sprung obtain in the less-elevated portions of the same country), _where are the intermediate links_? Now I am not aware that any such links have, in the examples above cited, ever been observed; whilst I can vouch that in at any rate many districts where the _quasi_ variety is found, the descendants of its assumed progenitor _do_ occur in the plains beneath. I have remarked that the _Cicindelidae_ often become inconstant in colouring as they approach their maximum of height above the sea; and I have but little doubt that the _C. fasciatopunctata_[13], Germ., from Asia Minor and Turkey, is the _C. sylvatica_ modified by a long residence in elevated regions. And so it is with the _Chrysomelae_, many of which become, in the loftiest altitudes to which they ascend (as I have noticed at the head of the St. Gotthard Pass of the Swiss Alps), subject to unusual changes, both in lustre and hue. The above examples, although few and indiscriminately selected, will serve to illustrate the principle which we have been contending for,--that climatal influences generally, may (and in most instances do) tend to affect, more or less directly, the outward contour of the insect tribes. It will be remarked that, in the cases hitherto cited no great disturbing power has been made evident,--the aberrations to which we have appealed being, most of them, comparatively minute. This, however, is simply in harmony with the belief which we have already expressed, that climatal causes, when taken singly and alone, are not of primary importance whilst discussing the question of specific modification. It remains for us, in the following sections, to inquire, whether there are any other elements at work from which greater results are to be expected. Meanwhile, let us not forget that differences _may_ be, in the strictest sense, significant, even whilst small; and that it is their _constancy_, rather than their magnitude, which more particularly concerns us in the present treatise, seeing that it is with reference to those distinctions which are less conspicuous that the greatest amount of misunderstanding (through the fact of their being _fixed_) usually prevails; whilst it is our main object to show that dissimilarities do not _necessarily_ imply the specific isolation of the creatures which display them, merely because they are, in their several localities, _permanent_. Sec. II. _Temporary heat or cold, of an unusual degree._