Java and Sumatra being much better known than those of Borneo; but the
ancient separation of Java as an island is well exhibited by the large
number of its species which are not found in any of the other islands.
It possesses no less than seven pigeons peculiar to itself, while
Sumatra has only one. Of its two parrots one extends into Borneo, but
neither into Sumatra. Of the fifteen species of woodpeckers inhabiting
Sumatra only four reach Java, while eight of them are found in Borneo
and twelve in the Malay peninsula. The two Trogons found in Java are
peculiar to it, while of those inhabiting Sumatra at least two extend to
Malacca and one to Borneo. There are a very large number of birds, such
as the great Argus pheasant, the fire-backed and ocellated pheasants,
the crested partridge (Rollulus coronatus), the small Malacca parrot
(Psittinus incertus), the great helmeted hornbill (Buceroturus
galeatus), the pheasant ground-cuckoo (Carpococcyx radiatus), the
rose-crested bee-eater (Nyctiornis amicta), the great gaper (Corydon
sumatranus), and the green-crested gaper (Calyptomena viridis), and
many others, which are common to Malacca, Sumatra, and Borneo, but are
entirely absent from Java. On the other hand we have the peacock,
the green jungle cock, two blue ground thrushes (Arrenga cyanea
and Myophonus flavirostris), the fine pink-headed dove (Ptilonopus
porphyreus), three broad-tailed ground pigeons (Macropygia), and many
other interesting birds, which are found nowhere in the Archipelago 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 Papilionidae or
swallow-tailed butterflies, whose large size and gorgeous colouring
has led to their being collected more frequently than other insects.
Twenty-seven species are known from Java, twenty-nine from Borneo, 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
Sumatra.. . .. 21 do. 20 species common to both islands.
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