"her lovely death's head"
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.