to do, she sets up partitions; she divides a tunnel
into cells that will remain empty; she closes with a thick plug reeds
containing nothing. Thus is the modicum of strength of her decline
exhausted in vain labours. The other Builder-bees behave likewise. I see
Anthidia laboriously provide numerous bales of cotton to stop galleries
wherein never an egg was laid; I see Mason-bees build and then
religiously close cells that will remain unvictualled and uncolonized.

The long and useless barricades then belong to the last hours of the
Megachile's life, when the eggs are all laid; the mother, whose ovaries
are exhausted, persists in building. Her instinct is to cut out and heap
up pieces of leaves; obeying this impulse, she cuts out and heaps up
even when the supreme reason for this labour ceases. The eggs are no
longer there, but some strength remains; and that strength is expended
as the safety of the species demanded in the beginning. The wheels of
action go on turning in the absence of the motives for action; they
continue their movement as though by a sort of acquired velocity. What
clearer proof can we hope to find of the unconsciousness of the animal
stimulated by instinct?

Let us return to the Leaf-cutter's work under normal conditions.
Immediately after a protective barrier comes the row of cells, which
vary considerably in number, like those of the Osmia in her reed.
Strings of about a dozen are rare; the most frequent consist of five or
six. No less subject to variation is the number of pieces joined to make
a cell: pieces of two kinds, some, the oval ones, forming the honey-pot;
others, the round ones, serving as a lid. I count, on an average, eight
to ten pieces of the first kind. Though all cut on the pattern of an
ellipse, they are not equal in dimensions and come under two categories.
The larger, outside ones are each of them almost a third of the
circumference and overlap one another slightly. Their lower end bends
into a concave curve to form the bottom of the bag. Those inside, which
are considerably smaller, increase the thickness of the sides and fill
up the gaps left by the first.

The Leaf-cutter therefore is able to use her scissors according to the
task before her: first, the large pieces, which help the work forward,
but leave empty spaces; next, the small pieces, which fit into the
defective portions. The bottom of the cell particularly comes in for
after-touches. As the natural curve of the l