DOSAGE REQUIEEMENTS. 



43 



Deductions concerning effective dosage. — In formulating a definite 

 table of dosage requirements from the above experiments the most 

 significant results are those in which the amount of cyanid used was 

 sufficient to destroy all but a very small percentage of the insects. 

 Table V gives more complete data concerning the foregoing experi- 

 ments, in which from 95 to 99.9 per cent of the insects were killed; 

 also, for comparison, it gives the dosage called for by tables pre- 

 pared by the author. 



Table V. — Data concerning dosage in those experiments in ivhich 9.5 to 99.9 per cent of 



white flies were destroyed. 



a One of several trees fumigated on night of March 1, 1907. Unsatisfactory results supposed to be due 

 to poor quality of acid. 

 b Exposure, 1 hour and 45 minutes, 

 c Exposure, 2 hours and 50 minutes. 

 d Exposure, 1 hour and 30 minutes, 

 e Exposure, 1 hour and 35 minutes. 

 /Exposure, 1 hour and 55 minutes. 



For purposes of comparison with Table V, the data on the dosage 

 experiments in which all of the insects were believed to have been 

 killed in forty-five-minute exposures are given in Table VI, which, 

 like the jireceding, includes the rate and amount of dosage calculated 

 according: to the dosasie recommendations hereinafter given. 



