tterflies, and wasps by the legs, and the wonderfully
complex arrangements of the orchids. One of these, our common Orchis
pyramidalis, may be briefly described to show how varied and beautiful
are the arrangements to secure cross-fertilisation. The broad trifid lip
of the flower offers a support to the moth which is attracted by its
sweet odour, and two ridges at the base guide the proboscis with
certainty to the narrow entrance of the nectary. When the proboscis has
reached the end of the spur, its basal portion depresses the little
hinged rostellum that covers the saddle-shaped sticky glands to which
the pollen masses (pollinia) are attached. On the proboscis being
withdrawn, the two pollinia stand erect and parallel, firmly attached to
the proboscis. In this position, however, they would be useless, as they
would miss the stigmatic surface of the next flower visited by the moth.
But as soon as the proboscis is withdrawn, the two pollen masses begin
to diverge till they are exactly as far apart as are the stigmas of the
flower; and then commences a second movement which brings them down
till they project straight forward nearly at right angles to their first
position, so as exactly to hit against the stigmatic surfaces of the
next flower visited on which they leave a portion of their pollen. The
whole of these motions take about half a minute, and in that time the
moth will usually have flown to another plant, and thus effect the most
beneficial kind of cross-fertilisation.[145] This description will be
better understood by referring to the illustration opposite, from
Darwin's _Fertilisation of Orchids_(Fig. 30).

[Illustration: FIG. 30.--Orchis pyramidalis.]

_The Interpretation of these Facts._

Having thus briefly indicated the general character of the more complex
adaptations for cross-fertilisation, the details of which are to be
found in any of the numerous works on the subject,[146] we find
ourselves confronted with the very puzzling question--Why were these
innumerable highly complex adaptations produced, when the very same
result may be effected--and often is effected--by extremely simple
means? Supposing, as we must do, that all flowers were once of simple
and regular forms, like a buttercup or a rose, how did such irregular
and often complicated flowers as the papilionaceous or pea family, the
labiates or sage family, and the infinitely varied and fantastic orchids
ever come into existence? No cause ha