dragonfly vs fruit fly

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. 

fruit fly

noun
  • any insect of the Tephritidae family, whose larvae damage plant tissue. 

  • any insect of the Drosophilidae family, whose larvae feed on ripening fruit, especially the species Drosophila melanogaster that is used in genetic research. 

  • A woman who enjoys the company of homosexual men; a "fag hag". 

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