April, '10] SANDERSON : TEMPERATURE AND INSECT GROWTH 125 



The pupal stage has been similarly plotted from his data, figure 20, 

 and with it are given the records of Melander and Jenne (16) in the 

 Yakima Valley, Washington, in 1904, those of Gillette in Colorado in 

 1901 and our own for the last four seasons and for rearings made at 

 constant temperatures. It is interesting to note the close approxima- 



30° c. 



Days 



Fig. 17. Relation of temperature to incubation of eggs of Heliothis ohso- 

 Jeta. according to Quaintance and Girault ( original ). 



tion to the curve of all this data from diverse sources. Later we hope 

 to be able to make a more complete study of the relation of tempera- 

 ture to the codling moth. The subject is complicated with the pupa 

 of this insect by the fact that the spring pupge may be derived from 

 the two broods of the previous year, w^hich may possibly be differently 

 affected by temperature. The curve for the codling moth pupa also 

 shows how quickly it is influenced by temperature, showing why it is 

 that so much longer is recptired for the pupa in early spring and how 



