58 BULLETIN 429^ U, S. DEPARTMENT OP AGRICULTURE. 



THE SECOND BROOD OF LARV.E. 



Le7igth of feeding period. — The feeding period of second-brood larvae 

 is somewhat shorter than has been recorded for the first-brood 

 larvae, and is mainly the result of warmer and more settled weather 

 conditions than were prevalent at the time the first-brood larvae 

 were feeding within the fruit. A more advanced stage of the fruit 

 at this later period of the season was also probably conducive to a 

 shorter feeding period. Of the 505 larvae of the second brood under 

 observation, one individual insect completed the feeding period in 

 14 days, the shortest time recorded, while the longest time was 34 

 days, thus making a range of variation of 20 days. An average of 

 19.7 days is computed on the whole number under observation, 

 including both wintering larvae and those transforming the same 

 season. These records will be found in Table XLIII. The averasre 

 length of the feeding period of larvae of the first brood was 24.45 

 days, thus making an average of 4.75 days greater than larvae of the 

 second brood. Records on the corresponding period obtained during 

 the season of 1912 show an average of 21.23 days. 



Feeding period of wintering larvse. — During the period of observa- 

 tions conducted with individuals of the second brood a total of 505 

 larvae was used, and of this number 100 larvae, or 19.98 per ,cent, 

 proved to be wintering larvae. In Table XLIV it is shown that a 

 maximum of 34 days is found to exist for the feeding period and a 

 minimum of 15 days, covering a range of variation of 19 days, with 

 an average feeding period of 21.13 days. This period is 1.43 days 

 greater than the average time for the transforming larvae of the same 

 brood, and is found to be practically identical with the corresponding 

 period of the second generation during the preceding season. 



