PREFACE. 



FOR some years, much of my leisure time has 

 been devoted to the study of the anatomy, develop- 

 ment, and habits of the Annulosa, and especially of 

 Insects, on which subjects I have published various 

 memoirs, chiefly in the Transactions of the Royal, 

 Linnsean, and Entomological Societies : of these 

 papers I subjoin a list. Although the details, of 

 which these memoirs necessarily for the most part 

 consist, offer little interest, excepting to those per- 

 sons who are specially devoted to Entomology, 

 still there are portions which, having reference to 

 the nature of metamorphoses and to the origin of 

 insects, are of a more general character. I have 

 also briefly referred to these questions in a Mono- 

 graph of the Collembola and Thysanura, recently 

 published by the Ray Society, and in the Opening 

 Address to the Biological Section of the British 

 Association at Brighton in 1872. Under these 



