smia, she frequents in particular the
monstrous nests of the Chalicodoma of the Sheds. I therefore thought
out a scheme for making the Three-horned Osmia accept my study as her
settlement and build her nests in glass tubes, through which I could
easily watch the progress. To these crystal galleries, which might well
inspire a certain distrust, were to be added more natural retreats:
reeds of every length and thickness and disused Chalicodoma-cells taken
from among the biggest and the smallest. A scheme like this sounds mad.
I admit it, while mentioning that perhaps none ever succeeded so well
with me. We shall see as much presently.

My method is extremely simple. All I ask is that the birth of my
insects, that is to say, their first seeing the light, their emerging
from the cocoon, should take place on the spot where I propose to make
them settle. Here there must be retreats of no matter what nature,
but of a shape similar to that in which the Osmia delights. The first
impressions of sight, which are the most long-lived of any, shall bring
back my insects to the place of their birth. And not only will the
Osmiae return, through the always open windows, but they will always
nidify on the natal spot if they find something like the necessary
conditions.

And so, all through the winter, I collect Osmia-cocoons, picked up in
the nests of the Mason-bee of the Sheds; I go to Carpentras to glean a
more plentiful supply in the nests of the Hairy-footed Anthophora, that
old acquaintance whose wonderful cities I used to undermine when I
was studying the history of the Oil-beetles. (This study is not yet
translated into English; but cf. "The Life of the Fly": chapters 2
and 4.--Translator's Note.) Later, at my request, a pupil and intimate
friend of mine, M. Henri Devillario, president of the civil court at
Carpentras, sends me a case of fragments broken off the banks frequented
by the Hairy-footed Anthophora and the Anthophora of the Walls, useful
clods which furnish a handsome adjunct to my collection. Indeed, at the
end, I find myself with handfuls of cocoons of the Three-horned Osmia.
To count them would weary my patience without serving any particular
purpose.

I spread out my stock in a large open box on a table which receives
a bright diffused light but not the direct rays of the sun. The table
stands between two windows facing south and overlooking the garden. When
the moment of hatching comes, those two windows will al