Ch. 10: Mosquitos and Parasite Problems - Page 2

on a hot still day, with a pertinacious
cloud of gnats or sandflies hovering just above my head and keeping me
company for miles, I have always devoutly wished for a stray dragon-fly
to show himself. Frequently the wish has been fulfilled, the dragon-fly,
apparently "sagacious of his quarry from afar," sweeping straight at his
prey, and instantly, as if by miracle, the stinging rain has ceased and
the noxious cloud vanished from overhead, to be re-formed no more. This
has always seemed very extraordinary to me; for in other matters gnats
do not appear to possess even that proverbial small dose of intellect
for which we give most insects credit. Before the advent of the
dragon-fly it has perhaps happened that I have been vigorously striking
at them, making it very unpleasant for them, and also killing and
disabling many hundreds--a larger number than the most voracious
dragon-fly could devour in the course of a whole day; and yet, after
brushing and beating them off until my arms have ached with the
exertion, they have continued to rush blindly on their fate, exhibiting
not the faintest symptom of fear. I suppose that for centuries
mosquitoes have, in this way, been brushed and beaten away with hands
and with tails, without learning caution. It is not in their knowledge
that there are hands and tails. A large animal is simply a field on
which they confidently settle to feed, sounding shrill flourishes on
their little trumpets to show how fearless they are. But the dragon-fly
is very ancient on the earth, and if, during the Devonian epoch, when it
existed, it preyed on some blood-sucking insect from which or Culicidae
have come, then these stupid little insects have certainly had ample
time in which to learn well at least one lesson.

There is not in all organic nature, to my mind, any instance of wasted
energy comparable in magnitude with the mosquito's thirst for blood, and
the instincts and elaborate blood-pumping apparatus with which it is
related. The amount of pollen given off by some wind-fertilized
trees--so great in some places that it covers hundreds of square miles
of earth and water with a film of yellow dust---strikes us as an amazing
waste of material on the part of nature; but in these cases we readily
see that this excessive prodigality is necessary to continue the
species, and that a sufficient number of flowers would not be
impregnated unless the entire trees were bathed for days in the
fertilizing cloud, in which only one out of many millions of floating
particles can ever hit the mark. The mosquito is able to procreate
without ever satisfying its ravenous appetite for blood. To swell its
grey thread-like abdomen to a coral bead is a delight to the insect, but
not necessary to its