98 



DECIDUOUS" FRUIT INSECTS AND INSECTICIDES. 



The time required for the larvae to reach maturity was determined 

 for 203 individuals, as is shown in Table I. The average time for 

 all larvae was found to be 28.05+ days, the maximum being 35 

 days and the minimum 24 days. 



The length of the larval period for 1912 was doubtless longer than 

 during a normal season. The weather conditions that prevailed 

 ■throughout the spring of 1912 were to some degree exceptional. 

 During the larval development from May 4 to 17, inclusive, the 

 weather was exceptionally cool, the maximum temperatures for these 

 days ranging from 38° to 76° F. 



In the rearing cages the larvae, when full grown, invariably trans- 

 formed into pupae in the rolled-up leaves upon which they had been 

 feeding. In a few cases larvae were seen pupating on the bottom of the 

 cages. In the field larvae usually change to pupae in the rolled-up 

 leaves. In a few instances they have been observed making the 

 transformation on the bark of the trees, where no protection was 

 afforded the pupae. 



PUPAL STAGE. 



The length of the pupal period for 128 individuals is shown in the 

 following table: 



Table II. — Length of pupal stage of the fruit-tree leaf-roller. Canon City, Colo.. 1912. 



Date 



larvse 



pupated. 



Number 

 of pupae 

 under ob- 

 servation 

 from which 

 moths 

 emerged. 



Moths emerging in specified days 

 from date of pupation. 



9 



10 



I 

 11 12 



13 



14 



15 



Total 



num- 

 ber of 

 days. 



Mav 28 

 Mav 29 

 Mav 30 

 May 31 

 June 1 

 June 2 

 June 3 

 June 4 

 June 5 

 June 6 

 June 7 

 June 8 

 June 9 

 June 10 

 June 13 



•i 



1 



4 1 











6 .... 2 | 3 1 

 17 ! 2 1 2 6 5 









2 









10 1 -1 -3 1- 3 2 1 









5 



7 I 1 

 18 ! 2 

 15 i 2 



2 

 3 

 3 

 4 

 1 

 1 



1 2 













2 1 

 6 5 

 5 2 



1 2 



2 \ 3 



1 .... 



3 1 



2 1 



3 2 



4 



..1. . 







1 

 1 

 3 

 2 



1 



1 

 1 

 2 

 1 











10 

 10 

 2 

 4 

 3 

 8 





1 



1 





























2 

 3 



1 

























128 8 



27 



46 28 



12 



5 



2 1,440 



Average time for all individuals, 11.25 days. 



The earliest larvae to pupate were observed on May 28, and the 

 latest ones on June 13. The days spent in the pupal state varied 

 from 9 to 15 days, the average for 128 individuals being 11.25 days 

 as is shown in Table II. 



