The traveler on the Amazon frequently meets with conical hillocks of compact earth, from three to five feet high, from which radiate narrow covered galleries or arcades. The architects of these wonderful structures are the termites, or "white ants," so called, though they belong to a higher order of insects, widely differing from the true ants. The only thing in common is the principle of division of labor. The termite neuters are subdivided into two classes, soldiers and workers, both wingless and blind. Their great enemy is the ant-eater; but it is a singular fact, noticed by Bates, that the soldiers only attach themselves to the long worm-like tongue of this animal, so that the workers, on whom the prosperity of the termitarum depends, are saved by the self-sacrifice of the fighting caste. The office of the termites in the tropics seems to be to hasten the decomposition of decaying vegetation. But they also work their way into houses, trunks, wardrobes, and libraries. "It is principally owing to their destructiveness" (wrote Humboldt) "that it is so rare to find papers in tropical America older than fifty or sixty years."

Dragon-flies are conspicuous specimens of insect life on the Amazon. The largest and most brilliant kinds are found by the shady brooks and creeks in the recesses of the forest, some of them with green or crimson bodies seven inches long, and their elegant lace-like wings tipped with white or yellow. Still more noticeable are the butterflies. There is a vast number of genera and species, and great beauty of dress, unequaled in the temperate zone. Some idea of the diversity is conveyed by the fact mentioned by Mr. Bates that about 700 species are found within an hour's walk of Pará, and 550 at Ega; while the total number found in the British Islands does not exceed 66, and the whole of Europe supports only 300. After a shower in the dry season the butterflies appear in fluttering clouds (for they live in societies), white, yellow, red, green, purple, black, and blue, many of them bordered with metallic lines and spots of a silvery or golden lustre. The sulphur-yellow and orange-colored kinds predominate. A colossal morpho, seven and a half inches in expanse, and visible a quarter of a mile off, frequents the shady glades; splendid swallow-tailed papilios, green, rose, or velvety-black, are seen only in the thickets; while the Hetaira esmeralda, with transparent wings, having one spot of a violet hue, as it flies over the dead leaves in the dense forest looks "like a wandering petal of a flower." Very abundant is the Heliconius, which plays such an important figure, by its variations, in Wallace's theory of the origin of species. On the Marañon we found Callidryas eubule, a yellow butterfly common in Florida. The most brilliant butterflies are found on the Middle Amazon, out of reach of the strong trade winds. The males far outnumber the other sex, are more richly colored, and generally lead a sunshiny life.

The females are of dull hues, and spend their lives in the gloomy shadows of the forest. Caterpillars and nocturnal moths are rare.

There are no true hive-bees (Apides) in South America,[174] but instead there are about one hundred and fifty species of bees (mostly social Moliponas), smaller than the European, stingless, and constructing oblong cells. Their colonies are much larger than those of the honey-bee. The Trigona occurs on the Napo. Unlike the Melipona, it is not confined to the New World. A large sooty-black Bombus represents our humble-bee. Shrill cicadas, blood-thirsty mantucas, piums, punkies, and musquitoes are always associated in the traveler's memory with the glorious river. Of the last there are several kinds. "The forest musquito belongs to a different species from that of the town, being much larger and having transparent wings. It is a little cloud that one carries about his person every step on a woodland ramble, and their hum is so loud that it prevents one hearing well the notes of birds. The town musquito has opaque, speckled wings, a less severe sting, and a silent way of going to work. The inhabitants ought to be thankful the big noisy fellows never come out of the forest" (Bates, ii., 386). There are few musquitoes below Ega; above that point a musquito net is indispensable. Beetles abound, particularly in shady places, and are of all sizes, from that of a pin's head to several inches in length. The most noticeable are the gigantic Megalosoma and Enema, armed with horns. Very few are carnivorous. "This is the more remarkable," observes Darwin, "when compared to the case of carnivorous quadrupeds, which are so abundant in hot countries." Very few are terrestrial, even the carnivorous species being found clinging to branches and leaves. In going from the pole to the equator we find that insect life increases in the same proportion as vegetable life. There is not a single beetle on Melville Island; eleven species are found in Greenland; in England, 2500; in Brazil, 8000. Here lives the king of spiders, the Mygale Blondii, a monstrous hairy fellow, five inches long, of a brown color, with yellowish lines along its stout legs. Its abode is a slanting subterranean gallery about two feet in length, the sides of which are beautifully lined with silk. Other spiders barricade the walks in the forest with invisible threads; some build nests in the trees and attack birds; others again spin a closely-woven web, resembling fine muslin, under the thatched roofs of the houses.

Of land vertebrates, lizards are the first to attract the attention of the traveler on the equator. Great in number and variety, they are met every where—crawling up the walls of buildings, scampering over the hot, dusty roads, gliding through the forest. They stand up on their legs, carry their tails cocked up in the air, and run with the activity of a warm-blooded animal. It is almost impossible to catch them. Some of them are far from being the unpleasant-looking animals many people imagine; but in their coats of many colors, green, gray, brown, and yellow, they may be pronounced beautiful. Others, however, have a repulsive aspect, and are a yard in length. The iguana, peculiar to the New World tropics, is covered with minute green scales handed with brown (though it changes its color like the chameleon), and has a serrated back and gular pouch. It grows to the length of five feet, and is arboreal. Its white flesh, and its oblong, oily eggs, arc considered great delicacies. We heard of a lady who kept one as a pet. Frogs and toads, the chief musicians in the Amazonian forest, are of all sizes, from an inch to a foot in diameter. The Bufo gigas is of a dull gray color, and is covered with warts. Tree-frogs (Hyla) are very abundant; they do not occur on the Andes or on the Pacific coast. Their quack-quack, drum-drum, hoo-hoo, is one of our pleasant memories of South America. Of snakes there is no lack; and yet they are not so numerous as imagination would make them. There are one hundred and fifty species in South America, or one half as many, on the same area, as in the East Indies. The diabolical family is led by the boa, while the rear is brought up by the Amphisbænas, or "double-headed snakes," which progress equally well with either end forward, so that it is difficult to make head or tail of them. The majority are harmless. The deadly corál is found on both sides of the Andes, and wherever there is a cacao plantation. One of the most beautiful specimens of the venomous kind is a new species (Elaps imperator, Cope), which we discovered on the Marañon. It has a slender body more than two feet in length, with black and red bands margined with yellow, and a black and yellow head, with permanently erect fangs.

[Iguana.]

We have already mentioned the most common birds. Probably, says Wallace, no country in the world contains a greater variety of birds than the Amazonian Valley. But the number does not equal the expectations of the traveler; he may ramble a whole day without meeting one. The rarity, however, is more apparent than real; we forget, for the moment, the vastness of their dwelling-place. The birds of the country, moreover, are gregarious, so that a locality may be deserted and silent at one time and swarming with them at another. Parrots and toucans are the most characteristic groups. To the former belong true parrots, parroquets, and macaws. The first are rarely seen walking, but are rapid flyers and expert climbers. On the trees they are social as monkeys, but in flight they always go in pairs. The parroquets go in flocks. The Hyacinthine macaw (the Araruna of the natives) is one of the finest and rarest species of the parrot family. It is found only on the south side of the Amazon. The macaw was considered sacred by the Maya Indians of Yucatan, and dedicated to the sun. The Quichuans call it guacamayo, guaca meaning sacred. Of toucans there are many species; the largest is the toco, with a beak shaped like a banana; the most beautiful are the curb-crested, or Beauharnais toucans, and the P. flavirostris, whose breast is adorned with broad belts of red, crimson, and black. "Wherefore such a beak?" every naturalist has asked; but the toucan still wags his head, as much as to say, "you can not tell." There must be some other reason than adaptation. Birds of the same habits are found beside it—the ibis, pigeon, spoonbill, and toucan are seen feeding together. "How astonishing are the freaks and fancies of Nature! (wrote the funny Sidney Smith). To what purpose, we say, is a bird placed in the woods of Cayenne with a bill a yard long, making a noise like a puppy-dog, and laying eggs in hollow trees? The toucan, to be sure, might retort, to what purpose are certain foolish, prating members of Parliament created, pestering the House of Commons with their ignorance and folly, and impeding the business of the country? There is no end to such questions; so we will not enter into the metaphysics of the toucan."