While discussing the movie-series "Lost," in the internet, someone puzzled over the presence of polar bears in a tropical scenery, in it and mentioning that he'd also spotted this contrast in Nabokov's "Laughter in the Dark" 

 

This mobservation made me recall other instances when Nabokov describes a blend of reality and unreality that pertain exclusively to his characters's mental intoxication, as if at that moment Nabokov expected a more lucid state from his reader. 

One of his manoeuvres seems to derive from setting side by side pairs of opposite seasons of the year, geographical locations or animals.

 

In "Ada or Ardor,"  the effect of an "artificial moonlight’s blaze," lingers on because "the tropical moonlight she (Marina) had just bathed in...made her especially vulnerable" to Demon's advances. Her lover's consciousness is equally fuzzy "so struck was he by the wonder of that brief abyss of absolute reality between two bogus fulgurations of fabricated life." Some twenty years later, while he inhales the aroma of coffee, Demon is doubly affected "by the shadows of tropical weeds waving in the breeze of his brain."

 

I cannot remember other particular examples of mixing cabbages and kings, dragons and bears to stress a novel's fictional element, an assumption that has been triggered on by a desultory commentary concerning "Lost" and "Laughter in the Dark". I wonder if such "reality-call" may be considered as an "authorial intrusion."

 

btw: Once again, my excuses for having sent on duplicated messages when, to top it all, I skipped the text of a footnote.

Here it is:
** - English Literature in Transition, 1880-1920 Volume 9, Number 2, 1966 E-ISSN: 1559-2715 Print ISSN: 0013-8339 DOI: 10.1353/elt.2010.1378
Havelock Ellis: An Annotated Selected Bibliography of Primary and Secondary Works Glenn S. Project MUSE® - http://muse.jhu.edu/>.