486 THE MICROSCOPE. 



possible to fancy more strange-looking creatures. They 

 are short, comparatively thick, with movements heavy and 

 clumsy, and after shedding their skins become pupse; still 

 continuing to live in the water. The pupse differ from 

 the larvae principally in having four small scales on their 

 sides ; these conceal the future wings. While the Dragon- 

 fly continues in its aquatic state, both as larva and pupa, 

 it devours all the insects it can entrap; and as it only 

 moves slowly, it is furnished with a very curious apparatus 

 near its head, which it projects at pleasure, and uses 

 as a trap. This apparatus consists of a pair of very large, 

 jointed, moveable jaws, which the insect keeps closely 

 folded over its head, like a large mask, till it sees its 

 prey ; when it does, it creeps softly along till it is suffi- 

 ciently near, it then darts out those long, arm-like jaws, 

 and suddenly seizing its prey conveys it to its mouth. 

 When the Dragon-fly is about to emerge from its pupa- 

 case, it places itself on the brink of the pond, or on the 

 leaf of some water-plant sufficiently strong to bear its 

 weight, and there divests itself of its pupa-case. When the 

 perfect insect first appears, it has two very small wings ; 

 these gradually increase, the veins fill with coloured liquid 

 globules, and in a short time two other wings appear. As 

 soon as the wings are fully expanded, and have attained 

 their beautiful gauze-like texture, the Dragon-fly begins to 

 dart about, and slaughter every small insect that falls in 

 its way. 



Equally rapid, exactly steered, and unwearied in its flight, 

 is the Gnat. The wings of a Gnat have been calculated, 

 during its flight, to vibrate 3000 times in a minute : these 

 wonderful wings are covered on surface and edge with a fine 

 down or hair. The alternations of bright sunshine and rain 

 so commonly seen in March, are extremely favourable to 

 the appearance of Gnats. The first that appear are called 

 Winter midges (Trichocera hy emails) . As the spring ad- 

 vances, these Midges are succeeded by others somewhat 

 different, and as the weather becomes warmer, the true 

 Gnats appear. The sting of the Gnat (Culex pipiens) is well 

 known although the insects themselves, so very rapid in 

 their movements, are so much dreaded that very few 

 people care to examine the delicacy and elegance of their 



