unwittingly do the flower's bidding while they feast now here,
now there. In spite of Sprengel's most patient and scientific
research, that shed great light on the theory of natural
selection a half century before Darwin advanced it, he never knew
that flowers are nearly always sterile to pollen of another
species when carried to them on the bodies of insect visitors, or
that cross-pollenized blossoms defeat the self-pollinated ones in
the struggle for survival. These facts Darwin proved in endless
experiments.

Because bees depend absolutely upon flowers, not only for their
own food but for that of future generations for whom they labor;
because they are the most diligent of all visitors, and are
rarely diverted from one species of flower to another while on
their rounds collecting, as they must, both nectar and pollen, it
follows they are the most important fertilizing agents. It is
estimated that, should they perish, more than half the flowers in
the world would be exterminated with them! Australian farmers
imported clover from Europe, and although they had luxuriant
fields of it, no seed was set for next year's planting, because
they had failed to import the bumblebee. After his arrival, their
loss was speedily made good.

Ages before men cultivated gardens, they had tiny helpers they
knew not of. Gardeners win all the glory of producing a Lawson
pink or a new chrysanthemum; but only for a few seasons do they
select, hybridize, according to their own rules of taste. They
take up the work where insects left it off after countless
centuries of toil. Thus it is to the night-flying moth, long of
tongue, keen of scent, that we are indebted for the deep, white,