148 Mr. Poulton's notes in 1885 upon 



upon the underside there are extremely minute hairs 

 borne by exceedingly small traces of dots, exactly as in 

 S. ligustri in the last stage. Again, the caudal horn is 

 well known to be rough, and this condition is caused by 

 the persistence of true shagreen dots upon it, many of 

 which bear simple hairs. 



Compg,ring the larva with that of S. lifjustri in the same 

 stage, A. atropos exhibits phyletically older features in 

 the persistence of normal shagreen dots upon the horn, 

 and of (much modified) dots upon the dorsal surface, and 

 in the persistence of the "eighth stripe" (border). On 

 the other hand, it is phyletically younger in the extreme 

 development of the coloured borders, and probably in 

 the fading away of the oblique stripes. 



This last point adds another stage to the long history 

 of the oblique stripes and their borders in Sphingidce. 

 The history may be recapitulated as follows : — 



1. A hairy larva with greenish or yellowish ground 



colour ; the hairs springing from light (white or 

 yellow) tubercles. 



2. The hairs become inconsj)icuous and the tubercles 



more distinct. 



3. The tubercles become especially enlarged and approxi- 



mated along the lines of the oblique stripes, thus 

 forming the first indications of this system of 

 marking. 



4. The light colour spreads from the base of each 



tubercle, and the adjacent areas coalesce, forming 

 a continuous stripe. 



5. The tubercles disappear from the ground colour along 



the anterior edge of each stripe, thus producing a 

 relatively dark border. 



6. The border is rendered more distinct by a deepening 



in the tint of the ground colour. 



7. The border becomes a conspicuous feature in the 



oblique line system, gaining a distinct and generally 

 bright tint, a modification or replacement of the 

 ground colour. 



8. The original oblique stripes fade away until they 



are hardly recognisable, while the bright borders 

 become highly developed, and almost entirely 

 represent the whole system. 



