The Origin of the Markings of Caterpillars. 2 1 7 



of the other illustrations. The ground-colour of 

 the caterpillar is green ; the subdorsal yellow, 

 bordered with black, slightly curved, arched lines, 

 which nowhere interrupt its continuity. This 

 North American species appears therefore to be 

 an older form than our Livornica. 



DEILEPHILA ZYGOPHYLLI, OCHSENHEIMER. 



This species, which is the next allied form to 

 D. Lineata, is an inhabitant of Southern Russia. 

 I have seen four specimens of the caterpillar in 

 Dr. Staudinger's collection, three of which are 

 certainly in the last ontogenetic stage. The 

 ground-colour appears ash-grey, ash-brown, or 

 blackish with whitish granulations. A broad 

 white subdorsal line extends to the base of the 

 black caudal horn, this line in one specimen 

 appearing at first sight not to possess a trace of 

 spot rudiments (Fig. 50). On closer investiga- 

 tion, however, there could be observed, in the 

 same position where the ring-spots stand in the 

 other species of Deilephila, small black crescents 

 above and below the subdorsal line. In other 

 specimens the white subdorsal line had also 

 become expanded in these positions into distinct 

 spots ; indeed, in one individual light white 

 mirror-spots, bordered above and below by black 

 crescents, stood on the subdorsal line (Fig. 50 A). 



It is thus in this distinguishing character that 

 the caterpillar is extremely variable, and we may 



