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 | lb. 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 o^ lead, in the proportion of | lb. 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 | lb. 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 | lb. 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 lb. 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 | lb. 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 



