I went indoors and upstairs.  This time, in full daylight and without losing a detail, I witnessed once more the astonishing spectacle to which the great nocturnal butterfly had first introduced me.  The study contained a cloud of males, which I estimated, at a glance, as being about sixty in number, so far as the movement and confusion allowed me to count them at all.  After circling a few times over the cage many of them went to the open window, but returned immediately to recommence their evolutions.  The most eager alighted on the cover, trampling on one another, jostling one another, trying to get the best places.  On the other side of the barrier the captive, her great body hanging against the wire, waited immovable.  She betrayed not a sign of emotion in the face of this turbulent swarm.

Going and entering, perched on the cover or fluttering round the room, for more than three hours they continued their frenzied saraband.  But the sun was sinking, and the temperature was slowly falling.  The ardour of the butterflies also cooled.  Many went out not to return.  Others took up their positions to wait for the gaieties of the following day; they clung to the cross-bars of the closed window as the males of the Great Peacock had done.  The rejoicings were over for the day.  They would certainly be renewed on the morrow, since the courtship was without result on account of the barrier of the wire-gauze cover.

But, alas I to my great disappointment, they were not resumed, and the fault was mine.  Late in the day a Praying Mantis was brought to me, which merited attention on account of its exceptionally small size.  Preoccupied with the events of the afternoon, and absent-minded, I hastily placed the predatory insect under the same cover as the moth.  It did not occur to me for a moment that this cohabitation could lead to any harm.  The Mantis was so slender, and the other so corpulent!

Alas!  I little knew the fury of carnage animating the creature that wielded those tiny grappling-irons!  Next morning I met with a disagreeable surprise:  I found the little Mantis devouring the great moth.  The head and the fore part of the thorax had already disappeared.  Horrible creature! at what an evil hour you came to me!  Goodbye to my researches, the plans which I had caressed all night in my imagination!  For three years for lack of a subject, I was unable to resume them.

Bad luck, however, was not to make me forget the little I had learned.  On one single occasion about sixty males had arrived.  Considering the rarity of the Oak Eggar, and remembering the years of fruitless search on the part of my helpers and myself, this number was no less than stupefying.  The undiscoverable had suddenly become multitudinous at the call of the female.

Whence did they come?  From all sides, and undoubtedly from considerable distances.  During my prolonged searches every bush and thicket and heap of stones in my neighbourhood had become familiar to me, and I can assert that the Oak Eggar was not to be found there.  For such a swarm to collect as I found in my laboratory the moths must have come from all directions, from the whole district, and within a radius that I dare not guess at.