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. 
In the Western States generally ants are more abundant than they 
are in the Kast, 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, he says, are as much 
as 75 centimeters in diameter and 40 centimeters in height.? 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 
tropigal 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 
Bull 154, Kansas Agricultural Experiment Station. Manhattan, 1908. 
2 Hermann Muckermann: Psyche, vol. 9, pp. 355-360. Boston, 1902. 
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