Longtime stage personality of Australian comedian Barry Humphries, Dame Edna Everage evokes an older, more genteel age of female impersonation. With her trademark cat-eye glasses, lavender coiffure, and gently acerbic observations on aging, celebrity, and living the good life, Edna has the air of the Queen Mother about her — and no doubt she is just as adored by her public. Billed as her "last first" tour, the grand dowager's latest show at the Post Street Theater is sure to pack in plenty of her familiar schticks ("Hello, possums!") as well as some new perspective afforded by her 40-plus years in show business.