INTRODUCTION 



No one who has devoted any considerable part of 

 his open-air leisure to the observation of living 

 insects can fail to be struck by the fact that each 

 species has its own definite method of life, its own 

 way of doing things, and, in the construction of a 

 shelter for itself or its progeny, its own preference 

 for materials and its own mode of using them. 

 These are the methods and preferences not of the 

 individual, but of the species ; and the individual 

 needs no apprenticeship, but goes directly to work 

 with the experience it has inherited from an enorm- 

 ously long line of ancestors. In an earlier period of 

 our civilization the son followed the vocation of 

 his father, taught by him, and inheriting the 

 secrets of the craft. Many of our surviving sur- 

 names are due to this fact, the names of Smith, 

 Taylor, Fletcher, Bowyer, and the like becoming 

 permanently attached to the families pursuing these 

 crafts and mysteries. In the case of the Insects, 

 the parents cannot instruct their offspring, for as 

 a rule they never see them. One marvels at the 

 skill displayed by the bird in constructing its first 

 nest ; but it may be said that the newly mature 

 bird has at least a chance of watching a second- 

 year matron of its kind building, and getting some 

 hints that way. In the case of the Insects there is, 

 as a rule, no possibility of such help. In the vast 



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