INJURIOUS INSECTS OF 1904. 25 



in this instance. The gas generated by this Hquid, when mixed- 

 with air, is highly explosive, and no lighted match or lamp, or 

 lighted cigar or pipe should be brought near it. As it is definitely 

 known just how much of this liquid is required to create a "death 

 atmosphere," the cubical contents of this room, or better, house, 

 should be accurately determined. From experiments tried with 

 this gas by the writer, he would suggest one part of liquid for 

 every one thousand parts of atmosphere. To determine, if pos- 

 sib.le, whether this strength of gas would penetrate to the center 

 of the bale in killing quantity, the Entomologist inclosed "worms," 

 pupae, and moths in vials loosely stoppered with cotton. These 

 vials were placed in a flour sack, which was tightly rolled up. This 

 bundle was placed in a second flour sack, which in turn was tightly 

 rolled, and the package placed in a burlap sack and rolled again. 

 This compact bundle with the worms in the very center was then 

 exposed for three days, in a tight iron box, to fumes of carbon bi- 

 sulphide, one part of the liquid to 1,000 parts of atmosphere. This 

 killed every "worm," pupa and moth. The fumigation house or 

 room must be absolutely tight to retain the gas. The liquid should be 

 placed in shallow trays, and the room closed for at least three days 

 if the sacks are left in the bale. A longer time than that, under 

 such conditions, would be highly desirable. If the worm cannot 

 be reached in the bale by fumigation for three or five days with the 

 above strength, millers should be willing to open up the bales. 

 This involves extra handling, and means added expense, but might 

 be an imperative necessity, for zcork not thoroughly done in this con- 

 nection represents time and money thrown az^'ay. After fumigation 

 the house or room should be thoroughly aired before allowing a 

 light of any kind inside. 



The gas from bisulphide of carbon will sink through a mass of 

 wheat in a large bin, and also through a chestful of woolen cloth- 

 ing, if in each case the liquid is placed in shallow dishes on top of 

 the wheat, or clothing. It is probable, therefore, that it will pene- 

 trate a loose bale of sacks. Possibly heat alone might be profitably 

 used in this connection. 



