ere is the result: the cells which at first were sparingly provided,
but whose supplies were doubled or trebled by my artifice, contain
males, as foretold by the original amount of victuals. The surplus which
I added has not completely disappeared, far from it: the larva has had
more than it needed for its evolution as a male; and, being unable to
consume the whole of its copious provisions, it has spun its cocoon in
the midst of the remaining pollen-dust. These males, so richly supplied,
are of handsome but not exaggerated proportions; you can see that the
additional food has profited them to some small extent.

The cells with abundant provisions, reduced to a half or a third by
my intervention, contain cocoons as small as the male cocoons, pale,
translucent and limp, whereas the normal cocoons are dark-brown, opaque
and firm to the touch. These, we perceive at once, are the work of
starved, anaemic weavers, who, failing to satisfy their appetite and
having eaten the last grain of pollen, have, before dying, done their
best with their poor little drop of silk. Those cocoons which correspond
with the smallest allowance of food contain only a dead and shrivelled
larva; others, in whose case the provisions were less markedly
decreased, contain females in the adult form, but of very diminutive
size, comparable with that of the males, or even smaller. As for the
controls which I was careful to leave, they confirm the fact that I had
males in the part near the orifice of the reed and females in the part
near the knot closing the channel.

Is this enough to dispose of the very improbable supposition that the
determination of the sex depends on the quantity of food? Strictly
speaking, there is still one door open to doubt. It may be said that
experiment, with its artifices, does not succeed in realizing the
delicate natural conditions. To make short work of all objections, I
cannot do better than have recourse to facts in which the experimenter's
hand has not intervened. The parasites will supply us with these facts;
they will show us how alien the quantity and even the quality of the
food are from either specific or sexual characters. The subject
of enquiry thus becomes double, instead of single as it was when I
plundered one cell in my split reeds to enrich another. Let us follow
this double current for a little while.

An Ammophila, the Silky Ammophila (Cf. "The Hunting Wasps": chapter
13.--Translator's Note.), which feed