PREFACE. ix 



It has been, of course, impossible to describe the introduced 

 species, or to quote many of the references to them ; for other- 

 wise this book would have become inordinately long. For the 

 same reason I have for the most part contented myself with 

 a list of the myrmecophiles (other insects, etc.) found with 

 each species of ant. At some future date I hope to write a 

 companion volume entirely devoted to the British myrmecophilous 

 fauna. 



A list as complete as I have been able to make it of the 

 literature dealing with British ants is printed at the end of the 

 book. This list also includes papers on myrmecophiles, as from 

 these latter I have largely obtained information on the distribu- 

 tion of their ant-hosts. Other notes on ants contained in papers 

 on Hymenoptera, and Entomology generally, will be found in the 

 references under each species. 



It may be stated that I have personally verified every reference 

 given in this book. In catalogues, such as Dalla Torre's, etc., 

 dealing with vast accumulations of literature, it is impossible to 

 guard against occasional errors, which are unfortunately copied 

 again and again, and sometimes increased by mistakes in the 

 copying. I can only hope that by much pains I myself have erred 

 as little as possible in this direction. 



I must thank most of our Entomologists for kindly sending me 

 ants to name, and allowing me to see their captures. I am deeply 

 indebted to Mr. J. H. Durrant, the Rev. F. D. Morice, and Pro- 

 fessor E. B. Poulton for kind encouragement and assistance, 

 Professor E. A. Minchin for dissections of the internal structure, 

 Mr. E. A. Elliott for translations from the Danish and Swedish, 

 and Mrs. Mellor for her kindness in collating and type- writing the 

 Pilot-files, card-indexes, etc., in connection with my extensive 

 myrmecological library. 



The following account of twenty years of labour and experience 

 has been brought to a conclusion during the opening months of a 

 supreme national crisis wellnigh within sound of the guns. At 

 such a time it is too much to hope or even to wish that the problems 

 of biological science should receive their due meed of attention. 

 But later on, when the success of which we cannot be doubtful 

 shall have attended our efforts and those of our Allies, when in- 

 tellectual pursuits have resumed their sway, it is hoped that the 



