32 INJURIOUS INSECTS OF 1904. 



An exposure of 6>4 days to a temperature of 3 to 5 degrees 

 above zero kills eggs, larva;, pupae and moths. In view, however, 

 of certain experiments in mills where there are many protected 

 corners and cracks, and where eggs, worms and pupae are found 

 in matted flour, any attempt to use the "freezing process" in a mill 

 calls for from six to eight days' exposure to a temperature as low 

 as it is posible to obtain, certainly as low as zero in every part of 

 the mill, to be perfectly successful. As intimated above, if alter- 

 nate freezing and thawing, followed immediately by a second freez- 

 ing, can be secured, the best results will be obtained. 



Spraying with Bisulphide of Carbon. 



This method, which has been very successfully practiced, con- 

 sists in forcing the liquid by a .syringe made for the purpose into 

 all the machinery infested, inside of spouts, etc. Parts of the mill 

 or fittings which do not come in contact with grain or products 

 made from same can be well treated with kerosene, squirting it 

 into cracks between joists, and into cracks between joists and iron 

 braces, into cracks about windows, along baseboards, and into 

 cracks in floor, walls and ceilings. It is evident that this must be 

 done most thoroughly to reach all eggs or worms concealed in such 

 places. Fig. 14 represents a syringe used for spraying the bisul- 

 phide or kerosene. It may be made of iron pipe, of brass, or of tin. 

 It is eighteen inches long, two inches in diameter, and will hold, 

 at those measurements, about one quart. The rose is detachable, 

 unscrewing from the barrel, and it (the rose) is filled on the end 

 with many very small holes, as small as the finest needle, in order 

 that the liquid may not be wasted. In filling the syringe the rose 

 can be unscrewed and the end of the syringe immersed in the can 

 holding the bisulphide, or, and this is much better, a little hole cov- 

 ered by a screw cap, not shown in the illustration, may be made on 

 the side of the rose and the liquid drawn in through that. This is by 

 far the best plan, for when the rose is unscrewed and the liquid 

 drawn into the syringe it necessitates the holding of the filled barrel 

 upright in order to screw on the rose, under which circumstances 

 the liquid will run out below, near the handle, unless the piston rod 

 fits very snugly. 



