Passion never kindled. And artificial insemination didn't work. Now National Zoo officials are hoping a good, panda-sized dose of jealousy will do the trick of producing a baby for Ling-Ling, the zoo's female panda.

Chia-Chia, a British suitor who pronounces his name Cha-Cha, will soon call on the lady. And while her erstwhile lover, Hsing-Hsing, watches from an adjoining room, Ling-Ling will spend the panda-breeding season, which occurs only five days a year sometime in April or May, flirting with Chia-Chia.

The hope among zoo officials is that Chia-Chia will feel the competition from Hsing-Hsing and make a pass or two at Ling-Ling.

"We hope Hsing-Hsing will be an interested observer and that the presence of another male will be quite stimulating," zoo director Theodore H. Reed said with a glint in his eye at a press conference yesterday.

If a baby is conceived, Reed said the National Zoo, will monitor the 118-168-day gestation period and attempt to raise the panda to maturity. Eventually, it would be turned over to the London Zoo.

Reed said Chia-Chia, a healthy, 240-pound, 8-year-old virgin, will arrive in New York City on March 5 aboard a British Airways freighter. He will then be trucked to Washington. Chia-Chia will be given three days to recuperate from jet lag and adjust to his temporary home before being placed on public view. Then the matchmaking begins.

As the mating season approaches, zoo keepers and the public will look for the tell-tale signs of a female panda in heat. According to zoo officials, Ling-Ling will become restless. Her appetite will wane. She'll occasionally walk backwards, sometimes making a bleeting sound like a sheep. And a gland in her body will release a distinct odor that will permeate her enclosed room and outside yard as she rolls around in the grass and rubs against objects.

Chia-Chia and Hsing-Hsing will watch the ritual through wire-mesh screens from their separate rooms. And from time to time, Chia-Chia will be released into Ling-Ling's outside yard to learn her scent for the right moment for mating.

Reed said the rejected Hsing-Hsing will get extra apples and honey, and be placed on standby if for some unforseen reason Ling-Ling violently rejects Chia-Chia.

In six years together, Ling-Ling and Hsing-Hsing have not conceived. Though Hsing-Hsing has been tested as medically sound, zoo officials say he has fizzled as a lover and they, along with Ling-Ling, are fed up.

"The poor male has only five days to breed out of a year," Reed said, with some compassion. "Although he has tried, he hasn't had much experience. He knows he has to do something."

The problem is he hasn't figured out what and this year he won't get the chance.