aiAP XXXIX.] OF THE PAPUAN ISLANDS. 



581 



Tmesisterint^e ; one of tlie best-tnarked genera of Bupres- 

 tidiB— Cyphogastra ; and the beautiful wee%'ils forming the 

 gentis Eupliolns. Among butterflies we have the genera 

 My ties, Hypocista, and Elodina, and the curious eye- 

 fi potted Drusilla, of wliich last a single species is found in 

 Ja\'a, but in tio other of the western islands. 



The facilities for the distribution of plants are still 

 jrreater than they are for insects, and it is the opinion of 

 eminent botanists, that no such clearly-defined regions can 

 be marked out in botany as in zoology. The causes "vvhieh 

 tend to ditfusion are here most powerful, and have led to 

 such interniin*,ding of the floras of adjacent regions that 

 none but broad and general divisions can now be detected. 

 These remarks have an important bearing on the problem 

 of dividing the surface of the earth into great regions, dis- 

 tinguished by the mdical difference of their natm-al pro- 

 ductions. Such difference we now know to be the direct 

 result of long-continued separation by more or less im- 

 ])assable barriers ; and as wide oceans and great contrasts 

 of temperature are the most complete barriei-s to tlie 

 dispersal of all terrestrial forms of life, the primary 

 divisions of the earth should in the main serve for all 

 terrestrial organisms. Ho%vever various may be the effects 

 of climate, however unequal the means of distribution, 

 these will never altogether obliterate the radical efiects of 

 long- continued isolation; and it is my firm conviction, that 

 when the botany and the entomology of New Guinea and 

 the surrounding islands become as well known as are 

 their mammals and birds, these departments of nature 

 will also plainly indicate the radical distinctions of the 

 Indo-Malayau and Austro-Malayau regions of the great 

 Malay A rch i pelago. 



