228 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



10 adults, the exposure was made October 7. All material was placed 

 in pill boxes, cigar box lids were placed over the boxes instead of 

 the regular lids. The boxes were placed upon the belt carrier and 

 were run through the rays in eleven minutes. Minimum distance 

 from the target eleven inches, maximum distance about thirty inches. 

 Parallel spark gap 4| inches which was equivalent to about 65,000 

 volts. Amperage If to 2^, averaging slightly over two, milliamperes. 

 Results of examinations: October 15 all exposed eggs and all check 

 eggs had hatched. October 17 treated larvae and check larvae were 

 pupating. Treated larvae presented a normal appearance. October 

 17 only one treated adult alive; also only 1 check adult alive. The 

 treated adults deposited eggs October 9 and 10. Both these lots of 

 eggs had hatched by October 17. 



Experiment No. 17. Exposure made November 9. In this experi- 

 ment five boxes of badly infested plug cut smoking tobacco were 

 exposed to X-rays for one hour. Parallel spark gap five inches at 

 beginning of experiment; average 3f inches. Current two milliam- 

 peres. One 7-inch tube used. Material exposed was placed directly 

 beneath the tube, distant from target 10^ inches. The tin covers 

 of the trobacco boxes were opened. All stages of the beetle were 

 present. The tobacco was not disturbed, except to open the paper 

 covering over which the lids of the boxes fitted. Directly after 

 exposure, the covers of the boxes were closed and the boxes placed 

 in a tight receptacle so that the beetles could not escape, or further 

 infestation occur from beetles coming in from without. Five boxes 

 of infested tobacco similar to those exposed were prepared in like 

 manner and kept as a check. On November 11, the material was 

 examined and adults, larvae and pupae were apparently normal. On 

 November 12 the material was shipped to the laboratory at Clarks- 

 ville, Tenn., and was placed in a greenhouse soon after arrival. Fre- 

 quent examinations of this material in the past few weeks have shown 

 that the treated material has been developing normally in every 

 respect, corresponding to the development of the check material. 

 In the treated material, larvae have continued to pupate, pupae have 

 become adult, and the newly emerged adults that were isolated have 

 deposited eggs. This material is being kept to observe any possible 

 effect upon the second generation. 



The experiments just discussed were performed upon the com- 

 mercial machine which produced rays of high penetration but very 

 few of the Gamma, or burning rays. In order to test the effects of 

 the Gamma rays. Experiment No. 14, was performed upon a thera- 

 peutic machine consisting of a coil, a chemical interrupter, and an 

 electrolytic rectifier. This form of rectifier, instead of changing 



