Which Tolkien work contains the story of the dragon Chrysophylax Dives?

The dragon Chrysophylax Dives appears in Tolkien’s story Farmer Giles of Ham.

Farmer Giles of Ham is a humorous mock-medieval tale about Ægidius Ahenobarbus Julius Agricola de Hammo, usually called Farmer Giles. After he accidentally drives away a giant, the king recognizes him as a local hero. Giles is then drawn into dealing with Chrysophylax Dives, a proud and troublesome dragon.

The story was published in 1949, several years before The Lord of the Rings. Unlike Tolkien’s major Middle-earth narratives, it is a compact comic fable set in a pseudo-English landscape, with playful names and a satirical approach to heroic conventions.

Chrysophylax Dives is sometimes confused with Smaug because both are Tolkien dragons who guard treasure and bargain with people. Smaug belongs to The Hobbit, while Chrysophylax belongs to Farmer Giles of Ham. Their stories have different tones and settings.