THE TOBACCO BEETLE. 41 



The amount of material varied from a few ounces of tobacco up to 

 20 pounds of loose tobacco or tobacco refuse, and the time of treat- 

 ment varied from 11 hours to 30 days. Exposures of over 5 days, 

 in all experiments, gave satisfactory results, the tobacco being com- 

 pletely sterilized. A bale of infested cigar tobacco kept in cold stor- 

 age for 28 days under the conditions mentioned above at a tempera- 

 ture of approximately 14° F. was found to have been completely 

 freed from all stages of the beetle. 



EFFECT OF COLD. STORAGE ON EGGS OF THE TOBACCO BEETLE. 



A large number of separate experiments were made with eggs of 

 the tobacco beetle to determine the effect of low temperatures in cold 

 storage. In these experiments eggs were placed in cigars and exposed 

 at temperatures ranging from 12° to 20° F., the length of exposure 

 varying from 24 hours to 16 days. All boxes of cigars were wrapped 

 with paper. After removal from cold storage the material was placed 

 in an incubator and kept at a constant temperature of 86° F. with 

 humidity from 80 to 90 per cent. The checks were kept in the same 

 incubator until the period of incubation had passed. In these experi- 

 ments none of the eggs exposed to cold hatched, while hatching of 

 the check lots was normal. 



In another series eggs on leaf tobacco or in cells on microscope 

 slides were exposed. Exposures to cold were made without special 

 protection such as ordinarily is afforded by the food substance of the 

 insect. Other conditions of the experiments were practically the 

 same as described in the preceding series. The time of treatment 

 ranged from 5 hours to 7 days, with temperatures varying from 14° 

 to 18° F. In most experiments in which the time of exposures was 

 shorter than 24 hours, the temperature was constant at 14° F. Ex- 

 posures of less than 24 hours did not give satisfactory results, as all 

 or part of the eggs hatched in most of the experiments. In experi- 

 ments in which the duration of treatment was more than 24 hours 

 all eggs were killed. 



EFFECT OF REFRIGERATION ON QUALITY OF MANUFACTURED TOBACCO. 



In order to determine whether or not cold storage seriously in- 

 jures manufactured tobacco, cigars, cigarettes, and smoking and 

 chewing tobacco were placed in cold storage for periods ranging 

 from 30 to 50 days. The stock used for the experiment was fresh 

 and in good condition. An exact duplicate of each brand was kept 

 for the same period, in perfect condition, in the humidor or storage 

 room at a cigar store. Part of the material put in cold storage was 

 in sealed metal containers and part merely wrapped with paper in 



