LEPIDOPTERA. 



159 



hardly bends the joints of its body. The outside skin of the 

 chrysalis appears to be cartilaginous ; it is generally smooth, although 

 some species have hairs scattered over their bodies. 



We distinguish in chrysalides two opposite sides. The one is 

 the insect's back, the other its under side. On the upper part of the 

 latter (Fig. 124) we perceive various raised portions, formed and 

 arranged like the bands round the heads of mummies ; the back is 

 plain and rounded in a great number of pupae ; but a great many 

 others have on the upper part, along the edges which separate the two 



Fig. 124. 

 A conical pupa. 



Fig. 125. Fig. 126. 



Pupa having angular projections. Angular pupa of a Butterfly. 



sides, little humps, eminences broader than they are thick, ending in 

 a sharp point (Fig. 125). 



The head of the angular pupae terminates sometimes in two 

 angular parts, which diverge from each other like two horns 

 (Fig. 126). In some other cases they are curved into the form of a 

 crescent. These appendages sometimes give to the pupa the appear- 

 ance of a mask, especially as an eminence placed on the middle of 

 the back is rather like a nose, and the small cavities may represent 

 the eyes (Fig. 125). 



The colours of angular pupae attract our attention. Some are 

 superbly tinted ; they appear to be wrapped in silk and gold. Others 

 have only spots of gold and silver on their belly or their back. All, 

 however, have not this remarkable splendour, not these metallic spots. 

 Some are green, yellow, and spotted with gold. Generally they are 

 brown. Re'aumur has shown that this golden colour is not due, as 

 was thought for a long while, to colouring matter, but to a little 

 whitish membrane, placed under the skin, which reflects the light 

 through the thin outer pellicle, in such a manner as to produce the 



