THE ARGENTINE ANT. 19 
MEANS OF DISPERSION. 
NATURAL SPREAD. 
Under strictly natural conditions, the rate of dispersion of Argen- 
tine ants is very slow. Owing to their intensely social habits they 
spread but slowly from a locality until the number present becomes 
excessive for the food supply or unless adverse conditions, such as 
flooding, occur which compel them to seek fresh locations. They 
will then spread in all directions, but will go little farther than is 
necessary to give them sufficient foraging area to insure the food 
required. However, if a large food supply is discovered at a con- 
siderable distance from the colony, a heavy trail of workers will 
soon be formed between the food and the nest, composed of many 
thousands of tiny insects, each busy carrying a load of the coveted 
material back to the nest or going out for another load. Sometimes 
they will construct a new nest in the neighborhood of the food sup- 
ply, and to this they will transport a number of pupa?, larvae, and 
eggs from the parent nest. In the course of a day or so this new 
colony will be thoroughly established, with a full supply of queens, 
workers, and immature stages, and will then be capable of supporting 
itself and increasing in numbers without assistance from the parent 
nest. 
Under normal conditions it is likely that the rate of spread does 
not amount to more than a few hundred yards each year. When 
food is plentiful, a well-traveled road or a paved street may restrict 
the spread for a considerable period, but when any much-desired 
food supply, such as the excretions of aphides or scale insects, is to be 
reached, nothing short of running water proves an effective barrier. 
It is possible, but scarcely probable, that the queens may aid the 
natural dispersion by means of flight, but there are several reasons 
why this is doubtful. One of them is that the flight itself is a very 
uncertain event, as during the five years that these ants have been 
studied in Louisiana only one general flight has been observed. It 
has been established that the young queens can mate in the nest 
without taking a marriage flight at all, and apparently this is what 
usually takes place. Even should a fertilized winged queen fly or 
be transported by the wind to any considerable distance from the 
ant-infested territory, it is very doubtful whether any eggs she might 
lay would ever hatch. The queen has never been observed assisting 
in the slightest degree with the rearing of the young in the nest, nor 
have we succeeded in getting eggs to hatch when they were not 
cared for by the workers. As the workers are never winged, the 
queen would necessarily be alone, and it would be very unlikely 
