132 Mr. C. H. B. Grant on Birds collected in Argentina , 
The young bird taken on February 10 is moulting very 
slightly and has one chestnut feather in the head. 
This Spine-tail frequents the rushes and reeds, where it 
creeps about after the manner of a Sedge-Warbler, and is 
not, as a rule, easy to shoot. 
I took three eggs at Ajo: the nest, a mere bedding of 
dead grass, being placed on the ground in a dry part of the 
swamp. 
120. Anumbius acuticaudatus. 
Anumbius acuticaudatus Scl. Cat. B. xv. p. 75 ; Arg. Orn. 
i. p. 189. 
a } b. A $ ad. Los Ynglases, Ajo. Sept. 12-Oct. 28,1908. 
c y d, e. B $ ad. & young. Los Ynglases, Ajo. Jan. 25- 
Mar. 23, 1909. 
Irides hazel; bill pale brown; legs and toes pale yel¬ 
lowish livid. 
Both the September and October birds are worn and faded. 
The February and March birds are in moult, the latter 
having almost completed it. 
The young bird is very similar to the adult, but is paler 
generally, especially below, and has much less chestnut on 
the forehead. 
This is a common resident in the Ajo district, and spends 
more of its time on the ground than in the trees. It has a 
clear and trilling note. 
The nest is a large structure of sticks, generally thorny, 
placed in a tree or bush, the hole being at the top, whence 
a zigzag tunnel leads down to the nest ; it is warmly lined, 
often along the whole length of the tunnel also, with wool. 
121. PflACELODOMUS RUFIFRONS. 
Phacelodomus rufifrons Scl. Cat. B. xv. p. 80. 
Phacellodomus frontalis Arg. Orn. i. p. 192. 
a, b. S ? ad. Puerto Maria, Paraguay. Oct. 24, 1909* 
Irides dark grey ; bill dark slate-coloured, lower man¬ 
dible ashy; legs and toes slate-coloured. 
