CODLING MOTH IN SANTA CLAKA VALLEY. 



135 



generation being 12.4 days plus 3 days makes 15.4 days, to be added 

 to each period where the larva was reared to a moth. 

 A summary of Table XV shows the following data: 



Table XXIII. — Summary of Table XV showing the theoretical life cycle of the first 



generation. 



Number 

 of indi- 

 viduals. 



Length of 

 life cycle. 



Number 

 of indi- 

 viduals. 



Length of 

 life cycle. 



Number 

 of indi- 

 viduals. 



Length of 

 life cycle. 



Number 

 of indi- 

 viduals. 



Length of 

 life cycle. 



1 



2 



1 



1 



2 



Days. 

 72.4 

 90.4 

 58.4 

 97.4 

 80.4 



1 



2 



4 



1 



2 



Days. 

 89.4 

 88.4 

 75.4 

 83.4 

 87.4 



1 



3 



3 



1 



2 



Days. 

 74.4 

 77.4 

 67.4 

 91.4 

 65.4 



1 



1 



1 



1 



Days. 

 76.4 

 68.4 

 64.4 

 101.4 



A summary of Table XXIII shows the average life cycle to be 

 78.62 days, the maximum 101.4 days, and the minimum 58.4 days. 

 The average length of the egg stage, 12.4 days, added to the average 

 feeding period of the larva?, 38.1 days, added to 11.7 days, the average 

 postlarval stage, added to 19.4 days, the average pupal stage, added 

 to 3 days' time before oviposition, makes a total of 84.24 days, which 

 is about 6 days more than was obtained by actual rearing records. 



SECOND GENERATION. 



SECOND BROOD OF EGGS. 



Incubation period. — The same methods were used for obtaining 

 eggs of the second generation as were practiced on the first genera- 

 tion, viz, placing moths in Riley cages in which apples were suspended 

 by strings. Nearly all of the moths were utilized for this work 

 throughout the emergence period, thus giving practically the true 

 period of oviposition that would naturally obtain in the field. In 

 this manner eggs were obtained from July 9 up to September 25, 

 inclusive, a period of 78 days. Eggs were obtained in the cages the 

 day after the emergence of the earliest first-brood moths, and three 

 days after the last first-brood moth emerged. Moths emerged in 

 such small numbers during the month of September that proper 

 mating was hindered and consequently few eggs were deposited 

 after the last moth emerged. 



A record was kept of the second-brood eggs, as with the first-brood 

 eggs, showing the length before the red ring appeared and before 

 the black spot appeared, both of which indicate distinct periods, so 

 that when eggs are obtained in the field they can be classed accord- 

 ing to their age with some degree of accuracy. 



In the cages eggs were obtained practically every day from July 9 

 to September 25, and in all a total of 1,861 eggs were kept under 



