vi PREFACE 



of geographical distribution the authorities are too numerous 

 and scattered to admit of a list being given. 



A special word of thanks is due to Mr. Edwin Wilson for 

 his patient care in preparing the illustrations, the majority of 

 which are taken from specimens in the University Museum of 

 Zoology. Mr. Edgar Smith, besides affording the kind help 

 which visitors to the British Museum always experience at his 

 hands, has permitted me to use many specimens for the pur- 

 poses of illustration. 



A. H. COOKE. 



King's College, Cambridge, 

 20th December 1894. 



