INSECTICIDES. 481 



branch, which, July 25, was resprayed on account of rain: 

 Five of the ten i^upated, one of which emerged. Foliage 

 badly burned. 



No. 6. — July 10, 1893. A branch of oak was sprayed 

 with arsenate of zinc, in the proportion of 3 lbs. to 150 

 gal. of water, and ten fifth-niolt caterpillars placed upon it. 

 Five of these began pupating, but none emerged. Foliage 

 badly burned. 



No. 7. — Jnly 6, 1893. A branch of oak was sprayed 

 with arsenate of zinc, in the proportion of G 11)S. to 150 gal. 

 of water, and ten tifth-molt caterpillars placed upon it. At 

 the end of two weeks all were dead. Foliage ])urned. 



No. 8. — July 6, 1893. A branch of oak was sprayed 

 with arsenate of zinc, in the proportion of 6 lbs. to 150 gal. 

 of water, and ten fifth-molt caterpillars placed upon it. All 

 but one died within a week, and this one died eleven days 

 after the branch was sprayed. Foliage burned. 



Arsenic. 



No. 1. — July 12, 1893. A branch of oak was sprayed 

 with arsenic, in the proportion of 6 lbs. to 150 gal. of water, 

 and ten caterpillars of the fifth molt placed upon it. July 

 19, the branch was resprayed, on account of rain, and again 

 on the 25th. Of the ten caterpillars, six began pupating, 

 one of which pupated and emerged. Foliage badly burned. 



No. 2. — July 12, 1893. A branch of hop-hornbeam was 

 sprayed with arsenic, in the proportion of 6 lbs. to 150 gal. 

 of water, and ten caterpillars of the fifth molt placed upon 

 it. July 19, the foliage was so badly burned that the cater- 

 pillars were transferred to a freshly sprayed branch of oak. 

 Only one began pupating, and this one did not emerge. 

 Foliage of hop-hornbeam very badly burned, while that of 

 the oak was in good condition. 



" Chloro-naptholeum." 

 No. 1. — May 15, 1894. Ten caterpillars, before the 

 first molt, were placed on a leaf which had been sprayed 

 with chloro-naptholeum. At the end of seven days, all the 

 caterpillars but one were alive and in good condition. 



