376 Studies in the Theory of Descent. 



The question as to the relative ages of the 

 oblique stripes and the spot-marking does not 

 admit of a general answer. In some cases (C. 

 Elpenor and Porcellus] the oblique stripes disap- 

 pear when the ocelli reach complete development, 

 and we may therefore venture to conclude that in 

 these cases the former appeared earlier in the 

 phylogeny. But it is very probable that oblique 

 stripes arose independently at different periods, 

 just as longitudinal lines occur irregularly in quite 

 distinct families. It would be a great error if we 

 were to ascribe the possession of oblique stripes 

 solely to descent from a common ancestor. The 

 oblique markings found on certain species of 

 Macroglossa (M. Cory thus from India) have not 

 been inherited from a remote period, but have been 

 independently acquired by this or by some recent 

 ancestral species. They have nothing to do 

 genetically with the oblique stripes which occur in 

 some species of Chcerocampa (e.g. in C. Nessus, 

 from India), or with those of the species of 

 Smerinthus and Sphinx. They depend simply 

 on analogous adaptation (Seidlitz 6 ), i.e. on adapta- 

 tion to an analogous environment. 



The case is similar with the spot-markings. I 

 have already shown that under certain conditions 

 ring-spots may assume the exact appearance of 



6 " Die Darwin'sche Theorie. Elf Vorlesungen iiber die 

 Entstehung der Thiere und Pflanzen durch Naturziichtung." 

 2nded., Leipzig, 1875, p. 195. 



