18/2.] HABITS OF THE VIZCACHA. 825 



bo favourable to two of our birds tbat they are among the most 

 common species found here, whereas without these burrows they 

 would have been exceedingly rare, since the natural banks in which 

 they breed are scarcely found any where on the pampas. I refer to 

 the Minera (Geositta cunicularia), which makes its breeding-holes 

 in the bank-like sides of the Vizcacha's burrow, and to the little 

 Swallow (Afticora cyanoleuca) which breeds in these excavations 

 when forsaken by the Minera. Few old vizcacheras are seen without 

 some of these little parasitical burrows in them. 



Birds are not the only beings in this way related to the Vizcachas : 

 the Fox and the Weasel of the pampas live almost altogether 

 in them. Several insects also frequent these burrows that are sel- 

 dom found anywhere else. Of these the most interesting are : — a 

 large predacious nocturnal bug, shining black, with red wings ; a 

 nocturnal Cicindela, a beautiful insect, with dark green striated 

 shards and pale red legs ; also a genus of diminutive wingless Wasps. 

 Of the last I have counted six species, most of them marked 

 with strongly contrasted colours, black, red, and white. There are 

 also other Wasps that prey on the Spiders found on the vizcachera. 

 All these and others are so numerous on the mounds that dozens of 

 them might there be collected any summer day ; but if sought for in 

 other situations they are exceedingly rare. If the dry mound of soft 

 earth which the Yizcacha elevates amidst a waste of humid, close- 

 growing grass is not absolutely necessary to the existence of all these 

 species, it supplies them with at least one favourable condition, and 

 without doubt thereby greatly increases their numbers : they, also, 

 whether predacious or preyed on, have so many relations with other 

 outside species, and these again with still others, that it would be 

 no mere fancy to say that probably hundreds of species are either 

 directly or indirectly affected in their struggle for existence t>y the 

 vizcacheras so abundantly sprinkled over the pampas. 



In winter the Vizcachas seldom leave their burrows till dark, but 

 in summer come out before sunset ; and the vizcachera is then 

 a truly interesting spectacle. 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. When approached from the 

 front he stirs not, but eyes the intruder with a bold indifferent stare. 

 If the person passes to one side, he deigns not to turn his head. 



Other Vizcachas soon begin to appear, each one quietly taking up 

 his station at his burrow's mouth, the females, known by their greatly 

 inferior size and lighter grey colour, sitting upright on their haunches, 

 as if to command a better view, and indicating by divers sounds and 

 gestures that fear and curiosity struggles in them for mastery ; for 

 they are always wilder and sprightlier in their motions than the 

 males. With eyes fixed on the intruder, at intervals they dodge 

 the head, emitting at the same time an internal note with great 

 vehemence ; and suddenly, as the danger comes nearer, they plunge 

 simultaneously, with a startled cry, into their burrows. But in some, 

 curiosity is the strongest emotion ; for, in spite of their fellow's conta- 

 gious example, and already half down the entrance, again they start 



