140 THOPICAL NATUEE, AND OTHER ESSAYS. 



gorget is of sucli a flaming crimson that, as Mr. Gould 

 remarks, it seems to have caught the last spark from 

 the volcano before it was extinguished. 



Not only are humming-birds found over the whole 

 extent of America, from Sitka to Tierra-d'el-Fuego, and 

 from the level of the sea to the snow-line on the Andes, 

 but they inhabit many of the islands at a great distance 

 from the mainland. The West Indian islands possess 

 fifteen distinct species belonging to eight different genera, 

 and these are so unlike any found on the continent that 

 five of these genera are peculiar to the Antilles. Even 

 the Bahamas, so close to Florida, possess two peculiar 

 species. The small group of islands called Tres Marias, 

 about sixty miles from the west coast of Mexico, has a 

 peculiar species. More remarkable are the two humming- 

 birds of Juan Fernandez, situated in the Pacific Ocean, 

 four hundred miles west of Valparaiso in Chili, one of 

 these being peculiar ; while another species inhabits the 

 little island Mas-afuera, ninety miles further west. The 

 Galapagos, though very little further from the mainland 

 and much more extensive, have no humming-birds ; 

 neither have the Falkland islands, and the reason seems 

 to be that both these groups are deficient in forest, and 

 in fact have hardly any trees or large shrubs, while there 

 is a great paucity of flowers and of insect life. 



Humming-birds of Juan Fernandez as illustrating 

 Variation and Natural Selection. — The three species 

 which inhabit Juan Fernandez and Mas-afuera present 

 certain peculiarities of great interest. They form a 

 distinct genus, Eustephanus, one species of which inhabits 

 -Chili as well as the island of Juan Fernandez. This, 

 which may be termed the Chilian species, is greenish in 



