The macavahu, called by the missionaries viuditas, or 'widows in mourning', has soft glossy black hair. Its face is a kind of whitish-blue square mask, which contains its eyes, nose and mouth. Its ears have an edge; are small, pretty and hairless. Its neck has a white area in two rings. Its feet, or hind legs, are black like its body, but its forehands are white outside and black inside. These white spots led the missionaries to recognize a veil, a neck scarf and the gloves of a widow in mourning. The character of this little monkey, which sits up on its hind legs to eat, is not related to its appearance. It has a wild and shy air, and often refuses food even when ravenous. We have seen it remain motionless for hours without sleeping, attentive to everything happening around it. The viudita, when alone, becomes furious at the sight of a bird, and climbs and runs with astonishing speed, and, like a eat, leaps on to its prey and eats all it can. The viuditas accompanied us throughout our entire voyage on the Casiquiare and Río Negro. It is an advantage to study animals for several months in the open air, and not indoors where they lose their natural vivacity.

As soon as you enter the basin of the Atabapo river everything changes: the air, the color of the water, the shape of the river-side trees. By day you no longer suffer the torment of mosquitoes; and their long-legged cousins the zancudos become rare at night. Beyond the San Fernando mission these nocturnal insects disappear altogether. The Orinoco waters are turbid, full of earthy matter, and in the coves give off a faint musky smell from the amount of dead crocodiles and other putrefying animals. To drink that water we had to filter it through a linen cloth. The waters of the Atabapo, on the other hand, are pure, taste good, are without smell, and appear brownish in reflected light and yellow under the sun.

The same reasons that slowed our communications also delayed the publication of our work, which has to be accompanied by a number of engravings and maps. If such difficulties are met when governments are paying, how much worse they are when paid by private individuals. It would have been impossible to overcome these difficulties if the enthusiasm of the editors had not been matched by public reaction. More than two thirds of our work has now been published. The maps of the Orinoco, the Casiquiare and the Magdalena rivers, based on my astronomical observations, together with several hundred plants, have been engraved and are ready to appear. I shall not leave Europe on my Asian journey before I have finished publishing my travels to the New World.