rough, or widening into stations when it strikes a vein with a
better flavour; now, it makes a short, straight, roomy corridor,
leading with a sharp bend to the outside world. It had plenty of time
during its capricious wanderings; the adult has none to spare: his
days are numbered; he must get out as quickly as he can. Hence the
shortest road and as little encumbered by obstacles as is consistent
with safety. The grub knows that the too sudden junction of the
horizontal and the vertical part would stop the stiff, inflexible
insect and bends it towards the outside with a gentle curve. This
elbow changing the direction occurs whenever the larva ascends from
the depths; it is very short when the nymphosis-chamber is next to the
surface, but continues for some length when the chamber is well inside
the trunk. In this case, the path traced by the grub has so regular a
curve that you feel inclined to subject the work to geometrical
measurement.

For want of sufficient data, I should have left this elbow in the
shadow of a note of interrogation, had I had at my disposal only the
emergence-galleries of the Longicorns and Buprestes, which are too
short to lend themselves to trustworthy examination with the
compasses. A lucky find provided me with the factors required. This
was the trunk of a dead poplar, riddled, to a height of several yards,
with an infinite number of round holes the diameter of a pencil. The
precious pole, still standing, is uprooted with due respect, in view
of my designs, and carried into my study, where it is sawn into
longitudinal sections planed smooth.

The wood, while retaining its structure, has been greatly softened by
the presence of the mycelium of a mushroom, the agaric of the poplar.
The inside is decayed. The outer layers, to a depth of over four
inches, are in good condition, save for the innumerable curved
passages that cut through them. In a section involving the whole
diameter of the trunk, the galleries of the late occupant produce a
pleasing effect, of which a sheaf of corn gives us a pretty faithful
image. Almost straight, parallel with one another and assembled in a
bundle down the middle, they diverge at the top and spread into a
cluster of wide curves, each of which ends in one of the holes on the
surface. It is a sheaf of passages which has not the single head of a
sheaf of corn, but shoots its innumerable sprouts hither and thither,
at all heights.

I am enraptured by this magnif