The Origin of the Markings of Caterpillars. 279 



The remarkable phenomenon of the backward 

 transference of newly acquired characters may 

 therefore be formulated as follows : Changes 

 which have arisen in the later ontogenetic stages 

 have a tendency to be transferred back to the 

 younger stages in the course of phyletic develop- 

 ment. 



The facts of development already recorded 

 furnish numerous proofs that this transference 

 occurs gradually, and step by step, taking the 

 same course as that which led to the first esta- 

 blishment of the new character in the final onto- 

 genetic stage. 



Did this law not obtain, the ontogeny would 

 lose much of the interest which it now possesses 

 for us. It would then be no longer possible, 

 from the ontogenetic course of development of an 

 organ or of a character, to draw a conclusion as to 

 its phylogeny. If, for instance, the eye-spots of 

 the Chcerocampa larvse, which must have been 

 acquired at a late age, were transferred back to 

 the younger ontogenetic stages in the course of 

 phyletic development, as eye-spots already per- 

 fected, and not showing their rudimentary com- 

 mencement as indentations of the subdorsal line, 

 the phenomenon would then give us no informa- 

 tion as to the manner of their formation. 



It is well known to all who have studied the 

 developmental history of any group of animals, 

 that no organ, or no character, however complex, 



