INTRODUCTORY REMARKS. XIX 



there is yet much to be done in all the islands, though unquestionably 

 less in Madeira proper and Teneriffe (which have been comparatively 

 well ransacked) than in any of the remainder. The only ones which 

 I have not myself visited are the Salvages ; for although a landing 

 was attempted there by Mr. Gray and myself, from his yacht, in 

 January 1858, the sea was running so high at the time, and the 

 rocks are so dangerous, that we could not accomplish it, and had to 

 pass on to the Canaries. But their area (even combined) is very 

 small, and it can hardly be expected that many species will be found 

 on them. Still, the few that have been obtained from thence (hitherto 

 only by Mr. Leacock, of Funchal, and the Barao do Castello da Paiva) 

 I am bound to add are most interesting and significant ; and I can 

 but express a hope that some enterprising naturalist may yet arise to 

 take them specially in hand following the example of the Messrs. 

 Crotch, who so nobly investigated Gomera. 



Importance of accuracy. Before proceeding further, I may perhaps 

 be permitted to call attention to the paramount importance, in pre- 

 paring a Catalogue like the present one, of the most perfect truthful- 

 ness on the question of habitat. Hence it has been my endeavour to 

 use the greatest possible caution in filling up the lists of the separate 

 islands, and to admit no species into them which rested upon unre- 

 liable evidence. In the majority of cases where an insect has been 

 communicated to me with the name of an island appended to it which 

 I had reason to regard as loose and untrustworthy, I have preferred 

 the omission of the species from that island's fauna to the risk of a 

 possible error, seeing that a mere omission is but trifling, whereas 

 a fault of commission would place permanently upon record a serious 

 topographical blunder. If, in spite of this, however, I have in a very 

 few instances conceded a species to an island upon evidence which 

 did not completely satisfy me, it will be observed that these excep- 

 tional cases are always guarded either by a note of interrogation 

 or an express statement of the authority on which their insertion 

 depends. 



This absolute necessity for accuracy (on the subject of localities), 

 in a topographical enumeration, compels me to advert to the grievous 

 want of it displayed by several of my continental correspondents who 

 have from time to time forwarded to me their material. It is chiefly 

 from Paris that the specimens to which I now allude have been sent ; 

 and it really does appear as if the label " Teneriffe " was the only one, 

 for Canarian species, that ever suggested itself to our well-intentioned 



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