45 
vary,” or some similar phrase. One has some difficulty to conceive 
how vastly our facts relating to variation have increased during the 
last half-century. As entomologists, we know very well, that in every 
individual brood of any given species, there is an abundance of 
variations present, upon which natural selection might work in many 
directions. If this be once thoroughly understood, and, if to this be 
added the fact, that an inconceivable percentage of the progeny of 
every living insect (even if only judged by the standard of lack of 
increase in numbers of common species of Lepidoptera in well-known 
localities) is annually destroyed by various causes, nature con¬ 
tinually weeding out the less fit, so that only a few selected and 
well-favoured individuals reach maturity, then one can readily 
conceive that natural selection may have much to do with the 
process of the formation of a new race under the most favourable 
conditions. There can be little doubt that, by a slow process of the 
selection of suitable variations presented by a species, nursed under the 
most favourable conditions, on lines similar to those already indicated, 
species have been formed. 
UTILITY AND THE ORIGIN OF SPECIFIC CHARACTERS. 
It may not be out of place now to say a few words on the evolution 
of those “ specific characters ” which every species possesses, and 
which ultimately result in the differentiation of each individual species 
from all others. I have attempted to show, in certain articles that I 
published on “Mimicry” ( Entom. Record , vol. viii), that utility is the 
mainspring on which the formation of mimetic patterns depends,and that 
utility has guided natural selection to act in ways advantageous to the 
species in their evolution. I would also urge that utility is again 
the guide by which natural selection is driven into the paths 
advantageous to the species, when it brings about the development 
of new forms, which ultimately become new species. On this 
question, Huxley says: “Every variety which is selected into a 
species, is favoured and preserved in consequence of being, in some 
one or more respects, better adapted to its surroundings than its 
rivals. . . . For, as has been pointed out, it is a necessary con¬ 
sequence of the theory of selection, that every species must have some 
one or more structural or functional peculiarities, in virtue of the 
advantage conferred by which it has fought through the crowd of its 
competitors, and achieved a certain duration. In this sense, it is true, 
that every species has been originated by selection.” 'Wallace says: 
“ Perhaps no principle has ever been announced, so fertile in results 
as that which Mr. Darwin so earnestly impresses upon us, and which 
is, indeed, a necessary deduction from the theory of natural selection, 
viz., that none of the definite facts of organic nature, no special organ, 
no characteristic form or marking, no peculiarities of instinct or of 
habit, no relations between species or between groups of species, can 
exist, but which must now be, or once have been, useful to the 
individuals or races which possess them.” Here it is quite evident, 
that two of the greatest thinkers on this subject, accept the principle 
of the utility of specific characters, at any rate, at the time of their 
origin as such; and, although it is possible that certain specific 
characters may exist in certain species which are now of no direct 
advantage to their possessor, yet there can be but little doubt that at 
some previous time in the past history of the species, they were either 
themselves useful, or were correlated with some useful character. 
