The Origin of the Markings of Caterpillars. 271 



by no means be denied that the conditions of life 

 in young caterpillars are sometimes different to 

 those of the adults. It will, in fact, be shown later 

 on, that in certain cases the assumption of a new 

 guise at an advanced age actually depends upon 

 adaptation to new conditions of life ; but as a rule, 

 the external conditions remain very similar during 

 the development of the larva, as follows from the 

 fact that a change of food-plant never takes place. 1 

 We should therefore rather expect a complete 

 similarity of marking throughout the entire larval 

 period, instead of the great differences which we 

 actually observe. 



Different circumstances appear to me to show 

 that the markings of young larvae are only excep- 

 tionally due to a new adaptation, but that as a 

 rule they depend upon heredity. In the first 

 place, there is the fact that closely allied species, 

 exposed to precisely similar external conditions, as, 

 for instance, Chcerocampa Elpenor and Porcellus, 

 possess exactly the same markings when young, 

 these markings nevertheless appearing at different 

 stages of growth. Thus, the subdorsal line first 



1 [The larvae of many moths which feed on deciduous trees 

 during the autumn and hibernate, are stated to feed on low- 

 growing plants in the spring, before the buds of their food- 

 trees open. On the other hand, low-plant feeders, such as 

 Triphcena Fimbria, &c., are stated to sometimes feed at night 

 in early spring on the buds of trees. The habits and ontogeny 

 of these species are of special interest in connection with the 

 present researches, and are well worthy of investigation. R.M.] 



