The Collaborative International Dictionary of English v.0.48:
Death's-head \Death's"-head`\, n.
A naked human skull as the emblem of death; the head of the
conventional personification of death.
[1913 Webster]
I had rather be married to a death's-head with a bone
in his mouth. --Shak.
[1913 Webster]
Death's-head moth (Zool.), 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.
[1913 Webster]