582 The Natural History 



common origin. The resemblance is not nearly so strongly 

 marked in insects, the reason obviously being, that this class 

 of animals are much more immediately dependent on vegeta- 

 tion and climate than are the more highly organized birds 

 and Mammalia. Insects also have far more effective means of 

 distribution, and have spread widely into every district favor- 

 able to their development and increase. The giant Ornithop- 

 terai have thus spread from New Guinea over the whole Ar- 

 chipelago, and as far as the base of the Himalayas ; while the 

 elegant long-hoi'ned Anthribidse have spread in the opposite 

 direction from Malacca to New Guinea, but owing to unfavor- 

 able conditions have not been able to establish themselves in 

 Australia. That country, on the other hand, has developed a 

 variety of flower-haunting chafers and Buprestidae, and num- 

 bers of large and curious terrestrial weevils, scarcely any of 

 which are adapted to the damp gloomy forests of New Guinea, 

 where entirely different forms are to be found. There are, 

 however, some groups of insects, constituting what appear to 

 be the remains of the ancient population of the equatorial 

 parts of the Australian region, which are still almost entirely 

 confined to it. Such are the interesting sub-family of longi- 

 corn coleoptera — Tmesisternitse ; one of the best-marked gen- 

 era of Buprestidae — Cyphogastra ; and the beautiful weevils 

 forming the genus Eupholus. Among buttei-flies we have the 

 genera Mynes, Hypocista, and Elodina, and the curious eye- 

 spotted Drusilla, of which last a single species is found in 

 Java, but in no other of the western islands. 



The facilities for the distribution of plants are still greater 

 than they are for insects, and it is the opinion of eminent bot- 

 anists, that no such clearly-defined regions can be marked out 

 in botany as in zoology. The causes which tend to diffusion 

 are here most powerful, and have led to such intermingling of 

 the floras of adjacent regions that none but broad and general 

 divisions can now be detected. These remarks have an im- 

 portant bearing on the problem of dividing the surface of the 

 earth into great regions distinguished by the radical differ- 

 ence of their natural productions. Such difference we now 

 know to be the direct result of long-continued separation by 

 more or less impassable barriers; and as wide oceans and 

 great contrasts of temperature are the most complete barriers 



