A fine cast, which included a performer making his Metropolitan Opera debut, made ``Abduction from the Seraglio'' a musical and visual treat. James Levine conducted the Mozart comedy with dash on Monday night. Lars Magnusson, a principal lyric tenor with the Royal Opera in Stockholm, was making his U.S. opera debut as Pedrillo, servant of Belmonte, a Spanish nobleman. It's the role he sang for his 1987 debut at Covent Garden and will sing for his San Francisco Opera debut next season. He has an unusual light tenor voice. It doesn't get heavy but it does have character. It's as though it has been given a light layer of wood-grained baritone tonal quality, the way colored varnish might be brushed onto a light wood. It sounds right for David in ``Die Meistersinger,'' which was Magnusson's Paris Opera debut role. Stanford Olsen of Salt Lake City provided a good tenor contrast as Belmonte. Olsen sounded serious, his voice focused and seemingly ready to sing oratorio. Mariella Devia of Imperia, Italy, sang Konstanze, the young woman who has been captured by pirates and sold to the Pasha for his harem. Her maid, Blondchen, and Pedrillo are captives in the Pasha's residence _ seraglio _ with her. Miss Devia's singing was like a string of pearls, her tone sweet, each note carefully rounded and clear. Both she and Barbara Kilduff as Blonchen had coloratura passages and both sang them beautifully. Miss Kilduff's acting was more understated and less relentlessly pert than some who sing Blonchen. But Magnusson was more nimble than most who sing Pedrillo, so the balance of that pair of sweethearts was maintained. Bass Kurt Moll of Buir, Germany, was Osmin, the Pasha's overseer. He was the only one in the cast who sang his part when this production was introduced in 1979. Moll has a voice of depth and richness and he has added some effective bits of comedy to a portrayal that already was very funny. Nico Castel took the speaking part of the Pasha. He creates the happy ending after Osmin discovers the abduction attempt by wandering around and sticking his arm through the plotters' ladder.