408 THE GYPSY MOTH. 



Benzine. January 22. A small amount of benzine was 

 poured upon an egg-cluster and then allowed to evaporate. 

 Apparently the eggs were not affected, for by March 24, 

 about three-tenths of them had hatched. Nearly five-tenths 

 of the caterpillars died while hatching. 



Bromine. January 19. Five egg-clusters were placed 

 in a box and a small amount of liquid bromine turned on 

 them. At the end of fifteen minutes they were entirely 

 destroyed. 



Bromine Vapor. January 19. Five egg-clusters were 

 submitted to the action of bromine vapor in a closed box 

 for ten minutes. At the end of this time the eggs were 

 destroyed. Another experiment on the same date, in which 

 the eggs were exposed for fifteen minutes, gave similar re- 

 sults. From egg-clusters treated, on the same date, with 

 bromine vapors for a period of ten minutes, the vapor not 

 being closely confined, a few caterpillars hatched. Four 

 caterpillars hatched from other egg-masses treated in the 

 same manner. 



Chlorine. January 15. One egg-cluster was submitted 

 for five minutes to the action of chlorine gas, made by add- 

 ing ten parts (by weight) of hydrochloric acid to eight 

 parts of black oxide of manganese, and then applying a 

 strong heat to the mixture. The egg-cluster was bleached 

 and the eggs destroyed. Four other experiments, in which 

 egg-clusters were exposed to the action of chlorine for 

 seven, ten, fifteen and thirty minutes respectively, gave 

 similar results. March 12. Some chloride of lime was put 

 into a flask and sulphuric acid added to it. The chlorine 

 was then conducted into a bottle containing gypsy moth 

 egg-clusters. It entirely destroyed the eggs, with but one 

 exception. January 19. Five egg-clusters were treated 

 with chlorine under a hood made of oil-cloth stretched over 

 a frame, but, as the oil-cloth was not large enough to en- 

 tirely cover it, a part of the gas escaped. One egg-cluster 

 was bleached, while the others were apparently not affected ; 

 about one-third of the eggs hatched the following spring. 



Carbon Bi-sulphide. January 19. Five egg-clusters 

 were submitted to the action of hot vapors of carbon bi-sul- 



