CODLING MOTH IX SANTA CLARA VALLEY. 143 



maximum about August 1 1, while the second-brood larvae hatched from 

 July 13 until October 12 with a maximum about August 20. The 

 second-brood larvae cocooned August 16 and on throughout the winter, 

 with a maximum about September 16. The wintering larvae of the 

 first brood ''to spin cocoons" began to do so about June 15, but by far 

 the largest number of these came from the second or true overwinter- 

 ing brood. The life cycle of the codling moth from the first appear- 

 ance of the spring pupae until the last larva of the first brood cocooned 

 occupied about six months. The second-brood life cycle from the first 

 appearance of the first-brood pupae up to the cocooning of the winter- 

 ing larva? in 1911 occupied a period of over eleven months. 



SEASONAL-HISTORY STUDIES FOR 1911. 

 SPRING BROOD OF PURE. 



Time of pupation. — Records for the spring brood were kept in two 

 series, one lot in small gelatin capsules, size No. 0, punctured with a pin, 

 and the other in vials. Those in the capsules were taken from under 

 bands in February and out of the larvae thus secured only 41 per cent 

 pupated. Of those that pupated 21.7 per cent died, the majority of 

 these being early pupating individuals. The first larva pupated on 

 March 2, the second March 14, and none after that until the last week 

 of the month. Pupation continued until May 11, on which date the 

 last larva became a pupa. The first adult appeared April 18 and the 

 last June 8. Thus the actual period of time when pupae were present 

 extended from March 2 to June S, or 98 days. In the field, however, 

 adults were emerging from March 24 to June 20; thus pupae were 

 present from about February 12 until June 20, or 128 days. The 

 longest pupal stage was 49 days, the shortest 30, and the average 41.9 

 days. Figure 32 shows the time of pupation for both capsule and vial 

 material and also daily mean temperature. These data were com- 

 piled from records of 156 individuals. 



Second series of larvse. — Larvae were taken from bands in the fall 

 of 1910 and placed in vials, where they remained through the winter. 

 Of these 25.2 per cent died before pupating and of the ones that 

 developed into pupae 23.2 per cent perished. The earliest pupa 

 occurred March 16 and the latest May 11. The earliest adult issued 

 April 26 and the latest June 11. Therefore the period when pupae were 

 present, March 16 to June 11, amounted to 87 days. The shortest 

 pupal stage was 31 days, the longest 56, and the average 43.2 days. 

 This exceeds the average for the capsule series by 1.3 days. There 

 were 66 individuals in the vial series, of which 32 were males and one 

 escaped before its sex could be determined. No attempt was made 

 to credit any certain sex to the larvae w T hile in that stage as was done 

 in 1910. The average male pupal stage was 41.8 days, while that 



