The Naturalist on the River Amazons

In the lower part of the Mahicd woods, towards the river, there is a bed of stiff white clay, which supplies the people of Santarem with material for the manufacture of coarse pottery and cooking utensils; all the kettles, saucepans, mandioca ovens, coffee-pots, washing-vessels, and so forth, of the poorer classes throughout the country, are made of this same plastic clay, which occurs at short intervals over the whole surface of the Amazons valley, from the neighbourhood of Para to within the

Peruvian borders, and forms part of the great Tabatinga marl deposit. To enable the vessels to stand the fire, the bark of a certain tree, called Caraipé, is burnt and mixed with the clay, which gives tenacity to the ware. Caraipé is an article of commerce, being sold, packed in baskets, at the shops in most of the towns. The shallow pits, excavated in the marly soil at Mahica, were very attractive to many kinds of mason bees and wasps, who make use of the clay to build their nests with. I spent many an hour watching their proceedings; a short account of the habits of some of these busy creatures may be interesting.

The most conspicuous was a large yellow-and-black wasp, with a remarkably long and narrow waist, the Pelopzeus fistularis. It collected the clay in little round pellets, which it carried off, after rolling them into a convenient shape, in its mandibles. It came straight to the pit with a loud hum, and on alighting, lost not a moment in beginning to work; finishing the — kneading of its little load in two or three \ minutes. The nest of this species is shaped like a pouch, two inches in length, and is attached to a branch or other projecting object. One of these restless artificers once began to build on the handle of a chest in the cabin of my canoe, when we were stationary at a place for several days. It was so intent on its work that it allowed me to inspect the movements of its mouth with a lens whilst it was laying on the mortar. Every fresh pellet was brought in with a triumphant song, which changed to a cheerful busy hum when it alighted and began to work. The little ball of moist clay was laid on the edge of the cell, Pelopzeus Wasp building nest. and then spread out around the circular rim, by means of the lower lip guided by the mandibles. The insect placed itself astride over the rim to work, and, on finishing each addition to the structure, took a turn round, patting the sides with its feet inside and out before flying off to gather a fresh pellet. It worked only in sunny weather, and the previous layer was sometimes not quite dry when the new coating was added. The whole structure takes about a week to complete. T left the place before the gay little builder had quite finished her task: she did not accompany the canoe, although we moved along the bank of the river very slowly. On opening closed nests of this species, which are common in the neighbourhood of Mahica, I always found them to be stocked with small spiders of the genus Gastracantha, in the usual half-dead state to which the mother wasps reduce the insects which are to serve as food for their progeny.

Besides the Pelopzeus there were three or four kinds of Trypoxylon, a genus also found in Europe, and which some Naturalists have supposed to be parasitic, because the legs are not furnished with the usual row of strong bristles for digging, characteristic of the family to which it belongs. The species of Trypoxylon, however, are all building wasps: two of them which I observed (T. albitarse and an undescribed species)

provision their nests with spiders, a third (T. aurifrons) with small caterpillars. Their habits are similar to those of the Pelopzeus: namely, they carry off the clay in their mandibles, and have a different song when they hasten away with the burthen, from that which they sing whilst at work. Trypoxylon albitarse, which is a large black kind, three quarters of an inch in length, makes a tremendous fuss whilst building its cell. It often chooses the walls or doors of chambers for this purpose, and when two or three are at work in the same place their loud humming keeps the “Ss. house in an uproar. The cell is a tubular structure about three inches in

Cells of Trypoxylon aurifrons. length. T. aurifrons, a much smaller species, makes a neat little nest shaped like a carafe; building rows of them together in the corners of verandahs.

But the most numerous and interesting of the clay artificers are the workers of a species of social bee, the Melipona fasciculata. The Meliponz in tropical America take the place of the true Apides, to which the European hive-bee belongs and which are here unknown; they are generally much smaller insects than the hive-bees, and have no sting. The M. fasciculata is about a third shorter than the Apis mellifica; its colonies are composed of an immense number of individuals. The workers are generally seen collecting pollen in the same way as other bees, but great numbers are employed gathering clay. The rapidity and precision of their movements whilst thus engaged are wonderful. ‘They first scrape the clay with their mandibles; the small portions gathered are then cleared by the anterior paws and passed to the second pair of feet, which in their turn convey them to the large foliated expansions of the hind shanks, which are adapted normally in bees, as every one knows, for the collection of pollen. The middle feet pat the growing pellets of mortar on the hind legs to keep them in a compact shape as the particles are successively added. The little hods-men soon have: 2 Beene eee as much as they Melipona Bees gathering clay. can carry, and they then fly off. Iwas for some time puzzled to know what the bees did with the clay; but I had afterwards plenty of opportunity for ascertaining. They construct their combs in any suitable crevice in trunks of trees or perpendicular banks, and the clay is required to build up a wall so as to close the gap, with the exception of a small orifice for their own entrance and exit. Most kinds of Melipone are in this way masons as well as workers in wax and pollen-gatherers. One

little species (undescribed), not more than two lines long, builds a neat tubular gallery of clay, kneaded with some viscid substance, outside the entrance to its hive, besides blocking up the crevice in the tree within which it is situated. The mouth of the tube is trumpet-shaped, and at the entrance a number of the pigmy bees are always stationed, apparently acting as sentinels.

It is remarkable that none of the American bees have attained that high degree of architectural skill in the construction of their comb which is shown by the European hive bee. The wax cells of the Melipone are generally oblong, showing only an approximation to the hexagonal shape in places where several of them are built in contact. It would appear that the Old World has produced in bees, as well as in other families of animals, far more advanced forms than the tropics of the New World. A hive of the Melipona fasciculata, which I saw opened, contained about two quarts of pleasantly-tasted liquid honey. The bees, as already remarked, have no sting, but they bite furiously when their colonies are disturbed. The Indian who plundered the hive was completely covered by them; they took a particular fancy to the hair of his head, and fastened on it by hundreds. I found forty-five species of these bees in different parts of the country; the largest was half an inch in length; the smallest were extremely minute, some kinds being not more than one-twelfth of an inch in size. These tiny fellows are often very troublesome in the woods, on account of their familiarity; they settle on one’s face and hands, and, in crawling about, get into the eyes and mouth, or up the nostrils.

The broad expansion of the hind shanks of bees is applied in some species to other uses besides the conveyance of clay and pollen. The female of the handsome golden and black Euglossa Surinamensis has this palette of very large size. This species builds its solitary nest also in crevices of walls or trees; but it closes up the chink with fragments of dried leaves and sticks, cemented together, instead of clay. It visits the cajti trees, and gathers with its hind legs a small quantity of the gum which exudes from their trunks. To this it adds the other materials required from the neighbouring bushes, and when laden flies off to its nest.

Whilst on the subject of bees, I may mention that the neighbourhoods of Santarem and Villa Nova yielded me about one hundred and forty species. The genera are for the most part different from those inhabiting Europe. A very large number make their cells in hollow twigs and branches. As in our own country, the industrious nest-building kinds are attended by other species which do not work or store up food for their progeny, but deposit their ova in the cells of their comrades. Some of these, it is well known, counterfeit the dress and general figure of their victims. ‘To all appearance this similarity of shape and colours between the parasite and its victim is given for the purpose of deceiving the poor hard-working bee, which would otherwise revenge itself by slaying its plunderers. Some parasitic bees, however, have no resemblance to the species they impose upon; probably they

live together on more friendly terms, or have some other means of disarming suspicion. Many Dipterous insects are also parasitic on bees, and wear the same dress as the species they live upon. That the dress of the victimisers is arranged with especial reference to their prey, I think is proved by what I observed at Santarem. The genera of the parasites here are not the same as in Europe; and when they counterfeit working bees, it is the peculiarly-coloured species of their own country that are imitated, and not those of any other region. The European genus Apathus, which mimics European Humble-bees, is not found in South America; but the common Bombus of Santarem, which is remarkable in being wholly of a sooty-black colour, is attended by a sooty-black parasite of a widely-different genus, the Eurytis fune-reus. Many of the little Meliponz have their counterfeits in small Diptera of the family Syrphidze; and the brilliant green or blue bees of the country (Euglossa) have their imitators in parasitic bees of equally bright colours, belonging to genera unknown out of the countries where the Euglossze are found.* To the south my rambles never extended farther than the banks of the Irura, a stream which rises amongst the hills already spoken of, and running through a broad valley, wooded along the margins of the water-courses, falls into the Tapajos, at the head of the bay of Mapiri. All beyond, as before remarked, is terra incognita to the inhabitants of Santarem. The Brazilian settlers on the banks of the Amazons seem to have no taste for explorations by land, and I could find no person willing to accompany me on an excursion farther towards the. interior. Such a journey would be exceedingly difficuit in this country, even if men could be obtained willing to undertake it. Besides, there are reports of a settlement of fierce runaway negroes on the Serra de Mururaru,, and it was considered unsafe to go far in that direction, except with a large armed party. I visited the banks of the Irurd and the rich woods accompanying it, and two other streams in the same neighbourhood, one called the Panéma, and the other the Urumart, once or twicea week during the whole time of my residence in Santarem, and made large collections of their natural productions. These forest brooks, with their clear cold waters brawling over their sandy or pebbly beds, through wild tropical glens, always had a great charm for me. The beauty of the moist, cool, and luxuriant glades was heightened by the contrast they afforded to the sterile country around them. The bare or scantily wooded hills which surround the valley are parched by the rays of the vertical sun. One of them, the Pico do Irura, forms a nearly perfect cone, rising from a small grassy plain to a height of 500 or 600 feet, and its ascent is excessively fatiguing after the long walk from Santarem over the campos. I tried it one day, but did not reach the summit. A dense growth of coarse grasses clothed the steep sides of the hill, with here and there a stunted tree of kinds found in the plain beneath. In bared places, a red crumbly soil is exposed; and in one part a mass of rock, which appeared to me, from its compact texture and the absence of stratification, to be porphyritic; but I am not