33 



The tests may be designated by the following numbers : 



(t) Fumigation with Hydrocyanic Acid (ias for 24 hours. 



(2) " " Hydrocyanic Acid Clas for 12 " 



(3) " " Hydrocyanic Acid Gas for 6 " 



(4) " " H}-drocyanic Acid Gas for 3 " 



(5) Dipping in :{:;«;' Corrosive Sublimate Solution. 



(6) " " 1^' Corrosive Sublimate Solution. 



(7) " " i;^ Corrosive Sublimate Solution. 



(8) ■' "' 2'/ Corrosive Sublimate Solution. 



The canes were put in boxes as in the preceding experiment and 

 tlie insects hatching out were counted from time to time and killed. 

 The numbers of hoppers found on different dates were as follows: 



1 o 



2 o 



3 o 



4 o 



5 o 



6 o 



7 o 



8 o 



The gas was found to be very effective in destroying the eggs, 

 vvhen the cane sections were fumigated for periods of 6 hours and 

 over. C)f the Corrosive Sublimate solutions, 2'^. appeared the 

 most effective, only allowing one insect to appear. 



