As the annual display of Hispanic presence in the nation's capital began yesterday, thousands of immigrants from south of the border lined Columbia Road to celebrate success in a new land with the familiar food and festivities of their fatherlands.

But for one group of immigrants, the 15th Annual Hispanic Festival was a day they'd just as soon forget. Indeed, they themselves have been all but forgotten.

Unlike most newcomers to what is considered the most culturally diverse neighborhood in the Washington area, the 500 Marielito Cubans -- named for the port of Mariel from which they were put out of their country in the 1980 boat lift -- who live in and around Adams-Morgan have found only culture shock and despair.

Instead of blending in, they have become the outcasts of the immigrant class. Mostly black, often illiterate and unable to afford haircuts or new clothes, they are feared and shunned by local residents and fellow immigrants alike.

"A day like this doesn't mean much to them," said A.A. Sylvester, a D.C. police officer who patrols Adams-Morgan. "They don't have three dollars for a plate of food. They aren't even familiar with the concept of carrying money in the pocket. They are barely surviving."

Jose Julio Ofarril, who came to Washington from Cuba five years ago, is one of them. Through an interpreter, he said he had been notified that his refugee adjustment allowance has been terminated, and he is now forced to borrow from friends.

"I don't drink. I don't smoke marijuana. I don't commit crimes," Ofarril said. "I have no money, and it's hectic."

"He's a decent fellow," said Ahisel Rodriguez, a white Cuban who came to Washington in 1961 and now lives on Social Security. "He says he believes that racial discrimination is the problem."

It is a belief shared by others, including the community-based Afro Latino Institute, which has been trying to persuade area business persons to hire the black Cubans. But the word is out among business persons and landlords: the Mariels are trouble.

"I don't want any of those people in here because they drive away customers," said one Columbia Road businesswoman who asked for anonymity. "They show up late for work and they don't bathe. There are too many people willing to work hard to take chances with them."

The result of this bad rap is that intense frustration and desperation has set in among the Mariels, some of whom suffered from mental illness and disease before their arrival.

During the past five years, police say, at least 10 Mariel Cubans have been murder victims, often at the hands of other Cubans. Of the 500 who live here, about 100 have served time in the D.C. Jail and Lorton Reformatory, and about half have had some kind of contact with law enforcement officials, police say.

Other than efforts by the Afro Latin Institute, little has been done to integrate the black Cubans, and although their problems have been largely ignored, it's not likely to stay that way.

"The chickens could come home to roost with these guys," Officer Sylvester said. "It hurts me to hear what people say about them, because most of it is not true. But it could come true if they are allowed to exist on the fringes much longer."

Shortly after the festivities began yesterday, three young Marielitos left the main street and took refuge on the stoop of an abandoned building. They were indeed curious about what was happening, but without speaking English -- or even Spanish -- articulately, even their most elementary efforts at communication backfired.

"Honey, honey," they called out to a woman who walked past them. The woman frowned in disgust at the Mariels, who wore no shirts or shoes.

The men became silent, then suddenly started yelling at each other playfully. A punch was thrown, but instead of fighting back one of the men began to sing, "Recuerdo Tu Amor" ("I Remember Your Love"), which made the others laugh.

A deep melancholy settled on their dark and drawn faces, and the singer tried another refrain. But like their problems, his voice was barely noticeable amid the banter of the festival in the streets.