honeydew melon vs rockmelon

honeydew melon

noun
  • A melon from the Cucumis melo Inodorus cultivar group, with sweet, light green or white flesh and a smooth greenish-white or yellow rind. 

rockmelon

noun
  • A type of melon, Cucumis melo var. reticulatus, with sweet orange flesh and a rough skin resembling netting. 

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