DRAG ON-T LIES. 269 



In Kirby and Spence's well-known work, tliero is an a( count 

 of a still more strange prolongation of life. There are certain 

 Hies whose larvae feed on aphides, which live in their three 

 stages about six weeks. One of them had been cauglit when 

 half-grown, and, having been once or twice fed, was forgotten 

 for three montlis, when it was found to be alive. It actually 

 lived for a whole year without a particle of food, and, as is well 

 remarked, ' it had existed in the larva state more than eight 

 times as long as it would have lived in all its states, if it had 

 regularly undergone its metamorphoses, which is as extraordi- 

 nary a prolongation of life as if a man were to live 560 years.' 



Sometimes tlie May-flies are wonderfully numerous, the air 

 being filled with their swarms as they flutter up and down in 

 their strange flight, and the trees and banks covered with the 

 shed pellicles of the first-winged stage. Even in England I 

 have known the JMay-flies to be in such swarms that the 

 very trout could not be taken with the hook, so gorged were 

 they with the May-flies that fell by thousands into the water. 

 In some parts of Europe, however, the numbers of these insects 

 are so vast, that their bodies are collected into heaps and used 

 for manuring the fields. 



The next family is a very conspicuous one, and there is no 

 likelihood of mistaking one of them for any other kind of 

 insect. Scientifically these insects are termed Libeilulidae, and 

 they are mmiliarly'known as Dragon-flies or Horse-stingers, the 

 latter name being given them from an absurd notion that they 

 sting horses. It is curious to notice how widely and deeply 

 this idea has impressed itself upon the general mass of country 

 peojDle, and to see how terrified they are at the very idea of 

 touching a Dragon-fly. I suppose that the convul.<i\(:' jerkings 

 of the long-bodied Dragon-flies when captured have given rise 

 to this opinion. With regard to the name of Dragon-flies, it 

 is a very appropriate one, as we shall presently see. 



In these insects the body is always long, and in most cases 

 nearly cylindrical, though in some it is rather wide and flat- 

 tened. The wings are very large, powerful, translucent, 

 strongly veined, and of equal size ; and the meshes, or ' reticula- 

 tious,' are so close as to divide the wing into a very great num- 

 ber of cells. 



