of installing
its family.

It opens before the Osmia's egg. The tiny grub, as soon as it is born,
begins to drain the rival egg, of which it occupied the top part, high
up above the honey. The extermination soon becomes perceptible. You can
see the Osmia's egg turning muddy, losing its brilliancy, becoming limp
and wrinkled. In twenty-four hours, it is nothing but an empty sheath,
a crumpled bit of skin. All competition is now removed; the parasite is
the master of the house. The young grub, when demolishing the egg, was
active enough: it explored the dangerous thing which had to be got
rid of quickly, it raised its head to select and multiply the
attacking-points. Now, lying at full length on the surface of the honey,
it no longer shifts its position; but the undulations of the digestive
canal betray its greedy absorption of the Osmia's store of food. The
provisions are finished in a fortnight and the cocoon is woven. It is
a fairly firm ovoid, of a very dark-brown colour, two characteristics
which at once distinguish it from the Osmia's pale, cylindrical cocoon.
The hatching takes place in April or May. The puzzle is solved at
last: the Osmia's parasite is a Wasp called the Spotted Sapyga (Sapyga
punctata, V.L.)

Now where are we to class this Wasp, a true parasite in the strict
sense of the word, that is to say, a consumer of others' provisions. Her
general appearance and her structure make it clear to any eye more or
less familiar with entomological shapes that she belongs to a species
akin to that of the Scoliae. Moreover, the masters of classification, so
scrupulous in their comparison of characteristics, agree in placing the
Sapygae immediately after the Scoliae and a little before the Mutillae.
The Scoliae feed their grubs on prey; so do the Mutillae. The Osmia's
parasite, therefore, if it really derives from a transformed ancestor,
is descended from a flesh-eater, though it is now an eater of honey. The
Wolf does more than become a Sheep: he turns himself into a sweet-tooth.

'You will never get an apple-tree out of an acorn,' Franklin tells us,
with that homely common-sense of his.

In this case, the passion for jam must have sprung from a love of
venison. Any theory might well be deficient in balance when it leads to
such vagaries as this.

I should have to write a volume if I would go on setting forth my
doubts. I have said enough for the moment. Man, the insatiable enquirer,
hands down from age to ag