POLIOPTILA. 67 



POLIOPTILA, SCLATEK. 



Polioptila, ScLATER, Pr. Zool. Soc. 1855, 11. (Type Motacilla caerulea, L.) 



Since the note on this genus was published by Mr. Sclater, in 1855, 

 enumerating four species, their number has greatly increased, as at 

 the present time at least nine or ten may be considered as perfectly 

 well established, possibly more. The species are very closely allied, 

 and can only be readily distinguished by an examination of the 

 males. In all the upper parts are plumbeous gray ; the under white, 

 more or less tinged with plumbeous. The tail feathers black, with 

 the outer three or four more or less varied with white ; the quills 

 black ; the primaries edged with ashy, the secondaries with white. 

 The males all have black on the head ; either the whole hood is black, 

 or else gray, with a narrow line of black margining it above the eye, 

 or a broad line through the eye. 



The following synopsis may aid in determining the males of the 

 different species of American Polioptila : — 



Whole top of head above black. 

 No white between eye and bill or above it. 



Outer tail feather black, except on outer web and extreme 

 tip (about one-sixth or seventh). Hub. Rio Grande 

 and Gila ......... melanura. 



Outer tail feather white, except portion hidden by under 

 tail coverts. Second feather white for terminal third ; 

 outline of white oblique, or along the fibres of the 

 feather. Tarsus, .75 ; tail, 2.20. Hab. N. W. Mexico nigriceps. 

 Outer tail feather black at base, but with more white than 

 last ; outlines of white directly transverse. Tarsus, 

 .69 ; tail, 2.45. Hab. Brazil ..... leucogastra. 



Outer tail feather entirely white ; 2d and 3d white nearly 



to base. Hab. Guiana and New Grenada . . buffoni. 



Lores white ; eyelids black. 



Outer tail feather black at the base. Hab. Central Amer. albiloris. 

 Lores and short supra-ocular stripe white. 



Inner web of outer tail feather white almost to base ; next 

 with basal third black ; this color extending little 

 further on the inner than the outer web. Hab. Panama superciliaris. 

 Inner web of outer tail feather black for basal third ; next 

 with basal half black : this color extending much 

 more on inner than outer web. Size considerably 

 larger. Hab. Carthageiia bilineata. 



Sides of head black : top <jray. 

 Under parts plumbeous, lighter than back. Hab. Eastern La 



Plata States dumicola. 



Under parts white, tinged with plumbeous. Hab. Bolivia . boliviana. 



