- 3 - 



percent, and one at 0.5 percent. The most toxic formamides were the 

 straight-chain monoalkyl-substituted ones above heptyl and the straight- 

 chain dialkyl-substituted compounds above dibutyl. The lower members and 

 the branched members of the series were distinctly less effective. Both 

 the formanilides tested also showed toxicity at the higher concentrations. 



In all the tests N,N-dibutylf ormamide and N,N-dipentylformaraide gave 

 100 percent kill of three insects and one mite at 5 percent concentration, 

 N,N-Diethylformamide also was effective against three insects, but some- 

 what less effective as a miticide. Six compounds were effective against 

 two insects and a mite — N-octylf ormamide , N,N-dioctylformamide, N,N- 

 dtLbenzylf orraamide , o-chloroformanilide, N-ethylf ormanilide , and N-iso- 

 pentylf ormanilide . ~"N,N-Dipropylf ormamide and N-heptylf ormamide gave high 

 kill of two insects. N-tert-Butylf ormamide, N-hexy If ormamide , N-phenethyl- 

 f ormamide, and N-pentylf ormanilide were effective against one insect and 

 one mite. 



Although these preliminary tests show some rough trends in the effect 

 of various substituents in formamides on the toxicity to individual species 

 of insects or mites, it is still evident, as shown in previous work, that 

 there is no consistency in effectiveness against all species. 



