CHAP. V.

LONGICORN BEETLES.

209

of trees (Coptodera, Goniotropis, Morio, &c.), others running over the slender twigs, branches, and leaves (Ctenostoma, Lebia, Calophæna, Lia, &c.), and many were concealed in the folds of leaves (Calleida, Agra, &c.). Most of them exhibited a beautiful contrivance for enabling them to cling to and run over smooth or flexible surfaces, such as leaves. Their tarsi or feet are broad, and furnished beneath with a brush of short stiff hairs, whilst their claws are toothed in the form of a comb, adapting them for clinging to the smooth edges of leaves, the joint of the foot which precedes the claw being cleft so as to allow free play to the claw in grasping. The common dung-beetles at Caripí, which flew about in the evening like the Geotrupes, the familiar "shardborne beetle with his drowsy hum" of our English lanes, were of colossal size and beautiful colours. One kind had a long spear-shaped horn projecting from the crown of its head (Phanæus lancifer). A blow from this fellow, as he came heavily flying along, was never very pleasant. All the tribes of beetles which feed on vegetable substances, fresh or decayed, were very numerous. The most beautiful of these, but not the most common, were the Longicornes; very graceful insects, having slender bodies and long antennæ, often ornamented with fringes and tufts of hair. They were found on flowers, on trunks of trees, or flying about the new clearings. One small species (Coremia hirtipes) has a tuft of hairs on its hind legs, whilst many of its sister species have a similar ornament on the antennæ. It suggests curious reflections when we see an ornament like the feather of a grenadier's cap situated on one part of the

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body in one species, and in a totally different part in nearly allied ones. I tried in vain to discover the use of these curious brush-like decorations. On the trunk of a living leguminous tree, Petzell found a number of a very rare and handsome species, the Platysternus hebræus, which is of a broad shape, coloured ochreous, but spotted and striped with black, so as to resemble a domino. On the felled trunks of trees, swarms of gilded-green Longicornes occurred, of small size (Chrysoprasis), which looked like miniature musk-beetles, and, indeed, are closely allied to those well-known European insects.

I was interested in the many small kinds of lignivorous or wood-eating insects found at Caripí, a few observations on which may be given in conclusion. It is curious to observe how some small groups of insects exhibit the most diversified forms and habits-one set of species being adapted by their structure for one set of functions in nature, and another set, very closely allied, for an opposite sphere of action. Thus the Histerida-small black beetles well known to English entomologists, most of whose species are short and thick in shape and live in the dung of animals—are most diversified in structure and habits in the Amazons region; nevertheless, all the forms preserve in a remarkable degree the essential characters of the family. One set of species live in dung; most of these are somewhat cubical in shape, the head being retractable within the breastplate, as in the tortoise. Another group of Histerida are much flatter in form, and live in the moist interior of palm-tree stems; one

CHAP. V.

DEPARTURE FROM CARIPÍ.

211

of these is a veritable colossus, the Hister maximus of Linnæus. A third group (Hololeptæ) are found only under the bark of trees; their heads are not retractable within the breast, and their bodies are excessively depressed, to fit them for living in narrow crevices, some kinds being literally as thin as a wafer. A fourth set of species (Trypanææus) form a perfect contrast to these, being cylindrical in shape. They drill holes into solid wood, and look like tiny animated gimlets when seen at work, their pointed heads being fixed in the wood whilst their smooth glossy bodies work rapidly round, so as to create little streams of sawdust from the holes. Several families of insects show similar diversities of adaptation amongst their species, but none, I think, to the same extent as the Histerida, considering the narrow limits of the group. The facts presented by such groups in the animal kingdom must be taken into account in any explanation of the way the almost infinite diversity of the forms of life has been brought about on this wonderful earth.

At length, on the 12th of February, I left Caripí, my Negro and Indian neighbours bidding me a warm adeos." I had passed a delightful time, notwithstanding the many privations undergone in the way of food. The wet season had now set in; the low lands and islands would soon become flooded daily at high water, and the difficulty of obtaining fresh provisions would increase. I intended, therefore, to spend the next three months at Pará, in whose neighbourhood there was still much to be done in the intervals of fine weather, and then start off on another excursion into the interior.

CHAPTER VI.

THE LOWER AMAZONS-PARÁ TO OBYDOS.

Modes of Travelling on the Amazons-Historical Sketch of the early Explorations of the River-Preparations for Voyage-Life on board a large Trading-vessel-The narrow Channels joining the Pará to the Amazons-First Sight of the great River-Gurupá-The Great Shoal-Flat-topped Mountains-Contraction of the River ValleySantarem--Obydos-Natural History of Obydos-Origin of Species by Segregation of Local Varieties.

AT the time of my first voyage up the Amazonsnamely, in 1849-nearly all communication with the interior was by means of small sailing vessels, owned by traders residing in the remote towns and villages, who seldom came to Pará themselves, but entrusted vessels and cargoes to the care of half-breeds or Portuguese cabos. Sometimes, indeed, they risked all in the hands of the Indian crew, making the pilot, who was also steersman, do duty as supercargo. Now and then, Portuguese and Brazilian merchants at Pará furnished young Portuguese with merchandise, and despatched them to the interior to exchange the goods for produce amongst the scattered population. The means of communication, in fact, with the upper parts of the Amazons had been on the decrease for some time, on account of the augmented difficulty of obtaining hands

CHAP. VI.

TRADE-WIND OF THE AMAZONS.

213

to navigate vessels. Formerly, when the Government wished to send any important functionary, such as a judge or a military commandant, into the interior, they equipped a swift-sailing galliota, manned with ten or a dozen Indians. These could travel, on the average, in one day further than the ordinary sailing craft could in three. Indian paddlers were now, however, almost impossible to be obtained, and Government officers were obliged to travel as passengers in trading vessels. The voyage made in this way was tedious in the extreme. When the regular east wind blew-the "vento geral," or trade wind, of the Amazons-sailing vessels could get along very well; but when this failed they were obliged to remain, sometimes many days together, anchored near the shore, or progress laboriously by means of the "espia." This latter mode of travelling was as follows. The montaria, with twenty or thirty fathoms of cable, one end of which was attached to the foremast, was sent ahead with a couple of hands, who secured the other end of the rope to some strong bough or tree trunk; the crew then hauled the vessel up to the point, after which the men in the boat re-embarked the cable, and paddled forwards to repeat the process. In the dry season, from August to December, when the trade-wind is strong and the currents slack, a schooner could reach the mouth of the Rio Negro, a thousand miles from Pará, in about forty days; but in the wet season, from January to July, when the east wind no longer blows and the Amazons pours forth its full volume of water, flooding the banks and producing a tearing current, it took three months to