It didn't look like a particularly romantic film, but the three chemists assured the audience of slightly bewildered reporters it really was pretty racy. Did you see, they asked, that little gray moth twisting and fluttering and flashing what they called his "hair pencils"? Well, he was "nearly hysterical" because he couldn't seem to get a certain female gray moth to pay attention to him. Of course, the chemists said, it wasn't surprising the male was frustrated, since the female moth was currently in the process of mating with another male.

This was the week 13,019 chemists came to town, bringing with them tales of excitement, glory and bugs.

"We're going to tell a story that involves insect pheromones, plant scents and human perfumes," said W.L. Roelofs, of the New York State Agricultural Experiment Station, at the beginning of a press conference at the American Chemical Society. In more familiar terms, his was a tale of courtship, romance, sex, frustration and lemon tea.

It seems the male oriental fruit moth is first drawn to a female by a pheromone, a chemical that attracts him over a long distance. When he reaches the female, he lures her to him with his own perfume, which includes scents similar to cinnamon and jasmine. He then flares those hair pencils, sprays his intended with a blast of scent, figures out where her head is, goes for the other end and, as Roelofs put it, "whirls around and BAM! More insects."

Quite a story. And that's not even the exciting part, but for the bit about the lemon tea, it's probably as much as the layman could understand. The lemon tea enters the chemical picture because one of Roelofs' fellow chemists realized the male scent reminded him of the smell given off by Japanese tea with a slice of lemon. He isolated the scent and found it to be a form of methyl jasmonate, which the perfume industry uses in floral perfumes.

The inevitable question was finally asked.

"It acts as an aphrodisiac for moths. Any connection with humans?"

The chemists laughed and looked a little embarrassed. One ventured to answer.

"No comment," he said.

A chemist is always prepared. This group arrived with calculators, test tubes and stamp collection in tow.

Stamp collection?

Some very serious chemical things were happening around the city as the society gathered for its 186th meeting, but that didn't mean no one could have fun. A special exhibit at the Convention Center called "Chemistry in Philately" was the surprise hit of the meeting, which continues through tomorrow. Some playful meeting organizer labeled the press briefings things like "Why Kidneys Don't Rust" and "Courting with Cologne--a Male Moth Lures His Love."

"Colorful. Educational."

That's how one sign at the Chemistry in Philately exhibit described stamps and trading cards devoted to scientific subjects. Some facts: Marie Curie is the scientist most widely honored in stamps, with approximately 100 commemorative editions issued. Paul Muni played Louis Pasteur in the movies.

"Russia is the most notorious," said Foil A. Miller, a chemist-philatelist from Pittsburgh. "They have the most stamps with chemists and scientists. But they're printing stamps to sell," he continued, with a scientist's disgust for excess. "They'll put out an unduly large number, so they end up scraping the bottom of the barrel for subject matter."

In the midst of the nearly 40 other exhibits, 35 scientific trading cards collected by Howard University's Martin Feldman provided more surprising information. Churchman's Cigarettes released a card in 1929 with an outmoded model of an atom's composition. Topps Gum's 1962 "Gee Whiz Quiz" asked questions like "What is the brightest star in the sky?" And in 1953 a card in Topps' "Look-N-See" series claimed that the ubiquitous Marie Curie wrote her lab notes in the margin of her cookbook.

And, as one exhibitor with a wondrous mastery of alliteration wrote, "There is Pride of Profession in Vivid Vignettes of the History of Chemistry from Alchemists to Atoms."

With his wide smile, shiny skull and crinkly eyes, Linus Pauling looks remarkably like George Lucas' Yoda, and the several hundred chemists who came to hear him speak on Tuesday seemed to expect he would entertain them with a charming, Muppet-like quirkiness. They were not disappointed.

"The references of the last two speakers to hemoglobin was just too much for me," he began, "so I'll say something about it." Pauling, who has won Nobel Prizes in chemistry and peace, then launched into a mini-lecture on his hemoglobin research. Although it went on for several minutes, the audience, which had come to hear about the social and political responsibilities of the scientist, didn't seem at all surprised. This was Linus Pauling, after all.

Pauling finally digressed from his digression. "I'm stuck," he said, "because I promised to talk about something else. I'll try to stick to the subject, but if I wander off to chemical studies, you'll forgive me."

For the next 40 minutes Pauling, who will receive the chemical society's Priestley Medal next spring, rhapsodized on the career of Joseph Priestley, the 18th-century scientist who discovered oxygen. He sprinkled his talk with references to President Reagan, nuclear armaments and his own Unitarianism, as well as an anecdote about his early scientific exploration that made you pity his mother.

"I might mention something that happened to me when I was 14 years old," he began. "I was doing an experiment that involved a five-liter bottle of concentrated sulfuric acid, and while I was putting the bottle back on the shelf, I broke it against the concrete wall. After I took off my clothes and shook them out, I started to sweep the sulfuric acid to a drain in the floor. Well, nothing happened, except the broom turned black. But when I put the hose on to wash it down the drain, it all began to effervesce. I didn't understand this, but later when I learned about ionization it gave me a great interest in theory."

Do chemists have a sense of humor?

"For the most part," said the woman behind the T-shirt stand at the Convention Center. "People stand here and laugh at these, especially the bumper stickers."

They were laughing at:

* A canvas bag and matching apron emblazoned with the message "Experiment with a Chemist."

* T-shirts with the logos: Chemists React Faster; Chemistry Spoken Here; I Have Designer Genes; Chemists Live Life in the Flask Lane.

* Bumper stickers that said: Old chemists never die--they just reach equilibrium; It takes Alkynes to make a world; It's amino world without chemists.

" 'Experiment with a Chemist' sells the best," the woman said.