- 2 - 



upper section has a small steel rod inserted crosswise near the top to 

 facilitate handling and to assist in removing the device from the tobacco* 

 The lox-Ter end of the spike is pointed so that it will pierce the tobacco 

 satisfactorily. Four holes are drilled through the wall of the spike into 

 each compartment near the bottom but clear of the threaded portion of the 

 adjoining section. With the holes located in the lower half of the com- 

 partment, the gas must penetrate the maximum depth to reach the test insects* 

 A hole x-Jas drilled through the solid section bearing the tip of the spike in 

 order that a small steel rod may be used when necessary to facilitate the 

 unscrewing of the first compartment „ The spike can be made any length or 

 size desired by adding the proper number of sections or by increasing the 

 dimensions of each. In order to minimize the displacement of tobacco, it is 

 desirable to use a spike mth as small a diameter as possible for accommo- 

 dating the test insects. Stainless steel proved the most satisfactory metal 

 for use in this apparatus, since it vTOuld enter the tobacco vrith a minimum 

 of displacement and would not corrode after use in the moist stored tobaccOo 



The cost of the steel spike described herein was about $Uj however, 

 the cost in different localities would depend largely upon labor charges, 



.V : 



Use of Steel Spike 



Test lots of the stages desired of the cigarette beet le( las ioderma 

 serricorne Fab,) and the tobacco moth ( Ephestia e lute 11a Hbn,) are placed 

 in the sections of the spike in perforated gelatin capsules or in small 

 screen cages. The spike is prepared in the laboratory, the sections being 

 assembled as the capsules or small cages are placed inside, A mallet made 

 of hard rubber (which will not batter the top end) is used to drive the 

 spike into the packed tobacco. 



This apparatus has been used extensively during the past year in 

 atmospheric fiainigation experiments and in experiments in partial vacuum. 

 It is satisfactory for use in all grades and types of cured tobacco, and 

 only a small quantity of the tobacco leaf is destroyed by driving the 

 spike into the tobacco. The smooth surface of the steel permits the spike 

 to enter the tobacco with little chance for making openings that vrould 

 permit the gas to reach the insects xd.thout penetrating the tobacco. 



