20 THE ARGENTINE ANT. 



that the queen woukl develop the instinct of attending to and caruig 

 for the eggs, larvi^, and pupfe in succession for several months. 

 Also, the queens are quite helpless and appear to be entu'cly incapa- 

 ble of defending themselves against other insects. The writer has 

 observed a queen ant being captured and bound by a minute spider, 

 considerably smaller in size than her own head, without making 

 the least attempt to struggle. It therefore seems improbable that a 

 defenceless queen could maintain herself in a hostile country for 

 several months without the assistance of workers. 



Furthermore, we have several times kept Argentine ant queens 

 isolated in small nests, sometimes singly and sometimes in groups, 

 but have never yet succeeded in hatching eggs in these nests, or in 

 rearing larvae to the adult stage. 



The fact that ditches of running water have proven sufficient bar- 

 riers to prevent the spread of the species in orange groves appears to 

 disprove the theory that queens returning from the nuptial flight can, 

 without the assistance of workers, establish new colonies. 



DISPERSION BY STREAMS. 



As previously mentioned, driftwood is probably the most important 

 agency in the natural dispersion of the Argentine ant. Along the 

 Mississippi River, below the infested territory, we find a considerable 

 niunber of larger or smaller colonies of the ants, and in places the 

 batture ^ will be infested for miles, with practically no ants inside the 

 levee. This can only be accounted for by ants floating down the 

 river upon driftwood from infested localities. The river banks are 

 covered with logs, more or less rotten, which have stranded during 

 high water. In the infested territory these logs are found full of 

 ants in all stages in enormous numbers. During high water some of 

 these logs drift and lodge alternately, gradually working down the 

 river, and distributing colonies in their wake. 



The writer has several times seen complete colonies of ants on a 

 floating log, unable to escape. All that was required was a little 

 further rise of the water to start them down the river, with their 

 cargoes of ants. 



ARTIFICIAL DISSEMINATION. 



Unquestionably the main distributing agent of the Argentine ant 

 is man liimself, by means of railway trains, boats, and other vehicles 

 which he controls and utilizes in the transportation of freight and 

 commodities of all kinds. The ants must necessarily have been intro- 

 duced to this country by means of ships, and railways have been the 



1 The "batture" is that land lying between the true bank of the river and the levee. The batture is 

 subject to overflow during high water, is ordinarily not cultivated, and is frequently overgrown with wil- 

 lows, 'i'hc liatture is said to bo "outside" the levee, while land protected by the levee from high water is 

 said to be "inside" the levee. 



