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PHYSIOLOGICAL CENETICS 



patterns as scries of ripple-like lines between the main elements 

 of the pattern. They may he partly the expression of such 

 embryonic structures as the network of blood sinuses, as suspected 

 by Goldschmidt (1920(2). But thus far this type of secondary 



pattern has not yet been studied 

 genetically or experimentally. For a 

 genera] discussion, see Henke (1935). 

 One more case might be mentioned 

 in this connection which belongs 

 generally to the type represented by 

 the wing form of Drosophila. It is 

 known that many species of Papilio 

 have tails on their hind wings; it is 

 further known that in some species 

 only males have tails; and, further, 

 that in some of the polymorphic 

 species, females may have no tails, 

 short tails, or tails according to the 

 presence of different Mendelizing 

 genes (de Meijere, Fryer, etc.; see 

 Goldschmidt, 1931c/). A similar effect 

 may also be produced by action of 

 temperature (Standfuss) or shock 



Fig. 45.— Relation between (Poultoil). 1 Sueffert (1929a) showed 

 form and pigmentation of scales ' , 



in the flour moth. Eight types that the development of this wing 

 of pigmentation. IV and VI pattern — formation of tails — is such 



form the dark bands in wild , 



type; VIII forms the light that first a wing of normal contour is 

 pattern elements. The others formed, from which the tails are cut 



are found in the background. 



(From Kuehn, 1936, Naturwiss. out through a secondary process of 

 24, Fig. 5.) degeneration (Fig. 44). It is needless 



to discuss in detail the generalization that here a pattern-forming 

 process may be understood on the same lines as in our former 

 examples. 



In describing the case of the pattern of intersexual wings, we 

 repeatedly mentioned the fact that male areas have scales of the 

 typical form for males and, similarly, female areas, female scales 

 in type and arrangement (Fig. 46). Here we are facing another 

 important point. One and the same process — the spreading 



1 Poulton gave a different explanation of Van Someren's material; see 

 Goldschmidt, 193 Id, p. 475. 



