THE ARGENTINE ANT. 



INTRODUCTION. 



The Argentine ant {Iriclomyrmex liumilis Mayr), which is made the 

 subject of the present paper, is the first among the Formicidae to attain 

 the front rank among injurious insects in the United States. In its 

 field the Argentine ant is not excelled in destructiveness by even the 

 gipsy moth, the boll weevil, or the San Jose scale. Though this ant 

 is limited as yet to comparatively small areas, the observations and 

 experience of the authors fully convince them that future years will 

 see this insect steadily invading new territory and forcing its depre- 

 dations upon the inhabitants of all southern California and most of 

 the Gulf States. 



The present paper aims to present, in as concise a manner as possi- 

 ble, the principal results of five years of almost constant observa- 

 tion and experiment by the senior author at Baton Rouge, La., and in 

 the orange-growing section of the same State, together with observa- 

 tions made by the junior author at New Orleans in connection with 

 his investigations of sugar-cane insects. 



The junior author has prepared in their entirety the portions deal- 

 ing with the ''Area of ultimate infestation," and the " Relation of the 

 ant to Coccidfe and Aphididae," and to him is also to be credited the 

 important discovery that mating of the queens may occur withm 

 the formicary or nest of the colony. The remainder of the paper, 

 excejit where otherwise noted, is compiled from the notes and records 

 of the senior author. 



In the tedious work which accompanied the determination of the 

 ant's life history, from 1907 to 1910, much assistance was rendered 

 by the young men associated with the senior author in the work of 

 the Louisiana State Crop Pest Commission, particularly Messrs. 

 Harper Dean, A. H. Rosenfeld, G. A. Runner, M. S. Dougherty, 

 G. D. Smith, and R. C. Treherne. 



The writers are under obligations to Dr. W. M. Wheeler, of the 

 Bussey Institution, Harvard University, for permission to use his 

 redescription of Iridomyrmex liumilis and for his kmdness in reviewing 

 the paragraphs upon ''Systematic position" and "Resemblance to 

 other ants." 



Our thanks are also due to Messrs. R. S. Moore and John Meyer, 

 extensive orange growers of Louisiana, for their liberal cooperation 



9 



