126 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 3 



the accumulated temperature decreases accordingly with the advance- 

 ment of the season. The curve also indicates that but little develop- 

 ment of the codling moth takes place below 55°F. and that it is very 

 slow under 60°F. 



This data is sufficient to indicate the general relation of temperature 

 to the rate of growth, or activity. 



A few days after the presentation of my last paper upon this sub- 

 ject I received the second part of Bachmet Jew's Experimentelle Ento- 

 mologische Studien, published in 1907 (2a). This is an encyclopsedic 



10^ 



30° C. 



30° C. 



Days 



30 



50 



70 



g 



r-t 



E 





tta 



^^-- 



uxt 



i^tjat 



iiJSEsii 



Fig. 18. Relation of temperature to larval and pupal stages of Heliothis 

 ohsoleta, according to Quaiutance and Girault (original). 



work dealing with all entomological phenomena in their chemical and 

 physical aspects. It is a monumental work which will serve as a 

 guidebook for entomological students of these subjects in the future. 

 In the first part of this work (2) Bachmet jew dealt with the relation 

 of low temperatures to insect life, but in the second part he discusses 

 the whole range of temperature as related to insect activity and brings 

 out the relation of the temperature and time factors with great clear- 

 ness. His views are well summarized in figure 21, briefly as follows: 

 '(2a, p. 859.) For every species there is a certain range of tempera- 

 ture, K to W, in which it is normally active. At a certain point its 

 growth or activity is most rapid, an increase or decrease of tempera- 



