168 LIFE, IN ITS INTERMEDIATE FORMS. 
cut into numerous sharp teeth, and spines, or armed with 
one or more long and sharp claws, you will then have as 
accurate an idea as my powers of description can give of 
the strange conformation of the under-lip of the larva of 
the tribes of Libelhdina (Dragon-flies), which conceal the 
mouth and face precisely as I have supposed a similar con- 
struction of your lips would do yours. You will probably 
admit that your own visage would present an appearance 
not very engaging while concealed by such a mask ; but it 
would strike still more awe into the spectators were they 
to see you first open the two upper jaw-like plates, which 
would project from your temples like the blinders of a 
horse ; and next, having, by means of the joint at your 
chin, let down the whole apparatus, and uncovered your 
face, employ them in seizing any food that presented itself, 
and conveying it to your mouth.” 
Such is the larva, from which the pupa does not differ 
in any respect, except that the rudiments of the future 
wings are seen budding out from the thorax. It is no 
less active, no less fierce, no less voracious than the larva. 
When the timo of its transformation approaches, it crawls 
out of the water up some aquatic plant, or on a twig upon 
the bank, where it remains a while for the skin to dry. 
Presently, a crack appears down the back, and the fly 
begins to emerge, as represented in the lower left-hand 
figure of the accompanying engraving. As soon as the 
feet are free, it invariably bends backward, and hangs with 
its head downward, as if exhausted, for some minutes. 
Then it rears itself up, catches hold of the twig with its 
hooked feet, and draws the extremity of its body out of 
the pupa-case, leaving the latter firmly fixed by its own 
