166 Bulletin American Museum of Natural History. [Vol. XXXVI, 



Hemispingus superciliaris nigrifrons Agelaius icterocephalus bogotensis 



Pseudospingus verticalis >-^ Sturnella magna meridionalis 



"Urothraupis stolzmanni Microglseus subalaris 



Psittospiza riefferi riefferi p^^^ily Corvida 



Family Icteridm Cyanolyca armillata armillata 



Cacicus leuoorhamphus " " quindiuna 



The Paeamo Zone. 



The name 'Paramo' is locally applied to any treeless region lying above 

 10,000 feet. Thus, the road from Bogota to Chipaque is commonly said 

 to pass over the Paramo of Boqueron whereas, f aunally, it nowhere extends 

 above the Temperate Zone. 



The true Paramo Zone extends from the upper limit of trees to the lower 

 limit of snow. On Santa Isabel, in the Central Andes, Allen and Miller 

 found this zone between the altitudes of 12,500 and 15,200 feet, but where 

 the upper border of the Temperate Zone is arid and lacking in forest the 

 paramo appears to reach a lower level. Thus, on the range east of Bogota, 

 the mullein-like 'frailejon' so characteristic of the Paramo Zone, grows 

 abundantly at 11,000 feet, and some plants of this species are found even 

 lower. 



Where, however, on peaks which do not rise to snow-line, humid condi- 

 tions prevail, the tree-line may reach 13,000 feet and the lower level of the 

 Paramo Zone be correspondingly higher. 



Miller and Boyle reached this altitude on the Paramillo, the .highest 

 point in the Western Andes, but found there but few species which may be 

 considered as representative of this zone, including Orodynastes striaticoUis 

 striaticollis. We have elsewhere found this bird only on the Paramo of 

 Santa Isabel, but I observe that Bangs records it from an altitude of 8000 

 feet in the Santa Marta group, and it possibly may not be a true Paramo 

 Zone form. 



Conditions on the Paramillo seem favorable for the presence of species 

 which are common on Santa Isabel, and their absence can only be attribut- 

 able to the isolation of this peak and may be considered to indicate that at 

 no time has it been connected with areas having the life of the Paramo 

 Zone. This zone in its full development is therefore, apparently absent in 

 the Western Andes. 



In the Central Andes it occurs in at least twelve places between the 

 Paramos of Las Pappas and Santa Isabel. Both these localities were 

 visited by our expeditions (Nos. 3 and 4) and Allen's careful description of 

 the country traversed should be read in this connection. 



