INSECTICIDES. 459 



Check experiment : three pupated the fourth and two the 

 fifth day ; one died and one pupated the seventh day ; one 

 died the eighth day ; and two were living at the close of the 

 experiment. 



No. 59 (field experiment). — July 9, 1894. Ten cater- 

 pillars, of the fifth molt, w^ere placed on willow branches 

 which had been sprayed w^ith arsenate of load, in the pro- 

 portion of IJ lbs. to 150 gal. of water. One died the fifth 

 day ; one pupated the eleventh and one the twelfth day, one 

 died the fourteenth day ; one pupated the fifteenth day, one 

 died the sixteenth day ; one pupated the eighteenth, one the 

 twentieth, one the twenty-first and one the twenty-fourth day. 



No. 60 (field experiment). — June 24, 1893. A branch 

 of apple tree was sprayed with arsenate of lead, in the pro- 

 portion of li lbs. to 150 gal. of water, and ten fifth-molt 

 caterpillars placed upon it. July 10, one caterpillar having 

 pupated and been removed, those remaining were transferred 

 to a freshly sprayed apple branch. Only four of the ten 

 which pupated emerged. Foliage uninjured. 



2 lbs. Arsenate of Lead to 150 gal. Water. 



No. 61. — March 7, 1894. Ten caterpillars, three days 

 old, were placed on lettuce leaves which had been treated 

 with arsenate of lead, in the proportion of 2 lbs. to 150 gal. 

 of water. One died the first, four the fourth, two the fifth 

 and two the sixth day ; and one was lost. 



No. 62. — May 9, 1894. Ten caterpillars, six days old, 

 were placed on lettuce leaves which had been treated with 

 arsenate of lead, in the proportion of 2 lbs. to 150 gal. of 

 water. On the fifth day five were dead ; two died the sixth 

 and three the seventh day. 



Check experiment : none dead. 



No. 63. —May 28, 1894. Ten caterpillars, of the first 

 molt, were placed on lettuce leaves which had been treated 

 with arsenate of lead, in the proportion of 2 lbs. to 150 gal. 

 of water. On the fourth day two died; on the fifth, three; 

 on the sixth, two ; on the seventh, one ; on the eighth, one ; 

 and on the eleventh, one. 



Check experiment : one died the sixth day. 



No. 64, — June 10, 1894. Ten caterpillars, of the second 



