134 INSTINCT AND KEASON. 



of construction, protection, repair, vary. The same occurs 

 in birds or other animals still of the same species 

 inhabiting different parts of the same country, or different 

 and distant parts of the world. For instance, artificial are 

 sometimes preferred to natural nests, materials, or sites ; 

 man's refuse wool, hair, tow man's dwelling, even his 

 prepared artificial nests, are selected, rather than those 

 materials and localities that were or are made use of by 

 the species when at a distance from man and his works. 

 Such variations in nidification are obviously determined, 

 more or less, by various specific motives, purposes, or cir- 

 cumstances, such as necessity or desirability, or the saving of 

 trouble, or the love of society, or the desire for protection, or 

 by conditions of climate or temperature, or they are the 

 results of experience and knowledge. The art of building 

 fire-proof nests, moreover, is an acquisition on the part of the 

 swallow. 



Birds, however, are not the only animals that modify the 

 character of their nests according to circumstances. A cer- 

 tain trap-door spider of New Zealand, as has been recently 

 pointed out by Gillies, according to conditions of soil, loca- 

 lity, and surroundings, ' constructs an entirely different type 

 of nest.' It shows, he says, an ' adaptation to special cir- 

 cumstances as they arise ; ' and he describes it as conceal- 

 ing its nest in an ( endless variety of ways,' the materials 

 being * as numerous and various as nature or accident has 

 provided in the neighbourhood.' The commoner so-called 

 ' geometric ' spider also varies the construction of its nest 

 (Blackwall). The nest of the same species of wasp is some- 

 times differently constructed, according to the locality, the 

 cause, however, not always being apparent (Kouget). 



Even less liable to modification than the operations of 

 birds, constructive or other, are popularly supposed to be 

 those of the bee. And yet Huber tells us that in some of 

 his experiments humble-bees, in the absence of the usual 

 material for roofing their nests, tore up linen clothes, or the 

 cover of a book, and carded the disintegrated material into a 

 felted mass, for use as an efficient substitute ; while he gives 

 many instances of their ' variety of resource .... in adapting 



