What was going on when I was born?

In a sweeping move to close the books on a costly and embarrassing trading loss, the nation's largest insurance brokerage concern has dismissed the key managers in its investment department. The move, by Marsh & McLennan Companies, followed weeks of investigation into a $90 million loss after taxes that was tied to trading in long-term government bonds. John M. Regan Jr., the company's chairman, said yesterday that the dismissed employees included the treasurer, the head of its investment management group and the chief bond trader. The company's loss was one of the most spectacular developments in the increasingly volatile government securities market. As interest rates have risen, bond prices have declined sharply, leading to severe losses for some traders and firms. The upheaval in the bond market - prices have fallen by $140 per $1,000 bond since mid-January - has also led to the bankruptcy of two small government securities firms and the loss of more than $25 million to three dozen New York State school districts and counties that had invested money through these firms.

The Senate voted today to delete funds for construction of two military bases in Honduras that were originally sought by President Reagan. The action came on an amendment, offered on behalf of the Administration, to cut $4.4 million from the defense authorization bill for the fiscal year 1985. Jeff Bingaman of New Mexico, a Democrat, had been expected to offer the amendment next week, but John Tower, Republican of Texas, brought it to the Senate floor early this morning in a surprise move as the Senate began its second day of debate on the legislation. Meanwhile, the latest large-scale military exercise involving United States, Honduran and Salvadoran troops ended today and as a result, American officials said, the number of American servicemen in Honduras will be reduced from 1,700 to 700. The officials said no new large-scale exercises were scheduled in Honduras between now and the Presidential elections in November. (Page 3.)

A resurgent economy, a strong dollar and plentiful gasoline are pointing to a big travel summer for Americans at home and abroad, according to government and industry experts. Visits by foreigners to the United States are also expected to reverse a recent downward trend and to rise slightly this year, despite weakening currencies. ''This is going to be an incredible year for Americans overseas,'' said Vivian Deuschl, special assistant to the Under Secretary of Commerce for travel and tourism. The number of new passports issued this year is expected to be 4.7 million, a record, constituting a 12 percent rise over last year's total, which in turn was up 16 percent over 1982, according to the State Department. A record of 599,961 passports were issued last month alone, up 53 percent from the year before, officials said.

Text of statement is on page 6. LONDON, June 8 - Leaders of the seven major industrial democracies called today for ''reasoned dialogue and negotiations'' to resolve conflicts, but they disagreed over a new appeal to the Soviet Union to resume nuclear arms talks. On the second day of their talks at the economic summit conference, the leaders issued a 500-word Declaration on Democratic Values, affirming belief in freedom, equality and progress. American officials expressed disappointment, however, that the statement fell short of their hopes for a specific declaration on negotiating with Moscow.

After a roller-coaster primary campaign, Senator Gary Hart today determinedly pursued plans for winning the Democratic Presidential nomination. But his aides stressed his equal determination to emphasize issues and minimize any discord with Walter F. Mondale. ''He recognizes it's a long shot and will not do anything to hurt the party,'' said his adviser, Patrick H. Caddell. ''But there are other reasons to stay. He represents a large constituency and there are issues and processes that are important to him.''

On a strawberry sundae of a day, all daisies and June sun and pastoral posing by world leaders on the Lancaster House lawn, a professional summit manager came up with a curious new word. It had the charm of corrugated cardboard: snimog. ''Snimog,'' he said, stands for ''sustained non-inflationary market oriented growth'' and, the summit manager explained, the American delegation likes to make certain that the phrase, or one like it, goes into the communiques that come out of summit conferences. Like boilerplate, the final statements bear hundreds of hammer marks and rivets. And in their leaden way, they are perhaps as good a reflection of the mood that dominates the meetings at Lancaster House as the photogenic scenes behind the building this afternoon when President Reagan seemed to want to mow the old building's lawn.

It is not uncommon to see residents of this spirited seaport shade their eyes and stare up at the 12 concrete towers that dwarf everything else in the city. The structures are part of the Government's new 10-story Central Bank building now going up, a project that has stirred a cacophonous debate that threatens to rival the clanking noises of construction. Like many here, Sam Jones considers the building ''not quite proper at this time.'' ''The building may be proper in its own time when conditions of the country have been met,'' the elderly man said, leaning against the wall of a small bakery opposite the construction site. Around him, the narrow streets of the commercial district overflowed with humanity at the start of a sunny day.

A bomb was found aboard a plane just hours before former President Isabel Martinez de Peron was scheduled to board it today to return to Spain, airport authorities said. The airport chief, Maj. Guillermo Mediberry, said there were no indications who was responsible for the bomb - one pound of TNT - that was found by the police in the nose of the Argentine Airlines' Boeing 747. Major Mediberry said the bomb would have destroyed the plane in flight. Mrs. Peron, who left on a different plane, caused bitter divisions in her Peronist Party and its militant unions in her 19-day visit here. Among the almost 300 other passengers scheduled to take the flight bound for Rio de Janeiro, Madrid and Paris were Labor Minister Juan Manuel Casella and a delegation of Government officials and union leaders en route to a conference of the International Labor Organization in Geneva.

The Granadero I exercises formally ended today on a parched dirt airstrip in a tiny valley not far from the border with Nicaragua. As a result, United States officials said, they will lower the American military presence here to fewer than 700 people from the current 1,700. After a Honduran military band had played the national athems of the three countries that took part in the exercises, the United States, Honduras and El Salvador, Gen. John C. Scheidt Jr. of Joint Task Force 7 thanked the Hondurans for ''hosting us and our Salvadoran friends.'' He told the Salvadorans that ''you have an armed force of which you can be proud.''

Two foreign priests and six Filipino lay workers who are charged with multiple murder returned to jail today after rejecting a presidential offer of freedom. President Ferdinand E. Marcos offered to pardon the Columban priests, Brian Gore of Perth, Australia, and Niall O'Brien of Dublin, Ireland, and to parole the lay workers, on the condition that the priests, who are charged with ambushing and murdering a town mayor and four aides in 1982, leave the country immediately.

Defense Minister Moshe Arens announced today that he had decided against outlawing the election slate of a new Arab-Jewish party. He made the decision after meeting for nearly two hours with the leading candidates of the party, called the Progressive List for Peace.

The Indian Army's strike this week against the heart of the militant Sikh movement in Punjab and the killing of the movement's leaders has at least temporarily removed a source of chronic public anxiety. The raid on the holiest Sikh shrine, the Golden Temple in Amritsar, has led to expressions of relief throughout New Delhi, many residents of which have roots in Punjab. There is relief even - or especially - among many Sikhs. It also may well have deflated the two-year- old Punjab political problem and given Prime Minister Indira Gandhi the upper hand in negotiating a settlement. But the raid, in which nearly 400 people were killed, has also inspired anger. Sikhs in many parts of India started bitter protests after the assault on the temple on Wednesday. At least 27 people died in the resulting disturbances.