424 THE GYPSY MOTH. 



pillars, of the fifth molt, were placed on willow branches 

 which had been sprayed with Paris green, in the proportion 

 of I lb. to 150 gal. of water. Two died and one pupated 

 the seventh day ; two pupated the fourteenth, two the six- 

 teenth, one the nineteenth, one the twenty-first and one the 

 twenty-third day. 



No. 23 (field experiment). — June 27, 1893. A branch 

 of hop-hornl)eam was sprayed with Paris green, in the pro- 

 portion of I lb. to 150 gal. of water, and ten fifth-molt 

 caterpillars placed upon it. July 8, one died, and the food 

 having given out, those remaining were transferred to an- 

 other branch. Of these, six pupated and emerged, while 

 the other three pupated, but died without emerging. The 

 foliage which was sprayed was so badly burned that the 

 leaves curled and fell off. 



No. 24 (field experiment). — June 27, 1894. A branch 

 of hop-hornbeam was sprayed w^ith Paris green, in the pro- 

 portion of |- lb. to 150 gal. of water, and nine fifth-molt 

 caterpillars placed upon it. July 8, two having died, the 

 remaining caterpillars were transferred to a freshly sprayed 

 oak branch, as the foliage of the hop-hornbeam was burned 

 to a crisp. By the 4th of August all the caterpillars were 

 dead. While the foliage of the hop-hornbeam was badly 

 burned, that of the oak remained in good condition. 



1 lb. Paris Oreen to 150 gal. Water. 



No. 26. — April 26, 1894. Ten caterpillars, three days 

 old, were placed on lettuce leaVes which had been treated 

 with Paris green, in the proportion of 1 lb. to 150 gal. of 

 water. Two died the first, five the third and one the fourth 

 day ; two escaped. 



Check experiment : none dead. 



No. 27. — May 9, 1894. Ten caterpillars, six days old, 

 were placed on lettuce leaves which had been treated with 

 Paris green, in the proportion of 1 lb. to 150 gal. of water. 

 One died the first, two the second, five the third, one the 

 fourth and one the fifth day. 



Check experiment : none dead. 



No. 28.— May 28, 1894. Ten caterpillars, of the first 



