1882.] 247 



meanwhile the segments of the body shorten, and their divisions 

 deepen ; the head becomes bent down close to the stem, while the 

 body is held away from it as far as the cincture allows — drawn tight 

 as it is into the deep division between the sixth and seventh segments, 

 so that only the head and tail are in contact with the stem ; at the 

 end of about a day and a half suddenly the head and front segments 

 are jerked backward 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 disclosed the 

 top of the head, then the iipper part of the face, and with a few nod- 

 ding motions the head is freed, and the skin slowly but easily slides 

 downwards from each side (the cincture causing not the least impedi- 

 ment), 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 hollow, when in another moment it is fitted upon the 

 cone 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 shrivelled 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 di- 

 verging 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 outline, 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 ex- 

 press my regret that I forgot to look for the connecting membrane 

 which was discovered in Pieris and Vanessa by Dr. Osborne, and 

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



The egg of Machaon 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 colour quickly turning green, and soon after tinged with violet- 

 brownish, gradually deepening to purplish, and faintly showing the 

 embryo through the shell, which in a day or two turns entirely 

 purplish-black, a process of change similar to that shown by a ripen- 

 ing black currant; the shell next assumes a- light pearly transparency, 



