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, were placed on willow branches 

 which had been sprayed with arsenate of lead, in the pro- 

 portion of 1 Ibs. 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 1 Ibs. 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 Ibs. 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 Ibs. 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 Ibs. 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. 



Xo. 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 Ibs. 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. 



Xo. 64. June 10, 1894. Ten caterpillars, of the second 



