454 THE GYPSY MOTH. 



the sixth two and on the seventh three ; the remaining one 

 was lost. 



No. 29. 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 f Ib. to 150 gal. of 

 water. All lived through the experiment. 



Check experiment : none dead. 



No. 30. 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 | Ib. to 150 gal. 

 of water. One died the eighth and three the tenth day ; 

 those remaining lived through the experiment. 



Check experiment : none dead. 



No. 31. 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 | Ib. to 150 gal. 

 of water. Two died the fifth, one the ninth, one the 

 eleventh, two the thirteenth and four the eighteenth day. 



Check experiment : none dead. 



No. 32. 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 f Ib. to 150 gal. 

 of water. One died the third, one the seventh and one the 

 ninth day ; one pupated the tenth day ; one died and one 

 pupated the eleventh day ; and four died the twelfth day. 



Check experiment : one pupated the tenth day and "two 

 died the eleventh day. 



No. 33 (field experiment). June 27, 1893. A branch 

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

 proportion of f Ib. to 150 gal. of water, and nine fourth- 

 molt caterpillars placed upon it. Of these, three died before 

 pupating, and, of the six which pupated, three emerged. 

 Foliage uninjured. 



No. 34 (field experiment). June 27, 1893. A branch 

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

 proportion of | Ib. to 150 gal. of water, and nine fourth- 

 molt caterpillars placed upon it. Of these, seven pupated 

 and emerged, one began pupating but died later, and one 

 died in the larval stage. Foliage uninjured. 



No. 35 (field experiment). June 27, 1893. A branch 



