300 MOTIONS OF INSECTS. 
its belly, which then becomes the convex part, touches 
the bottom. This occasions the cocoon to rise in the 
air to a height proportioned to the force of the blow. At 
first sight this faculty seems of no great use to an animal 
that is suspended in the air; but the winds may probably 
sometimes place it in a different and unsuitable position, 
and lodge it upon a leaf or twig: in this case it has it in its 
power to recover its natural station. Reaumur could 
not ascertain the fly that should legitimately come from 
this cocoon, for different cocoons gave different flies: 
whence it was evident that these ichneumons were infested 
by their own parasite*. This might be the case with 
that of the lady just mentioned. Perhaps, properly 
speaking, in this last instance the motions ought rather 
to be regarded as belonging to a larva; but as it had 
ceased feeding, and had inclosed itself in its cocoon, I_ 
consider it as belonging to the present head. 
You may probably here feel some curiosity to be in- 
formed how the numerous larvee that are buried in 
their pupa state, either in the heart of trees, under the 
earth, or in the waters, effect their escape from their va- 
rious prisons and become denizens of the air, especially 
as you are aware that each is shrowded in a winding 
sheet and cased in a coffin. In most, however, if you 
examine this coffin closely, you will see rEsuRGAM 
written upon it. What I mean is this, The pu- 
parium or case of the animal is furnished with certain 
acute points (admznicula) generally single, but in some in- 
stances forked, looking towards the anus, and usually 
placed upon transverse ridges on the back of the abdomen, 
but sometimes arming the sides or the margins of the 
@ Reaum. ii, 450. 
