stage greater
than the variation in the length of the nectary, then smaller moths
could have reached it and have effected the fertilization. Or if the
growth of the probosces of the moths had from other causes increased
quicker than that of the nectary, or if the increased length of
proboscis had been injurious to them in any way, or if the species of
moth with the longest proboscis had become much diminished by some enemy
or other unfavourable conditions, then, in any of these cases, the
shorter nectaried flowers, which would have attracted and could have
been fertilized by the smaller kinds of moths, would have had the
advantage. And checks of a similar nature to these no doubt have acted
in other parts of the world, and have prevented such an extraordinary
development of nectary as has been produced by favourable conditions in
Madagascar only, and in one single species of Orchid. I may here mention
that some of the large Sphinx moths of the tropics have probosces nearly
as long as the nectary of Angraecum sesquipedale. I have carefully
measured the proboscis of a specimen of Macrosila cluentius from South
America, in the collection of the British Museum, and find it to be nine
inches and a quarter long! One from tropical Africa (Macrosila morganii)
is seven inches and a half. A species having a proboscis two or three
inches longer could reach the nectar in the largest flowers of Angraecum
sesquipedale, whose nectaries vary in length from ten to fourteen
inches. That such a moth exists in Madagascar may be safely predicted;
and naturalists who visit that island should search for it with as much
confidence as Astronomers searched for the planet Neptune,--and I
venture to predict they will be equally successful!

Now, instead of this beautiful self-acting adjustment, the opposing
theory is, that the Creator of the Universe, by a direct act of his
Will, so disposed the natural forces influencing the growth of this one
species of plant as to cause its nectary to increase to this enormous
length; and at the same time, by an equally special act, determined the
flow of nourishment in the organization of the moth, so as to cause its
proboscis to increase in exactly the same proportion, having previously
so constructed the Angraecum that it could only be maintained in
existence by the agency of this moth. But what proof is given or
suggested that this was the mode by which the adjustment took place?
None whatever, except a fee