivorous larva of lacewing flies [syn: aphid lion,
         aphis lion]