Indo-Malay Islands. 157 



eater (Nyctiornis araicta), the great gaper (Cory don suma- 

 tranus), and the green-crested gaper (Calyptomena vh'idis), 

 and many others, which are common to Malacca, Sumatra, 

 and Borneo, but are entirely absent from Java. On the oth- 

 er hand we have the peacock, the green jungle-cock, two blue 

 ground-thrushes (Arrenga cyanea and Myophonus flaviros- 

 tris), the fine pink-headed dove (Ptilonopus porphyreus), 

 three broad-tailed ground-pigeons (Macropygia), and many, 

 other interesting birds, which are found nowhere in the Archi- 

 pelago out of Java. 



Insects furnish us with similar facts wherever sufficient 

 data are to be had, but owing to the abundant collections 

 that have been made in Java, an unfair preponderance may 

 be given to that island. This does not, however, seem to be 

 the case with the true Papilionidse, or swallow-tailed butter- 

 flies, w^hose large size and gorgeous coloring has led to their 

 being collected more frequently than other insects. Twenty- 

 seven species are known from Java, twenty-nine from Bor- 

 neo, and only twenty-one from Sumatra. Four are entirely 

 confined to Java, while only two are peculiar to Borneo and 

 one to Sumatra. The isolation of Java will, however, be best 

 shown by grouping the islands in pairs, and indicating the 

 number of species common to each pair. Thus : 



Borneo 29 species ) „„ . i. u i.u • i j 



^ > 20 species common to both islands. 



[20 do. do. do. 



f™^*'"^ 21 do. )^j ^^ ^^_ ^^_ 



Java 2/ do. 5 



Making some allowance for our imperfect knowledge of 

 the Sumatran species, we see that Java is more isolated from 

 the two larger islands than they are from each other, thus 

 entirely confirming the results given by the distribution of 

 birds and Mammalia, and rendering it almost certain that 

 the last-named island was the first to be completely separa- 

 ted from the Asiatic continent, and that the native tradition 

 of its having been recently separated from Sumatra is entire- 

 ly without foundation. 



We are now enabled to trace out with some probability 

 the course of events. Besrinnino: at the time when the whole 



Sumatra 21 do 



Borneo 29 do. 



Java 27 do. 



