460 THE GYPSY MOTH. 



molt, were placed on elm leaves which had been sprayed 

 with arsenate of lead, in the proportion of 2 lbs 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 lbs. 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 lbs. toUoO 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 lbs. 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 lbs. 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 lbs. 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., 



