Source : Webster's Revised Unabridged Dictionary (1913)

Cockchafer \Cock"chaf`er\, n. [See {Chafer} the beetle.]
   (Zo["o]l.)
   A beetle of the genus {Melolontha} (esp. {M. vulgaris}) and
   allied genera; -- called also {May bug}, {chafer}, or
   {dorbeetle}.

Source : WordNet®

cockchafer
     n : any of various large European beetles destructive to
         vegetation as both larvae and adult [syn: {May bug}, {May
         beetle}, {Melolontha melolontha}]