Cite

Feather of peacock, about two-thirds of natural size, carefully drawn by Mr. Ford. The transparent zone is represented by the outermost white zone, confined to the upper end of the disc

MLA

Feather of Peacock, about Two-Thirds of Natural Size, Carefully Drawn by Mr. Ford. The Transparent Zone Is Represented by the Outermost White Zone, Confined to the Upper End of the Disc. 0AD. https://collections.library.yale.edu/catalog/2039920.

APA, 6th edition

Feather of peacock, about two-thirds of natural size, carefully drawn by Mr. Ford. The transparent zone is represented by the outermost white zone, confined to the upper end of the disc. (0 C.E.). [Drawings, Engravings, Illustrations]. https://collections.library.yale.edu/catalog/2039920.