Reprinted from yesterday's late editions.

The Lone Ranger used to shout his final "heigh-o Silver" to the accompaniment of the "William Tell" Overture. The Juilliard Quartet is bidding its farewell to Washington for this season with its own theme songs, or music that certainly could be their theme songs.

For their concerts at the Library of Congress Thursday and Friday nights, they opened with Mozart, followed Mozart with Bartok, and closed with what else? - Beethoven, of course.

Each season the Juilliard's programs explore many corners of the string quartet literature, but these three composers seem, somehow, to epitomize what most people think of when they think of the Juilliard.

Perhaps it is because their level of energy seems particularly compatible with this music. Perhaps it is their particularly rich tone that conveys the sense of this music so aptly. Or perhaps it is just that these three are quintessential quartet composers and the Juilliard is a quintessential quartet.

In any case, they are ending this season in a blaze of glory.

Thursday night they emphasized the operatic aspects of Mozart's G Major Quartet K, 387. The piece is pure opera clothed in sonata, minuet - and the rest, guise - and to project this without obscuring the formal outlines or the beautifully proportioned textures is the essence of this music. The Juilliard found an ideal solution.

Bartok's Quartet No. 6 is a more mellow work than the other five but no less vigorous. This performance was notabl for a sense of controlled impetuosity and intense concentration.

Bartok, the architect-composer, introduced each movement with the same material, expanding it gradually until it took over the last movement completely. This is magical music and was particularly beautiful in this performance.

And the Beethoven Quartet opus 59 No. 2 ended the season fittingly, played as only the Juilliard can.