THE LIBELLULA. 35e 
the intestine and admits a quantity of water. This, of course, 
contains air mechanically suspended, which is taken up the 
trachezee just mentioned. Curiously enough, these insects, which 
walk very slowly, manage to get out of the way of enemies by 
expelling the water in their intestine with considerable violence, 
and this projects them to some distance. 
When about to undergo its transformation the nymph leaves 
the water and crawls upon plants by the side. Then the skin 
Gries, Splits, and sets the perfect insect free. The larvae live 
A ( \ 
mm, 
ra | ) } 
iN 
NYMPH OF THE JLibellula AND THE PERFECT INSECT EMERGING. 
about a year before acquiring their full growth, and the nymph ts 
very active, and has the rudiments of wings. 
The 4schuite have a rounded and robust body, and three 
articulations to their lip. Some have enormous eyes, set close 
together, so that they nearly touch each other in the middle 
line, and others have their eyes, set wide apart. 
The engraving shows the metamorphosis of Mschna macu- 
latissima, On the right one of them is flying; immediately below, 
in the water, a nymph may be seen projecting her long under 
lip with its pincers; by its side is a larva in a quiet condition, 
