The latest Team Cul de Sac donation: “The Searleing of Richard Thompson, or the Blessing of the Heir.” (NICK GALIFIANAKIS / courtesy of Team Cul de Sac)

BACK IN MARCH AND APRIL, when Comic Riffs interviewed Nick Galifianakis about his India-ink-stained colleague Richard Thompson, we wondered what sort of art donation the cartoonist for the Carolyn Hax column might make to his dear friend’s Team Cul de Sac campaign.

Late last night, we got our glorious answer.

Galifianakis and Thompson have been pals of the pen for more than two decades, and they well know each other’s artistic heroes and influences (including Watterson and Oliphant as well as the godhead Searle, from whom a prized original hangs in Thompson’s home).

Today, in his fine line, you can see the degree to which Galifianakis has crafted his original art with care and thought and depth of fraternal feeling.

“There are very few geniuses in the world,” Galifianakis tells Comic Riffs. “The rest of us can aspire only to recognize one, and I’ve had the rare privilege of doing so in my longtime friend.

“For 25 years, I have been in Richard Thompson’s studio to witness his evolution, from lavish pencil drawings to rich oil caricatures through to his brilliant comic strip.”

Thompson — whose strip was born in The Washington Post Magazine — launched the Team Cul de Sac publishing and auction campaign in January as a way to raise funds for Parkinson’s research.

The full back-story is that Thompson learned he had Parkinson’s several years ago only after Galifianakis noticed physical changes in his pal and arranged for the “Cul de Sac” creator to be examined by Galifianakis’s specialist friend.

From the heart of his art, Galifianakis — again — delivers.

THE POST MAGAZINE PROFILE: “Cul de Sac” creator perseveres gracefully despite the ails of his body and industry

PHOTO GALLERY: The work and home of Richard Thompson

BILL WATTERSON: First new public art from “Calvin and Hobbes” creator in nearly 16 years

“It’s not my intention to diminish other talented and important cartoonists, though contemporary greats already agree that Thompson’s work merits special distinction,” Galifianakis wrote in submitting his Team Cul de Sac donation. “As such my illustration depicts the acknowledgment of his place in the history of what we do: Surrounded by a pantheon of cartoonist gods, Searle blesses his heir.”

In May, Thompson was honored by his professional colleagues, as the National Cartoonists Society gave him the Reuben Award.

“Of course, there are giants of cartooning missing,” Galifianakis continues. “Where are MacNelly and Nast? Trudeau, Breathed, Chast or Trondheim? The virtuoso, Chuck Jones? They’re all there, and many others, represented by the anonymous cherub clinging to the master’s shoulder.

“And so the mantle passes from Searle to Thompson ... my grandiose tribute to the humblest of men.”