INJURIOUS INSECTS OF 1904. • 35 



does not evaporate quickly enough to produce the death atmosphere 

 required." This firm used three hundred soup plates half filled 

 with bisulphide and distributed throughout the mill, besides satur- 

 ating balls of cotton with the same and placing them in all reels 

 and purifiers. The mill was left from Saturday night to Monday 

 morning, and although thousands were found dead, many thousands 

 more appeared from cracks and corners after a few days. 



Sulphur: The burning of sulphur not practical, besides injuring 

 the flour in sacks in the mills. 



Steam: Not practical, requiring too elaborate preparation, and 

 too frequent application ; seriously injuring grain or flour, and rust- 

 ing machinery. 



Kerosene: Good for washing walls, machinery, floors, etc., where 

 it cannot injure flour or grain. See reference to kerosene on page 

 32. 



Solution of Soda and U^atcr: Used strong for washing inside 

 of machines. 



Buhach, or Persian Insect Pozvdcr: Has been burned in a mill 

 with only partial success, and expensive. 



Ammonia: Not successful. 



Hydrocyanic Acid Gas: Coming quite generally into use. Placed 

 in this list on account of danger of application unless in the hands 

 of experienced parties. Deadly to all animal life. Prof. W. G, 

 Johnson, author of "Fumigation Methods," says he has freed a 

 number of mills of the Mediterranean Flour Moth by the use of 

 this gas. 



Corrosive Sublimate: Not desirable. 



Lime: Whitewash to which a little glue has been added excel- 

 lent for ceilings and walls ; the tendency to rub off can be stopped, 

 it is said, by adding a handful of common salt, and a half teacupful 

 of lard to each gallon of wash, which should be thoroughly strained 

 before beixig used. 



Sidphuric Acid: Not recommended. 



Tobacco: Not particularly effective, either as smoke or infusion. 



Flour Paste: Compound of flour, water and vinegar and boiled 

 by steam found to attract insects when paste was at a certain stage 

 of fermentation. Moths fall into paste and perish. Too expensive, 

 and has to be renewed every few days. 



