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PARA 



sented by handsomer species in Amazonia than in Northern 

 Europe. Three others (Lycsena, Mehtaea and Apatura) 

 yield far more beautiful and larger forms in England 

 than in the Amazonian plains ; as to the remaining two 

 (Pamphila and Pyrgus) there is scarcely any difference. 

 There is another and hitherto neglected fact which I 

 would strongly press upon those who are interested in 

 these subjects. This is, that it is almost always the 

 males only which are beautiful in colours. The brilliant 

 dress is rarely worn by both sexes of the same species : 

 if climate has any direct influence in this matter, why 

 have not both sexes felt its effects, and why are the males 

 of genera living under our gloomy English skies adorned 

 with bright colours ? 



The tropics, it is true, have a vastly greater total 

 number of handsome butterflies than the temperate 

 zones ; but it must be borne in mind that they contain 

 a far greater number of genera and species altogether. 

 It holds good in all families that the two sexes of the 

 more brilliantly-coloured kinds are seldom equally beauti- 

 ful ; the females being often quite obscure in dress. 

 There is a very large number of dull-coloured species in 

 tropical countries. The tropics have also species in which 

 the contrast between the sexes is greater than in any 

 species of temperate zones ; in some cases the males 

 have been put in one genus and the females in another, 

 so great is the difference between them. There are 

 species of larger size, but at the same time there are 

 others of smaller size in the same families in tropical 

 than in temperate latitudes. If we reflect on all these 

 facts, we must come to the conclusion, that climate, to 

 which we are naturally at first sight inclined to attribute 

 much, has little or no direct influence in the matter. 

 Mr. Darwin was led to the same conclusion many years 

 ago, when comparing the birds, plants, and insects of the 

 Galapagos islands, situated under the equator, with those 

 of Patagonia and Tropical America. The abundance of 

 food, the high temperature, absence of seasons of ex- 

 treme cold and dearth, and the variety of stations, all 

 probably operate in favouring the existence of a greater 

 number and variety of species in tropical than in temperate 

 latitudes. This, perhaps, is all we can say with regard 

 to the influence of climatal conditions. The causes which 

 have produced the great beauty that astonishes us, if we 



