"Are you discussing space crafts?" inquired the ambassador of Yugoslavia, whom some of his friends think can be quite a card. "Well, why don't we talk about woman and their crafts instead?"

He guffawed the way some men do when that particular subject comes up, but Dr. Ashraf A. Ghorbal, the ambassador of Egypt, could only muster a tentative smile.

Later, Yugoslavia's Dimce Belovski made it only too clear that he really didn't want to talk about women at all or, as he had put it, "their crafts," at the national day reception he and Mrs. Belovski were giving at their R Street NW embassy.

And most certainly, he did not want to talk about one particular woman - Jovanka Broz-Tito, 52, wife of Yugoslav President Tito for 25 years and, as such, the nearest thing that communist country has to a first lady.

Last seen in public on June 14 at a reception for the prime minister of Norway, Jovanka's prolonged absence gave rise this fall to growing reports that she has slipped from favor as one of her husband's small inner circle of advisors. She did not go along last August when Tito visited the Soviet Union (which did not invite her), North Korea and China (itself a country with a former first lady - Madame Mao - currently in disfavor).

Some observers in Yugoslavia saw the slight to Jovanka as Tito's way of publicly dissassociating himself from the women whose power has lain in controlling access to him. Then more recently came stories from Belgrade telling of Tito setting up a commission to investigate his wife's influence over his military and political appointments.

Just last Sunday, Tito, who is 85, turned up at a Yugoslav national day reception in Belgrade. But once again Jovanka was not with him.

Did it mean, Ambassador Belovski was asked yesterday as he welcomed his 500 guests to the Washington version of the celebration, that the investigation of Jovanka was still going on?

"A totally private affair," he said, no longer smiling as he abruptly led his questioner to an embassy aide nearby. "All speculation."

"A private problem," the aide, Dusan Stojkovita, the embassy's second secretary for press and culture, said a few minutes later. "There's no disappearance. In Belgrade, everything is in the open."

"In my opinion," said Howard University Prof. Nicholas Stavrou, who had been talking with Stojkovia, when they suddenly became a threesome, "when a lady has to take care of an 85-year-old man, conserving his energy and time, it might ruffle some feathers of political people who are around. In my opinion."

Still later, after the departures of the ambassadors of Luxembourg, Czechoslovakia, Denmark, India, the Federal Republic of Germany, India, Finland, Singapore, the People's Republic of China, among others, yet another embassy spokesman addressed himself to the mystery of Jovanka Broz-Tito.

"There is a lot of speculation," said press counselor Dusan Trifunovic, expressing some surprise since he said he read only recently that Jovanka's name appears with her husband's on official messages sent abroad on such occasions as national days.

"There is no disappearance, no commission, no investigation," said Trifunovic, nevertheless at a loss to explain Jovanka's absence on Sunday.

"All the stuff about political struggles is pure invention."