X PREFACE 



separately and in most cases some important member of the 

 family is described in greater detail. As far as possible the 

 description of the infections immediately follows that of the 

 family concerned in their transmission. Thus the account of 

 the Psychodidae and Phlebotonius is succeeded by a chapter 

 devoted to Pappataci Fever (Three Day Fever), whilst the 

 account of Malaria follows that of the AnopheHnse. Certain 

 difficulties have arisen in the case of diseases (e.g. trypano- 

 somiasis) transmitted by members of more than one family, 

 but such infections have been described in connection with 

 their more important carrier. At the end of each chapter are 

 given a few references to the literature on the subject, but it 

 should be emphasised that the bibliography is not in any 

 way complete, but merely contains the titles of publications 

 that will be of assistance to students requiring detailed in- 

 formation in any particular branch. The present edition 

 does not profess to deal with works published later than 

 the beginning of 1913, although in isolated cases it has been 

 found possible to include references to later work. 



The writer has great pleasure in acknowledging the 

 extremely valuable assistance which he has received from 

 Major S. R. Christophers, I. M.S., in the preparation of chapters 

 VIII and IX, devoted respectively to the classification of 

 the Culicidae, and an account of Malaria. These are almost 

 entirely the work of that distinguished authority and con- 

 sidering their importance in the present work, his name ought 

 to have appeared as a joint author. However, Major Christo- 

 phers would not consent to this arrangement and therefore 

 the author can only express his great indebtedness for this 

 generous help. 



For permission to reproduce illustrations, which had 

 previously appeared in other publications, and also for the 



