86 THE ARGENTINE ANT. 



of the same room and "rediscovered" by the workers they seemed not 

 to recognize its dangerous nature and would take it as before. After 

 a few expeiiences of this kind the colony would move away from the 

 %dcinity. Only in rare instances were these migrations actually -wit- 

 nessed, as they seemed usually to take place during the night. A 

 solution containing more than one-fourth of 1 per cent of arsenic did 

 not give as good results for, in such cases, many of the workers cUed 

 wliile sipping up the poison or on their way to the colony. Thus the 

 poisonous nature of the substance was more quickly detected by the 

 ants and work on it was stopped proportionately sooner. In all cases 

 the ants removed the dead and dying from along their trails and from 

 the vicinity of the poisoned mixture. 



A number of experiments were made to determine whether or not 

 the ants could distinguish between poisoned and nonpoisoned foodsj 

 with the result that they evidently could not do so; tliis perhaps being 

 the reason that they moved their colonies away from the vicinity. 

 One of these experiments was as follows: 



On July 9 a fruit jar containing honey was placed on the floor of a 

 small shed, where the ants had been very abundant for weeks. By 

 the following day all hone}^ had been removed by the workers and more 

 was placed in the jar. Between the 9th and the 12th the jar was 

 replenished several times, the ants during tliis time carrj^ng away 

 more than a half pint of honey. At noon on July 12 a small glass 

 vessel containing a mixture composed of one-half of 1 per cent of 

 arsenic and 20 per cent of sugar was placed about 3 inches from the 

 honey jar. The ants commenced taking tliis solution at once, and 

 in the course of five minutes the vessel was black with them. At 4 

 p. m. on the same day they were still worlang with, undiminished 

 vigor on both the honey and the poisoned solution. At 8 a. m. on 

 July 13 there were only about one-fourth as many ants ^asiting the 

 jars as on the pre\dous day. They were still worldng on both the 

 honey and the solution and many dead ants lay about. At noon of 

 the same day very few were visiting the vessels, but many were 

 engaged in carrpng away the dead bodies of their erstwhile sisters. 

 A few were still taking the arsenic solution, but it was e^adent that the 

 ants did not know wliich of the food supplies was destropng them. 

 At 2 p. m. on July 14 only two workers were in the vicmity of the ves- 

 sels and neither of those was feeding. On July 15 all ants, both aUve 

 and dead, were gone, and not a single worker could be found in the 

 building. Plenty of the nonpoisoned honey still remained in the jar. 

 On July 16 and 17, also, no ants were to be found in the shed, even 

 though heavy rainstorms in the meantime drove them indoors in 

 many other buildings and decreased their available outdoor food sup- 

 ply. Tliis experiment and many others demonstrated not only the 

 effect of the poison in driving the ants from the vicinity, but also that 



