PREFACE. 



This volume had its inception in a series of eight lectures delivered 

 at Columbia University during the spring of 1905, and represents, in a 

 much condensed form, the results of a decade of uninterrupted study 

 of the Formicidse, and of the works that have been written on these 

 insects. 



If an excuse were required for its publication, one might be found 

 in the fact that for many years no comprehensive treatise on the ants 

 has appeared in the English language. This may be regarded as a 

 reproach to English and American zoologists, since during all this time 

 almost the only active contributors to myrmecology were to be found 

 on the European continent. It must be admitted, however, that the 

 methods of publication adopted by continental writers have not been 

 such as to attract the attention of English-speaking students, since their 

 works have not only been issued in a variety of languages French, 

 German, Swedish, Italian, Russian, etc. but also in a great number 

 of often very obscure, local or inaccessible journals and proceedings 

 of learned societies. Moreover, most of the continental observers 

 within recent years have been too busy with special lines of investi- 

 gation to publish compendia on myrmecology. It thus happens that 

 although ants are our most abundant and most conspicuously active 

 insects, they have not, till very recently, received any serious attention 

 from American systematists, and the descriptions of most of our 

 species must still be sought in a lot of more or less fragmentary 

 foreign contributions. 



My work began in an endeavor to increase our systematic knowl- 

 edge of the North American ants, but I was fascinated by the activities 

 of these insects and soon saw the advantage of studying their taxonomy 

 and ethology conjointly. This method, which was, indeed, unavoid- 

 able, has greatly retarded the appearance of the present work, for it 

 was impossible to write about the behavior of many of our most inter- 

 esting forms till their taxonomic status had been definitely settled. On 

 the other hand, I could find no satisfaction in devoting all my energies 

 to collecting and labelling specimens without stopping to observe the 

 many surprising ethological facts that were at the same time thrusting 

 themselves upon my attention. My observations have now covered so 

 much of our fauna that I shall soon be able to publish a systematic 



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