CODLING MOTH IN NORTHWESTERN PENNSYLVANIA. 



91 



Table XXVI. — Longevity of male and female moths of the first brood. Summary of 

 records of 149 individual moths. 



Male. 



Female. 



Male. 



Female. 



Length 



Number 



Length 



Number 



Length 



Number 



Length 



Number 



of life. 



of moths. 



of life. 



of moths. 



of life. 



of moths. 



of life. 



of moths. 



Days. 





Days. 





Days. 





Days. 





2 



3 



2 



1 



14 



2 



14 



7 



3 



1 



3 



4 



15 



3 



15 



3 



4 



3 



4 



2 



16 



3 



16 



6 



5 



1 



5 



2 



17 



2 



17 



7 



6 



1 



6 



4 



18 



1 



18 



2 



7 

 8 



5 

 6 



7 

 8 



G 

 5 







19 

 20 



1 

 1 







9 

 10 

 11 

 12 



9 

 4 

 3 



5 



9 

 10 

 11 

 12 



4 

 9 



8 

 7 







21 



22 



1 



2 













57 





92 



13 



5 



13 



10 











Table XXVII. 



-Longevity of male and female moths of the first brood. Summary of 

 Table XXVI. 



Observations. 



Life of 



male 



moths. 



Life of 

 female 

 moths. 



Average 



Days. 

 9.79 

 18 

 2 



Days. 

 11.47 

 22 

 2 









On further testing the rearing results by taking the dates of the 

 maximum emergence of the spring brood of moths (June 24) and the 

 emergence of moths of the first brood (August 26) it will be found 

 that 63 days elapsed. But since the emergence of moths of the first 

 brood was very gradual, reaching its maximum first at the close of 

 the season (fig. 22), it becomes evident that the average of 58.5 days 

 is fairly accurate. 



THE SECOND GENERATION. 



SECOND-BROOD EGGS. 



Incubation period. — From two to three days after egg deposition, 

 a semicircular red ring appears within the egg, which later disappears 

 as the embryo attains further growth. Commonly this condition of 

 the egg is referred to as the " red-ring" stage. A black spot ap- 

 pears in the egg from two to three days previous to hatching, and is 

 caused by the dark-colored portions of the head and prothorax of 

 the future larva which are partly visible through the eggshell. In 

 taking observations on these features of incubation no fixed time can 

 be given, as these changes set in and disappear gradually with the 

 growth of the embryo or young larva. It is of value to know the 

 significance of the "red ring" and the "black spot," as the age of 

 the eggs can thus be approximately determined in the field. 



In the cages eggs were laid daily during the entire egg-deposition 

 period, which extended from August 6 to September 22, and a full 

 record of the incubation period was kept during this time (Table 

 XXVIII). 



