dragonfly vs praying mantis

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. 

praying mantis

noun
  • Any of various predatory, cannibalistic insects of the order Mantodea that have a prayer-like stance. 

  • A woman who preys on men (from the idea that female praying mantises eat males after sex). 

  • A mantid of the species Mantis religiosa. 

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