32 



After treatment the respective lots were placed in boxes with 

 tig-ht fitting- glass tops, and at intervals of from two to three days 

 tlie young hoppers, which had hatched out, were counted and 

 killed. 



The various solutions of Carbolic acid were found inefifective in 

 destroying the hopper eggs, and the counting in such test was 

 discontinued after one week. 



The tests were started on Februarv 21st, 1903, and the number 

 of hoppers counted on diiferent dates appear in the table below. 

 The figures for carbolic acid given under date of February 28th, 

 are for the week preceding, only one count having been made : 



00000 

 o o o o T 

 00000 



K" o 



000000 



O O O O O I 



000000 



Another series of experiments was conducted with similar lots 

 of cane, to note the elTect of fumigating sections of stalk with Hy- 

 drocyanic acid gas for varying lengths of time, one ounce of Cy- 

 anide of Potassium being employed for 27 cu. ft. of space. It was 

 also determined to merely dip other sections in Corrosive Subli- 

 mate and compare the results with those obtained where the cane 

 was soaked in such solutions. 



