And so it is with the Insecta; many of the larger groups of which (as _Amycterus_ and _Paropsis_, in Australia; _Pachyrhynchus_ and _Apocyrtus_, in the Philippine Islands; _Hipporhinus_, _Monochelus_, _Dichelus_, and _Moluris_, in Southern Africa; _Macronota_, in Java; and _Naupactus_, _Hypsonotus_, _Centrinus_, _Platyomus_, and _Cyrtonota_, in South America) are confined to countries of proportionate magnitude, whilst the smaller ones are more commonly (as it were) shaped out for special provinces or regions, according as local circumstances may require primary adaptations to harmonize with them. Thus, whilst we frequently find an extensive genus diffused over the greater portion of the known world, we perceive that even its _structural_ characteristics are not uniform throughout, but afford fixed geographical modifications (_not_, in this case, however, the effect of development),--which have often, in their turn, obtained the name of 'genera,' and have been described as such. Whether genera, however, or not, they are undeniably small topographical assemblages, satellites around their central types; and they may therefore be safely regarded as genera, if we choose to view them in that light. Of such a nature I have already pointed out[68] is _Saprinus_, as compared with _Hister_; _Atlantis_ with _Laparocerus_; and _Oxyomus_ with _Aphodius_; and, I might also add, _Mesites_ with _Cossonus_. I believe indeed that _Mesites_ will be found to attain its maximum on the Pyrenees (I already possess two or three species, in abundance, from that region); and, if such should be the case, we shall be able to appreciate the significance of two representatives so closely allied as the _M. Tardii_ and _Maderensis_,--one of which has been given off in the direction of Ireland, and the other of the Madeiran Archipelago. But I will not digress further on the subject of this Atlantic province; since, however much I may individually regard it as a reality of the past (which the Coleopterous statistics have compelled me to do), it must of necessity remain, as heretofore, a matter of much controversy and doubt. I should indeed apologize for having trespassed on the reader's attention, in wandering this far from the immediate results of _subsidences_,--which I proposed, at the outset of this chapter, to examine, with reference to the impeded diffusion of the Annulose races. Nevertheless, concluding that a practical illustration of the effects of one of those great downward movements to which geology so repeatedly bears witness would not be irrelevant to the _assumed consequences_ which I had previously ventured to define, I have acted on that judgment; and, having finished my task, will now proceed to notice, briefly, a few other considerations which should not be omitted, when inquiring into insect distribution as influenced by geological phaenomena.