29'2 STATES Ot INSECTS. 



If the excluded insect be a bee or a fly, its whole skin is 

 white and looks fleshy, and quite unlike the coloured 

 hairy crust which it will turn to in an hour or two ; and 

 the wings, instead of being a thin, transparent, expand- 

 ed film, are contracted into a thick, opaque, wrinkled 



mass. 



These symptoms of debility and imperfection, how- 

 ever, in most cases speedily vanish. The insect, fixing 

 itself on the spoils of the pupa, or some other convenient 

 neighbouring support, first stretches out one organ, and 

 then another : the moisture of its skin evaporates, the 

 texture becomes firm, the colours come forth in all their 

 beauty ; the hairs and scales assume their natural posi- 

 tion ; and the wings expanding, extend often to five or 

 six times their former size — exhibiting, as if by magic, 

 either the thin transparent membranes of the bee or fly, 

 or the painted and scaly films of the butterfly or moth, 

 or the coloured shells of the beetle. The proceedings 

 here described I witnessed very recently with regard to 

 a very interesting and beautiful butterfly, the only one of 

 its description that Britain has yet been ascertained to 

 produce — I mean Pajrilio Machaon. The pupa of this 

 being brought to me by a friend early in May this year 

 (1822), on the sixteenth of that month I had the pleasure 

 to see it leave its puparium. With great care I placed it 

 upon my arm, where it kept pacing about for the space of 

 more than an hour ; when all its parts appearing conso- 

 lidated and developed, and the animal perfect in beauty, 

 I secured it, though not without great reluctance, for my 

 cabinet — it being the only living specimen of this fine fly 

 I had ever seen. To observe how gradual, and yet how 

 rapid, was the development of the parts and organs 3 and 



