harvestman vs violin spider

harvestman

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

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

violin spider

noun
  • Any recluse spider (Loxosceles and Sicarius spp.), known for the violin-shaped marking on its thorax. 

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