ur present views as to the relations between the Lamarckian factors and
the Darwinian one of natural selection are shown by the following
summary at the end of this essay.

"1. The more prominent tubercles, and spines or bristles arising
from them, are hypertrophied piliferous warts, the warts, with the
seta or hair which they bear, being common to all caterpillars.

"2. The hypertrophy or enlargement was probably [we should rather
say _possibly_] primarily due to a change of station from herbs to
trees, involving better air, a more equable temperature, perhaps a
different and better food.

"3. The enlarged and specialized tubercles developed more rapidly on
certain segments than on others, especially the more prominent
segments, because the nutritive fluids would tend more freely to
supply parts most exposed to external stimuli.

"4. The stimuli were in great part due to the visits of insects and
birds, resulting in a mimicry of the spines and projections on the
trees; the colors (lines and spots) were due to light or shade,
with the general result of protective mimicry, or adaptation to
tree-life.

"5. As the result of some unknown factor some of the hypodermic
cells at the base of the spines became in certain forms specialized
so as to secrete a poisonous fluid.

"6. After such primitive forms, members of different families, had
become established on trees, a process of arboreal segregation or
isolation would set in, and intercrossing with low-feeders would
cease.

"7. Heredity, or the unknown factors of which heredity is the
result, would go on uninterruptedly, the result being a succession
of generations perfectly adapted to arboreal life.

"8. Finally the conservative agency of natural selection operates
constantly, tending towards the preservation of the new varieties,
species, and genera, and would not cease to act, in a given
direction, so long as the environment remained the same.

"9. Thus in order to account for the origin of a species, genus,
family, order, or even a class, the first steps, causing the
origination of variations, were in the beginning due to the primary
(direct and indirect) factors of evolution (Neolamarckism), and the
final stages were due to the secondary factors, segregation and
natural selection (Darwinism)."

From a late essay[225] we take the following extracts explaining our
views:

"In seeking t