224 LIFE AND HER CHILDREN. 
the way, he shoots this water out, and drives himself 
along much as we saw the octopus do, only that the 
dragon-fly grub goes forwards instead of backwards. 
So in a year he grows big and strong, and short 
wings begin to appear under his skin. Then he 
crawls listlessly to the top of a plant, and there 
dragging himself out of his covering, he gradu- 
ally expands his large gauze wings filled with 
delicate air channels, and shaking free his sharp- 
clawed feet, is at once ready for new victims. His 
large gleaming eyes with their thousands of windows 
(often 12,000, each with its 
own lens and cone and rod, 
see Fig. 77) espy a butterfly 
or a moth, and in an instant 
he is pursuing it, flying 
upwards, downwards, and 
f sideways, without turning, 
by means of the peculiar 
muscles by which his wings 
work upon his bulky shoul- 
Section of an Insect's Eye. ders, while his long body 
a, Nerve-mass of the eye ; b, serves as a rudder. And 
nerves springing from it ; ,, whe n he has caught his prey, 
the retina ; a, thread-like rods ^ r J > 
by which the picture is formed ; he tears it savagely with 
e, glass-like cones ; // lens-like his homy jaws, Scattering 
facets, of which each eye may . 
have from 10,000 to 20,000. lts shattered wings upon 
the ground. Much as we 
admire the beautiful colours and magnificent wings of 
the dragon-fly, we must admit that when he reckons 
back his ancestors through the dim ages to those 
distant coal-forests, he must look along a line of the 
most greedy and cruel marauders of the insect world 
