Properly done, Giacomo Puccini's "La Rondine" ("The Swallow") is a winsome little piece, but it needs all the help it can get. In the Summer Opera Theatre's production, which opened Wednesday night at the Hartke Theatre, it gets almost all the help it needs.

In this work, Puccini tried a once-in-a-lifetime experiment: an operetta in the Viennese tradition. Puccini could toss off a waltz as well as any composer, as he demonstrates in this score, but he lacked the cynicism that lies at the heart of Viennese operetta and he was not ready to have his music share the stage with spoken dialogue. What he wanted to write, he said, was something "like 'Rosenkavalier,' but more amusing and more organic." He didn't quite make it (nobody could), but his effort was valiant and worthwhile.

"La Rondine" is like "Rosenkavalier" in a few spots; more often, it is like "La Traviata" or "La Bohe me," and its plot faintly echoes bits of "Die Fledermaus." But overall it is not quite like anything else in opera. That may be its problem. It received mixed reactions in its early productions and drifted slowly outside the fringes of the basic repertoire, where it has stayed ever since. Unjustly, perhaps; it never quite equals the greatest moments of "Tosca," "Bohe me" and "Madame Butterfly," but it often comes close and its overall standards of craftsmanship are vintage Puccini.

Only standing-room tickets are left for the repeat performances tonight and Sunday. But connoisseurs might be willing to stand up for what the work offers: a glimpse of a thorough pro at work on material that inspired his technique rather than his libido. One suspects that the real problem of "La Rondine," down where Puccini's deepest and most irrational inspirations lurked, was that it lacked a fragile heroine who died at the end. Magda (the "swallow" in the title) is quite able to take care of herself. She lures the tenor into a love affair, sensibly sees its limitations and leaves him, at the end, on the verge of nervous collapse. This was not really congenial stuff for the composer who loved Mimi and Butterfly but killed them anyway amid unbelievably lush music.

The lushness is there anyway, notably in the second act's love duet, in which a crowd of blase' Parisians recognizes true love being born and showers the lovers with flowers. Puccini showers them with musical flowers as well, and he catches the tone of anguish in the duet of renunciation in the next act. Elsewhere, he is witty, brilliant and always highly competent; all that is missing is the touch of ecstasy, the final spark of overpowering, irrational inspiration: the magic five or 10 minutes for which hard-core fans of romantic opera will spend hours patiently waiting.

"La Rondine's" strong points are served imaginatively and with fine technical skill in this production. John Lehmeyer's stage direction, always a major attraction in this company's productions, is dazzling this time. He is particularly impressive in Act 2, where he manages to achieve lavish effects with modest means, largely through his use of the chorus, its gestures, costumes and props. His orchestration of choral entrances and exits as the scene moves back and forth between intimacy and a bustling crowd scene is a classic exemplar of a highly specialized art.

Recognizing the essential insubstantiality of the story, he has framed the production so that Act 2 and most of Act 3 are presented as a dream of the heroine. This gives the text a neat, added twist, elaborating on the overtones of the Act 1 tenor aria about "Doretta's beautiful dream." Only careful students of the libretto are likely to appreciate such finesse, but it does add a new dimension and does not conflict with the received text.

The orchestra, expertly conducted by Benton Hess, sounded good, and the singing was generally of a high standard. In Act 1, the show was decisively stolen by soprano Jody Rapport and tenor Howard Carr, who provided the most substantial part of the evening's comic element and a lot of its best singing. Their performance all evening was impressive in its own right, but the Act 1 victory was won almost without competition; lead tenor Philip Bologna does not have much to do until Act 2 and lead soprano Linda Green took a long while getting her voice fully under control and properly projected -- a pity, since some of her best music comes early in the opera.

When his time came, in Act 2, Bologna sang superbly and acted acceptably. His voice has acquired considerable nuance in the last year or so, and his technique is notably improved. Alan Baker was perfectly cast in the closest thing this opera has to a villain's role; the supporting singers (who are given some good material) generally performed well, and the chorus was a pure delight.