harvest mite vs sand flea

harvest mite

noun
  • Any of various mites of the genus Trombicula that inhabit forests and grasslands and which, in their larval stage, attach to various animals including humans and feed on skin, often causing itching. 

sand flea

noun
  • Any of various small crustaceans of the family Talitridae (order Amphipoda), that are found on beaches and jump like a flea. 

  • A small tropical flea, Tunga penetrans; a chigoe (family: Tungidae, order: Siphonaptera). 

How often have the words harvest mite and sand flea occurred in a corpus of books? (source: Google Ngram Viewer )