75 



spores bound by a membrane. Thus, meiosis occurs at the 

 age limit for thermal inhibition of MB spore development. 

 The high variability of inhibition among pupae in this age 

 group simply reflects the slight variability in age of indi- 

 viduals and the degree to which MB sporulation had advanced 

 at the time of temperature change. Once sporogony is under 

 way (meiosis has occurred?), it apparently cannot be stopped 

 by temperatures at least as low as 20 C or as high as 32 C. 



