y see one's hand before one's
face.

In addition to such darkness as this there were certain difficulties of
access. The house is hidden by great plane-trees; an alley densely
bordered with lilacs and rose-trees make a kind of outer vestibule to
the entrance; it is protected from the _mistral_ by groups of pines and
screens of cypress. A thicket of evergreen shrubs forms a rampart at a
few paces from the door. It was across this maze of leafage, and in
absolute darkness, that the butterflies had to find their way in order
to attain the end of their pilgrimage.

Under such conditions the screech-owl would not dare to forsake its
hollow in the olive-tree. The butterfly, better endowed with its faceted
eyes than the owl with its single pupils, goes forward without
hesitation, and threads the obstacles without contact. So well it
directs its tortuous flight that, in spite of all the obstacles to be
evaded, it arrives in a state of perfect freshness, its great wings
intact, without the slightest flaw. The darkness is light enough for the
butterfly.

Even if we suppose it to be sensitive to rays unknown to the ordinary
retina, this extraordinary sight could not be the sense that warns the
butterfly at a distance and brings it hastening to the bride. Distance
and the objects interposed make the suggestion absurd.

Moreover, apart from illusory refractions, of which there is no question
here, the indications of light are precise; one goes straight to the
object seen. But the butterfly was sometimes mistaken: not in the
general direction, but concerning the precise position of the attractive
object. I have mentioned that the nursery on the other side of the house
to my study, which was the actual goal of the visitors, was full of
butterflies before a light was taken into it. These were certainly
incorrectly informed. In the kitchen there was the same crowd of
seekers gone astray; but there the light of a lamp, an irresistible
attraction to nocturnal insects, might have diverted the pilgrims.

Let us consider only such areas as were in darkness. There the pilgrims
were numerous. I found them almost everywhere in the neighbourhood of
their goal. When the captive was in my study the butterflies did not all
enter by the open window, the direct and easy way, the captive being
only a few yards from the window. Several penetrated the house
downstairs, wandered through the hall, and reached the staircase, which
was barred at the t