dipteran vs insect

dipteran

noun
  • An insect of the large order Diptera; a fly. 

adj
  • Relating to or denoting dipterans. 

insect

noun
  • Any small arthropod similar to an insect, including spiders, centipedes, millipedes, etc. 

  • An arthropod (in the Insecta class) characterized by six legs, up to four wings, and a chitinous exoskeleton. 

  • A contemptible or powerless person. 

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