INTRODUCTION xiii 



book," and I therefore assume that my readers 

 have already made themselves conversant with 

 that work. I would ask them to read with 

 some care Mr. Halford's opening remarks on 

 entomology, found on pages 213 to 227 of the 

 Handbook, as an elementary knowledge of the 

 subject will be found necessary in order to follow 

 the descriptions accompanying the plates in this 

 book, and only a few lines have been written 

 here on the general principles of entomology. 



The publication of this work, following so 

 closely along the lines of Mr. Halford's standard 

 books on the dry-fly, is bound to give rise to 

 occasions for comparison of these coloured re- 

 presentations of the living flies with the colours 

 of his thirty-three patterns. Possibly dis- 

 crepancies may be pointed out between them. 

 In anticipation of such criticism, I must ask 

 my readers to bear in mind that Mr. Halford's 

 patterns are based on the colours as seen from 

 the ventral side only of the insects, whereas in 

 this work the duns are shown mainly in profile, 

 and the spinners arranged with the dorsal side 

 uppermost. 



I will not detain the reader any longer, but 

 in conclusion must acknowledge my indebted- 

 ness to Mr. Halford for the great help he has 

 rendered in the production of this book, not cnly 

 with his friendly counsel, but also in the labcrious 

 task of proof-reading 1 and correction ; to Mr. 



1 On the death of Mr. Halford, after this manuscript was 

 set up in type, Mr. William Senior and the Rev. A. E. Eaton 

 most kindly undertook the task of reading through the proofs. 

 Their criticism and advice were invaluable, and I owe to both 

 these gentlemen my most grateful thanks. 



