HISTORY AND DISTRIBUTION, 15 



occupied territory, as illustrated by the infestation at New Orleans, 

 to areas where the ants -are so scarce that one not accustomed to their 

 habits would fail to discover them. The latter condition prevails at 

 l)resent in ]\Iobile, Ala, The only places remote from railroads 

 where they have been discovered are upon the banks of the Missis- 

 sip})i River below infested localities. Their presence in such loca- 

 tions is easily accounted for by supposing that they have been carried 

 thither on driftwood, which, carrying numbers of ants from infested 

 phices farther up the stream, has become stranded on the river banks, 

 thus establishmg new foci. In all other cases the infested territory 

 is on a railroad, and usually on a main line running out from New 

 Orleans. For example, nearly every town along the Southern Pa- 

 cific Railway between New Orleans and Lake Charles is infested, and 

 the same statement applies to points on the Louisville & Nashville 

 Railroad between New Orleans and Mobile. 



OCCURRENCE AND DISTRIBUTION IN CALIFORNIA. 



The first specimens of the Ai'gentine ant observed in California 

 were collected in 1907 by Mr, J, Chester Bradley, at that time an 

 assistant in the entomological department of the University of Cal- 

 ifornia. The identity of the specimens was not established untU 

 1908, when Dr. W. M. Wheeler found them to be Iridomyrmex humilis 

 Mayr. 



As soon as the dangerous nature of the pest was known. Prof. C. W. 

 Woodworth took steps to make a study of the species along the same 

 lines as was being conducted in Louisiana at that time, and as a result 

 of his prelimmary work he issued a warning circular ^ to the j^ublic 

 in August, 1908. In tliis circular he gave a Iprief outline of the 

 habits of the ant and reported the following localities as infested: 

 In the central portion of the State, East Oaldand, Alameda,\San 

 Francisco, San Jose, Cupertino, and a point near CampbeU; in the 

 southern part of the State, Los Angeles, Azusa, and Upland. 



In 1910 Prof. Woodworth ])ublished another small bulletin ^ giving 

 the results of his two years' study of the insect. In this paper the 

 infested territory was more clearly defined, and was estimated as 

 consisting of a total area of 5,000 acres. About twice the area was 

 reported infested in 1910 as in 1908, owing to the discovery of a few 

 new colonies and the natural spread of the ones first discovered. 



Our information as to the extent of the infested area in California 

 (see fig. 2) has been obtained principally through the kind offices of 

 Mi\ Ralph Benton, of the California Agricultural Experiment Station, 

 and ;Mi-. P. E. Smith, of Santa Paula, Cal., as well as from the pubU- 



1 The Argentine ant in California. Cal. Exp. Sta. Cir. 38, Berkeley, Cal., August, 1908. 



2 The control of the Argentine ant. Cal. Exp. Sta. Bui. 207, Berkeley, Cal., October, 1910. 



