84 N. H. AGR. EXPERIMENT STATION. [Bulletin 171 



second column are from fall apples in which pupation was taking 

 place about a month later than with the other two lots. The 

 emergence records show a difference of about a week in the 

 maximum emergence between the early and the later pupae. 

 Similarly, in 1910, in the case of pupse from August Sweets and 

 Sops-of-Wine, emergence began distinctly early and seemed to 

 reach an early maximum, being at an end while emergence was 

 still in progress from later pupse. The data are not sufficient 

 for drawing definite conclusions. Various other features, such 

 as the kind of soil, the location of the pupse with reference to 

 shade, and the local conditions of moisture, probably have much 

 influence. 



TWO-YEAR LIFE CYCLE. 



That a proportion of individuals of the Apple Maggot may 

 require two years instead of one to complete the life cycle was 

 discovered in certain records made in 1913. 



In prior experiments it had been found that with many lots of 

 pupse only partial emergence occurred the summer following 

 pupation. 



In 1911 4 lots of infested apples were placed in 4 of the con- 

 crete bins in the open-air work-room of the insectary. These 

 bins contain soil continuous with the earth beneath. The soil 

 tends to dry out somewhat in the surface layers, but is kept more 

 moist when covered with a layer of apples. In 1912 there was 

 ordinary emergence of adults. The contents of the bins remained 

 unchanged. In 1913 each bin was covered with a screen-wire 

 cage. On July 11 adults began to emerge, and emergence 

 continued to July 29, inclusive, 138 adults being secured. The 

 detailed emergence records will be found below in Table 25. 



In three of the bins the apples were a fall variety. These were 

 collected September 1 in one case and September 11 in the other 

 two. The latter were placed in the bins September 15. The 

 remaining lot was an early variety, picked August 10 and placed 

 in the bin August 11. 



Further data secured in 1912 to 1914 are as follows. In 1912 

 three lots of infested apples were brought to Durham and piled 

 on sod. Lot No. 1 consisted of three fourths bushel of August 

 Sweets, and was placed beneath a small hnden tree. Lot No. 2 



