cockroach vs harvestman

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. 

harvestman

noun
  • An order of terrestrial, non-venomous arachnids with often very long legs: Opiliones. 

  • A field-worker who works to gather in the harvest. 

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