cockroach vs louse

cockroach

noun
  • A black or brown straight-winged insect of the order Blattodea. 

  • A Tutsi. 

  • A person from New South Wales. 

  • A person or a member of a group of people regarded as undesirable and rapidly procreating. 

louse

noun
  • A small parasitic wingless insect of the order Psocodea. 

verb
  • To remove lice from; to delouse. 

How often have the words cockroach and louse occurred in a corpus of books? (source: Google Ngram Viewer )