460 THE GYPSY MOTH. 



molt, were placed on elm leaves which had been sprayed 

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

 of water. One died the second, three the fourth, three the 

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



Check experiment : none dead. 



No. 65. 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 2 Ibs. to 150 gal. 

 of water. Four died the third, three the fourth, two the 

 sixth and one the seventh day. 



Check experiment: one lost the seventh and one the 

 eighth day. 



No. 66. June 29, 1894. Ten caterpillars, of the fourth 

 molt, were placed on elm leaves which had been sprayed 

 with arsenate of lead, in the proportion of 2 Ibs. t6 150 gal. 

 of water. Two died the fourth, four the fifth, two the sixth 

 and two the seventh day. 



Check experiment : one died and two pupated the second 

 day ; two died the third day, two the fourth and three the 

 fifth day. 



No. 67 (field experiment). June 21, 1893. A branch 

 of hop-hornbeam was sprayed with arsenate of lead, in the 

 proportion of 2 Ibs. to 150 gal. of water, and ten fourth- 

 molt caterpillars placed upon it. Four of these caterpillars 

 began to pupate, and, as the food gave out, those remaining 

 were transferred to a branch which had not been sprayed, 

 two more pupating after their removal. The other four cater- 

 pillars died from the effects of the poison. Foliage uninjured. 



No. 68 (field experiment). June 24, 1893. A branch 

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

 portion of 2 Ibs. to 150 gal. of water, and eight fourth-molt 

 caterpillars placed upon it. On account of the rain, the 

 branch was resprayed twice. One caterpillar pupated, and 

 from the pupa a male moth emerged. The rest were all 

 dead by the 9th of August. Foliage uninjured. 



No. 69 (field experiment). June 24, 1893. A branch 

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

 portion of 2 Ibs. to 150 gal. of water, and nine fourth-molt 

 caterpillars placed upon it. Five of the caterpillars died 

 before pupating, and, of the four that pupated, three emerged. 



