combine harvester vs harvestman

combine harvester

noun
  • A combine, a farming machine that harvests, threshes, and cleans grain plants. 

harvestman

noun
  • A field-worker who works to gather in the harvest. 

  • An order of terrestrial, non-venomous arachnids with often very long legs: Opiliones. 

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