INSECTICIDES. 429 



the seventh day ; one died the thirteenth day ; one died and 

 two pupated the fourteenth day ; two pupated the eighteenth, 

 one the twenty-seventh and one the thirty-first day. 



No. 50 (field experiment). June 26, 1893. An apple- 

 tree branch was sprayed with Paris green, in the proportion 

 of 1 Ibs. to 150 gal. of water, and ten fifth-molt cater- 

 pillars placed upon it. By the 5th of August all had died, 

 none having completed the process of pupation, although 

 two or three had begun. The foliage was badly burned. 



No. 51 (field experiment). June 26, 1893. An apple- 

 tree branch was sprayed with Paris green, in the proportion 

 of 1J Ibs. to 150 gal. of water, and ten fifth-molt cater- 

 pillars placed upon it. Of these caterpillars, six died with- 

 out pupating ; three began to pupate, but died later ; and 

 one pupated and emerged. The foliage was badly burned. 



No. 52 (field experiment). July 14, 1893. An oak 

 branch was sprayed with Paris green, in the proportion of 

 1 Ibs. to 150 gal. of water, and ten fifth-molt caterpillars 

 placed upon it. On July 20, the branch was resprayed on 

 account of rain. Seven of the caterpillars pupated, four 

 of which emerged. Three of these seven began pupating 

 before they had time to eat any of the poisoned food. 

 Foliage badly burned. 



2 Ibs. Paris Green to 150 gal. Water. 



No. 53. April 26, 1894. Ten caterpillars, three days 

 old, were placed on lettuce leaves which had been treated 

 with Paris green, in the proportion of 2 Ibs. to 150 gal. of 

 water. Two died the first, one the second, six the third 

 and one the fourth day. 



Check experiment : none dead. 



No. 54. May 9, 1894. Ten caterpillars, six days old, 

 were placed on lettuce leaves which had been treated with 

 Paris green, in the proportion of 2 Ibs. to 150 gal. of water. 

 One died the second, four the third, one the fifth and four 

 the sixth day. 



Check experiment : none dead. 



No. 55. May 28, 1894. Ten caterpillars, of the first 

 rnolt, were placed on lettuce leaves which had been treated 



