Korney Chukovsky's (1882-1969) verses are to Russian childhoods what Dr Seuss or Roald Dahl are to English children. Poems such as Doctor Aibolit (Doctor Ouchithurts - character based loosely on Hugh Lofting's Doctor Dolittle) and Krokodil (Crocodile) have been delighting children for generations, while the redoutable washstand of Moidodyr (Wash-em-clean) has been terrifying them into washing behind the ears daily. Moidodyr (which literally means "wash until you get a hole") became a symbol of hygiene and purity and was frequently used in advertising. The character even made it onto a Russian postage stamp.
Chukovsky also wrote a short morality tale called The Stolen Sun, which was made into a celebrated children's film in 1943-4. He was also a literary critic and an accomplished translator.
Two things are worth noting in Nabokov's mention of Chukovsky: he was not, like the Nabokovs, emigrating, on that journey. He was to return to the Soviet Union and live there until his death in 1969. The other is that Chukovsky wrote a popular children's poem, Barmalei, about an ogre of the same name, who lives in "terrible" Africa. The poem is a warning to children not to be naughty and wander off to places like Africa, lest they meet a terrible fate. Barmalei became the prototypical villain in Russian culture, and first made his appearance in a poem of 1916, so Nabokov may have been aware of him, and mentioned the "Afrika" rhyme as a nod towards Barmalei. Nothing, after all, was ever casually tossed into Nabokov's writing!