The scientific illustrators - whose works are now on view at the Meseum of Natural History - remind us that there are many paths to art. Theirs is straight and narrow.

They don't let it all hang out. Instead, they trust fastidiousness more than freedom, rigorous precision more than self-expression. They aim for accuracy, not beauty, but a special sort of beauty is often hit.

That technology fights beauty, that art and science are at war, is a modern misconception. As were Leornardo, Durer, and Audubon before them, there artists - let us call them that - are scientists as well. (See SCIENCE, B13, Col. 3>

The two were onece thought one. "Review for yourself the history of art," Englishman John Ruskin wrote in 1859, before the heyday of abstraction, "and you will find this to be a manifest certainly, that no great school ever yet existed which had no for primal aim the representation of some natural fact as truly as possible." Truthful representation of the facts of nature is the purpose of this show.

But the natural is often messy. To see the network of the veins, one has to peer through blood. To truly see the patterns formed by the branches of a tree, one has to strip its leaves. The artists represented here are clarifiers, orderers, censors of the messy. They make sense of chaos. No camera can photograph the order that they see.

"The camera is never going to put us out of business," says one of the illustrators in the show, George Venable. That is, perhaps, ironic. The more biology depends on computers, electronics, and other high technologies, the more it must rely, to communicate its findings, on artists and their art.

The artists who draw insects - for instance the Smithsonian Institution's Vichai Malikul, whose field is mosquitos - don't portray individuals; instead, they show us species. The same holds for Anthony Tyznik of the Morton Arboretum, whose meticulous ink drawing represents not only one, but all Downy Hawthorn trees.

Like architects who give us sections, plans and elevations, the artists in this show rely on visual conventions. The insects in the exhibition are shown in lateral, or dorsal, or sometimes head-on view. Tyznik's Downy Hawthorn tree has branches one can measure. But while architects portray windows, bricks and doorways, there illustrators must make sense of such organs as antennae, which bend and swell and swoop.

These drawings have within them an intellectual geometry. It is the way they match strict measurement to the organic that gives this focused show its beauty and its punch.

Some familiar sorts of scientific illustration - bird pictures, for instance, or wild flower stuides, or portraits of, say, wolves - have subjects that allow them to penetrate the galleries, and our living rooms as well.

But because the public is more partial to sweet-smelling blossoms, or sweet-singing songbirds, than it is to buzzing insects, the art of Vichai Malikul is less often seen - except in shows like this one and in such publicatons as "Mosquite Systematics."

Malikul has been drawing mosquitos, ad mosquito parts, for the past 10 years. Of the drawings in this exhibition, none is finer than his.

His colleagues in his field - it is admittedly not large - appreciate the artist. In 1973, when Dr. Yiau-Ming Huang found near Chiangmai, Thailand, a new species of mosquito, he named it Aedes (Stegomyia) malikuli in honor of Vichai Malikul.

Artists in cartoons wear flowing smocks and berets; they stand before large easels in garrets with north light. Malikul's studio in the Museum of Natural History is perhaps 50 yards from the rotunda gallery where the show is on display. It is a small room without windows, furnished with a desk.

Malikul works here - with a box of specimens, a stereoscopic microscope, and the finest brushes he can buy. (They have but a few hairs; their grade is 0000.) It was sitting at this desk that Malikul spent months finishing the drawing included in the show.

If you peer into his microscope, at the insect on a pin, you can see but a small part of it, a leg, say, or a head. The rest is out of focus. Yet the drawing in the show has the clarity and presence of an emblem or a sign.

Dead mosquitos are most delicate, and those the artist protrays often have lost a leg, perhaps a wing. But Malikul knows mosquitos. In his native Thailand, reports the magazine "Mosquito Systematics," he "collected them in biting collections and light traps, learned mosquito rearing techniques and adult pinning procedure." Also, he can draw.

The insect in his ink-and-watercolor drawing has fine transparent wings. One can see right through them. Its abdomen is gleaming with a metallic purple sheen. The hairs of its antennae are as fine as yours, and though many of his colleagues rely on tracings and on pens, Malikul drew those slender curving lines with a hand-held brush. Magnified by microscope, mosquitoes can be beautiful. But they are not more striking than the measured, flattened, accurate drawing in the show.

Like the other 67 artists represented in this exhibition, Malikul is a member of the Guild of Natural Science Illustrators, which are formed here a decade ago as an informal luncheon group for Smithsonian artists and now has 400 members. This was an open show. Each member who submitted work has a drawing on display.

The show is accurately - but too coyly - titled "Perfectly Beautiful: Art in Science." It will remain on view, in the gallery above the largest elephant in the world, until May 14.