ance to insects, after which they have accordingly been named the
Bee Orchis, Fly Orchis, Butterfly Orchis, etc., but it has not yet been
satisfactorily shown what advantage the resemblance is to the plant.

ANTS AND PLANTS

The transference of pollen from plant to plant is by no means the only
service which insects render.

Ants, for instance, are in many cases very useful to plants. They
destroy immense numbers of caterpillars and other insects. Forel
observing a large Ants' nest counted more than 28 insects brought in as
food per minute. In some cases Ants attach themselves to particular
trees, constituting a sort of bodyguard. A species of Acacia, described
by Belt, bears hollow thorns, while each leaflet produces honey in a
crater-formed gland at the base, as well as a small, sweet, pear-shaped
body at the tip. In consequence it is inhabited by myriads of a small
ant, which nests in the hollow thorns, and thus finds meat, drink, and
lodging all provided for it. These ants are continually roaming over the
plant, and constitute a most efficient bodyguard, not only driving off
the leaf-eating ants, but, in Belt's opinion, rendering the leaves less
liable to be eaten by herbivorous mammalia. Delpino mentions that on one
occasion he was gathering a flower of Clerodendrum, when he was himself
suddenly attacked by a whole army of small ants.

INSECTIVOROUS PLANTS

In the cases above mentioned the relation between flowers and insects is
one of mutual advantage. But this is by no means an invariable rule.
Many insects, as we all know, live on plants, but it came upon botanists
as a surprise when our countryman Ellis first discovered that some
plants catch and devour insects. This he observed in a North American
plant, Dionsea, the leaves of which are formed something like a
rat-trap, with a hinge in the middle, and a formidable row of spines
round the edge. On the surface are a few very sensitive hairs, and the
moment any small insect alights on the leaf and touches one of these
hairs the two halves of the leaf close up quickly and catch it. The
surface then throws out a glutinous secretion, by means of which the
leaf sucks up the nourishment contained in the insect.

Our common Sun-dews (Drosera) are also insectivorous, the prey being in
their case captured by glutinous hairs. Again, the Bladderwort
(Utricularia), a plant with pretty yellow flowers, growing in pools and
slow streams, is so called because it bears