284 ZOOLOGICAL GEOGRAPHY. [part hi. 



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 Coedomcea, are 

 allied to Malayan and 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. 1 In some 

 families — as Cetoniidse and Lamiidre — the African element 

 appears to preponderate ; in others — as Cicindelidce — the South 

 American affinity seems strongest ; in Carabidse, perhaps the 

 Oriental ; while in Buprestida3 and Cerambycidae 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. 



