Phyletic Parallelism in Mcliimorphic Species. 409 



But in granting this, we decidedly refute the 

 statement that constancy and variability are in- 

 herent properties of certain forms of marking. 



This reasoning is based on the simple fact that 

 a given type of marking comprises both species of 

 great constancy and of (relatively) great variability. 



Thus, the fore-wings of Sphinx Ligustri and 

 6*. Convolvuli are extremely constant, whilst the 

 very similarly marked Anceryx (Hylouus) Pin- 

 astri is exceedingly variable. Similarly Deile- 

 phila Euphorbia is known by its great variability 

 of colouring and marking, whilst D. Galii, which 

 resembles this species so closely as to be some- 

 times confounded with it, possesses a high degree 

 of constancy, and further, the Corsican and Sar- 

 dinian D. Dahlii is very variable. Among the 

 family Arctiidce, CallimorpJia Hera and the Alpine 

 Arctia Flavia are cases of constancy, whilst A. 

 Caja, which is so similar to the last species, is so 

 generally variable that two perfectly identical 

 specimens can scarcely be found together. 



The same can be shown to hold good for the 

 markings of caterpillars. Thus, the larva of D. 

 Dahlii shows very considerable variability, whilst 

 that of D. Galii is very constant in marking (dis- 

 regarding the ground-colour). So also the larva 

 of Vanessa Urtica is very variable and that of V. 

 Antiopa very constant, &c. 



The great differences with respect to constancy 

 or variability which are displayed by the different 



