410 THE GYPSY MOTH. 



Creosote Oil. — March 14. A small amount of creosote 

 oil was dropped upon five egg-clusters, and, although it did 

 not appear to injure the eggs, none of them hatched. March 

 31. A mixture of creosote oil and pine tar, fifty per cent, 

 of each, was dropped upon some egg-clusters. It pene- 

 trated them at once, and, later, shrivelled the eggs so that 

 none hatched. March 31. Another lot of es^or-clusters was 

 treated in the same manner, and the eggs destroyed. Two 

 experiments with a mixture of creosote oil, fifty per cent., 

 and turpentine, fifty per cent., gave results like those of the 

 preceding experiments. April 7. About eight thousand 

 eggs were saturated with a solution of pine creosote oil, 

 forty-five per cent., turpentine, forty-five per cent., and 

 coal tar, ten per cent. It penetrated the egg-clusters read- 

 ily, and attacked the eggs so that none hatched. 



Coal Tar. — March 5. A mixture of coal tar, thirty per 

 cent. , phenol, forty per cent. , and turpentine, thirty per cent. , 

 was dropped upon ten egg-clusters. It quickly penetrated 

 the eggs, turning them black and softening the shell so that 

 none hatched. Several other experiments with similar tar 

 mixtures gave equally as satisfactory results. 



Eagle Mills Poicder. — March 11. A mixture of Eagle 

 Mills Powder, fifty per cent., and turpentine, fifty per cent., 

 was dropped upon ten egg-clusters, but the mixture was too 

 thick to penetrate. March 11. A solution of Eagle Mills 

 Powder, ten per cent., water, sixty per cent., and alcohol, 

 thirty per cent., was dropped on some egg-clusters, and 

 quickly penetrated to the bottom. This did not injure the 

 eggs, for, by April 12, nearly all had hatched. 



Hijdrocyanic Acid Gas. — January 11. One egg-cluster 

 was submitted to the action of pure concentrated hydro- 

 cyanic gas, in the following apparatus : A Florence flask, 

 containing one-half an ounce of potassium cyanide and aliout 

 twenty culiic centimeters of water, was connected with a 

 wide-mouthed bottle by a tube bent twice at right angles. 

 The bottle also contained an escape tube. An unbroken 

 egg-cluster was placed in the bottle, then sulphuric acid was 

 added to the potassium cyanide in the flask. The hydro- 

 cyanic acid gas passed over into the bottle, driving the air 



