_Deucalion_, also, may be quoted in support of this twofold hypothesis, of the direction, and the slowness, of the former migratory movements. It is an apterous genus, and of eminently sluggish habits; and what is the consequence?--we have a very remarkable species (the _D. oceanicum_, Woll.) on one of the rocks of the Salvages, whilst another (the _D. Desertarum_, Woll.) has been isolated on the two southernmost islands of the Madeiran Group; and of so sedentary a nature is this last, that, although physically unimpeded, it has not, even to this day, overrun the diminutive areas on which, when the surrounding region was submerged, it was originally saved from destruction. So strongly indeed was this fact impressed upon me, when I first detected it, that I shall perhaps be excused for recapitulating _in extenso_ the few reflexions which then suggested themselves to my mind. "There is no genus, perhaps, throughout all the Madeiran Coleoptera, more truly indigenous than _Deucalion_. Confined apparently, so far as these islands are concerned, to the remote and almost inaccessible ridges of the two southern Dezertas, it would seem to bid defiance to the most enthusiastic adventurer who would scale those dangerous heights. Its excessive rarity, moreover, even when the localities are attained, must ever impart to it a peculiar value in the eyes of a naturalist; whilst its anomalous structure and sedentary[60] mode of life give it an additional interest in connexion with that ancient continent, of which these ocean ruins, on which for so many ages it has been cut off, are the undoubted witnesses. Approximating in affinity to _Parmena_ and _Dorcadion_, yet presenting a modification essentially its own, it becomes doubly important in a geographical point of view; and it was therefore with the greater pleasure that I lately received a second representative, from the distant rocks of the Salvages,--midway between Madeira and the Canaries. Differing widely in specific minutiae, yet agreeing to an identity in everything generic, they offer conjointly the strongest presumptive evidence to the _quondam_ existence of many subsidiary links (long since lost, and radiating in all probability from some intermediate type) during the period when the whole of these islands were portions, and perhaps very elevated ones, of a vast continuous land. * * * * * The _Deucalion Desertarum_ is of the utmost rarity, the only two[61] specimens which I have seen having been captured (the first by myself, in 1849; and the second by the Rev. R. T. Lowe, in 1850) on the respective summits of the Middle and Southern Dezertas. So local indeed does it seem to be, that it, apparently, has not extended itself even over the Dezerta Grande (where there are no external obstacles to bar its progress); but retains the very position which in all probability constituted its original centre of dissemination at the remote period of time when this ancient continent received its allotted forms.