i66 



THE AMERICAN ENTOMOLOGIST. 



abundantly proved, at least ten or twelve 

 times the weight of the chn salis : while it 

 will support, if held by the larval skin, 

 several times the weight of the chrysalis, 

 before separating therefrom. Experimen- 



and always intimately connected with and 

 forming but a branch of the rectal ligament. 

 When extended from its attachments, as 

 when the chrj-salis rises to the silk, this 

 membrane dries, and in the cast-oflf lar\al 



A, chrysalis erf Terias : B. posterior end of chrysalis oi Pafkia : C, do. of Danais : E, one of 

 the ststaiaets of Terias^ greatly enlarged to show its hooked nature ; all the parts of sabjoint let- 

 med to cone^iOQd with the same parts in F^. 68 vafter Rileyt. 



tal proof is easily obtained by pinning the 

 larval skin, which has been flayed from the 

 chrysalis, to a small piece of cork and then, 

 while grasping the chrysalis as indicated, 

 sticking additional pins in the cork, until 

 the increasing weight breaks the ligament. 



skin retains, more or less perfectly, the 

 stretched form. If the mucous membrane 

 of the lar\-a was thick and strong, as in 

 Vanessa, the dried membrane will be broad, 

 with two indentations where it was held by 

 the retainers; if more delicate, as in Danais, 



Tiz. TO.^ 



PCPATIOX OF BuTTEEFUES: — a, attachment of ^zx^^oi Danaix archippus : p.Ao.ol Paphia glyce-riufii : 

 B, idea] larrasoon after so^teasion ; d,do.^ fev hoars later, the needle fn) separating the forming membrane from 

 the snstainers ; e, do. jast before flitting of larral skinv with retaining membrane loosened &om the sustainers . 

 and shoving its cosnection both with the larval and pupal rectum, la ail the figures the joints of body are 

 Bnmfaered ; the forming chrysalis is shaded in transrerse Uues ; the interrenin? space between it and larval skin 

 is dotted ; 4 is the hillock of silk ; Jk/, hooks of hind legs ; a/, aaal plate ; /r. Urval rectum ; /r, pupal rectum ; 

 mr, retaining membrane ; r, cxemaster; t, sostainers (after Riley). 



In brief, the retaining membrane is that 

 part of the inner larval skin surrounding 

 the prolegs, drawn down by the sustainers, 



Paphia, or Apatura, the dried membrane 

 is more forked, showing how the retainers 

 have acted upon its elasticitj-. In every 



