gnat vs mosquito

gnat

noun
  • An annoying person. 

  • Any small insect of the order Diptera, specifically within the suborder Nematocera. 

mosquito

verb
  • To fly close to the ground, seemingly without a course. 

noun
  • A small flying insect of the family Culicidae, the females of which bite humans and animals and suck blood, leaving an itching bump on the skin, and sometimes carrying diseases like malaria and yellow fever. 

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