PREFACE. IX 



1864 between Teneriffe, Gomera, and Hierro, returning, as 

 indeed might have been anticipated from collectors so accu- 

 rate and indefatigable, with a goodly booty. I will not ven- 

 ture to speculate on the number of specimens which they 

 amassed ; but it must have been more than half that of my 

 own, which I estimated (ore rotundo] at 20,000. The species 

 of course were not nearly so numerous as those which I my- 

 self met with for they were obtained in only three islands, 

 whereas mine were from the whole seven ; nevertheless their 

 researches were beyond all expectation successful for, in 

 addition to swelling out very considerably the local lists of 

 the particular islands which they visited (as will be seen by a 

 reference to the pages of this treatise), they increased the 

 entire fauna by actually 77 species which had not until then 

 been detected in the Canarian archipelago. 



I will now only add that, whilst recording with gratitude 

 the assistance I have received, in different ways, from nume- 

 rous friends and correspondents, during the several years 

 which have elapsed since my Atlantic labours were com- 

 menced, my especial acknowledgements are due, first, 



To the Rev. R. T. Lowe who has been my constant com- 

 panion, since 1847, whilst encamping in many distant Ma- 

 deiran localities, and sojourning (at intervals) in the various 

 islands of both Groups, and without whose aid and local 

 advice I could scarcely have attempted any general and con- 

 tinuous work ; secondly, 



To John Gray, Esq., in whose yacht c the Miranda ' I first 

 visited the Canaries a widely scattered archipelago, which, 

 in all probability, I should never have explored had it not 

 been for his liberality and zeal ; and lastly, 



To the Messrs. Crotch whose invaluable and well-directed 

 researches have been made to supplement my own with such 



