elect those flowers which display them by
preference over any less developed types; for bees and butterflies are
the most highly adapted of all insects to honey-seeking and
flower-feeding. They have themselves on their side undergone the largest
amount of specialization for that particular function. And if the more
specialized and modified flowers, which gradually fitted their forms and
the position of their honey-glands to the forms of the bees or
butterflies, showed a natural tendency to pass from yellow through pink
and red to purple and blue, it would follow that the insects which were
being evolved side by side with them, and which were aiding at the same
time in their evolution, would grow to recognize these developed colors
as the visible symbols of those flowers from which they could obtain the
largest amount of honey with the least possible trouble. Thus it would
finally result that the ordinary unspecialized flowers, which depended
upon small insect riff-raff, would be mostly left yellow or white; those
which appealed to rather higher insects would become pink or red; and
those which laid themselves out for bees or butterflies, the aristocrats
of the arthropodous world, would grow for the most part to be purple
or blue.

Now, this is very much what we actually find to be the case in nature.
The simplest and earliest flowers are those with regular, symmetrical
open cups, like the _Ranunculus_ genus, the _Potentillas_, and the
_Alsine_ or chickweeds, which can be visited by any insects whatsoever;
and these are in large part yellow or white. A little higher are flowers
like the Campions or _Sileneoe_, and the stocks (_Matthiola_), with more
or less closed cups, whose honey can only be reached by more specialized
insects; and these are oftener pink or reddish. More profoundly modified
are those irregular one-sided flowers, like the violets, peas, and
orchids, which have assumed special shapes to accommodate bees and other
specific honey-seekers; and these are often purple and not unfrequently
blue. Highly specialized in another way are the flowers like harebells
(_Campanulaceoe_), scabious (_Dipsaceoe_), and heaths (_Ericaceoe_),
whose petals have all coalesced into a tubular corolla; and these might
almost be said to be usually purple or blue. And finally, highest of all
are the flowers like labiates (rosemary, _Salvia_, etc.) and speedwells
(_Veronica_), whose tubular corolla has been turned to one side, thus
c