Я был и в аду, каким представляется Сахалин, и в раю, т. е. на острове Цейлоне. Какие бабочки, букашки, какие мушки, таракашки!

"What butterflies, what small insects! [in Ceylon]"

Chekhov quotes Krylov's fable Lyubopytnyi ("The Sightseer," 1814), not Pushkin's poem The Collection of Insects (as I wrote in one of my previous posts):

Какие бабочки, букашки,
Козявки, мушки, таракашки!*

In a letter of September 11, 1890, to Suvorin Chekhov, sailing from the north part of Sakhalin to the island's south extremity, quotes the punch line of this fable, slona-to ya i ne primetil ("I did not notice the elephant"): "Now that I have done with the convict system, I have the feeling that I have seen everything but have missed the elephant." Slon is Russian for "elephant." On the other hand, SLON (Solovetskiy Lager' Osobogo Naznacheniya) was a particularly cruel force labor camp in Solovki (the Solovetsky Islands in the White Sea). In 1929 Chekhov's friend Gorky visited SLON and wrote a favorable essay, praising the camp's administration and rules. Indeed, he had not noticed the elephant!

La pauvre et noble enfant brings to mind Coppée's poem quoted by Demon:

'Irène de Grandfief, la pauvre et noble enfant

Ferma son pi-ano... vendit son éléphant.' (1.38)

(The elephant is Demon's contribution.)

As he speaks of mysterious Terra, Van mentions the Yakima jailers:

Moreover, although reference works existed on library shelves in available, and redundant, profusion, no direct access could be obtained to the banned, or burned, books of the three cosmologists, Xertigny, Yates and Zotov (pen names), who had recklessly started the whole business half a century earlier, causing, and endorsing, panic, demency and execrable romanchiks. All three scientists had vanished now: X had committed suicide; Y had been kidnapped by a laundryman and transported to Tartary; and Z, a ruddy, white-whiskered old sport, was driving his Yakima jailers crazy by means of incomprehensible crepitations, ceaseless invention of invisible inks, chameleonizations, nerve signals, spirals of out-going lights and feats of ventriloquism that imitated pistol shots and sirens. (2.2)

Romanchik (Darkbloom: "novelette") is a diminutive of roman (love affair; novel).

Skoropostizhnaya konskaya smert' ("A Horse's Sudden Death") was written by Chekhov in 1889 (not "in 1886") and was signed "Akakiy Tarantulov." Chekhov used this penname only twice: another time he signed with it his letter of the beginning of May, 1889, to Suvorin. In this letter Chekhov famously crosses Goncharov (the author of Oblomov) off the list of his demigods. On Desdemonia "artists are the only gods." (3.8) One is reminded of "Schiller Shakespearovich Goethe," as Chekhov signed his letter of November 24, 1887, to his brother Alexander.

*Pushkin used the lines from this fable "Какие крохотны коровки! / Есть, право, менее булавочной головки!" as an epigraph to Sobranie nasekomykh (The Collection of Insects). "Na, sekomoe" ("take this insect, you who was flogged") is little Klim's cruel pun on nasekomoe (insect) in Gorky's novel "The Life of Klim Samgin." Insect is an anagram of incest. Van's sister and life-long lover Ada is "crazy about everythyng that crawls." (1.8)