iU^ 



THE AlHEKi 



CT SC1E5K& 



PSYCHE. 



ORGAN OF THE CAMBRIDGE ENTOMOLOGICAL CLUB 



EDITED BY GEORGE DIMMOCK AND B. PICKMAN MANN. 



Vol II.] 



Cambridge, Mass., July, 1879. 



[No. 63. 



Pupation of the Nymphalidae. 



ABSTRACT. 



There is no more interesting phenomenon in insect transform- 

 ation than the withdrawal of the chrysahs from the shrunken lar- 

 val skin, and its firm attachment to the button of silk previously 

 spun by the larva, in those Rhopalocera which suspend themselves 

 perpendicularly during pupation. For a century and a half 

 Reaumur's account, namely, that the soft segments of the form- 

 ing chrysalis acted the part of legs by grasping the larval skin 

 between the sutures, has been accepted and generally copied. 

 Dr. J. A. Osborne, of Milford, England, first drew attention, 

 some two years ago (^Nature, v. 16, p. 502-503), to the fact that 

 there was a membrane concerned in the act, and Mr. W. EC- 

 Edwards, of Coalburgh, "West Virginia, corroborates Dr. Os- 

 borne's statement by observations on some of our American 

 species, recorded in the Canadian Entomologist of last De- 

 cember. 



In a paper recently presented to the Washington Philosophical 

 Society, at its meeting of June 7th, Prof. C. V. Riley records 

 the results of a number of observations on this subject, and thus 

 explains the philosophy of the act which has so long misled ob- 

 servers. His studies have been principally made with the larvae 

 of Vanessa antiopa, and we give the results as we have gath- 

 ered them from correspondence with him. 



The principal means by which the chrysalis holds on, and 

 rises at the critical moment, is a stout ligament, which is, vir- 

 tually, the shed intestinal canal ; not alone the lining, but the 



