2 DEcnmous fruit insects and insecticides. 



On March 24 there were taken, from rubbish on the ground under 

 an outdoor apple bin at a vinegar factory, 6 pupae and 130 larva?. 

 They were located in a damp place, shaded during the greater part 

 of the day. Above, in crevices of the apple bin, were many cocoons, 

 for the most part inaccessible, but those that could be examined 

 showed a much larger proportion of pupae. 



On March 31 some timbers were pried from this bin and larvae and 

 pupae were found in about equal numbers — 122 larvae and 112 pupae. 

 This bin was situated on the west side of the building and was built 

 of 2 by 4 material, nailed, 1 inch apart, to large supporting timbers. 

 The cocoons occurred between the scantlings and their supports. 

 This should represent fairly normal conditions above ground. Even 

 here pupae would be found greatly in the majority under one scant- 

 ling, while beneath an adjoining one nearly all cocoons might contain 

 larvae. This was evidently due to the fact that some of the pine 

 scantlings were sapwood, which absorbs much moisture during rains. 

 At the time of examination they were damp and soggy, though no 

 rain had fallen for several days. Under these the proportion of 

 pupae was much smaller than under dry scantlings adjoining. 



No empty pupal cases were found March 31, although one adult 

 moth, evidently just emerged, was captured while sunning itself on 

 the bin. On April 21 the bin was again examined, and there were 

 found 79 larvae, 114 pupae, and 64 empty cases. This showed that 

 about 70 per cent of the wintering larvae had pupated up to that 

 time. But even yet larvae were in the majority in damp and shaded 

 parts. 



Nearly all of the larvae collected on the above dates and kept out 

 of doors in vials had pupated by May 12. Two belated individuals 

 pupated May 19 and 20. This gives a probable time of 2\ months 

 during which wintering larvae transformed to pupae. Apple trees 

 bloomed about the middle of this period. The majority of the 

 spring pupae had given out adults by May 27, the two belated indi- 

 viduals emerging June 6 and 8. Thus there is a period of about 3 

 months during which spring pupae were present — from the first of 

 March until June. 



"Length of spring pupal stage. — Individual records were obtained of 

 131 spring pupae, from larvae collected at the out door apple bin. 

 The material was kept out of doors in vials in a pasteboard box, 

 under as nearly a normal temperature as possible. The length of the 

 pupal stage steadily decreased with the advancement of the season. 

 Doubtless a longer period would have been shown for the first pupae 

 of the season if they could have been observed. 



The records of the spring pupal stages are given in Tables I and II, 

 with a summary in Table III. 



