geometrid vs spanworm

geometrid

noun
  • A larva of such moth, which when walking alternate legs and prolegs, giving the appearance of measuring 

  • Any of the family Geometridae of moths 

adj
  • Relating to such moths 

spanworm

noun
  • A measuring worm or inchworm (Lepidoptera, Geometridae) 

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