its legs for running. Not being aware of this fact, the insect, more
than once, as I cautiously approached with my forceps, shuffled on one
side just as the instrument was on the point of closing, and thus
escaped. But a far more singular fact is the power which this species
possesses of making a noise. [6] Several times when a pair, probably
male and female, were chasing each other in an irregular course, they
passed within a few yards of me; and I distinctly heard a clicking
noise, similar to that produced by a toothed wheel passing under a
spring catch. The noise was continued at short intervals, and could be
distinguished at about twenty yards' distance: I am certain there is no
error in the observation.
I was disappointed in the general aspect of the Coleoptera. The number
of minute and obscurely coloured beetles is exceedingly great. [7] The
cabinets of Europe can, as yet, boast only of the larger species from
tropical climates. It is sufficient to disturb the composure of an
entomologist's mind, to look forward to the future dimensions of a
complete catalogue. The carnivorous beetles, or Carabidae, appear in
extremely few numbers within the tropics: this is the more remarkable
when compared to the case of the carnivorous quadrupeds, which are so
abundant in hot countries. I was struck with this observation both on
entering Brazil, and when I saw the many elegant and active forms of
the Harpalidae re-appearing on the temperate plains of La Plata. Do
the very numerous spiders and rapacious Hymenoptera supply the place of
the carnivorous beetles? The carrion-feeders and Brachelytra are very
uncommon; on the other hand, the Rhyncophora and Chrysomelidae, all of
which depend on the vegetable world for subsistence, are present in
astonishing numbers. I do not here refer to the number of different
species, but to that of the individual insects; for on this it is that
the most striking character in the entomology of different countries
depends. The orders Orthoptera and Hemiptera are particularly
numerous; as likewise is the stinging division of the Hymenoptera the
bees, perhaps, being excepted. A person, on first entering a tropical
forest, is astonished at the labours of the ants: well-beaten paths
branch off in every direction, on which an army of never-failing
foragers may be seen, some going forth, and others returning, burdened
with pieces of green leaf, often larger than their own bodies.
A small dark-coloured ant sometimes migrates in countless numbers. One
day, at Bahia, my attention was drawn by observing many spiders,
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