shorter spur holds out a certain prospect of reward; for, in these two
cases, as in so many others, the flower's welcome for an insect is in
exact proportion to the length of its visitor's tongue. Doubtless it is
one of the smaller sphinx moths, such as we see at dusk working about
the evening primrose and other flowers deep of chalice, and heavily
perfumed to guide visitors to their feast, that is the great
Purple-fringed Orchid's benefactor, since the length of its tongue is
perfectly adapted to its needs. Attracted by the showy, broad lower
petal, his wings ever in rapid motion, the moth proceeds to unroll his
proboscis and drain the cup that is frequently an inch and a half deep.
Thrusting in his head, either one or both of his large, projecting eyes
are pressed against the sticky button-shaped discs to which the pollen
masses are attached by a stalk, and as he raises his head to depart,
feeling that he is caught, he gives a little jerk that detaches them,
and away he flies with these still fastened to his eyes.

Even while he is flying to another flower, that is to say, in half a
minute, the stalks of the pollen masses bend downward from the
perpendicular and slightly toward the centre, or just far enough to
require the moth, in thrusting his proboscis into the nectary, to strike
the glutinous, sticky stigma. Now, withdrawing his head, either or both
of the golden clubs he brought in with him will be left on the precise
spot where they will fertilize the flower. Sometimes, but rarely, we
catch a butterfly or moth from the smaller or larger purple orchids with
a pollen mass attached to his tongue, instead of to his eyes; this is
when he does not make his entrance from the exact centre--as in these
flowers he is not obliged to do--and in order to reach the nectary his
tongue necessarily brushes against one of the sticky anther sacs. The
performance may be successfully imitated by thrusting some blunt point
about the size of a moth's head, a dull pencil or a knitting-needle,