24 



NEW YORK STATE MUSEUM 



7 in cage 2 and all were dead in cage 3. April 2 all were alive 

 in cage i, 8 in cage 2 and 3 in cage 3. April 5, 4 were alive in 

 cage I ; 2 in cage 2 and i in cage 3. 



Experiment 15, April i, the exposure being i hour with 6 

 drams of cyanide. April 2, 5 were alive in cages i and 2 and 

 2 alive in cage 3. April 3, 4 were alive in cages i and 2 and 

 all dead in cage 3. April 5 none were alive in cages i and 3 

 and 3 alive in cage 2. 



Experiment 16, April i, exposure i hour with 8 drams of 

 cyanide. Examination April 2 to 5 showed that all had been 

 killed. 



Experiments with scalecide 



January 20, 1909 





Experiment 



Dilution 



Time 



Number 

 of cater- 

 pillars 



Observations 







1—20 

 1-20 

 1-40 

 1-40 



I min. 



* ': 

 I ' 



10 

 10 

 10 

 10 



Dead, the 21st 



Alive the 21st, s alive the 

 Dead the 21st, 22d 





2 





? . 



22d 



4 





Observations on experiments. Series i apparently shows that 

 nearly dormant free caterpillars can be destroyed by 3 hours 

 fumigation, using i ounce of cyanide to 100 cubic feet of 

 space. A scrutiny of the records also reveals the fact that this 

 amount of cyanide can not be depended upon to kill the insects 

 within their nests. One half this strength, namely i ounce to 

 200 cubic feet of space can not be relied upon to destroy free 

 caterpillars if the fumigation be continued 3 hours though all 

 succumb after a prolonged exposure to the gas such as 21 

 hours. 



Series 2 apparently indicates a most satisfactory method of 

 destroying these pests were it not for the fact that the cater- 

 pillars, prior to the experiments, had been in a warm room of 

 the office for several days and were therefore aroused to nearly 

 normal activity. 



Series 3 apparently gives very satisfactory results if the 

 fumigation be continued even i hour, provided i ounce of cyan- 

 ide be used to each 100 cubic feet of space. Unfortunately, 

 these caterpillars had been exposed to a moderate temperature 

 for at least a day and were hardly in the hibernating condition. 



Series 4 is practically a duplicate of series 3 and apparently 

 gave very satisfactory results. 



