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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 Oxypeltus, have no close allies in any part
of the world. Holoptertis, though very peculiar, shows most re-
semblance to a New Zealand insect. Sibylla, Adalhus, and
Fhantagoderus, have Australian affinities ; while Calydon alone
shows an affinity for north-temperate forms. One species of the
northern genus, Leptitra, is said to have been found at Buenos
Ayres.
The Lamiidse are less abundant. Nine of the genera are Neo-
tropical. Two (Apomecyna and Exocentrus) 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 Lamiidse ex-
hibit Australian affinities, although these are a prominent fea-
ture in the relations of the Cerambycidse.
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 Carabidse, 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 Carabidse,
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