aphid vs caterpillar

aphid

noun
  • Sapsucking pest insect of the superfamily Aphidoidea; an aphidian. 

caterpillar

noun
  • The larva of a butterfly or moth; leafworm 

  • A vehicle with a caterpillar track; a crawler 

  • A set of subtrees of a tree 

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