Phylctic Parallelism in Mctamorphic Species. 413 



species as far as we know all live in precis* !\ 

 the same manner ; they all fly at twilight, 8 show- 

 ing a preference for the same flowers and very 

 often frequenting the same spots, so that in the 

 haunts of one species the others are almost always 

 to be met with, supposing them to occur in the 

 same locality. They conceal themselves by day 

 in similar places, and are attacked by similar 

 foes. 



It is quite different with the caterpillars. These, 

 even in the case of the most closely allied species, 

 live under different conditions, as appears from the 

 fact that they feed on different plants. The latter 

 can, however, produce changes both directly and 

 indirectly. The larvae may acquire adaptive 

 colours and markings, and these would vary in 

 accordance with the colour and structure of the 

 food-plant ; or they may become brightly coloured 

 as a sign of distastefulness in cases where they are 

 inedible. Then again the colour of the soil on 

 which the larvae live would act upon their colours 

 making these adaptive. Certain habits of the 

 caterpillars may also be dependent upon the 

 nature of their food-plants. Thus, e.g. Deilephila 

 Ifippophacs feeds only at night, and conceals 

 itself by day under moss and among the leaves at 

 the base of the food-plant ; but D. Euphorbia 

 could not acquire such a habit, because Euphorbia 



1 In some instances Deiltphila Lineata has also been seen 

 by day hovering over flowers. 



