The Origin of the Markings of Caterpillars. 373 



of marking the oblique stripes has been de- 

 veloped out of the first. If these had arisen by 

 the transformation of the longitudinal stripes, the 

 two forms could not exist side by side. This is 

 the case, however, both in certain species in the 

 adult state (Calymnia Panopus*), as well as in 

 others during their young stages (most beautifully 

 seen in Smerinthus Populi, Fig. 56). Various facts 

 tend to show that the oblique stripes appeared in 

 the phyletic development later than the longi- 

 tudinal lines. In the first place they appear later 

 than the latter in the ontogeny of certain species. 

 This is the case with Charocdmpa Elpenor and 

 Porcellus, in which, however, they certainly do 

 not reach a high state of development. Then 

 again, the longitudinal lines disappear completely 

 in the course of the ontogeny, whilst the oblique 

 stripes alone maintain their ground. Thus, the 

 subdorsal line vanishes at a very early stage, with 

 the exception of a small residue, 4 in all native 

 species of Smerinthus. I have already attempted 

 to show that new characters are only acquired in 

 the last stage, and that if still newer ones are then 

 added, the former disappear from the last stage, 

 and are transferred back to a younger one. 

 Characters vanish therefore from a stage in the 

 same order as they were acquired. 



2 Cat. Lep. East India Co., PL VIII. 



4 Such a residue is distinctly visible in S. Ocellatus ; see 

 Fig. 70, PL VII. 



