muscorum, sucking the former in a proper manner, though they sometimes bite
holes through the corolla. (1/5. H. Muller has also seen Anthophora pilipes and
a Bombylius sucking the flowers. 'Nature' December 10, 1874 page 111.) No doubt
moths likewise visit the flowers, as one of my sons caught Cucullia verbasci in
the act. The pollen readily adheres to any thin object which is inserted into a
flower. The anthers in the one form stand nearly, but not exactly, on a level
with the stigma of the other; for the distance between the anthers and stigma in
the short-styled form is greater than that in the long-styled, in the ratio of
100 to 90. This difference is the result of the anthers in the long-styled form
standing rather higher in the tube than does the stigma in the short-styled, and
this favours their pollen being deposited on it. It follows from the position of
the organs that if the proboscis of a dead humble-bee, or a thick bristle or
rough needle, be pushed down the corolla, first of one form and then of the
other, as an insect would do in visiting the two forms growing mingled together,
pollen from the long-stamened form adheres round the base of the object, and is
left with certainty on the stigma of the long-styled form; whilst pollen from
the short stamens of the long-styled form adheres a little way above the
extremity of the object, and some is generally left on the stigma of the other
form. In accordance with this observation I found that the two kinds of pollen,
which could easily be recognised under the microscope, adhered in this manner to
the proboscides of the two species of humble-bees and of the moth, which were
caught visiting the flowers; but some small grains were mingled with the larger
grains round the base of the proboscis, and conversely some large grains with
the small grains near the extremity of the proboscis. Thus pollen will be
regularly carried from the one form to the other, and they will reciprocally
fertilise one another. Nevertheless an insect in withdrawing its proboscis from
the corolla of the long-styled form cannot fail occasionally to leave pollen
from the same flower on the stigma; and in this case there might be self-
fertilisation. But this will be much more likely to occur with the short-styled
form; for when I inserted a bristle or other such object into the corolla of