But the strongest, and, as it appears to me, the most convincing proof of the purely phyletic significance of the young larval markings, is to be found in the striking regularity with which these are developed in a similar manner in all allied species, howsoever different may be their external conditions of life. In all the species of the _Chærocampa_ group (the genera _Chærocampa_ and _Deilephila_) the marking--no matter how different this may be in later stages--arises from the simple subdorsal line. This occurs even in species which live on the most diverse plants, and in which the markings can be of no biological importance as long as the larvæ are so small as to be only visible through a lens, and where there can be no possible imitation of leaf-stalks or veins, the leaves and caterpillars being so very distinct.
Moreover, when in the _Macroglossinæ_ (the genera _Macroglossa_, _Pterogon_, and _Thyreus_) we see precisely the same simple marking (the subdorsal) line retained throughout all the stages in two genera, whilst in the _Smerinthinæ_ this line vanishes at a very early stage, and in the _Sphinginæ_ is only present in traces, we can give but one explanation of these facts. We have here a fragmentary series representing the phyletic development of the Sphinx-markings, which latter have arisen from one original plan--the simple subdorsal line--and have then undergone further development in various directions. As this subsequent development advanced, the older phyletic stages would always be relegated to younger ontogenetic stages, until finally they would be but feebly represented even in the youngest stage (_D. Euphorbiæ_), or else entirely eliminated (most of the species of the genus _Sphinx_). I believe that no other sufficient explanation of these facts can be adduced. Granting that the correctness of the above views can no longer be doubted, we may now take up the certain position that the ontogeny of larval markings reveals their phylogeny, more or less completely, according to the number of phyletic stages omitted, or, in some exceptional cases, falsified. In other words, the ontogeny of larval markings is a more or less condensed and occasionally falsified recapitulation of the phylogeny.