Barna Ostertag, 91, theatrical agent and actress, died Aug. 16 in New York of natural causes.Born in Piqua, Ohio, Ostertag received her early training as an actress at the Goodman Repertory Theater in Chicago. She later moved to New York. During World War II, she worked for the Red Cross in the South Pacific. She was a lifetime member of Actors’ Equity and the National Assn. of Talent Representatives. No immediate survivors.