October, '09] 



JOURNAL OP ECONOMIC ENTOMOLOGY 



327 



heavily overrun with them and they proved themselves intolerable 

 nuisances during the ensuing summer. 



The experiment was repeated on the same premises (a city lot 

 about 40 by 100 feet) in the fall of 1908, but the colony was destroyed 

 with bisulphide during February, 1909. The difference in the in- 

 festation of the premises this season, as compared to last, is remarkable. 



Fig. 5. — "Winter trap" for tlie destruction of Argentine ant colonies. The 

 heat of tlie decaying vegetation attracts the colonies to the box, where they 

 are destroj^ed by fumigation with bisulphide of carbon. 



Up to the present writing (July 25th) their presence has hardly 

 been noticed, many days elapsing at a time without a single ant being" 

 seen inside the residence. At the present time, however, the place 

 is again being occupied by colonies working their way into the prem- 

 ises from adjoining lots, where no steps were taken for their destruc- 

 tion. 



So effective has this winter trapping appeared to be that we fully 

 believe that if it were carried out uniformly, by the residents of sev- 

 eral or more contiguous city blocks acting in cooperation, few if any 

 other measures would be necessary to hold the pest' in reasonable 

 check. 



Destruction of Colonies in Summer 



Much can be accomplished by destruction of colonies during the 

 summer months, but owing to the relatively small size of the colonies 

 and their occurrence in every conceivable situation,^ steady and per- 



*Following are some of the situations in which colonies of the Argentine ants 



