54 
through which the species and their ancestors have existed, has left 
a very complicated facies, and among the various structures and 
markings of the Lepidoptera (and the same general facts hold good 
for other branches of zoology), are many that have persisted and for 
which now there seems to be no actual use. The fact that every 
species has, in its long ancestral past, carried at each stage of its 
evolution, various peculiar structures and markings, that distinguished 
it from its then allies, and useful to it at the time, and so, back 
through all time during which insects have existed as such, or even 
further back to the first dawn of life, does not seem to be appreciated 
by many naturalists, and that these markings and structures should, 
in some instances, persist in a modified form, when they have ceased 
to be directly useful, although not hurtful, to the species in its present 
form, has raised, in the minds of some naturalists, a suspicion that 
some apparent specific characters are not useful to their possessors, 
and from this, some have gone on to assert that certain of these 
characters never have been useful to the species. If one will carefully 
consider the development of species in time, if one will consider 
our absolute ignorance of these early forms, except such as we can 
gather from analogy by the closest study and comparison of various 
species, it is surely somewhat unsafe, if not illogical, to make such an 
assertion. 
SPONTANEOUS VARIATIONS ACTED UPON BY NATURAL SELECTION IN 
THE MODIFICATION OF SPECIES. 
It is quite true, as Romanes has pointed out, that Darwin himself 
believed that every “ slight individual difference, as well as more 
strongly marked variations which occasionally arise,” had “an efficient 
cause,” and that “ if the cause were to act persistently, it is almost 
certain that all the individuals of the species would be similarly 
modified.” Romanes took his stand on the principle here enunciated, 
and attempted to maintain the position of Darwin with regard to this 
and similar statements. Wallace, however, has shown that this 
reasoning can only be true when the same cause acts persistently 
on identical materials, under identical conditions. He has also further 
pointed out that the very theory of natural selection is based on 
the fact that the materials, i.e ., the individuals or species, are 
not identical, but that they vary indefinitely, and in many direc¬ 
tions even under closely similar conditions, and he asks: “How, 
then, can any external or internal cause produce an identical result — 
a definite new variation—in all the individuals of a species, born as 
they are of varying parents, of different ages, and subject to ever 
fluctuating conditions ? ” The endless variation of almost every 
species of insect, in a more or less marked manner, re-echoes Wal¬ 
lace’s question, and I can see no other conclusion than that natural 
selection has chosen and intensified variations that have occurred 
independently in the species, and modified such into paths that have 
proved useful to the species when any striking change in the environ¬ 
ment has taken place. 
SPECIFIC, GENERIC, TRIBAL, ETC., CHARACTERS UTILITARIAN. 
I quite agree with Wallace that the selection of all variations, 
whether now exhibited as class, family, tribal or generic characters, 
has been brought about by utility to the species, and perfected by 
natural selection. We differentiate our classes, families, tribes and 
