176 Studies in the Theory of Descent. 



that we have here a residue of the same marking 

 which is found completely developed in many other 

 Sphinx-larvae, and indeed in the young stages of 

 this same species. The mode of describing cater- 

 pillars hitherto in vogue is in fact unscientific ; the 

 descriptions have not been made with a view to 

 determining the morphology of the larvae, but 

 simply to meet the practical want of being able to 

 readily identify any species that may be found : 

 even for this purpose, however, it would have 

 been better to have employed a more precise 

 mode of description. 



