272 



J. Maynard Smith 



be described to discover how far the processes responsible for 

 death in D. subobscura are the same at different temperatures, 

 differing only in the rate at which they proceed, and how far 

 different processes are concerned at different temperatures. 



100-1 



c 4 



4) 



O ^ 



10- 



1- 



J I I L 



J I I I I L 



-1000 



\- 100 ^ 



c 



20 



35 



10 



25 30 



Temperature (°C.) 



Fig. 1. Survival time of flies at different temperatures. A, in food 



vials; B, in saturated air; C, in dry air; A» ^j females; 0> •> 



males; □, ||, sexes combined. 



Figs. 1-3 and Table II reproduced by courtesy of the Editor, 

 Journal of Experimental Biology. 



The mean ages at death (measured from adult emergence) 

 of adults kept continuously at various temperatures are 

 shown in Table I. In Fig. 1 these values are plotted on a 

 logarithmic scale, together with the survival times of flies 

 exposed to higher temperatures without food or water in dry 

 and in saturated air. The rather sudden change in the slope 

 of the curve in Fig. 1 suggests that the causes of death at high 



