cockchafer vs dung beetle

cockchafer

noun
  • Any of various other similar beetles, such as of the genera Acrossidius, Cyphochilus, Rhopaea, etc. 

  • Any of the large European beetles from the genus Melolontha that are destructive to vegetation. 

dung beetle

noun
  • Any of the true dung beetles of subfamily Scarabaeinae. 

  • Any of the beetle of the family Scarabaeidae (scarab beetles), especially of the subfamilies Scarabaeinae and Aphodiinae, noted for rolling dung into balls for use as food or as brooding chambers. 

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