STATES OF INSECTS. (Pupa.) 279 
coon, converge also to a point, and form a sort of cone 
exactly like the closed peristome of a moss ; or, to use a 
more humble though not less apt illustration, like the 
wires of certain mousetraps*. In this dome not the 
slightest opening is left, and from its arched structure it 
is impenetrable to the most violent efforts of any ma- 
rauders from without; whilst it yields to the slightest 
pressure from within, and allows the egress of the moth 
with the utmost facility. When she has passed through 
it, the elastic threads resume their former position, and 
the empty cocoon presents just the same appearance as 
one still inhabited. Rdsel relates with amusing naivété 
how this circumstance puzzled him the first time he wit- 
nessed it: he could scarcely help thinking that there was 
something supernatural in the appearance of one of these 
fine moths in a box in which he had put a cocoon of 
this kind, but in which he could not discover the slight- 
est appearance of any insect having escaped from it, until 
he slit it longitudinally>®. But from an observation of 
Meinecken, it appears that these converging threads serve 
a double purpose; being necessary to compress the ab- 
domen of the moth as it emerges from the cocoon, which 
forces the fluids to enter the nervures of the wings, and 
give them their proper expansion. For he found, that 
when the pupa is taken out of the cocoon, the moth is 
disclosed at the proper time, but remains always crippled 
in its wings; which never expand properly, unless the 
abdomen be compressed with the finger and thumb, so 
as to imitate the natural operation ®. 
“ Prate XVII. Fic. 5. N.B. Sepp’s figure represents the exterior 
funnel; and this, which exhibits the cocoon divided longitudinally, 
the interior one, or dome. 
Ros. I. iv. 31. © Naturf. viii. 133. 
