In historic downtown Gaithersburg last weekend, members of the venerable Lions Club, in bright yellow aprons, offered up free vision screening and popcorn fresh from an old-fashioned machine.

Just one thing was out of synch with this scene of 1950s Americana: The Lions were all Latino.

As a large immigrant middle class emerges in the United States, its members are joining mainstream civic groups, which until recent years had nearly all-white rosters. Across the nation, Latinos and Asian Americans are being courted by the 88-year-old Lions organization and other civic clubs. The Montgomery County Latino Lions is one of four clubs in the Washington region with predominantly immigrant membership.

Ernesto Diaz of Rockville considers being a civic volunteer a sign that he has made it in this country.

"When you come to the States, you come with the mentality of making money and succeeding. You don't think about society," said Diaz, 55, once a waiter and now director of logistics for Balducci's, a gourmet food chain. "After you are here for years, you start to think about those things."

The immigrants, in turn, may be key to the service clubs' future.

The Lions organization has lost 80,000 members in the United States in the past decade, bringing total membership down to 420,000. Nationally, fewer than 10 percent of Lions clubs are predominantly immigrants, but their groups are among the newest. Members of the ethnic Lions clubs also tend to be younger than their counterparts: under 60.

"We need them," said Edward "Woody" Woodward, 70, governor of the Lions' Northern Virginia district. "Us old folks are going to be passing on."

Once a staple of white, middle-class life, civic groups such as the Lions, Kiwanis and Rotary have become better known as home of the ROMEO -- Really Old Men Eating Out. The average age, some members joke, is deceased.

As people have become more pressed for time, fewer can make a commitment to a monthly civic group meeting. A far wider array of social and professional groups has become available. Membership in Lions or Rotary clubs is no longer needed to burnish a resume or forge business connections.

Many immigrants have a different view. In their home countries, groups such as the Lions and Rotary -- which have international chapters -- are still a symbol of middle-class society.

"I never thought I would be a Lion again," said Diaz, who is now the Latino club's president, or "King Lion."

Carlos Devis, a Potomac resident originally from Colombia, said joining the larger Lions network gives the immigrants more credibility and resources when doing volunteer work. "If we go in as Latino parents or the Colombian association, they don't know us," said Devis, 51, a consultant to Montgomery County schools. "If we go in as Lions, they know."

The Montgomery County Latino Lions, with 24 members, started a year ago with the help of the Rockville chapter; one of Rockville's leaders is Diaz's neighbor and recruited him.

The South Potomac Lions in Prince George's County nearly folded until a couple of Filipino immigrants were recruited eight years ago. Now, the club has 28 members, nearly all Filipino.

In the District, a small Chinese American Lions club is based in Chinatown, but there is talk of moving to or starting another in the suburbs, where most Chinese immigrants now live. Northern Virginia has an Asian American Lions Club based in Alexandria. Although the immigrants are free to join other Lions chapters, many say they feel more comfortable in a club whose members have the same ethnicity because of language and culture.

Regionally, there are a few Latino and Asian American members of Rotary clubs, but no chapters made up of a single ethnic group exist. A small number of black members have joined the Lions and other groups. But with a longer history in this country, African Americans also have established large and respected professional and civic organizations.

Social scientists say immigrant families typically have taken two generations to join such mainstream groups as the Lions. But the first-generation immigrants may be assimilating quicker now because U.S. society is more inclusive.

Although the Lions and other civic groups never had a policy against admitting minorities, membership is by invitation. Club leaders say the organizations have reflected the segregation of the times. Women were barred from membership until the late 1980s -- when the U.S. Supreme Court stepped in. The court, in a case filed against the Rotary, ruled in 1987 that because of its size and ties to the business community, the civic club could not bar women.

Jose Mararac of Accokeek said he joined the South Potomac Lions because of fellow Filipino immigrants, but the club has been an entree for meeting people beyond his community.

Previously, he had been primarily involved in a "hometown" association, common among immigrants, that was limited to Filipinos from his home province.

The Lions club is "a lot of volunteer work -- the eye bank, blood drives," said Mararac, 66, now the group's president. "You get to be a part of the community, to get to know other people."

"I learn how to network," said Mararac, a Realtor, who added, "You need to buy a house?"

Mararac and other immigrant Lions say there are few differences between the predominantly immigrant chapters and the others. Each group holds monthly meetings in a similar format: the Pledge of Allegiance, the Lions song and a meal. Lions members are expected to hold fundraisers and contribute money.

The key difference is language. Latino Lions often conducts their meetings in Spanish, although members will switch to English if a visitor from another club who doesn't speak Spanish is in attendance. And because the members are bilingual, their focus has been on helping disadvantaged fellow immigrants.

At the Olde Towne Gaithersburg festival Sunday, almost as many non-Latinos as Latinos came by the blue-and-yellow Lions health bus. After 90 minutes, 47 people had had their vision and hearing screened.

Visitor No. 48 was a top member of the establishment: J. Thomas Manger, the county's chief of police.

His vision is 20/20, although he needs reading glasses. And his hearing is perfect.

"That means you can receive the complaints of the Latino community," Diaz said as Manger stepped out of the hearing test booth. "You've been checked by the Lions."

Manger chuckled -- and nodded.

Latino Lions club member Ernesto Diaz reviews hearing and vision test results with Mirna Colindre, left, and her daughter, Maryuri Hernandez, 8. At right is Lion Susie Carpio-Diaz.At right, Carlos Devis helps administer a hearing test on Alexandra Kudla who is originally from Poland.