The Collaborative International Dictionary of English v.0.48:

lanternfly \lanternfly\, lantern fly \lantern fly\n. (Zool.)
   any one of several species of large, handsome, brightly
   marked, tropical hemipterous insects of the genera
   Laternaria, Fulgora, and allies, of the family
   Fulgorid[ae]. The largest species is Laternaria
   phosphorea of Brazil. The head has a snoutlike process in
   some species which was formerly thought to emit a
   phosphorescent light.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

lantern-fly
    n 1: large brightly marked tropical insect with a process like a
         snout that was formerly thought to emit light [syn:
         lantern fly, lantern-fly]