304 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1911. 



In the United States we have very little evidence of ants making 

 either underground passageways or mounds of sufficient size or 

 extent to have attracted much attention. Indeed, it seems to be 

 generally conceded by entomologists that the ants of the northern 

 part of North America are not as enterprising as those farther south, 

 or even as those of Europe. Forel seems to have found the structures 

 of our North American ants so insignificant that he avoided speaking 

 of them as having mounds at all. Certainly the little ant hills we 

 have seen in most parts of the United States are too insignificant to 

 attract the attention of geologists. In the South and Southwest 

 they are somewhat more conspicuous, and in the semiarid portions of 

 western Texas and in Arizona, New Mexico, and parts of California 

 they have attracted not a little attention. 



The western halves of Oklahoma, Kansas, and Nebraska and the 

 eastern portion of Colorado are inhabited by mound-building prairie 

 ants that are sufficiently abundant and sufficiently pugnacious to 

 have attracted the attention of farmers and entomologists, if not 

 geologists. 1 



In the Western States generally ants are more abundant than they 

 are in the East, but a writer on the ant hills of southwestern Wisconsin 

 says that in that part of the country he knows at least a hundred 

 so-called ant hills within a radius of 5 miles, and he appears to regard 

 this number as quite striking. Their mounds r he says, are as much 

 as 75 centimeters in diameter and 40 centimeters in height. 2 These 

 cases are mentioned simply for the purpose of contrasting the size 

 and number of ant hills in a region that seems to be regarded as 

 pretty thickly inhabited with some of the typical localities in the 

 tropical portions of South America. 



Furthermore, in the tropical parts of America ants are not the 

 simple and easily ignored insects with which we are acquainted in the 

 temperate zones of the earth. Save in the cities, they are almost 

 omnipresent. To the housekeeper they are not only never-sleeping 

 pests, but they are bold and defiant robbers or sneak thieves, as cir- 

 cumstances require or permit. To the planters they are veritable 

 plagues ; they destroy the growing crops as completely as if they had 

 been burned over. They do not wipe out a field of grain in a few 

 hours as completely as do the locust swarms of Argentina, and then 

 disappear, but they stay with their work right alongside of the crops, 

 and with time they destroy them no less certainly. Unlike the 

 locusts, they do not come and depart, but they stay right in one cir- 

 cumscribed area all their lives. Farinha de mandioca, the meal pre- 

 pared from the cassava plant, or grain of any kind and of a size small 



1 T. J. Headlee and George A. Dean: The mound-building prairie ant (Pogonomyrmex occidentalis Cresson). 

 Bull 154, Kansas Agricultural Experiment Station. Manhattan, 1908. 

 s Hermann Muckermann: Psyche, vol. 9, pp. 355-360. Boston, 1902. 



