48 



insects is widely dissimilar *." Now, it is impossible to 

 read this account without being at once struck with two 

 primary considerations : first, that there must exist some 

 great peculiarity (apart from climate) in a region the 

 fauna of which is thus singularly constituted; and, 

 secondly, that latitude (however important it may be in 

 a comprehensive point of view) must exercise in this 

 case a very secondary influence, to allow of localities 

 separated only by the Straits of Magellan to present 

 differences thus extraordinary. 



Although so dissimilar in many respects, Madeira 

 and Tierra del Fuego have evidently much in common 

 as regards the conditions which they afford for the 

 increase of organic life. Mr. Darwin describes the latter 

 as " a mountainous region, partly submerged in the 

 sea." So is Madeira. He also adds, that it is " covered 

 to the water's edge with one dense, gloomy forest;" 

 that " to find an acre of level land in any part of the 

 country is most rare ;" and that " within the forest, the 

 ground is concealed by a mass of slowly putrefying 

 vegetable matter, which, from being soaked with water, 

 yields to the foot." Such was Madeira, in its normal 

 state f; and such it still is throughout a large district 



* Journal of Researches, p. 238. 



f That I may not be misunderstood by those of my readers who 

 conceive Madeira to be a kind of " arva beata," with the sky for 

 ever blue, and (as a consequence) an unclouded sun ; I would re- 

 peat, that I am not speaking of the vicinity of Funchal only (from 

 which the invalids, who resort thither for their health, almost 

 exclusively draw their deductions), but of Madeira, and, more- 



