1694 



THE BUTTERFLIES OF NEW ENGLAND. 



tween the edges of some of the abdominal segments, holding on by which 

 the tail was withdrawn, then elongated and the cremaster thrust into the 

 mass of silk prepared for it. The schematic figures, PI. 87, fig. 20 a-c 

 indicate this view of pupation. 



This is true to a certain extent with some butterflies ; that is, these ac- 

 tions take place, but they are not true of others and are insufficient to 

 effect the end in all, as the seizure of the skin when it occurs is largely 

 accidental and before it is seized the skin has so far retreated toward the tip 

 of the body that the chrysalis would fall from its enclosure but for other 

 important connections between the larval skin and the chrysalis. 



B. 

 Fig 3. 



Fig. i. 



For in the ecdysis the lining membranes of the alimentary canal and the 

 respiratory vessels are pulled out and cast off with the old integument, and 

 that of the intestinal tube now plays an important part, serving as a liga- 

 ment to unite the two so long as union is necessary ; and in addition there 

 is secreted between the old and new membranes at the extremity of the 

 body a mucous, which, in the parting of the two, envelopes the rectal 



Fig. 1. Schematic figure of the changes in 

 Anosia plexippus. A, soou after suspension ; 



B, a few hours Liter, the needle separating 

 the forming membrane from the sustalners ; 



C, just before larval skin splits, with retain- 

 ing membrane loosened and showing Its con- 

 nection with both larval and pupal rectum. 

 In all the figures the forming chrysalis Is 

 shaded, and the Intervening space between it 

 and larval skin is dotted. 



Pig. 2. Shrunken larval skin of Euvanessa 

 antiopa, cut open from the back. 

 Fig. 3. A, Chrysalis of Xanthldia nlcippe ; 



B, hinder end of that of Anaea audria; C, of 

 that of Anosia plexippus. 



Fig. 4. Tall of chrysiilis of Euvanessa anti- 

 opa, just before withdrawal from larval skin. 



The common lettering is as follows : ap, 

 anal plate; c, cremaster; chp, cremastral hook 

 pad; ffcr, dorsal cremastral ridge; h, hillock 

 or pad of silk ; hi, hooks of hind legs ; Ir, 

 larval rectum; mr, retaining membrane: pr 

 pupal rectum; W, rectal ligament; rp, rectal 

 plate ; s, sustalners ; sr, sustaining ridges ; tl, 

 tracheal ligament; vcr, ventral cremastral 

 hooks. 



