118 BULLETIN 932, U. S. DEPARTMENT OF AGRICULTURE. 



Length of pupal stage of second brood. — The average length of 

 the pupal stage of the pupae of the second brood in 1915 was 15.62 

 days, the maximum 31, and the minimum 11. In 1916 the average 

 length of the pupal stage was 13.51 days, the maximum 16, and the 

 minimum 11. 



Oviposition by moths of the second brood. — No oviposition data 

 were obtained in 1915 owing to the fact that the eggs deposited by 

 the moths of the second brood failed to hatch. In 1916 fertile eggs 

 were deposited, but since moths emerging on different dates were 

 confined in the same cages no oviposition data were obtained. 



Number of eggs per female moth of the second brood. — In 1915 

 no fertile eggs were deposited, but in the following year the aver- 

 age number of eggs per female moth was 45.58. 



Length of life of moths of the second brood. — The moths of the 

 second brood of the seasons of 1915 and 1916 were not confined in 

 separate cages according to their time of emergence. For this rea- 

 son no data were obtained. 



Life cycle of the second generation. — The life cycle of the second 

 generation in 1915, as determined by rearing, was as follows : Aver- 

 age length of incubation period 6.12 days, average larval feeding 

 period 20.49 days, average cocooning period 8.56 days, average pupal 

 period 15.62 days, and average life cycle 50.81 days. In 1916 the 

 records show that the average length of the incubation period was 

 6.01 days, the average larval feeding period 18.08 days, the average 

 cocooning period 4.78 days, the average pupal period 13.52 days, and 

 the average life cycle 42.40 days. 



THE THIRD GENERATION. 



Embryological changes and length of the incubation period of 

 third-brood eggs. — In 1916 the average number of days from the 

 date of deposition to the appearance of the red ring was 2.49, the 

 maximum 5, and the minimum 2 ; the average number of days from 

 the date of deposition to the appearance of the black spot was 6.36, 

 the maximum 9, and the minimum 6 ; the average incubation period 

 was 7.77 days,« the maximum 11, and the minimum 7. 



Length of feeding period of third-brood larvce. — The average 

 larval feeding period of the third-brood larvae in 1916 was 37.55 

 days, the maximum 68, and the minimum 20. 



PERCENTAGE OF TRANSFORMING LARViE. 



Percentage of transforming larvce of the first brood. — In 1915 

 47.52 per cent of the first-brood larvae transformed, while in the 

 following season 74.15 per cent pupated. 



Percentage of transforming larvce of the, second brood. — In 1915 

 1.08 per cent of the second-brood larvae transformed. In 1916 6.71 

 per cent of these larvae transformed. 



