436 

 SUMMARY OF CONCLUSIONS. 



(1) Temperatures cannot be summed correctly for biological pur- 

 poses unless readings are taken at intervals of one or two hours instead 

 of daily and corrected for the effects of other conditions besides tempera- 

 ture so as to fit the true curve for velocity of development. Such correc- 

 tion, here called the tcmperatitrc-suhstitution method, is possible only 

 through preliminary experimentation or observation affording tempera- 

 ture and humidity data for the defining of standard conditions. 



(2) The temperature-substitution method, when correctly used, 

 translates the observed conditions into terms of the response of the 

 organism, that is, into developmental units, which can be summed for 

 biological purposes. 



(3) The use of a normal total of developmental units for a stage in 

 the life-cycle of an organism makes possible the calculation of standard 

 average time for the stage. This permits estimation of the amount of 

 individual variation in any given case and the effects of factors other than 

 temperatifre and humidity which make the developmental total larger or 

 smaller than normal. 



(4) Autumn and winter rainfall influence the time of first pupation 

 in spring and the length of the pupal stage. 



(5) Ball-Taylor rainfall-temperature diagrams (hythergraphs) show 

 characteristic differences between years when the codling moth is abun- 

 dant and years when it is scarce. 



(6) Rainfall influences the time which the larva spends in the apple 

 and probably the length of other stages. 



(7) The falling of the mean temperature from day to day in late 

 siunmer is correlated with increased rate of development ; the rising of 

 the mean temperature from day to day in spring is correlated with de- 

 creased rate of development. 



(8) The falling of mean temperatures, or at least minimum tempera- 

 tures, has no apparent effect on the initiation of hibernation. 



(9) The explanation of hibernation phenomena is probably to be 

 sought in the activity of enzymes. 



(10) There is no reliable basis for predicting the time of the first 

 spring pupation. 



