462 THE GYPSY MOTH. 



No. 75 (field experiment). — July 7, 1893. A branch 

 of oak was sprayed with arsenate of lead, in the proportion 

 of 2 lbs. to 150 gal. of water, and ten caterpillars, of the fifth 

 molt, placed upon it. On July 22, and also on the 27th, the 

 branch was resprayed on account of rain. In this experi- 

 ment only one caterpillar began pupating, and that one was 

 not able to complete the process. 



No. 76 (field experiment). — July 7, 1893. A branch 

 of oak was sprayed with arsenate of lead, in the proportion 

 of 2 lbs. to 150 gal. of water, and ten fifth-molt caterpillars 

 placed upon it. Three of these began pupating, and one 

 emerged ; but, as this one began to pupate very soon after 

 the poison was applied, it probably did not get any ill efiect 

 from it. Foliage uninjured. 



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



^o^ 77. — 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 3 lbs. to 150 gal. 

 of water. Six died the third, one the fourth and three the 

 sixth day. 



]S|o. 78. — 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 3 lbs. to 150 gal. of 

 water. One died the third, three the fourth, two the fifth, 

 one the sixth and one the seventh day ; the remainder sur- 

 vived. 



Check experiment : none dead. 



No. 79.— 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 3 lbs. to 150 gal. 

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

 one the seventh, three the eighth and one the ninth day. 



Check experiment : one died the sixth day. 



]v^o. 80. — June 10, 1894. Ten caterpillars, of the second 

 molt, were placed on elm leaves which had been sprayed 

 with arsenate of lead, in the proportion of 3 lbs. to 150 gal. 

 of water. One died the fourth, eight the fifth and one the 

 sixth day. 



Check experiment : none dead. 



