What was going on when I was born?

Gov. William A. O'Neill today signed legislation making Connecticut the first state, according to Connecticut officials, to authorize urban ''enterprise zones'' designed to stimulate economic development in depressed areas of cities. The 10 percent state corporate income tax will be cut in half for 10 years for manufacturing businesses that locate in these zones provided that 30 percent of their employees live in the zones. Any manufacturing business that locates in the zones will also receive $1,000 grants for each job created and will be given an 80 percent reduction in local property taxes for five years. State-financed training assistance will be provided for employees who are hired locally. The law does not specify who is eligible for such training assistance, but state officials said the intention was to train unskilled, unemployed workers who live in the zone. .

With the summer cycling season in full swing, New York City officials have begun a ''safety offensive'' that they hope will reduce the number of accidents involving bicycles in traffic. For the first time, seven traffic-control agents and two police officers have been assigned full time to try to keep motor vehicles, bicycles and pedestrians separate on the city's roadways. The traffic agents are being posted at intersections where there have been unusually large numbers of accidents involving pedestrians. The police officers will concentrate on giving summonses to motorists and cyclists who disobey traffic laws.

WASHINGTON Although its glamorous sister, the Consumer Price Index, gets more public attention, it is the Producer Price Index that corporate strategists, bond traders, economic forecasters and other professionals regard as the more important measure of inflation. "The P.P.I. is probably a better estimator of developing inflationary pressure," says Donald Ratajczak, a forecaster at Georgia State University and a student of the subject. "If you're a good reader of the P.P.I. you'll know three months ahead" what's happening to certain prices at retail. But the Producer Price Index, which will be released on July 7 for the month of June, is not a secret key that can be used to unlock the economic future. In recent years, in fact, the explosion in oil prices has exposed its shortcomings as a predictor of consumer prices even as the Government has moved to increase its overall utility.

FIRST By JANE E. BRODY ITHACA, N.Y. THOUGH it may seem like a sick joke to those whose vacations are now being ruined by the persistent and painful bites of black flies, Edward Cupp, an entomologist at Cornell University, spent five years and about $150,000 figuring out how to mass-breed the pesky creatures in his laboratory. As Dr. Cupp sees it, establishing continuously breeding colonies of black flies in a controllable environment is the crucial first step in developing better ways to get rid of them. The method developed to breed the flies illustrates how inventive scientists often must be to solve a seemingly straightforward research problem. The blood-sucking flies, found throughout the United States wherever there is unpolluted fresh-running water, are daytime biters that slash through skin with scissor-like mouth parts and have little or no respect for the usual deterrents.

An article in Business Day yesterday gave a wrong first name for the Yale University expert on occupational health who has studied exposure to asbestos. He is Dr. Robert Sawyer.

A 32-year-old man who was seized while carrying a bloodstained straight razor was charged by the police yesterday with murdering one vagrant and with menacing another. The city's Chief of Detectives, James T. Sullivan, said the police believed that the man was responsible for the recent series of throat-slashing attacks that left two men dead and 13 wounded. The suspect was identified as Charles Sears, whose last known address was the Hotel Delevan at 143 Bowery. He was said to have a criminal record. Chief Sullivan said, ''We do not have the motive for the attacks at this time.''

France's state-controlled oil company, Societe Nationale Elf Aquitaine, agreed after negotiations yesterday to sweeten its $2.5 billion bid for Texasgulf Inc., one of the world's largest sulfur producers, to $2.8 billion in cash. Texasgulf's directors immediately gave their support to the revised takeover bid. A spokesman for Elf Aquitaine said his company was ''very happy'' with the new proposal - $56 a share for the common stock and $178.49 for the preferred - and was looking forward to ''proceeding with the offer in a friendly and constructive manner.''

After several years of efforts to improve two of New York City's most troubled high schools, Benjamin Franklin and Charles Evans Hughes, officials have decided to phase out their enrollments and reopen them again as new institutions. The two schools, with histories of poor attendance and low academic achievement, have the lowest graduation rates in Manhattan. Hughes, which has 2,110 students and is in the Chelsea section, was picketed last fall by dozens of its teachers, who charged that rampant violence had made their jobs unsafe. Franklin, a school of 1,606 students in East Harlem, was able to graduate only 76 seniors last year, and just nine passed the tests needed to get a Regents diploma.

In the Dining Out column in The Guide on Sunday, an incorrect price was listed for a typical three-course dinner at the Village Green restaurant. The price is $35 a person without drinks.

IT may sound like psychiatric heresy, but behavioral studies increasingly suggest that most normal teen-agers are actually happy. Constant tumult and pain are not the necessary prerequisites for moving on to a tranquil adulthood, according to this research - although a popular and, to some extent, professional perception holds that they are. ''Eighty-five percent of the adolescents we tested report being happy most of the time,'' say Drs. Daniel Offer, Eric Ostrov and Kenneth I. Howard in their forthcoming book, ''The Adolescent, a Psychological Self-Portrait.''

Former President Isabel Martinez de Peron, who has been under house arrest since her overthrow by the military five years ago, was ordered freed on parole today by a federal court. Lawyers for the 50-year-old Mrs. Peron said that her plans were unclear but that she would likely stay in Argentina for a day or two before leaving for either Panama or Spain. They said she would probably seek court permission tomorrow to leave the country. Although Mrs. Peron's appearance in the federal court building had not been announced beforehand, word spread quickly and more than a thousand Peronists were outside to greet her as she emerged.

SECRETS By WALTER SULLIVAN SUNSPOT, N.M. ASTRONOMERS have found that the sun is ringing like a bell, reverberating in a manner that enables scientists at this solarresearch community near Alamogordo to explore for the first time the interior of that enigmatic star. From analysis of the reverberations, some theorists say an inner layer of the sun is rotating faster than the surface, dragging sunspots with it. It also appears that the internal zone of convective motion, or heat-driven churning, extends far deeper than previously thought, reaching a third of the way to the sun's center. Such findings and deductions have raised hopes that more detailed observations will show why the sun behaves in its characteristically cyclic manner. This could explain the long intermissions in sunspot activity that, in the past, have coincided with a severe chilling of the earth's climate.