It was just a few minutes before dawn when 30-year-old Antonio Luna heard the voice at the window. "Where are you from?" It was asking in Spanish. "What is your name?"

As he snapped awake he could hear shouts, see people running. Luna and other men in the bunks around him panicked.

"La migra" - the United States Immigration and naturalization Service - had come to get them. It was an encounter that Luna, a Mexican, had been dreading for the five years he has worked illegally in the United States as a migrant vegetable picker.

Among the barracks of the Somerset Camp near Westover, Md. - where Luna and about 900 other migrants live during the tomato and cucumber harvest season - dozens of illegal immigrants were suddenly in flight.

INS officer Robert Short, who directed the operation at Westover and all up and down the Eastern Shore during the closing days of the week, said his 27 men had waited until some people had begun to stir before questioning them, but then things went wild.

The first illegal worker apprehended, said Short, had walked out of his room, seen a uniformed officer, turned to run and plunged straight into Short's arms.

Some were reportedly diving out of windows, sprinting from the dilapidated buildings that had once been a World War II prisoner-of-war camp through the mired roads toward the woods and high stands of corn. Many of them wore nothing but their underclothes.

Scenes like the one at Westover Thursday and at other camps a little farther north near Hurlock Friday have become almost annual occurences on the Eastern Shore - part of a cyclical drama of need, frustration and determination.

"They (INS came just like they do every year," said Roberto Gonzales, a Mexican-American migrant who witnessed the scene. "They took them off in handcuffs like they had killed somebody or something."

Immigration officers, as even many illegals will say, are simply doing their jobs. But the people they apprehend feel, more often than not, that they are simply doing their jobs as well.

The raids on the Eastern Shore this week epitomized the complexities and paradoxes brought on by the government's attempts to cope with the tide of hundreds of thousands of illegal immigrants coming to the United States each year.

The majority of illegal workers come across the long border from Mexico, though quantities of illegal immigrants from just about every part of the world come to work in this country. Many see jobs in this country as the only means available of supporting their impoverished families.

They find their ways to the factories, restaurants and hotels of the big cities, to the citrus groves of the Southwest, and into the three major streams of migrants that circulate through the United States following the harvest of fruits and vegetables that can be picked only by hand.

Estimates of the total number of migrant farm workers vary from 500,000 to about a million. Though illegals may be a substantial minority among these workers, it is impossible to estimate how many there are, INS officials say.

Each year between 10,000 and 12,000 migrants come to the Delmarva peninsula as part of the East Coast migrant stream. These migrants begin their work in Florida early in the spring and follow the ripening of such vegetables as cucumbers and tomatoes northward through the Carolinas until they arrive on the Eastern Shore early in July.

They usually stay about six weeks. Some then move on north to Pennsylvania and Long Island while others return to Florida to await the beginning of the citrus season in October.

Last year and again this year, about 100 illegals were caught among Maryland's migrants. In the hectic atmosphere of raids such as the one at Somerset, it can only be guessed how many illegals avoid detection.

When the INS agents came into the camp at Westover, "Everybody was sleeping," recalled one young migrant. "Then everybody was running."

Others stayed calm. "I'm an American, man," some told INS officials.

Many showed their papers: birth certificates, and "green cards" if they were legal immigrants. Though some may have talked their way out of arrest the majority of the immigrants were telling the truth, Sherl said.

According to Short, if an investigator doubts the word of a person he suspects is working illegally, he has the right to question the person so long as the interrogation takes place within 100 miles of any U.S. border.

Some, however, escape if they are familiar enough with the geography and details of life in the United States town where they claim to be born.

As scores of interrogations went on at Westover, several INS agents were in hot pursuit of those who would not or could not make such a defense. As the sun came up, hundreds of migrants stood watching as 57 men were loaded into vans and taken to the Somerset County jail. There they waited, along with about a dozen men picked up in other Eastern Shore raids, for the bus that would eventually take them back to Mexico.

Such raids cause deep resentment, both among many of the migrants and among the farmers who hire them. INS officers find themselves the subject of considerable antipathy as they try to enforce laws directed against people who - far from causing clear and apparent dangers to the community - are often seen as valuable contributors to its economy.

Immigration raids occurred last year at the peak of the harvest season, causing strident protests from some tomato farmers whose crops were left rotting in the fluids.

This year INS did not begin to arrest illegal migrants until after the rains had cut the tomato harvest short. Though many residents of the area thought that might have been a conscious move on the part of government officials, Short of INS said it was merely coincidence, and that the raids were timed to occur when the most migrants would be in the area.

Nevertheless, many farmers were angered by the raids that took INS officers into their fields.

"They're chasing the only people willing to work around here," complained one farmer.

"Do you think we'd bother with these camps if we could get local people to work?" said farmer Charles Fisher, one of 13 stockholders in the Westover camp. "But we cannot get it done. You know, we can plant these crops, but these people are the most important part of the operation."

The life of a migrant picker is one to which many illegals adapt with ease. In Mexico, for instance, a man may do much the same kind of labor for as little as $2 a day. As a migrant in the United States he may earn anywhere from $20 to $60, and the very best pickers, according to some migrants, may earn $100 a day if conditions are right.

The lure is apparent, and illegals, according to many farmers and crew leaders, are some of the very best pickers.

As crew leader Eugenio Herrera put it, "These people work like machines."

"Some of these local people wouldn't pick a cucumber if it got in bed with them," said another crew leader, George Bostwick, who originally came to the United States from the Bahamas.

Black migrants - including some illegal West Indians, though the vast majority are American - account for most of the pickers on the Eastern Shore.

However, the proportion of Hispanic crews has been growing, and they bring with them a distinct culture, different from that of the predominantly black crews or the white workers.

"A lot of the black migrants are scrounged out of the cities," said Abigail Tamayo, a bilingual nurse at Westover. "But the Mexicans have been working in the fields all their lives."

Most of the migrant crews on the Eastern Shore, moreover, come from Florida or Texas - states where there are already large indigenous Spanish-speaking populations.

The work crews, averaging about 35 to 40 people, are brought together by men and women called crew leaders, who are responsible to the farmers for the work their people do and unusally handle most of the money and administrative affairs.

Many Hispanic migrants travel with their families and the crew leader may eventually become a sort of "padrone," th head of a large clan.

Such an environment - despite living conditions many Americans would find appalling - may be another attraction for illegal immigrants.

"If a crew leader treats his people right," said Maria Herrera, who helps her husband run his crew, "then people will go with him."

She also suggested that INS may inadvertently be helping attract illegals. "They catch these guys and so they go back to Mexico," said Herrera. "But they know which crew leaders are best. They know about the money. And then they come back and bring some friends with them."

Such a journey is not without risks. Smugglers called coyotes are often paid to take the illegals across the border, for prices raning from $175 to $250, according to INS officials.

Often the illegal travels with his life savings on him to help him get started. "A lot of these smugglers," said Juan Campos, a longtime migrant from Texas, "they see these guys have got $600 or $700 and they can get killed even for that."