1907.] Wheeler, Fungus-growing Ants of North America. 675 



nests and describes the "soft grey spongy substance, apparently leaves, 

 finely triturated and mixed with an animal secretion," found in the chambers. 

 This "animal secretion" was undoubtedly the web of fungus hyphte which 

 binds the leaf particles together. 



Bates (1S63) in his classical 'Naturalist on the xVmazon' gives an excel- 

 lent account of Atta cepJialotes, one of the ants called "Saubas" by the 

 Brazilians. He described the extensive earthworks of this species, "large 

 mounds of earth of a different color from the surrounding soil, which were 

 thrown up in the plantations and woods. Some of these were very extensive, 



being forty yards in circumference, but not more than two feet in height 



The difference in color from the superficial soil of the vicinity is owing to 

 their being formed of the subsoil, brought up from a considerable depth." 

 He describes the manner in which the ants cut out pieces of leaves and the 

 ensuing damage to cultivated trees and shrubs, and believes that "the leaves 

 are used to thatch the domes which cover the entrances to their subterranean 

 dwellings, thereby protecting from the deluging rains the young broods 

 in the nests beneath." This erroneous inference was derived from seeing 

 the workers "troop up" and cast their pieces of leaves on the hillocks of the 

 nest where some of them are often covered by the earth brought up by the 

 excavating workers. Bates also records the following observation to show 

 the extent of the subterranean burrows of the Sauba: "The Rev. Hamlet 

 Clark has related that the Saiiba of Rio de Janeiro, a species closely allied 

 to ours, has excavated a tunnel under the bed of the river Parahyba, at a 

 place where it is as broad as the Thames at London Bridge. At the Magaory 

 rice mills, near Para, these ants once pierced the embankment of a large 

 reservoir: the great body of water Avhich it contained escaped before the 

 damage could be repaired. In the Botanic Gardens at Para, an enterprising 

 French gardener tried all he could think of to extirpate the saiiba. With 

 this object he made fires over some of the main entrances to their colonies 

 and blew the fumes of sulphur down the galleries by means of bellows. I 

 saw the smoke issue from a great number of outlets, one of which was 70 

 yards distant from the place where the bellows were used." This ant not 

 only does great damage to the foliage but also plunders stores of vegetable 

 provisions such as farina or mandioca meal in houses at night. Bates 

 observed the division of labor among the castes although he did not accurately 

 define the soldier, or worker major. From the fact that the latter are often 

 seen to be simply stalking about, he concluded that their "enormously large, 

 hard and indestructible heads may be of use in protecting them against the 

 attacks of insectivorous animals. They would be, in this view, a kind of 

 'pieces de resistance,' serving as a foil again.st on.slaughts made on the main 

 body of workers." Had Bates undertaken to excavate a large colonv of 



