Conversation so far:
Why was Vladimir Nabokov interested in entomology?
Vladimir Nabokov's interest in entomology had been inspired by books of Maria Sibylla Merian he had found in the attic of his family's country home in Vyra.
Did Vladimir Nabokov do anything important regarding entomology?
During the 1940s, as a research fellow in zoology, Vladimir Nabokov was responsible for organizing the butterfly collection of the Museum of Comparative Zoology at Harvard University.

Question: What year did he start to get into Entomology?
Self-contained rewrite: What year did Vladimir Nabokov start to get into Entomology?