Eugene A. Rau (1848-1932), a Bethlehem, Pennsylvania pharmacist, is best known for his development of the pharmaceutical and botanical sciences. This collection includes sixteen pages of notes (numbered 1-16) followed by twenty-seven illustrations of lepidoptera (numbered 17-44). The lepidoptera are done in pencil and watercolor and in most cases include notes. Judging from Rau's notes, the drawings are of lepidoptera from the Academy's collections during Rau's time.