50 ZOOLOGY OP THE VOYAGE OF THE BEAGLE. 



This bird, like the last species, generally moves in very small flocks. Its 

 habits, I presume, are also very similar ; for I state in my notes that it closely 

 approaches to our tit-mice in general manners and appearance. 



3. Serpophaga nigricans. Gould. 



Sylvia nigricans, Vieill. 



Tachuris nigricans, D'Orbig. fy Lafr. Mag. de Zool. 1837. p. 55. 



Le Petit Tachuris noiratre, Azara, No. 167. 



This bird is common in the neighbourhood of Maldonado, on the banks of the 

 Plata. It generally frequents the borders of lakes, ditches, and other moist 

 places ; but is related in its general manners with the last species. It often 

 alights on aquatic plants, growing in the water. When seated on a twig it occa- 

 sionally expands its tail like a fan. 



Sub.-Fam.— TITYRANjE. (Psarianjs, Sw.) 

 Pachyramphus, G. R. Gray. 



Pachyrhynchus, Spix. 



1. Pachyramphus albescens. 



Pacliyrliynchus albescens, Gould, MS. 

 Plate XIV. 



P. olivaceo-griseus ; alis nigrescenti brunneis, albescenti marginatis ; gutture corpore- 

 que subtus griseo-albis ; alarum tectricibus inferioribus pallide sulphureis. 



Long. tot. 5-^2 unc. ; alee, 2 T L ; caudw, 2^- ; tarsi, f-% ; rost. ^. 



Head and all the upper surface olive grey ; wings blackish brown, the coverts 

 and secondaries broadly margined with dull white ; primaries narrowly 

 margined with greyish white ; tail blackish brown, the external web of the 

 outer feather white; under surface of the shoulder pale sulphur yellow; 

 throat and under surface greyish white ; bill and feet black. 



Habitat, Buenos Ayres. 



The generic name of Pachyrhynchus Spix, is changed by Mr. G. R. Gray, 

 to Pachyramphus, as the former word is used in entomology. 



