in Zoologiccil and Botanical Chography. 11 



Other orders of insects auJ other families of Coleoptera 

 may very probably give somewhat different results. From 

 Boheman's work on the Cassididae, I find that tlie genera of 

 tropical America send representatives into Chili, and even 

 into Patagonia, and that none of the south temperate forms 

 have a direct affinity with those of Australia. But this 

 family is almost exclusively tropical, very few and obscure 

 species inhabiting the colder regions of tlie earth, while 

 there are no generic forms peculiar to the Australian region. 



In many of the preceding facts we have a most in- 

 teresting correspondence with those furnished by the distri- 

 bution of plants. Dr Hooker has show^n the large amount 

 of resemblance between the flora of southern South America 

 and Australia, especially Tasmania and New Zealand,— one- 

 eighth of the whole New Zealand flora being identical with 

 South American species. Again, the occurrence of north- 

 ern genera of coleoptera in Chili, and the whole of the 

 butterflies having northern affinities, agrees with the number 

 of northern genera and species of plants in Patagonia and 

 Fuegia, and is an additional proof of the intensity and long 

 continuance of the glacial epoch which sufficed to allow so 

 many generic forms to pass the equator from north to south. 



We have here another illustration how much easier of 

 diffusion, and how much more dependent on local condi- 

 tions are insects than the higher animals. A great part of 

 the southern portion of America is of more recent date than 

 the central tropical mass, and must have had at one time a 

 closer communication than at present with the antarctic 

 lands and Australia, the insects and plants of which, finding 

 a congenial climate, established themselves in the new 

 country, being only feebly opposed by the few northern 

 forms which had already, or soon after, migrated there. And 

 the fact that Tasmania and New Zealand are the poorest 

 (countries in the world in butterflies, will enable us to under- 

 stand how it is that all those found in Chili are northern 

 forms, while the coleoptera of the same countries (Tas- 

 mania and New Zealand) being tolerably abundant and 

 varied, and having a shorter journey to perform than the 

 north temperate immigrants, were enabled to get the upper 

 hand in colonizing the new country. 



