v SOCIAL HOMES 197 



ties say of one that it is not composed of wood fibres, 

 but of the dung of the Capincha, one of the aquatic 

 cavies of the region. One's attention is instantly 

 attracted to the fairly conical knobs or tubercles* with 

 which the surface is thickly beset, of various size, and 

 most pointed where they are least exposed. Their 

 disposition is in horizontal zones, seeming to corre- 

 spond more or less with the comb-tiers. While at the 

 top of the nest they are comparatively few, gradually 

 the numbers increase towards the lower end, and on 

 the bottom they are so numerous that one's finger can 

 scarcely be laid between them. Like the envelope 

 they are made up of several papery layers so closely 

 blended as to be hardly distinguishable, forming a sub- 

 stance astonishingly thick, hard, and firm, in colour 

 of a dull dark brown, and of very coarse texture. 

 Of what use they are it is difficult to decide ; 

 they may be simply freaks of nature. Although 

 their tips are not acute, they may defend the abode 

 against the attacks of tigers, jaguars, kuguars, and 

 other mammalia partial to honey and the grubs of the 

 hive. The nest always hangs low, seldom more than 

 three or four feet from the ground, and protection 

 would appear much needed. It seems hardly possible 

 to deny that they are for the double purpose 

 of concealing and of sheltering the entrances, 

 which are invisible when the nest is looked at 

 from above. Examination reveals them beneath a 

 row of the projections, which overhang them and 

 keep off* the rains like the eaves of a house ; the 

 passages are also intricately twisted, so as to prevent 

 the ingress of moths or other enemies of any size. It 



