-4 



Table 1.-- Joint toxic action against house flies of certain N- substituted 

 p-ethoxybenzamides and allethrin. Concentration of allethrin 50 mg, 

 and of amides 500 mg. per deciliter unless otherwise indicated. Four 

 replicates. 





Concen- 



Mean 







tration 



mortality- 



Mean 



Adjunct 



at which 



caused by- 



allethrin 





tested 



mixture 



equivalent 





alone 



in 1 day- 





Series 



1/ 



Benzamide, N -butyl -p- etho xy- 

 p-ethoxy-N-ethyl- 

 p-ethoxy-N- methyl 

 p-ethoxy-N-pentyl- 

 p - ethoxy-N -pr opyl- 



Allethrin standard 



Required to demonstrate synergism 



Equation for allethrin standard, Y = 3.381X - 1.427 



Heterogeneity factor, 1 



Mg. per dl. 

 1 



2000 



Percent 



Mg 



. per dl. 



31.4 





55.7 



2000 



37.4 





63.8 



500 



38.9 





65.2 



2000 



37.2 





63.7 



2000 



35.3 





61.5 



200 



90.8 





198 



100 



64.0 





101 



50 



24.3 





48.7 





- 36.4 





62.8 



Series 2 



Benzamide, N - sec - amyl-p- etho xy- 

 N - sec -butyl-p - ethoxy- 

 p - ethoxy-N - diethyl- 

 p-ethoxy-N-isobutyl- 

 p - ethoxy-N - dimethyl - 



Allethrin standard 



1000 



2000 



2000 



2000 



2000 



200 



100 



50 



34.4 

 36.3 

 37.2 

 33.8 

 28.9 

 85.9 

 59.4 

 21.2 



Required to demonstrate synergism 32.4 



Equation for allethrin standard, Y = 3. 12 IX - 1.064 

 Heterogeneity factor, 1 



64.9 

 67.5 

 68.9 

 64.3 

 57.3 



194 



105 

 47.3 

 62.7 



