THE ARGENTINE ANT: DISTRIBUTION AND CONTROL. 3 
Texarkana, Ark.. Nashville, Tenn., Memphis, Tenn., Augusta, Ga., 
Atlanta, Ga., Charleston, S. C., and Wilmington, N.C. | 
DISPERSION. . 
Under natural conditions the Argentine ant spreads very slowly, and 
this spread is controlled to a large degree by the available food supply. 
Like most other species of ants, the Argentine ant is a very indus- 
trious forager, and a shortage of food tends to hasten its dispersion. 
In October, 1914, a small infestation covering the most of two city 
blocks was found in Memphis, Tenn. The ant numbers could not 
have increased to any appreciable extent during the rather long 
and cold winter of 1914-15, and yet in the early part of the following 
June the infestation was found to involve nearly the whole of five 
blocks. In October, 1915, it developed that the boundaries had not 
been extended, though the ant numbers had greatly increased. The 
food supply must have increased as fast as did the numbers of ants. 
In several instances frequent observations made at points on the 
frontier of the infestation developed the fact that the normal ad- 
vance will average from 300 to 400 feet a year. The abundance of 
native ants has some influence on this advance, since the Argentine 
ant will not tolerate any of the native species, and in sos sence a 
continuous fight is waged all along the frontier. 
Heavy, flooding rains are undoubtedly a factor in the natural dis- 
tribution of this ant, and in the vast region drained by the Mississippi 
River and its tributaries it will be remembered that there are at least 
two dangerous flood seasons and sometimes more, which contribute to 
and accelerate the distribution of this species. Lumber, rotting trees, 
uprooted shrubs, cane growth, fruit, vegetables, and all manner of 
refuse contribute to the mass of matter borne on the crest of flood 
water, and in this the ants seek refuge and are involuntarily trans- 
ported. Nature has endowed this species with a remarkable habit of 
self-preservation from drowning in times of floods, for when rising 
water floods their nests and no other means of escape are presented 
they cluster together and form a compact ball. The immature stages 
form the center of this ball, with the queens and workers as the outer 
portion. As the ball enlarges from the addition of other workers 
which had been struggling alone in the water it gradually revolves. 
It is kept revolving slowly by the outside workers continually striv- 
ing to reach the top of the ball, thus permitting air to reach the 
interior. The writer has had only one opportunity of witnessing the 
formation of a ball of this kind. After a 5-inch rainfall several 
balls, none more than 2 inches in diameter, were observed. According 
to reliable authorities, such balls have been observed on many oc- 
casions, some of them from 6 to 8 inches in diameter. The ants in 
