vs 
326 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1911. 
in order to observe the workers repair them. In every case observed 
the repairs were made by building up a wall or covering of excre- 
ment or something of the kind. At least it is voided from the poste- 
rior part of the body in a plastic condition, and is smoothed down 
on the sides so that the later layers always override the earlier ones 
on both sides of the wall. An examination of their construction, 
however, shows that they are made partly of clay or the earth about 
the nest and partly of woody fiber. These two substances are 
variously mixed in structure, sometimes one being more abundant, 
sometimes the other. An examination of the materials of the out- 
side part of the 'arge and old nests, however, shows that this part 
of the nest at least contains fragments of quartz, sand grains, and 
such like rock fragments that could not possibly have passed through 
the bodies of the insects. The structure of some of the nest walls 
suggests that these walls are constructed partly of earth and rock 
fragments brought up from beneath the ground and built into the 
nests by cementing them together with excrement or some other 
adhesive substance. 
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 sub- 
stanee 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 or6 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 unfortu- 
nately 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 arule, the mounds are rudely domed, rounded or conical, and the 
method of adding to the outside gives them a bumpy, lumpy appear- 
ance, 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 dif- 
ferent 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. 
