PEE FACE. 



Tcadera will naturally ask why I have delayed 

 writing this book for six years after my return ; and 

 I feel bound to give tlieni full satisfaction on this point, 



Wlien T reached England in the spring of 1862, I found 

 myself surrounded by a room full of packing- oases, con- 

 taining the collections that I had from tiiue to time sent 

 home for my private use. These coraprised nearly three 

 thousand bii'd-skins, of about a thousand species ; and at 

 least twenty thousand beetles and butterflies, of about 

 seven thousand species; besides some quadrupeds and 

 land-shells, A large proportion of these I had not seen 

 for years; and in my then weak state of health, the 

 unpacking, sorting, and arranging of such a mass of 

 specimens occupied a long time. 



I very soon decided, that until I had done something 

 towards naming and describmg the most important groups 

 in my collection, and had worked out some of the more 

 interesting problems of variation and geographical distri- 

 bution, of which I had had glimpses while collecting tlium, 

 I would not attempt to publish my travels, 1 could, 

 indeed, at once have printed my notes and journals, 

 leaving all reference to questions of natural history for a 

 future work; hut I felt that this would be as unsatis- 

 factory to myself, as it would be disappointing to my 

 friends, and nninstructive to the public. 



Since my return, up to tliis date, I have published 

 eighteen papers, in the Transactions or Proceedings of the 



