( cxvi ) 



is nearly in the same line with that of the thoracic. Suspension 

 by the posterior apical hooks and the assumption of a form 

 in which the long axis of the body is nearly in one line, is 

 very ancient, dating back to the common ancestor of a number 

 of closely-related species. For a countless number of genera- 

 tions the soft and yielding Vanessid pupa has been subjected 

 to the strain of gravity and has responded by the production 

 of a definite shape, viz. one in which the long axis is parallel 

 with the line of force. And yet not a trace of any hereditary 

 effect is manifest. Remove the strain and the individual is 

 free, unbiassed by the forces exerted upon unnumbered 

 ancestors, to assume an entirely different shape. 



Vanessid pupae alone, so far as I am aware, have been 

 studied from this point of view. Figures of other suspended 

 Nymphaline pupse however indicate that all do not yield 

 equally to the strain, although I believe that all are to some 

 extent affected. The pupae of the Argynnidse contrast in an 

 interesting manner with those of the Vanessidae in this respect. 

 The strongly-curved pupa of Aryynnis aglaia figured by W. 

 Buckler * was probably supported wholly or in part by a leaf, 

 as is suggested not only by the shape but the plane of the 

 surface of attachment, as shown in the figure, and to some 

 extent by the description. 



Variable Protective Resemblance in Insects. — The power 

 which it is now known that many larvae and pupae possess of 

 changing their colour into correspondence with the tints of 

 each one of several possible environments has been thought 

 to favour the Lamarckian interpretation of the origin of 

 variation. Thus the late George J. Romanes said of the 

 evidence which had been brought forward to prove the power 

 in question : — " It has always appeared to me that the experi- 

 ments themselves are among the most valuable which have 

 hitherto been made regarding the causes of variation," f an 

 opinion due, as the writer states, to his acceptance of the 

 " Lamarckian conception." 



On the other hand, I have never doubted that the results 

 are in the nature of a climax rather than a foundation, that 



* Ray Society, "Larva; of British Butterflies and Moths," vol. i, Plate 

 X, fig. 3&, 1886. t " Nature," vol. xxxviii, 1888, p. 364. 



