98 DECIDUOUS FBUIT INSECTS AND INSECTICIDES. 



two broods of larvae it will be noted that the first brood exceeded in 

 number the second brood about five times. Considering the number 

 of transforming larvae and the number of wintering larvse of the first 

 brood, it was found that only one-fourth of the brood completed the 

 life cycle the same season, while three-fourths of the brood hiber- 

 nated, attaining their full development with individuals of the second 

 brood. 



REVIEW OF THE LIFE-HISTORY WORK OF 1909. 



During 1909 an attempt was made to rear the codling moth through- 

 out the season, and to determine the time and relative occurrence of 

 the different stages of the two broods. The essential results of 

 observations for the season are shown in the diagram (fig. 22). 

 The moths in the spring commenced to emerge June 11, reaching a 

 maximum of emergence June 24. Moths of the following brood — 

 the first-brood moths — appeared from August 2 to September 3, 

 with a maximum August 26. Oviposition generally took place the 

 fifth day after the emergence of the moths of either brood. The 

 time during which the first brood larvae attained maturity extended 

 from July 10 to the end of September. Only one-fourth of the 

 larvae of this brood transformed and completed the life cycle the 

 same year, while three-fourths of the larvae hibernated. Of the 

 second brood, mature larvae appeared first on September 11 and 

 continued to appear until the middle of November, at which time 

 quite a number was prevented from further growth and failed to 

 enter hibernation places because of prevailing low temperature. 

 Judging by the number of larvae collected from the banded trees, 

 individuals of the first generation exceeded in number the second 

 generation five times. 



SEASONAL-HISTORY STUDIES OF 1907 AND 1908. 



SOURCE OF REARING MATERIAL. 



The rearing material for the spring of 1907 was collected from a 

 cider bin May 9, before any larvae had transformed. Later in the 

 season larvae were obtained from banded apple trees, which were 

 then used partly the same year and partly (overwintering larvae) for 

 emergence records of moths the following spring. Additional band 

 material was obtained in 1908, which, together with a small number 

 of reared larvae, constituted the entire supply used that year. 



The rearing work for the two seasons of 1907 and 1908 was carried 

 out on an open porch of the laboratory building, or out of doors under 

 trees in the laboratory yard, and it is thus believed that the records 

 of observations represent the normal transformation of the insect 

 in orchards. 



