The Origin of the Markings of Caterpillars. 365 



this is certainly not the case with eye- and ring- 

 spots. The most light is thrown upon this question 

 by the latter, because a species which has remained 

 at the initial stage of the formation of ring-spots 

 here presents itself for examination, viz. Deilephila 

 Hippophaes. 



I have attempted to show that the orange-red 

 spots, which, as a rule, adorn only the eleventh 

 segment, enhance the adaptive colouring of this 

 caterpillar by their resemblance to the berries of the 

 sea-buckthorn, whilst the general surface resembles 

 the leaves in colour. If this be admitted, the 

 origination of these spots by natural selection 

 offers no difficulty, since a smaller spot, or one of 

 a fainter red, must also be of some use to its 

 possessor. 



This case is of importance, as showing that a 

 " change of function " may occur in markings, just 

 as it does in certain organs among the most 

 diverse species of animals, in the course of phyletic 

 development. The spots which in Hippophaes 

 are imitations of red berries, in species which have 

 further advanced phyletically play quite another 

 part they serve as means of alarm, or signals of 

 distastefulness. 



It appears to me very improbable, however, 

 that the perfect ocelli of the Cktzrocampa-lzrvaz 

 have also undergone such a "functional change" 

 (Dohrn). I rather believe that the first rudiments 

 of these markings produced the same effect as that 



