REVERSAL OF FUNCTION IN OLIGARCES. 



TABLE I. 



RKVERSAL OF F> OF PUPA-LARVAE FOLLOWING THE RELEASE OK YOUNG 



FROM CROWDING. 



Culture M 187 was made up of larvae of the F i<> ^cm-ration i.t 

 .1 strain maintained in the laboratory, cultures M 222, M 223, 

 and M 224 represent the F 12 generation. This Mrain \vas 

 -ill. !< i tl to crowding with the consequent production >t pupa 

 lar\.r in five of the ten generations. In no cases in which pupa- 

 lar\.i- \\rre not released from crowding did reversal "f func- 

 t ii'ii ncciir. 



In \ i-\v of the results of this study the conclusion sn-nis in ! 

 \\cll futindi-d that a reversal of the normal function <>l pupa- 

 la! \ a- to that of p;ixlogenetic larvae can be obtainc-(l at will in the 

 lalior.it. iry li>- reversing the conditions under which pupa-lar\a- 

 aro>c. Thi> reversal has been obtained in tin- pa-sent instance 

 l'\ nK.i-ini; pupa-larva? from crowding. 



\r\\ly 1'orn and ver>' young pupa-larvae are mon- likc-K to ^i\ c 

 r\ iiliiu of tin- influence of changed external condition- than are 

 older pupa-larva-. This probably indicates that a change, 

 P'--ilily ivdiM tion division, occurs in the eggs of the pupa-lar\,r 

 \\hrn tlu- lar\-a i- -till young. Before this chan^i- ha- occurred 

 tlu- C-L;S a a- still capable of pacdogenetic development if external 

 conditions are suitable. The progressive development of 

 embryos within such a pupa-larva probably inhibits the normal 



