And if we inquire, on the other hand, into the _aboriginal_ species of those islands,--or, at any rate, into such of them whose naturally acquired range embraces the opposite extremes of atmosphere,--we shall detect no less surely (albeit within a narrower space) the result of climatal action on insect form. The _Helops confertus_, Woll., "varies according to the altitude at which it is found; being usually deeply striated and rugose on its lower, but subpicescent and much more lightly sculptured on its upper limits. I have taken specimens indeed on Pico Ruivo, and on the mountain-plain of the Fateiras, which are so far diminished in roughness as almost to resemble, at first sight, the _H. Pluto_[11]." The _Pecteropus Maderensis_, Woll., which ranges from about 2500 feet above the sea to the summits of the loftiest hills, although usually with pale legs, is distinguished by having its femora almost invariably dusky when on its highest elevation; and, following out the analogy with that beetle, the _Trechus alticola_, Woll., should perhaps be regarded as an alpine state of the _T. custos_. The _Calathus complanatus_, Koll., assumes along the upland heights a very different aspect to what it does in the regions below, being generally more piceous and convex, altogether broader (in proportion) and shorter, and with _both_ sexes (though, of course, especially the male) shining. Nor is this principle of topographical variability (the result of climate) less apparent in other countries also. The _Notiophili_, for instance, "are extremely unstable, both in their sculpture and hue, being subject to considerable local modifications, though more particularly affected, it would appear, by altitude. Thus, in our own country, the _N. semipunctatus_, Fab., one of the common representatives of the plains, is found likewise on the summits of the mountains; but at that elevation it becomes liable to great alternations of colour, ranging from pale brassy-brown, with the apex testaceous, into deep black. The sculpture, however, perhaps is nearly as much dependent on other circumstances for its modification as upon altitude, since it seems tolerably clear that proximity to the sea-shore, especially where the localities are saline, will frequently produce a more faintly impressed surface[12]." It has indeed been lately suggested, that the _Helobia nivalis_, Payk., may be perhaps, after all, but a mountain variety of the _H. brevicollis_; the _Leistus montanus_, Steph., of the _L. fulvibarbis_, and the _Patrobus septentrionis_, Dej., of the _P. excavatus_; but of this I think further proof is needed, seeing that certain species do appear to exist which are _strictly_ alpine (that is to say, which have not been, severally, detected in the lower regions of more northern zones); and, in _most_ instances, where aberrations are to be met with from the effect of _altitude_, we have a right to inquire (provided the types from which they are supposed to have originally