CiTAP. I. (.COLOURS OF TROPICAL INSECTS. 19 



the European Nemeobius Lucina. The Para insect, 

 however, belongs to a genus far removed in all essential 

 points of structure from Nemeobius ; namely, to Le- 

 Ki^onias, being the L. epulus. It is worthy of note that 

 all the old-world representatives, both tropical and 

 temperate, of this beautiful family of butterflies belong 

 to the same group as the English Nemeobius Lucina ; 

 whilst the few species inhabiting North America belong 

 wholly to South American types. 



Facts of this kind, and there are many of them, 

 would seem to show that it is not wholly the 

 external conditions of light, heat, moisture, and so forth, 

 which determine the general aspect of the animals of 

 a country. It is a notion generally entertained that the 

 superior size and beauty of tropical insects and birds are 

 immediately due to the physical conditions of a tropical 

 climate, or are in some way directly connected with 

 them. I think this notion is an incorrect one, and that 

 there are other causes more powerful than climatal 

 conditions which affect the dress of species. To test 

 this we ought to compare the members of those 

 genera which are common to two regions ; say, to 

 Northern Europe and equinoctial America, and ascer- 

 tain which climate produces the largest and most 

 beautifully-coloured species. We should thus see the 

 supposed effects of climate on nearly-allied congeners, 

 that is, creatures very similarly organised. In the 

 first family of the order Coleoptera, for instance, 

 the tiger-beetles (Cicindelidse), there is one genus, 

 Cicindela, common to the two regions. The species 

 found in the Amazons Valley have precisely the same 



