578 WHEELER P. DAVEY 



B. 20 beetles were similarly sealed up, without food, in a space 

 0.05 cubic inch. They were all alive at the end of 3 weeks, but some 

 of them seemed to be stuck together by a fihii of moisture. At the end 

 of 4 weeks, 8 were still alive. 



C. 10 beetles were similar^ sealed up in a space 0.05 cubic inches 

 together with a pinch of white flour. They were all alive at the end of 

 8 weeks. Evidently the flom- had taken care of the bodily moisture 

 noted in B. 



Therefore, Tribolium Confusum are not easily killed by lack of air, 

 provided they are kept dry and have food. 



Experiment 2. To show that the beetles were not killed by some effect 

 of temperature, rather than by X-rays. 



20 beetles were placed in a round-bottom test tube, | of an inch in 

 diameter, well [heat-insulated. Temperature was measured from 

 time to time by means of a delicate thermocouple. The highest tem- 

 perature reached was 27.25°C. 



Therefore, the beetles can not by over-crowding in a heat-insulated 

 space raise their temperature high enough to produce death. 



Experiment 3. To shoiv that the beetles were not killed by mecha7ucal 

 injury rather than by X-rays. 



A. 5 beetles were placed in a tapered test tube. Diameter of test 

 tube was | inch. Length of taper was 1| inch. A small hole in the 

 bottom gave ventilation. The beetles were therefore crowded to- 

 gether, and repeatedly crawled over one another in their efforts to 

 escape. All were alive at the end of 97 hours. 



B. 5 beetles were shaken violently in a glass beaker 50 times a day. 

 At the end of two daj^s, 4 were still alive. At the end of a week, 3 

 were still alive. 



C. In addition, it may be stated that beetles used as 'controls' 

 in the main bodj^ of this work do not seem to be at all affected by being- 

 dropped through a funnel several times daily during the process of 

 counting. 



Therefore, the Ijeetles are not easily given fatal injuries. 

 Experiment 4- To shoiv that the beetles were not killed by NOo rather 

 than by X-rays. 



A. 20 beetles were put in a test tube | inch in diameter with a 

 little corn meal. The test tube was connected to a source of NO2.. 

 All beetles were alive after having been in an atmosphere of NO2 for 

 25 hours. At the end of 64 hours, 5 were alive. 



B. 25 beetles were put in a vial and exposed to dilute NO2 for 5 

 minutes. The concentration of NO2 was such as to distinctly color 

 starch-KI paper in 1| minutes. 23 beetles were found alive after the 

 20th day. But there is not enough ozone and NO2 together in the 

 lead box where the beetles are X-rayed to color starch-KI paper dur- 



MAM 



ing an exposure of 14,000 ^-^ at 50 KV. 



Therefore, there is not enough NO2 produced while the beetles are 

 being X-rayed to affect them. 



