U16 THE STORY OF THE UNIVERSE 



ments begin to elongate. These elongations become 

 more and more marked with every change of skin. 

 One morning, in the month of June, some years ago, 

 I observed a full-grown larva, which had a glisten- 

 ing appearance, owing to the presence of a film of air 

 under the skin. I put if under the microscope, and, 

 having added a drop of water with a pipette, looked 

 through the glass. To my astonishment, the insect 

 was gone, and an empty skin_only remained. I then 

 caught a second specimen in a similar condition, and 

 put it under the microscope, hoping to see it come 

 out. Nor was I disappointed. Very few moments 

 had elapsed, when I had the satisfaction of seeing the 

 thorax open along the middle of the back; the two 

 sides turned over; the insect literally walked out of 

 itself, unfolded its wings, and in an instant flew up 

 to the window. Several times since, I have had the 

 pleasure of witnessing this marvelous change, and it 

 is really wonderful how rapidly it takes place : from 

 the moment when the skin first cracks, not ten seconds 

 are over before the insect has flown away. 



Another family of Neuroptera, the dragon-flies, 

 or horse-stingers, as they are sometimes called, from 

 a mistaken idea that they sting severely enough to 

 hurt a horse, though in fact they are quite harmless, 

 also spend their early days in the water. The larvae 

 are brown, sluggish, ugly creatures, with six legs. 

 They feed on small water-animals, for which they 

 wait very patiently, either at the bottom of the water 

 or on some aquatic plant. The lower jaws are at- 

 tached to a long folding rod; and when any unwary 

 little creature approaches too near the larva, this 



