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Show 272 ISLAND LIFE. (PART II. distant Bermudas almost every year, and extend m. g 1' ts ranoer e . as far as Paraguay, is the only species of land-bird which ~emams completely unchanged in the Galapagos; and we may therefore conclude that some stragglers of the ·migrating host reach the islands sufficiently often to keep up the purity of the bree~. Next, we have the almost cosmopolite short-eared owl (.Asw biachyot~ts), which ranges from China to Ireland, and from Gre~nland to the Straits of Magellan, and of this the Galapagos ~rrd is probably only one of the numerous variet~es. The ht~le wood warbler (Dendr03ca auTeola) is closely alhed to a species which rancres over the whole of North America and as far south as New C;renada. It has also been occasionally met with in Bermuda an indication that it has considerable powers of flight and end~rance. The more distinct species-as the mockingthrushes (Mimus), the tyrant fly-catchers (Pyroce~halus and Myiarchus), and the ground dove (Zenaida), are all alhed to nonmigratory species peculiar to tropical America, an~ of a more restricted range; while the distinct geneTa are alhed to South American groups of finches and sugar-birds which have usually restricted ranges, and whose habits are such as not to render them likely to be carried out to sea. The remote ancestral forms of these birds which, owing to some exceptional causes, reached the Galapagos, have thus remained uninfluenced by later migrations, and have, in consequence, been developed into a variety of distinct types adapted to the peculiar conditions of existence under which they have been placed. Sometimes the different species thus formed are confined to one or two of the islands only, as the two species of Certhidea, which are divided between the islands but do not appear ever to occur together. Mim~ts paTv~tlus is confined to Albemarle Island, and M. tTijasciatus to Charles Island; GactoTnis pallida to Indefatigable Island, and 0. abingdoni to Abingdon Island. Now all these phenomena are strictly consistent with the theory of the peopling of the islands by accidental migrations, if we only allow them to have existed for a sufficiently long period ; and the fact that volcanic action has ceased on many of the islands, as well as their great extent, would certainly indicate a considerable antiquity. C'IJAJ'. Xlll,] TIIg GALAPAGOS ISL\NDS. 273 The great difference presented. by the bin).s of these islandR as compared with those of the equally remote Azores and Bermudas, is sufficiently explained by the difference of climatal conditions. At the Galapagos there are none of those periodic storms, gales, and hurricanes which prevail in the North Atlantic, and which every year carry some straggling birds of Europe or North America to the former islands · while at the same tu. ne, the majority of the tropical American bi'r ds are' non-micrra-tory, and thus afford none of the opportunities presented by 0 thc countless hosts of migrants which pass annually northward and southward along the European, and especially along the North American coasts. It is strictly in accordance with these different c~mlitions that we find in one case an almost perfect identity With, and in the other an al:nost equally complete diversity from, the continental species of birds. Insects and Land-shells.-The otl1er groups of land-animals add little of importance to the facts already referred to. The insects arc very scanty; the most plentiful group, the beetles, o~1ly furnishing about thirty-five species belonging to twentynnw genera and eighteen f<-1milics. The species arc almost a.U peculiar, as are some of the genera. They arc mostly small and obscure insects, allied either to American or to world-wide groups. The Carabidrn and the Heteromera me the most abundant groups, the former furnishing six aml the latter eight species. I 1 The following li:;t of the beetles yet known from tlic Gnlnpngos Rhows their s~anty pr~portions and accidental character; the thirty-seven species belongmg to thnty-one genera and eighteen families. It is taken from Mr. Waterhouse's enumeration in tho P1·oceedings of the Z oological Society for 1877 (p. 81) :- CARABlDlE. F eronia calathoides. , insularis. ,, galapagoensis. Amblygnathus obscuricornis. Solonophorus galapagoonsis. Notaphus galapagoensi~.:~. DYTISClDiE. Euncctes occidentalis. MALACO DER~! S . Ablechrus darwiuii. Corynetes rutipes. Bostrichus unciniatus. LAMELLTCORNEf: . Copris lugubris. Oryctes galapagoensis. ELA'l'ERIDJJ~. Physorhinus gn.lapagoonsis. T |