By RICK LYMAN

LOS ANGELES, Oct. 22 In a gloomy, concrete labyrinth beneath a storm drain, Dr. Harold Medford stares into the squeaking, screeching tangle of giant baby ants emerging from their enormous eggs. "When man entered the atomic age, he opened a door to a new world," Dr. Medford says, ruefully. "What we'll eventually find in that new world, nobody can predict."

In this climactic scene from "Them!" (1954), the seminal giant-bug movie from the age of post-atomic anxiety, Dr. Medford (played by Edmund Gwenn) becomes the symbolic spokesman for all of the vague unease felt by a prosperous and complacent American public wrapping its mind around the new, terrifying concept of nuclear radiation. That was then, this is now. In the immediate aftermath of the Sept. 11 attacks, when images of exploding towers were still painfully fresh, the story seemed to connect to the nation's cultural consciousness through the big, explosive action movies that had become a staple of summer movie entertainment in the last decade and whose images seemed most closely to mirror the new reality.

But now, in the current state of growing anxiety over anthrax spores carried by mail into offices, exemplified by images of men in biotech suits sweeping public buildings, the images seem to flow from a very different pop-cultural source: the science-fiction horror film. "The horror movie is just sitting there waiting to deal with this," said Robert J. Thompson, a professor of media and popular culture at Syracuse University. "It is one of the most versatile genres out there, a universal solvent of virtually any news issue. And it is now perfectly positioned to cop some serious attitude, to play a role where it's not simply a date movie but going further back, to the 1950's, where you have the horror movie as metaphor."

Some terrors are too difficult to face directly, and so they come in the more easily donned cloak of metaphor. That has been the secret agenda of the horror movie from the beginning, and what has made it one of the most enduring of film genres. How this genre will respond to a new round of anxiety over yet another invisible menace remains to be seen, but it is certain to translate those terrors into something cathartic and ameliorative. "Decade by decade you can see how the horror film has been a way of responding to a number of broad, cultural anxieties," said Eric Freedman, an assistant professor of film and television who teaches a course on horror films at Florida Atlantic University. "It's not unique to this particular historical moment. Action-adventure films and other genres have their own way of responding, but horror tends to do so in a way that taps into some particular threat to individuality, to issues of identity or loss of self, in a way that other genres do not."

Horror has never been at the top of the pecking order among Hollywood genres, always a kind of tolerated stepchild. It is a rare "Sixth Sense" (1999) that emerges as both a box-office and critical favorite. "It's usually something that's directed at the youth market, really a subgenre that we typically don't position up there in terms of cultural importance," Mr. Freedman said. So it is amazing how often, when one looks back, it is through this amazingly resilient genre that cultural anxieties come into sharpest focus.

"The Cabinet of Dr. Caligari" (1919) and "Nosferatu" (1922) helped translate to a shellshocked generation of trench-warfare survivors their inexpressible worries about a social order in turmoil. "Frankenstein" (1931) and "The Invisible Man" (1933) were as much about 20th-century tension over the mystifying rush of scientific progress as they were the original stories upon which they were based. And it can be no coincidence that the first decades forced to come to grips with the insights of psychoanalysis saw not one but three major screen versions of "Dr. Jekyll and Mr. Hyde," featuring John Barrymore (1920), Fredric March (1932) and Spencer Tracy (1941) as Robert Louis Stevenson's tormented protagonist.

But the era that seems to many to fit the current national mood most closely was the early 1950's. Then worries about atomic radiation another invisible killer that could seep into your very bones without your knowing it were translated in pop-culture terms in a series of successful B-grade horror movies that sought to dissipate fears about the future by expressing them in the most exaggerated ways. "One gets the feeling, particularly in the Japanese films but not only there, that a mass trauma exists over the use of nuclear weapons and the possibility of nuclear wars," Susan Sontag wrote in an essay on 1950's science fiction. "Most of the science-fiction films bear witness to this trauma and, in a way, attempt to exorcise it. The accidental awakening of the super-destructive monster, who has slept in the earth since prehistory, is often an obvious metaphor for the Bomb."

The first of the atomic-monster films to be released in the United States was "The Beast From 20,000 Fathoms" (1953), which was about a prehistoric creature released from the Arctic ice by a nuclear test. The next year, however, saw the release of the subgenre's two most enduring examples, "Godzilla, King of the Monsters" and "Them!" Godzilla, like the beast from the original film, emerges from the sea following an atomic explosion and acts as a kind of instrument of divine punishment for man's daring to tamper with such sacred forces. In "Them!," which inspired more than a dozen subsequent giant-insect movies, a colony of irradiated ants grow to the size of recreational vehicles and eventually make their way out of the desert and into unsuspecting Los Angeles.

"When society is trying to deal with the unimaginable, it's interesting how often it is horror films that help them cope with it," said Ernest Dickerson, an acclaimed cinematographer turned director whose first horror film, "Bones," will be released on Wednesday. "How do you survive when an unimaginable force is trying to destroy you? Seeing how people cope with something like that up on the screen helps prepare us somehow. Just as science-fiction films, I think, become a cushion for future shock, horror films become a cushion for terror shock." Giant scorpions attacked in "The Black Scorpion" (1957), huge grasshoppers in "Beginning of the End" (1957), a revived pterodactyl in "Rodan" (1956), a huge lizard in "The Giant Gila Monster" (1959) and a caterpillarlike behemoth that was actually the radiation-mutated larval state of a fly in "The Monster That Challenged the World" (1957).

Even humans were not immune. In "The Atomic Man" (1955), a scientist could see into the future after being blasted by radiation. Sunlight would transform another irradiated scientist into "The Hideous Sun Demon" in 1959. And 1957 saw movies about two men subjected to intense radiation; one grew into the "Amazing Colossal Man" and the other became "The Incredible Shrinking Man." The horror genre has translated national crises into popular entertainment in other ways as well. Many have cited xenophobia or cold- war fears with spawning a cycle of films in the 1950's and 60's about alien attacks and infiltrating monsters from outer space. And fears about AIDS and sexuality have been cited as instigators of the cycle of slasher flicks in the 1980's and 90's, in which promiscuous teenagers found themselves butchered by relentless, faceless, knife-wielding killers.

The main question Hollywood storytellers are asking themselves now is whether the public will want this particular anxiety over threats of terrorism and germ warfare dealt with in some roundabout, metaphoric way, like the giant bugs, or more directly. Hollywood has already dealt with the issue directly, in at least two major films that tapped into anxieties about the hidden horrors of microscopic killers. Robert Wise's "Andromeda Strain" (1971), based on the Michael Crichton thriller, was about microbes from outer space. And Wolfgang Petersen's "Outbreak" (1995) was about high-tech scientists racing to control an escape of a plaguelike virus. Both of them, though, fell more into the realistic, science-fiction thriller genre than the horror category.

"I think people might be approaching it more directly this time than they did back in the 1950's," the film producer Andrew Lazar said. " I think we'll see stories more reality based than the movies of the 50's, taking real things and making a real, tight thriller out of it. The movies and the audience are just more sophisticated than they were." But others believe that the need will persist for some sort of metaphoric approach that does not force audiences especially young audiences to face their anxieties directly. After the post-atomic films ran their course in the 1950's and early 60's, the horror genre turned inward. The monsters became much more personalized and invasive, and the violence more graphic. In the "Nightmare on Elm Street" series, the razor-taloned villain Freddy Krueger emerged from the protagonists' own dreams. And in "Halloween," the 1978 John Carpenter thriller that in many ways presaged the horror films of the next two decades, the deranged and relentless villain was Michael Myers, a mental patient who had been abused as a youth.

"I think what's going to happen to the horror film now is that it's going to become less a genre of personal psychological failure, like the Michael Myers character in the `Halloween' movies, where it's all about internal psychoses or the psychological damage of someone who comes back to haunt us, and become much more a genre about a wider threat," Mr. Thompson said. It might not be giant bugs, but some sort of shape will be found to symbolize today's faceless villain.

"The horror movie is going to move away from the age of Godzilla, which personified this enormous threat of atomic power to destroy things, and it's going to move away from Michael Myers and fears about adolescents being messed up by the corruption in our culture," Mr. Thompson said. "Instead, it's going to be much more on the `X-Files' model, where the villain is elusive and perhaps conspiratorial. "The big danger will be not so much what these monsters are capable of doing as their fundamental elusiveness. But it's going to take some doing to write these things because, you know, you have to have an ending."