What is "death's-head sphinx"

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.