her extension of that system. It must be remembered
too that our commerce is not a purely natural growth. It has been ever
fostered by the legislature, and forced to an unnatural luxuriance by
the protection of our fleets and armies. The wisdom and the justice of
this policy have been already doubted. So soon, therefore, as it is seen
that the further extension of our manufactures and commerce would be an
evil, the remedy is not far to seek.

After six weeks' confinement to the house I was at length well, and
could resume my daily walks in the forest. I did not, however, find it
so productive as when I had first arrived at Dobbo. There was a damp
stagnation about the paths, and insects were very scarce. In some of my
best collecting places I now found a mass of rotting wood, mingled with
young shoots, and overgrown with climbers, yet I always managed to
add something daily to my extensive collections. I one day met with
a curious example of failure of instinct, which, by showing it to be
fallible, renders it very doubtful whether it is anything more than
hereditary habit, dependent on delicate modifications of sensation. Some
sailors cut down a good-sized tree, and, as is always my practice, I
visited it daily for some time in search of insects. Among other
beetles came swarms of the little cylindrical woodborers (Platypus,
Tesserocerus, &c.), and commenced making holes in the bark. After a day
or two I was surprised to find hundreds of them sticking in the holes
they had bored, and on examination discovered that the milky sap of the
tree was of the nature of gutta-percha, hardening rapidly on exposure to
the air, and glueing the little animals in self-dug graves. The habit
of boring holes in trees in which to deposit their eggs, was not
accompanied by a sufficient instinctive knowledge of which trees were
suitable, and which destructive to them. If, as is very probable, these
trees have an attractive odour to certain species of borers, it might
very likely lead to their becoming extinct; while other species, to whom
the same odour was disagreeable, and who therefore avoided the dangerous
trees, would survive, and would be credited by us with an instinct,
whereas they would really be guided by a simple sensation.

Those curious little beetles, the Brenthidae, were very abundant in Aru.
The females have a pointed rostrum, with which they bore deep holes in
the bark of dead trees, often burying the rostrum up to the eyes,