456 THE GYPSY MOTH. 



of water. One died the second, one the seventh, three the 

 ninth, four the tenth and one the eleventh day. 



Cheek experiment : none dead. 



No. 42. — 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 1 lb. to 150 gal. 

 of water. One died the fifth, two the sixth, three the seventh 

 and four the eighth day. 



Check experiment : one died the seventh and one the 

 eighth day. 



^No. 43. —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 1 lb. to 150 gal. 

 of water. One died the second, one the third, two the 

 fourth and one the fifth, sixth, seventh, eighth, ninth and 

 tenth days. 



Check experiment : one lost and one dead the seventh day. 



No. 44 (field experiment). — June 26, 1893. An apple- 

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

 portion of 1 lb. to 150 gal. of water, and eiglit fourth-molt 

 caterpillars placed upon it. Of these, only one died before 

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

 Foliage uninjured. 



No. 45 (field experiment). — June 26, 1893. A branch 

 of an apple tree was sprayed with arsenate of lead, in the 

 proportion of 1 lb. to 150 gal. of water, and eight fourth- 

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

 pupating, and, of the two which pupated, one emerged. 

 Foliage uninjured. 



No. 46.— July 9, 1894. Ten caterpillars, of the fifth 

 molt, were placed on elm leaves which had been sprayed 

 with arsenate of lead, in the proportion of 1 lb. to 150 gal. 

 of water. One died and one pupated the second day ; one 

 died the third, one the fourth, two the fifth, one the seventh, 

 tenth, eleventh and sixteenth days. 



Check experiment : one pupated the third day ; one died 

 the seventh, eighth, ninth and eleventh days ; two pupated 

 the twelfth day ; one died the thirteenth and one the four- 

 teenth day ; and one was living at the close of the experi- 

 ment. 



