ute its ration elsewhere. In vain I prolong
my examination: there is no fluster of any kind. The Volucella grub
is treated as a friend, or at least as a visitor that does not matter.
There is no attempt to dislodge it, to worry it, to put it to flight.
Nor does the grub seem to trouble greatly about those who come and go.
Its tranquillity, tells us that it feels at home.

Here is some further evidence: the grub has plunged, head downwards,
into an empty cell, which is too small to contain the whole of it.
Its hindquarters stick out, very visibly. For long hours, it remains
motionless in this position. At every moment, wasps pass and repass
close by. Three of them, at one time together, at another separately,
come and nibble at the edges of the cell; they break off particles which
they reduce to paste for a new piece of work. The passers by, intent
upon their business, may not perceive the intruder; but these three
certainly do. During their work of demolition, they touch the grub with
their legs, their antennae, their palpi; and yet none of them minds it.
The fat grub, so easily recognized by its queer figure, is left alone;
and this in broad daylight, where everybody can see it. What must it be
when the profound darkness of the burrows protects the visitor with its
mysteries!

I have been experimenting all along with big Volucella grubs, colored
with the dirty red which comes with age. What effect will pure white
produce? I sprinkle on the surface of the combs some larvae that have
lately left the egg. The tiny, snow-white grubs make for the nearest
cells, go down into them, come out again and hunt elsewhere. The
wasps peaceably let them go their way, as heedless of the little white
invaders as of the big red ones. Sometimes, when it enters an occupied
cell, the little creature is seized by the owner, the wasp grub, which
nabs it and turns and returns it between its mandibles. Is this a
defensive bite? No, the wasp grub has merely blundered, taking its
visitor for a proffered mouthful. There is no great harm done. Thanks
to its suppleness, the little grub emerges from the grip intact and
continues its investigations.

It might occur to us to attribute this tolerance to some lack of
penetration in the wasps' vision. What follows will undeceive us: I
place separately, in empty cells, a grub of Saperda scalaria and a
Volucella grub, both of them white and selected so as not to fill the
cell entirely. Their presence is