Mariella Devia

The closing weeks of the Metropolitan Opera season offered to New York audiences the Constanze of Mariella Devia, a soprano heard earlier this season as a spectacular Gilda. John Dexter's pallid production of Mozart's ''The Abduction From the Seraglio'' did not allow Miss Devia the fullest chance to show off her acting gifts. Nor is Mozart's heroine going to be her greatest role.

Nonetheless, she is the best Constanze the house has had since the production was new. The voice is of an uncommonly rich timbre, and has a tremendous range. Her coloratura is clean, spitfire when needed, yet she can float and spin phrases seamlessly.

The Gilda, a concert performance of ''Lakme'' last season, and this ''Abduction,'' convince me that Miss Devia is the finest young coloratura around today, the only one in her age group ready for the career upon which she is embarking. That an Italian could be so accomplished in a German opera is just one of her many striking accomplishments.