There's an untold story behind the stark figures that show fewer blacks and minority students in college today. The colleges and universities are no longer recruiting them seriously, if their incomes are low. Admissions directors are still going after the superblacks, with top grades or special athletic talent. But for the average inner-city student, the open door of a decade ago is swinging shut.

The reason is money. The federal government quit adding big bucks to the programs that help educate lower-income youngsters, and private sources can't fill the gap.

"The economically deprived need many thousands of dollars to meet college costs," says Charles Marshall of the National Association of College Admissions Counselors, "and the schools are no longer in a position to offer them a full package of aid. Rather than raising false hopes among these students, the college recruiters are staying away."

Low-income students may have other choices. Many are going to inexpensive two-year community colleges, financial-aid expert Robert Leider told my associate, Virginia Wilson, and they might make it into a four-year college later. But finding the money will still be hard.

Here's what is happening to college aid, and the extent to which its loss has narrowed the world for a generation of the neediest students:

*Low-income students depend primarily on federal grants. But the size of the average Pell grant (now $1,089) has not kept up with tuition inflation, so it covers a much smaller portion of college costs than it did a decade ago. The purchasing power of the maximum Pell for the very poorest students ($1,900) is down even more.

*The G.I. bill for Vietnam-era veterans started running out toward the end of the 1970s; education benefits through Social Security started phasing out in 1982. Both programs were disproportionately used by lower-income people. In theory, Pell grants and other federal programs should have taken up the slack for the truly needy, but they never did.

*Since 1980, the amount of federal money allotted to National Direct Student Loans has been cut nearly in half. The colleges make these loans to the neediest students, at only 5 percent interest. The big loss of funds, along with other problems in the program, has led directly to a substantial decline in the number of blacks in graduate schools, reports Mary Carter-Williams of the Institute for the Study of Educational Policy at Howard University.

*A handful of states have increased the total amount of aid they give to low-income students, but many others are giving less. A study done for the National Association of State Scholarship and Grant Programs shows that the average amount of state aid per needy student has declined.

*According to the National Student Aid Coalition, the talented but poor are 20 to 25 percent less likely to go to college than their wealthier peers; the poor of average ability are 40 percent less likely to get a college education.

One important point should be made about the access of low-income people to college. A study done for the American Council on Education shows that from 1974 to 1981, before the Reagan administration's scholarship cuts, the percentage of low-income blacks in college declined while the percentage of low-income white students was going up.

Those were years when inflation was badly eroding the value of financial aid, but why did it have a more harmful effect on minority students? The answer, Marshall believes, lies in the better counseling often available to students in predominantly white high schools.

Linda Berkshire of the National Student Aid Coalition says that many minority students don't know much about student aid, don't get enough personal counseling in their schools and don't have ready access to up-to-date reference material. The application forms are hard to fill in, especially for parents who have never had to struggle with the opaque language of personal finance. Some parents simply refuse to cooperate.

The smart and aggressive among the high-school counselors in inner-city schools are struggling for ways to meet the problem. They offer seminars on finding financial aid. They help parents fill in the application forms. They try to get students thinking early about college, to allow more time for financial planning.

Although their efforts can squeeze out more dollars from present programs for eligible students, they cannot awaken those of careless social conscience to the waste and tragedy of the unnecessarily undereducated. Taking money out of higher-education programs for the poor is a decision this country will come to regret.