In the brief sketch I have now given of this interesting subject, such obvious and striking facts alone have been adduced as a traveller's note-book can supply. The argument must therefore lose much of its weight from the absence of detail and accumulated examples. There is, however, such a very general accordance in the phenomena of distribution as separately deduced from the various classes or kingdoms of the organic world, that whenever one class of animals or plants exhibits in a clearly marked manner certain relations between two countries, the other classes will certainly show similar ones, though it may be in a greater or a less degree. Birds and insects will teach us the same truths; and even animals and plants, though existing under such different conditions, and multiplied and dispersed by such a generally distinct process, will never give conflicting testimony, however much they may differ as regards the amount of relationship between distant regions indicated by them, and consequently notwithstanding the greater or less weight either may have in the determining of questions of this nature. This is my apology for offering to the Linnean Society the present imperfect outline in anticipation of the more detailed proofs and illustrations which I hope to bring forward on a future occasion. * * * * * INDEX. Page Acridotheres, 176 Alligator, 3 Amblada, _Walk._, 144 ---- atomaria, _Walk._, 145 Ampsalis, _Walk._, 98 ---- geniata, _Walk._, 99 Ancylus fluviatilis, 39 Anoa, 177 Anodon, 38 Anomia, 37, 58 Anopheles, _Meigen_, 91 ---- vanus, _Walk._, 91 Anoplognathidæ, 183 Ansa depressicornis, 176 Anthomyia, _Meigen_, 141 ---- procellaria, _Walk._, 141 Anthomyides, _Walk._, 140 Anthrax, _Fabr._, 111 ---- antecedens, _Walk._, 111 ---- congrua, _Walk._, 112 ---- degenera, _Walk._, 113 ---- demonstrans, _Walk._, 112 ---- prædicans, _Walk._, 112