2 Mr. H. Eltringham's Monogra'pk of the 



now deemed too small or unimportant to be worthy 

 of record. We aim at minute and careful classification, 

 and though such classification is an artificial process of 

 segregation having convenience as its aim, it is based on 

 natural features, the study of which reveals those very 

 facts which can enlarge oxxy knowledge of nature's methods. 

 Such considerations indicate the desirability of carefully 

 compiled monographs of natural groups, and of such works 

 there are, fortunately, many splendid examples. To 

 students of the Lepidoptera the publications of Messrs. 

 Rothschild and Jordan have furnished an example of 

 perfection, which others may well find difficult of imita- 

 tion ; but those who, like the present writer, are conscious 

 of a lesser capacity for achievement, may at least en- 

 deavour to follow, to the best of their ability, the path 

 which has been thus so fully indicated. 



To the comfort of those who would undertake such 

 labours, naturalists are ever ready to place at each other's 

 disposal, the resources which they individually possess, and 

 it is thus that the pleasant duty devolves iipon me of 

 thanking most sincerely the many friends who have fur- 

 nished me with material and assistance. It has been my 

 privilege to carry out the present work under ideal con- 

 ditions provided by the kindness of Professor Poulton in 

 the Hope Department at Oxford, Avhere I have had the 

 free use of the whole of the vast store of material there 

 accumulated. To him also I am indebted for kindly 

 reading portions of the proofs, and for many valuable sug- 

 gestions. Mr. Walter Rothschild Iims generously placed the 

 whole of his collection of Acraeas at my disposal, not only 

 for examination, but also for dissection and anatomical 

 study. The authorities of the Natural History Museum 

 at South Kensington have allowed me to make microscopic 

 preparations from many valuable duplicates, and I am also 

 deeply indebted to many other collectors and workers 

 amongst whom I would especially m'ention Mr. G. T. 

 Bethune-Baker, Dr. F. A. Dixey, Mr. G. C. Dudgeon, Mr. 

 Herbert Druce, Mr. H. H. Druce, Mr. C. J. Grist, Mr. 

 J. J. Joicey, Dr. Karl Jordan, Mr. G. A. K. Marshall, 

 Mr. S. A. Neave, Miss E. M. Bowdler Sharpe, Mr. Roland 

 Trimen, and Commander J. J. Walker. 



Continental authorities have been no less generous in 

 their assistance, and permission was granted me to work 

 through the whole of the large collection in the Berlin 



