PDF - Wallace Online

CHAP. XXI.] INSECTS. 497
North Temperate zone. It must be remembered, however, that
in view of the immense geological antiquity of the existing
families of Beetles, dating back certainly to the Secondary and
probably to the Paleeozoic epoch, " comparatively recent " may
still be of considerable antiquity.
It is somewhat singular that North and South America have
no genera exclusively in common. The connection between
South America and Africa seems to be shown,—by the genus
Psiloptera, the mass of the species being divided between these
regions, with a few widely scattered over the globe ; and the
American genus Adenodes, which has one species in West
Africa. Somewhat allied, is the extensive genus Polyhoihris,
strictly confined to Madagascar. The genus Agrilus is perhaps
cosmopolitan, although no species of the family is recorded from
New Zealand. Among the peculiarities of distribution we may
notice,—the genus Sponsor, with 8 species in the island of
Mauritius, 1 in Celebes, and 1 in New Guinea ; Ptosima, scat-
tered between the United States, Mendoza in South Temperate
America, South Europe, the Philippine Islands, and North
China; Polycesta, which besides inhabiting South America,
North America, and Europe, has a single species in Madagascar
and Belionota, which has 8 species African, 8 Indo-Malayan, 2
Austro-Malayan, and 1 in California. The extensive genus
Acmceodera, is most abundant in the warm and dry portions of
the Palsearctic, Ethiopian, and Nearctic regions, with some in
the Andes and South Temperate America, a few in Brazil and
the West Indies, and 1 said to be from the Philippines. About
one-third of the genera (containing more than half the species)
have a tolerably extensive range, while the genera confined to
single regions contain only about one-fourth of the total number
of species.
It will, I think, be admitted, after a careful study of the
preceding facts, that the regions and sub-regions here adopted,
serve to exhibit, with great clearness, the chief phenomena of
distribution presented by this interesting family.
;
\