Literary Notices. 395 



have been added to justify republication, even if that were not fully justified by the 

 authors' success in popularizing their work. There are few studies in natural his- 

 tory which combine such admirable accuracy of observation and description with 

 the charm of style which is found in this book. 



For several years the Peckhams have studied the behavior of the social and 

 solitary wasps with patience,intelligent scientific insight and devotion to truth. They 

 have done well to make the results of their labors accessible to the general reader, 

 as well as to the scientific student of animal behavior, by writing the book which 

 we have in hand. 



By far the greater part of the volume is devoted to accounts of the habits of dif- 

 ferent species of wasps, but a few experimental tests of the sense equipment of the 

 Vespas are mentioned in the first chapter. Experiments with colored card-boards 

 proved to the satisfaction of the authors that these wasps can discriminate the spec- 

 tral colors. Their tests are open to the objection that the influence of difference 

 in intensity was not excluded. It is quite possible, so far as one may judge from 

 the authors' account of their method, that the wasps responded to intensity dif- 

 ferences and not to colors. 



Other simple tests proved the existence of sensitiveness to chemicals (smell). 

 On the whole it seems fair to say that the value of the observations under natural 

 conditions which are described in the book far outweighs that of the few experi- 

 ments tried. The Peckhams are naturalists, in the best sense of the term, butthey 

 are not experimentalists in the study of animal behavior. 



Detailed accounts are given of the digging, stinging, cell-storing, cell-closing, 

 nest-finding and several other forms of activity of a number of different kinds of 

 wasps. The value of these descriptions is great because they are based upon a 

 number of observations, not upon a single occurrence of the act. 



The various forms of behavior exhibited by the wasps are classified by the 

 authors as instinctive and intelligent. Concerning the first of these classes, the 

 most important conclusion to which one is led by the materials of the book is that 

 acts of this type are far more variable than they are usually supposed to be. Few 

 indeed of those acts of the wasps which are by common consent called instinctive 

 occur in exactly the same way from time to time in either the individual or the species. 

 Indeed, there is such marked variability that the old definition of instinct seems 

 scarcely applicable. The Peckhams have rendered the science of animal behavior 

 an invaluable service in proving beyond question that well established instinctive 

 forms of reaction do vary even in the insects. If one were to select the most im- 

 portant contribution which the work of the authors has made to our knowledge 

 of animal behavior, undoubtedly this fact of the variability of instinctive acts would 

 be chosen. 



Individual differences appear strikingly not only in instinctive forms of behavior 

 but equally in intelligent acts. The individuals of the same species of wasp differ 

 markedly often in the accuracy, care, skill, and rapidity, with which they perform 

 a certain kind of act. These marks of individuality are indicative of intelligence. 

 Many of the most interesting and picturesque of the descriptions of the book deal 

 with individual peculiarities. The authors came to know intimately and to feel 

 attachments for the members of certain species of wasps because of their attractive 

 ways, their industry, patience, perseverance. 



