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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 11 
close relation to the degree of cleanliness about the mill or warehouse or 
store-room. Some of the best mills keep their machinery and floors 
and walls quite free from flour dust by using compressed air for clean¬ 
ing out the cracks and crevices, blowing the dust out where it can be 
easily swept up by brooms. Others make a practice of treating their 
floors at regular intervals with gasoline or kerosene to destroy the lar¬ 
vae and beetles and mites that accumulate in the cracks in all but the 
very best of floors. 
Light is always a great factor in cleanliness and modern mills and 
warehouses are now built so that all parts of the house may be well 
lighted and of course daylight is preferable to any kind of artificial 
light. The claim is sometimes made that insects will not breed in food 
materials that are stood in light places. While it is true that insect 
pests are usually less common in such places, the rule is not a safe 
one in practice, for light does not altogether protect foods from infesta¬ 
tion. Indeed, it seems that, while as a rule these insects prefer to work 
in dark places, they may under certain conditions, probably at breed¬ 
ing time, seek out the light. I have already referred to the swarms of 
rice weevils that had gathered to the light near a window, when the in¬ 
fested material from which they came, was near the middle of a long 
room with light only at the ends. Many other instances might be 
cited where not only the weevils but the moth larvae were found in 
material stored in places where the light was good and strong. 
Given a good, clean, light warehouse or mill, the careful manager 
will watch with unceasing vigilance everything that comes into his 
house. There are certain signs that usually betray the presence of 
insects to the careful observer, even when the food material is packed 
in sacks and boxes, and if there is any reason whatever for believing 
that incoming goods are infested, a careful examination must be made. 
Used sacks are particularly dangerous sources of infestation and should 
always be looked on with suspicion and thoroughly cleaned or fumi¬ 
gated before being admitted to the storeroom. 
But in spite of all our care, infested materials may be carried into 
even the cleanest of places, or the adult insects themselves may fly or 
crawl in. In the same way some of the most important insect pests 
of our farms and orchards have escaped the watchful eye of the quar¬ 
antine officer, and in both instances active control measures soon be¬ 
come necessary. 
In a clean well lighted place, it is usually easy to detect the begin¬ 
nings of an infestation which may be checked before it has spread far, 
but which, if left alone, would soon become of much more importance. 
A lightly infested lot of flour or meal may be sifted or rebolted and put 
in clean sacks with but little loss if the material is in a mill or can be 
