4 TRAVELS AMONGST THE GREAT ANDES. 



tive of the numerous characteristic and common genera of the north or 

 south. Even the northern genera more or less alnnidantly found on 

 the Mexican highlands are absent. 



The species of Coleoptera collected at altitudes above 9000 feet 

 are about 100 in number. The majority of these are mountain repre- 

 sentatives of genera characteristic of the lower levels or the plains of 

 Tropical America, some of which genera {e.g. Colpodes, Silpha, Fhihni- 

 ihus, etc.) occur also in other parts of the world ; others {e.g. Anisofarsns, 

 PelmateUus, Flati/codia, Lcuco])ehi'.a, Trigonogenius, etc.) are American 

 genera, having Chilian or Antarctic affinities, whilst others, as far as 

 we at present know, are peculiar to the high Andes. One feature of 

 the Fauna is of great interest. It is the occurrence of apterous species 

 of genera which at lower levels are always winged ; of these Mr. 

 Whymper found two belonging to the genus Bembidium, and one, a 

 weevil, belonging to the genus Macrops. This apterous condition has 

 been dwelt upon by Darwin, as a significant characteristic of the 

 Coleoptera of lofty mountains and Oceanic Islands. All the species of 

 Bemhidinin found on the island of St. Helena are a})terous, forming a 

 distinct group within the genus. 



The butterfiies enumerated in this Appendix are nearly all species 

 of the Tropical American lowlands, or closely allied to them. The 

 exceptions are the few which were found fiying at elevations from 

 10,000 to 16,000 feet, viz. Pieiis Xavthodire, CoJius (dticola, and Colias 

 dimem, all three belonging to small groups of their respective genera 

 which occur at great altitudes throughout South America, and as far 

 south as Chili. The genera Erebia, Chionobas, Parnassius, Argynnis, 

 Epinephele and many others, so highly characteristic of the Faunas of 

 the North Temperate zone, or Chili, or both, and of high vertical 

 ranges, are ({uite absent. 



It seems to me a fair deduction from the facts here set forth that 

 no distinct traces of a migration during the lifetime of existing species, 

 from north to south, or vice versa, along the Andes, have as yet been 

 discovered, or are now likely to be discovered. It does not follow, 

 however, that the Darwinian explanation of the i)eculiar distribution of 



