The Naturalist on the River Amazons/Volume 2/Chapter 5
ANIMALS OF THE NEIGHBOURHOOD OF EGA.
As may have been gathered from the remarks already made, the neighbourhood of Ega was a fine field for a Natural History collector. With the exception of what could be learnt from the few specimens brought home, after transient visits, by Spix and Martius and the Count de Castelnau, whose acquisitions have been deposited in the public museums of Munich and Paris, very little was known in Europe of the animal tenants of this region; the collections that I had the opportunity of making and sending home attracted, therefore, considerable attention. Indeed, the name of my favourite village has become quite a household word amongst a numerous class of Naturalists, not only in England but abroad, in consequence of the very large number of new species (upwards of 3000) which they have had to describe, with the locality "Ega" attached to them. The discovery of new species, however, forms but a small item in the interest belonging to the study of the living creation. The structure, habits, instincts, and geographical distribution of some of the oldest-known forms supply inexhaustible materials for reflection. The few remarks I have to make on the animals of Ega will relate to the mammals, birds, and insects, and will sometimes apply to the productions of the whole Upper Amazons region. We will begin with the monkeys, the most interesting, next to man, of all animals.
Scarlet-faced Monkeys.—Early one sunny morning, in the year 1855, I saw in the streets of Ega, a number of Indians carrying on their shoulders down to the port, to be embarked on the Upper Amazons steamer, a large cage made of strong lianas, some twelve feet in length and five in height, containing a dozen monkeys of the most grotesque appearance. Their bodies (about eighteen inches in height, exclusive of limbs) were clothed from neck to tail with very long, straight, and shining whitish hair; their heads were nearly bald, owing to the very short crop of thin gray hairs, and their faces glowed with the most vivid scarlet hue. As a finish to their striking physiognomy, they had bushy whiskers of a sandy colour, meeting under the chin, and reddish-yellow eyes. They sat gravely and silently in a group, and altogether presented a strange spectacle. These red-faced apes belonged to a species called by the Indians Uakarí, which is peculiar to the Ega district, and the cage with its contents was being sent as a present by Senhor Chrysostomo, the Director of Indians of the Japurá, to one of the Government officials at Rio Janeiro, in acknowledgment of having
Vol II., page 306.
been made colonel of the new national guard. They had been obtained with great difficulty in the forests which cover the low lands, near the principal mouth of the Japurá, about thirty miles from Ega. It was the first time I had seen this most curious of all the South American monkeys, and one that appears to have escaped the notice of Spix and Martius. I afterwards made a journey to the district inhabited by it, but did not then succeed in obtaining specimens; before leaving the country, however, I acquired two individuals, one of which lived in my house for several weeks.
The scarlet-faced monkey belongs, in all essential points of structure, to the same family (Cebidæ) as the rest of the large-sized American species; but it differs from all its relatives in having only the rudiment of a tail, a member which reaches in some allied kinds the highest grade of development known in the order. It was so unusual to see a nearly tailless monkey from America, that naturalists thought, when the first specimens arrived in Europe, that the member had been shortened artificially. Nevertheless, the Uakarí is not quite isolated from its related species of the same family, several other kinds, also found on the Amazons, forming a graduated passage between the extreme forms as regards the tail. The appendage reaches its perfection in those genera (the Howlers, the Lagothrix and the Spider monkeys) in which it presents on its under-surface near the tip a naked palm, which makes it sensitive and useful as a fifth hand in climbing. In the rest of the genera of Cebidæ (seven in number, containing thirty-eight species), the tail is weaker in structure, entirely covered with hair, and of little or no service in climbing, a few species nearly related to our Uakarí having it much shorter than usual. All the Cebidæ, both long-tailed and short-tailed, are equally dwellers in trees. The scarlet-faced monkey lives in forests, which are inundated during great part of the year, and is never known to descend to the ground; the shortness of its tail is therefore no sign of terrestrial habits, as it is in the Macaques and Baboons of the Old World. It differs a little from the typical Cebidæ in its teeth, the incisors being oblique and, in the upper jaw, converging, so as to leave a gap between the outermost and the canine teeth. Like all the rest of its family, it differs from the monkeys of the old world, and from man, in having an additional grinding-tooth (premolar) in each side of both jaws, making the complete set thirty-six instead of thirty-two in number.
The white Uakarí (Brachyurus calvus), seems to be found in no other part of America than the district just mentioned, namely, the banks of the Japurá, near its principal mouth; and even there it is confined, as far as I could learn, to the western side of the river. It lives in small troops amongst the crowns of the lofty trees, living on fruits of various kinds. Hunters say it is pretty nimble in its motions, but is not much given to leaping, preferring to run up and down the larger boughs in travelling from tree to tree. The mother, as in other species of the monkey order, carries her young on her back. Individuals are obtained alive by shooting them with the blow-pipe and arrows tipped with diluted Urarí poison. They run a considerable distance after being pierced, and it requires an experienced hunter to track them. He is considered the most expert who can keep pace with a wounded one, and catch it in his arms when it falls exhausted. A pinch of salt, the antidote to the poison, is then put in its mouth, and the creature revives. The species is rare, even in the limited district which it inhabits. Senhor Chrysostomo sent six of his most skilful Indians, who were absent three weeks before they obtained the twelve specimens which formed his unique and princely gift. When an independent hunter obtains one, a very high price (thirty to forty milreis[1]) is asked, these monkeys being in great demand for presents to persons of influence down the river.
Adult Uakarís, caught in the way just described, very rarely become tame. They are peevish and sulky, resisting all attempts to coax them, and biting anyone who ventures within reach. They have no particular cry, even when in their native woods; in captivity they are quite silent. In the course of a few days or weeks, if not very carefully attended to, they fall into a listless condition, refuse food and die. Many of them succumb to a disease which I supposed from the symptoms to be inflammation of the chest or lungs. The one which I kept as a pet died of this disorder after I had had it about three weeks. It lost its appetite in a very few days, although kept in an airy verandah; its coat, which was originally long, smooth, and glossy, became dingy and ragged like that of the specimens seen in museums, and the bright scarlet colour of its face changed to a duller hue. This colour, in health, is spread over the features up to the roots of the hair on the forehead and temples, and down to the neck, including the flabby cheeks which hang down below the jaws. The animal, in this condition, looks at a short distance as though some one had laid a thick coat of red paint on its countenance. The death of my pet was slow; during the last twenty-four hours it lay prostrate, breathing quickly, its chest strongly heaving; the colour of its face became gradually paler, but was still red when it expired. As the hue did not quite disappear until two or three hours after the animal was quite dead, I judged that it was not exclusively due to the blood, but partly to a pigment beneath the skin which would probably retain its colour a short time after the circulation had ceased.
After seeing much of the morose disposition of the Uakarí, I was not a little surprised one day at a friend's house to find an extremely lively and familiar individual of this species. It ran from an inner chamber straight towards me after I had sat down on a chair, climbed my legs and nestled in my lap, turning round and looking up with the usual monkey's grin, after it had made itself comfortable. It was a young animal which had been taken when its mother was shot with a poisoned arrow; its teeth were incomplete, and the face was pale and mottled, the glowing scarlet hue not supervening in these animals before mature age; it had also a few long black hairs on the eyebrows and lips. The frisky little fellow had been reared in the house amongst the children, and allowed to run about freely, and take its meals with the rest of the household. There are few animals which the Brazilians of these villages have not succeeded in taming. I have even seen young jaguars running loose about a house, and treated as pets. The animals that I had, rarely became familiar, however long they might remain in my possession, a circumstance due no doubt to their being kept always tied up.
The Uakarí is one of the many species of animals which are classified by the Brazilians as "mortál," or of delicate constitution, in contradistinction to those which are "duro," or hardy. A large proportion of the specimens sent from Ega die before arriving at Pará, and scarcely one in a dozen succeeds in reaching Rio Janeiro alive. It appears, nevertheless, that an individual has once been brought in a living state to England, for Dr. Gray relates that one was exhibited in the gardens of the Zoological Society in 1849. The difficulty it has of accommodating itself to changed conditions probably has some connection with the very limited range or confined sphere of life of the species in its natural state, its native home being an area of swampy woods, not more than about sixty square miles in extent, although no permanent barrier exists to check its dispersal, except towards the south, over a much wider space. When I descended the river in 1859, we had with us a tame adult Uakarí, which was allowed to ramble about the vessel, a large schooner. When we reached the mouth of the Rio Negro, we had to wait four days whilst the custom-house officials at Barra, ten miles distant, made out the passports for our crew, and during this time the schooner lay close to the shore, with its bowsprit secured to the trees on the bank. Well, one morning, scarlet-face was missing, having made his escape into the forest. Two men were sent in search of him, but returned after several hours' absence without having caught sight of the runaway. We gave up the monkey for lost, until the following day, when he re-appeared on the skirts of the forest, and marched quietly down the bowsprit to his usual place on deck. He had evidently found the forests of the Rio Negro very different from those of the delta lands of the Japurá, and preferred captivity to freedom in a place that was so uncongenial to him.
A most curious fact connected with this monkey is the existence of an allied form, or brother species, in a tract of country lying to the west of its district. This differs in being clothed with red instead of white hair, and has been described by Isidore Geoffroy St. Hilaire (from specimens brought to Paris in 1847 by the Comte de Castlenau) as a distinct species, under the name of Brachyurus rubicundus. It wholly replaces the white form in the western parts of the Japurá delta: that is to say, in a uniform district of country, 150 miles in length, and sixty to eighty in breadth, the eastern half is tenanted exclusively by white Uakarís, and the western half by red ones. The district, it may be mentioned, is crossed by several channels, which at the present time doubtless serve as barriers to the dispersal of monkeys, but cannot have done so for many centuries, as the position of low alluvial lands, and the direction of channels in the Amazons Valley, change considerably in the course of a few years. The red-haired Uakarí appears to be most frequently found in the forests lying opposite to the mouth of the river which leads to Fonteboa, and ranges thence to the banks of the Uatí-paraná, the most westerly channel of the Japurá, situated near Tunantins. Beyond that point to the west there is no trace of either the red or the white form, nor of any other allied species. Neither do they pass to the eastward of the main mouth of the Japurá, or to the south shore of the Solimoens. How far they range northwards along the banks of the Japurá, I could not precisely ascertain; Senhor Chrysostomo, however, assured me that at 180 miles from the mouth of this river, neither white nor red Uakarí is found, but that a third, black-faced and gray-haired species, takes their place. I saw two adult individuals of Brachyurus rubicundus at Ega, and a young one at Fonteboa; but was unable to obtain specimens myself, as the forests were inundated at the time I visited their locality. I was surprised to find the hair of the young animal much paler in colour than that of the adults, it being of a sandy and not of a brownish-red hue, and consequently did not differ very much from that of the white species; the two forms, therefore, are less distinct from each other in their young than in their adult states. The fact of the range of these singular monkeys being so curiously limited as here described, cannot be said to be established until the country lying between the northern shore of the Solimoens and New Granada be well explored, but there can be no doubt of the separation of the two forms in the Delta lands of the Japurá, and this is a most instructive fact in the geographical distribution of animals.
The Parauacú Monkey.—Another Ega monkey, nearly related to the Uakarís, is the Parauacú (Pithecia hirsuta), a timid inoffensive creature, with a long bear-like coat of harsh speckled-gray hair. The long fur hangs over the head, half concealing the pleasing, diminutive face, and clothes also the tail to the tip, which member is well developed, being eighteen inches in length, or longer than the body. The Parauacú is found on the "terra firma" lands of the north shore of the Solimoens from Tunantins to Peru. It exists also on the south side of the river, namely on the banks of the Teffé, but there under a changed form, which differs from its type in colours about as much as the red differs from the white Uakarí. This form has been described by Dr. Gray as a distinct species, under the name of Pithecia albicans. The Parauacú is also a very delicate animal, rarely living many weeks in captivity; but anyone who succeeds in keeping it alive for a month or two, gains by it a most affectionate pet. One of the specimens of Pithecia albicans now in the British Museum was, when living, the property of a young Frenchman, a neighbour of mine at Ega. It became so tame in the course of a few weeks that it followed him about the streets like a dog. My friend was a tailor, and the little pet used to spend the greater part of the day seated on his shoulder, whilst he was at work on his board. It showed, nevertheless, great dislike to strangers, and was not on good terms with any other member of my friend's household than himself. I saw no monkey that showed so strong a personal attachment as this gentle, timid, silent little creature. The eager and passionate Cebi seem to take the lead of all the South American monkeys in intelligence and docility, and the Coaitá has perhaps the most gentle and impressible disposition; but the Parauacú, although a dull, cheerless animal, excels all in this quality of capability of attachment to individuals of our own species. It is not wanting, however, in intelligence as well as moral goodness, proof of which was furnished one day by an act of our little pet. My neighbour had quitted his house in the morning without taking Parauacú with him, and the little creature having missed its friend, and concluded, as it seemed, that he would be sure to come to me, both being in the habit of paying me a daily visit together, came straight to my dwelling, taking a short cut over gardens, trees, and thickets, instead of going the roundabout way of the street. It had never done this before, and we knew the route it had taken only from a neighbour having watched its movements. On arriving at my house and not finding its master, it climbed to the top of my table, and sat with an air of quiet resignation waiting for him. Shortly afterwards my friend entered, and the gladdened pet then jumped to its usual perch on his shoulder.
Owl-faced Night Apes.—A third interesting genus of monkeys, found near Ega, are the Nyctipitheci, or night apes, called Ei-á by the Indians. Of these I found two species, closely related to each other but nevertheless quite distinct, as both inhabit the same forests, namely, those of the higher and drier lands, without mingling with each other or intercrossing. They sleep all day long in hollow trees, and come forth to prey on insects and eat fruits only in the night. They are of small size, the body being about a foot long, and the tail fourteen inches, and are thickly clothed with soft grey and brown fur, similar in substance to that of the rabbit. Their physiognomy reminds one of an owl, or tiger-cat: the face is round and encircled by a ruff of whitish fur; the muzzle is not at all prominent; the mouth and chin are small; the ears are very short, scarcely appearing above the hair of the head; and the eyes are large and yellowish in colour, imparting the staring expression of nocturnal animals of prey. The forehead is whitish, and decorated with three black stripes, which in one of the species (Nyctipithecus trivirgatus) continue to the crown, and in the other (N. felinus) meet on the top of the forehead. N. trivirgatus was first described by Humboldt, who discovered it on the banks of the Cassiquiare, near the head waters of the Rio Negro.
One cannot help being struck by this curious modification of the American type of monkeys, for the owl-faced night-apes have evidently sprung from the same stock as the rest of the Cebidæ, as they do not differ much in all essential points from the Whaiápu-sais (Callithrix), and the Sai-mirís (Chrysothrix). They have nails of the ordinary form to all their fingers, and semi-opposable thumbs; but the molar teeth (contrary to what is usual in the Cebidæ) are studded with sharp points, showing that their natural food is principally insects.
I kept a pet animal of the N. trivirgatus for many months, a young one having been given to me by an Indian compadre, as a present from my newly-baptised godson. These monkeys, although sleeping by day, are aroused by the least noise; so that, when a person passes by a tree in which a number of them are concealed, he is startled by the sudden apparition of a group of little striped faces crowding a hole in the trunk. It was in this way that my compadre discovered the colony from which the one given to me was taken. I was obliged to keep my pet chained up; it therefore never became thoroughly familiar. I once saw, however, an individual of the other species (N. felinus) which was most amusingly tame. It was as lively and nimble as the Cebi, but not so mischievous and far more confiding in its disposition, delighting to be caressed by all persons who came into the house. But its owner, the Municipal Judge of Ega, Dr. Carlos Mariana, had treated it for many weeks with the greatest kindness, allowing it to sleep with him at night in his hammock, and to nestle in his bosom half the day as he lay reading. It was a great favourite with every one, from the cleanliness of its habits and the prettiness of its features and ways. My own pet was kept in a box, in which was placed a broad-mouthed glass jar; into this it would dive, head foremost, when any one entered the room, turning round inside, and thrusting forth its inquisitive face an instant afterwards to stare at the intruder. It was very active at night, venting at frequent intervals a hoarse cry, like the suppressed barking of a dog, and scampering about the room, to the length of its tether, after cockroaches and spiders. In climbing between the box and the wall, it straddled the space, resting its hands on the palms and tips of the outstretched fingers with the knuckles bent at an acute angle, and thus mounted to the top with the greatest facility. Although seeming to prefer insects, it ate all kinds of fruit, but would not touch raw or cooked meat, and was very seldom thirsty. I was told by persons who had kept these monkeys loose about the house, that they cleared the chambers of bats as well as insect vermin. When approached gently, my Ei-á allowed itself to be caressed; but when handled roughly, it always took alarm, biting severely, striking out its little hands, and making a hissing noise like a cat. As already related, my pet was killed by a jealous Caiarára monkey, which was kept in the house at the same time.
I have mentioned the near relationship of the night apes to the Sai-mirís (Chrysothrix), which are amongst the commonest of the ordinary monkeys of the American forests. This near relationship is the more necessary to be borne in mind, as some zoologists have drawn a comparison between the Nyctipitheci and the Microcebi, Nycticebi, and Loris, nocturnal apes of the Lemur family inhabiting Ceylon and Java, and it might be erroneously inferred that our American Ei-ás were related more closely to these Old World forms than they are to the rest of the New World monkeys. The Nycticebus of Java has also large nocturnal eyes, short ears, and a physiognomy similar to that of our Nyctipitheci; resemblances which might seem to be strong proofs of blood-relationship, but these points are fallacious guides in ascertaining the genealogy of these animals; they are simply resemblances of analogy, and merely show that a few species belonging to utterly dissimilar families have been made similar by being adapted to similar modes of life. The Loris and their relatives of Tropical Asia have six incisor teeth to the lower jaws, and belong, in all other essential points of structure, to the Lemur family, which has not a single representative in the New World. The Ei-ás have teeth of the same number, and growing in nearly the same position, as their near relatives the Sai-mirís. I obtained, moreover, yet stronger proof of this close relationship between the night and day monkeys of America, in finding a species on the Upper Amazons which supplies a link between them. This one had ears nearly as short as those of the night apes, and also a striped forehead; the stripes being, however, two in number, instead of three: the colours of the body were very similar to those of the well-known Chrysothrix sciureus, and the eyes were fitted for day vision.
Barrigudo Monkeys.—Ten other species of monkeys were found, in addition to those already mentioned, in the forests of the Upper Amazons. All were strictly arboreal and diurnal in their habits, and lived in flocks, travelling from tree to tree, the mothers with their children on their backs; leading, in fact, a life similar to that of the Parárauáte Indians, and, like them, occasionally plundering the plantations which lie near their line of march. Some of them were found also on the Lower Amazons, and have been noticed in former chapters of this narrative. Of the remainder, the most remarkable is the Macaco barrigudo, or big-bellied monkey of the Portuguese colonists, a species of Lagothrix. The genus is closely allied to the Coaitás, or spider monkeys, having, like them, exceedingly strong and flexible tails, which are furnished underneath with a naked palm like a hand, for grasping. The Barrigudos, however, are very bulky animals, whilst the spider monkeys are remarkable for the slenderness of their bodies and limbs. I obtained specimens of what have been considered two species, one (L. olivaceus of Spix?) having the head clothed with gray, the other (L. Humboldtii) with black fur. They both live together in the same places, and are probably only differently-coloured individuals of one and the same species. I sent home a very large male of one of these kinds, which measured twenty-seven inches in length of trunk, the tail being twenty-six inches long; it was the largest monkey I saw in America, with the exception of a black Howler, whose body was twenty-eight inches in height. The skin of the face in the Barrigudo is black and wrinkled, the forehead is low, with the eye-brows projecting, and, in short, the features altogether resemble in a striking manner those of an old negro. In the forests, the Barrigudo is not a very active animal; it lives exclusively on fruits, and is much persecuted by the Indians, on account of the excellence of its flesh as food. From information given me by a collector of birds and mammals, whom I employed, and who resided a long time amongst the Tucuna Indians, near Tabatinga, I calculated that one horde of this tribe, 200 in number, destroyed 1200 of these monkeys annually for food. The species is very numerous in the forests of the higher lands, but, owing to long persecution, it is now seldom seen in the neighbourhood of the larger villages. It is not found at all on the Lower Amazons. Its manners in captivity are grave, and its temper mild and confiding, like that of the Coaitás. Owing to these traits, the Barrigudo is much sought after for pets; but it is not hardy like the Coaitás, and seldom survives a passage down the river to Pará.
Marmosets.—It now only remains to notice the Marmosets, which form the second family of American monkeys. Our old friend Midas ursulus, of Pará and the Lower Amazons, is not found on the Upper river, but in its stead a closely-allied species presents itself, which appears to be the Midas rufoniger of Gervais, whose mouth is bordered with longish white hairs. The habits of this species are the same as those of the M. ursulus, indeed it seems probable that it is a form or race of the same stock, modified to suit the altered local conditions under which it lives. One day, whilst walking along a forest pathway, I saw one of these lively little fellows miss his grasp as he was passing from one tree to another along with his troop. He fell head foremost, from a height of at least fifty feet, but managed cleverly to alight on his legs in the pathway; quickly turning round he gave me a good stare for a few moments, and then bounded off gaily to climb another tree. At Tunantins, I shot a pair of a very handsome species of Marmoset, the M. rufiventer, I believe, of zoologists. Its coat was very glossy and smooth; the back deep brown, and the underside of the body of rich black and reddish hues. A third species (found at Tabatinga, 200 miles further west) is of a deep black colour, with the exception of a patch of white hair around its mouth. The little animal, at a short distance, looks as though it held a ball of snow-white cotton in its teeth. The last I shall mention is the Hapale pygmæus, one of the most diminutive forms of the monkey order. I obtained, near St. Paulo, three full-grown specimens, which measured only seven inches in length of body. The pretty Lilliputian face is furnished with long brown whiskers, which are naturally brushed back over the ears. The general colour of the animal is brownish-tawny, but the tail is elegantly barred with black. I was surprised, on my return to England, to learn that the pigmy marmoset was found also in Mexico, no other Amazonian monkey being known to wander far from the great river plain. Thus the smallest, and apparently the feeblest, species of the whole order, is one which has, by some means, become the most widely dispersed.
The Jupurá.—A curious animal, known to naturalists as the Kinkajou, but called Jupurá by the Indians of the Amazons, and considered by them as a kind of monkey, may be mentioned in this place. It is the Cercoleptes caudivolvus of zoologists, and has been considered by some authors as an intermediate form between the Lemur family of apes and the plantigrade Carnivora, or Bear family. It has decidedly no close relationship to either of the groups of American monkeys, having six cutting teeth to each jaw, and long claws intead of nails, with extremities of the usual shape of paws instead of hands. Its muzzle is conical and pointed, like that of many Lemurs of Madagascar; the expression of its countenance, and its habits and actions, are also very similar to those of Lemurs. Its tail is very flexible towards the tip, and is used to twine round branches in climbing. I did not see or hear anything of this animal whilst residing on the Lower Amazons, but on the banks of the Upper river, from the Teffé to Peru, it appeared to be rather common. It is nocturnal in its habits, like the owl-faced monkeys, although, unlike them, it has a bright, dark eye. I once saw it in considerable numbers, when on an excursion with an Indian companion along the low Ygapó shores of the Teffé, about twenty miles above Ega. We slept one night at the house of a native family living in the thick of the forest, where a festival was going on, and there being no room to hang our hammocks under shelter, on account of the number of visitors, we lay down on a mat in the open air, near a shed which stood in the midst of a grove of fruit-trees and pupunha palms. After midnight, when all became still, after the uproar of holiday-making, as I was listening to the dull, fanning sound made by the wings of impish hosts of vampire bats crowding round the Cajú trees, a rustle commenced from the side of the woods, and a troop of slender, long-tailed animals were seen against the clear moonlit sky, taking flying leaps from branch to branch through the grove. Many of them stopped at the pupunha trees, and the hustling, twittering, and screaming, with sounds of falling fruits, showed how they were employed. I thought, at first, they were Nyctipitheci, but they proved to be Jupurás, for the owner of the house early next morning caught a young one, and gave it to me. I kept this as a pet animal for several weeks, feeding it on bananas and mandioca-meal mixed with treacle. It became tame in a very short time, allowing itself to be caressed, but making a distinction in the degree of confidence it showed between myself and strangers. My pet was unfortunately killed by a neighbour's dog, which entered the room where it was kept. The animal is so difficult to obtain alive, its place of retreat in the day-time not being known to the natives, that I was unable to procure a second living specimen.
As I shall not have occasion again to enter on the subject of monkeys, a few general remarks will be here in place, as a summary of my observations on this important order of animals in the Amazons region. The total number of species of monkeys which I found inhabiting the margins of the Upper and Lower Amazons, was thirty-eight. They belonged to twelve different genera, forming two distinct families, the number of genera and families, here as well as in other orders of animals or plants, expressing roughly the amount of diversity existing with regard to forms. All the New World genera of apes, except one (Eriodes, closely allied to the Coaitás, but having claw-shaped nails to the fingers), are represented in the Amazons region. With these ample materials before us, let us draw a comparison between the monkeys of the new continent, and their kindred of the Old World. It seems highly probable that the larger land areas, both continents and islands, on the surface of our globe, became separated pretty nearly as they now are, soon after the first forms of this group of animals came into existence: it will be interesting, therefore, to see how differently the subsequent creations of species have proceeded in each of the separated areas.
The American monkeys are distinguished, as a body, from all those found in the Old World. Upon this point, there is no difference of opinion amongst modern zoologists. It is not probable, therefore, that species of the one continent have passed over to the other, since these great tracts of land received their present inhabitants of this order. The American productions present a cluster of forms, namely, about eighty-six species, separated into thirteen genera, which although greatly diversified amongst themselves, in no case show signs of near relationship to any of the still more diversified forms of the same order belonging to the eastern hemisphere. One of the two American families (Cebidæ) has thirty-six teeth, whilst the corresponding family (Pithecidæ) of Old World apes has, like man, only thirty-two teeth; the difference arising from the Cebidæ having an additional false molar tooth[2] to each side of both jaws. This important character is constant throughout all the varied forms of which the Cebidæ family is composed; being equally present in the prehensile-tailed group, with its four genera containing twenty-seven species, differing in form and clothing, shape of claws, mental characteristics, and condition of thumb of the anterior hands; and in the true Cebi and the group of Sagouins, with six genera and twenty-four species, including day apes and night apes, short furred and long-haired apes, apes with excessively long tails, and apes with rudimentary tails. The second American family, the Marmosets, have thirty-two teeth, like the Old World monkeys and man; but this identity of number arises from one of the true molars being absent; the Marmosets have three premolar teeth, like the Cebidæ, and are therefore quite as far removed as the Cebidæ from all the forms of the Old World. They are, moreover, a low type of apes, having a smooth brain, and claws instead of nails, although they are gentle and playful in disposition, and have a visage which presents an open facial angle.
The Old World apes, as just observed, are far more diversified amongst themselves, than are those of the New World. They form, in the first place, two widely distinct groups or sub-orders, Pithecidæ and Lemurs, and comprise about 125 species, divided into twenty-one genera. The Lemur group contains a remarkably great diversity of forms; this is shown by their being naturally divisible into four families,[3] and twelve genera, although containing only twenty-five species. Their teeth are very irregular in number and position, but never correspond with those of the Pithecidæ or Cebidæ. These four families, in structure, are more widely separated from each other than are the two American groups of the same denomination. The Lemurs also contain a number of anomalous or isolated forms, which, by their teeth, number of teats, and other features, connect the monkeys with other and lower orders of the mammal class; namely, the Rodents, the Insectivora, and the Bats. All the typical Lemurs, which constitute the great majority of the family, inhabit exclusively the Island of Madagascar.
The Pithecidæ are divisible into three groups, which again are much more distinct from each other than the subordinate groups of Cebidæ. These are the Anthropoid section, to which some zoologists consider man himself belongs, comprising the Gorilla, the Chimpanzee, the Orangs and the Gibbons; the Guenons (which, in their forms, tempers, and habits, resemble the Cebidæ), and lastly, the Baboons, whose extreme forms—the dog-faced species, with nose extending to the tip of the muzzle—seem like a degradation of the monkey type. There is nothing at all resembling the Anthropoid apes and the Baboons existing on the American continent. The Guenons, too, have only a superficial resemblance to American monkeys; for they have all thirty-two teeth, nostrils opening in a downward direction (instead of on the sides, like the Cebidæ and Marmosets), and are, moreover, linked to the Baboons through intermediate forms (Macacus), and the possession of callosities on the breech, and other signs of blood-relationship.
A few more words on the peculiar way in which these groups of monkeys are distributed over the earth's surface. We may consider, in connection with this subject, the great land masses of the warmer parts of the earth to be four in number. 1. Australia, with New Guinea and its neighbouring islands: 2. Madagascar: 3. America: 4. The Continental mass of the Old World, comprising Europe, Africa, Asia, and the Islands of the Malay Archipelago, which latter are connected with Asia by a shallow sea, whilst they are separated from New Guinea by a channel of very deep water; the shallow sea pointing to a former, but recent, union of the lands which it connects, the deep channel a complete and enduring severance of the lands which it separates. Now, with regard to monkeys, these four land masses seem to have had these animals allotted to them in the most capricious way possible, if we are to take for granted that the species were arbitrarily created on the lands where they are now found. Australia, with soil and climate as well adapted for Baboons as Africa, where they abound, and New Guinea, with rich humid forests as suitable for Orangs and Gibbons as the very similar island of Borneo, have, neither of them, a single species of native monkey. Madagascar possesses only Lemurs, the most lowly-organised group of apes, although the neighbouring continent of Africa contains numerous species of all families of Old World apes. America, as we have seen, has no Lemurs, and not a single representative of the Old World groups of the order, but is well peopled by genera and species belonging to two distinct groups peculiar to the continent. Lastly, the Old World continental mass, with a few anomalous forms of Lemurs scattered here and there, is the exclusive home of the whole of the Pithecidæ family, which presents a series of forms graduating from the debased Baboon to the Gorilla, which some zoologists consider to approach near to man in his organisation.
What does all this mean? Why are the different forms apportioned in this way to the various lands of the earth? Why is Australia with New Guinea destitute of monkeys, and why should Madagascar have stopped short at Lemurs, whilst America has gone on to prehensile-tailed Cebidæ, and the Old-World continent continued to Gibbons, Orangs, Chimpanzee, and Gorilla? Is it that the greater land masses have seen a larger amount of geological and climatal changes with corresponding changes in the geographical relations of species? Moreover, why should the smaller groups of the order be confined to smaller areas within the greater areas peopled by the families to which they belong? For, it must be added, the true Lemurs are confined to Madagascar, the Gibbons and others to South Eastern Asia, the dog-faced baboons to Africa, and, as we have seen, the scarlet-faced monkeys to a limited area on the Upper Amazons. May we be allowed to explain the absence of these animals from New Guinea with Australia, by the supposition that those lands were separated from South Eastern Asia before the first forms of the order came into existence? If so, it may be concluded that Madagascar became separated from Africa, and America from the continental mass of the old world before the Pithecidæ originated. But, if these explanations, founded on natural causes, be entertained, we commit ourselves, by the fact of entertaining them, to the admission that natural causes are competent to explain the existence or non-existence of forms in a given area, and why may not the exercise of our reason, founded on carefully observed and collated facts, be carried a step farther, namely to the origin of the species of monkeys themselves? I have already shown how singularly species of monkeys vary in different localities, and have given the striking case of the white and red-haired Uakarís. If these two forms, which are considered by the most eminent naturalists as distinct species, have originated, as the facts of their distribution plainly tell us they have, from one and the same stock, why may not the various species of Lemurs, of Baboons, of Gibbons, and so forth, given the necessary amount of time and climatal changes, have originated in the same way? And if we can thus account for the origin of the species of one genus, on what grounds can we deny that the genera of the same family, or the families of the same order, have also proceeded from a common stock? I throw out these suggestions simply for the consideration of thoughtful readers, but must add, that unless the common origin, at least, of the species of a family be admitted, the problem of the distribution of monkeys over the earth's surface must remain an inexplicable mystery, whilst, if admitted, a flood of light illuminates the subject, and promises an early solution to honest and patient investigation. These questions, also, show how interesting and difficult are the problems which Natural History, granted the right and ability of the human mind to deal with them, has to solve.
It is a suggestive fact that all the fossil monkeys which have been found in Europe and America, belong in each case to the types which are still peculiar to the continent which they inhabit. The European fossils are all of the Pithecidæ family, the South American all belong to the Cebidæ and Marmoset families. The separation of the two continental masses (at least of their warm zones) must therefore be of great geological antiquity. It is interesting to trace how the diversification of forms (if the expression may be allowed), since the separation, has gone on in Tropical America. What wide divergence as to size, forms, habits, and mental dispositions, between the silver marmoset so small that it may be inclosed in the two hands, and the strong and savage black Howler, nearly two feet and a half in length of trunk! Yet there has been no direct advance in the organisation of the order towards a higher type, such as is exhibited in the old world. America, for her share, has produced the most perfectly arboreal monkey in the world; but beyond the perfection of the arboreal type she does not go. The retention of arboreal forms throughout long geological ages, may teach geologists that there must always have been extensive land areas covered by forests on the site of the tropical zone of America. It is curious to reflect, in conjunction with the fact of the advance of the American Quadrumana having halted at a low stage, that ethnologists have almost unanimously come to the conclusion that the race of men now inhabiting the American continent are not Autochthones of America, the land of the Cebidæ, but immigrants from the Old World continent, the land of the Anthropoid group of the order Quadrumana.
Bats.—The only other mammals that I shall mention are the bats, which exist in very considerable numbers and variety in the forest, as well as in the buildings of the villages. Many small and curious species living in the woods, conceal themselves by day under the broad leaf-blades of Heliconiæ and other plants which grow in shady places; others cling to the trunks of trees. Whilst walking through the forest in the daytime, especially along gloomy ravines, one is almost sure to startle bats from their sleeping-places; and at night they are often seen in great numbers flitting about the trees on the shady margins of narrow channels. I captured altogether, without giving especial attention to bats, sixteen different species at Ega.
The Vampire Bat.—The little gray bloodsucking Phyllostoma, mentioned in a former chapter as found in my chamber at Caripí, was not uncommon at Ega, where everyone believes it to visit sleepers and bleed them in the night. But the vampire was here by far the most abundant of the family of leaf-nosed bats. It is the largest of all the South American species, measuring twenty-eight inches in expanse of wing. Nothing, in animal physiognomy can be more hideous than the countenance of this creature when viewed from the front; the large, leathery ears standing out from the sides and top of the head, the erect spear-shaped appendage on the tip of the nose, the grin and the glistening black eye all combining to make up a figure that reminds one of some mocking imp of fable. No wonder that imaginative people have inferred diabolical instincts on the part of so ugly an animal. The vampire, however, is the most harmless of all bats, and its inoffensive character is well known to residents on the banks of the Amazons. I found two distinct species of it, one having the fur of a blackish colour, the other of a ruddy hue, and ascertained that both feed chiefly on fruits. The church at Ega was the head-quarters of both kinds; I used to see them, as I sat at my door during the short evening twilights, trooping forth by scores from a large open window at the back of the altar, twittering cheerfully as they sped off to the borders of the forest. They sometimes enter houses; the first time I saw one in my chamber, wheeling heavily round and round, I mistook it for a pigeon, thinking that a tame one had escaped from the premises of one of my neighbours. I opened the stomachs of several of these bats, and found them to contain a mass of pulp and seeds of fruits, mingled with a few remains of insects.[4] The natives say they devour ripe cajús and guavas on trees in the gardens, but on comparing the seeds taken from their stomachs with those of all cultivated trees at Ega, I found they were unlike any of them; it is therefore probable that they generally resort to the forest to feed, coming to the village in the morning to sleep, because they find it more secure from animals of prey than their natural abodes in the woods.
Birds.—I have already had occasion to mention several of the more interesting birds found in the Ega district. The first thing that would strike a new-comer in the forests of the Upper Amazons would be the general scarcity of birds; indeed, it often happened that I did not meet with a single bird during a whole day's ramble in the richest and most varied parts of the woods. Yet the country is tenanted by many hundred species, many of which are, in reality, abundant, and some of them conspicuous from their brilliant plumage. The cause of their apparent rarity is to be sought in the sameness and density of the thousand miles of forest which constitute their dwelling-place. The birds of the country are gregarious, at least during the season when they are most readily found; but the frugivorous kinds are to be met with only when certain wild fruits are ripe, and to know the exact localities of the trees requires months of experience. It would not be supposed that the insectivorous birds are also gregarious; but they are so, numbers of distinct species, belonging to many different families, joining together in the chase or search of food. The proceedings of these associated bands of insect-hunters are not a little curious, and merit a few remarks.
Whilst hunting along the narrow pathways that are made through the forest in the neighbourhood of houses and villages, one may pass several days without seeing many birds; but now and then the surrounding bushes and trees appear suddenly to swarm with them. There are scores, probably hundreds of birds, all moving about with the greatest activity—woodpeckers and Dendrocolaptidæ (from species no larger than a sparrow to others the size of a crow) running up the tree trunks; tanagers,[5] ant-thrushes, humming-birds, fly-catchers, and barbets flitting about the leaves and lower branches. The bustling crowd loses no time, and although moving in concert, each bird is occupied, on its own account, in searching bark or leaf or twig; the barbets visiting every clayey nest of termites on the trees which lie in the line of march. In a few minutes the host is gone, and the forest path remains deserted and silent as before. I became, in course of time, so accustomed to this habit of birds in the woods near Ega, that I could generally find the flock of associated marauders whenever I wanted it. There appeared to be only one of these flocks in each small district; and, as it traversed chiefly a limited tract of woods of second growth, I used to try different paths until I came up with it.
The Indians have noticed these miscellaneous hunting parties of birds, but appear not to have observed that they are occupied in searching for insects. They have supplied their want of knowledge, in the usual way of half-civilised people, by a theory which has degenerated into a myth, to the effect that the onward moving bands are led by a little grey bird, called the Papá-uirá, which fascinates all the rest, and leads them a weary dance through the thickets. There is certainly some appearance of truth in this explanation; for sometimes stray birds, encountered in the line of march, are seen to be drawn into the throng, and purely frugivorous birds are now and then found mixed up with the rest, as though led away by some will-o'-the-wisp. The native women, even the white and half-caste inhabitants of the towns, attach a superstitious value to the skin and feathers of the Papá-uirá, believing that if they keep them in their clothes' chest, the relics will have the effect of attracting for the happy possessors a train of lovers and followers. These birds are consequently in great demand in some places, the hunters selling them at a high price to the foolish girls, who preserve the bodies by drying flesh and feathers together in the sun. I could never get a sight of this famous little bird in the forest. I once employed Indians to obtain specimens for me; but, after the same man (who was a noted woodsman) brought me, at different times, three distinct species of birds as the Papá-uirá, I gave up the story as a piece of humbug. The simplest explanation appears to be this; that the birds associate in flocks from the instinct of self-preservation, and in order to be a less easy prey to hawks, snakes, and other enemies than they would be if feeding alone.
Toucans.—Cuvier's Toucan.—Of this family of birds, so conspicuous from the great size and light structure of their beaks, and so characteristic of Tropical American forests, five species[6] inhabit the woods of Ega. The largest of all the Toucans found on the Amazons, namely, the Ramphastos toco, called by the natives Tocáno pacova, from its beak resembling in size and shape a banana or pacova, appears not to reach so far up the river as Ega. It is abundant near Pará, and is found also on the low islands of the Rio Negro, near Barra, but does not seem to range much farther to the west. The commonest species at Ega is Cuvier's Toucan, a large bird, distinguished from its nearest relatives by the feathers at the bottom of the back being of a saffron hue instead of red. It is found more or less numerously throughout the year, as it breeds in the neighbourhood, laying its eggs in holes of trees, at a great height from the ground. During most months of the year, it is met with in single individuals or small flocks, and the birds are then very wary. Sometimes one of these little bands of four or five is seen perched, for hours together, amongst the topmost branches of high trees, giving vent to their remarkably loud, shrill, yelping cries, one bird, mounted higher than the rest, acting, apparently, as leader of the inharmonious chorus; but two of them are often heard yelping alternately, and in different notes. These cries have a vague resemblance to the syllables Tocáno, Tocáno, and hence the Indian name of this genus of birds. At these times it is difficult to get a shot at Toucans, for their senses are so sharpened that they descry the hunter before he gets near the tree on which they are perched, although he may be half-concealed amongst the underwood, 150 feet below them. They stretch their necks downwards to look beneath, and on espying the least movement amongst the foliage, fly off to the more inaccessible parts of the forest. Solitary Toucans are sometimes met with at the same season, hopping silently up and down the larger boughs, and peering into crevices of the tree-trunks. They moult in the months from March to June, some individuals earlier, others later. This season of enforced quiet being passed, they make their appearance suddenly in the dry forest, near Ega, in large flocks, probably, assemblages of birds gathered together from the neighbouring Ygapó forests, which are then flooded and cold. The birds have now become exceedingly tame, and the troops travel with heavy laborious flight from bough to bough amongst the lower trees. They thus become an easy prey to hunters, and every one at Ega, who can get a gun of any sort and a few charges of powder and shot, or a blow-pipe, goes daily to the woods to kill a few brace for dinner; for, as already observed, the people of Ega live almost exclusively on stewed and roasted Toucans during the months of June and July. The birds are then very fat, and the meat exceedingly sweet and tender. I did not meet with Cuvier's Toucan on the Lower Amazons; in that region, the sulphur and white-breasted Toucan (Ramphastos Vitellinus) seems to take its place, this latter species, on the other hand, being quite unknown on the Upper Amazons. It is probable they are local modifications of one and the same stock.
No one, on seeing a Toucan, can help asking what is the use of the enormous bill, which, in some species, attains a length of seven inches, and a width of more than two inches. A few remarks on this subject may be here introduced. The early naturalists, having seen only the bill of a Toucan, which was esteemed as a marvellous production by the virtuosi of the sixteenth and seventeenth centuries, concluded that the bird must have belonged to the aquatic and web-footed order, as this contains so many species of remarkable development of beak, adapted for seizing fish. Some travellers also related fabulous stories of Toucans resorting to the banks of rivers to feed on fish, and these accounts also encouraged the erroneous views of the habits of the birds, which, for a long time, prevailed. Toucans, however, are now well known to be eminently arboreal birds, and to belong to a group (including trogons, parrots, and barbets[7]), all of whose members are fruit-eaters. On the Amazons, where these birds are very common, no one pretends ever to have seen a Toucan walking on the ground in its natural state, much less acting the part of a swimming or wading bird. Professor Owen found, on dissection, that the gizzard in Toucans is not so well adapted for the trituration of food as it is in other vegetable feeders, and concluded, therefore, as Broderip had observed the habit of chewing the cud in a tame bird, that the great toothed bill was useful in holding and re-masticating the food. The bill can scarcely be said to be a very good contrivance for seizing and crushing small birds, or taking them from their nests in crevices of trees, habits which have been imputed to Toucans by some writers. The hollow, cellular structure of the interior of the bill, its curved and clumsy shape, and the deficiency of force and precision when it is used to seize objects, suggest a want of fitness, if this be the function of the member. But fruit is undoubtedly the chief food of Toucans, and it is in reference to their mode of obtaining it that the use of their uncouth bills is to be sought.
Flowers and fruits on the crowns of the large trees of South American forests grow, principally, towards the end of slender twigs, which will not bear any considerable weight; all animals, therefore, which feed upon fruit, or on insects contained in flowers, must, of course, have some means of reaching the ends of the stalks from a distance. Monkeys obtain their food by stretching forth their long arms and, in some instances, their tails, to bring the fruit near to their mouths. Humming-birds are endowed with highly-perfected organs of flight, with corresponding muscular development, by which they are enabled to sustain themselves on the wing before blossoms whilst rifling them of their contents. These strong-flying creatures, however, will, whenever they get a chance, remain on their perches whilst probing neighbouring flowers for insects. Trogons have feeble wings, and a dull, inactive temperament. Then mode of obtaining food is to station themselves quietly on low branches in the gloomy shades of the forest, and eye the fruits on the surrounding trees, darting off, as if with an effort, every time they wish to seize a mouthful, and returning to the same perch. Barbets (Capitoninæ) seem to have no especial endowment, either of habits or structure, to enable them to seize fruits; and in this respect they are similar to the Toucans, if we leave the bill out of question, both tribes having heavy bodies, with feeble organs of flight, so that they are disabled from taking their food on the wing. The purpose of the enormous bill here becomes evident. Barbets and Toucans are very closely related; indeed a genus has lately been discovered towards the head waters of the Amazons,[8] which tends to link the two families together; the superior length of the Toucan's bill gives it an advantage over the Barbet, with its small, conical beak; it can reach and devour immense quantities of fruit whilst remaining seated, and thus its heavy body and gluttonous appetite form no obstacles to the prosperity of the species. It is worthy of note, that the young of the Toucan has a very much smaller beak than the full-grown bird. The relation between the extraordinarily lengthened bill of the Toucan and its mode of obtaining food, is precisely similar to that between the long neck and lips of the Giraffe and the mode of browsing of the animal. The bill of the Toucan can scarcely be considered a very perfectly-formed instrument for the end to which it is applied, as here explained; but nature appears not to shape organs at once for the functions to which they are now adapted, but avails herself, here of one already-existing structure or instinct, there of another, according as they are handy when need for their further modification arises.
One day, whilst walking along the principal pathway in the woods near Ega, I saw one of these Toucans seated gravely on a low branch close to the road, and had no difficulty in seizing it with my hand. It turned out to be a runaway pet bird; no one, however, came to own it, although I kept it in my house for several months. The bird was in a half-starved and sickly condition, but after a few days of good living it recovered health and spirits, and became one of the most amusing pets imaginable. Many excellent accounts of the habits of tame Toucans, have been published, and therefore I need not describe them in detail, but I do not recollect to have seen any notice of their intelligence and confiding disposition under domestication, in which qualities my pet seemed to be almost equal to parrots. I allowed Tocáno to go free about the house, contrary to my usual practice with pet animals; he never, however, mounted my working-table after a smart correction which he received the first time he did so. He used to sleep on the top of a box in a corner of the room, in the usual position of these birds, namely, with the long tail laid right over on the back, and the beak thrust underneath the wing. He ate of everything that we eat; beef, turtle, fish, farinha, fruit, and was a constant attendant at our table—a cloth spread on a mat. His appetite was most ravenous, and his powers of digestion quite wonderful. He got to know the meal hours to a nicety, and we found it very difficult, after the first week or two, to keep him away from the dining-room, where he had become very impudent and troublesome. We tried to shut him out by enclosing him in the back-yard, which was separated by a high fence from the street on which our front door opened, but he used to climb the fence and hop round by a long circuit to the dining-room, making his appearance with the greatest punctuality as the meal was placed on the table. He acquired the habit, afterwards, of rambling about the street near our house, and one day he was stolen, so we gave him up for lost. But, two days afterwards, he stepped through the open doorway at dinner hour, with his old gait, and sly, magpie-like expression, having escaped from the house where he had been guarded by the person who had stolen him, and which was situated at the further end of the village.
The Curl-crested Toucan (Pteroglossus Beauharnaisii).—Of the four smaller Toucans or Arassarís found near Ega, the Pteroglossus flavirostris is perhaps the most beautiful in colours, its breast being adorned with broad belts of rich crimson and black; but the most curious species, by far, is the Curl-crested, or Beauharnais Toucan. The feathers on the head of this singular
bird are transformed into thin, horny plates, of a lustrous black colour, curled up at the ends, and resembling shavings of steel or ebony wood: the curly crest being arranged on the crown in the form of a wig. Mr. Wallace and I first met with this species, on ascending the Amazons, at the mouth of the Solimoens; from that point it continues as a rather common bird on the terra firma, at least on the south side of the river, as far as Fonte Boa, but I did not hear of its being found further to the west. It appears in large flocks in the forest near Ega in May and June, when it has completed its moult. I did not find these bands congregated at fruit-trees, but always wandering through the forest, hopping from branch to branch amongst the lower trees, and partly concealed amongst the foliage. None of the Arassarís, to my knowledge, make a yelping noise like that uttered by the larger Toucans (Ramphastos); the notes of the curl-crested species are very singular, resembling the croaking of frogs. I had an amusing adventure one day with these birds. I had shot one from a rather high tree in a dark glen in the forest, and leaving my gun leaning against a tree-trunk in the pathway, went into the thicket where the bird had fallen, to secure my booty. It was only wounded, and on my attempting to seize it, it set up a loud scream. In an instant, as if by magic, the shady nook seemed alive with these birds, although there was certainly none visible when I entered the thicket. They descended towards me, hopping from bough to bough, some of them swinging on the loops and cables of woody lianas, and all croaking and fluttering their wings like so many furies. Had I had a long stick in my hand I could have knocked several of them over. After killing the wounded one I rushed out to fetch my gun, but, the screaming of their companion having ceased, they remounted the trees, and before I could reload, every one of them had disappeared.
Insects.—Upwards of 7000 species of insects were found in the neighbourhood of Ega. I must confine myself, in this place, to a few remarks on the order Lepidoptera, and on the ants, several kinds of which, found chiefly on the Upper Amazons, exhibit the most extraordinary instincts.
I found about 550 distinct species of butterflies at Ega. Those who know a little of Entomology will be able to form some idea of the riches of the place in this department, when I mention that eighteen species of true Papilio (the swallow-tail genus) were found within ten minutes' walk of my house. No fact could speak more plainly for the surpassing exuberance of the vegetation, the varied nature of the land, the perennial warmth and humidity of the climate. But no description can convey an adequate notion of the beauty and diversity in form and colour of this class of insects in the neighbourhood of Ega. I paid especial attention to them, having found that this tribe was better adapted than almost any other group of animals or plants, to furnish facts in illustration of the modifications which all species undergo in nature, under changed local conditions. This accidental superiority is owing partly to the simplicity and distinctness of the specific characters of the insects, and partly to the facility with which very copious series of specimens can be collected and placed side by side for comparison. The distinctness of the specific characters is due probably to the fact that all the superficial signs of change in the organisation are exaggerated, and made unusually plain, by affecting the framework, shape, and colour of the wings, which, as many anatomists believe, are magnified extensions of the skin around the breathing orifices of the thorax of the insects. These expansions are clothed with minute feathers or scales, coloured in regular patterns, which vary in accordance with the slightest change in the conditions to which the species are exposed. It may be said, therefore, that on these expanded membranes Nature writes, as on a tablet, the story of the modifications of species, so truly do all changes of the organisation register themselves thereon. Moreover, the same colour-patterns of the wings generally show, with great regularity, the degrees of blood-relationship of the species. As the laws of Nature must be the same for all beings, the conclusions furnished by this group of insects must be applicable to the whole organic world; therefore, the study of butterflies—creatures selected as the types of airiness and frivolity—instead of being despised, will some day be valued as one of the most important branches of Biological science.
I have mentioned, in a former chapter, the general sultry condition of the atmosphere on the Upper Amazons, where the sea-breezes which blow from Pará to the mouth of the Rio Negro (1000 miles up stream) are unknown. This simple difference of meteorological conditions would hardly be thought to determine what genera of butterflies should inhabit each region, yet it does so in a very decisive manner. The Upper Amazons, from Ega upwards, and the eastern slopes of the Andes, whence so large a number of the most richly-coloured species of this tribe have been received in Europe, owe the most ornamental part of their insect population to the absence of strong and regular winds. Nineteen of the most handsome genera of Ega, containing altogether about 100 species, are either entirely absent or very sparingly represented on the Lower Amazons within reach of the trade winds. The range of these nineteen genera is affected by a curiously complicated set of circumstances. In all the species of which they are composed, the males are more than 100 to one more numerous than the females, and being very richly coloured, whilst the females are of dull hues, they spend their lives in sporting about in the sunlight, imbibing the moisture which constitutes their food, from the mud on the shores of streams, their spouses remaining hid in the shades of the forest. The very existence of these species depends on the facilities which their males have for indulgence in the pleasures of this sunshiny life. The greatest obstacle to this is the prevalence of strong winds, which not only dries rapidly all moisture in open places, but prevents the richly-attired dandies from flying daily to their feeding-places. I noticed this particularly whilst residing at Santarem, where the moist margins of water, localities which on the Upper Amazons swarm with these insects, were nearly destitute of them; and at Villa Nova (where a small number exists) I have watched them buffeting with the strong winds at the commencement of the dry season, and, as the dryness increased, disappearing from the locality. On ascending the Tapajos to the calm and sultry banks of the Cuparí, a great number of these insects re-appeared, most of them being the same as those found on the Upper Amazons, thus showing clearly that their existence in the district depended on the absence of winds.
Before proceeding to describe the ants, a few remarks may be made on the singular cases and cocoons woven by the caterpillars of certain moths found at Ega.
Suspended cocoon
of Moth.
The first that may be mentioned, is one of the most beautiful examples of insect workmanship I ever saw. It is a cocoon, about the size of a sparrow's egg, woven by a caterpillar in broad meshes of either buft or rose-coloured silk, and is frequently seen in the narrow alleys of the forest, suspended from the extreme tip of an outstanding leaf by a strong silken thread five or six inches in length. It forms a very conspicuous object, hanging thus in midair. The glossy threads with which it is knitted are stout, and the structure is therefore not liable to be torn by the beaks of insectivorous birds, whilst its pendulous position makes it doubly secure against their attacks, the apparatus giving way when they peck at it. There is a small orifice at each end of the egg-shaped bag, to admit of the escape of the moth when it changes from the little chrysalis which sleeps tranquilly in its airy cage. The moth is of a dull slaty colour and belongs to the Lithosiide group of the silk-worm family (Bombycidæ). When the caterpillar begins its work, it lets itself down from the tip of the leaf which it has chosen, by spinning a thread of silk, the thickness of which it slowly increases as it descends. Having given the proper length to the cord, it proceeds to weave its elegant bag, placing itself in the centre and spinning rings of silk at regular intervals, connecting them at the same time by means of cross threads; so that the whole, when finished, forms a loose web, with quadrangular meshes of nearly equal size throughout. The task occupies about four days: when finished, the enclosed caterpillar becomes sluggish, its skin shrivels and cracks, and there then remains a motionless chrysalis of narrow shape, leaning against the sides of its silken cage.
Many other kinds are found at Ega belonging to the same cocoon-weaving family, some of which differ from the rest in their caterpillars possessing the art of fabricating cases with fragments of wood or leaves, in which they live secure from all enemies whilst they are feeding and growing. I saw many species of these; some of them knitted together, with fine silken threads, small bits of stick, and so made tubes similar to those of caddice-worms; others (Saccophora) chose leaves for the same purpose, forming with them an elongated bag open at both ends, and having the inside lined with a thick web. The tubes of full-grown caterpillars of Saccophora are two inches in length, and it is at this stage of growth, that I have generally seen them. They feed on the leaves of Melastomæ, and as, in crawling, the weight of so large a dwelling would be greater than the contained caterpillar could sustain, the insect
attaches the case by one or more threads to the leaves or twigs near which it is feeding.
Foraging Ants.—Many confused statements have been published in books of travel, and copied in Natural History works, regarding these ants, which appear to have been confounded with the Saüba, a sketch of whose habits has been given in the first chapter of this work. The Saüba is a vegetable feeder, and does not attack other animals; the accounts that have been published regarding carnivorous ants which hunt in vast armies, exciting terror wherever they go, apply only to the Ecitons, or foraging ants, a totally different group of this tribe of insects. The Ecitons are called Tauóca by the Indians, who are always on the look-out for their armies when they traverse the forest, so as to avoid being attacked. I met with ten distinct species of them, nearly all of which have a different system of marching; eight were new to science when I sent them to England. Some are found commonly in every part of the country, and one is peculiar to the open campos of Santarem; but, as nearly all the species are found together at Ega, where the forest swarmed with their armies, I have left an account of the habits of the whole genus for this part of my narrative. The Ecitons resemble, in their habits, the Driver-ants of Tropical Africa; but they have no close relationship with them in structure, and indeed belong to quite another sub-group of the ant-tribe.
Like many other ants, the communities of Ecitons are composed, besides males and females, of two classes of workers, a large-headed (worker-major) and a small-headed (worker-minor) class; the large-heads have, in some species, greatly lengthened jaws, the small-heads have jaws always of the ordinary shape; but the two classes are not sharply-defined in structure and function, except in two of the species. There is, in all of them a little difference amongst the workers regarding the size of the head; but in some species (E. legionis) this is not sufficient to cause a separation into classes, with division of labour; in others (E. hamata) the jaws are so monstrously lengthened in the worker-majors, that they are incapacitated from taking part in the labours which the worker-minors perform; and again, in others (E. erratica and E. vastator), the difference is so great that the distinction of classes becomes complete, one acting the part of soldiers, and the other that of workers.[9] The peculiar feature in the habits of the Eciton genus is their hunting for prey in regular bodies, or armies. It is this which chiefly distinguishes them from the genus of common red stinging-ants (Myrmica), several species of which inhabit England, whose habit is to search for food in the usual irregular manner. All the Ecitons hunt in large organised bodies; but almost every species has its own special manner of hunting.
Eciton rapax.—One of the foragers, Eciton rapax, the giant of its genus, whose worker-majors are half-an-inch in length, hunts in single file through the forest. There is no division into classes amongst its workers, although the difference in size is very great, some being scarcely one-half the length of others. The head and jaws, however, are always of the same shape, and a gradation in size is presented from the largest to the smallest, so that all are able to take part in the common labours, of the colony. The chief employment of the species seems to be plundering the nests of a large and defenceless ant of another genus (Formica), whose mangled bodies I have often seen in their possession, as they were marching away. The armies of Eciton rapax are never very numerous.
Eciton legionis.—Another species, E. legionis, agrees with E. rapax in having workers not rigidly divisible into two classes; but it is much smaller in size, not differing greatly, in this respect, from our common English red ant (Myrmica rubra), which it also resembles in colour. The Eciton legionis lives in open places, and was seen only on the sandy campos of Santarem. The movements of its hosts were, therefore, much more easy to observe than those of all other kinds, which inhabit solely the densest thickets; its sting and bite, also, were less formidable than those of other species. The armies of E. legionis consist of many thousands of individuals, and move in rather broad columns. They are just as quick to break line, on being disturbed, and attack hurriedly and furiously any intruding object as the other Ecitons. The species is not a common one, and I seldom had good opportunities of watching its habits. The first time I saw an army, was one evening near sunset. The column consisted of two trains of ants, moving in opposite directions; one train empty-handed, the other laden with the mangled remains of insects, chiefly larvæ and pupæ of other ants. I had no difficulty in tracing the line to the spot from which they were conveying their booty: this was a low thicket; the Ecitons were moving rapidly about a heap of dead leaves; but as the short tropical twilight was deepening rapidly, and I had no wish to be benighted on the lonely campos, I deferred further examination until the next day.
On the following morning, no trace of ants could be found near the place where I had seen them the preceding day, nor were there signs of insects of any description in the thicket; but at the distance of eighty or one hundred yards, I came upon the same army, engaged, evidently, on a razzia of a similar kind to that of the previous evening; but requiring other resources of their instinct, owing to the nature of the ground. They were eagerly occupied, on the face of an inclined bank of light earth, in excavating mines, whence, from a depth of eight or ten inches, they were extracting the bodies of a bulky species of ant, of the genus Formica. It was curious to see them crowding round the orifices of the mines, some assisting their comrades to lift out the bodies of the Formicas, and others tearing them in pieces, on account of their weight being too great for a single Eciton; a number of carriers seizing each a fragment, and carrying it off down the slope. On digging into the earth with a small trowel near the entrances of the mines, I found the nests of the Formicæ, with grubs and cocoons, which the Ecitons were thus invading, at a depth of about eight inches from the surface. The eager freebooters rushed in as fast as I excavated, and seized the ants in my fingers as I picked them out, so that I had some difficulty in rescuing a few entire for specimens. In digging the numerous mines to get at their prey, the little Ecitons seemed to be divided into parties, one set excavating, and another set carrying away the grains of earth. When the shafts became rather deep, the mining parties had to climb up the sides each time they wished to cast out a pellet of earth; but their work was lightened for them by comrades, who stationed themselves at the mouth of the shaft, and relieved them of their burthens, carrying the particles, with an appearance of foresight which quite staggered me, a sufficient distance from the edge of the hole to prevent them from rolling in again. All the work seemed thus to be performed by intelligent cooperation amongst the host of eager little creatures; but still there was not a rigid division of labour, for some of them, whose proceedings I watched, acted at one time as carriers of pellets, and at another as miners, and all shortly afterwards assumed the office of conveyors of the spoil.
In about two hours, all the nests of Formicæ were rifled, though not completely, of their contents, and I turned towards the army of Ecitons, which were carrying away the mutilated remains. For some distance there were many separate lines of them moving along the slope of the bank; but a short distance off, these all converged, and then formed one close and broad column, which continued for some sixty or seventy yards, and terminated at one of those large termitariums already described in a former chapter as being constructed of a material as hard as stone. The broad and compact column of ants moved up the steep sides of the hillock in a continued stream; many, which had hitherto trotted along empty-handed, now turned to assist their comrades with their heavy loads, and the whole descended into a spacious gallery or mine, opening on the top of the termitarium. I did not try to reach the nest, which I supposed to lie at the bottom of the broad mine, and therefore in the middle of the base of the stony hillock.
Eciton drepanophora.—The commonest species of foraging ants are the Eciton hamata and E. drepanophora, two kinds which resemble each other so closely that it requires attentive examination to distinguish them;
yet their armies never intermingle, although moving in the same woods and often crossing each other's tracks. The two classes of workers look, at first sight, quite distinct, on account of the wonderful amount of difference between the largest individuals of the one, and the smallest of the other. There are dwarfs not more than one-fifth of an inch in length, with small heads and jaws, and giants half an inch in length with monstrously enlarged head and jaws, all belonging to the same family. There is not, however, a distinct separation of classes, individuals existing which connect together the two extremes. These Ecitons are seen in the pathways of the forest at all places on the banks of the Amazons, travelling in dense columns of countless thousands. One or other of them is sure to be met with in a woodland ramble, and it is to them probably, that the stories we read in books on South America apply, of ants clearing houses of vermin, although I heard of no instance of their entering houses, their ravages being confined to the thickest parts of the forest.
When the pedestrian falls in with a train of these ants, the first signal given him is a twittering and restless movement of small flocks of plain-coloured birds (ant-thrushes) in the jungle. If this be disregarded until he advances a few steps further, he is sure to fall into trouble, and find himself suddenly attacked by numbers of the ferocious little creatures. They swarm up his legs with incredible rapidity, each one driving its pincer-like jaws into his skin, and with the purchase thus obtained, doubling in its tail, and stinging with all its might. There is no course left but to run for it; if he is accompanied by natives they will be sure to give the alarm, crying "Tauóca!" and scampering at full speed to the other end of the column of ants. The tenacious insects who have secured themselves to his legs then have to be plucked off one by one, a task which is generally not accomplished without pulling them in twain, and leaving heads and jaws sticking in the wounds.
The errand of the vast ant-armies is plunder, as in the case of Eciton legionis; but from their moving always amongst dense thickets, their proceedings are not so easy to observe as in that species. Wherever they move, the whole animal world is set in commotion, and every creature tries to get out of their way. But it is especially the various tribes of wingless insects that have cause for fear, such as heavy-bodied spiders, ants of other species, maggots, caterpillars, larvæ of cockroaches and so forth, all of which live under fallen leaves, or in decaying wood. The Ecitons do not mount very high on trees, and therefore the nestlings of birds are not much incommoded by them. The mode of operation of these armies, which I ascertained only after long-continued observation, is as follows. The main column, from four to six deep, moves forward in a given direction, clearing the ground of all animal matter dead or alive, and throwing off here and there, a thinner column to forage for a short time on the flanks of the main army, and re-enter it again after their task is accomplished. If some very rich place be encountered anywhere near the line of march, for example, a mass of rotten wood abounding in insect larvæ, a delay takes place, and a very strong force of ants is concentrated upon it. The excited creatures search every cranny and tear in pieces all the large grubs they drag to light. It is curious to see them attack wasps' nests, which are sometimes built on low shrubs. They gnaw away the papery covering to get at the larvæ, pupæ, and newly-hatched wasps, and cut everything to tatters, regardless of the infuriated owners which are flying about them. In bearing off their spoil in fragments, the pieces are apportioned to the earners with some degree of regard to fairness of load: the dwarfs taking the smallest pieces, and the strongest fellows with small heads the heaviest portions. Sometimes two ants join together in carrying one piece, but the worker-majors with their unwieldy and distorted jaws, are incapacitated from taking any part in the labour. The armies never march far on a beaten path, but seem to prefer the entangled thickets where it is seldom possible to follow them. I have traced an army sometimes for half a mile or more, but was never able to find one that had finished its day's course and returned to its hive. Indeed, I never met with a hive; whenever the Ecitons were seen, they were always on the march.
I thought one day, at Villa Nova, that I had come upon a migratory horde of this indefatigable ant. The place was a tract of open ground near the river side, just outside the edge of the forest, and surrounded by rocks and shrubbery. A dense column of Ecitons was seen extending from the rocks on one side of the little haven, traversing the open space, and ascending the opposite declivity. The length of the procession was from sixty to seventy yards, and yet neither van nor rear was visible. All were moving in one and the same direction, except a few individuals on the outside of the column, which were running rearward, trotting along for a short distance, and then turning again to follow the same course as the main body. But these rearward movements were going on continually from one end to the other of the line, and there was every appearance of their being a means of keeping up a common understanding amongst all the members of the army, for the retrograding ants stopped very often for a moment to touch one or other of their ownward-moving comrades with their antennæ; a proceeding which has been noticed in other ants, and supposed to be their mode of conveying intelligence. When I interfered with the column or abstracted an individual from it, news of the disturbance was very quickly communicated to a distance of several yards towards the rear, and the column at that point commenced retreating. All the small-headed workers carried in their jaws a little cluster of white maggots, which I thought, at the time, might be young larvæ of their own colony, but afterwards found reason to conclude were the grubs of some other species whose nests they had been plundering, the procession being most likely not a migration, but a column on a marauding expedition.
The position of the large-headed individuals in the marching column was rather curious. There was one of these extraordinary fellows to about a score of the smaller class; none of them carried anything in their mouths, but all trotted along empty-handed and outside the column, at pretty regular intervals from each other, like subaltern officers in a marching regiment of soldiers. It was easy to be tolerably exact in this observation, for their shining white heads made them very conspicuous amongst the rest, bobbing up and down as the column passed over the inequalities of the road. I did not see them change their position, or take any notice of their small-headed comrades marching in the column, and when I disturbed the line, they did not prance forth or show fight so eagerly as the others. These large-headed members of the community have been considered by some authors as a soldier class, like the similarly-armed caste in Termites; but I found no proof of this, at least in the present species, as they always seemed to be rather less pugnacious than the worker-minors, and their distorted jaws disabled them from fastening on a plane surface like the skin of an attacking animal. I am inclined, however, to think that they may act, in a less direct way, as protectors of the community, namely, as indigestible morsels to the flocks of ant-thrushes which follow the marching columns of these Ecitons, and are the most formidable enemies of the species. It is possible that the hooked and twisted jaws of the large-headed class may be effective weapons of annoyance when in the gizzards or stomachs of these birds, but I unfortunately omitted to ascertain whether this was really the fact.
The life of these Ecitons is not all work, for I frequently saw them very leisurely employed in a way that looked like recreation. When this happened, the place was always a sunny nook in the forest. The main column of the army and the branch columns, at these times, were in their ordinary relative positions; but, instead of pressing forward eagerly, and plundering right and left, they seemed to have been all smitten with a sudden fit of laziness. Some were walking slowly about, others were brushing their antennæ with their fore-feet; but the drollest sight was their cleaning one another. Here and there an ant was seen stretching forth first one leg and then another, to be brushed or washed by one or more of its comrades, who performed the task by passing the limb between the jaws and the tongue, finishing by giving the antennæ a friendly wipe. It was a curious spectacle, and one well calculated to increase one's amazement at the similarity between the instinctive actions of ants and the acts of rational beings, a similarity which must have been brought about by two different processes of development of the primary qualities of mind. The actions of these ants looked like simple indulgence in idle amusement. Have these little creatures, then, an excess of energy beyond what is required for labours absolutely necessary to the welfare of their species, and do they thus expend it in mere sportiveness, like young lambs or kittens, or in idle whims like rational beings? It is probable that these hours of relaxation and cleaning may be indispensable to the effective performance of their harder labours, but whilst looking at them, the conclusion that the ants were engaged merely in play was irresistible.
Eciton prædator.—This is a small dark-reddish species, very similar to the common red stinging-ant of England. It differs from all other Ecitons in its habit of hunting, not in columns, but in dense phalanxes consisting of myriads of individuals, and was first met with at Ega, where it is very common. Nothing in insect movements is more striking than the rapid march of these large and compact bodies. Wherever they pass all the rest of the animal world is thrown into a state of alarm. They stream along the ground and climb to the summits of all the lower trees, searching every leaf to its apex, and whenever they encounter a mass of decaying vegetable matter, where booty is plentiful, they concentrate, like other Ecitons, all their forces upon it, the dense phalanx of shining and quickly-moving bodies, as it spreads over the surface, looking like a flood of dark-red liquid. They soon penetrate every part of the confused heap, and then, gathering together again in marching order, onward they move. All soft-bodied and inactive insects fall an easy prey to them, and, like other Ecitons, they tear their victims in pieces for facility of carriage. A phalanx of this species, when passing over a tract of smooth ground, occupies a space of from four to six square yards; on examining the ants closely they are seen to move, not altogether in one straightforward direction, but in variously-spreading contiguous columns, now separating a little from the general mass, now re-uniting with it. The margins of the phalanx spread out at times like a cloud of skirmishers from the flanks of an army. I was never able to find the hive of this species.
Blind Ecitons.—I will now give a short account of the blind species of Eciton. None of the foregoing kinds have eyes of the facetted or compound structure such as are usual in insects, and which ordinary ants (Formica) are furnished with, but all are provided with organs of vision composed each of a single lens. Connecting them with the utterly blind species of the genus, is a very stout-limbed Eciton, the E. crassicornis, whose eyes are sunk in rather deep sockets. This ant goes on foraging expeditions like the rest of its tribe, and attacks even the nests of other stinging species (Myrmica), but it avoids the light, moving always in concealment under leaves and fallen branches. When its columns have to cross a cleared space, the ants construct a temporary covered way with granules of earth, arched over, and holding together mechanically; under this the procession passes in secret, the indefatigable creatures repairing their arcade as fast as breaches are made in it.
Next in order comes the Eciton vastator, which has no eyes, although the collapsed sockets are plainly visible;
and, lastly, the Eciton erratica, in which both sockets and eyes have disappeared, leaving only a faint ring to mark the place where they are usually situated. The armies of E. vastator and E. erratica move, as far as I could learn, wholly under covered roads, the ants constructing them gradually but rapidly as they advance. The column of foragers pushes forward step by step, under the protection of these covered passages, through the thickets, and on reaching a rotting log, or other promising hunting-ground, pour into the crevices in search of booty. I have traced their arcades, occasionally, for a distance of one or two hundred yards; the grains of earth are taken from the soil over which the column is passing, and are fitted together without cement. It is this last-mentioned feature that distinguishes them from the similar covered roads made by Termites, who use their glutinous saliva to cement the grains together. The blind Ecitons, working in numbers, build up simultaneously the sides of their convex arcades, and contrive, in a surprising manner, to approximate them and fit in the key-stones without letting the loose uncemented structure fall to pieces. There was a very clear division of labour between the two classes of neuters in these blind species. The large-headed class, although not possessing monstrously-lengthened jaws like the worker-majors in E. hamata and E. drepanophora, are rigidly defined in structure from the small-headed class, and act as soldiers, defending the working community (like soldier Termites) against all comers. Whenever I made a breach in one of their covered ways, all the ants underneath were set in commotion, but the worker-minors remained behind to repair the damage, whilst the large-heads issued forth in a most menacing manner, rearing their heads and snapping their jaws with an expression of the fiercest rage and defiance.
The armies of all Ecitons are accompanied by small swarms of a kind of two-winged fly, the females of which have a very long ovipositor, and which belongs to the genus Stylogaster (family Conopsidæ). These swarms hover with rapidly-vibrating wings, at a height of a foot or less from the soil over which the Ecitons are moving, and occasionally one of the flies darts with great quickness towards the ground. I found they were not occupied in transfixing ants, although they have a long needle-shaped proboscis, which suggests that conclusion, but most probably in depositing their eggs in the soft bodies of insects, which the ants were driving away from their hiding-places. These eggs would hatch after the ants had placed their booty in their hive as food for their young. If this supposition be correct, the Stylogaster would offer a case of parasitism of quite a novel kind. Flies of the genus Tachinus exhibit a similar instinct, for they lie in wait near the entrances to bees' nests, and slip their eggs into the food which the deluded bees are in the act of conveying for their young.
- ↑ Three pounds seven shillings to four pounds thirteen shillings.
- ↑ False molars, or premolars, differ from true molars, through being preceded in growth by milk teeth.
- ↑ True Lemurs, Tarsiens, Aye-Ayes, and Galeopitheci.
- ↑ The remains of insects belonged to species of Scarites (Coleoptera) having blunt maxillary blades, several of which fly abroad in great numbers on warm nights.
- ↑ Tachyphonus surinamus and cristatus, Tanagrella elegantissima. I very often found fruit-eating birds, such as Cassicus icteronotus and Capito Amazoninus mingled with these bands.
- ↑ Ramphastos Cuvieri, Pteroglossus Beauharnaisii, Pt. Langsclorfii, Pt. castanotis, Pt. flavirostris. Further westward, namely, near St. Paulo, a sixth species makes its appearance, the Pteroglossus Humboldtii.
- ↑ Capitoninæ, G. E. Cray.
- ↑ Tetragonops. Dr. Sclater has lately given a figure of this bird in the Ibis, vol. iii. p. 182.
- ↑ There is one numerous genus of South American ants in which the two classes of workers are nearly always sharply defined in structure, not only the head, but other parts of the body, being strikingly different. This is the genus Cryptocerus, of which I found fifteen species, but in no case was able to discover the distinctive function of the worker-major class. The contrast between the two classes reaches its acme in C. discocephalus, whose worker-majors have a strange dish-shaped expansion on the crown of the head. All the species inhabit hollow twigs or branches of trees, the monstrous-headed individuals being always found quiescent and mixed with crowds of worker-minors. It cannot be considered wonderful that the function of worker-majors has not been discovered in exotic ants, when Huber, who devoted a life-time to the study of European ants, was unable to detect it in a common species, the Formica rufescens.