coagulates it to rubber, which is made into round flat cakes. A
large tree, five feet in diameter, will yield when first cut about
twenty gallons of milk, each gallon of which makes two and a half
pounds of rubber. I was told that the tree recovers from the wounds
and may be cut again after the lapse of a few months; but several
that I saw were killed through the large Harlequin beetle
(Acrocinus longimanus) laying its eggs in the cuts, and the grubs
that are hatched boring great holes all through the trunk. When
these grubs are at work you can hear their rasping by standing at
the bottom of the tree, and the wood-dust thrown out of their
burrows accumulates in heaps on the ground below. The government
attempts no supervision of the forests: any one may cut the trees,
and great destruction is going on amongst them through the young
ones being tapped as well as the full-grown ones. The tree grows
very quickly, and plantations of it might easily be made, which
would in the course of ten or twelve years become highly
remunerative.

We left Castillo at daylight the next morning, and continued our
journey up the river. Its banks presented but little change. We saw
many tall graceful palms and tree ferns, but most of the trees were
dicotyledons. Amongst these the mahogany (Swietonia mahogani) and
the cedar (Cedrela odorata) are now rare near the river, but a few
such trees were pointed out to me. High up in one tree, underneath
which we passed, were seated some of the black congo monkeys
(Mycetes palliatus) which at times, especially before rain and at
nightfall, make a fearful howling, though not so loud as the
Brazilian species. Screaming macaws, in their gorgeous livery of
blue, yellow, and scarlet, occasionally flew overhead, and tanagers
and toucans were not uncommon.