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 Libellulina (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 time 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 



