DWELLINGS. l6S 



trenches, making an acute or right angle converging 

 into the first trench, so that the whole when com- 

 pleted takes a Y shape. These trenches are con- 

 tinually deepened and lengthened in this manner, 

 the angular segment of earth between them being 

 scratched away, until by degrees it gives place to one 

 large deep irregular mouth. The burrows are made 

 best in the black and red moulds of the pampas ; but 

 even in such soils the entrances may be varied. In 

 some the central trench is wanting, or so short that 

 there appear to be but two passages converging 

 directly into the burrow, or these two trenches may 

 be so curved inwards as to form the segment of 

 a circle. Usually, however, the varieties are only 

 modifications of the Y-shaped system. 



On the pampas a wide-mouthed burrow possesses 

 a distinct advantage over the more usual shape. The 

 two outer trenches diverge so widely from the mouth 

 that half the earth brought out is cast behind instead 

 of before it, thus creating a mound of equal height 

 about the entrance, by which it is secured from water 

 during great rainfalls, while cattle avoid treading over 

 the great pit-like entrances, though they soon tread and 

 break in the burrows of the Armadillo and other 

 species when these make their homes on perfectly 

 level ground. 



The Vizcachas do not usually leave their burrows 

 until dark, but in summer they come out before sun- 

 set. Usually one of the old males first appears, 

 and sits on some prominent place on the mound, 

 apparently in no haste to begin his evening meal. 

 Other Vizcachas soon begin to appear, each quietly 

 taking up his position at the burrow's mouth. The 

 ferriales, known by their smaller size and lighter 



