382 The University Science Bulletin. 



"A temperature of 140 degrees continued for nine hours literally cooks the 

 larvse or pupse, a temperature of 130 degrees for five hours is fatal, as is also 120 

 degrees for four hours, while 110 for six hours was only partially effective." 



It was also found that wheat could be subjected to a temperature 

 of 150 degrees for eight hours without impairing its germinating 

 properties. In the second report of the state entomologist of New 

 York, Prof. J. A. Lintner, speaking of Tribolium jerrugineum infest- 

 ing grain and flour, says : 



"A naoderate degree of heat, 120 to 130 degrees, continued for a few hours, 

 would in all piobability suffice to kill all the eggs, larvse and pupse in the 

 material, while a higher temperature, perhaps 150 degrees or more, would be 

 needed for the beetles." 



Professor Chittenden, in his paper on "Insects Injurious to Stored 

 Grain," states: 



'"Prior to the adoption of carbon disulphide as a fumigant, heat was relied 

 upon in the destruction of these insects. A temperature of from 125 degrees 

 to 140 degrees Fahrenheit continued for a few hours is fatal to grain insects, 

 and wheat can be subjected to a temperature of 150 for a short time without 

 destroying its germinating power." 



A large number of the experiments of this nature were made rela- 

 tive to the discovery of a method to destroy grain moth, and from 

 the results of these experiments many of the grain insects could 

 probably be destroyed in the same manner, but it would require a 

 higher temperature to destroy the adults than the larvae or pupse. 



In the first experiment about thirty of the adults and larvse were 

 placed in a Petri dish which contained rye seed. A thermometer 

 was placed in the vial, with the bulb resting in the middle of the 

 rye, in the Petri dish containing the rye grain and various stages of 

 Trogoderma inclusa. The Petri dish was then placed in a dry-heat 

 oven. The bottom and surface of the interior of the oven was 

 covered with asbestos, and the Petri dish was placed upon it, to 

 allow uniform heating. The heat of the oven was raised to 86 de- 

 grees Fahrenheit before proceeding with the experiment. No change 

 was noted in the action of the insects. At a temperature of 100 de- 

 grees the adults and larvae began to crawl out of the grain; at a 

 temperature of 110 degrees both larvse and adults manifested ex- 

 cessive excitement, and were making every effort to escape. They 

 continued to be cjuite active until the temperature of 115 degrees 

 was reached. At this temperature the adults and larvse became less 

 active, and at a temperature of 118 degrees the adults were all dead, 

 and also a large number of the larvse. At a temperature of 119 

 degrees there was no sign of life. To be sure that I had killed all of 



