[1] : The Collaborative International Dictionary of English v.0.48

bacon \ba"con\, n. of. bacon, fr. ohg. bacho, bahho, flitch of
   bacon, ham; akin to e. back. cf. back the back side.
   the back and sides of a pig salted and smoked; formerly, the
   flesh of a pig salted or fresh.
   1913 webster

   bacon beetle zool., a beetle dermestes lardarius
      which, especially in the larval state, feeds upon bacon,
      woolens, furs, etc. see dermestes.

   to save one's bacon, to save one's self or property from
      harm or loss. colloq.
      1913 webster bacon
see also:
bacon beetle dermestes lardarius dermestes to save one's bacon 

[2] : The Collaborative International Dictionary of English v.0.48

dermestes \dermes"tes\, n. nl., from gr. dermhsth`s; de`rma
   skin + root of ? to eat. zool.
   a genus of coleopterous insects, the larvae of which feed
   animal substances. they are very destructive to dries meats,
   skins, woolens, and furs. the most common species is
   dermestes lardarius, known as the bacon beetle.
   1913 webster
see also:
dermestes lardarius bacon beetle 

Dermestes >> D Words
Dermestes, definition of term: Dermestes
dermestes_pag1.html