It's a sad, rather frightening fact that most modern dance companies last only as long as their mentors. Despite film and video and various notational systems, this all-too-human art form depends almost exclusively on individuals rather than organizations, and tends to rebuff technology in favor of living, breathing Grahams, Cunninghams and Taylors.

So just what does a company do when their creative parent is no more? The Joyce Trisler Danscompany intends to find out. This small, 6-year-old troupe [appearing at the Terrace Theater tomorrow through Sunday] was left reeling last October when Trisler --their choreographer, artistic director and guiding spirit -- died of a heart attack at the age of 45. A warm, comical woman, she embodied a rich blend of American modern dance trends.

Born in Los Angeles, she began her career as a teen-aged dancer with the Lester Horton Dance Theater, a multi-racial, ethnically-oriented company whose members included Alvin Ailey Carmen de Lavallade and Bella Lewitsky. Later, under Doris Humphrey's tutelage, Trisler performed leading roles with the Juillard Dance Theater, and subsequently danced with her friend Ailey's troupe, one of the white members of this notably integrated group.

Trisler's choreographic career took equally diverse directions. She made dances for concert stages, industrial shows, musical theater, even opera productions. She'd formed a repertory company back in the late '50s, but the present Danscompany was for her the high point, the hope.

"Joyce was really an incredible lady," muses "milton myers, the young black dynamo who has just assumed artistic responsibility for the company."It's such a loss. She had so much more in her." Myers, a former Trisler dancer and protege currently finishing out his contract as a member of Ailey's troupe, simply bubbles as he discusses his teacher, her work and his plans for the New York-based Danscompany.

"It was a special situation with Joyce," he remembers. "She took a real interest in me. When she was sick and couldn't teach she would make me go and teach. When she was choreographing I was right behind her." Myers' experience falls right into that old modern dance generation-to-generation, body-to-body history.

"I think what Joyce gave the company was a way of moving and doing," he explains. "I think this company has something different -- a real attack, anenergy that comes from underneath. When I was dancing her work, it always reminded me of a hummingbird, standing still but..." His hand quivers descriptively as he speaks. "That's what the company has to maintain, and it may be hard for the newer kids."

Myers has his hands full. The majority of his dancers are young, ballet-trained, technically gifted but somewhat unfamiliar with the real basics: weight, punch, drive. These qualities are crucial to Trisler's choreography, as well as the rest of the company's repetoire by such notables as Horton, Ailey, Talley, Beatty and Donald McKayle. "The Spirit of Denishawn," Danscompany's celebrated recreation of early 20th-century dances by Ruth St. Denis and Ted Shawn, demands constant polishing. And, of course, Myers himself wants to choreograph.

For now, Danscompany's concentrating on the present and the immediate future. Just back from a critically acclaimed season in Paris, the dancers are ready to take on Washington, the Spoleto Festival in Charleston, Munich, Brussels, even the experts in New York City. But the long-range question of artistic and financial survival still looms large and depends completely on Danscompany's care and feeding of Trisler's vibrant legacy.