Beverly Sils is saying goodbye to Washington again, but no cause for retirement was betrayed in her performance. With the New York City Opera's "Il Barbiere di Siviglia" by Rossini at Wolf Trap last night, the diva-turned-impresaria gave a thrilling and humorous performance which left the audience shouting with joy.

In her portrayal of Rosina there was none of the depth and understanding that she has brought to so many roles. Instead, she gave her famous performance as Bubbles having fun with her loving public; and fun there was. Gone were the pitch problems and other maladies that have marked some of her recent work. There was her amazingly accurate coloratura, her breath-taking speed, and surely what is even today one of the sexiest, most agile vocal instruments on any stage.

"Una Voce Poco Fa" had been heard more elegantly but seldom more beautifully. For the famous lesson scene, she dropped Rossini's "Contro Un Cor . . ." in favor of the coloratura extravaganza "Ah Vous Dirais Je, Maman," which again stopped the show. Sills once said that she wished that she could be paid by the note instead of by the performance when singing a Rossini score. She would have been a very rich woman after all the incredible ornamentations heard in this aria.

Sarah Cladwell led the opera with a rare combination of instinct and intelligence, knowing exactly when to keep her singers in check, and when to let the music simply breathe. She helped a slow Count and a fast Figaro and she obtained glorious sounds out of her strings.

Equally glorious was the Don Basilio of Robert Hale, if a bit overdirected. His "La Calunnia" aria was a lesson in bel canto. As Bartolo, Spiro Malas was a perfect vocal and comedic match for Sills, his glory being less only because that is the fate of a bass in opera. Bartolo's aria "A un dottor della mia sorte" left no vocal or dramatic nuance unexplored.

Henry Price was not at his best as the Count, and his dashing good looks were hurt by dreadful makeup in the first act. Still his Count Almaviva improved after "Ecco ridente in cielo" and his light tenor voice shimmered in the duet with Figaro "All'idea di quel metallo." His short duet with Bartolo, "Pace e gioia . . ." was a musical high point of the evening. Richard Fredericks' Figaro, on the other hand, sounded positively pinched in the famous "Largo al factotum" and elsewhere, with the Rossinian patter proving too fast for his powers.

The staging was less zany than Caldwell's own for Boston, and it worked for the most part. There was an unnecessarily silly slow motion finale to Act II (Act I in the original -- this production is done in three acts) which among other things made the singers inaudible. The NYCO chorus took the opening words "piano pianissimo" much too literally throughout the night. And the modest production invoked the ghosts of productions past more than once, especially in the costumes.

But why quibble? It was fun, and it was Sills. The evening belonged to the diva, and her love and her song will be missed.