THE TOBACCO BEETLE. 31 



exposure extended from November, 1913, until March, 1914. A self- 

 registering thermometer in the open building showed the lowest tem- 

 perature to be 12° F., and this temperature was reached several times 

 during the winter. The lowest point reached in the cellar was not 

 determined, but the protection afforded gave somewhat higher tem- 

 peratures than obtained in the open building. On examination in 

 March a very few live larva? were found in the tobacco kept in the 

 cellar. The tobacco in the open building was completely sterilized. 

 The package was sealed and kept under observation until June, 1914, 

 but no live stages of the beetles were found. 



AT OAK HARBOR, OHIO, WINTER OF 1914-15. 



A package prepared at Richmond, Va., contained about 5 pounds 

 of heavily infested smoking tobacco, part pressed or sliced plug and 

 the rest granulated, and a package of infested cigars and cigarettes. 

 About 1,000 eggs of the tobacco beetle had been placed in the smoking 

 tobacco November 1, 1914. This was mailed on November 14 to Oak 

 Harbor, Ohio, where it was placed in an unheated building on No- 

 vember 17. It was examined June 10, 1915. No live stages of the 

 beetle were found. The lowest temperature registered in the building 

 was 10° F. 



AT CLARKSVIIXE, TENN., WINTER OF 1915-16. 



About 10 pounds of smoking tobacco wrapped in paper were kept 

 over winter in an unheated room in the laboratory. The tobacco con- 

 tained all stages of the beetle. On November 1, 1915, about 1,000 

 eggs of the beetle were placed in the tobacco. These eggs hatched 

 about November 10. No record was secured of the lowest tempera- 

 ture in the room. The lowest record out of doors was 5° F. The 

 tobacco was examined during April, 1916. No live stages of the 

 beetle were found. Although the tobacco was kept under observa- 

 tion for several months no signs of infestation were observed. 



Evidence of the effect of freezing on the tobacco beetle has been 

 observed on numerous occasions and it is not uncommon to find leaf 

 tobacco or other food substances which have been exposed to low 

 temperatures completely free from the beetle although its condition 

 showed that it had been heavily infested previously. It has been the 

 experience of those familiar with the tobacco industry that beetles 

 always become more abundant and destructive after a mild winter. 



DRYING OUT OF FOOD SUBSTANCES. 



The tobacco beetle thrives best in tobacco that is protected from 

 rapid evaporation and when the humidity is high. If the tobacco 

 ?«Tnains very dry for a considerable length of time the rate of multi- 



