Source : Webster's Revised Unabridged Dictionary (1913)

Death's-head \Death's"-head`\, n.
   A naked human skull as the emblem of death; the head of the
   conventional personification of death.

         I had rather be married to a death's-head with a bone
         in his mouth.                            --Shak.

   {Death's-head moth} (Zo["o]l.), a very large European moth
      ({Acherontia atropos}), so called from a figure resembling
      a human skull on the back of the thorax; -- called also
      {death's-head sphinx}.

Source : WordNet®

death's-head moth
     n : European hawkmoth with markings on the back resembling a
         human skull [syn: {Acherontia atropos}]