dragonfly vs vermin

dragonfly

noun
  • An insect of the suborder Epiprocta or, more strictly, the infraorder Anisoptera, having four long transparent wings held perpendicular to a long body when perched. 

vermin

noun
  • Any one of various common types of small insects or animals which cause harm and annoyance. 

  • Animals that prey on game, such as foxes or weasels. 

  • Obnoxious, or mean and offensive person or people. 

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