54 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



invested, I can not believe there would be any objection to the ex- 

 pense, especially if they can count on the complete control of the 

 infesting insects. 



Mr. F. L. Washburn : If a housekeeper, who is reasonably clean, 

 finds insects in the flour should not the blame in eight cases out of 

 ten be placed on the mill from which the flour came? 



Mr. G. a. Dean: In nine cases out of ten the infestation can be 

 traced either to the mill or the grocery warehouse in which the flour 

 has been stored. 



Mr. Wilmon Newell: At what temperature will snout beetles in 

 flour mills be destroyed? 



Mr. G. a. Dean: They cannot stand a temperature of 119 degrees 

 for more than two or three minutes. Of course, snout beetles are not 

 serious pests in flour mills. However, in our heating of mills we have 

 often noticed that they are all killed in those parts of the mill near the 

 intake of the grain, which are about the only places where they are 

 found. 



Mr. Wilmon Newell: I asked the question because there are 

 often large numbers of these insects in rice mills and the method of 

 destroying them with heat would, I think, be of value. The injury 

 caused by insects to stored rice is so great that the owners would not 

 hesitate to spend a thousand dollars a season to destroy them. 



Mr. W. H. Goodwin: I think there is an important point which 

 Mr. Dean did not mention and that is that it is best to begin heat- 

 ing the mill in the evening. By beginning the work at this time a 

 fatal temperature is reached the next day, usually between 10 and 

 11 o'clock. One trouble that I have found is that it is almost im- 

 possible to maintain a high temperature after 5 or 6 o'clock in the 

 evening owing to the gradual decrease in the temperature outside. 

 This statement applies especially to conditions in Ohio where the 

 ranges of temperature between afternoon and midnight are often 

 very great. 



Mr. F. L. Washburn: I should like to ask Mr. Goodwin to express 

 his opinion on the value of hydrocyanic acid gas. 



Mr. W. H. Goopwin: I believe hydrocyanic acid gas is of little 

 practical value as a mill fumigant. In all my experiences with this 

 gas in fumigating mills I have not had one perfectly effective result. 

 In every case enough insects survived to reinfest the mill. The gas 

 seems to condense so rapidly that it fails to be effective and the insects 

 are either uninjured or recover rapidly after being subjected to fumi- 

 gation. 



Mr.. T. J. Headlee: In regard to the effect of high temperatures 

 on insect life I desire to report that in the past two or three months 



