INSECTICIDES. 471 



second molt, were placed on lettuce leaves which had been 

 sprayed with ar senate of lead, in the proportion of 8 Ibs. to 

 150 gal. of water. Four died the second, two the fourth, 

 one the fifth, one the sixth and two the seventh day. 



Check experiment : none dead. 



No. 129. June 21, 1894. Ten caterpillars, of the third 

 molt, were placed on elm leaves which had been sprayed 

 with arsenate of lead, in the proportion of 8 Ibs. to 150 gal. 

 of water. One died the second, three the third, one the 

 fourth, three the fifth and two the sixth day. 



Check experiment : none dead. 



No. 130. June 29, 1894. Ten caterpillars, of the third 

 molt, were placed on elm leaves, which had been sprayed 

 with arsenate of lead, in the proportion of 8 Ibs. to 150 gal. 

 of water. One died the second, three the third, four the 

 fourth and two the fifth day. 



Check experiment : four pupated the second, one the third 

 and one the fifth day. 



No. 131. July 9, 1894. Ten caterpillars, of the fifth 

 molt, were placed on elm leaves which had been sprayed 

 with arsenate of lead, in the proportion of 8 Ibs. to 150 gal. 

 of water. One pupated the fourth day ; three pupated and 

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

 died the ninth and one the twelfth day. 



Check experiment : one pupated the fourth, fifth, seventh 

 and ninth days. 



No. 132 (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 propor- 

 tion of 8 Ibs. to 150 gal. of water. One died the third and 

 one the fourth day ; one pupated the eighth day ; one died 

 the thirteenth day; three pupated the sixteenth, two the 

 twentieth and one the twenty-second day. 



10 Ibs. Arsenate of Lead to 150 gal. Water. 

 No. 133. 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 10 Ibs. to 150 gal. 

 of water. Five died the second, four the third and one the 

 fourth day. 



