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JOURNAL OF ECONOMIC ENTOMOLOGY 



iVol. 15 



old weevils in which there would be a high rate of mortality. So in 

 the 1921 experiments care was taken to run the experiments in series 

 so that the weevils from a single collection were equally distributed 

 among the day feeding, night feeding and check cages. Also instead of 

 removing the weevils, after their feeding period on the poisoned plant, 

 to caged unpoisoned plants, they were placed in the insectary in gause- 

 covered lantern globes with fresh cotton squares as food. In this way 

 the difficulty from ants carrying away the dead weevils was avoided. 

 The results of the 1921 experiments are given in table II. 



Table II* 



*The blank spaces in the table are due to rainfall ruining this portion of the series of experiments. 



Here the mortality was recorded for a period of 96 hours after the 

 poison had been applied to the plant upon which the weevils were feed- 

 ing. Here the mortality during the 9(3 hours following the application 

 of the poison in the case of the weevils feeding in the absence of dew was 

 85 percent and for the weevils feeding in the presence of dew was 71 

 percent. Here again the death rate was higher among the weevils re- 

 maining on the poisoned plant the shorter period and during the period 

 when they could obtain no moisture. 



It is also of interest to note in this connection that a rather high 

 percent of mortality was obtained from a very short feeding period. 



Cage Test Comparing Conditions where Dew was Excluded with 

 Conditions of Normal Dew Formation 



These tests are the same type as were carried out by Newell and By- 

 num. The writer made a few of these tests to check up his own results 

 obtained from attacking the problem from another point of view. Cages 

 size 4x4x6 feet were used in these tests. The experiments were run 

 in the following series: one cage was poisoned and covered, one was 

 poisoned and left uncovered, one was unpoisoned and covered, and one 

 was unpoisoned and left uncovered. Canvas covers were used for the 

 cages and they were covered only during the period of dew formation 



