4 PREFACE 



publication of the paper was nearly coincident with its 

 author s death.' Memoirs 1 7-2 1 are a continuation of the 

 work on the Systematics of the Blattidae which made him 

 the leading authority on the group. The appearance of 

 the separate appendix is almost entirely due to his efforts ; 

 for out of its nine memoirs he contributed seven, all of 

 them upon his favourite Blattidae. I well remember, when 

 he was writing his account of the subfamilies (Appendix 1-5) 

 for Wytsman's ' Genera Insectorum ', how pleased he was at 

 the thought that they would appear at some future time in 

 a large 4to volume of Reports devoted to the Systematics 

 of the Orthoptera. The dream was not destined to be 

 fulfilled except as regard the first five subfamilies of the 

 Blattidae. What might have been may be realized by 

 studying these admirable monographs. 



The papers on bionomics are headed by (3) — Dr. Dixey's 

 second Presidential address to the Entomological Society 

 — ' Entomology and Evolution.' In 1908 Mr. Guy A. K. 

 Marshall published a criticism of Diaposematism or 

 Reciprocal Mimicry. For some years I have kept this 

 paper, hoping for the time to write a reply to some of the 

 arguments contained in it, but lately I have come to the 

 conclusion that for the present it is best to concentrate 

 attention on the accumulation of facts bearing on the 

 discussion. As it is impossible to know when 1 shall be 

 able to write on the subject, Mr. Marshall's paper is included, 

 as (4), in the present volume. Dr. Dixey's reply in the 

 Transactions of the Entomological Society (1908, p. 559) 

 ought to have followed (4), but some of the copies have 

 been mislaid and the appearance of the paper in a volume 

 of Hope Reports is therefore unfortunately postponed. 

 A brief statement on. the same subject by Dr. Dixey appears 

 in (5), under which number references to the account of the 

 discussion printed in Vol. VII of the Hope Reports will be 

 found in the Contents. 



