About 250 people were expected at last night's black-tie reception at the Meridian House, just off 16th Street, that marked the beginning of the 11th annual International Children's Festival. Fewer than 100 guests attended. There were substitutes for the substitutes. One embassy official sent his housekeeper.

"Labor Day weekend, what do you expect," she said, sipping a cocktail. "I wish I wasn't so nervous."

The honorary sponsor of the evening, Jane Weinberger, wife of Secretary of Defense Caspar Weinberger, didn't even make the party. Instead, Jay Rixse, the secretary's special assistant, and his wife, Terry, greeted guests, among them Peter Towe, ambassador to Canada and his wife, Carol, and Richard Berendzen, president of American University. "This is a super program," said Rixse. "It's great for the children and the adults will enjoy it as well." About 20,000 people are expected to attend the performances at Wolf Trap over the weekend.

Several of the child performers, who came from around the world to appear in the festival, entertained the guests. Lisa Clohisy, 19, of the Christina Heimlich dancers, has particpated in all 11 festivals. "For me, they were part of growing up," she said. "I've met so many people doing this. It really is communication through art."