296 J. C. BRANNER — DECOMPOSITION OF ROCKS IN BRAZIL. 



anastomose in every direction, and into these galleries and chambers 

 they carry great quantities of leaves. One can get some idea of the ex- 

 tent of these openings from the heaps of earth brought up by the insects. 

 These mounds are often from 50 to 100 feet long, from 10 to 20 feet across? 

 and from 1 to 4 feet high,* and contain tons of eartli. The underground 

 galleries of the sadbas penetrate the soil to great distances. These ants 

 are very injurious to vegetation, and one of the methods used by the 

 planters to kill them is to blow poisonous fumes into their burrows. I 

 have seen these fumes blown into one of these openings issue several 

 hundred, even 1,000 feet, away. Mr Charles J. DuUey, of Sao Paulo, tells 

 me that he has observed openings 600 feet from the paneUa or chief 

 nucleus. A gallery of equal length on the opposite side would give a 

 horizontal width of their galleries of 1,200 feet. Bates saw sadba galleries 

 in the Botanical Gardens of Para 70 yards long. He says, on the authority 

 of the Reverend H. Clark, that ants tunneled beneath the Parahyba river.f 

 Bates also tells of the fire-ants at Aveyros on the Amazonas actually 

 driving the inhabitants out of that town. 



" The soil of the whole village is undermined by them ; the ground is perforated 

 with entrances to their subterranean galleries." 



And yet when the young winged ants come from their nests at the 

 beginning of the rainy season they are blown into the river and drowned 

 in such numbers that a " compact heap of dead bodies . . . extends 

 along the banks of the river for 12 or 15 miles." X 



Clark says : § 



" Brazil is one great ants' nest. They are of all sizes and dispositions : some are 

 a plague to us in the house, for they will come at nights and prey on the insects in 

 our store-boxes ; some are a plague to us in the forests, for they get inside one's 

 clothes and bite and sting; others are a more serious evil still — vegetable feeders^ 

 which will take a fancy to the leaves of some tree and strip every leaf off in one 

 ni^ht. Some species . . . burrow for miles six or ten feet below the surface 

 of the ground." 



Another writer says : 



"The multiplication of these insects is so rapid, their retreats so inaccessible, 

 their organization so perfect, and their mandibles so audacious that one seriously 

 asks whether they are not the real conquerors of Brazil. . . . One may see 

 colonists giving way before these indefatigable invaders every day." || 



* Wallace mentions heaps from 30 to 40 feet long and 4 feet high. A Narrative of Travel on the 

 Amazon and Rio Negro. Alfred R. Wallace. London, 1870, p. .37. C. Brent mentions a mound 

 45 feet acros.s and 2 feet high. American Naturalist, vol. xx, 1886, p. 124. 



t Naturalist on the Amazonas. Henry W. Bates. 4th ed., pp. 9-1.5. 



X Naturalist on the Amazonas, 4th ed., p. 206. See also pp. 350-360. 



i Letters Home from Spain, Algeria and Brazil. Reverend Hamlet Clark. London, 1867, pp. 131, 

 173. The Zoologist, Maj', 1857, p. 5561. 



II Le Mato Virgem ; scenes et souvenirs d'un voyage au Bresil. Adolphe d'Assier. Revue des 

 Deux Mondes, xlix, i, 1864, p. 582. 



