Dr. Curran proposed a scientific study. He collected as many caterpillars as he could in a day, determined the average number of reddish-brown segments, and forecast the coming winter weather through a reporter friend at The New York Herald Tribune. His experiment, which he continued over the next eight years, attempted to prove scientifically a weather rule of thumb that was as old as the hills around Bear Mountain. The resulting publicity made the woolly bear the most famous and most recognizable caterpillar in North America.

The caterpillar Curran studied, the true woolly bear, is the larval form of Pyrrharctia isabella, the Isabella tiger moth. This medium-size moth, with yellowish-orange and cream-colored wings spotted with black, is common from northern Mexico throughout the United States and across the southern third of Canada. As moths go, the Isabella isn't much to look at compared with some of the other 11,000 species of North American moths, but its immature larva, called the black-ended bear or the woolly bear (and, throughout the South, woolly worm) is one of the few caterpillars most people can identify by name.

Woolly bears do not actually feel much like wool -- they are covered with short, stiff bristles of hair. In field guides, they're found among the "bristled" species, which include the all-yellow salt marsh caterpillar and several species in the tiger moth family. Doug Ferguson, an entomologist at the National Museum of Natural History in Washington, D.C., says, "I've heard people call different caterpillars 'woolly bears,' even ones that are all black, all brown, yellow, or gray. It's the hairiness they're referring to. I guess you'd better be careful about which caterpillar you're looking at before you make your prediction."

Woolly bears, like other caterpillars, hatch during warm weather from eggs laid by a female moth. After feeding on dandelions, asters, birches, clovers, maples, weeds, and other vegetation, mature woolly bears disperse and search for overwintering sites under bark or inside cavities of rocks or logs. (That's why you see so many of them crossing roads and sidewalks in the fall.) When spring arrives, woolly bears spin fuzzy cocoons and transform inside them into full-grown moths.

Typically, the bands at the ends of the caterpillar are black, and the one in the middle is brown or orange, giving the woolly bear its distinctive striped appearance. According to legend, the wider that middle brown section is (i.e., the more brown segments there are), the milder the coming winter will be. Conversely, a narrow brown band is said to predict a harsh winter.

Between 1948 and 1956, Dr. Curran's average brown-segment counts ranged from 5.3 to 5.6 out of the 13-segment total, meaning that the brown band took up more than a third of the woolly bear's body. As those relatively high numbers suggested, the corresponding winters were milder than average. But Curran was under no scientific illusion: He knew that his data samples were small. Although the experiments popularized and, to some people, legitimized folklore, they were simply an excuse for having fun. Curran, his wife, and their group of friends, who called themselves The Original Society of the Friends of the Woolly Bear, escaped New York each fall for the glorious foliage and the meals at the posh Bear Mountain Inn. The naturalist Richard Pough was a member, as was Kim Hunter, the actress who starred in the movie Planet of the Apes.

Thirty years after the last meeting of Curran's society, the woolly bear brown-segment counts and winter forecasts were resurrected by the nature museum at Bear Mountain State Park. The annual counts have continued, more or less tongue in cheek, since then. This fall, museum director Jack Focht will gather a dozen or so caterpillars, as he has done since 1988, and spread them out on the kitchen table of his "folklore consultant," Clarence Conkling. The two men will count the brown segments, average them, and declare another forecast from Woolly Bear Mountain. "We're about 80 percent accurate," he says.

For the past ten years, Banner Elk, North Carolina, has held an annual "Woolly Worm Festival" each October, highlighted by a caterpillar race. Retired mayor Charles Von Canon inspects the champion woolly bear and announces his winter forecast. His method differs from the more common number-of-brown-segments method. Counting each of the 13 segments as a week of winter, Von Canon correlates the black segments at the front and rear of the caterpillar with the beginning and end of winter. The more black segments, the worse the winter, and vice versa, with the harshest weather occurring during the black-segment weeks. His predictions, locally famous, are said to be 70 percent accurate.

But most scientists discount the folklore of woolly bear predictions as just that, folklore. Says Ferguson from his office in Washington, "I've never taken the notion very seriously. You'd have to look at an awful lot of caterpillars in one place over a great many years in order to say there's something to it." Randy Morgan, from the insectarium at the Cincinnati Zoo, declares, "In my opinion, woolly bears and other so-called weather indicators -- how thick the corn husks are, how high above the ground wasps build their nests -- are simply myths."

Mike Peters, an entomologist at the University of Massachusetts, doesn't disagree, but he says there could, in fact, be a link between winter severity and the brown band of a woolly bear caterpillar. "There's evidence," he says, "that the number of brown hairs has to do with the age of the caterpillar -- in other words, how late it got going in the spring. The [band] does say something about a heavy winter or an early spring. The only thing is . . . it's telling you about the previous year."