GEOLOGIC WORK OF ANTS—BRANNER. 305 
enough for them to carry, require to be guarded with constant caro. 
I have known entire bagfuls of farinha de mandioca to be carried 
away by them. In short, the inhabitants have to be constantly on 
their guard against the ants, both indoors and out of doors, to say 
nothing of the mere inconvenience of their presence. Nor can their 
importance be regarded as whimsical in any sense; indeed, I am 
convinced that they are social, and even national, factors that are 
not to be ignored. 
Nothing in the way of a biologic or systematic study of tropical ants 
is attempted in the present paper. However valuable such a study 
might be, it is the number of individuals, rather than the number of 
species, that concerns the geologists, though it is recognized, of course, 
that some species are much more active agents than others. We need 
concern ourselves with only two large orders—the true ants belonging 
to the Hymenoptera, and the termites, or so-called white ants, neurop- 
teroid insects which belong to the /soptera, and are known all over Brazil 
by the popular Indian name of “‘cupim.” And nothing is attempted 
in the way of a study of the architecture of their nests and under- 
ground passages, save in so far as such details will give a better idea 
of the geologic bearing of these matters. 
In studying the work of ants in the Tropics one is constantly 
reminded of Mr. Darwin’s studies of the work of earthworms. Mr. 
Darwin was able to give the quantitative results of his studies; in 
the case of the ants, unfortunately, quantitative results have not been 
possible. The time occupied by them in doing a given amount of 
work varies so much that quantitative observations, in order to have 
any value, would have to be carried on upon many colonies and for a 
long period of time. The results given at page 316 are an attempt at 
quantitative determination, but it will be observed that it is not 
known how many individuals took part in the work or how long they 
were at it. 
To illustrate this article especial pains have been taken to get as 
many photographs and sketches as possible of the above-ground 
structures of ants and termites, and the accompanying illustrations 
have been carefully made from photographs, most of them taken in 
Brazil. It seemed better to have the drawings made rather than to 
use the original photographs, in spite of the evident suspicion of 
exaggeration or alteration, whether intentional or accidental, to 
which all drawings areopen. This redrawing was the more necessary 
because the photographs were taken hastily and under many unfavor- 
able circumstances, and they are therefore often not good, or they are 
not available for reproduction as photographs. Abundant illustra- 
tions are given because it is felt that they are the most trustworthy 
witnesses one can put in evidence regarding the subject. 
38734°—sm 1911——20 
