22 BULLETIN 737, U. S. DEPARTMENT OF AGRICULTURE. 



follows: Number of pairs of beetles under observation, 44; average 

 length of life of males kept without food, 23.4 days; average length 

 of life of males kept with food, 21 days; average length of life of 

 females kept without food, 31.2 days; average length of life of 

 females kept with food, 30.5 days. 



Another series of experiments was made to determine the length 

 of life without food at ordinary room temperatures in summer. 

 Twenty-three pairs of beetles were placed in separate tubes directly 

 after emergence. The average length of life was 21 djays for the 

 males and 40.4 days for the females. Records from 24 pairs of 

 beetles kept under observation at Clarksville, Tenn., during August 

 and September, 1916. by Messrs. J. E. McMurtrey and E. H. Vance 

 show an average length of life of 17.7 days for males and 21.4 days 

 for females. An average of 30 eggs per female was obtained. The 

 greater number of eggs was deposited between the third and the 

 eighth day after egg-laying began. The period of oviposition 

 ranged from the first until the seventeenth day after mating was 

 observed. A similar experiment during the same period with 18 

 pairs of beetles kept without food gave the following: Average num- 

 ber of eggs deposited per female, 24; average number of days males 

 lived, 21.2; average number of days females lived, 26.3. 



OVIPOSITION. 



Egg-laying usually begins in from 2 to 6 days after emergence. 

 A large proportion of the females kept under observation commenced 

 laying eggs the second and third day after mating. Indoors, where 

 infested material is kept warm and is not subjected to much varia- 

 tion in temperature, the eggs may be found at any time. Humidors 

 for storing cigars and tobacco usually are in steam-heated buildings, 

 and the warmth and moisture conditions foster continuous reproduc- 

 tion throughout the year. Eggs usually are not deposited at tem- 

 peratures below 70° F. The adults are more active at high tempera- 

 tures, and eggs are most abundant in tobacco during the warmer 

 period in summer. In the Middle and Northern States, when to- 

 bacco is subjected to approximately out-of-door conditions of tem- 

 perature in unheated buildings, the eggs are laid only during the 

 warmer months of the year. At Richmond, Va., the last eggs were 

 obtained on October 28, 1914, from beetles kept in unheated build- 

 ings and the first eggs were obtained on May 2 of the following 

 spring. Under ordinary conditions the eggs are deposited singly, 

 usually in depressions or folds of the food substance. Owing to their 

 small size and secluded location they do not ordinarily attract atten- 

 tion. Even to many who are thoroughly familiar with other stages 

 of the beetle in tobacco the egg is an unfamiliar object. 



