Madame Flora, the spiritualist heroine in Gian Carlo Menotti’s The Medium, cynically fakes seances for a living, but one day something happens during a session that she can’t quite explain–she hears voices and feels cold hands grasping at her throat, ghostly torment that continues until the shocking climax. This one-act, written in 1946, when Menotti had just begun blending Broadway with opera, owes a debt to his favorite composers, Verdi and Puccini. While characterization in The Medium often borders on mere caricature, a perennial Menotti flaw, the piece is musically engaging and full of deft theatrical touches. This revival is sure to benefit from Met diva Mignon Dunn in the title role; Chicago-based soprano Patrice Michaels Bedi will make her Chicago Opera Theater debut as Flora’s daughter Monica. The program opens with Dominick Argento’s satiric A Waterbird Talk, in which a Henry Higgins-like professor lectures on the habits of waterfowl, but it quickly becomes apparent that he’s talking about the henpecking in his own domicile. Baritone Robert Orth sings the part of the ironist. Kurt Klippstatter, head of the Illinois Opera Theatre, conducts, and Richard Peerlman, a former apprentice of Menotti’s, is in charge of staging. Tonight, 8 PM, and Sunday, 3 PM, Lund Auditorium, 3 PM, 7900 W. Division, River Forest; 663-0048.