88 



and a half suddenly the head and front segments are jerked back- 

 ward four or five times in succession ; next the belly is brought 

 close to the stem and the head held up, and then in about five 

 minutes the skin splits open behind the head on the top of the 

 back, and the pupal thorax appears bulging out; presently is dis- 

 closed the top of the head, then the upper part of the face, and with 

 a few nodding motions the head is freed, and the skin slowly but 

 easily slides downwards from each side (the cincture causing not 

 the least impediment), and as it goes drags away like little threads 

 the linings of the spiracles ; presently from out of the collapsing 

 skin is disclosed the tip of the tail, and there is just time allowed 

 for the observer to see that it is quite holloiv, when in another 

 moment it is fitted upon the co7ie of silk, and strongly pressed 

 down, and with a repeated half screwing motion the attachment is 

 made complete ; meanwhile the moisture which exudes from the 

 pupal surface has surrounded and fairly embedded the cincture 

 at its line of contact with the back ; the old shriveled skin now 

 rests in a heap between the lower part of the abdomen and the 

 stem, but is presently, by a slight twisting movement on the part 

 of the pupa, caused to drop off; the head and thorax gradually 

 develop themselves, the former into two largish blunt diverging 

 processes, the latter into a central bluntly projecting eminence, 

 with another on either side; the larval tubercles remain as small 

 blunt conical protuberances, the wing-covers form an angular out- 

 line, and the back becomes dull and rough; just four minutes 

 elapse from the bursting of the larval skin to the full disclosure. 

 (Here I must express my regret that I forgot to look for the con- 

 necting membrane which was discovered in Pieris and Vanessa by 

 Dr. Osborne, and described in vol. xv, p. 59, of this Magazine.) 



The t^^ of MacJiaon is globular, having a depression at the 

 base in contact with the leaflet on which it adheres; it is of a 

 good size and with apparently smooth surface, and when first laid 

 is of a greenish-yellow color, quickly turning green, and soon after 

 tinged with violet-brownish, gradually deepening to purplish, and 

 faintly showing the embyro through the shell, which in a day or 

 two turns entirely purplish-black, a process of change similar to 

 that shown by a ripening black currant ; the shell next assumes 

 a light pearly transparency, and the dark embryonic larva coiled 

 round within is plainly visible, and in a few hours hatches. 



The newly-hatched larva is 3 mm. long, stoutish, with shining 

 black head and black velvety body with dark green segmental di- 

 visions, and conspicuously marked with a patch of creamy-white on 

 the seventh and eighth segments ; the pale pinkish tubercles, in 

 some instances yellowish, rather bristly, are in two rows down either 

 side, and in about eight hours turn dark drab, and in a day or so 

 blackish like the third row beneath, except those on the white 

 patch, which remain white. 



After the first moult, in three days the length is 8 or 9 mm., 



