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. 



\ 



