A new phrase has entered the cultural lexicon here: "Black Tag People."

Texans use it to describe the unemployed migrants from Michigan, whose cars bear black license plates with white lettering, and who are seen increasingly on the freeways around the major cities of Texas.

The phrase has an eerie, sinister sound, a slip of the tongue away from "Black Plague People," and indeed, that is the way the newcomers are now seen by many of the longtime residents of this state.

The phrase has been picked up by pollster Lance Tarrance of Houston, who says his employes are hearing it more often these days from the people they are surveying.

To read the newspapers and watch television news here for the last six months or so is to understand how the Michiganders have become cast as Black Tag People.

There is no doubt that many of these newcomers--whether from Michigan or Ohio or New York or some other northern state suffering from the defects of the country's old industrial economy--are in trouble.

Out of work, semi-skilled, possessing few personal resources, this largely white group has come south in search of better job opportunities. Once arrived, many have found the job mecca to be a myth. For the skilled worker, jobs are often easy to find; for the unskilled, they are increasingly difficult.

Sometime early in the year, the Texas news media seized on a new image of the northern immigrants. Until that time, the newcomers were, in composite terms, well-educated, middle- and upper-middle class, relatively conservative and suburban-oriented. In short, a blessing to the state.

Since then, the image has changed dramatically.

To begin with, the newcomers are now universally referred to as Yankees, and that is not a term of endearment here. And they seem to be in the most terrible of predicaments.

These Yankees are now found increasingly in pawnshops, hocking their few possessions to buy a meal; in soup kitchen lines in the inner cities of Houston and Dallas; huddled in broken-down campers near a downtown park; at the unemployment offices applying for out-of-state benefits; at the churches along the interstate highways that flow from the north, seeking emergency food assistance or money to fix a broken car; at the welfare office asking about benefits; at child welfare homes asking someone else to care for their children because they have been unable to find work.

Their stories carom from city to city in a matter of days. If one newspaper writes about Yankees in pawnshops one day, the television stations in another city do the same story the following day. There is a race on now to find the latest example of the problems facing these migrants.

They are now treated in pathetic ways, as if they are the new benchmark of poverty. Longstanding poverty among east Texas blacks and Mexican Americans in south Texas has given way to the desperate plight of the Black Tag People. They are the Okies of the 1980s, but there is no sympathy being generated for their condition. Quite the opposite.

The continual flow of news about the down-and-out newcomers has had the more predictable effect of creating a new scapegoat for the economic ills that increasingly plague Texas. When the unemployment rate in Texas jumped to 7 percent in June, the press secretary to Gov. William P. Clements Jr. was quoted as saying the increase was proof that Texas could not provide jobs to every unemployed autoworker from Michigan.

Such hostility is now commonplace in Texas, an ugly byproduct of the economic success story that Texas and other southwestern states have written in the last decade.