14 



S. DEPARTMENT OF AGRICULTURE 



larvae of spring-brood moths in 1933 had required more than a year 

 to complete growth, the maximum being 380 days. The minimum 

 developmental period, 234 days, for spring-brood moths occurred also 

 in 1933. 



OVIPOSITION AND LONGEVITY 



In 1932, 87 pairs of spring-brood moths were mated and records 

 obtained of egg deposition and longevity, and similar records were 

 kept in 1933 of 18 mated pairs. The records of egg laying and 

 longevity are shown in table 2. 



Table 2. — Oviposition and longevity records of mated pairs of tobacco moths of 

 the spring brood in 1932 and 1933, in the laboratory, Richmond, Va. 





Pairs of 

 moths 



Eggs laid 



Average adult 

 longevity 



Average 



mean 

 tempera- 



Period of emergence ' 



Maxi- 

 mum . 



Mini- 

 mum 



Average 



Males 



Females 



ture for 

 emer- 

 gence 



period 



1932 

 Apr. 21-28 . - 



Number 

 2 

 6 

 34 

 23 

 8 

 4 

 4 

 4 

 2 



Number 



41 



108 



149 



134 



206 



75 



72 



93 



173 



Number 

 13 

 14 

 9 



16 

 17 

 27 

 9 

 24 

 78 



Number 

 27.0 

 65.5 

 65.8 

 57.7 

 96.0 

 49.0 

 31.0 

 60.0 

 125.5 



Bays - 

 ( 2 ) 

 6.6 

 9.9 

 8.6 

 7.5 

 5.0 

 5.3 

 7.0 

 5.0 



Bays 

 8.0 

 8.3 

 8.6 

 9.7 

 8.4 

 8.0 

 6.8 

 7.8 

 8.0 



° F. 



57 



Apr. 28-May 5 



May 5-12 



66 

 75 



May 12-19 



May 19-26 



Mav26-June2 



70 

 70 

 73 



June 2-9 



78 



June 9-16 



75 



June 16-23 



78 







Total . 



87 





























1933 

 Apr. 14-21 



1 

 6 

 1 

 4 

 1 

 

 

 4 

 1 



31 

 80 

 72 

 260 



84 



31 



1 



72 



56 



84 



31.0 

 40.8 

 72.0 

 132.0 

 84.0 



( 2 ) 



7.5 

 ( 2 ) 

 13.7 



9.0 



14.0 

 8.2 

 25.0 

 12.8 

 9.0 



63 



Apr. 21-28 



Apr. 28-May 5 



61 

 70 



May 5-12 



68 



May 12-19 



May 19-26 



76 



77 



May 26- June 2. 













78 



June 2-9 . . 



153 

 80 



76 

 80 



115.3 

 80.0 



10.0 

 7.0 



12.0 

 9.0 



78 



July 9 



85 







Total 



18 





























i Records were made during the day, and those moths that emerged in the early part of the day were 

 counted with one group and those emerging after the count were included in the following period. 

 2 The length of time the adult lived was not determined. 



The greatest number of eggs obtained from a moih in the spring 

 of 1932 was 206 (table 2), while in 1933 one female deposited 260 eggs. 

 The writers are unable to give a satisfacton^ explanation for the 

 great variation in the number of eggs laid by the moths on tobacco. 



The maximum longevity of females in 1932 was 13 days, and in 1933 

 one individual lived for the unusually long period of 25 days. The 

 longest average period in 1932 of 9.7 days was recorded for 23 fe- 

 males that emerged during the period May 12 to 19, with an average 

 mean temperature for the period of 70° F. The higher tempera- 

 tures that prevailed in 1933 appeared not materially to affect the egg 

 deposition and longevity of adults. The female that deposited 260 

 eggs in 1933 is considered exceptional, since this is by far the largest 

 number deposited by an individual reared on tobacco in the labora- 

 tory. 



The quality of cigarette-type tobacco on which moth larvae feed 

 affects the rate of growth and the size of the adult insect. If given 



