The Origin of the Markings of Caterpillars. 273 



see precisely the same simple marking (the sub- 

 dorsal) line retained throughout all the stages in 

 two genera, whilst in the Smerinthince this line 

 vanishes at a very early stage, and in the Sphin- 

 gincz is only present in traces, we can give but 

 one explanation of these facts. We have here a 

 fragmentary series representing the phyletic de- 

 velopment 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 sub- 

 sequent development advanced, the older phyletic 

 stages would always be relegated to younger onto- 

 genetic stages, until finally they would be but 

 feebly represented even in the youngest stage (D. 

 Euphorbia), 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 onto- 

 geny 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 phylo- 

 geny. 



Considering this to be established, we have 

 next to deal with the uniformity of the develop- 



