CURIOUS FACTS ABOUT CHRYSALIDS. 1555 



eye is rough and coarse like tlie chrysalis skin generally, but this curved 

 ribbon is sinootii and thin, and regularly embossed, each gentle elevation 

 apparently corresponding to the centre of a facet of a compound eye 

 (86:22). Now it has been suggested that this belt is a window through 

 which the prisoner may look abroad ; what end this would serve is not ex- 

 plained ; nor have the structure, form, and position of the belt been taken 

 into consideration. No underlying structure, as far as I am aware, has 

 been foimd related to it alone ; and as an external covering of an eye its 

 structure is midway between that of the caterpillar and the perfect insect. 

 May it be a relic of the past, the external sign of what once was? Are 

 we to look upon this as one hint that the archaic butterfly in its transfor- 

 mations passed through an active pupal stage, like the lowest insects of 

 to-day, when its limbs were unsheathed, its appetite unal)ated, and its daily 

 necessities required the use of a compound eye, such as would result 

 from the multiplication and conglomeration of simple eyes within the 

 normal ocellar field of the larva? This, it is true, is merely speculation ; 

 but whatever explanation of the structure of this glassy band is given 

 must account for its form and its relation to the larval row of tubercles. 



There is another peculiarity in the head of certain chrysalds which de- 

 mands our attention and an explanation of its cause, since it is found in 

 some groups and not in others. On either side of the front of the head 

 there is often a roughened angulate or conical projection, bearing no rela- 

 tion whatever to the parts beneath, but looking like a pair of clumsy horns 

 or ears projecting forward ; other chrysalids have the front extremity pro- 

 longed in the middle, while the sides of the head are quite smooth and 

 regular ; others again have the same smooth and bluntly rounded head 

 which generally characterizes the pupa of moths. Since these projections 

 are mere extensions of the pellicle and quite hollow, it might be pre- 

 sumed that they indicated some variation in the life of the chrysalis ; and 

 such at least generally is indeed the fact. Many chrysalids are protected 

 by some sort of a cocoon ; and these have perfectly smooth and rounded 

 heads ; so, too, have those which, though exposed, are girt immovably to 

 the object they have chosen as their support. Other chrysalids are at- 

 tached by the tail and loosely bound about the middle by a girth which 

 allows the body to sway from side to side ; while still others hang freely 

 by their hinder extremity. In these two latter cases the chrysalids may be 

 blown hither and thither by every breeze and are liable to injury from 

 neighboring objects ; as in all cases the tail is fastened, their point of 

 greatest motion is of course the head, and this, therefore, is guarded by 

 projecting roughnesses. In those which hang freely there are some excep- 

 tions to this rule, as in the case especially with the Satyrids, but even here 

 some angulations or little conical tubercles may be discovered ; and, be- 

 sides, the chrysalis stage of such species is invariably passed in midsum- 



