i867— 1882] WALLACE'S BOOK 19 



where a varied fauna now exists, have been once more Letter 393 

 extensive — e.g., New Zealand, Madagascar: where there is 

 no such evidence {e.g., Galapagos , the fauna is very restricted. 



Lastly, as to want of references : I confess the justice of 

 your criticism ; but 1 am dreadfully unsystematic. It is my 

 first large work involving much of the labour of others. I 

 began with the intention of writing a comparatively short 

 sketch, enlarged it, and added to it bit by bit ; remodelled 

 the tables, the heading, and almost everything else, more 

 than once, and got my materials in such confusion that it 

 is a wonder it has not turned out far more crooked and 

 confused than it is. I, no doubt, ought to have given 

 references ; but in many cases I found the information so 

 small and scattered, and so much had to be combined and 

 condensed from conflicting authorities, that I hardly knew 

 how to refer to them or where to leave off. Had I referred 

 to all authors consulted for ever}' fact, I should have greatly 

 increased the bulk of the book, while a large portion of the 

 references would be valueless in a few years, owing to later 

 and better authorities. My experience of referring to re- 

 ferences has generally been most unsatisfactory. One finds, 

 nine times out of ten, the fact is stated, and nothing more ; 

 or a reference to some third work not at hand ! 



I wish I could get into the habit of giving chapter and 

 verse for every fact and extract ; but I am too lazy, and 

 generally in a hurry, having to consult books against time, 

 when in London for a day. 



However, I will try to do something to mend this matter, 

 should I have to prepare another edition. 



I return you Forel's letter. It does not advance the 

 question much ; neither do I think it likely that even 

 the complete observation he thinks necessary would be of 

 much use, because it may well be that the ova, or lar\ . 

 or imagos of the beetles are not carried systematically by 

 the ants, but only occasionally, owing to some exceptional 

 circumstances. This might produce a great effect in distri- 

 bution, yet be so rare as never to come under observation. 



Several of your remarks in previous letters I shall 

 carefully consider. I know that, compared with the extent 

 of the subject, my book is in many parts crude and 

 ill-considered ; but I thought, and still think, it better to 



