PREFACE. vii 



the increasing proportion of unknown to known species the higher 

 we ascended : — 



It may possibly be inferred, from the comparatively large number 

 of beetles which were secured, that the Coleoptera much preponderate 

 over other orders of Insects upon the Great Andes of the Equator. 

 Such an opinion would, I think, be erroneous, though at the very 

 greatest heights they are possibly as numerous as all other insects put 

 together. Yet various Diptera range almost as high as the highest of 

 the Coleoptera, and I can count up 75 species of spiders which were 

 obtained at 9500 feet and upwards. At moderate elevations in Ecuador 

 — say 10-11,000 feet — spiders were apparently more numerous than 

 anything else, and at some localities, such, for example, as Machachi, 

 they swarmed in countless numbers. Few Hymenoptera were found 

 anywhere near the snow-line, and of this order it may be remarked 

 that some of the largest species are found towards the superior limit 

 of its range, which is an exception to the general rule.^ 



^ I strongly dissent from the statement made by the late Prof. James Orton (in 

 "Contributions to tlie Natural History of the Valley of Quito," in the American 



