206 THE BUTTERFLY VIVARIUM. 



first, and best defined genera, Libellula. The term 

 IMellula, one of the fanciful denominations invented 

 by Linnaeus, is said to be derived from the name of a 

 kind of water engine, consisting of a long lever, work- 

 ing by means of a balanced weight at one end ; and 

 as a Dragon-fly sits at rest on some aquatic plant its 

 long slender tail extending over the water, it has 

 certainly some resemblance, in miniature, to such an 

 engine. 



The detection of the facts which have allied the 

 existence of the graceful and glittering Dragon-fly 

 with that of a creeping aquatic creature of sombre 

 hue and generally repulsive appearance, is of com- 

 paratively recent occurrence. The impulse to observe 

 the transformations of insects having been once 

 given, the changes of the ugly aquatic larva referred 

 to, first into pupa stage, and then to the development 

 of the perfect insect, were no doubt watched and dis- 

 covered independently by several naturalists of the 

 seventeenth and eighteenth centuries, each fancying 

 himself the first discoverer. Gcedart was, no doubt, 

 among the first of these, and the detailed account 

 which he published of the extraordinary metamor- 

 phoses he detected, as he witnessed them for the 

 first time, are very striking, though detailed with 

 the utmost simplicity of style. He called his work 



