022 Isaac Casaubon

As of August 21, 2023, the entry for the sixteenth century scholar (and namesake of a famous character in Eliot's Middlemarch) Isaac Casaubon does not yet mention—in the "Literary Appearances" section—that he is discussed at length in Nicholson Baker's novel Room Temperature. 

021 Et in Arcadia Ego

 As of December 9, 2021, the entry for the painting "Et in Arcadio Ego" includes a section on literary and pop cultural references to the title phrase, but it does not yet mention the fact that Vladimir Nabokov references it in his novel Pale Fire. See p. 237 of the Vintage International edition.

020 George Dandin

As of December 12, 2019, the Wikipedia entry for the Molière comedy George Dandin ou le Mari confondu does not yet mention that it is the origin of a well-known conventional phrase or tag, tu l'as voulu, George Dandin (lit. "you have wanted it, George Dandin," and used in the sense of "you have brought it on yourself"). The phrase appears in Saul Bellow's The Adventures of Augie March, Fyodor Dostoevsky's The Idiot, and other works.

019 Leo Africanus

As of Sunday, September 15, 2019, the entry for the Renaissance-era traveler and geographer Leo Africanus does not yet mention what is perhaps his most famous posthumous activity -- namely, that of appearing as a spirit guide and daemon companion to the poet W.B. Yeats, in his various spiritualist explorations. See Richard Ellmann's study, Yeats: The Man and the Masks.

018 Swan Lake

As of Thursday, August 22, the Wikipedia entry for Tchaikovsky's "Swan Lake" lists several songs that have borrowed heavily from the ballet's music -- but it does not yet list the Khmer song "The Story of My Love" by Chhuon Malay, which is featured in the soundtrack of the 2015 documentary Don't Thing I've Forgotten. Go and have a listen - it's totally the act II theme from "Swan Lake." And it's awesome!!

017 Krusty Gets Kancelled

The entry on the 1993 episode of The Simpsons (penned by that great lover of old-times Americana John Swartzwelder) "Krusty Gets Kancelled" mentions a number of cultural allusions contained in the show. It does not yet mention, however, perhaps the most important pop cultural reference in this tale of Gabbo, the demented ventriloquist's dummy: the allusion to the urban legend about "Uncle Don's" notorious blooper (which never actually happened). The entry on A Face in the Crowd ought to mention the debt the film owes to the Uncle Don story as well.

016 The Barefoot Boy

The article on the John Greenleaf Whittier poem "The Barefoot Boy" does not yet mention that the poem is referenced by Mr. Burns in an episode of The Simpsons. He says: "I was once a barefoot boy with cheek of tan," quoting the poem. He is speaking at this moment to Snappy the Alligator, held by Mr. Smithers.

015 Assegai

The entry on the Zulu weapon an assegai does not mention that a character is named after this implement in Lorraine Hansberry's A Raisin in the Sun. 

014 Trophonius

The entry on the chthonic deity Trophonius might mention another literary reference thereto: in Nicholson Baker's 1988 novel, The Mezzanine, the author described the imagined inner workings of an escalator to be "Trophonian."

013 Trapdoor

We all recognize the image: the evil boss/magnate has a trapdoor in front of his desk, through which he can drop employees and labor agitators and anyone else at his diabolical pleasure. Mr. Burns has one, for instance. But where on earth did this come from? Who originated the trope? Perhaps some earlier instance could be found, but he's one I'd put forward as a possible contender: F. Scott Fitzgerald's unfinished Hollywood novel, The Last Tycoon. Our narrator Cecilia's father (the crude and scheming arriviste, not the brilliant Monroe Stahr who is the tycoon of the book's title) is rumored to have set up such a device. "I've heard a story about a trap door in the floor that would drop unpleasant visitors to an oubliette below but believe it to be an invention," says Cecilia. Probably the trope is older -- showing up in some work of pulp fiction or other. But who knows -- maybe Fitzgerald came up with it. And currently, let it be known, its appearance in Fitzgerald is mentioned neither in the Wikipedia nor the TV Tropes articles on the subject of trapdoors.

012 Prisoner of Chillon

As of December 26, 2018, the page for Byron's poem "The Prisoner of Chillon" does not yet mention the fact that there is an indirect allusion to it in Henry James's Daisy Miller (Miller and our protagonist Winterbourne visit the castle of Chillon in Geneva, and Winterbourne recounts the fate of Bonivard. Further evidence is provided later in the story that he is a Byron fan -- he recites aloud to himself (people are always doing this sort of thing in old novels) several lines from "Manfred" while waiting alone in the Colosseum at night. Perhaps all this is intended as an ironic commentary on the fact that Daisy Miller will be subjected to the same kind of fanatical persecution and ostracism that Byron's prisoner undergoes.)

011 Victor Cherbuliez

As of December 26, 2018, the page for 19th century French novelist Victor Cherbuliez does not yet mention his novel Paule Méré, despite the fact that there is an intriguing allusion to it in Henry James' Daisy Miller, which draws an oblique parallel between the persecution of Cherbuliez's heroine and that of James's.

010 McLean Hospital

It's that famous hospital for wealthy Boston brahmins and literary types who have gone a little haywire in the head ("thoroughbred mental cases," as one of their number, Robert Lowell, once put it). But one of its former patients (fictional, in this case, but no less blue-blooded) who is not yet mentioned on the Wikipedia page (as of December 8, 2018) is Polly Perkins, from the great 1990 Whit Stillman film Metropolitan. Perkins is doubly fictional in this case, as she is made up by one of the characters (no, not made up, a "composite," he insists, "like they do in New York Magazine"), but in any case it is clearly stated that she -- addled debutante that she is -- did time in McLean.

009 Notes of a Son and Brother

As of November 19, 2018, the entry for the Henry James autobiography Notes of a Son and Brother mentions the childhood accident that caused "the obscure hurt" that haunted James throughout his life, but it does not include the passage from Hemingway's The Sun Also Rises that alludes to the incident, using it as an oblique way of referencing the protagonist Jake Barnes' war injury that has left him unable to have sex. This is the passage about "Henry's bicycle," and which is almost certainly a reference to the "obscure hurt."

008 One of Ours

As of November 19, 2018, the entry for Willa Cather's 1923 novel One of Ours mentions that Hemingway once deprecated the realism of its war scenes in a letter to Edmund Wilson, saying that Cather had lifted these sequences from Birth of a Nation. It does not add, however, that Hemingway included the same observation in his first published "novel" -- the forgettable heavy-handed parody of Sherwood Anderson The Torrents of Spring: "Like this American writer Willa Cather," the passage reads, "who wrote a book about the war where all the last part of it was taken from the action in Birth of a Nation."

007 Running Water (novel)

As of November 18, 2018, the entry for the 1906 adventure novel by A.E.W. Mason Running Water does not mention that it is almost certainly (given its plot) the intended referent in the following passage from Hemingway's The Sun Also Rises: "The book was something by A.E.W. Mason, and I was reading a wonderful story about a man who had been frozen in the Alps and then fallen into a glacier and disappeared [...]" etc.

006 Cupid (Sam Cooke song)

As of November 17, 2018, the entry for the song "Cupid" by the great Sam Cooke does not mention that Bon Jovi's 2005 song "Who Says You Can't Go Home" kinda stole the melody to the chorus. But it would seem the similarity has been noticed before. And the parallels are pretty obvious once you start to notice them. There's the shared trochaic opening, on the same two notes: (Cúpid/Whó says). And a similar end to the line. Ho-o-ome. Bo-o-ow. Still a catchy song, Bon Jovi. I like it a lot. But I might mostly just like it because I like Sam Cooke a lot.

005 Colors Insulting to Nature

As of Saturday, November 17, 2018, the entry for Cintra Wilson's novel Colors Insulting to Nature makes no mention of the fact that the book's cover art was created by American artist Wayne White, painter of snarky prose phrases in pastel block letters superimposed with comic incongruity over bucolic landscape scenes (his cover of the Wilson novel is a fine example of the style). Wayne was also artistic director on Pee-Wee's Playhouse, whatever we are to make of that.

Intriguingly, both Wilson and White came to my attention through the same recent episode of the Omnibus Project (the Ken Jennings/John Roderick podcast), but through an indirect connection. This episode ("Wild Man Fischer") mentioned a book by Carl Wilson (no relation, to my knowledge) about Céline Dion, as well as a Wayne White painting that Ken had recently acquired. It was in the Carl Wilson book that I encountered a reference to a different work by Cintra Wilson, which led to Colors Insulting to Nature, and back to Wayne White again.

004 Lottery paradox

At least as of August 15, 2018, the Wikipedia entry on Henry Kyburg's The Lottery Paradox does not yet mention that a restatement of this paradox appears in Andrew Crumey's 1996 novel D'Alembert's Principle. 

https://en.wikipedia.org/wiki/Lottery_paradox

In Crumey's novel, it is attributed to a fictional philosopher of the Scottish Enlightenment -- one Magnus Ferguson -- who seeks to defeat D'Alembert's vision of an ordered and rational universe by reducing reality to the principles of chance and probability.

I find the statement of the paradox in the novel, by the way, more compelling and more obviously paradoxical than the Wikipedia description. To paraphrase from Crumey: imagine two scenarios: 1) a winning ticket is included in a thousand-ticket lottery; 2) a die is cast such that the number of possible outcomes is 1,000, and a gambler bets on one of these outcomes. In both scenarios, a participant in the game would have a 1/1000 chance of success. Yet -- scenario (1) guarantees a winner. Scenario (2) does not. So shouldn't the odds be better in scenario (1)?

003 Jeanne Julie Éléonore de Lespinasse

At least as of August 15, 2018, the Wikipedia entry on French Enlightenment salonnière Jeanne Julie Éléonore de Lespinasse does not include -- among its list of fictional treatments -- her extended appearance in Andrew Crumey's 1996 novel D'Alembert's Principle. 

https://en.wikipedia.org/wiki/Jeanne_Julie_Éléonore_de_Lespinasse#Publications

However, I do have to credit the comprehensiveness of the Wikipedia editors with this: Crumey's novel does appear on the D'Alembert page.