12 



BULLETIN 932, U. S. DEPARTMENT OF AGRICULTURE. 



temperatures, than was the pupal period of those insects that trans- 

 formed later in the spring.- The average length of the pupal stage 

 was 27.58 days, the maximum 34 days, and the minimum 15 days. 



Table IV. — Length of the pupal stage of pupce of the spring brood of the cod- 

 ling moth, Grand Junction, Colo., 1915. 



Date of 

 pupation. 



Num- 

 ber of 

 individ- 

 uals. 



Length of the pupal stage in specified days. 



15 



21 



22 



23 



24 



25 



26 



27 



28 



29 



30 



31 



32 



33 



34 



Apr. 14 



16 



18 



19 



20 



21 



23 



24 



25 



26 



27 



28 



29 



30 



May 1 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



16 



17 



18 



21 



22 



23 



24 



25 



26 



27 



28 



30 



June 7 



1 

 1 

 2 

 2 

 2 

 7 

 1 



2 



10 

 7 



18 



10 



8 



3 



3 



3 



1 



3 



15 



15 



7 



2 



21 



20 



17 



10 



6 



3 



6 



4 



1 



1 



3 



2 



1 



1 



2 



2 



6 



1 



233 



























1 

 1 























































1 



1 

























1 







1 

 2 

 1 



















































1 



5 

























1 





















1 



2 

 1 

 1 



3 

 6 

 2 

 4 

 1 









3 



4 

 6 

 3 



1 

























6 

























1 



6 

 2 

























2 













































1 



"2" 

 1 











































2 

 1 



"2" 







































1 























1 

 4 

 10 

 1 

 1 



2 

 11 



"i 



.... 

















































1 



1 



3 



2 





1 





































1 





















1 





1 



5 

 6 

 3 

 7 

 3 

 2 



8 



10 



12 



1 



3 



.... 



4 

 2 

 2 

 1 





1 











2 















































1 











































1 

 2 





















1 



i 

 i 



1 







































1 

 1 

 1 

















































1 

 1 



1 

 1 

 1 















































































1 



























1 

 2 



1 

















































.... 



1 



6 





















































7 



6 



9 



22 



19 



7 



32 



39 



25 



21 



23 



13 



5 



4 



Days. 



Average length of pupal stage : 27. 58 



Maximum length of pupal st age 34 



Minimum length of pupal stage 15 



MOTHS OF THE SPRING BROOD. 



Time of emergence. — The tabulated data of the emergence of 

 1,539 moths of the spring brood are given in Table V. It will be 

 noted in this table that the first moths issued May 12, while the last 

 moth of this brood did not emerge until June 29 or nearly seven 

 weeks later. The emergence is largely dependent upon temperature 

 and atmospheric conditions and hence the number of moths issuing 

 daily fluctuates more or less in accordance with the climatic factors. 

 The number of moths appearing daily gradually increased (with 



