THE MUTATED OENE 



-'7 



1 1 n 'i it (if not \ isibly, .-it Least in the form of spatial determination) 

 before the process that results in scalloping begins. Actual 

 development proves that this expectation is literally true. In the 

 scalloped types, almost up to the type of the allele snipped, 

 development of the wing proceeds perfectly normally until 

 pupation, when the wing disk is protruded (evaginated) and 

 expanded to the size and shape <»t" the pupal wing, which secretes 

 its chitinous sheath (Fig. 9). Only then a degeneration, <>r 



t 



I 



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Fio. 9. Three stages From poatpupal development of a vg og** whig in 1 l 

 phila. The wing ia normal at the time of pupation. (From Ooldachmidt, 1937 

 of ' alif I , i>l. 15.) 



lysis, of tin- tissue sets in at the point- of later scalloping, and 

 these pathological area- of the \\in«j spread are gradually resorbed 

 to form the nick- and notches (Fig. 9). This resorbing process 

 end- when the detail- of wing -tincture are being perfected. 

 It i- a general rule that as the process of degeneration sets in 

 earlier and earlier, a more and more extreme scalloping results. 

 In the higher made-, ,'., ., the phenotypes ragged, antlered, -trap, 

 vestigial, and No-wihg, the process actually begins in the imaginal 



disk, and at the time of pupation part- of the wing area have 



