1918.] Cape San Aiitoitio, Buenos Aijres. 391 



a well-built deep cup o£ dry fiue rootlets ; and in an ivy- 

 covered tree, twenty feet from the ground. This last was 

 an ill-concealed nest, loosely built of roots and grass-stalks, 

 string, wool, moss, lichen, thistledown, etc., with no special 

 lining, about six inches in diameter and four inches deep 

 (outside measurement;, rather shallow internally. 



The clutch varies in number from four or five to as many 

 as seven. The eggs are, again, thinner in the shell than those 

 of the two preceding species, and are also less glossy. There 

 is much variation in the colour of the clutches. Possibly the 

 commoner type is I'cpresented by a pink ground-colour, 

 spotted and marked equally all over with red and dark 

 reddish brown, similar to, though not so bold, as in M. rufo- 

 axillaris. Another clutch is of a white ground colour 

 boldly marked and blotched with dull reddish brown, in- 

 creasing at the blunt end. A third is dirty greyish, spotted 

 and blotched all over with pale brown. Yet another is 

 merely whitish, densely maiked with reddish brown. 

 Measurements: 24x18mm. 



The iris in the adult is dark brown. 



97. Agelaeus thilius (Mol.). Yellow-shouldered Marsh- 

 bird. 



Mr. Hudson has again anticipated nearly all my ob- 

 servations. 



For a Marsh-bird, this species shows a marked proclivity 

 for the vicinity of buildings, and is also always to be found 

 at the oflfal where the daily slaughter of cattle and sheep 

 takes place. The larger flocks have sometimes a number 

 of the Yellow-breasted Marsh-bird (Pseudoleistes virescens) 

 associated with them. 



The nesting- season is from late in October to early in 

 December, most of the nests being found in November. 

 They are placed generally in a dry flag-bed in a swamp 

 (where they are sometimes abundant), or more rarely in a 

 clump of " Junquillo negro. ^^ In both these cases they are 

 either simply '' lodged " in, or attached to, their dense sur- 

 roundings, and about a foot to two feet from the ground. 



SEH. X. — VOL. VI. 2 F 



