thus prevented. The Bee now begins the whole
performance over again, that is to say, she once more dives head first
to the bottom of the cell, though she has nothing left to disgorge, as
her crop has just been emptied. When this is done, it is the belly's
turn. I instantly push her aside again. The insect repeats its
proceedings, still entering head first; I also repeat my touch of the
straw. And this can go on as long as the observer pleases. Pushed aside
at the moment when she is about to insert her abdomen into the cell, the
Bee goes back to the opening and persists in going down head first
to begin with. Sometimes, she descends to the bottom, sometimes only
half-way, sometimes again she only pretends to descend, just bending her
head into the aperture; but, whether completed or not, this action, for
which there is no longer any motive, since the honey has already been
disgorged, invariably precedes the entrance backwards to deposit the
pollen. It is almost the movement of a machine whose works are only set
going when the driving-wheel begins to revolve.

CHAPTER 4. MORE ENQUIRIES INTO MASON-BEES.

This chapter was to have taken the form of a letter addressed to Charles
Darwin, the illustrious naturalist who now lies buried beside Newton in
Westminster Abbey. It was my task to report to him the result of
some experiments which he had suggested to me in the course of our
correspondence: a very pleasant task, for, though facts, as I see them,
disincline me to accept his theories, I have none the less the deepest
veneration for his noble character and his scientific honesty. I was
drafting my letter when the sad news reached me: Darwin was dead; after
searching the mighty question of origins, he was now grappling with
the last and darkest problem of the hereafter. (Darwin died at Down,
in Kent, on the 19th of April 1882.--Translator's Note.) I therefore
abandon the epistolary form, which would be unwarranted in view of that
grave at Westminster. A free and impersonal statement shall set forth
what I intended to relate in a more academic manner.

One thing, above all, had struck the English scientist on reading the
first volume of my "Souvenirs entomologiques", namely, the Mason-bees'
faculty of knowing the way back to their nests after being carried to
great distances from home. What sort of compass do they employ on their
return journeys? What sense guides them? The profound observer thereupon
spoke of an experim