48 CHAPTERS ON THE NATURAL HISTORY 



pearance, and with habits but little changed, dimply it has the 

 four rudimentary wing-cases somewhat larger, and it bears a 

 more general resemblance to the matured insect, while there is 

 scarcely any diminution in its activity or in its ravenous appetite 

 for all kinds of aquatic insects and their larva?. 



At this time, by an interesting operation, the too-small larval 

 skin is molted, and the soft, delicate pupa emerges therefrom, 

 soon to attain a larger size, and then to have its body walls, or 

 external skeleton, harden. Still later on, or along some time in 

 July, these brown, often hairy, immature creatures are seen to 

 climb up the stalks of the water plants, and cling thereto by 

 means of their three pairs of legs, just beneath the surface of the 

 water, or in some species above it. Then follows the most re- 

 markable of all metamorphoses. Down the middle of the back 

 there suddenly occurs a gaping rent, and from out of this, 

 tediously, the tender imago of the Dragon-fly emerges. Flabby 

 and soft, it slowly moves higher up the plant stalk upon which 

 the pupa had climbed. Here it listlessly clings for an hour or 

 more, during which time one may almost see the insect pass to 

 the perfected stage. Its wings and body walls harden, the beau- 

 tiful tints of the latter gradually become evident, and complete 

 maturity soon follows. The warm sun quickly dries its harden- 

 ing form, intensifying as it does so the gorgeous colors as they 

 appear, and the insect is soon seen to rustle its elegant wings, be- 

 stir itself, test the powers of the functions of some of its various 

 structures, and then in flight launch into the air. 



As a rule the duration of life of dragon-Hies is not long, and is 

 made up of their incessant consumption of the many insects upon 

 which they prey; of their extraordinary methods of mating; of 

 their egg-laying, shortly after which they perish. M'Lachlan has 

 remarked that these insects are "pre-eminently lovers of the 

 hottest sunshine (a few are somewhat crepuscular), and the most 

 powerful and daring on the wing in fine weather become inert 

 and comparatively lifeless when at rest in dull weather, allowing 

 themselves to be captured by the Angers without making any 

 effort to escape. Many of the larger species (/Eschua, etc.) have 

 a habit of affecting a particular twig or other resting place, like 

 a Flycatcher among birds, darting off after prey and making- 

 long excursions, but returning by the chosen spot." 



In various quarters of the globe superb specimens of fossil 

 dragon-flies have been discovered, and doubtless manv more of 



