390 THE AMERICAN NATURALIST [Vol. LVI 



one of the Studies (27), a shorter abscissal interval has 

 been used in the grouping. The figures for Quintuple 

 stock flies, and for an inbred Quintuple line (No. 405) 

 are given separately. 



ffilBUTlONS (?^) OF VENTILAT] 



Quintuple Stock and Line i 



) Control Flies 



The calculated constants from the dx distributions are 

 given in Table IV. 



TABLE IV 



-14.66 ±4.29 



