As Christmas Day drizzled over downtown Washington yesterday morning, Santa Claus maneuvered his postal truck down Corcoran Street NW and pulled up in front of a small apartment building.

Holding an express mail envelope in his white-gloved hand, he dialed a telephone number on the building intercom.

"This is --- ---," a recording replied. "Please leave your name and number and I'll be back to you."

It was that kind of Christmas for Larry Epps, a Postal Service special delivery messenger who attired himself as Santa Claus to bear mail throughout zip code 20009 on a day when half his intended recipients proved not to be at home.

The Postal Service gets out the mail every day of the year, although only special delivery, express mail and perishables are handled on Christmas. Two dozen special delivery messengers covered the city yesterday; this year, for the first time, eight wore Santa suits on Dec. 24 and 25.

Epps climbed back into his truck, cut through an alley and stopped at 18th Street. A young man in a windbreaker walked by, did a double-take and tapped on the truck window.

"Hey, Santa!"

Epps smiled and waved.

A few blocks away, on R Street, Santa rapped on the green door of a town house decorated with two holly wreaths. Alice Edde answered the door.

"What is this?" she asked. "I can't believe it! Delivery on Christmas Day."

She signed for two packages, which turned out to be merchandise she had ordered for herself. "I'm a catalogue freak," Edde explained.

Next stop was another town house, where Epps handed Robert Otto a package from his children on the West Coast.

"Hard-working guy on a day like today," Otto told Santa.

Like Otto, most customers are very nice, said Epps, 57, a postal carrier for 27 years. There are exceptions.

Once, when he was on the night route in standard-issue postal uniform, a man who didn't believe he was a mail carrier pulled a pistol on him when Epps rang the doorbell.

"He apologized, said, 'I'm sorry, so many people do so many things,' " Epps said. "It doesn't really frighten you at the time. It's only afterward that you think: What if he had shot through the door?"

Zip code 20009, Epps' territory for nearly three years, stretches from the well-kept side streets of northern Dupont Circle through the elegant precincts of Kalorama to the lively blocks of trendy ethnic restaurants and neighborhoods of Adams-Morgan. Being a special delivery messenger is a "preferred assignment" that Epps enjoys for the freedom it gives him to plot his own course rather than be directed by the unyielding path of an assigned route. He was eligible for retirement two years ago, but has hung on, he said, because "I'm not ready yet."

Epps did not work on Christmas Day when his five children were small. His youngest children, twins, are now 17 years old, and Epps planned to celebrate with two dozen relatives at an evening dinner. Thursday night, Epps said, he wore the Santa suit around his South Dakota Avenue neighborhood "and fooled around with the neighborhood kids for a while" before going to church.

"I like to see the reaction on Christmas," he said. "Most people are surprised on Christmas. It brings joy to their faces to have the mail delivered on Christmas Day."

Still, he was not too surprised at the number of no-show recipients he had this Christmas Day. Because Washington has many transient residents, "a lot of people leave -- go home -- for Christmas," Santa said.

Next stop was the Washington Hilton. "Merry Christmas, brother Phillips," Epps called out to R.N. Phillips on security detail outside. He delivered a package to the hotel front desk, then stopped to look at some photos of Phillips done up as Santa Claus for the hotel Christmas party last Saturday.

Into the front driveway of the Altamont at Wyoming and 20th. "Where's your stomach? You're not fat!" said Carolyn Covington, who was doing desk duty on the holiday. She signed for the package Epps dropped off.

"I knew I should have brought my camera," she sighed.

As Epps headed out the front door, she called out: "You gain some weight by next year, you hear?"