14 MR. A. R. WALLACE ON THE PAPILIONIDÆ 
rather than diminishes. And it must be remembered that the naturalist is rarely likely 
to err on the side of imputing greater indefiniteness to species than really exists. There 
is a completeness and satisfaction to the mind in defining and limiting and naming à 
species, which leads us all to do so whenever we conscientiously can, and which we know 
has led many collectors to reject vague intermediate forms as destroying the symmetry of 
their cabinets. We must therefore consider these cases of excessive variation and insta- 
bility as being thoroughly well established ; and to the objection that, after all, these cases 
are but few compared with those in which species can be limited and defined, and are 
therefore merely exceptions to a general rule, I reply that a true law embraces all 
apparent exceptions, and that to the great laws of nature there are no real exceptions— 
that what appear to be such are equally results of law, and are often (perhaps indeed 
always) those very results which are most important as revealing the true nature and 
action of the law. It is for such reasons that naturalists now look upon the study of 
varieties as more important than that of well-fixed species. It is in the former that we 
see nature still at work, in the very act of producing those wonderful modifications of form, 
that endless variety of colour, and that complicated harmony of relations, which gratify 
every sense and give occupation to every faculty of the true lover of nature. 
Variation as specially influenced by Locality. 
The phenomena of variation as influenced by locality have not hitherto received much 
attention. Botanists, it is true, are acquainted with the influences of climate, altitude, and 
other physical conditions in modifying the forms and external characteristics of plants; 
but I am not aware that any peculiar influence has been traced to locality, independent 
of climate. Almost the only case I can find recorded is mentioned in that repertory of 
natural-history facts, * The Origin of Species,’ viz. that herbaceous groups have a tendency 
to become arborealin islands. In the animal world, I cannot find that any facts have 
been pointed out as showing the special influence of locality in giving a peculiar Sacies 
to the several disconnected species that inhabit it. What I have to adduce on this 
matter will therefore, I hope, possess some interest and novelty. 
On examining the closely allied species, local forms, and varieties distributed over the 
Indian and Malayan regions, I find that larger or smaller districts, or even single islands, 
give a special character to the majority of their Papilionidæ. For instance : 1. The - 
species of the Indian region (Sumatra, Java, and Borneo) are almost invariably smaller 
than the allied species inhabiting Celebes and the Moluccas; 2. The species of New 
Guinea and Australia are also, though in a less degree, smaller than the nearest species 
or varieties of the Moluccas; 3. In the Moluccas themselves the Species of Amboyna are 
the largest; 4. The species of Celebes equal or even surpass in size those of Amboyna ; 
5. The speeies and varieties of Celebes possess a striking ch 
anterior wings, different from that of the allied species and varieties of all the surround- 
ing islands; 6. Tailed species in India i 
spread eastward through the archipelago. 
Having preserved the finest and largest 
and having always taken for comparison t 
that the tables I now give are sufficient 
specimens of Butterflies in my own collection, 
he largest specimens of the same sex, I believe 
ly exact. The differences of expanse of wings 
Lt 
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den Posi AN ERI aad SOUS p Ru 
Pe C NITE Bou OM s 
TE AN 
