246 HOUSEHOLD INSECTS 



four broods a season. In the South and in California 

 there may be more. If infested material is stored in a 

 warm pantry or kitchen, the insects will breed all through 

 the year. 



Methods of control. — In mills, where the work of 

 extermination is done on a large scale, fumigation with 

 hydrocyanic acid gas is often resorted to. In the case 

 of a pantry this might also be done. First, however, all 

 of the walls of the storage bin should be gone over with 

 a stiff brush and just as many of the larvae and pupse dis- 

 lodged, swept up, and burned as possible. Then the sacks 

 of infested material should be separated so that the gas 

 will have access to all sides of them. The same care to 

 make the room as tight as possible should be exercised 

 as was advised in the chapter on bedbugs. 



It has been found that freezing will kill all forms of this 

 insect, but the temperature must be zero or below and 

 must continue for four or five days. It is also important 

 to follow this freezing quickly with warm temperatures. 

 It seems that the severe cold followed by high temperatures 

 is more effective than prolonged, even, cold temperatures. 

 Wherever conditions are such that this method can be 

 used the insect may be exterminated. 



Carbon bisulfide may be used if desired to spray the 

 infested sacks and masses of flour or other cereal and to 

 fumigate a storage bin or pantry. If used to fumigate, 

 the room should be made tight, and two pounds of the 

 liquid to each 1000 cubic feet of space should be used. 

 The gas from carbon bisulfide is inflammable and no 

 lights of any kind should be brought near the room which 

 is being fumigated. 



Probably the most economical way to follow in a private 



