114 TRAVELS AMONGST THE GREAT ANDES. chap. v. 



light bodies are borne upwards. . . . When Bonpland, Carlos Montufar 

 and myself reached, on the 23rd of June, 1802, on the eastern declivity 

 of the Chimborazo the height of 19,286 English feet, we saw winged 

 insects fluttering around us. We could see that they were Dipteras, but 

 ... it was impossible to catch the insects. . . . The insects were flying 

 at a height of about 18,225 feet. . . . Somewhat lower down, at about 

 2600 toises (16,680 feet), also therefore within the line of perpetual 

 snow, Bonpland had seen yellow butterflies flying very near the ground." 



The aim and intention of this passage is to shew that insects 

 are transported invohmtarily to great altitudes, and this un- 

 questionably often occurs. Most persons who have travelled 

 in mountainous regions have found, at one or another time, in 

 very elevated situations (sometimes on snow or glacier), insects 

 which, from their known habits and habitats, cannot have domi- 

 ciled themselves on the spot ; ^ and their actual transportation 

 in quantities, in ascending currents of air, has occasionally been 

 witnessed. But it would be erroneous to assume that insect-life 

 in the neighbourhood of tiie snow-line in Equatorial America is 

 limited to stragglers, or that they form a considerable percentage 

 of it. The upper zones of the Great Andes have a residential 

 population,^ and I shall endeavour to shew, at a later point, 

 that the '^yellow butterfly,^ which Humboldt uses to give point 

 to his remarks, probably comes within the category of ' perma- 

 nent residents ' ; and, if it does, it is not a happy example of a 

 wind-borne straggler. 



At first, the dimensions of the great basin of Machachi were 

 underrated or unappreciated. Objects which were supposed to be 

 a mile distant sometimes proved to .be two or three miles away. 

 Woods looked like clumps of bushes, and impassable ravines 

 appeared mere ditches. When we became better acquainted 

 with it, the bare, almost naked-looking j^lain was found to 



^ Examples are given in Chapters VI., XIII., and XV. 



^ In the Supp. App. there will be found 98 species of insects which were 

 taken at 10,000 feet and upwards. Of these, 15 are known, 71 are new to science, 

 and 12 are not identified. 



