In the forest and on the river the sancudos are always busy. Men sometimes get into the vessel's tops, and there cover themselves with sacks, notwithstanding the heat, rather than remain below exposed to their attacks. Fortunately they can not stand a current of air, and so when under way the vessel is comparatively free from them, but when at anchor these pests are something awful. To get rid of them is next to impossible. Creosote will keep them off, but the remedy is as bad as the disease. Whitewash will drive them away, but when dry its power ceases; and the only thing to do is either to cover all exposed parts of the body with black pigment _a la mode Indienne_, or else to "grin and bear it." Scarcely less troublesome than the sancudos are the mosquitoes, although they have the negative merit of biting only by day. They are minute creatures, not much larger than a pin's head; they prefer the backs of the hands to any other spot for their attacks. But, unlike the sancudo, which, when undisturbed, gorges himself until unable to fly, and becomes an easy prey to your avenging finger, the mosquito never seems to take too much to prevent his easy escape on the slightest appearance of danger, being evidently just as wide-awake when full as when empty. Everywhere in long grass lurks the "moquim," a little red insect so small as to be almost imperceptible, but which fastens on the legs, causing the most intolerable itching. There is a fly which burrows in the skin and deposits an egg, both in human beings and animals. This produces a maggot, similar in shape to that of the common blow-fly, but much larger, probably analogous to the Guinea-worm. Then there are "chigos," which burrow mostly in the soles of the feet. You feel an intense itching, and on examination find a little thing like a pea just under the epidermis; this is the bag containing the young chigos, which must be carefully picked out with the point of a knife, and the cavity left filled with tobacco ash. Huge spiders abound, whose very appearance inspires a wholesome dread of a nearer acquaintance, but which are harmless enough if let alone. In fact, on board the steamers, almost every cabin is tenanted by one large spider, whose presence is tolerated on account of his being a deadly foe to cockroaches, which abominable creatures swarm on board. Sometimes he is not visible for a fortnight or more at a time; but he leaves tokens of "having been there," in the shape of the empty husks of cockroaches, from which he has carefully abstracted the interior. These spiders have the power of springing upon their prey from a distance, and some of them are so large and powerful as to kill and devour small birds.