250 TEOCHILID^. 



A few words on the classification of the Family seena necessary, as the system adopted 

 differs in many points from any hitherto promulgated. So various are the characters 

 possessed by the Trochilidse that hardly any serve to divide the Family into large 

 groups of genera ; the form of the bill, the modifications of the tail, all vary to such a 

 degree that they cannot be used except in a subordinate sense. A plan has been 

 adopted which is no doubt somewhat artificial in its application : this takes the 

 serration of the bill as a character by which to divide the whole Family into three 

 sections. In some genera these serrations are very plainly visible, in others no trace 

 of them can be seen, whilst in others they are very feeble and can only be traced with 

 difficulty. Out of these three states three sections have been formed, dividing the 

 Family into three subequal groups of genera : we do not call them Subfamilies as 

 they can hardly have so high a value placed upon them. The application of this 

 character brings several genera into a not unnatural proximity, and introduces a decided 

 improvement in the system of arrangement. Thus Hemistephania stands near Androdon, 

 Thalurania not far from Chlorostilbon, Avocettula next to Lampornis. Pinarolcema 

 proves to belong to the same neighbourhood, and not to that of OreotrocMlus. Even 

 Loddigesia is not unnaturally associated with Bellona and Cephalolepis. All these 

 points are in favour of the system here adopted and seem to justify its trial. 



As the structure of the Trochilidae has been very fully described in systematic works 

 on ornithology, and their habits have also been recorded in the many special works on 

 this favourite family, we do not propose to enter at length upon either subject here. 



We are much indebted to Mr. Ridgway for a complete list of the Mexican and 

 Central- American Trochilidae contained in the United States National Museum. All 

 the localities he gives us not previously published are quoted in the following pages. 



TEOCHILI. 



Sect. A. TROCHILI SERRIROSTRES. 



Tomia maxillce ad apicem distincte serrata ; mandilula quoque eodem modo 



scepe serrata. 



a. Eostrum cuneatum, ad basin latum, apicem versus gradatim compressum. 



HELIOTHRIX. 



Heliothrix, Boie, Isis, 1831, p. 547 ; Salv. Cat. Birds Brit. Mus. xvi. p. 30. 



A genus of three species, though others have been suggested. These are distributed 

 over the greater part of the forest regions of Tropical America, from British Honduras 

 and Eastern Guatemala to South Brazil, One species, E. larroti, occurs within our 

 region and spreads southwards to Western Ecuador. 



