deer ked vs deerfly

deer ked

noun
  • A Eurasian species of louse fly in the family Hippoboscidae, Lipoptena cervi, that are parasites of elk, deer and other bovine animals, sucking blood and laying eggs in the fur of the host animals. 

deerfly

noun
  • Any of various species of fly which feed on deer, principally in genus Chrysops. 

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