Definition of "bacchante"

“… There was a man who always painted marble seats and another who did nothing but sheep. So a fellow I knew determined only to paint backs. Men's backs, women's backs, girls' backs and boys backs. […] his best known bacchante was described by a critic as all back and no ante, but his backs became famous. […] ”

1936, Herbert Adams, chapter 2, in A Word of Six Letters‎