266 REPORT OF NATIONAL MUSEUM, 1890. 



to include the entire isthmus as far as the coast region of Mexico, thus 

 restricting the Mexican Province to the plateau region and higher 

 lands for an undetermined distance southward, probably not farther 

 than the highlands of Guatemala, Honduras, and northern Nicaragua, 

 but possibly including the higher summits of Costa Rica, where a con- 

 siderable number of northern types occur.* 



Of all these " provinces " the composite one, which I have termed 

 the Colombo- Amazonian, is incomparably the richest in bird life of any 

 region of the earth ; and it is therefore not strange that nearly one- 

 half of all the known species of Humming Birds should be peculiar to 

 its territory. The next in comparative richness in birds of this family 

 is probably the Mexican, in its comprehensive sense, for owing to the 

 carelessness of authors in designating localities it is at present imprac- 

 ticable to separate the species which properly belong to this province 

 from those belonging to the northern extension of the preceding one. 

 Of the 93 species and 23 genera peculiar to the country north of the 

 Isthmus of Panama, about 55 species and 14 genera do not occur south 

 of Gautemala or Honduras. The Brazilian Province probably comes 

 next in number of peculiar species, but it is at present impossible to tell 

 just how many should be credited to it, a very considerable proportion of 

 the 38 species whose range is given as " Brazil " undoubtedly belonging 

 to Colombo- Amazonian Province. From the comparatively small num- 

 ber of Humming Birds peculiar to the Brazilian Province there is a 

 decided falling off in those of the West Indian Province, where we are 

 able to count only 18 peculiar species ; but this number seems large 

 compared with the showing made by the two most widely separated 

 and coldest provinces, the North American and the Chilian, which have 

 only 8 and 5 species, respectively, of Humming Birds peculiar to them. 



The grand centre or focus of the family of Humming Birds is that 

 portion of the Colombo- Amazonian Province comprised within the limits 

 of the State of Ecuador, where considerably more than 100 species occur 

 (more than one-fifth of all that are known), more than half of them 

 occurring nowhere else. Colombia is nearly as rich, having about 100 

 species, nearly 50 of which are peculiar. Peru and Bolivia together 

 (included within the southwestern portion of the same province) pos- 

 sess about 90 species, of which more than half are peculiar. North- 

 ward and northeastward from the " focal center" the number of species 

 diminishes gradually, Central America (including Guatemala) having 

 about 70 species (40 peculiar), Mexico, alone, about 50 (28 peculiar), 

 Venezuela, (including Trinidad and Tobago) between 50 and GO (15 pecu- 

 liar), Guiana about 36 (12 peculiar), and the West Indies with only 

 18 (all of them peculiar). 



* For example, among Humming Birds four species of the genus Selaspliorus and 

 one each of Eugenes, Doricha, Eupherusa, and Cceligena, and others related to or identical 

 with more northern forms. It is true a much larger numher of southern types occur 

 in the same country, but they are mainly restricted to lower and therefore more 

 tropical elevations. 



