All alone in a great case by itself was pinned the purple emperor, the Apatura Iris, that fatal specimen that had given the Purple Emperor his name and quietus.

I remembered the butterfly, and stood looking at it with bent eyebrows.

Le Bihan glanced up from the floor where he was nailing down the lid of a box full of cases.

"It is settled, then," said he, "that madame, your wife, gives the Purple Emperor's entire Collection to the city of Paris?"

I nodded.

"Without accepting anything for it?"

"It is a gift," I said.

"Including the purple emperor there in the case? That butterfly is worth a great deal of money," persisted Le Bihan.

"You don't suppose that we would wish to sell that specimen, do you?" I answered a trifle sharply.

"If I were you I should destroy it," said the mayor in his high-pitched voice.