96 LEPIDOPTERA. 



often edged inside by a purple stripe, which proceeds 

 obliquely to the top of the hump on the fourth segment ; 

 where they diverge again obliquely to the seventh and eighth 

 segments, upon which, in some specimens, they descend to 

 near the spiracles, but in others, quite down to the prolegs ; 

 thence rapidly returning toward the dorsal region, and 

 proceeding quite to the anal fork. The whole surface of the 

 back above these two white stripes is purple, or brown dusted 

 with purple, or with lilac, or even white ; it forms a most 

 striking dorsal blotch, and has been compared to a saddle, 

 having a most conspicuous crupper. The apex of the hump 

 of the fourth segment is dull crimson ; the spiracles white 

 edged with black ; the legs brown ringed with yellow ; anal 

 tails whitish, greenish, or purplish, with brownish-black 

 rough tips and roughnesses or incrustations ; between them 

 are two black points. 



A formidable and alarming looking creature, as it sits with 

 head drawn back, the black spots like two great eyes, the 

 conspicuous hump, the contrasting purple, white, and green 

 colour, and the two divergent tails, upraised and threatening. 

 When young the angles of the second segment are sharper, 

 almost like horns, the hump on the fourth segment even 

 more conspicuous, the anal tails longer, and their contained 

 whips long and much more easily excited to protrusion, 



July, August, and sometimes September, more especially 

 upon poplar, but also upon aspen, willow, and sallow ; always 

 sitting on the upper side of a leaf, most conspicuously, and 

 feeding vigorously in the sunshine ; also feeding much at 

 night. The large leaves of the Canadian poplar {Po'pulus 

 halsamifera) in gardens in the outskirts of towns seem to be 

 much favoured. 



Pupa rather soft, stout, blunt, with prominent eyes and 

 well-defined antenna-cases ; incisions deeply cleft ; anal 

 extremity with numerous small warts ; purplish-brown with 

 darker wing-cases. Enclosed in a hard shell-like cocoon, 



