536 STATE BOARD OP AGRICULTURE. 



FOREWORD. 



Technical Bulletin No. 11. 



The present bulletin presents the results of an experimental investi- 

 gation of the problem, ''How Do Contact Insecticides Kill Insects?" 

 The study has for the most part, and up to the present, dealt with 

 agents that were believed to produce death by suffocation by stopping 

 the breathing orifices. It is planned to carry on similar study along 

 other promising lines in tl)e hope of discovering facts that may be util- 

 ized in perfecting and rendering more eflScient that great class of con- 

 tact insecticides, which because of low efficiency or high cost are used 

 only when stomach poisons will not apply. 



This work is being done under the Adams Act, and aims to aid in 

 helping in the control of noxious insects. 



R. H. PETTIT. 



