The mixed bill that Houston Ballet brought to Wolf Trap was one of popular pieces. Classics are sometimes austere and easy to spoil. Warhorses like Harald Lander's "Etudes," Ben Stevenson's "Three Preludes," Marius Petipa's "Don Quixote" duo and, yes, George Balanchine's "Serenade" are so sturdy that they permit a certain latitude of style. The dancers enjoy themselves and the audience, sensing it, responds with relish -- which was certainly the case on Thursday night.

That's not to say any of this choreography is dancer-proof or unchallenging. "Etudes" calls for every facet of ballet technique, but it can be performed for virtuosity's sake or as a set of mood pieces. Houston achieved a blend of both, from ballerina Mary McKendry to the women and men of the corps. McKendry was especially eloquent in the Sylphide scene and powerful in the leap passages. The turn sections were underdanced, which was surprising after her strong Aurora in "Sleeping Beauty" on Wednesday.

Technique and feeling can't be blended in "Three Preludes." This duo-drama is about the dialogue that exists between the dancers' work and personal commitment. Yet it's possible to just allude to the tensions and harmonies of the dancer's lot or be more specific. Janie Parker was quite definite about what was troubling or gratifying her, Edward Warburton less so -- not because of a different idea of acting but because he was too busy with the partnering. He's a dancer, though, with a good line.

Parker was overly specific, too facial in her acting for "Serenade." The opening women's ensemble was performed softer than New York City Ballet dances the work even now, in its post-Balanchine days. Houston's lyrical women, though, attained a speed and vitality that didn't sentimentalize this hymn to the attraction of the eternally feminine. Lauren Anderson, intersecting and leading the remarkable group patterns of the first movement, embodied grandeur through the energy of her dancing. Her leap had a snap that was heroically poignant, her turns were tight with determination. Jeanne Doornbos, though less expressive, suggested fatality in her streamlining. Alas -- Parker, in the pathetic role, was sometimes so sluggish she seemed a masochist, not a martyr. The end of the ballet, which she dominates, fell apart.

With Li Cunxin injured, Houston's male strength is depleted. John Grensback, who stepped in for Cunxin in the "Don Q," boasts lightning legwork that's too quick: It looks rushed. Perhaps more stretch would unhurry it. Grensback's ballerina, Rachel Jonell Beard, reveled in balances, footwork and a femininity that was earthy rather than eternal.