According to S. Nott, Chinese Jade Throughout the Ages, New York, 1937, p. 85, the popular theme of a cat and butterflies was popularized by the Emperor Ming Huang. The emperor was supposedly strolling in the palace grounds when a cat leapt out of the bushes and crossed his path, chasing a butterfly. This incident so impressed him that he recorded it in poetry. Since then the motif of the cat chasing butterflies has become a rebus expressing the wish that one will live until seventy or eighty. The word for cat and for octogenarian, mao, are homonyms and butterflies symbolize the number seventy.