I placed the female in a large glass jar, and laced a piece of thin cotton batting over the mouth for a cover; this again guarded the secret of my laboratory.

Not a male appeared.
But when I placed the females in boxes which were imperfectly closed, or which had chinks in their sides, or even hid them in a drawer or a cupboard, I found the males arrived in numbers as great as when the object of their search lay in the cage of open wire-work freely exposed on a table.

I have a vivid memory of one evening when the recluse was hidden in a hat-box at the bottom of a wall-cupboard.

The arrivals went straight to the closed doors, and beat them with their wings, _toc-toc_, trying to enter.

Wandering pilgrims, come from I know not where, across fields and meadows, they knew perfectly what was behind the doors of the cupboard.
So we must abandon the idea that the butterfly has any means of communication comparable to our wireless telegraphy, as any kind of screen, whether a good or a bad conductor, completely stops the signals of the female.