INSECT DIAPAUSE AND ENVIRONMENT 131 



water. All the experimental work on this species has been 

 carried out by H. E. Hinton at Bristol. 



Hestrin: Was any attempt made to grow this fly in the 

 laboratory? 



Lees: Hinton has attempted it. but it has proved difficult. 



Galun: Long day and low temperature induce diapause, 

 while in short days the high temperature induces it. What 

 happens if you artificially reverse one of the conditions, so that 

 you induce with one element and defer with the other. 



Lees: It works additively. If a long day insec ;is given a short 

 day with high temperature, the latter will prevent at least some 

 of the individuals from entering diapause. This lack of tempera- 

 ture com_pensation may be adaptively useful, since rapidly 

 breeding species can complete an additional generation under 

 short dav conditions. 



