My sincere thanks to Abdellah Bouazza and Brian Boyd for trying to help me trace the source or sources of "that vortex of yellow and maroon butterflies that so pleased Chateaubriand on his arrival in America" (says unreliable Kinbote).
Though Chateaubriand, drawing from experience or from what he read, does mention butterflies and moths in his Memoirs and in other writings, no convincing source seems to be identified.
Is Kinbote to blame (what would be the novelist's purpose then?) or is Nabokov confusing authors? I cannot say and leave the matter to other perplexed researchers and readers!
Didier Machu