r5 



a considerable percentage of the seeds. To effect improve- 

 ments, it was necessary to prevent the beetles that came to 

 the surface from getting back to the seed for oviposition. 

 The device first thought of was what may be called a paper 

 trap (Fig. 15). A number of semi-circular rings are cut into 

 the paper. The paper is closely adjusted to the surface of 

 the seeds, so that there is no space between them and the 

 paper. The beetles, on emergence, will get through the holes 



Fig. 15 — Paper trap shewing discs cut into it. 



on to the top of the paper, but fail to get back as the semi- 

 circular disc comes in contact against the seeds directly they 

 try to do so and unless the disc is lifted up or drawn a good 

 way, there is no hole sufficiently large for the beetles to pass 

 through. Properly adjusted, the paper trap was absolutely 

 effective. There were drawbacks, however, to an extensive 

 adoption of this device. In the first place, unless the bins 

 are standardised, the size of the paper will have to be varied 

 according to the size of the neck, or, if the bin is not full, to the 

 size required to completely cover the top layer at whatever 

 level this happens to be. Secondly, any careless adjustment 



