October, '21] quayle: codling moth in walnuts 443 



The Third Gexeration 



. Third Brood of Eggs and Larvae. Eggs and young larvae of 

 this partial brood, appear in September and October. Recently hatched 

 lar\^ae have been observed to enter the nuts as late as the second week in 

 October. When the nuts are harvested, while most of the larvae are 

 mature, many will be found in various stages of development. 



Seasonal Life History at Santa x\na 



The wintering larvae in their cocoons began to change to the pupae 

 late in March and continue to pupate until the middle of June. The 

 first m.oths appear during the m.iddle of April, the peak of emergence 

 occurs about June 1st, and the last of the brood emerges. The peak of 

 egg la\nng by this spring brood of m.oths occurs the first week or two of 

 June, while the first week of May and the first week of August represent 

 respectively, the beginning and end of the brood. The peak of the ap- 

 pearance of the larvae occurs about June 10, while May 15 and July 15 

 represent respectively the beginning and end of the brood. The peak of 

 the appearance of the moths of the first brood occurs the first week of 

 August. Second brood eggs appear in maximum numbers August 10th. 

 Second brood larvae second week of August, and second brood moths th'e 

 last week of August. Eggs and larvae of the third generation appear in 

 September and October. The wintering larvae include those of the 

 first second and third broods. Since a few larvae of the first brood show- 

 ed no indication of spinning until disturbed on August 18, 69 days after 

 hatching, as well as other records, indicate that some of the lar^^ae of the 

 first brood do not transform until the following year. There is but one 

 full brood and a partial second and third brood of eggs and larvae. vSince, 

 however, lar\'ae of the first, second and third broods overwinter, there is 

 left but one complete generation of the insect with a partial second and 

 third. 



Seasonal History at Carpinteria 



While an occasional specimen will appear at Carpinteria almost as 

 early as at Santa Ana, the great majority appear much later at Carpin- 

 teria. In 1919 the peak of appearance of the spring brood of larvae was 

 during the first and second weeks of July. In 1920, a warm spring, the 

 peak occurred about the third week in June. There is only a partial 

 second brood of larvae at Carpinteria and no third brood, so far as ob- 

 served. At Santa Ana the greatest amount of injury is done by the 

 second brood larvae in late July, August, and early September, while at 

 Carpinteria the greatest injury is done by the spring brood during the 



