The Stuttgart Ballet concluded its Washington season this weekend with a flourish of fine performances: a final production of John Neumeier's evening-length "Lady of the Camellias" on Saturday's matinee; that evening a mixed program of shorter, nonnarrative works ("Concerto for Flute and Harp," "Return to the Strange Land," and "Initials R.B.M.E.") and, on Sunday, two performances of "Eugene Onegin," substituted by reason of popularity for additional scheduled performances of "Camellias."

Everybody loves an unhappy love story, and the Stuttgart specializes in unhappy love stories - which may be why so many people love the Stuttgart. The company's famous narrative ballets are, in their own ways, as formulaic as the old-time classics they update. Both "Onegin" and "Lady of the Camellias" are built around a series of pas de deux, each centered at a different phase in the developing (or languishing) romance with elaborated social dances for the corps ebbing and surging smoothly, and more-or-less naturally, around these dramatic denouements.

Onegin remains the classical, and most successful example of the type. My quarrel with "Camellias" is that there's either too little choreography (as in Marguerite's interview with Armand's father where one somehow exspects the dancers to break into song) or else much too much choreography with a capital "C": too many swooning overhead lifts or passages with the women arched over backward and men's noses buried between their bosoms in what, by the end, becomes almost a parody of lechery.

In "Camellias," and in the three abstract ballets performed Saturday evening, the Stuttgart has a tendency to handle women like mermaids who have to be carried because they can't walk.

Paradoxically, this tendency, carried to an extreme in Jiri Kylian's "Return to the Strange Land," was effective perhaps because the ballet consists of little else and because, here, the device becomes a metaphor for death - the supple, pliant women communicating a kind of final yielding up of the will as they are carried from one phase of life to another.

Jean Allenby and Kurt Speker in the first duet and Susanne Hanke and Christopher Boatwright in the second moved through their ritual involutions with smooth-flowing tension.

Whatever one's misgivings about "Camellias," Marcia Haydee danced Marguerite Saturday afternoon with enough passion and phthistic frailty to assure full-catharsis for all assembled and present for the final act. The performance took off somewhere in the middle of Act II and never touched ground again.With Haydee, with her odd expressive face and appealing, angular manner, you always feel there's a genuine person up there dancing, and not just a China doll. Egon Madsen was a passionate-enough Armand to set what must surely be the Egon Madsen fan-club raving afterwards - though I thought the betrayal scene a trifle overblown. As a weary Manon Lescaut in the last act of "Camellias" and as the pale and bookish Tatiana transformed by awakening sexual passion in the dream sequence of "Onegin" at the Sunday matinee, Lucia Montagnon was light and supple, dancing with a pure musical fluency, and with that extra throw-away quality that makes a performance memorable.