Stein collects butterflies, which may seem like just a passing hobby. But we think there just might be something more to it. Let's take a look at Stein's description of his favorite pasttime:
"When I got up I shook like a leaf with excitement, and when I opened these beautiful wings and made sure what a rare and so extraordinary perfect specimen I had, my head went round and my legs became so weak with emotion that I had to sit on the ground. I had greatly desired to possess myself of a specimen of that species [...]"
He sighed and turned again to the glass case. The frail and beautiful wings quivered faintly, as if his breath had for an instant called back to life that gorgeous object of his dreams. (20.10-5)
Each time Stein captures a butterfly, he must kill it. He both admires and destroys these beautiful bugs, because each time he gets his hands on one, he takes away its freedom, and the beauty of the insect in flight. It's a bit of a contradiction, right? If you love butterflies so much, Stein, perhaps you should leave the poor things alone.
But he can't. For Stein, all beauty is fleeting and all perfect moments must come to an end. His own personal history seems to confirm this: his wife and daughter were tragically killed, and live on only in his dreams and memories. He spends the aftermath of that tragedy tracking down and capturing butterflies, perhaps in an effort to recapture what he has lost.
Aside from personal considerations, Stein's butterfly hunting is also a powerful symbol of the British Empire (and other European empires). Stein goes tromping around foreign places, capturing these things of beauty so he can study them and show off his trophies to his admirers. That sounds eerily familiar when you consider that European imperialism was all about traveling to foreign places and capturing their resources for European use. Perhaps these butterflies represent what is lost when Europeans colonize these far-flung foreign lands.