PREFACE XI 



loan of the original blocks, I am indebted to the following: 

 the Publisher (G. Fischer) and Editors of the Archiv fur 

 Protistenkunde, for permission to reproduce Fig. 87; the 

 Editor of the Bulletin of Entomological Research for the loan 

 of the blocks of Figs. ^18, 19, 59-61, 67, 73 and 74 ; the President 

 and Fellows of the Cambridge Philosophical Society for the 

 loan of the block of Fig. 57 ; the Editors of the Journals of 

 Pamsitology and Hygiene for the block of Fig. 41 and permis- 

 sion to reproduce Figs. 4, 8, 25, 26, 27, 29 and 31 ; the Director 

 of the Tropical Diseases Bureau for the loan of the blocks of 

 Figs. 42-45 and 65; Dr P. H. Bahr and Messrs Witherby 

 and Co. for the loan of the blocks of Figs. 54 and 56 ; Maclure, 

 Philips and Co. for permission to reproduce Figs. 46, 47 and 49. 

 Dr E. Roubaud for the loan of the blocks of Figs. 62, 64, 

 66, 68, 70, 76-78 ; Dr G. S. Graham-Smith for the loan of the 

 blocks of Figs. 1-3 and 82 and 83 ; Professor G. H. F. Nuttall 

 for permission to reproduce Figs. 30, 32 and 55 ; Surgeon- 

 General Sir David Bruce for permission to reproduce Figs. 

 79 and 80; and Miss Muriel Robertson for permission to 

 reproduce the drawings from which Fig. 75 was constructed ; 

 Mr Edwin Wilson, F.E.S., kindly prepared the drawing of the 

 stridulating organ of Anopheles (Fig. 28). 



It is the author's pleasant duty to return thanks for the 

 assistance afforded by these gentlemen. 



In conclusion, I should like to express the great debt I owe 

 to Professor G. H. F. Nuttall, who by his friendly criticism and 

 helpful suggestions has lightened the author's labours and 

 also prevented many serious omissions. 



E. H. 



September, 1914. 



