CHAP. XIV.] 
THE NEOTROPICAL REGION. 
47 
altogether peculiar, but most of them are more or less closely 
allied to genera inhabiting Tropical America. Some, as the hand- 
some Chcloderus and Oxypdtus, have no close allies in any part 
of the world. Holopterus, though very peculiar, shows most re- 
semblance to a New Zealand insect. Sibylla, Adalhts, and 
Phantagoderus , have Australian affinities ; while Calydon alone 
shows an affinity for north-temperate forms. One species of the 
northern genus, Leptura, is said to have been found at Buenos 
Ayres. 
The Lamiidae are less abundant. Nine of the genera are Neo- 
tropical. Two (. Apomecyna and JExocentrus) are spread over all 
tropical regions. Ten genera are peculiar; and most of these 
are related to Neotropical groups or are of doubtful affinities. 
Only one, Aconopterus , is decidedly allied to a northern genus, 
Pogonochcerus. It thus appears, that none of the Lamiidae ex- 
hibit Australian affinities, although these are a prominent fea- 
ture in the relations of the Cerambycidae. 
It is evident, from the foregoing outline, that the insects of 
South Temperate America, more than any other class of animals, 
exhibit a connection with the north temperate regions, yet this 
connection is only seen in certain groups. In Diurnal Lepidop- 
tera and in Carabidae, the northern element is fully equal to the 
tropical, or even preponderates over it. We have already sug- 
gested an explanation of this fact in the case of the Carabidae, 
and with the butterflies it is not more difficult. The great mass 
of Neotropical butterflies are forest species, and have been de- 
veloped for countless ages in a forest-clad tropical country. The 
north temperate butterflies, on the other hand, are very largely 
open-country species, frequenting pastures, mountains, and open 
plains, and often wandering over an extensive area. These 
would find, on the higher slopes of mountains, a vegetation and 
conditions suited to them, and would occupy such stations in 
less time than would be required to adapt and modify the forest- 
haunting groups of the American lowlands. In those groups 
of insects, however, in which the conditions of life are nearly the 
same as regards both temperate and tropical species, the superior 
