coprophagan vs scarab beetle

coprophagan

noun
  • Any of a number of beetles that feeds on dung. 

scarab beetle

noun
  • Any of very many beetles, of the family Scarabaeidae, especially Scarabaeus sacer regarded as sacred by the ancient Egyptians 

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