This is a story of two homecomings, two very separate weekends -- but both full, all the same, of mixers and Greeks, bonfires and beer, nostalgia and baccanalia. These are two weekends that shared, too, the homecoming's function as a psychic yardstick: a measure of the changing present against a changeless past.

One story is about Bob Davis, retired veterinarian and begonia raiser. He used to make chicken vaccines. The other is about Jim Henson, Muppet man, the multimillionaire creator of Kermit the Frog.

For Davis, it was the 50th consecutive University of Maryland homecoming; for Henson, the first in 19 years.

"This whole campus has Muppet fever," says Jordan Fox, president of the Maryland Student Government Association.

Fox, is right. Kermit the Frog -- in chicken wire, tissue paper or hanging from fraternity windows -- is e verywhere. This is the year that Maryland's most famous son, the bearded, slender Henson, is coming back.

"The University of Maryland isn't exactly well-known for its alumni," says Fox. "Except for an athlete here and a convicted criminal there."

Henson, 42, who now lives in New York and London, grew up in nearby Hyattsville. Kermit, the smug and charming regular of "the Muppet Show," which appears in 106 countries, did too.

In fact, Kermit was 3 years old when Henson graduated in 1960. Even then he was bringing in enough money to allow his human father to attend graduation in a rented, but nonetheless authentic, Rolls-Royce.

The parade begins Friday at dark, in a pouring rain. The tissue-paper Kermits get soggy. So does Davis, 72, who watches the Kermits and Kappa Kappa Gammas parade by from the sidewalk in front of the administration building.

But Davis, who isn't even a Maryland alum, refuses to let a little rain get in his way. After all, he's survived every Maryland home game since 1930, when he came from Alabama cotton country to do veterinary science research at Maryland.

"I went to a few games that only crazy people would go to because of the weather," he says. "Somewhere between 1940 and '45," he remembers, "the weather responded to one of the so-called hurricanes very well. I remember when Maryland punted the ball, and the wind caught it, and it hit the ground behind the team. There were about 25 people in the stadium."

Davis has on a tie, windbreaker, glasses and a slight gray stubble. He used to raise chrysanthemums before the begonias, and was once mayor of College Park. Most people wouldn't notice him on a bus.

Henson, perhaps because he lives in London, looks a little European -- a flowered shirt and paisley tie, a brown corduroy suit. He stands on some steps above the sidewalk, under an umbrella and lights with the rest of the parade judges. The Sorority Reception

"Mr. Henson, Mr. Henson, they want you over here," cries an Alpha Xi Delta sorority member. Over there are about 15 sisters, standing in a formal grouping on the stairs.

Henson, goes over, takes his place, and pop, flash, flash. "This is a little silly," he admits between signing autographs that say "Kermit the Frog." It's funny, because in London I'm never recognized on the street."

The reception after the parade is held at AXD because Henson's wife, Jane, whom he met in a puppetry class at Maryland, is an alumna. At the reception, she is given five pink roses and a gold plaque naming her the Rose Girl of 1979.

Henson, meanwhile, tackles the fans.A lot of them giggle.

"At what age did you discover your creative talent?" asks a young reporter.

Henson, looking harassed, mumbles something.

"We all watch the Muppets together," says a sorority member. They're so cute."

More flashes.

"You know," says Agnes Jenkins, Henson's aunt, who is on hand for the occasion, "there are almost as many cameras in here as people."

Finally, Henson is asked if he has any special feeling for Maryland. What did the university experience mean for him?

"That's not an easy question to answer," he says. "I'd just as soon skip that."

Around the corner is 7306 Princeton Ave., a small brick house that belongs to Davis. He's in a quiet, cluttered study with plastic plants, pictures of the kids and his wife, Alma. Both are watching television.

"I just do it, that's all," he says, explaining his unbroken attendance at 50 homecomings. "I knew all along I hadn't missed any, but I didn't think much about it until I hit number 35. I guess I just like football." The Breakfast

"At the end of this season," says Patty Jantho, a bubbly, camp-director sort who runs Maryland's alumni emeritus program, "Dr. Davis will have attended home games for 50 years." It is Saturday morning, and everybody, which is about 25 alums who graduated 50 or more years ago, applauds in the black-and-red Tortuga Room of the Student Union.

"Well," says Davis, "I feel quite honored to be recognized today along with Mr. Muppet."

Then, over coffee and pastries, Jantho makes everybody play a cnversation game.What this means is that alums have to switch tables when she says so and talk about written questions like "What was your most amusing campus experience?" and so on.

At Davis' table, the talk runs from home economics to basketball to the weather. "Have you ever heard so many old-timer stories in your whole life?" he asks when it's over.

Henson, who won't be emeritus until the year 2010, isn't invited. The Awards Ceremony$.t"Kermit is our middle-class everyman in green drag," says Robert Gluckstern, chancellor of the College Park campus. "Every age needs its heroes -- even ours, which some have called the age of antiheroes. This weekend, we celebrate the return of our Homer."

And with that, Henson and Kermit are introduced to some 200 in Hoff Theatre, just prior to the game on Saturday. Davis is in the audience with his wife to watch Henson receive the 1979 Distinguished Alumnus Award.

"Hi there," says Kermit, who is on Henson's arm. "I was watching the parade last night and it was wonderful to see us all immortalizd in chicken wire."

Kermit, who is decidely funnier than Henson (who operates him), then apologizes for the absence of Miss Piggy, a fellow Muppet.

"Miss Piggy," says Kermit, "heard that they were kicking around a pigskin and all that stuff, and combined with the fact that all those people were eating hot dogs, well, she thought the whole thing was sort of barbaric."

And from Henson: "It's a neat feeling to go to school here, to be one of 10,000 kids and to come back and be treated like the president of the school."

Henson and Kermit get a standing ovation. Midway back in the audience, Davis says the frog is "very cute." The Game

Davis sits in Sec. 4. Row UU, Seat 25. Maryland plays North Carolina, and when the sun goes away, it is cold, cold, cold. But Davis doesn't notice because he is hunkered over, feet spread intently watching every move the Maryland Terps make.

His only comment is an occasional grunt, which comes out as "humpf.' Every once in a while he'll talk, but not much. This usually takes the form of "punt it."

Henson sits across the stadium in the president's box. It is warm, glass-enclosed, carpeted with a maroon rug, and holds university president John Toll and Labor Secretary Ray Marshall, on hand as a guest.

"I'm an ardent fan," says Henson, who says he hasn't been to a game since he graduated. He takes pictures of the box guests with his Pentax and talks to Mrs. Toll.

North Carolina blows a pass in the final seconds of the game and Maryland wins, 17-14. Davis, across the field, is ecstatic.

Laughing, he heads for the Terrapin Club, the boosters' drinking hangout, for bourbon and ginger. "We won the game," says Davis, when asked if his 50th was anything special. "That's the special part."

Henson, meanwhile, is nowhere to be seen. He has to get to a family reunion, and makes a fast exit.