"The magenta Indian chasing the last buffalo over the cerulean blue hills is pretty boring now."

That observation comes from Fritz Scholder, perhaps the best-known of contemporary North American Indian artists. If there are some Indians and buffaloes in the new Smithsonian exhibit on "Contemporary North American Art," it is a far-from-boring show with its diversity of styles and perspectives.

Take "Custer Revisited," a wonderfully witty updated view of the famous last stand. Childish drawings of soldiers and Indians sprawl across a canvas with overturned cars and an Indian brave, bow drawn, in the back of a pickup truck. This is the work of R. Lee White, of the Sioux tribe.

The Smithsonian exhibit, which will run through Sept. 12 at the Museum of Natural History, brings together the work of nearly 65 contemporary Indian artists from about 40 tribes. It was mounted by the Smithsonian with the help of Amerindian, a nonprofit organization to promote American Indian history and culture.

What is apparent in this large assembly of work is that the artists, in their own way, are expressing themselves in the media and styles of contemporary European-American art. But often the theme, iconography or title is drawn from Indian traditions. An abstract or collage may bear a title calling forth the tribal spirits of the Indian world.

Scholder, who is represented in the show by a modern acrylic of a traditional figure of a "Standing Warrior," has said that no one needs to worry about the end of "Indian art" despite the movement toward contemporary styles and media.

"The American Indian artist, like everyone else, lives in 1979 and 1980 and must cope with that in his own work," Scholder has said. "If an artist is a full-blood Indian, his world will be full-blood Indian."

In the Smithsonian exhibit are the works of two or three Indian artists who used the brush to make a social statement. "Used and Abused," a mixed-media drawing by Jack Malotte of the Shoshone tribe, presents an Indian in half-figure looking over a barbed-wire fence. He wears modern sun shades and a cowboy hat and sports a slogan button as well as feathers. In the background, bulldozers work on a mesa while a jet streams overhead.

"When Coyote Leaves Reservation," from artist Harry Fonseca, is a serigraph with satiric bite with its animal-headed figure dressed in a black leather suit with dangling chains and a great array of silver zippers. Of course, he also is wearing high-heeled boots.

Some of the American Indian artists still draw images from the past as seen in "Pawnees Breaking Ponies on Platte River," by Brummett Echohawk. And the diversity of the styles and approaches is shown in the work of other artists who have turned to the abstract. One of these is Jaime Quick-to-See Smith (French-Creek-Shoshone), who has contributed a collage, "Red Lake Series No. 70."