THE CODLING MOTH IN MICHIGAN. 



21 



Table XX. — Length of life of moths of the first brood, in confinement, Douglas, Mich., 



1910. 



Number. 



Length 

 of life. 



Number. 



Length 

 of life. 



Number. 



Length 

 of life. 



Number. 



Length 

 of life. 



5 



15 

 14 

 34 

 41 



Days. 

 2 

 3 

 4 

 5 

 6 



70 

 49 

 56 

 27 

 23 



Days. 



8 

 9 



10 

 11 



39 



27 

 18 

 5 

 4 



Days. 

 12 

 13 

 14 

 15 

 16 



9 

 4 

 2 



2 



1 



Days. 

 17 

 18 

 19 

 20 

 24 



Total number of moths, 445. 



Table XXI.- — Length of life of moths of the first brood in confinement, Douglas, Mich. 

 1910; summary of Table XX. 



Observations. 



Length 

 of life. 





Days. 

 8.93 

 24 

 2 



Maximum 



Minimum 



The results of observations on the length of life for the two broods 

 of moths are practically the same (compare Tables XI and XXI). 



LIFE CYCLE OF THE FIRST GENERATION. 



In the preceding pages the separate stages of the first generation 

 have been considered at length, and the length of time of the devel- 

 opment has been determined by a number of experiments for each 

 stage. The final figures from these records thus represent the average 

 life cycle of the codling moth of the first generation. 



Days. 



Incubation period of eggs 6 



Length of feeding of larvae 25 



Time of larvae in cocoons 7 



Length, of pupal stage 13. 6 



Total 51.6 



To test the accuracy of the various experiments for the separate 

 stages an additional experiment was undertaken in which a number 

 of individual insects were carried through from the time of hatching 

 to the emergence of the moths. 



