TEOCHILID^. 249 



Order MACROCHIRES. 



Suborder TROCHILI. 

 Fam. TROCHILID^. 



This purely Neogefen Family of birds contains, according to the most recently 

 prepared catalogue, about 470 species, which are divided into 127 genera. Of tliese 

 no less than 118 species, belonging to 50 genera, occur within the limits of Central 

 America and Mexico. By far the larger number of these inhabit the more tropical 

 portion of the country, the number of species becoming less as the northern frontier is 

 approached, and, on the other hand, they are more numerous both in species and 

 genera in the mountainous parts of Costa Eica and the State of Panama. Thus, in 

 Northern Mexico we can only record 14 species, while in Costa Rica and Panama we 

 know of the existence of no less than 65, Southern Mexico possessing 48, and Guate- 

 mala 38. Though the Trochilidse are thus fully represented in our country, there 

 are still a very considerable number of genera, mostly belonging to the Andes, not 

 found within our limits. They include some of the most remarkable forms of the 

 Family : thus we do not find any representative of Biphlogoena, HeUanthea, or Bourci- 

 eria, nor Cijanolesbia, Sappho, or Lesbia, Heliangelus or Urosticte, and many other 

 brilliant forms. Nor do any of the characteristic genera of the higher Andes occur, 

 such as Oreotrochilus, Oreonympha, Bhamphomicron, Oxypogon, Agloeactes, or Erio- 

 cnemis. Nevertheless our region has 20 genera belonging to it, none of which are 

 found in the southern continent : these are lache, Phceoptila, Microchera, Callipharus, 

 Eupherusa, Elvira, Panterpe, Arinia, Basilinna, Sphenoproctus, Phceochroa, Eugenes, 

 Cceligena, Oreopyra, Delattria, Lamprolcema, AbeilUa, Tilmatura, Calothorax, and 

 Atthis. This is a much larger proportion of genera peculiar to our region than is 

 found in any other group of birds, and is due in a great measure to the treatment the 

 Trochilidse have received as regards the subdivision of genera, which has been carried 

 further than in any other Family of birds. At the same time it must be noted that 

 this very remarkable group, so specialized as a whole, is very highly differentiated 

 as regards its species, and the genera, numerous as they are, do no more than link 

 together the most obviously allied forms. If any considerable reduction of their 

 number were attempted, the result would hardly prove satisfactory, as the uniformity 

 of many genera would scarcely fail to suffer thereby. In fact many more genera than 

 the number here accepted have been proposed, so that the present system is a com- 

 promise between the extreme views held on this point. 



BIOL. CENTR.-AMEK., Aves, Vol. II., May 1892. 32 



