8 BULLETIN 252, TJ. S. DEPARTMENT OF AGRICULTURE. 



Number of eggs per female. — No attempt was made to isolate 

 fertilized females for the purpose of securing individual egg-laying 

 records. However, by dividing the number of eggs laid by the 

 number of female moths the average was computed. In Table IV 

 it will be seen that 236 female moths were confined with 204 males 

 in 24 cages. A few eggs were laid upon the sides of the cages, but 

 these were not included in the computation. The number of eggs, 

 exclusive of those laid upon glass, was 7,546, which number when 

 divided by 236 gives an average of 31.974 eggs per female. 



Length of life of motlis. — Observations on the length of the life of 

 191 male moths and 229 female moths are shown in Table V. The 

 average life of the male moth was 10.685 days; of the. female, 12.253 

 days. Maximum number of days for male moth 34, for female 38; 

 minimum number of days for male moth 2, for female 2. 



Table V. : — Length of life of male and female moths of the spring brood in captivity; sum- 

 mary of records of 420 individual moths, Winthrop, Me., 1913. 



Male. 



Female. 



Male. 



Female. 



Length 

 of life. 



Number 



Length 



Number 



Length 



Number 



Length 



Number 



of moths. 



of life. 



of moths. 



of life. 



of moths. 



oflile. 



of moths. 



Days. 





Days 





Days. 





Days. 





2 



3 



2 



1 



22 



2 



22 



1 



3 



7 



3 



5 



23 



2 



23 



5 



4 



5 



4 



4 



• 24 







24 



3 



5 



15 



5 



12 



25 



1 



25 



2 



6 



15 



6 



11 



26 







26 



1 



7 



20 



7 



18 



27 



2 



27 



1 



8 



22 



8 



13 



28 







28 



2 



9 



24 



9 



24 



29 







29 



2 



10 



13 



10 



20 



30 



1 



30 







11 



5 



11 



20 



31 



2 



31 







12 



7 



' 12 



15 



32 







32 



2 



13 



6 



13 



3 



33 







33 







14 



9 



14 



19 



34 



2 



34 







15 



5 



15 



10 



35 







35 







16 



6 



16 



9 



36 







36 







17 



4 



17 



6 



37 







37 







18 



1 



18 



5 



38 







38 



1 



19 

 20 





19 



20 



3 











4 





191 





229 



21 



3 



21 



1 









Average length of life of male moths, 10.685 days; female moths, 12.253 days. 

 Maximum length of life of male moths, 34 days; female moths, 38 days. 

 Minimum length of life of male moths, 2 days; female moths, 2 days. 



THE FIRST GENERATION. 



FIRST BROOD OF EGGS. 



Length of incubation. — During the period of oviposition a record 

 of 7,546 eggs was kept, Of this number 7,493 (99.29 per cent) 

 hatched. The average number of days from the time of oviposition 

 to the appearance of the red ring was 2.507; maximum, 5 days; 

 minimum, 2 days. The average time elapsing from the time of 

 oviposition to the appearance of the black spot was 5.580 days; 

 maximum, 7 days; minimum, 4 days. The average incubation 

 period was 8.874 days; maximum, 10 days; minimum, 6 days. 

 The results are given in Table VI. 



