Having earned a devoted following for her rollicking antics and unshakable poise, Miss Julia's eighth outing begins with an unfortunate discovery. Her cherished engagement ring-an exact replica of Princess Di's-turns up missing after a party, making her the latest target of a Florida- based gang who, according to Sergeant Coleman Bates, has been denuding Dixie of its jewelry. Incensed, Miss Julia packs Little Lloyd into the car and heads south to claim what is rightfully hers-and to show the feds that there's more than one way to do reconnaissance: selling the Good Book