A marking is therefore produced in this case by a purely innate law of growth--by the superposition of two ancient characters now rudimentary. Many other unimportant details of marking must be regarded as having been produced in a similar manner, although it may not be possible to prove this with respect to every minute spot and stripe. The majority of “subordinate markings” depend on the commingling of inherited, but now meaningless, characters with newly acquired ones. It would be quite erroneous to attribute to natural selection only those characters which can be demonstrated to still possess a biological value in the species possessing them. They may be equally due to heredity. Thus, it is quite possible that the faint and inconspicuous ring-spots of _Deilephila Vespertilio_ are now valueless to the life of the species--they may be derived from an ancestral form, and have not been eliminated by natural selection simply because they are harmless. I only mention this as a hypothetical case. In the case of markings of the second class, _i.e._ oblique stripes, a transference to later phyletic stages can be demonstrated, although the stripes thereby lose their original biological value. Thus, the _Chærocampa_ larvæ, when they were green throughout their whole life and adapted to the leaves, appear to have all possessed light oblique stripes in imitation of the leaf-ribs. All the species of the older type of colouring and marking, such as _Chærocampa Syriaca_ (Fig. 29) and _Darapsa Chœrilus_ (Fig. 34), and also the light green young forms of _C. Elpenor_ (Fig. 20), and _Porcellus_ (Figs. 25 and 26), show these oblique stripes. In these last species the foliage imitation is abandoned at a later stage, and a dark brown, or blackish-brown, ground-colour acquired. Nevertheless the oblique stripes do not disappear, but show themselves--in the fourth stage especially, and sometimes in the fifth--as distinct dirty yellow stripes, although not so sharply defined as in the earlier stages. These persistent stripes, in accordance with their small biological value, are very variable, since they are only useful in so far as they help to break up the large surface presented by the caterpillar, and are of no value as imitations of surrounding objects.