der
to suck nectar, but to gnaw off the ridges within the chamber above the
bucket; in doing this they frequently pushed each other into the bucket,
and their wings being thus wetted they could not fly away, but were
compelled to crawl out through the passage formed by the spout or
overflow. Dr. Cruger saw a "continual procession" of bees thus crawling
out of their involuntary bath. The passage is narrow, and is roofed over
by the column, so that a bee, in forcing its way out, first rubs its
back against the viscid stigma and then against the viscid glands of the
pollen-masses. The pollen-masses are thus glued to the back of the
bee which first happens to crawl out through the passage of a lately
expanded flower, and are thus carried away. Dr. Cruger sent me a flower
in spirits of wine, with a bee which he had killed before it had quite
crawled out, with a pollen-mass still fastened to its back. When the
bee, thus provided, flies to another flower, or to the same flower a
second time, and is pushed by its comrades into the bucket and then
crawls out by the passage, the pollen-mass necessarily comes first into
contact with the viscid stigma, and adheres to it, and the flower is
fertilised. Now at last we see the full use of every part of the flower,
of the water-secreting horns of the bucket half-full of water, which
prevents the bees from flying away, and forces them to crawl out through
the spout, and rub against the properly placed viscid pollen-masses and
the viscid stigma.

The construction of the flower in another closely allied orchid, namely,
the Catasetum, is widely different, though serving the same end; and is
equally curious. Bees visit these flowers, like those of the Coryanthes,
in order to gnaw the labellum; in doing this they inevitably touch
a long, tapering, sensitive projection, or, as I have called it, the
antenna. This antenna, when touched, transmits a sensation or vibration
to a certain membrane which is instantly ruptured; this sets free a
spring by which the pollen-mass is shot forth, like an arrow, in the
right direction, and adheres by its viscid extremity to the back of the
bee. The pollen-mass of the male plant (for the sexes are separate in
this orchid) is thus carried to the flower of the female plant, where it
is brought into contact with the stigma, which is viscid enough to
break certain elastic threads, and retain the pollen, thus effecting
fertilisation.

How, it may be asked, in the