72 



Annals of the Carnegie Museum. 



Microrhopias intermedia 

 Sakesphorus pulchellus 

 Myiarchus tyrannulus tyrannulus 

 Elania gaimardii bogotensis 

 PhcBomyias tenuirostris 

 Euscarthmus impiger 

 Mimus gilvus columhianus 



PoliopHla plumbiceps 

 Heleodytes minor albicilius 

 Pachysylvia aurantiifrons auran- 



tiifrons 

 Ccereba luteola luteola 

 Cacicus cela 

 Thraupis glaucocolpa 



Some of the above we know do not range westward beyond the 

 semi-arid region of the northeast coast, as for instance Microrhopias 

 intermedia, which is replaced in the lower Magdalena Valley by a 

 distinct species, Microrhopias alticincta hondce; Cacicus cela, which 

 is similarly replaced by Cacicus vitellinus; and Eleenia gaimardii bogo- 

 tensis, replaced by Elania gaimardii macilvainii. (See Figure 2.) 



Fig. 2. Range of Microrhopias intermedia (i), a species of the Arid Trop- 

 ical Zone which enters the Santa Marta Region from the east, but is replaced 

 in the Magdalena Valley by an allied form, M : alticincta honda (2). 



The presumption is strong, therefore, that the species in this list have 

 reached their present range in the littoral of Colombia by extending 

 their range 'westward along the coast,' some having gone farther 

 than others. At any rate, few of these forms are yet known from the 



