GEOLOGIC WORK. OF ANTS — BRANNER. 305 



enough for them to cany, require to be guarded with constant care. 

 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 Hyrnenoptera, and the termites, or so-called white ants, neurop- 

 teroid insects which belong to the Isoptera, 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 are open. 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 



