36 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



during the pupal stage of a number of individual insects. These 

 averages were computed from the temperature records of Table 

 LXX, which are from a seh-rec or ding thermometer of the type 

 used by the United States Weather Bureau. The instrument was 

 regulated in accordance with a mercury thermometer and was kept 

 in the rearing shelter throughout the season. The records in Table 

 XXXIII give the date of pupation and the date of emergence of 

 moths for 122 individual insects. 



Fig. 13.— Curve showing relation of temperature to the duration of the pupal stage in the spring brood of 

 the codling moth: Douglas, Mich.. 1911 (from Table XXXV). (Original.) 



Table XXXV. — Average daily temperature during the pupal periods of the spring 

 broods; summary of Table XXXIII. 



Pupal 

 period. 



No. of 

 obser- 



\ ations. 



A-* 



erage mean temperati 



lys. 





tit 



3 



14 



2 



15 



4 



16 



12 



17 



18 



18 



22 



Average. 



Maxi- 

 mum. 



° F. 



F. 



68.31 



69.86 



71.41 



73. 77 



69.19 



70.08 



67.29 



68.56 



67.32 



69.29 



66.50 



68.23 



F «P al obie?- 



Average mean temperature. 



x upai ^ ser . 



Mini- P enod - vations. . Maxi- 



mum. Average. mum _ 



F. 



66.02 



69.06 



68.83 



65.51 



66.06 



65.26 



Mini- 

 mum. 



Days. 



'19 

 20 

 21 

 23 

 24 





° F. 



F. 



23 



65.84 



67.29 



20 



65.65 



66.81 



14 



65.01 



67.58 



2 



65 33 



65.61 



2 



69.52 



71. 73 



° F. 



64.48 



64.53 



64.49 



65.05 



67.32 



Observations on the time of transformation were made once daily 

 and invariably in the afternoon. In Table XXXV a summary of 

 these temperature records is given showing the averages for each day 

 and also the number of individual pupae under observation for the 



