Paraguay, Bolivia , and Southern Brazil: 85 
This exceedingly graceful and pretty species is by no 
means common in the montes in the Ajo district, but is 
resident, being observed throughout the twelve months. 
It is seen singly, in pairs, or occasionally three or four 
together, creeping about among the upper branches of the 
Tala trees after the manner of our Long*tailed Titmouse 
(Acredula caudata ), and its note is very similar to that of the 
Blue Titmouse (Farm cceruleus). Its flight as it goes from 
tree to tree is dipping and graceful. 
There is little doubt that it breeds in this district, though 
I did not find the nest or even see the birds carrying building 
material; but towards the close of the summer of 1908-1909 
I saw one or two parties of old and young. 
6. Donacobius atricapillus. 
Donacobius atricapillus Sharpe, Cat. B. vi. p. 364 ; Arg. 
Orn. i. p. 13. 
a. $? ad. Boca de Homiguera, Brazil. Oct. 9, 1909. 
Irides rich yellow; bill black, ashy on under side of lower 
mandible; bare skin on side of neck lemon-chrome ; legs 
and toes dark ashy. 
Many individuals were observed frequenting the long grass 
at the edges of the swamps. 
7. Troglodytes hornensis. 
Troglodytes hornensis Sharpe, Cat. B. vi. p. 257. 
Troglodytes musculus hornensis Oberhols. Proc. U.S. Nat. 
Mus. xxvii. p. 203. 
a. ad. Los Ynglases, Ajo. 
b, c, d. <$ ? ad. „ „ 
e,f. <J ? ad. & yg. 
g. S ad. 
h. $ ad. 
i. ? young. 
j. ? young. 
Sept. 16, 1908. 
Oct. 18-26,1908* 
Jan. 21-25,1909. 
Feb. 3, 1909. 
Mar. 10,1909. 
Jan, 7, 1910. 
Feb. 2, 1910. 
Ad. Irides hazel; bill dark brown, lower mandible livid 
flesh-coloured ; gape yellow; legs and toes pale brown. 
The adult specimens vary slightly individually,, but there 
