What -- no pumpkin? Whoever heard of Cinderella without a pumpkin?

The Washington Opera's new production, opening in the Terrace Theater tonight, is undoubtedly "Cinderella," even if the name sounds odd with an Italian accent -- "Cenerentola." It has the basic ingredient: A beautiful, modest young heroine who is abused by her mean, ugly stepsisters goes to a ball and ends up marrying a prince.

That's the plot of the simple, wonder-filled story that was published by Charles Perrault (along with "Sleeping Beauty," "Bluebeard," "Little Red Riding Hood" and others) in 1697. When Rossini and his librettist, Jacopo Ferretti, picked this story in 1816 (at the last minute, under a tight deadline, as was his custom), they chose a proven winner with established audience appeal -- there had already been several theatrical or operatic versions. And they kept the basic plot, even if they did give Prince Charming the undistinguished name of Don Ramiro. (He is nameless -- called simply le fils du roi or le prince -- in Perrault's text.)

But they made a few changes -- operas are like movies that way; people who read the book (not to mention people who wrote it) are likely to wonder what happened in the transition from one medium to the other. It's less of a problem in "The Turn of the Screw," which The Washington Opera will open in a new production tomorrow night. Benjamin Britten and his librettist, Myfanwy Piper, didn't so much change the Henry James story as simplify and condense it. The opera preserves the central characters of the novel. Above all, it catches its essence: the ambiguously sexual overtones; the sense of eerie, supernatural presences, of children in danger and of evil lurking in the dark corners of an isolated Victorian country house. A lot of detail is lost, and the author's intricate style is mostly boiled down to simple declarative sentences. But the impact of the work is heightened by its condensation, the stage spectacle and lighting -- above all, by the music.

With Rossini and "Cinderella," the changes are much more drastic. Not only the pumpkin is jettisoned, but all the magic as well: The mice who were so important in Walt Disney's version; the lizards who were promoted to footmen; the transformation of rags to a designer-original party gown at the touch of a magic wand. There is no glass slipper, no fairy godmother . . . not even a wicked stepmother. Talk about simplification.

Rossini was not the first to make changes in the story. It has been traced back as far as 9th-century China and exists in more than 500 variations -- including a very bloody one preserved by the brothers Grimm in which the wicked stepsisters mutilate their feet and bleed all over the crucial slipper (a gold one in this version), then have their eyes pecked out by birds.

But Rossini's changes were probably the most drastic -- partly because he had no interest in the supernatural and partly because the opera house of Rome, where "Cenerentola" had its premiere, was not equipped for spectacular stage effects. Jules Massenet's "Cendrillon," composed for Paris where scenic wizardry was an old tradition, keeps a lot of the supernatural element and adds a ballet and chorus of fairies, foreshadowing and overshadowing Disney's chorus of mice.

The limitations of the Roman opera house also account for the loss of the glass slipper. This is not a particularly supernatural element, though it would have to be very unusual glass to survive a dance on the stone floor of a medieval castle. The problem was that actresses were forbidden to display their legs in Rome, which was then governed by the pope. So in Rossini's version the glass slipper becomes a bracelet. Later, a Paris critic suggested that this change was made because Giorgi-Righetti, who sang the premiere, had big feet and ugly legs. She denied this in an indignant letter to the editor. Incidentally, the slippers were not originally made of glass (verre in French), but of vair, a white and gray fur that was considered very elegant in the Middle Ages. Oral tradition has a way of transforming the commonplace into the strange and wonderful.

If there are no pumpkins, no mice, no fairy godmother or wicked stepmother, what will the sold-out audience be seeing and hearing in the Terrace tonight? Musically, "Cenerentola" is a standard Italian buffo opera, enriched by Rossini's melodic genius and his willingness to demand exceptional vocal feats of his stars. The title role, in particular, requires an alto or mezzo soprano with strong dramatic presence, a wide variety of vocal shadings and an upper register of unusual power and agility. The father and two sisters need considerable comic talent as well as good voices.

The fact that the title role is for a mezzo -- and not a mezzo of ordinary powers -- probably helps to explain why it was eclipsed for so long. Not long after this opera made its debut, operatic audiences began to be infatuated with sopranos (particularly coloraturas) rather than mezzos -- a form of madness that remains strong even today. Rossini, always the complete professional, readily adapted to this new taste in his later operas, and "Cenerentola" slipped out of the repertoire almost completely for a century. It was revived in the 1930s as a vehicle for the spectacular Spanish mezzo Conchita Supervia. Among Rossini's operas, it is now second in popularity only to "The Barber of Seville."

Dramatically, "Cenerentola" is funnier and faster-moving than most buffo operas. And its theme is off the beaten path for that genre, which usually deals with the lecherous urges of old men and misunderstandings between young lovers. By sacrificing the supernatural razzle-dazzle, Rossini puts a tight focus on two key themes that are usually eclipsed by the fairy godmother's gee-whiz contributions: social climbing and sibling rivalry. His comments on these permanent human concerns -- embodied in the roles of Don Magnifico (Cenerentola's fatuous father) and the two sisters Clorinda and Tisbe -- should interest adult audiences more than recipes for making a coach out of a pumpkin.