284 ZOOLOGICAL GEOGRAPHY. [PART ILI. 
African genera; but Coptops is Oriental, and the Oriental 
Praonetha occurs in the Comoro Islands. Among the peculiar 
genera several have African affinities, but Tropidema belongs to 
a group which is Oriental and Australian ; Oopsis is found also 
in the Pacific Islands ; Mythergates, Sulemus, and Coedomea, are 
allied to Malayan He American genera. 
General Remarks on the Insect-fauna of Madagascar. —Taking 
the insects as a whole, we find the remarkable result that their 
affinities are largely Oriental, Australian, and South American: 
while the African element is represented chiefly by special 
South African or West African forms, rather than by such as 
are widely spread over the Ethiopian region’ In some 
families—as Cetoniide and Lamiide—the African element 
appears to preponderate ; in others—as Cicindelide—the South 
American affinity seems strongest; in Carabide, perhaps the 
Oriental; while in Buprestide and Cerambycide the: African 
and foreign elements seem nearly balanced. We must not im- 
pute too much importance to these foreign alliances among 
insects, because we find examples of them in every country on 
the globe. The reason they are so much more pronounced in 
Madagascar may be, that during long periods of time this island 
has served as a refuge for groups that have been dying out on 
the great continents; and that, owing to the numerous: de- 
ficiencies of a somewhat similar kind in the series of vertebrata 
in Australia and South America, the same groups have often 
been able to maintain themselves in all these countries as well 
as in Madagascar. It must be remembered too, that these pecu- 
liarities in the Malagasy and Mascarene insect-fauna are but ex- 
aggerations of a like phenomenon on the mainland. Africa also 
has numerous affinities with South America, with the Malay 
countries, and with Australia; but they do not bear anything like 
so large a proportion to the whole fauna, and do not, therefore, 
attract so much attention. The special conditions of existence 
and the long-continued isolation of Madagascar, will account for 
much of this difference ; and it will evidently not be necessary 
1 There are also some special resemblances between the plants of Mada- 
gascar and South Africa, according to Dr. Kirk. 
