NATURALIST ON THE RIVER AMAZONS. 



62ft 



habits between these two classes form an in- 

 teresting but very difficult study. It is one 

 of the great p( culiarities of the Saiiba ant to 

 possess three classes of workers. My inves- 

 tigations regarding them were far from com- 

 plete ; I will relate, however, what I have 

 observed on the subject. 



When engaged in leaf-cutting, plundering 

 farinha, and other operations, two classes of 

 ^workers are always seen (Figs. 1 and 2, 

 page 3). They are not, it is true, very 

 sharply defined in structure, for individuals 

 of intermediate grades occur. All the woik, 

 however, is done by the individuals which 

 have small heads (Fig. 1), while those which 

 have enormously large heads, the worker- 

 majors (Fig. 2) % are observed to be simply 

 walking about. I could never satisfy myself 

 as to the function of these worker-majors. 

 They are not the soldiers or defenders of 1 the 

 working portion of the community, like the 

 armed class in the Termites, or white ants ; 

 for they never fight. The species has no 

 sting, and does not display active resistance 

 when interfered with. I once imagined they 

 exercised a sort of superintendence over the 

 -others ; but this function is entirely unneces- 

 sary in a community where all work with a 

 precision and regularity resembling the sub- 

 ordinate parts of a piece of machinery. I 

 came to the conclusion, at last, that they 

 huve no very precisely defined function. 

 ' They cannot, however, be entirely useless to 

 the community, for the sustenance of an idle 

 class of such bulky individuals would be too 

 heavy a charge for the species to sustain. I 

 think they serve, in some sort, as passive in- 

 : struments of protection to the real workers. 

 Their enormously large, hard, and indestruc- 

 tible heads may be of use in protecting them 

 tigainst the attacks of insectivorous animals. 

 They would be, on this view, a kind ol 

 "pieces de resistance," serving as a foil 

 against onslaughts made on the main body of 

 workers. 



The third order of workers is the most 

 curious of all. If the top of a small fresh 

 .hillock, one in which the thatching process 

 is going on, be taken off, a broad cylindrical 

 shaft is disclosed, at a depth of about two 

 feet from the surface. If this be probed with 

 a stick, which may be done to the extent of 

 1hree or four feet without touching bottom, 

 a small number of colossal fellows (Fig. 3) 

 ^will slowly begin to make their way up the 

 smooth sides of the mine. Their heads are 

 of the same size as those of the class Fig. 2 ; 

 but the front is clolhed with hairs, instead of 

 being polished, and they have in the middle 

 of the forehead a twin ocellus, or simple eye, 

 of quite different structure from the ordinary 

 C"mpound eyes on the sides of the head. 

 This frontal eye is totally wanting in the 

 ^tiier workers, and is not known in any other 

 kind of ant. The apparition of these strange 

 creatures from the cavernous depths of the 

 mine reminded me, when I first observed 

 them, of the Cyclopes of Homeric fable. 

 They were not very pugnacious, as I feared 

 they would be, and I had no difflculty__in 



^securing a few with my fingers. I never saw 

 them under any other circumstances than 

 those here related, and what their special 

 functions may be I cannot divine. 



The whole arrangement of a Formicarium, 

 or ant-colony, and all the varied activity of 

 ant-life, are directed to one main purpose 

 the perpetuation and dissemination of the 

 species. Most of the labor which we see per- 

 formed by the workers has for its end the 

 sustenance and welfare of the young brood, 

 which are helpless grubs. The true females 

 are incapable of attending to the wants of 

 their offspring ; and it is on the poor sterile 

 workers, who are- denied all the other pleas- 

 ures of maternity, that the entire care de- 

 volves. The workers are also the chief agents 

 in carrying out the different migrations of 

 the colonies, which are of vast importance to 

 the dispersal and consequent prosperity of 

 the species. The successful debut of the 

 winged males and females depends likewise 

 on the workers. It is amusing to see the ac- 

 tivity and excitement which reign in an ant's 

 nest when the exodus of the* winged individ- 

 uals is taking place. The workers clear ths 

 roads of exit, and show the most lively inter- 

 est in their departure, although it is highly 

 improbable that any of them will return to 

 the same colony. The swarming or exodus 

 of the winged males and females of the Saiiba 

 ant takes place in January and February, that 

 is, at the commencement of the rainy sea- 

 son. They come out in the evening in vast 

 numbers, causing qu : te a commotion in the 

 streets and lanes. They are of very large 

 size, the female measuring no less than two 

 inches and a quarter in expanse of wing ; 

 the male is not much more than half this size. 

 They are so eagerly preyed upon by insectiv- 

 orous animals that on the morning after their 

 flight not an individual is to be seen, a few 

 impregnated females alone escaping the 

 slaughter to found new colonies. 



At the time of our arrival, Para had not 

 quite recovered from the effects of a series of 

 revolutions, brought about by the hatred 

 which existed between the native Brazilians 

 and the Portuguese ; the former, in the end, 

 calling to their aid the Indian and mixed col- 

 ored population. The number of inhabitants 

 of the city had decreased, in consequence of 

 these disorders, from 24,500 in 1819, to 15,- 

 000 in 1848. Although the public peace had 

 not been broken for twelve years before the 

 date of our visit, confidence was not yet 

 completely restored, and the Portuguese 

 merchants and tradesmen would not trust 

 themselves to live at their beautiful country- 

 houses or rocinhas, which lie embosomed in 

 the luxuriant shady gardens around the city. 

 No progress had been made in clearing the 

 second growth forest, which had grown over 

 the once cultivated grounds and now reached 

 the end of all the suburban streets. The 

 place had the aspect of one which had seen 

 better days ; the public buildings, including 

 the palaces of the President and Bishop, the 

 cathedral, the principal churches and con- 

 ventsi all seemed constructed on u scale of 



