Phylctic Parallelism in Metamorphic Species. 455 



the roughness or smoothness of the skin (compare 

 ;. 51, PI. VI. with Figs. 43 and 44, PI. V.), the 

 moths cannot be distinguished with certainty. As 

 has already been stated, the imago of the rare D. 

 Nicaa is for this reason wanting in most collec- 

 tions ; it cannot be detected whether a specimen 

 is genuine, i. e. whether it may not perhaps be a 

 somewhat large example of D. Euphorbia. 



An especially striking instance of incongruence 

 is offered by the two species of Charocampa most 

 common with us, viz., Elpenor and Porcellus, the 

 large and small Elephant Hawk-moths. The 

 larvae are so similar, even in the smallest details of 

 marking, that they could scarcely be identified 

 with certainty were it not that one species 

 (Elpenor) is considerably larger and possesses a 

 less curved caudal horn than the other. The 

 moths of these two specie? much resemble one 

 another in their dull green and red colours, but 

 differ in the arrangement of these colours, i. e. in 

 marking, and also in the form of their wings, to 

 such an extent that Porcellus has been referred to 

 the genus Pergesa I8 of Walker. If systemy, as is 

 admitted on many sides, has only to indicate the 

 morphological relationship, this author is not to 

 blame but in this case a special larval classifi- 

 cation must likewise be admitted, in a manner 

 somewhat similar to that at present adopted 

 provisionally in text-books of zoology for the 

 u Cat. BriL Mus. 



