My collection of butterflies was not large; but I obtained some rare
and very handsome insects, the most remarkable being the Ornithoptera
Brookeana, one of the most elegant species known. This beautiful
creature has very long and pointed wings, almost resembling a sphinx
moth in shape. It is deep velvety black, with a curved band of spots of
a brilliant metallic-green colour extending across the wings from tip to
tip, each spot being shaped exactly like a small triangular feather, and
having very much the effect of a row of the wing coverts of the Mexican
trogon, laid upon black velvet. The only other marks are a broad
neck-collar of vivid crimson, and a few delicate white touches on the
outer margins of the hind wings. This species, which was then quite new
and which I named after Sir James Brooke, was very rare. It was seen
occasionally flying swiftly in the clearings, and now and then settling
for an instant at puddles and muddy places, so that I only succeeded in
capturing two or three specimens. In some other parts of the country I
was assured it was abundant, and a good many specimens have been sent
to England; but as yet all have been males, and we are quite unable to
conjecture what the female may be like, owing to the extreme isolation
of the species, and its want of close affinity to any other known
insect.
One of the most curious and interesting reptiles which I met with in
Borneo was a large tree-frog, which was brought me by one of the Chinese
workmen. He assured me that he had seen it come down in a slanting
direction from a high tree, as if it flew. On examining it, I found the
toes very long and fully webbed to their very extremity, so that when
expanded they offered a surface much larger than the body. The
forelegs were also bordered by a membrane, and the body was capable of
considerable inflation. The back and limbs were of a very deep shining
green colour, the undersurface and the inner toes yellow, while the
webs were black, rayed with yellow. The body was about four inches long,
while the webs of each hind foot, when fully expanded, covered a surface
of four square inches, and the webs of all the feet together about
twelve square inches. As the extremities of the toes have dilated
discs for adhesion, showing the creature to be a true tree frog, it is
difficult to imagine that this immense membrane of the toes can be for
the purpose of swimming only, and the account of the Chinaman, that it
flew down from the tree, becomes more credible. This is, I believe, the
first instance known of a "flying frog," and it is very interesting to
Darwinians as showing that the variability of the toes which have been
38