COLOURS OF TROPICAL INSECTS 13 



flies, again, we saw a small species of Erycinidae flying 

 about low shrubs in grassy places, which was extremely 

 similar in colours to the European Nemeobius Lucina. 

 The Para insect, however, belongs to a genus far removed 

 in all essential points of structure from Nemeobius ; 

 namely, to Lemonias, 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 be- 

 long 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 ascertain which climate produces the largest 

 and most beautifully-coloured species. We should thus 

 see the supposed effects of climate on nearly-allied con- 

 geners, that is, creatures very similarly organized. 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 habits as their 

 English brethren, running and flying over sandy soils 

 in the bright sunshine. About the same number is found 

 in each of the two countries : but all the Amazonian 

 species are far smaller in size and more obscure in colour 

 than those inhabiting Northern Europe ; none being at 

 all equal in these respects to the common English Cicin- 

 dela campestris, the handsome light-green tiger-beetle, 

 spotted with white, which is familiar to country residents 

 of Natural History tastes in most parts of England. In 

 butterflies I find there are eight genera common to the 

 two regions we are thus pitting against each other. Of 

 these, three only (Papilio, Pieris and Thecla) are repre- 



