"her lovely death's head"

Deaths-Head Hawkmoth
Creative Commons Attribution Share AlikeDeaths-Head Hawkmoth - Credit: Trevor Hartsell
A death's head is traditionally either a real or depicted human skull, symbolising death and mortality.  It can also be used to denote melancholy.  As well as a visual device, it is also used in literature.  In Shakespeare's 'Henry IV, Part 2', Falstaff says imploringly to Doll, "Do not speak like a death's head; do not bid me remember mine end" after she has nagged him to take better care of himself.  The term also lends itself to the Death's-head Hawkmoth, due to the strange skull-like shape on its thorax.