38S 



Fig. 14B. Chart of equal-velocity lines tor the pupal stage. These veloci- 

 ties were multiplied by 1.07 to correct for variability (see Table I). The 

 curves pass through combinations of temperature and humidity which give 

 the same velocity of development. The curves in Pig. 13 may be likened to 

 cross sections of a hill of which these are contour lines. 



