PREFACE. VU 



pleasure to find life-history so ably and philosophically 

 studied. It was so with the fathers of the science ; De Geer 

 and Reaumur have never been excelled, but for a long time 

 they had no disciples. Now we are all travelling the same 

 road. Smith with the bees ; Armistead with the gallflies ; 

 Stainton with the Microlepidoptera ; Crewe, Machin, Hellins 

 and Buckler with the Macrolepidoptera; and a host of others, 

 are watching the growth and changes of our caterpillars as 

 carefully as ever a fond mother watched the progress of her 

 children. It is thus, and thus only, that we can attain that 

 intimate knowledge of a species which enables us to write its 

 real history. 



In a companion Journal I am making an endeavour to 

 classify those phenomena which are usually comprehended 

 under the vague term " variation " : that I shall succeed en- 

 tirely I do not presume to hope, but I have already succeeded 

 in calling attention to a subject previously neglected; for 

 although a variety has aVays been acknowledged a variety, 

 it has been nothing more. It has never been studied as one 

 of a group of phenomena that required connection, classifica- 

 tion and explanation. I introduce the subject here only to 

 announce my object, and to say how glad I shall be of 

 assistance. 



I have also to ask the assistance of my brother entomolo- 

 logists in another cause. I have commenced an " Illustrated 

 Natural History of British Moths ; " with the exception of a 

 few of the Eupitheciae, which are either so small, so obscure, 

 or so like cognate species, as to defy the ability of an artist 

 to distinguish them, each moth, so far at least as the termi- 

 nation of the Macrolepidoptera^ will be represented of the 



