E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
The Chinese men were made to shave their heads and wear a queue or tail by the Manchu Tartars, who, in the seventeenth century, subdued the country, and compelled the men to adopt the Manchu dress. The women were allowed to compress their feet as before, although the custom is not adopted by the Tartars.
Anglicus a tergo caudam gerit probably refers to the pigtails once worn.