GEOLOGIC WORK OF ANTS BRANNEK. 319 



Sampaio, a Brazilian entomologist who has given much attention to 

 the sauba ants, shows one burrow as much as 3.5 meters below the 

 surface. 1 



Dr. Jaoquim Lustosa, of Lafayette, State of Minas Geraes, Brazil, 

 writes : 



Competent persons assure me that the true ants burrow to a depth of 10 meters 

 or more, and that they exhibit a strange and remarkable intelligence, and that they 

 even cros3 wide and deep streams by means of tunnels so deep as to avoid the infiltra- 

 tion of the water. 



The length of the tunnels has often been demonstrated by forcing 

 smoke through them. I have myself seen fumes blown- into one 

 opening and issuing from others as much as 300 meters away. 



Ants 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 Magoary rice mills, near Para, these ants once pierced the 

 embankment of a large reservoir; the great body of water which it 

 contained escaped before the damage could be repaired. 2 



Another writer, Rev. J. C. Wood, tells of the saubas having "ruined 

 a gold mine for a time, breaking into it with a tunnel some 80 yards 

 in length and letting in a torrent of water, which broke down the 

 machinery and washed away all the supports, so that the mine had 

 to be dug afresh." 3 



The diameter of an underground passage varies from 1 or 2 centi- 

 meters up to 5 centimeters or more. They widen out and narrow 

 down without any apparent reason, and those made by the saubas 

 that have been examined have here and there local enlargements that 

 are commonly from 1 to 2 decimeters in height and from 1 to 3 deci- 

 meters in length. These chambers, when freshly opened, I have 

 generally found filled, or partly filled, with loose, moldy masses of 

 dead leaves. 



Belt describes the underground passages in Nicaragua as follows: 4 



In our mining operations we also, on two occasions, carried our excavations from 

 below up through very large formicariums, so that all their underground workings 

 were exposed to observation. I found their nests below to consist of numerous 

 rounded chambers, about as large as a man's head, connected together by tunneled 

 passages leading from one chamber to another. 



RELATIONS TO THE SOIL. 



The distribution of ant colonies as shown by their mounds suggests, 

 if it does not prove beyond question, that the character of the soil has 

 an important influence on the distribution of the ants themselves. 



1 A. G. de Azevedo Sampaio: Sauva ou Manhu-uara, pp. 22, 52, 64. Sao Paulo, 1894. 



2 H. W. Bates: Naturalist on the Amazons, 4th ed., pp. 9-15. London, 1875. 



3 Charles Waterton: Wanderings in South America. Explanatory Index, Rev. J. G. Wood, p. 47. 

 London, 1882. 



* The Naturalist in Nicaragua, p. 80. 



