482 J. C. BRANNER GEOLOGIC WORK OF ANTS 



The outer parts of the nests, when they stand on the ground, are, so far 

 as my observations go, always made of earth cemented in a thick, hard 

 wall. In the inner portions of the nest the partitions are thinner, and 

 though they are made largely of an easy-spreading clay, they are often 

 made partly, or at least overspread, with a dark, friable substance that 

 has the appearance of being masticated wood, leaves, or other organic 

 matter. 



The openings through the mass of the nests are pretty uniform in 

 size, being from 3 to 10 millimeters in diameter and averaging close to 



5 or 6 millimeters. The openings within the nests sometimes have the 

 appearance of being arranged in rude tiers; sometimes they are appar- 

 ently haphazard labyrinths. 



The external forms of the nests vary considerably, but unfortunately 

 I do not know whether this variation is due to difference in the species 

 of termites, to difference in the nature of the ground, or to other causes. 



As a rule the mounds are rudely domed, rounded or conical, and the 

 method of adding to the outside gives them a bumpy, lumpy appearance, 

 so that, as Burmeister suggests, they resemble gigantic Irish potatoes. 

 In some localities they are mostly tall and slender. Most of the tall, 

 slender forms observed have been in wet ground or on ground that is 

 sometimes overflowed. For this reason it is inferred that these forms 

 are due to the presence of water rather than to a different species of 

 termites. In size they also vary greatly. I have seen them as much as 



6 meters high and 8 meters in circumference, but these very large ones 

 are exceptional. 



In southern Minas, south of Barbacena, Dr. E. Walsh notes mounds 

 of the white ants 10 or 12 feet high : "I rode close by several which were 

 considerably higher than my head on horseback and 9 or 10 feet in cir- 

 cumference."*® 



Charles J. Dulley cells me that in the vicinity of Caximbu, in southern 

 Minas, he has seen white ants' nests 4 meters high and nearly 2 meters 

 in diameter at the base. Mr. H. E. Williams, assistant on the Geological 

 Survey of Brazil, says that in the vicinity of Taubate, in Sao Paulo, they 

 are often 2.4 meters high, while about the city of Sao Paulo they usually 

 are 1 meter and less in height. 



Gardner says that many of the level tablelands of the interior of 

 Piauhy, where the soil is red clay, the mounds of white ants are abun- 

 dant and often 6 or 8 feet high.*'' 



*8 Rev, R. Walsh : Notices of Brazil in 1828 and 1829, vol. ii, p. 50. Boston, 1831. 

 *» George Gardner : Travels in the interior of Brazil, p. 280. London, 1846. 



