The guests at Margaret Cheeseman's American art gallery opening last night were of two groups. First, there were sedate well-dressed Latins speaking Spanish softly, studying the art closely. This group, for the most part, had never heard of Margaret Cheeseman. The second group were older, cheerful, smiling businessmen and lawyers with their wifes all in bright Lilly Pulitzer-colored clothes, talking with a touch of Southern accents. This group has known Margaret Cheeseman most of her life, and many called her "Missy" last night.

Margaret Cheeseman is 31, blond, very tan and sixth-generation Alexandria.

Her father is head of Robinson Terminal Warehouse Corp. She lives in Venezuela with her businessman husbanb,Robert Owen, who is a Canadian citizen raised in Venezuela and so acclimated to that part of the world that he acts and sounds more Latin Americanthan North American. Ever since her husband -- whom she met at Tulane University -- wooed her into marriage and life in Caracas 6 1/2 years ago, Cheeseman has been painting pictures of Venezuelan people whom she seeks out inthe mountains and beaches and interior of Venezuela (but never Caracas.)

Hence, it seemed quite normal to havesuch a mix filling the gallery space on the ground floor of the Inter-American Development Bank, which Uraguayan artist Naul Ojeda and his wife Philomena noted was one of the nicest pieces of gallery space in the city. (Naul Ojeda did not know Margaret Cheeseman either. He came simply to see the new exhibit of Latin art.)

Cheeseman paints Venezuelans of different colors and life styles from the photographs that she snaps of them. Some of her subjects panicked when they saw her coming, others primped.

Once Cheeseman, who speaks good Spanish, found some Venezuelan women in a market. "I knew they were superstitious," she said, "and they felt the camara takes the spirit away. But I saw them, and I knew it was something I wanted. So I just turned around, focused may camara, turned back, guilty, but on the other hand they were so beautiful."

"I bought this fella here," said a lawyer, one of her family's friends, pointing to a small painting of a beggarchuckling. "I don't know if he's a lawyer or not. He's got a stick in hishand."

Cheeseman has had exhibitions in galleries in Caracas, but never before in Washington. "Most galleries here in Washington said, 'It's too big and it's Latin -- get out,'" said Cheeseman, who noted that she went to about eight or 10 galleries. "I tried the OAS (Organization of American States) and they said, 'No, you have to be Latin.' Then I applied a year ago for this."

She is one of only a handful of American artists who will exhibit this year at the bank.

"Actually I've been misunderstood a lot," she said, wincing. "Most Latin art is symbolic. My art is juststraightforward -- so American."

A local artist looked Margaret Cheeseman's work over. "As a body, it's nice," she said politely. "But it's not particulary spontaneous."