June 1895.] INJURIOUS INSECTS AND FUNGI. 



31 



move. This mass often assumes large proportions in mills, 

 impeding the work of the machinery and the action of the 

 frames and dressing silks, and spoiling the flour and grain, 

 for some distance round it. Before the larvse change to pupse 

 they stray from these congeries and choose some quiet cranny 

 or corner wherein to pupate. The chrysalis, as shown without 

 the cocoon in Fig. 3, is .brown, or reddish brown, and is 

 enveloped in a cocoon of silk spun up with grain or flour or 

 branny materials. 



Preventive and. Remedial Measures. 



Cleanliness in mills and stores is essential as a means of pre- 

 venting serious attacks of this insect. All corners, chinks, 

 partitions, and machinery must be cleansed from time to time 

 when opportunities occur. When infestation is noticed it is 

 absolutely imperative to stop work and to thoroughly disinfest 

 every part of the mills. In infested grain and flour stores, a 

 clearance must be made as soon as possible and every part 

 completely disinfested. Sacks and flour bags are fertile sources 

 of infestation. The former, when emptied, should be subjected to 

 heat in oi der to kill the larvae. The latter, unless new or nearly 

 new, may be either exposed to heat or burnt. There is no doubt 

 that much infestation comes in these flour bags imported from 

 many countries, and that the practice of importing flour, which 

 has so enormously increased during the last few years, has tended 

 in an eminent degree to the spread of the Flour Moth throughout 

 the country. Foreign flour comes into grain stores in infested 

 bags, from which the larvae creep into stored corn or into corn 

 in sacks, whicJi is taken into mills for grinding. Bags and sacks 

 must be regarded with great suspicion, especially those coming 

 from Mediterranean ports. 



V/hen a mill is infested, it will be almost impossible to dis- 

 infest it without clearing all flour and grain out of the mill. 

 Sulphur fumes will destroy the insects, but at the same time 

 they injure the flour by the sulphurous acid gas acting upon 

 the gluten of the flour and seriously affecting its baking qualities, 

 as well as rendering it unwholesome. According to the Canadian 

 receipt, 3 lbs. of sulphur with 3 ozs. of saltpetre are required for 

 each 1,000 cubic feet of air space. This is put into metal dishes 

 containing layers of burning cinders, and the fumes are 

 retained within the mill by the tight closure of all doors, 

 windows, and air-holes. In Canada it has been found neces- 

 sary to repeat the sulphuring process in order to eflfectually clear 

 out the pest. 



In destroying the moth in steam flour mills, steam under 

 pressure has been driven through all parts of the machinery, 

 and in some cases over all parts of the building, with con- 

 siderable advantage. In a report on the Flour Moth by 

 Mr. James Fletcher, the Canadian Government entomologist, 



